Validity of Wearable Activity Monitors during Cycling and Resistance Exercise.

PubMed

Boudreaux, Benjamin D; Hebert, Edward P; Hollander, Daniel B; Williams, Brian M; Cormier, Corinne L; Naquin, Mildred R; Gillan, Wynn W; Gusew, Emily E; Kraemer, Robert R

2018-03-01

The use of wearable activity monitors has seen rapid growth; however, the mode and intensity of exercise could affect the validity of heart rate (HR) and caloric (energy) expenditure (EE) readings. There is a lack of data regarding the validity of wearable activity monitors during graded cycling regimen and a standard resistance exercise. The present study determined the validity of eight monitors for HR compared with an ECG and seven monitors for EE compared with a metabolic analyzer during graded cycling and resistance exercise. Fifty subjects (28 women, 22 men) completed separate trials of graded cycling and three sets of four resistance exercises at a 10-repetition-maximum load. Monitors included the following: Apple Watch Series 2, Fitbit Blaze, Fitbit Charge 2, Polar H7, Polar A360, Garmin Vivosmart HR, TomTom Touch, and Bose SoundSport Pulse (BSP) headphones. HR was recorded after each cycling intensity and after each resistance exercise set. EE was recorded after both protocols. Validity was established as having a mean absolute percent error (MAPE) value of ≤10%. The Polar H7 and BSP were valid during both exercise modes (cycling: MAPE = 6.87%, R = 0.79; resistance exercise: MAPE = 6.31%, R = 0.83). During cycling, the Apple Watch Series 2 revealed the greatest HR validity (MAPE = 4.14%, R = 0.80). The BSP revealed the greatest HR accuracy during resistance exercise (MAPE = 6.24%, R = 0.86). Across all devices, as exercise intensity increased, there was greater underestimation of HR. No device was valid for EE during cycling or resistance exercise. HR from wearable devices differed at different exercise intensities; EE estimates from wearable devices were inaccurate. Wearable devices are not medical devices, and users should be cautious when using these devices for monitoring physiological responses to exercise.

The Effects of Exercise Intensity vs. Metabolic State on the Variability and Magnitude of Left Ventricular Twist Mechanics during Exercise

PubMed Central

Armstrong, Craig; Samuel, Jake; Yarlett, Andrew; Cooper, Stephen-Mark; Stembridge, Mike; Stöhr, Eric J.

2016-01-01

Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential responses of the heart to exercise. However, previously a large variability in LV twist mechanics during exercise has been observed, which complicates the interpretation of results. This study aimed to determine some of the physiological sources of variability in LV twist mechanics during exercise. Sixteen healthy males (age: 22 ± 4 years, V˙O2peak: 45.5 ± 6.9 ml∙kg-1∙min-1, range of individual anaerobic threshold (IAT): 32–69% of V˙O2peak) were assessed at rest and during exercise at: i) the same relative exercise intensity, 40%peak, ii) at 2% above IAT, and, iii) at 40%peak with hypoxia (40%peak+HYP). LV volumes were not significantly different between exercise conditions (P > 0.05). However, the mean margin of error of LV twist was significantly lower (F2,47 = 2.08, P < 0.05) during 40%peak compared with IAT (3.0 vs. 4.1 degrees). Despite the same workload and similar LV volumes, hypoxia increased LV twist and untwisting rate (P < 0.05), but the mean margin of error remained similar to that during 40%peak (3.2 degrees, P > 0.05). Overall, LV twist mechanics were linearly related to rate pressure product. During exercise, the intra-individual variability of LV twist mechanics is smaller at the same relative exercise intensity compared with IAT. However, the absolute magnitude (degrees) of LV twist mechanics appears to be associated with the prevailing rate pressure product. Exercise tests that evaluate LV twist mechanics should be standardised by relative exercise intensity and rate pressure product be taken into account when interpreting results. PMID:27100099

The Effects of Exercise Intensity vs. Metabolic State on the Variability and Magnitude of Left Ventricular Twist Mechanics during Exercise.

PubMed

Armstrong, Craig; Samuel, Jake; Yarlett, Andrew; Cooper, Stephen-Mark; Stembridge, Mike; Stöhr, Eric J

2016-01-01

Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential responses of the heart to exercise. However, previously a large variability in LV twist mechanics during exercise has been observed, which complicates the interpretation of results. This study aimed to determine some of the physiological sources of variability in LV twist mechanics during exercise. Sixteen healthy males (age: 22 ± 4 years, [Formula: see text]O2peak: 45.5 ± 6.9 ml∙kg-1∙min-1, range of individual anaerobic threshold (IAT): 32-69% of [Formula: see text]O2peak) were assessed at rest and during exercise at: i) the same relative exercise intensity, 40%peak, ii) at 2% above IAT, and, iii) at 40%peak with hypoxia (40%peak+HYP). LV volumes were not significantly different between exercise conditions (P > 0.05). However, the mean margin of error of LV twist was significantly lower (F2,47 = 2.08, P < 0.05) during 40%peak compared with IAT (3.0 vs. 4.1 degrees). Despite the same workload and similar LV volumes, hypoxia increased LV twist and untwisting rate (P < 0.05), but the mean margin of error remained similar to that during 40%peak (3.2 degrees, P > 0.05). Overall, LV twist mechanics were linearly related to rate pressure product. During exercise, the intra-individual variability of LV twist mechanics is smaller at the same relative exercise intensity compared with IAT. However, the absolute magnitude (degrees) of LV twist mechanics appears to be associated with the prevailing rate pressure product. Exercise tests that evaluate LV twist mechanics should be standardised by relative exercise intensity and rate pressure product be taken into account when interpreting results.

Evidence for β-adrenergic modulation of sweating during incremental exercise in habitually trained males.

PubMed

Amano, Tatsuro; Shitara, Yosuke; Fujii, Naoto; Inoue, Yoshimitsu; Kondo, Narihiko

2017-07-01

The aim of the present study was to determine the β-adrenergic contribution to sweating during incremental exercise in habitually trained males. Nine habitually trained and 11 untrained males performed incremental cycling until exhaustion (20 W/min). Bilateral forearm sweat rates (ventilated capsule) were measured at two skin sites that were transdermally administered via iontophoresis with either 1% propranolol (Propranolol, a nonselective β-adrenergic receptor antagonist) or saline (Control). The sweat rate was evaluated as a function of both relative (percentage of maximum workload) and absolute exercise intensities. The sweat rate at the Propranolol site was lower than the control during exercise at 80 (0.57 ± 0.21 and 0.45 ± 0.19 mg·cm -2 ·min -1 for Control and Propranolol, respectively) and 90% (0.74 ± 0.22 and 0.65 ± 0.17 mg·cm -2 ·min -1 , respectively) of maximum workload in trained males (all P < 0.05). By contrast, no between-site differences in sweat rates were observed in untrained counterparts (all P > 0.05). At the same absolute intensity, higher sweat rates on the control site were observed in trained males relative to the untrained during exercise at 160 (0.23 ± 0.20 and 0.04 ± 0.05 mg·cm -2 ·min -1 for trained and untrained, respectively) and 180 W (0.40 ± 0.20 and 0.13 ± 0.13 mg·cm -2 ·min -1 , respectively) (all P < 0.05), whereas this between-group difference was not observed at the Propranolol site (all P > 0.05). We show that the β-adrenergic mechanism does modulate sweating during exercise at a submaximal high relative intensity in habitually trained males. The β-adrenergic mechanism may in part contribute to the greater sweat production in habitually trained males than in untrained counterparts during exercise. NEW & NOTEWORTHY We demonstrated for the first time that the β-adrenergic mechanism does modulate sweating (i.e., β-adrenergic sweating) during exercise using a localized β-adrenoceptor blockade in humans in vivo. β-Adrenergic sweating was evident in habitually trained individuals during exercise at a submaximal high relative intensity (80-90% maximal work). This observation advances our understanding of human thermoregulation during exercise and of the mechanism that underlies sweat gland adaptation to habitual exercise training. Copyright © 2017 the American Physiological Society.

Anaerobic threshold determination through ventilatory and electromyographics parameters.

PubMed

Gassi, E R; Bankoff, A D P

2010-01-01

The aim of present study was to compare the alterations in electromyography signs with Ventilatory Threshold (VT). Had been part of the study eight men, amateur cyclists and triathletes (25.25 +/- 6.96 years), that they had exercised themselves in a mechanical cicloergometer, a cadence of 80 RPM and with the increased intensity being in 25 W/min until the exhaustion. The VT was determined by a non-linear increase in VE/VO2 without any increase in VE/VCO2 and compared with the intensity corresponding to break point of amplitude EMG sign during the incremental exercise. The EMG--Fatigue Threshold (FT) and Ventilatory Threshold (VT) parameters used were the power, the time, absolute and relative VO2, ventilation (VE), the heart hate (HH) and the subjective perception of the effort. The results had not shown to difference in none of the variable selected for the corresponding intensity to VT and FT--EMG of the muscles lateralis vastus and femoris rectus. The parameters used in the comparison between the electromyographic indicators and ventilatory were the load, the time, absolute VO2 and relative to corporal mass, to ventilation (VE), the heart frequency (HH) and the Subjective Perception of the Effort (SPE).

Acute ethanol and taurine intake affect absolute alpha power in frontal cortex before and after exercise.

PubMed

Paulucio, Dailson; da Costa, Bruno M; Santos, Caleb G; Velasques, Bruna; Ribeiro, Pedro; Gongora, Mariana; Cagy, Mauricio; Alvarenga, Renato L; Pompeu, Fernando A M S

2017-09-14

Taurine and alcohol has been popularly ingested through energy drinks. Reports from both compounds shows they are active on nervous system but little is known about the acute effect of these substances on the frontal cortex in an exercise approach. The aim of this study was to determine the effects of 0,6mldL -1 of ethanol (ET), 6g of taurine (TA), and taurine with ethanol (TA+ET) intake on absolute alpha power (AAP) in the frontal region, before and after exercise. Nine participants were recruited, five women (22±3years) and four men (26±5years), for a counterbalanced experimental design. For each treatment, the tests were performed considering three moments: "baseline", "peak" and "post-exercise". In the placebo treatment (PL), the frontal areas showed AAP decrease at the post-exercise. However, in the TA, AAP decreased at peak and increased at post-exercise. In the ET treatment, AAP increased at the peak moment for the left frontal electrodes. In the TA+ET treatment, an AAP increase was observed at peak, and it continued after exercise ended. These substances were able to produce electrocortical activity changes in the frontal regions after a short duration and low intensity exercise. Left and right regions showed different AAP dynamics during peak and post-exercise moments when treatments were compared. Copyright © 2017 Elsevier B.V. All rights reserved.

The Effect of Variation of Plyometric Push-Ups on Force-Application Kinetics and Perception of Intensity.

PubMed

Dhahbi, Wissem; Chaouachi, Anis; Dhahbi, Anis Ben; Cochrane, Jodie; Chèze, Laurence; Burnett, Angus; Chamari, Karim

2017-02-01

To examine differences between ground-reaction-force (GRF)-based parameters collected from 5 types of plyometric push-ups. Between-trials reliability and the relationships between parameters were also assessed. Thirty-seven highly active commando soldiers performed 3 trials of 5 variations of the plyometric push-up in a counterbalanced order: standard countermovement push-up (SCPu), standard squat push-up (SSPu), kneeling countermovement push-up (KCPu), kneeling squat push-up (KSPu), and drop-fall push-up (DFPu). Vertical GRF was measured during these exercises using a portable Kistler force plate. The GRF applied by the hands in the starting position (initial force supported), peak GRF and rate of force development during takeoff, flight time, impact force, and rate of force development impact on landing were determined. During standard-position exercises (SCPu and SSPu) the initial force supported and impact force were higher (P < .001) than with kneeling exercises (KCPu, KSPu, and DFPu). The peak GRF and rate of force development during takeoff were higher (P < .001) in the countermovement push-up exercises ([CMP] SCPu, KCPu, and DFPu) than squat push-up exercises ([SP] SSPu and KSPu). Furthermore, the flight time was greater (P < .001) during kneeling exercises than during standard-position exercises. A significant relationship (P < .01) between impact force and the rate of force development impact was observed for CMP and SP exercises (r = .83 and r = .62, respectively). The initial force supported was also negatively related (P < .01) to the flight time for both CMP and SP (r = -.74 and r = -.80, respectively). It was revealed that the initial force supported and the peak GRF during takeoff had excellent reliability; however, other parameters had poor absolute reliability. It is possible to adjust the intensity of plyometric push-up exercises and train athletes' muscle power by correctly interpreting GRF-based parameters. However, caution is required as some parameters had marginal absolute reliability.

Whole body vibration exercise training for fibromyalgia.

PubMed

Bidonde, Julia; Busch, Angela J; van der Spuy, Ina; Tupper, Susan; Kim, Soo Y; Boden, Catherine

2017-09-26

Exercise training is commonly recommended for adults with fibromyalgia. We defined whole body vibration (WBV) exercise as use of a vertical or rotary oscillating platform as an exercise stimulus while the individual engages in sustained static positioning or dynamic movements. The individual stands on the platform, and oscillations result in vibrations transmitted to the subject through the legs. This review is one of a series of reviews that replaces the first review published in 2002. To evaluate benefits and harms of WBV exercise training in adults with fibromyalgia. We searched the Cochrane Library, MEDLINE, Embase, CINAHL, PEDro, Thesis and Dissertation Abstracts, AMED, WHO ICTRP, and ClinicalTrials.gov up to December 2016, unrestricted by language, to identify potentially relevant trials. We included randomized controlled trials (RCTs) in adults with the diagnosis of fibromyalgia based on published criteria including a WBV intervention versus control or another intervention. Major outcomes were health-related quality of life (HRQL), pain intensity, stiffness, fatigue, physical function, withdrawals, and adverse events. Two review authors independently selected trials for inclusion, extracted data, performed risk of bias assessments, and assessed the quality of evidence for major outcomes using the GRADE approach. We used a 15% threshold for calculation of clinically relevant differences. We included four studies involving 150 middle-aged female participants from one country. Two studies had two treatment arms (71 participants) that compared WBV plus mixed exercise plus relaxation versus mixed exercise plus relaxation and placebo WBV versus control, and WBV plus mixed exercise versus mixed exercise and control; two studies had three treatment arms (79 participants) that compared WBV plus mixed exercise versus control and mixed relaxation placebo WBV. We judged the overall risk of bias as low for selection (random sequence generation), detection (objectively measured outcomes), attrition, and other biases; as unclear for selection bias (allocation concealment); and as high for performance, detection (self-report outcomes), and selective reporting biases.The WBV versus control comparison reported on three major outcomes assessed at 12 weeks post intervention based on the Fibromyalgia Impact Questionnaire (FIQ) (0 to 100 scale, lower score is better). Results for HRQL in the control group at end of treatment (59.13) showed a mean difference (MD) of -3.73 (95% confidence interval [CI] -10.81 to 3.35) for absolute HRQL, or improvement of 4% (11% better to 3% worse) and relative improvement of 6.7% (19.6% better to 6.1% worse). Results for withdrawals indicate that 14 per 100 and 10 per 100 in the intervention and control groups, respectively, withdrew from the intervention (RR 1.43, 95% CI 0.27 to 7.67; absolute change 4%, 95% CI 16% fewer to 24% more; relative change 43% more, 95% CI 73% fewer to 667% more). The only adverse event reported was acute pain in the legs, for which one participant dropped out of the program. We judged the quality of evidence for all outcomes as very low. This study did not measure pain intensity, fatigue, stiffness, or physical function. No outcomes in this comparison met the 15% threshold for clinical relevance.The WBV plus mixed exercise (aerobic, strength, flexibility, and relaxation) versus control study (N = 21) evaluated symptoms at six weeks post intervention using the FIQ. Results for HRQL at end of treatment (59.64) showed an MD of -16.02 (95% CI -31.57 to -0.47) for absolute HRQL, with improvement of 16% (0.5% to 32%) and relative change in HRQL of 24% (0.7% to 47%). Data showed a pain intensity MD of -28.22 (95% CI -43.26 to -13.18) for an absolute difference of 28% (13% to 43%) and a relative change of 39% improvement (18% to 60%); as well as a fatigue MD of -33 (95% CI -49 to -16) for an absolute difference of 33% (16% to 49%) and relative difference of 47% (95% CI 23% to 60%); and a stiffness MD of -26.27 (95% CI -42.96 to -9.58) for an absolute difference of 26% (10% to 43%) and a relative difference of 36.5% (23% to 60%). All-cause withdrawals occurred in 8 per 100 and 33 per 100 withdrawals in the intervention and control groups, respectively (two studies, N = 46; RR 0.25, 95% CI 0.06 to 1.12) for an absolute risk difference of 24% (3% to 51%). One participant exhibited a mild anxiety attack at the first session of WBV. No studies in this comparison reported on physical function. Several outcomes (based on the findings of one study) in this comparison met the 15% threshold for clinical relevance: HRQL, pain intensity, fatigue, and stiffness, which improved by 16%, 39%, 46%, and 36%, respectively. We found evidence of very low quality for all outcomes.The WBV plus mixed exercise versus other exercise provided very low quality evidence for all outcomes. Investigators evaluated outcomes on a 0 to 100 scale (lower score is better) for pain intensity (one study, N = 23; MD -16.36, 95% CI -29.49 to -3.23), HRQL (two studies, N = 49; MD -6.67, 95% CI -14.65 to 1.31), fatigue (one study, N = 23; MD -14.41, 95% CI -29.47 to 0.65), stiffness (one study, N = 23; MD -12.72, 95% CI -26.90 to 1.46), and all-cause withdrawal (three studies, N = 77; RR 0.72, 95% CI -0.17 to 3.11). Adverse events reported for the three studies included one anxiety attack at the first session of WBV and one dropout from the comparison group ("other exercise group") due to an injury that was not related to the program. No studies reported on physical function. Whether WBV or WBV in addition to mixed exercise is superior to control or another intervention for women with fibromyalgia remains uncertain. The quality of evidence is very low owing to imprecision (few study participants and wide confidence intervals) and issues related to risk of bias. These trials did not measure major outcomes such as pain intensity, stiffness, fatigue, and physical function. Overall, studies were few and were very small, which prevented meaningful estimates of harms and definitive conclusions about WBV safety.

Acute recovery from exercise in people with multiple sclerosis: an exploratory study on the effect of exercise intensities.

PubMed

Collett, Johnny; Meaney, Andy; Howells, Ken; Dawes, Helen

2017-03-01

Purpose A better understanding of how people with multiple sclerosis (pwMS) recover from exercise may help inform interventions. Methods We explored physiological and perceptual responses following exercise of different intensities, using a crossover exposure-response design, in 14 adults with multiple sclerosis (MS) and 9 controls. A cycling exercise test determined maximum capacity (Wpeak). Participants then performed 20-min exercise sessions relative to Wpeak (random order separated by 7 days): (1) 45% and (2) 60% continuous cycling and (3) 90% intermittent cycling (30 s cycling, 30 s rest). During a 45-min recovery period, tympanic temperature (Temp°C), exertion in breathing (RPEbr) and legs (RPEleg), and cortical excitability (MEParea) were measured. Results Eleven pwMS and eight controls completed the study. Controls performed better on the exercise test (p < 0.05), thus more absolute work during subsequent sessions. PwMS took longer to recover RPEleg with recovery time increasing with intensity (45%-6 min; 60%-15 min; 90%-35 min) and correlating with Temp°C. MEParea was significantly depressed in both groups at 45% and 60% (p < 0.001), in the MS group this also correlated with RPEleg. Conclusions Feelings of leg exertion may persist after exercise in some pwMS, especially at high intensities. This may relate to body temperature and, after continuous exercise, cortical excitability. These results support considering the recovery period post exercise and provide an insight into potential correlates of post-exercise fatigue. Implications for Rehabilitation A better understanding of how pwMS recover following exercise may help inform exercise prescription a long side fatigue management. This study showed that, in pwMS, the time taken to recover from feelings of leg fatigue increased with the intensity of the exercise session rather that total work performed and was related to increase in body temperature. The results of this relatively small study support the need to consider a recovery period after exercise and provide an insight into potential physiological correlates.

Water intake accelerates parasympathetic reactivation after high-intensity exercise.

PubMed

Peçanha, Tiago; Paula-Ribeiro, Marcelle; Campana-Rezende, Edson; Bartels, Rhenan; Marins, João Carlos; de Lima, Jorge Roberto

2014-10-01

It has been shown that water intake (WI) improves postexercise parasympathetic recovery after moderate-intensity exercise session. However, the potential cardiovascular benefit promoted by WI has not been investigated after high-intensity exercise. To assess the effects of WI on post high-intensity parasympathetic recovery. Twelve recreationally active young men participated in the study (22 ± 1.4 years, 24.1 ± 1.6 kg.m(-2)). The experimental protocol consisted of two visits to the laboratory. Each visit consisted in the completion of a 30-min high-intensity [~80% of maximal heart rate (HR)] cycle ergometer aerobic session performing randomly the WI or control (CON, no water consumption) intervention at the end of the exercise. HR and RR intervals (RRi) were continuously recorded by a heart rate monitor before, during and after the exercise. Differences in HR recovery [e.g., absolute heart rate decrement after 1 min of recovery (HRR60s) and time-constant of the first order exponential fitting curve of the HRR (HRRτ)] and in postexercise vagal-related heart rate variability (HRV) indexes (rMSSD30s, rMSSD, pNN50, SD1 and HF) were calculated and compared for WI and CON. A similar HR recovery and an increased postexercise HRV [SD1 = 9.4 ± 5.9 vs. 6.0 ± 3.9 millisecond, HF(ln) = 3.6 ± 1.4 vs. 2.4 ± 1.3 millisecond(2), for WI and CON, respectively; p < .05] was observed in WI compared with CON. The results suggest that WI accelerates the postexercise parasympathetic reactivation after high-intensity exercise. Such outcome reveals an important cardioprotective effect of WI.

Aerobic exercise training for adults with fibromyalgia.

PubMed

Bidonde, Julia; Busch, Angela J; Schachter, Candice L; Overend, Tom J; Kim, Soo Y; Góes, Suelen M; Boden, Catherine; Foulds, Heather Ja

2017-06-21

Exercise training is commonly recommended for individuals with fibromyalgia. This review is one of a series of reviews about exercise training for people with fibromyalgia that will replace the "Exercise for treating fibromyalgia syndrome" review first published in 2002. • To evaluate the benefits and harms of aerobic exercise training for adults with fibromyalgia• To assess the following specific comparisons ० Aerobic versus control conditions (eg, treatment as usual, wait list control, physical activity as usual) ० Aerobic versus aerobic interventions (eg, running vs brisk walking) ० Aerobic versus non-exercise interventions (eg, medications, education) We did not assess specific comparisons involving aerobic exercise versus other exercise interventions (eg, resistance exercise, aquatic exercise, flexibility exercise, mixed exercise). Other systematic reviews have examined or will examine these comparisons (Bidonde 2014; Busch 2013). We searched the Cochrane Library, MEDLINE, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Physiotherapy Evidence Database (PEDro), Thesis and Dissertation Abstracts, the Allied and Complementary Medicine Database (AMED), the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), and the ClinicalTrials.gov registry up to June 2016, unrestricted by language, and we reviewed the reference lists of retrieved trials to identify potentially relevant trials. We included randomized controlled trials (RCTs) in adults with a diagnosis of fibromyalgia that compared aerobic training interventions (dynamic physical activity that increases breathing and heart rate to submaximal levels for a prolonged period) versus no exercise or another intervention. Major outcomes were health-related quality of life (HRQL), pain intensity, stiffness, fatigue, physical function, withdrawals, and adverse events. Two review authors independently selected trials for inclusion, extracted data, performed a risk of bias assessment, and assessed the quality of the body of evidence for major outcomes using the GRADE approach. We used a 15% threshold for calculation of clinically relevant differences between groups. We included 13 RCTs (839 people). Studies were at risk of selection, performance, and detection bias (owing to lack of blinding for self-reported outcomes) and had low risk of attrition and reporting bias. We prioritized the findings when aerobic exercise was compared with no exercise control and present them fully here.Eight trials (with 456 participants) provided low-quality evidence for pain intensity, fatigue, stiffness, and physical function; and moderate-quality evidence for withdrawals and HRQL at completion of the intervention (6 to 24 weeks). With the exception of withdrawals and adverse events, major outcome measures were self-reported and were expressed on a 0 to 100 scale (lower values are best, negative mean differences (MDs)/standardized mean differences (SMDs) indicate improvement). Effects for aerobic exercise versus control were as follows: HRQL: mean 56.08; five studies; N = 372; MD -7.89, 95% CI -13.23 to -2.55; absolute improvement of 8% (3% to 13%) and relative improvement of 15% (5% to 24%); pain intensity: mean 65.31; six studies; N = 351; MD -11.06, 95% CI -18.34 to -3.77; absolute improvement of 11% (95% CI 4% to 18%) and relative improvement of 18% (7% to 30%); stiffness: mean 69; one study; N = 143; MD -7.96, 95% CI -14.95 to -0.97; absolute difference in improvement of 8% (1% to 15%) and relative change in improvement of 11.4% (21.4% to 1.4%); physical function: mean 38.32; three studies; N = 246; MD -10.16, 95% CI -15.39 to -4.94; absolute change in improvement of 10% (15% to 5%) and relative change in improvement of 21.9% (33% to 11%); and fatigue: mean 68; three studies; N = 286; MD -6.48, 95% CI -14.33 to 1.38; absolute change in improvement of 6% (12% improvement to 0.3% worse) and relative change in improvement of 8% (16% improvement to 0.4% worse). Pooled analysis resulted in a risk ratio (RR) of moderate quality for withdrawals (17 per 100 and 20 per 100 in control and intervention groups, respectively; eight studies; N = 456; RR 1.25, 95%CI 0.89 to 1.77; absolute change of 5% more withdrawals with exercise (3% fewer to 12% more).Three trials provided low-quality evidence on long-term effects (24 to 208 weeks post intervention) and reported that benefits for pain and function persisted but did not for HRQL or fatigue. Withdrawals were similar, and investigators did not assess stiffness and adverse events.We are uncertain about the effects of one aerobic intervention versus another, as the evidence was of low to very low quality and was derived from single trials only, precluding meta-analyses. Similarly, we are uncertain of the effects of aerobic exercise over active controls (ie, education, three studies; stress management training, one study; medication, one study) owing to evidence of low to very low quality provided by single trials. Most studies did not measure adverse events; thus we are uncertain about the risk of adverse events associated with aerobic exercise. When compared with control, moderate-quality evidence indicates that aerobic exercise probably improves HRQL and all-cause withdrawal, and low-quality evidence suggests that aerobic exercise may slightly decrease pain intensity, may slightly improve physical function, and may lead to little difference in fatigue and stiffness. Three of the reported outcomes reached clinical significance (HRQL, physical function, and pain). Long-term effects of aerobic exercise may include little or no difference in pain, physical function, and all-cause withdrawal, and we are uncertain about long-term effects on remaining outcomes. We downgraded the evidence owing to the small number of included trials and participants across trials, and because of issues related to unclear and high risks of bias (performance, selection, and detection biases). Aerobic exercise appears to be well tolerated (similar withdrawal rates across groups), although evidence on adverse events is scarce, so we are uncertain about its safety.

The influence of high-intensity compared with moderate-intensity exercise training on cardiorespiratory fitness and body composition in colorectal cancer survivors: a randomised controlled trial.

PubMed

Devin, James L; Sax, Andrew T; Hughes, Gareth I; Jenkins, David G; Aitken, Joanne F; Chambers, Suzanne K; Dunn, Jeffrey C; Bolam, Kate A; Skinner, Tina L

2016-06-01

Following colorectal cancer diagnosis and anti-cancer therapy, declines in cardiorespiratory fitness and body composition lead to significant increases in morbidity and mortality. There is increasing interest within the field of exercise oncology surrounding potential strategies to remediate these adverse outcomes. This study compared 4 weeks of moderate-intensity exercise (MIE) and high-intensity exercise (HIE) training on peak oxygen consumption (V̇O2peak) and body composition in colorectal cancer survivors. Forty seven post-treatment colorectal cancer survivors (HIE = 27 months post-treatment; MIE = 38 months post-treatment) were randomised to either HIE [85-95 % peak heart rate (HRpeak)] or MIE (70 % HRpeak) in equivalence with current physical activity guidelines and completed 12 training sessions over 4 weeks. HIE was superior to MIE in improving absolute (p = 0.016) and relative (p = 0.021) V̇O2peak. Absolute (+0.28 L.min(-1), p < 0.001) and relative (+3.5 ml.kg(-1).min(-1), p < 0.001) V̇O2 peak were increased in the HIE group but not the MIE group following training. HIE led to significant increases in lean mass (+0.72 kg, p = 0.002) and decreases in fat mass (-0.74 kg, p < 0.001) and fat percentage (-1.0 %, p < 0.001), whereas no changes were observed for the MIE group. There were no severe adverse events. In response to short-term training, HIE is a safe, feasible and efficacious intervention that offers clinically meaningful improvements in cardiorespiratory fitness and body composition for colorectal cancer survivors. HIE appears to offer superior improvements in cardiorespiratory fitness and body composition in comparison to current physical activity recommendations for colorectal cancer survivors and therefore may be an effective clinical utility following treatment.

Acute effects of exercise on mood and EEG activity in healthy young subjects: a systematic review.

PubMed

Lattari, Eduardo; Portugal, Eduardo; Moraes, Helena; Machado, Sérgio; Santos, Tony M; Deslandes, Andrea C

2014-01-01

Electroencephalography has been used to establish the relationship among cortical activity, exercise and mood, such as asymmetry, absolute and relative power. The purpose of this study was to systematically review the influence of cortical activity on mood state induced by exercise. The Preferred Reporting Items in Systematic reviews and Meta-Analyses was followed in this study. The studies were retrieved from MEDLINE/PubMed, ISI Web of Knowledge and SciELO. Search was conducted in all databases using the following terms: EEG asymmetry, sLORETA, exercise, with affect, mood and emotions. Based on the defined criteria, a total of 727 articles were found in the search conducted in the literature (666 in Pubmed, 54 in ISI Web of Science, 2 in SciELO and 5 in other data sources). Total of 11 studies were selected which properly met the criteria for this review. Nine out of 11 studies used the frontal asymmetry, four used absolute and relative power and one used sLORETA. With regard to changes in cortical activity and mood induced by exercise, six studies attributed this result to different intensities, one to duration, one to type of exercise and one to fitness level. In general, EEG measures showed contradictory evidence of its ability to predict or modulate psychological mood states through exercise intervention.

Physical Activity Assessment Between Consumer- and Research-Grade Accelerometers: A Comparative Study in Free-Living Conditions.

PubMed

Dominick, Gregory M; Winfree, Kyle N; Pohlig, Ryan T; Papas, Mia A

2016-09-19

Wearable activity monitors such as Fitbit enable users to track various attributes of their physical activity (PA) over time and have the potential to be used in research to promote and measure PA behavior. However, the measurement accuracy of Fitbit in absolute free-living conditions is largely unknown. To examine the measurement congruence between Fitbit Flex and ActiGraph GT3X for quantifying steps, metabolic equivalent tasks (METs), and proportion of time in sedentary activity and light-, moderate-, and vigorous-intensity PA in healthy adults in free-living conditions. A convenience sample of 19 participants (4 men and 15 women), aged 18-37 years, concurrently wore the Fitbit Flex (wrist) and ActiGraph GT3X (waist) for 1- or 2-week observation periods (n=3 and n=16, respectively) that included self-reported bouts of daily exercise. Data were examined for daily activity, averaged over 14 days and for minutes of reported exercise. Average day-level data included steps, METs, and proportion of time in different intensity levels. Minute-level data included steps, METs, and mean intensity score (0 = sedentary, 3 = vigorous) for overall reported exercise bouts (N=120) and by exercise type (walking, n=16; run or sports, n=44; cardio machine, n=20). Measures of steps were similar between devices for average day- and minute-level observations (all P values > .05). Fitbit significantly overestimated METs for average daily activity, for overall minutes of reported exercise bouts, and for walking and run or sports exercises (mean difference 0.70, 1.80, 3.16, and 2.00 METs, respectively; all P values < .001). For average daily activity, Fitbit significantly underestimated the proportion of time in sedentary and light intensity by 20% and 34%, respectively, and overestimated time by 3% in both moderate and vigorous intensity (all P values < .001). Mean intensity scores were not different for overall minutes of exercise or for run or sports and cardio-machine exercises (all P values > .05). Fitbit Flex provides accurate measures of steps for daily activity and minutes of reported exercise, regardless of exercise type. Although the proportion of time in different intensity levels varied between devices, examining the mean intensity score for minute-level bouts across different exercise types enabled interdevice comparisons that revealed similar measures of exercise intensity. Fitbit Flex is shown to have measurement limitations that may affect its potential utility and validity for measuring PA attributes in free-living conditions.

Effects of ovariectomy and exercise training intensity on energy substrate and hepatic lipid metabolism, and spontaneous physical activity in mice.

PubMed

Tuazon, Marc A; Campbell, Sara C; Klein, Dylan J; Shapses, Sue A; Anacker, Keith R; Anthony, Tracy G; Uzumcu, Mehmet; Henderson, Gregory C

2018-06-01

Menopause is associated with fatty liver, glucose dysregulation, increased body fat, and impaired bone quality. Previously, it was demonstrated that single sessions of high-intensity interval exercise (HIIE) are more effective than distance- and duration-matched continuous exercise (CE) on altering hepatic triglyceride (TG) metabolism and very-low density lipoprotein-TG (VLDL-TG) secretion. Six weeks training using these modalities was examined for effects on hepatic TG metabolism/secretion, glucose tolerance, body composition, and bone mineral density (BMD) in ovariectomized (OVX) and sham-operated (SHAM) mice. OVX and SHAM were assigned to distance- and duration-matched CE and HIIE, or sedentary control. Energy expenditure during exercise was confirmed to be identical between CE and HIIE and both similarly reduced post-exercise absolute carbohydrate oxidation and spontaneous physical activity (SPA). OVX vs. SHAM displayed impaired glucose tolerance and greater body fat despite lower hepatic TG, and these outcomes were not affected by training. Only HIIE increased hepatic AMPK in OVX and SHAM, but neither training type impacted VLDL-TG secretion. As expected, BMD was lower in OVX, and training did not affect long bones. The results reveal intensity-dependent effects on hepatic AMPK expression and general exercise effects on subsequent SPA and substrate oxidation that is independent of estrogen status. These findings support the notion that HIIE can impact aspects of liver physiology in females while the effects of exercise on whole body substrate selection appear to be independent of training intensity. However, neither exercise approach mitigated the impairment in glucose tolerance and elevated body fat occurring in OVX mice. Copyright © 2018 Elsevier Inc. All rights reserved.

Chronic endurance exercise training offsets the age-related attenuation in contraction-induced rapid vasodilation

PubMed Central

Hughes, William E.; Ueda, Kenichi

2016-01-01

Aging is associated with attenuated contraction-induced rapid onset vasodilation (ROV). We sought to examine whether chronic exercise training would improve ROV in older adults. Additionally, we examined whether a relationship between cardiorespiratory fitness and ROV exists in young and older adults. Chronically exercise-trained older adults (n = 16; 66 ± 2 yr, mean ± SE) performed single muscle contractions in the forearm and leg at various intensities. Brachial and femoral artery diameter and blood velocity were measured using Doppler ultrasound. Vascular conductance (VC) was calculated as the quotient of blood flow (ml/min) and mean arterial pressure (mmHg). These data were compared with our previously published work from an identical protocol in 16 older untrained (66 ± 1 yr, mean ± SE) and 14 young (23 ± 1 yr) adults. Peak (ΔVCpeak) and total vasodilator (VCtotal) responses were greater in trained compared with untrained older adults across leg exercise intensities (P < 0.05). There were no differences in responses between trained older and young adults in the arm or leg at any exercise intensity (P > 0.05). Comparison of ΔVCpeak in a subset of subjects at an absolute workload in the leg revealed that trained older adults exhibited augmented responses relative to untrained older adults. Exercise capacity (V̇o2 peak) was associated with ΔVCpeak and VCtotal across arm (r = 0.59–0.64) and leg exercise intensities (r = 0.55–0.68, P < 0.05) in older adults. Our data demonstrate that 1) chronic exercise training improves ROV in the arm and leg of trained older adults, such that age-related differences in ROV are abolished, and 2) VO2peak is associated with ΔVCpeak responses in both limbs of older adults. PMID:27032899

Chronic endurance exercise training offsets the age-related attenuation in contraction-induced rapid vasodilation.

PubMed

Hughes, William E; Ueda, Kenichi; Casey, Darren P

2016-06-01

Aging is associated with attenuated contraction-induced rapid onset vasodilation (ROV). We sought to examine whether chronic exercise training would improve ROV in older adults. Additionally, we examined whether a relationship between cardiorespiratory fitness and ROV exists in young and older adults. Chronically exercise-trained older adults (n = 16; 66 ± 2 yr, mean ± SE) performed single muscle contractions in the forearm and leg at various intensities. Brachial and femoral artery diameter and blood velocity were measured using Doppler ultrasound. Vascular conductance (VC) was calculated as the quotient of blood flow (ml/min) and mean arterial pressure (mmHg). These data were compared with our previously published work from an identical protocol in 16 older untrained (66 ± 1 yr, mean ± SE) and 14 young (23 ± 1 yr) adults. Peak (ΔVCpeak) and total vasodilator (VCtotal) responses were greater in trained compared with untrained older adults across leg exercise intensities (P < 0.05). There were no differences in responses between trained older and young adults in the arm or leg at any exercise intensity (P > 0.05). Comparison of ΔVCpeak in a subset of subjects at an absolute workload in the leg revealed that trained older adults exhibited augmented responses relative to untrained older adults. Exercise capacity (V̇o2 peak) was associated with ΔVCpeak and VCtotal across arm (r = 0.59-0.64) and leg exercise intensities (r = 0.55-0.68, P < 0.05) in older adults. Our data demonstrate that 1) chronic exercise training improves ROV in the arm and leg of trained older adults, such that age-related differences in ROV are abolished, and 2) VO2peak is associated with ΔVCpeak responses in both limbs of older adults. Copyright © 2016 the American Physiological Society.

Endurance Exercise in Hypoxia, Hyperoxia and Normoxia: Mitochondrial and Global Adaptations.

PubMed

Przyklenk, Axel; Gutmann, Boris; Schiffer, Thorsten; Hollmann, Wildor; Strueder, Heiko K; Bloch, Wilhelm; Mierau, Andreas; Gehlert, Sebastian

2017-07-01

We hypothesized short-term endurance exercise (EN) in hypoxia (HY) to exert decreased mitochondrial adaptation, peak oxygen consumption (VO 2peak ) and peak power output (PPO) compared to EN in normoxia (NOR) and hyperoxia (PER). 11 male subjects performed repeated unipedal cycling EN in HY, PER, and NOR over 4 weeks in a cross-over design. VO 2peak , PPO, rate of perceived exertion (RPE) and blood lactate (Bla) were determined pre- and post-intervention to assess physiological demands and adaptation. Skeletal muscle biopsies were collected to determine molecular mitochondrial signaling and adaptation. Despite reduced exercise intensity (P<0.05), increased Bla and RPE levels in HY revealed higher metabolic load compared to PER (P<0.05) and NOR (n.s.). PPO increased in all groups (P<0.05) while VO 2peak and mitochondrial signaling were unchanged (P>0.05). Electron transport chain complexes tended to increase in all groups with the highest increase in HY (n.s.). EN-induced mitochondrial adaptability and exercise capacity neither decreased significantly in HY nor increased in PER compared to NOR. Despite decreased exercise intensity, short term EN under HY may not necessarily impair mitochondrial adaptation and exercise capacity while PER does not augment adaptation. HY might strengthen adaptive responses under circumstances when absolute training intensity has to be reduced. © Georg Thieme Verlag KG Stuttgart · New York.

Human Muscle Protein Synthetic Responses during Weight-Bearing and Non-Weight-Bearing Exercise: A Comparative Study of Exercise Modes and Recovery Nutrition.

PubMed

Pasiakos, Stefan M; McClung, Holly L; Margolis, Lee M; Murphy, Nancy E; Lin, Gregory G; Hydren, Jay R; Young, Andrew J

2015-01-01

Effects of conventional endurance (CE) exercise and essential amino acid (EAA) supplementation on protein turnover are well described. Protein turnover responses to weighted endurance exercise (i.e., load carriage, LC) and EAA may differ from CE, because the mechanical forces and contractile properties of LC and CE likely differ. This study examined muscle protein synthesis (MPS) and whole-body protein turnover in response to LC and CE, with and without EAA supplementation, using stable isotope amino acid tracer infusions. Forty adults (mean ± SD, 22 ± 4 y, 80 ± 10 kg, VO 2peak 4.0 ± 0.5 L ∙ min(-1)) were randomly assigned to perform 90 min, absolute intensity-matched (2.2 ± 0.1 VO2 L ∙ m(-1)) LC (performed on a treadmill wearing a vest equal to 30% of individual body mass, mean ± SD load carried 24 ± 3 kg) or CE (cycle ergometry performed at the same absolute VO2 as LC) exercise, during which EAA (10 g EAA, 3.6 g leucine) or control (CON, non-nutritive) drinks were consumed. Mixed-muscle and myofibrillar MPS were higher during exercise for LC than CE (mode main effect, P < 0.05), independent of dietary treatment. EAA enhanced mixed-muscle and sarcoplasmic MPS during exercise, regardless of mode (drink main effect, P < 0.05). Mixed-muscle and sarcoplasmic MPS were higher in recovery for LC than CE (mode main effect, P < 0.05). No other differences or interactions (mode x drink) were observed. However, EAA attenuated whole-body protein breakdown, increased amino acid oxidation, and enhanced net protein balance in recovery compared to CON, regardless of exercise mode (P < 0.05). These data show that, although whole-body protein turnover responses to absolute VO2-matched LC and CE are the same, LC elicited a greater muscle protein synthetic response than CE.

Arm and Intensity-Matched Leg Exercise Induce Similar Inflammatory Responses.

PubMed

Leicht, Christof A; Paulson, Thomas A W; Goosey-Tolfrey, Victoria L; Bishop, Nicolette C

2016-06-01

The amount of active muscle mass can influence the acute inflammatory response to exercise, associated with reduced risk for chronic disease. This may affect those restricted to upper body exercise, for example, due to injury or disability. The purpose of this study was to compare the inflammatory responses for arm exercise and intensity-matched leg exercise. Twelve male individuals performed three 45-min constant load exercise trials after determination of peak oxygen uptake for arm exercise (V˙O2peak A) and cycling (V˙O2peak C): 1) arm cranking exercise at 60% V˙O2peak A, 2) moderate cycling at 60% V˙O2peak C, and 3) easy cycling at 60% V˙O2peak A. Cytokine, adrenaline, and flow cytometric analysis of monocyte subsets were performed before and up to 4 h postexercise. Plasma IL-6 increased from resting concentrations in all trials; however, postexercise concentrations were higher for arm exercise (1.73 ± 1.04 pg·mL) and moderate cycling (1.73 ± 0.95 pg·mL) compared with easy cycling (0.87 ± 0.41 pg·mL; P < 0.04). Similarly, the plasma IL-1ra concentration in the recovery period was higher for arm exercise (325 ± 139 pg·mL) and moderate cycling (316 ± 128 pg·mL) when compared with easy cycling (245 ± 77 pg·mL, P < 0.04). Arm exercise and moderate cycling induced larger increases in monocyte numbers and larger increases of the classical monocyte subset in the recovery period than easy cycling (P < 0.05). The postexercise adrenaline concentration was lowest for easy cycling (P = 0.04). Arm exercise and cycling at the same relative exercise intensity induces a comparable acute inflammatory response; however, cycling at the same absolute oxygen uptake as arm exercise results in a blunted cytokine, monocyte, and adrenaline response. Relative exercise intensity appears to be more important to the acute inflammatory response than modality, which is of major relevance for populations restricted to upper body exercise.

Is the deleterious effect of cryotherapy on proprioception mitigated by exercise?

PubMed

Ribeiro, F; Moreira, S; Neto, J; Oliveira, J

2013-05-01

This study aimed to examine the acute effects of cryotherapy on knee position sense and to determine the time period necessary to normalize joint position sense when exercising after cryotherapy. 12 subjects visited the laboratory twice, once for cryotherapy followed by 30 min of exercise on a cycloergometer and once for cryotherapy followed by 30 min of rest. Sessions were randomly determined and separated by 48 h. Cryotherapy was applied in the form of ice bag, filled with 1 kg of crushed ice, for 20 min. Knee position sense was measured at baseline, after cryotherapy and every 5 min after cryotherapy removal until a total of 30 min. The main effect of cryotherapy was significant showing an increase in absolute (F7,154=43.76, p<0.001) and relative (F7,154=7.97, p<0.001) errors after cryotherapy. The intervention after cryotherapy (rest vs. exercise) revealed a significant main effect only for absolute error (F7,154=4.05, p<0.001), i.e., when subjects exercised after cryotherapy, the proprioceptive acuity reached the baseline values faster (10 min vs. 15 min). Our results indicated that the deleterious effect of cryotherapy on proprioception is mitigated by low intensity exercise, being the time necessary to normalize knee position sense reduced from 15 to 10 min. © Georg Thieme Verlag KG Stuttgart · New York.

Neuromuscular Fatigue during Prolonged Exercise in Hypoxia.

PubMed

Jubeau, Marc; Rupp, Thomas; Temesi, John; Perrey, Stéphane; Wuyam, Bernard; Millet, Guillaume Y; Verges, Samuel

2017-03-01

Prolonged cycling exercise performance in normoxia is limited because of both peripheral and central neuromuscular impairments. It has been reported that cerebral perturbations are greater during short-duration exercise in hypoxia compared with normoxia. The purpose of this study was to test the hypothesis that central deficits are accentuated in hypoxia compared with normoxia during prolonged (three bouts of 80 min separated by 25 min) whole-body exercise at the same relative intensity. Ten subjects performed two sessions consisting of three 80-min cycling bouts at 45% of their relative maximal aerobic power in normoxia and hypoxia (FiO2 = 0.12). Before exercise and after each bout, maximal voluntary force, voluntary activation assessed with nerve stimulation and transcranial magnetic stimulation, corticospinal excitability (motor evoked potential), intracortical inhibition (cortical silent period), and electrical (M-wave) and contractile (twitch and doublet peak forces) properties of the knee extensors were measured. Prefrontal and motor cortical oxygenation was also recorded during each cycling bout in both conditions. A significant but similar force reduction (≈-22%) was observed at the end of exercise in normoxia and hypoxia. The modifications of voluntary activation assessed with transcranial magnetic stimulation and nerve stimulation, motor evoked potential, cortical silent period, and M-wave were also similar in both conditions. However, cerebral oxygenation was reduced in hypoxia compared with normoxia. These findings show that when performed at the same relative low intensity, prolonged exercise does not induce greater supraspinal fatigue in hypoxia compared with normoxia. Despite lower absolute exercise intensities in hypoxia, reduced brain O2 availability might contribute to similar amounts of central fatigue compared with normoxia.

The Effects of Exercise on Food Intake and Hunger: Relationship with Acylated Ghrelin and Leptin

PubMed Central

Vatansever-Ozen, Serife; Tiryaki-Sonmez, Gul; Bugdayci, Guler; Ozen, Guclu

2011-01-01

This study investigated the effects of a long bout of aerobic exercise on hunger and energy intake and circulating levels of leptin and acylated ghrelin. Ten healthy male subjects undertook two, 4 h trials in a randomized crossover design. In the exercise trial subjects ran for 105 min at 50% of maximal oxygen uptake and the last 15 min at 70% of maximal oxygen uptake followed by a 120 min rest period. In the control trial, subjects rested for 4 h. Subjects consumed a buffet test meal at 180 min during each trial. Hunger ratings, acylated ghrelin, leptin, glucose and insulin concentrations were measured at 0, 1, 2, 3 and 4 h. No differences were found at baseline values for hunger, acylated ghrelin, leptin, insulin and glucose for both trials (p > 0.05). The estimated energy expenditure of the exercise trial was 1550 ± 136 kcal. Exercise did not change subsequent absolute energy intake, but produced a significant decrease (p < 0.05) in relative energy intake. A two-way ANOVA revealed a significant (p < 0. 05) interaction effect for hunger and acylated ghrelin. In conclusion, this exercise regimen had a positive effect on reducing appetite which is related to reduced acylated ghrelin responses over time. This finding lends support for a role of exercise in weight management. Key points Physical exercise is a strategy used to counteract obesity, since it lowers the energetic balance by increasing energy expenditure. However, because any energy expended in exercise elevates the intensity of hunger and drives food consumption, it is pertinent to ask how effective exercise could be in helping people to lose weight or to prevent weight gain. The effects of exercise on hunger sensations and food intake are fairly controversial and depend on the intensity and duration of exercise. 120 min prolonged treadmill exercise with mix intensity, temporarily decreased hunger sensations, acylated ghrelin and relative energy intake. Variations in exercise intensity should theoretically be a useful means of weight loss. PMID:24149873

Effect of whole body vibration in energy expenditure and perceived exertion during intense squat exercise.

PubMed

Bertucci, William M; Arfaoui, Ahlem; Duc, Sebastien; Letellier, Thierry; Brikci, Abderrahim

2015-01-01

The purpose of this study was to investigate the effect of whole body vibration in oxygen uptake during intense squatting exercise with an added weight and whole body vibration compared with the same exercise without vibration. Nine male sub- jects performed three trials of dynamic squatting with an additional load of 50% of their body weight during 3 min. One trial without vibration, one trial with the frequency of 40 Hz and amplitude of 2 mm and one trial with the frequency of 40 Hz and amplitude of 4 mm. The results showed no difference between the three experimental trials in relative and absolute oxygen uptake. However, the metabolic power and energy expended in whole body vibration (2 mm) were significantly different from exercise without vibration. The data analysis also showed a significant difference in rating of perceived exertion with whole body vibration (4 mm) compared with the exercise without vibration. Results showed that the addition of vibration stimulus has an increase in the energy expenditure particularly with 40 Hz and 2 mm amplitude, suggesting that the high metabolic power during heavy resistance training could be increased by the addition of vibration stimulation. Involuntary contractions generated by the vibration can be used by coaches to increase the intensity of heavy resistance training or to increase the energy expended during the workouts if the goal is a decrease of body mass.

Protected by nature? Effects of strenuous physical exercise on FVIII activity in moderate and mild haemophilia A patients: a pilot study.

PubMed

Groen, W G; den Uijl, I E M; van der Net, J; Grobbee, D E; de Groot, Ph G; Fischer, K

2013-07-01

Increase of factor VIII activity (FVIII) after physical exercise has been reported in healthy subjects and small-scale studies in patients with coagulopathies. The aim was to study whether moderate and mild haemophilia A patients are able to increase their endogenous FVIII activity levels by physical activity. We studied changes in FVIII activity levels after high-intensity exercise in 15 haemophilia A patients, 20-39 years, eight with moderate, seven with mild haemophilia. Patients cycled until volitional exhaustion, blood samples were drawn before and 10 min after the exercise test. FVIII activity increased 2.5 times (range 1.8-7.0 times), for both severities. Absolute increases were markedly different: median 7 IU dL(-1) (range 3-9 IU dL(-1) ) in patients with moderate, compared to 15 IU dL(-1) (range 6-62 IU dL(-1) ) in mild haemophilia patients. VWF and VWFpp increased independently of severity; median 50% (range 8-123%) and median 165% (range 48-350%), respectively, reflecting acute release of VWF. These observations may be used to promote high-intensity activities before participating in sports for moderate and mild haemophilia A patients, to reduce bleeding risk. Further studies are warranted to fully appreciate the clinical significance of exercise on different levels of intensity in patients with mild and moderate haemophilia A. © 2013 John Wiley & Sons Ltd.

Plasma irisin levels progressively increase in response to increasing exercise workloads in young, healthy, active subjects.

PubMed

Daskalopoulou, Stella S; Cooke, Alexandra B; Gomez, Yessica-Haydee; Mutter, Andrew F; Filippaios, Andreas; Mesfum, Ertirea T; Mantzoros, Christos S

2014-09-01

Irisin, a recently discovered myokine, has been shown to induce browning of white adipose tissue, enhancing energy expenditure and mediating some of the beneficial effects of exercise. We aimed to estimate the time frame of changes in irisin levels after acute exercise and the effect of different exercise workloads and intensities on circulating irisin levels immediately post-exercise. In a pilot study, four healthy subjects (22.5±1.7 years) underwent maximal workload exercise (maximal oxygen consumption, VO2 max) and blood was drawn at prespecified intervals to define the time frame of pre- and post-exercise irisin changes over a 24-h period. In the main study, 35 healthy, non-smoking (23.0±3.3 years) men and women (n=20/15) underwent three exercise protocols ≥48-h apart, in random order: i) maximal workload (VO2 max); ii) relative workload (70% of VO2 max/10 min); and iii) absolute workload (75 W/10 min). Blood was drawn immediately pre-exercise and 3 min post-exercise. In the pilot study, irisin levels increased by 35% 3 min post-exercise, then dropped and remained relatively constant. In the main study, irisin levels post-exercise were significantly higher than those of pre-exercise after all workloads (all, P<0.001). Post-to-pre-exercise differences in irisin levels were significantly different between workloads (P=0.001), with the greatest increase by 34% following maximal workload (P=0.004 vs relative and absolute). Circulating irisin levels were acutely elevated in response to exercise, with a greater increase after maximal workload. These findings suggest that irisin release could be a function of muscle energy demand. Future studies need to determine the underlying mechanisms of irisin release and explore irisin's therapeutic potential. © 2014 European Society of Endocrinology.

Body fatness, body core temperature, and heat loss during moderate-intensity exercise.

PubMed

Limbaugh, Jayme D; Wimer, Gregory S; Long, Lynn H; Baird, William H

2013-11-01

This study examined the influence of body fatness on body core temperature and heat loss responses during moderate-intensity exercise. Nine men with lower body fat and eight men with higher body fat, matched for aerobic fitness, completed 1 h of recumbent cycling at the same absolute intensity in a warm environment (30 degrees C, 40% RH). Percent body fat was measured by hydrostatic weighing, using oxygen dilution to determine residual volume. Esophageal temperature (T(es)), mean skin temperature (T(sk)), and local sweat rate (m(sw)) were measured at rest and continuously during exercise while forearm blood flow (FBF) was measured at rest and every 10 min during exercise. The lower body fat and higher body fat groups were successfully matched for aerobic fitness, removing the influence of body fatness, given that V/O2(peak) was 50.72 +/- 7.34 and 50.43 +/- 5.01 ml x kg LBM(-1) x min(-1), respectively. When compared to lower body fat individuals, % body fat, body surface area (A(D)), and body mass were higher and A(D)/ mass was lower in higher body fat individuals. T(es), T(sk), FBF, m(sw), and the slope of m(sw):T(es) were not different between groups. Metabolic heat production was similar between the lower body fat (299.7 +/- 40.5 W x m(-2)) and higher body fat (288.1 +/- 30.6 W x m(-2)) subjects, respectively. Dry and evaporative heat loss, as well as heat storage during exercise, were not different between groups. These data suggest that there is no effect of body fatness on body core temperature or heat loss responses during moderate-intensity exercise in a warm environment.

Associations between cardiorespiratory responses to exercise and the C34T AMPD1 gene polymorphism in the HERITAGE Family Study.

PubMed

Rico-Sanz, J; Rankinen, T; Joanisse, D R; Leon, A S; Skinner, J S; Wilmore, J H; Rao, D C; Bouchard, C

2003-07-07

The associations of the C34T polymorphism of the adenosine monophosphate deaminase 1 (AMPD1) gene with cardiorespiratory phenotypes were tested during cycling exercise at absolute and relative power outputs progressing to exhaustion before and after endurance training for 20 wk in the HERITAGE Family Study cohort (n = 779). Since no blacks were mutant homozygotes (TT), only whites were considered for analysis (400 normal homozygotes, CC; 97 heterozygotes, CT; and 6 TT). For sedentary state, cycling at the absolute power output of 50 W resulted in a higher rating of perceived exertion in TT (P < 0.0001). At the relative intensity of 60% of Vo(2 max), stroke volume was lower in TT (P < 0.05). Maximal values for power output, systolic blood pressure, heart rate, Vco(2), and respiratory exchange ratio were lower in TT (P < 0.05). The cardiorespiratory training response at 50 W and at 60% of Vo(2 max) was similar across C34T-AMPD1 genotypes. However, the maximal values for ventilation, Vo(2), and Vco(2) during exercise increased less in TT (P < 0.01). The results indicate that subjects with the TT genotype at the C34T AMPD1 gene have diminished exercise capacity and cardiorespiratory responses to exercise in the sedentary state. Furthermore, the training response of ventilatory phenotypes during maximal exercise is more limited in TT.

Magnetic resonance imaging and electromyography as indexes of muscle function

NASA Technical Reports Server (NTRS)

Adams, Gregory R.; Duvoisin, Marc R.; Dudley, Gary A.

1992-01-01

A hypothesis is tested that exercise-induced magnetic resonance (MR) contrast shifts would relate to electromyography (EMG) amplitude if both measures reflect muscle use during exercise. Both magnetic resonance images (MRI) and EMG data were obtained for separate eccentric (ECC) and cocentric (CON) exercise of increasing intensity for seven subjects 30-32 yr old. CON and ECC actions caused increased integrated EMG (IEMG) and T2 values which were strongly related with relative resistance. The rate of increase and absolute value of both T2 and IEMG were found to be greater for CON than for ECC actions. For both actions IEMG and T2 were correlated. Data obtained suggest that surface IEMG accurately reflects the contractile behavior of muscle and exercise-induced increases in MRI T2 values reflect certain processes that scale with muscle use.

Role of fat metabolism in exercise.

PubMed

Askew, E W

1984-07-01

Fat and carbohydrate are the two major energy sources used during exercise. Either source can predominate, depending upon the duration and intensity of exercise, degree of prior physical conditioning, and the composition of the diet consumed in the days prior to a bout of exercise. Fatty acid oxidation can contribute 50 to 60 per cent of the energy expenditure during a bout of low intensity exercise of long duration. Strenuous submaximal exercise requiring 65 to 80 per cent of VO2 max will utilize less fat (10 to 45 per cent of the energy expended). Exercise training is accompanied by metabolic adaptations that occur in skeletal muscle and adipose tissue and that facilitate a greater delivery and oxidation of fatty acids during exercise. The trained state is characterized by an increased flux of fatty acids through smaller pools of adipose tissue energy. This is reflected by smaller, more metabolically active adipose cells in smaller adipose tissue depots. Peak blood concentrations of free fatty acids and ketone bodies are lower during and following exercise in trained individuals, probably due to increased capacity of the skeletal musculature to oxidize these energy sources. Trained individuals oxidize more fat and less carbohydrate than untrained subjects when performing submaximal work of the same absolute intensity. This increased capacity to utilize energy from fat conserves crucial muscle and liver glycogen stores and can contribute to increased endurance. Further benefits of the enhanced lipid metabolism accompanying chronic aerobic exercise training are decreased cardiac risk factors. Exercise training results in lower blood cholesterol and triglycerides and increased high density lipoprotein cholesterol. High-fat diets are not recommended because of their association with atherosclerotic heart disease. Recent evidence suggests that low-fat high-carbohydrate diets may increase blood triglycerides and reduce high density lipoproteins. This suggests that the chronic ingestion of diets that are extreme in their composition of either fat or carbohydrate should be approached with caution in health-conscious athletes, as well as in sedentary individuals.

A step towards personalized sports nutrition: carbohydrate intake during exercise.

PubMed

Jeukendrup, Asker

2014-05-01

There have been significant changes in the understanding of the role of carbohydrates during endurance exercise in recent years, which allows for more specific and more personalized advice with regard to carbohydrate ingestion during exercise. The new proposed guidelines take into account the duration (and intensity) of exercise and advice is not restricted to the amount of carbohydrate; it also gives direction with respect to the type of carbohydrate. Studies have shown that during exercise lasting approximately 1 h in duration, a mouth rinse or small amounts of carbohydrate can result in a performance benefit. A single carbohydrate source can be oxidized at rates up to approximately 60 g/h and this is the recommendation for exercise that is more prolonged (2-3 h). For ultra-endurance events, the recommendation is higher at approximately 90 g/h. Carbohydrate ingested at such high ingestion rates must be a multiple transportable carbohydrates to allow high oxidation rates and prevent the accumulation of carbohydrate in the intestine. The source of the carbohydrate may be a liquid, semisolid, or solid, and the recommendations may need to be adjusted downward when the absolute exercise intensity is low and thus carbohydrate oxidation rates are also low. Carbohydrate intake advice is independent of body weight as well as training status. Therefore, although these guidelines apply to most athletes, they are highly dependent on the type and duration of activity. These new guidelines may replace the generic existing guidelines for carbohydrate intake during endurance exercise.

Combination of body mass-based resistance training and high-intensity walking can improve both muscle size and V˙O2 peak in untrained older women.

PubMed

Ozaki, Hayao; Kitada, Tomoharu; Nakagata, Takashi; Naito, Hisashi

2017-05-01

Here, we aimed to compare the effect of a combination of body mass-based resistance exercise and moderate-intensity (55% peak oxygen uptake [ V˙O 2 peak]) walking or high-intensity (75% V˙O 2 peak) walking on muscle size and V˙O 2 peak in untrained older women. A total of 12 untrained older women (mean age 60 ± 2 years) were randomly assigned to either a moderate-intensity aerobic training group (n = 6) or high-intensity aerobic training group (n = 6). Both groups carried out body-mass based (lower body) resistance exercises (2 sets of 10 repetitions) on 3 days/week for 8 weeks. Between these exercises, the participants in the moderate-intensity aerobic training group walked at a previously determined speed equivalent to 55% V˙O 2 peak, whereas those in the high-intensity aerobic training group walked at a speed equivalent to 75% V˙O 2 peak. Muscle thickness of the anterior aspect of the thigh and maximal isokinetic knee extension strength significantly increased in both groups (P < 0.01); these relative changes were negatively correlated with the absolute muscle thickness of the anterior aspect of the thigh value and the relative value of maximal knee strength to body mass at pre-intervention, respectively. A significant group × time interaction was noted for V˙O 2 peak (P < 0.05), which increased only in the high-intensity aerobic training group. Body mass-based resistance training significantly induced muscle hypertrophy in untrained older women. In particular, lower muscle thickness before intervention was associated with greater training-induced growth. Furthermore, V˙O 2 peak can be increased by combined circuit training involving low-load resistance exercise and walking, particularly when a relatively high intensity of walking is maintained. Geriatr Gerontol Int 2017; 17: 779-784. © 2016 Japan Geriatrics Society.

Energy expenditure during an exercise training session for cardiac patients.

PubMed

Santa-Clara, Helena; Melo, Xavier; Willi, Romina; Pinto, Rita; Santos, Vanessa; Almeida, José P; Martins, Rodrigo; Clijsen, Ron; Mendes, Miguel; Fernhall, Bo

2018-03-01

Increasing energy expenditure (EE) in cardiac patients remains a challenge. Exercise approaches in cardiac rehabilitation/secondary prevention programs (CR/SP) have consistently resulted in minimal weight loss, due in part to the low exercise-related EE. The purpose of this study was to measure the EE among patients participating in a routine exercise session of Phase III maintenance CR/SP, where a recreational activity was introduced. Twelve overweight/obese male patients with coronary artery disease (aged 62.6 ± 8.5 years) had their total EE measured during a combined aerobic (circuit workout (ACW) and recreational activity) and resistance training (RT) session using a portable gas analyzer. Subjects were instructed to exercise at 60%-70% of heart rate reserve. Activity EE was calculated from total EE and resting EE. The duration of the session was 75.3 ± 1.5 min, of which 59.7 ± 8.8 min were above moderate intensity (3-6 METs). Activity EE was 309 ± 76 kcal, concurring to a total EE of 457 ± 80 kcal (3.9 ± 0.8 METs-h). ACW, recreational activity, and RT fulfilled 34.4% ± 6.4%, 25.0% ± 5.3%, and 14.2% ± 2.7% of the activity EE, respectively. Absolute intensities (METs) were significantly different between the RT (3.9 ± 1.0) and the ACW (6.9 ± 1.8) and recreational activity (5.9 ± 0.8). In conclusion, a combined aerobic and resistance training following standard exercise prescription practices, coupled with a recreational activity, is an effective tool to promote exercise above moderate intensity in male coronary artery disease patients. Clinicians can adopt concepts from recreational activity to develop CR/SP sessions.

Motor unit activation patterns during concentric wrist flexion in humans with different muscle fibre composition.

PubMed

Søgaard, K; Christensen, H; Fallentin, N; Mizuno, M; Quistorff, B; Sjøgaard, G

1998-10-01

Muscle activity was recorded from the flexor carpi radialis muscle during static and dynamic-concentric wrist flexion in six subjects, who had exhibited large differences in histochemically identified muscle fibre composition. Motor unit recruitment patterns were identified by sampling 310 motor units and counting firing rates in pulses per second (pps). During concentric wrist flexion at 30% of maximal exercise intensity the mean firing rate was 27 (SD 13) pps. This was around twice the value of 12 (SD 5) pps recorded during sustained static contraction at 30% of maximal voluntary contraction, despite a larger absolute force level during the static contraction. A similar pattern of higher firing rates during dynamic exercise was seen when concentric wrist flexion at 60% of maximal exercise intensity [30 (SD 14) pps] was compared with sustained static contraction at 60% of maximal voluntary contraction [19 (SD 8) pps]. The increase in dynamic exercise intensity was accomplished by recruitment of additional motor units rather than by increasing the firing rate as during static contractions. No difference in mean firing rates was found among subjects with different muscle fibre composition, who had previously exhibited marked differences in metabolic response during corresponding dynamic contractions. It was concluded that during submaximal dynamic contractions motor unit firing rate cannot be deduced from observations during static contractions and that muscle fibre composition may play a minor role.

Physical activity in the prevention and amelioration of osteoporosis in women : interaction of mechanical, hormonal and dietary factors.

PubMed

Borer, Katarina T

2005-01-01

Osteoporosis is a serious health problem that diminishes quality of life and levies a financial burden on those who fear and experience bone fractures. Physical activity as a way to prevent osteoporosis is based on evidence that it can regulate bone maintenance and stimulate bone formation including the accumulation of mineral, in addition to strengthening muscles, improving balance, and thus reducing the overall risk of falls and fractures. Currently, our understanding of how to use exercise effectively in the prevention of osteoporosis is incomplete. It is uncertain whether exercise will help accumulate more overall peak bone mass during childhood, adolescence and young adulthood. Also, the consistent effectiveness of exercise to increase bone mass, or at least arrest the loss of bone mass after menopause, is also in question. Within this framework, section 1 introduces mechanical characteristics of bones to assist the reader in understanding their responses to physical activity. Section 2 reviews hormonal, nutritional and mechanical factors necessary for the growth of bones in length, width and mineral content that produce peak bone mass in the course of childhood and adolescence using a large sample of healthy Caucasian girls and female adolescents for reference. Effectiveness of exercise is evaluated throughout using absolute changes in bone with the underlying assumption that useful exercise should produce changes that approximate or exceed the absolute magnitude of bone parameters in a healthy reference population. Physical activity increases growth in width and mineral content of bones in girls and adolescent females, particularly when it is initiated before puberty, carried out in volumes and at intensities seen in athletes, and accompanied by adequate caloric and calcium intakes. Similar increases are seen in young women following the termination of statural growth in response to athletic training, but not to more limited levels of physical activity characteristic of longitudinal training studies. After 9-12 months of regular exercise, young adult women often show very small benefits to bone health, possibly because of large subject attrition rates, inadequate exercise intensity, duration or frequency, or because at this stage of life accumulation of bone mass may be at its natural peak. The important influence of hormones as well as dietary and specific nutrient abundance on bone growth and health are emphasised, and premature bone loss associated with dietary restriction and estradiol withdrawal in exercise-induced amenorrhoea is described. In section 3, the same assessment is applied to the effects of physical activity in postmenopausal women. Studies of postmenopausal women are presented from the perspective of limitations of the capacity of the skeleton to adapt to mechanical stress of exercise due to altered hormonal status and inadequate intake of specific nutrients. After menopause, effectiveness of exercise to increase bone mineral depends heavily on adequate availability of dietary calcium. Relatively infrequent evidence that physical activity prevents bone loss or increases bone mineral after menopause may be a consequence of inadequate calcium availability or low intensity of exercise in training studies. Several studies with postmenopausal women show modest increases in bone mineral toward the norm seen in a healthy population in response to high-intensity training. Physical activities continue to stimulate increases in bone diameter throughout the lifespan. These exercise-stimulated increases in bone diameter diminish the risk of fractures by mechanically counteracting the thinning of bones and increases in bone porosity. Seven principles of bone adaptation to mechanical stress are reviewed in section 4 to suggest how exercise by human subjects could be made more effective. They posit that exercise should: (i) be dynamic, not static; (ii) exceed a threshold intensity; (iii) exceed a threshold strain frequency; (iv) be relatively brief but intermittent; (v) impose an unusual loading pattern on the bones; (vi) be supported by unlimited nutrient energy; and (vii) include adequate calcium and cholecalciferol (vitamin D3) availability.

Exercise reduces the intensity and prevalence of low back pain in 12-13 year old children: a randomised trial.

PubMed

Fanucchi, Gina L; Stewart, Aimee; Jordaan, Ronél; Becker, Piet

2009-01-01

Does an eight-week exercise program reduce the intensity and prevalence of low back pain in 12-13 year old children? Does it decrease the childhood physical risk factors for low back pain and promote a sense of well-being? Randomised trial with concealed allocation and assessor blinding. Seventy-two 12-13 year old children, who had complained of low back pain in the past three months. The experimental group completed eight exercise classes of 40-45 minutes duration over eight weeks conducted by a physiotherapist, whilst the control group received no intervention. The primary outcome was pain intensity measured on a 10-cm visual analogue scale. Secondary outcomes included 3-month prevalence of pain, childhood physical risk factors for low back pain, and sense of well-being. Measures were taken at baseline (Month 0), post-intervention (Month 3), and three months later (Month 6). Pain intensity over the past month had decreased by 2.2 cm (95% CI 1.0 to 3.5) more for the experimental group than the control group at Month 3 and was still 2.0 cm (95% CI 0.5 to 3.5) less than the control group at Month 6. The absolute risk reduction for 3-month prevalence in low back pain in the experimental group was 24% (95% CI 4 to 41) compared with the control group at Month 3, and 40% (95% CI 18 to 57) at Month 6. There were also statistically-significant between-group differences in neural mobility. Exercise is effective in reducing the intensity and prevalence of low back pain in children. Clinical trials NCT00786864.

Benefits, Consequences, and Uncertainties of Conventional (Exercise) Countermeasure Approaches

NASA Technical Reports Server (NTRS)

Ploutz-Snyder, Lori

2013-01-01

This presentation will review the pros, cons, and uncertainties of using exercise countermeasures in hypothetical long duration exploration missions. The use of artificial gravity and exercise will be briefly discussed. One benefit to continued use of exercise is related to our extensive experience with spaceflight exercise hardware and programming. Exercise has been a part of each space mission dating back to the 1960's when simple isometric and bungee exercises were performed in the Gemini capsule. Over the next 50 years, exercise hardware improved cumulating in today's ISS suite of exercise equipment: Cycle Ergometer with Vibration Isolation and Stabilization System (CEVIS), Treadmill (T2) and Advanced Resistive Exercise Device (ARED). Today's exercise equipment is the most robust ever to be flown in space and allows the variety and intensity of exercise that might reasonably be expected to maintain muscle mass and function, bone density and cardiovascular fitness. A second benefit is related to the large body of research literature on exercise training. There is a considerable body of supporting research literature including >40,000 peer reviewed research articles on exercise training in humans. A third benefit of exercise is its effectiveness. With the addition of T2 and ARED to our ISS exercise suite, crew member outcomes on standard medical tests have improved. Additionally exercise has other positive side effects such as stress relief, possible improvement of immune function, improved sleep, etc. Exercise is not without its consequences. The major cons to performance of in-flight exercise are the time and equipment required. Currently crew are scheduled 2.5 hrs/day for exercise and there is considerable cost to develop, fly and maintain exercise hardware. While no major injuries have been reported on ISS, there is always some risk of injury with any form of exercise There are several uncertainties going forward; these relate mostly to the development of small compact robust effective exercise devices for the next generation of space vehicles. It is becoming increasingly apparent that high intensity exercise is required for maintenance of fitness and functional capability and so future hardware will need to be developed, tested and implemented that allow for a wide variety of exercise, at high intensity while likely involving low mass, volume and power. There are many unanswered issues related to the minimum number and type of exercise devices required for exploration, optimizing exercise prescriptions for these devices, whether a treadmill is absolutely required, and even whether any single countermeasure can adequately protect muscle, bone, cardiovascular and sensorimotor function.

The rate of phosphocreatine hydrolysis and resynthesis in exercising muscle in humans using 31P-MRS.

PubMed

Yoshida, Takayoshi

2002-09-01

Time-resolved 31-phosphorus nuclear magnetic resonance spectroscopy (31P-MRS) of the biceps femoris muscles was performed during exercise and recovery in six healthy sedentary male subjects (maximal oxygen uptake; 46.6 +/- 1.7 (SEM) ml.kg-1.min-1), 5 male sprinters (56.2 +/- 2.5), and 5 male long-distance runners (73.6 +/- 2.2). Each performed 4 min of knee flexion exercises at absolute values of 1.63 W and 4.90 W, followed by 5 min of recovery in a prone position in a 2.1 T superconducting magnet with a 67 cm bore. 31P-MRS spectra were recorded every 12.8 s during the rest-exercise-recovery sequence. Computer-aided contour analysis and pixel imaging of phosphocreatine peaks (PCr) and inorganic phosphate (Pi) were performed. The work loads in the present study were selected as mild exercise (1.63 W) and heavy exercise (4.90 W), corresponding to 18-23% and 54-70% of maximal exercise intensity. Long-distance runners showed a significantly smaller decrement in PCr and less acidification at a given exercise intensity compared to those shown by sedentary subjects. The transient responses of PCr and Pi during recovery were characterized by first-order kinetics. After exercise, the recovery rates of PCr and Pi were significantly faster in long-distance runners than in sedentary subjects (P < 0.05). Since it is postulated that PCr resynthesis is controlled by aerobic metabolism and mitochondrial creatine kinase, it is suggested that the faster PCr and Pi recovery rates and decreased acidification seen in long-distance runners during and after exercise might be attributed to their greater capacity for aerobic metabolism.

Effect of gender on fatigue and recovery following maximal intensity repeated sprint performance.

PubMed

Laurent, C M; Green, J M; Bishop, P A; Sjökvist, J; Schumacker, R E; Richardson, M T; Curtner-Smith, M

2010-09-01

This study investigated the effects of gender on repeated, maximal-intensity intermittent sprint exercise following variable day-to-day recovery periods. Sixteen volunteers (8 men, 8 women) performed four trials of high-intensity intermittent sprint exercise consisting of three bouts of eight 30 m sprints (total of 24 sprints). Following completion of the baseline trial, in repeated-measures design, participants were assigned, in counter-balanced order, variable recovery periods of 24, 48, and 72 h whereupon they repeated an identical exercise trial. Results from a series of 4 (trial) x 3 (bout) repeated measures ANOVAs revealed men produced significantly (P < 0.01) faster times throughout all bouts and trials of repeated sprint exercise. Additionally, women exhibited significantly lower (P < 0.05) blood lactate concentration and significantly lower (P < 0.05) decrement in performance, indicating increased resistance to fatigue during repeated exercise sessions. There were no significant differences (P > 0.05) between genders for heart rate or rating of perceived exertion during or following trials. There were no significant differences for overall sprint performance within either gender among trials. These results indicate men, while able to produce higher absolute power outputs (i.e., lower sprint time), demonstrate higher decrement scores within a trial compared to women, thus suggesting women may recover faster and fatigue less. Also, gender differences affecting recovery within in a trial were observed to be diminished between trials (i.e., day-to-day recovery) of maximal intermittent sprint work evidenced by the observed stability of performance between trials following various recovery durations.

Effects of resistance or aerobic exercise training on total and regional body composition in sedentary overweight middle-aged adults.

PubMed

Donges, Cheyne E; Duffield, Rob

2012-06-01

The purpose of this study was to examine the effects of 10 weeks of aerobic endurance training (AET), resistance exercise training (RET), or a control (CON) condition on absolute and relative fat mass (FM) or fat-free mass (FFM) in the total body (TB) and regions of interest (ROIs) of sedentary overweight middle-aged males and females. Following prescreening, 102 subjects underwent anthropometric measurements, dual-energy X-ray absorptiometry, and strength and aerobic exercise testing. Randomized subjects (male RET, n = 16; female RET, n = 19; male AET, n = 16; and female AET, n = 25) completed supervised and periodized exercise programs (AET, 30-50 min cycling at 70%-75% maximal heart rate; RET, 2-4 sets × 8-10 repetitions of 5-7 exercises at 70%-75% 1 repetition maximum) or a nonexercising control condition (male CON, n = 13 and female CON, n = 13). Changes in absolute and relative TB-FM and TB-FFM and ROI-FM and ROI-FFM were determined. At baseline, and although matched for age and body mass index, males had greater strength, aerobic fitness, body mass, absolute and relative TB-FFM and ROI-FFM, but reduced absolute and relative TB-FM and ROI-FM, compared with females (p < 0.05). After training, both female exercise groups showed equivalent or greater relative improvements in strength and aerobic fitness than did the male exercise groups (p < 0.05); however, the male exercise groups increased TB-FFM and reduced TB-FM more than did the female exercise groups (p < 0.05). Male AET altered absolute FM more than male RET altered absolute FFM, thus resulting in a greater enhancement of relative FFM. Despite equivalent or greater responses to RET or AET by female subjects, the corresponding respective increases in FFM or reductions in FM were lower than those in males, indicating that a biased dose-response relationship exists between sexes following 10 weeks of exercise training.

Acute cardiorespiratory, perceptual and enjoyment responses to high-intensity interval exercise in adolescents.

PubMed

Malik, Adam A; Williams, Craig A; Bond, Bert; Weston, Kathryn L; Barker, Alan R

2017-11-01

This study aimed to examine adolescents' acute cardiorespiratory and perceptual responses during high-intensity interval exercise (HIIE) and enjoyment responses following HIIE and work-matched continuous moderate intensity exercise (CMIE). Fifty-four 12- to 15-year olds (27 boys) completed 8 × 1-min cycling at 90% peak power with 75-s recovery (HIIE) and at 90% of the gas exchange threshold (CMIE). Absolute oxygen uptake ([Formula: see text]), percentage of maximal [Formula: see text] (%[Formula: see text]), heart rate (HR), percentage of maximal HR (%HR max ) and ratings of perceived exertion (RPE) were collected during HIIE. Enjoyment was measured using the physical activity enjoyment scale (PACES) following HIIE and CMIE. Boys elicited higher absolute [Formula: see text] during HIIE work (p < .01, effect size (ES) > 1.22) and recovery (p < .02, ES > 0.51) intervals but lower %[Formula: see text] during HIIE recovery intervals compared to girls (p < .01, ES > 0.67). No sex differences in HR and %HR max were evident during HIIE and 48 participants attained ≥90% HR max . Boys produced higher RPE at intervals 6 (p = .004, ES = 1.00) and 8 (p = .003, ES = 1.00) during HIIE. PACES was higher after HIIE compared with CMIE (p = .003, ES = 0.58). Items from PACES "I got something out of it", "It's very exciting" and "It gives me a strong feeling of success" were higher after HIIE (all p < .01, ES > 0.32). The items "I feel bored" and "It's not at all interesting" were higher after CMIE (all p < .01, ES > 0.46). HIIE elicits a maximal cardiorespiratory response in most adolescents. Greater enjoyment after HIIE was due to elevated feelings of reward, excitement and success and may serve as a strategy to promote health in youth.

Carbohydrate Dependence During Prolonged, Intense Endurance Exercise.

PubMed

Hawley, John A; Leckey, Jill J

2015-11-01

A major goal of training to improve the performance of prolonged, continuous, endurance events lasting up to 3 h is to promote a range of physiological and metabolic adaptations that permit an athlete to work at both higher absolute and relative power outputs/speeds and delay the onset of fatigue (i.e., a decline in exercise intensity). To meet these goals, competitive endurance athletes undertake a prodigious volume of training, with a large proportion performed at intensities that are close to or faster than race pace and highly dependent on carbohydrate (CHO)-based fuels to sustain rates of muscle energy production [i.e., match rates of adenosine triphosphate (ATP) hydrolysis with rates of resynthesis]. Consequently, to sustain muscle energy reserves and meet the daily demands of training sessions, competitive athletes freely select CHO-rich diets. Despite renewed interest in high-fat, low-CHO diets for endurance sport, fat-rich diets do not improve training capacity or performance, but directly impair rates of muscle glycogenolysis and energy flux, limiting high-intensity ATP production. When highly trained athletes compete in endurance events lasting up to 3 h, CHO-, not fat-based fuels are the predominant fuel for the working muscles and CHO, not fat, availability becomes rate limiting for performance.

Very Low Volume Sprint Interval Exercise Suppresses Subjective Appetite, Lowers Acylated Ghrelin, and Elevates GLP-1 in Overweight Individuals: A Pilot Study.

PubMed

Holliday, Adrian; Blannin, Andrew K

2017-04-05

High-intensity exercise has been shown to elicit a transient suppression of appetite and create a more anorexigenic profile of appetite-associated hormones. It is yet to be fully elucidated whether such a response is observed following very low-volume, intermittent exercise at supramaximal intensity in those who are overweight. Eight overweight individuals (BMI 27.7 ± 1.7 kg·m²) completed resting (REST) and exercise (EX) trials in a counterbalanced order. EX consisted of 4 × 30 s "flat-out" cycling on an ergometer (adapted Wingate test). Two hours post-exercise (or REST), participants were presented with an ad libitum meal. Subjective appetite measures and blood samples were obtained throughout. Subjective appetite, measured using VAS, was significantly lower immediately after exercise compared with REST (38.0 ± 28.5 mm vs. 75.1 ± 26.2 mm, p = 0.018, d = 1.09). This difference remained significant 30 min post-exercise. Acylated ghrelin concentration was suppressed in EX compared with REST immediately post-exercise (113.4 ± 43.0 pg·mL -1 vs. 189.2 ± 91.8 pg·mL -1 , p = 0.03, d = 1.07) and remained lower until the ad libitum test-meal. Area-under-the-curve for GLP-1 concentration was significantly greater for EX, versus REST. There was no difference in absolute ad libitum intake or relative energy intake. As little as 4 × 30 s of "flat-out" cycling was sufficient to elicit a transient suppression of appetite and an enduring suppression of plasma acylated ghrelin. Nonetheless, food intake 2-h post-exercise was unaffected.

Very Low Volume Sprint Interval Exercise Suppresses Subjective Appetite, Lowers Acylated Ghrelin, and Elevates GLP-1 in Overweight Individuals: A Pilot Study

PubMed Central

Holliday, Adrian; Blannin, Andrew K.

2017-01-01

High-intensity exercise has been shown to elicit a transient suppression of appetite and create a more anorexigenic profile of appetite-associated hormones. It is yet to be fully elucidated whether such a response is observed following very low-volume, intermittent exercise at supramaximal intensity in those who are overweight. Eight overweight individuals (BMI 27.7 ± 1.7 kg·m2) completed resting (REST) and exercise (EX) trials in a counterbalanced order. EX consisted of 4 × 30 s “flat-out” cycling on an ergometer (adapted Wingate test). Two hours post-exercise (or REST), participants were presented with an ad libitum meal. Subjective appetite measures and blood samples were obtained throughout. Subjective appetite, measured using VAS, was significantly lower immediately after exercise compared with REST (38.0 ± 28.5 mm vs. 75.1 ± 26.2 mm, p = 0.018, d = 1.09). This difference remained significant 30 min post-exercise. Acylated ghrelin concentration was suppressed in EX compared with REST immediately post-exercise (113.4 ± 43.0 pg·mL−1 vs. 189.2 ± 91.8 pg·mL−1, p = 0.03, d = 1.07) and remained lower until the ad libitum test-meal. Area-under-the-curve for GLP-1 concentration was significantly greater for EX, versus REST. There was no difference in absolute ad libitum intake or relative energy intake. As little as 4 × 30 s of “flat-out” cycling was sufficient to elicit a transient suppression of appetite and an enduring suppression of plasma acylated ghrelin. Nonetheless, food intake 2-h post-exercise was unaffected. PMID:28379172

Influence of running stride frequency in heart rate variability analysis during treadmill exercise testing.

PubMed

Bailón, Raquel; Garatachea, Nuria; de la Iglesia, Ignacio; Casajús, Jose Antonio; Laguna, Pablo

2013-07-01

The analysis and interpretation of heart rate variability (HRV) during exercise is challenging not only because of the nonstationary nature of exercise, the time-varying mean heart rate, and the fact that respiratory frequency exceeds 0.4 Hz, but there are also other factors, such as the component centered at the pedaling frequency observed in maximal cycling tests, which may confuse the interpretation of HRV analysis. The objectives of this study are to test the hypothesis that a component centered at the running stride frequency (SF) appears in the HRV of subjects during maximal treadmill exercise testing, and to study its influence in the interpretation of the low-frequency (LF) and high-frequency (HF) components of HRV during exercise. The HRV of 23 subjects during maximal treadmill exercise testing is analyzed. The instantaneous power of different HRV components is computed from the smoothed pseudo-Wigner-Ville distribution of the modulating signal assumed to carry information from the autonomic nervous system, which is estimated based on the time-varying integral pulse frequency modulation model. Besides the LF and HF components, the appearance is revealed of a component centered at the running SF as well as its aliases. The power associated with the SF component and its aliases represents 22±7% (median±median absolute deviation) of the total HRV power in all the subjects. Normalized LF power decreases as the exercise intensity increases, while normalized HF power increases. The power associated with the SF does not change significantly with exercise intensity. Consideration of the running SF component and its aliases is very important in HRV analysis since stride frequency aliases may overlap with LF and HF components.

31P magnetization transfer measurements of Pi→ATP flux in exercising human muscle

PubMed Central

Savage, David B.; Williams, Guy B.; Porter, David; Carpenter, T. Adrian; Brindle, Kevin M.; Kemp, Graham J.

2016-01-01

Fundamental criticisms have been made over the use of 31P magnetic resonance spectroscopy (MRS) magnetization transfer estimates of inorganic phosphate (Pi)→ATP flux (VPi-ATP) in human resting skeletal muscle for assessing mitochondrial function. Although the discrepancy in the magnitude of VPi-ATP is now acknowledged, little is known about its metabolic determinants. Here we use a novel protocol to measure VPi-ATP in human exercising muscle for the first time. Steady-state VPi-ATP was measured at rest and over a range of exercise intensities and compared with suprabasal oxidative ATP synthesis rates estimated from the initial rates of postexercise phosphocreatine resynthesis (VATP). We define a surplus Pi→ATP flux as the difference between VPi-ATP and VATP. The coupled reactions catalyzed by the glycolytic enzymes GAPDH and phosphoglycerate kinase (PGK) have been shown to catalyze measurable exchange between ATP and Pi in some systems and have been suggested to be responsible for this surplus flux. Surplus VPi-ATP did not change between rest and exercise, even though the concentrations of Pi and ADP, which are substrates for GAPDH and PGK, respectively, increased as expected. However, involvement of these enzymes is suggested by correlations between absolute and surplus Pi→ATP flux, both at rest and during exercise, and the intensity of the phosphomonoester peak in the 31P NMR spectrum. This peak includes contributions from sugar phosphates in the glycolytic pathway, and changes in its intensity may indicate changes in downstream glycolytic intermediates, including 3-phosphoglycerate, which has been shown to influence the exchange between ATP and Pi catalyzed by GAPDH and PGK. PMID:26744504

31P magnetization transfer measurements of Pi→ATP flux in exercising human muscle.

PubMed

Sleigh, Alison; Savage, David B; Williams, Guy B; Porter, David; Carpenter, T Adrian; Brindle, Kevin M; Kemp, Graham J

2016-03-15

Fundamental criticisms have been made over the use of (31)P magnetic resonance spectroscopy (MRS) magnetization transfer estimates of inorganic phosphate (Pi)→ATP flux (VPi-ATP) in human resting skeletal muscle for assessing mitochondrial function. Although the discrepancy in the magnitude of VPi-ATP is now acknowledged, little is known about its metabolic determinants. Here we use a novel protocol to measure VPi-ATP in human exercising muscle for the first time. Steady-state VPi-ATP was measured at rest and over a range of exercise intensities and compared with suprabasal oxidative ATP synthesis rates estimated from the initial rates of postexercise phosphocreatine resynthesis (VATP). We define a surplus Pi→ATP flux as the difference between VPi-ATP and VATP. The coupled reactions catalyzed by the glycolytic enzymes GAPDH and phosphoglycerate kinase (PGK) have been shown to catalyze measurable exchange between ATP and Pi in some systems and have been suggested to be responsible for this surplus flux. Surplus VPi-ATP did not change between rest and exercise, even though the concentrations of Pi and ADP, which are substrates for GAPDH and PGK, respectively, increased as expected. However, involvement of these enzymes is suggested by correlations between absolute and surplus Pi→ATP flux, both at rest and during exercise, and the intensity of the phosphomonoester peak in the (31)P NMR spectrum. This peak includes contributions from sugar phosphates in the glycolytic pathway, and changes in its intensity may indicate changes in downstream glycolytic intermediates, including 3-phosphoglycerate, which has been shown to influence the exchange between ATP and Pi catalyzed by GAPDH and PGK. Copyright © 2016 the American Physiological Society.

The cardiovascular and metabolic responses to Wii Fit video game playing in middle-aged and older adults.

PubMed

Guderian, B; Borreson, L A; Sletten, L E; Cable, K; Stecker, T P; Probst, M A; Dalleck, L C

2010-12-01

The purpose of this study was (a) to assess the cardiovascular and metabolic responses to Wii Fit video games and (b) to determine if Wii Fit video games meet the American College of Sports Medicine guidelines for improving and maintaining cardiorespiratory fitness. Twenty men and women (mean±SD age, height, and weight: = 58.1±8.8 years, 172.1±10.5 cm, 87.1±22.8 kg, respectively) completed a 20-min Wii Fit testing session consisting of six separate aerobic and balance games. Cardiovascular and metabolic data were collected via a portable calorimetric measurement system. Mean relative exercise intensity was 43.4±16.7% of heart rate reserve. Absolute exercise intensity in metabolic equivalents (METS) was 3.5±0.96. Total net energy expenditure for the Wii Fit video game playing session was 116.2±40.9 kcal/session. Results indicate that playing Wii Fit video games is a feasible alternative to more traditional aerobic exercise modalities for middle-aged and older adults that fulfills the American College of Sports Medicine guidelines for improving and maintaining cardiorespiratory fitness.

Exercise volume and aerobic fitness in young adults: the Midwest Exercise Trial-2.

PubMed

Schubert, Matthew M; Washburn, Richard A; Honas, Jeffery J; Lee, Jaehoon; Donnelly, Joseph E

2016-01-01

To examine the effect of exercise volume at a fixed intensity on changes in aerobic fitness. Ninety-two overweight/obese individuals (BMI 25-40 kg m(2)), age 18-30 years, 50 % women, completed a 10 mo, 5 d wk(-1) supervised exercise intervention at 2 levels of exercise energy expenditure (400 or 600 kcal session(-1)) at 70-80 % heart rate (HR) max. Exercise consisted primarily of walking/jogging on motor-driven treadmills. The duration and intensity of all exercise sessions were verified by a downloadable HR monitor set to collect HR in 1-min epochs. All participants were instructed to continue their typical patterns of non-exercise physical activity and dietary intake over the duration of the 10 mo intervention. Maximal aerobic capacity (indirect calorimetry) was assessed on a motor-driven treadmill using a modified Balke protocol at baseline, mid-point (5 mo), and following completion of the 10 mo intervention. VO2 max (L min(-1)) increased significantly in both the 400 (11.3 %) and 600 kcal session(-1) groups (14 %) compared to control (-2.0 %; p < 0.001); however, the differences between exercise groups were not significant. Similar results were noted for change in relative VO2 max (mL kg(-1) min(-1)); however, the magnitude of change was greater than for absolute VO2 max (L min(-1)) (400 group = 18.3 %; 600 group = 20.2 %) due to loss of body weight over the 10-mo intervention in both exercise groups. Our results indicate that exercise volume was not associated with change in aerobic fitness in a sample of previously sedentary, overweight and obese young adults.

Effects of two kinds of underwear on metabolic heat production during 60 min recovery after 30 min severe exercise in the cold.

PubMed

Ha, M; Tokura, H; Gotoh, J; Holmér, I

1998-09-01

The purpose of this study is to investigate the thermophysiological significance of hydrophilic and hydrophobic properties of underwear materials under the influences of profuse sweating produced during severe exercise in the cold. Two kinds of underwear were used: two layers of cotton underwear with two-piece long-sleeved shirt and full-trousers (C), and two layers of polypropylene underwear with two-piece long-sleeved shirt and full-trousers (P). In addition, the subject put on a two-piece ski suit of 100% polyester including 100% polyester padding. Eight adult females volunteered as subjects in this study. The test was performed in a climatic chamber at an ambient air temperature of 2 degrees C and an air velocity of 0.26 m.s-1. The subject exercised on a cycle ergometer at an intensity of 65% maximal oxygen uptake for 30 min and followed by 60 min recovery. The major findings are summarized as follows: 1) The fall of rectal temperature tended to be greater in P during the recovery. 2) The absolute humidity of innermost layer and middle layer was significantly higher in C than in P during the recovery, but the absolute humidity of middle layer and outermost layer was significantly higher in P than in C during the exercise. 3) Clothing microclimate temperature of innermost at back was significantly higher in C during the exercise and recovery. 4) Metabolic heat production for last 30 min during recovery was significantly higher in P. 5) The degree of skin wettedness sensation and sweating sensation for whole body was significantly higher in P during the exercise. It was concluded that the slower evaporation behavior by absorbing of underwear material in the clothing system has a beneficial influence on thermophysiological responses during severe exercise and its recovery in the cold, although the differences were very small.

Accuracy of continuous glucose monitoring during exercise in type 1 diabetes pregnancy.

PubMed

Kumareswaran, Kavita; Elleri, Daniela; Allen, Janet M; Caldwell, Karen; Nodale, Marianna; Wilinska, Malgorzata E; Amiel, Stephanie A; Hovorka, Roman; Murphy, Helen R

2013-03-01

Performance of continuous glucose monitors (CGMs) may be lower when glucose levels are changing rapidly, such as occurs during physical activity. Our aim was to evaluate accuracy of a current-generation CGM during moderate-intensity exercise in type 1 diabetes (T1D) pregnancy. As part of a study of 24-h closed-loop insulin delivery in 12 women with T1D (disease duration, 17.6 years; glycosylated hemoglobin, 6.4%) during pregnancy (gestation, 21 weeks), we evaluated the Freestyle Navigator(®) sensor (Abbott Diabetes Care, Alameda, CA) during afternoon (15:00-18:00 h) and morning (09:30-12:30 h) exercise (55 min of brisk walking on a treadmill followed by a 2-h recovery), compared with sedentary conditions (18:00-09:00 h). Plasma (reference) glucose, measured at regular 15-30-min intervals with the YSI Ltd. (Fleet, United Kingdom) model YSI 2300 analyzer, was used to assess CGM performance. Sensor accuracy, as indicated by the larger relative absolute difference (RAD) between paired sensor and reference glucose values, was lower during exercise compared with rest (median RAD, 11.8% vs. 18.4%; P<0.001). These differences remained significant when correcting for plasma glucose relative rate of change (P<0.001). Analysis by glucose range showed lower accuracy during hypoglycemia for both sedentary (median RAD, 24.4%) and exercise (median RAD, 32.1%) conditions. Using Clarke error grid analysis, 96% of CGM values were clinically safe under resting conditions compared with only 87% during exercise. Compared with sedentary conditions, accuracy of the Freestyle Navigator CGM was lower during moderate-intensity exercise in pregnant women with T1D. This difference was particularly marked in hypoglycemia and could not be solely explained by the glucose rate of change associated with physical activity.

Effects of Long-Term Exercise Interventions on Glycaemic Control in Type 1 and Type 2 Diabetes: a Systematic Review.

PubMed

Röhling, M; Herder, C; Roden, M; Stemper, T; Müssig, K

2016-09-01

Aim: Physical activity is one of the cornerstones in the prevention and management of diabetes mellitus, but the effects of different training forms on metabolic control still remain unclear. The aims of this review are to summarize the recommendations of 5 selected diabetes associations and to systematically review the effects of long-term supervised exercise interventions without calorie-restriction on glycemic control in people with type 1 and 2 diabetes focusing on resistance, endurance and combined training consisting of both endurance and resistance training. Methods: Literature searches were performed using MEDLINE for articles published between January 1, 2000 and March 17, 2015. Of 76 articles retrieved, 15 randomized and controlled studies met the inclusion criteria and allowed for examining the effect of exercise training in type 1 and 2 diabetes. Results: Diabetes associations recommend volume-focused exercise in their guidelines. In our analysis, all 3 training forms have the potential to improve the glycemic control, as assessed by HbA 1c (absolute changes in HbA 1c ranging from -0.1% to -1.1% (-1.1 to -12 mmol/mol) in resistance training, from -0.2% to -1.6% (-2.2 to -17.5 mmol/mol) in endurance training and from +0.1% to -1.5% (+1.1 to -16.4 mmol/mol) in combined training, respectively). Conclusions: There is evidence that combined exercise training may improve glycemic control to a greater extent than single forms of exercise, especially under moderate-intensive training conditions with equal training durations. In addition, intensity of training appears to be an important determinant of the degree of metabolic improvement. Nonetheless, it is still unknown to what extent exercise effects glycemic homeostasis. © Georg Thieme Verlag KG Stuttgart · New York.

One session of high-intensity interval training (HIIT) every 5 days, improves muscle power but not static balance in lifelong sedentary ageing men

PubMed Central

Sculthorpe, Nicholas F.; Herbert, Peter; Grace, Fergal

2017-01-01

Abstract Background: Declining muscle power during advancing age predicts falls and loss of independence. High-intensity interval training (HIIT) may improve muscle power, but remains largely unstudied in ageing participants. Methods: This randomized controlled trial (RCT) investigated the efficacy of a low-frequency HIIT (LfHIIT) intervention on peak muscle power (peak power output [PPO]), body composition, and balance in lifelong sedentary but otherwise healthy males. Methods: Thirty-three lifelong sedentary ageing men were randomly assigned to either intervention (INT; n = 22, age 62.3 ± 4.1 years) or control (n = 11, age 61.6 ± 5.0 years) who were both assessed at 3 distinct measurement points (phase A), after 6 weeks of conditioning exercise (phase B), and after 6 weeks of HIIT once every 5 days in INT (phase C), where control remained inactive throughout the study. Results: Static balance remained unaffected, and both absolute and relative PPO were not different between groups at phases A or B, but increased significantly in INT after LfHIIT (P < 0.01). Lean body mass displayed a significant interaction (P < 0.01) due to an increase in INT between phases B and C (P < 0.05). Conclusions: 6 weeks of LfHIIT exercise feasible and effective method to induce clinically relevant improvements in absolute and relative PPO, but does not improve static balance in sedentary ageing men. PMID:28178145

One session of high-intensity interval training (HIIT) every 5 days, improves muscle power but not static balance in lifelong sedentary ageing men: A randomized controlled trial.

PubMed

Sculthorpe, Nicholas F; Herbert, Peter; Grace, Fergal

2017-02-01

Declining muscle power during advancing age predicts falls and loss of independence. High-intensity interval training (HIIT) may improve muscle power, but remains largely unstudied in ageing participants. This randomized controlled trial (RCT) investigated the efficacy of a low-frequency HIIT (LfHIIT) intervention on peak muscle power (peak power output [PPO]), body composition, and balance in lifelong sedentary but otherwise healthy males. Thirty-three lifelong sedentary ageing men were randomly assigned to either intervention (INT; n = 22, age 62.3 ± 4.1 years) or control (n = 11, age 61.6 ± 5.0 years) who were both assessed at 3 distinct measurement points (phase A), after 6 weeks of conditioning exercise (phase B), and after 6 weeks of HIIT once every 5 days in INT (phase C), where control remained inactive throughout the study. Static balance remained unaffected, and both absolute and relative PPO were not different between groups at phases A or B, but increased significantly in INT after LfHIIT (P < 0.01). Lean body mass displayed a significant interaction (P < 0.01) due to an increase in INT between phases B and C (P < 0.05). 6 weeks of LfHIIT exercise feasible and effective method to induce clinically relevant improvements in absolute and relative PPO, but does not improve static balance in sedentary ageing men.

Physical activity improves cognition: possible explanations.

PubMed

Koščak Tivadar, Blanka

2017-08-01

Good cognitive abilities (CA) enable autonomy, improve social inclusion and act preventively. Regular physical activity (PA) reduces the risk of developing Alzheimer's disease (AD) and, at the same time, it reduces the decline of CA and stimulates neurogenesis. So PA in connection with cognitive training, nutrition and social interaction has a positive effect on general CA and the central nervous system, the central executor, memory and attention, and reduces the likelihood of developing dementia. Our objective was to examine which sort and intensity of PA is preferred. We did a review, restricted only to human studies, of transparent scientific articles and sample surveys carried out and published in the period between 2001 and 2016 based on the keywords: age, aging, physical activity, physical abilities, cognitive abilities, memory and Alzheimer's disease. According to results CA and PA interact, as an increasing PA of only 10% reduces the risk of dementia and AD significantly. However, there is a question of appropriate intensity of exercise. Low-intensity aerobic exercise has a positive effect on the visual spatial perception and attention, whereas moderate PA has a positive impact on general CA, working memory and attention, verbal memory and attention and vice versa. While the majority of experts recommends vigorous or moderate exercise, many of them warn that higher intensity requires more attention to PA and less to cognitive processes, particularly in terms of reducing reactions, selective attention and flexibility to tasks. There is also a further question what PA should be like. Although some experts believe that the best combination is aerobic PA and exercises against resistance, it is not entirely clear whether the improvement in CA is a result of cardiac vascular fitness. On the other hand, for most elderly it is more suitable to perform an alternative form (not anaerobic) of PA due to comorbidity and actual fragility. We can conclude that PA has a positive effect on CA, but an appropriate intensity and the type of exercise remain unsolved. For the relevant findings it is absolutely necessary to have an interdisciplinary approach.

Exercise in space: the European Space Agency approach to in-flight exercise countermeasures for long-duration missions on ISS.

PubMed

Petersen, Nora; Jaekel, Patrick; Rosenberger, Andre; Weber, Tobias; Scott, Jonathan; Castrucci, Filippo; Lambrecht, Gunda; Ploutz-Snyder, Lori; Damann, Volker; Kozlovskaya, Inessa; Mester, Joachim

2016-01-01

To counteract microgravity (µG)-induced adaptation, European Space Agency (ESA) astronauts on long-duration missions (LDMs) to the International Space Station (ISS) perform a daily physical exercise countermeasure program. Since the first ESA crewmember completed an LDM in 2006, the ESA countermeasure program has strived to provide efficient protection against decreases in body mass, muscle strength, bone mass, and aerobic capacity within the operational constraints of the ISS environment and the changing availability of on-board exercise devices. The purpose of this paper is to provide a description of ESA's individualised approach to in-flight exercise countermeasures and an up-to-date picture of how exercise is used to counteract physiological changes resulting from µG-induced adaptation. Changes in the absolute workload for resistive exercise, treadmill running and cycle ergometry throughout ESA's eight LDMs are also presented, and aspects of pre-flight physical preparation and post-flight reconditioning outlined. With the introduction of the advanced resistive exercise device (ARED) in 2009, the relative contribution of resistance exercise to total in-flight exercise increased (33-46 %), whilst treadmill running (42-33 %) and cycle ergometry (26-20 %) decreased. All eight ESA crewmembers increased their in-flight absolute workload during their LDMs for resistance exercise and treadmill running (running speed and vertical loading through the harness), while cycle ergometer workload was unchanged across missions. Increased or unchanged absolute exercise workloads in-flight would appear contradictory to typical post-flight reductions in muscle mass and strength, and cardiovascular capacity following LDMs. However, increased absolute in-flight workloads are not directly linked to changes in exercise capacity as they likely also reflect the planned, conservative loading early in the mission to allow adaption to µG exercise, including personal comfort issues with novel exercise hardware (e.g. the treadmill harness). Inconsistency in hardware and individualised support concepts across time limit the comparability of results from different crewmembers, and questions regarding the difference between cycling and running in µG versus identical exercise here on Earth, and other factors that might influence in-flight exercise performance, still require further investigation.

Estimating Accuracy at Exercise Intensities: A Comparative Study of Self-Monitoring Heart Rate and Physical Activity Wearable Devices

PubMed Central

Dooley, Erin E; Golaszewski, Natalie M

2017-01-01

Background Physical activity tracking wearable devices have emerged as an increasingly popular method for consumers to assess their daily activity and calories expended. However, whether these wearable devices are valid at different levels of exercise intensity is unknown. Objective The objective of this study was to examine heart rate (HR) and energy expenditure (EE) validity of 3 popular wrist-worn activity monitors at different exercise intensities. Methods A total of 62 participants (females: 58%, 36/62; nonwhite: 47% [13/62 Hispanic, 8/62 Asian, 7/62 black/ African American, 1/62 other]) wore the Apple Watch, Fitbit Charge HR, and Garmin Forerunner 225. Validity was assessed using 2 criterion devices: HR chest strap and a metabolic cart. Participants completed a 10-minute seated baseline assessment; separate 4-minute stages of light-, moderate-, and vigorous-intensity treadmill exercises; and a 10-minute seated recovery period. Data from devices were compared with each criterion via two-way repeated-measures analysis of variance and Bland-Altman analysis. Differences are expressed in mean absolute percentage error (MAPE). Results For the Apple Watch, HR MAPE was between 1.14% and 6.70%. HR was not significantly different at the start (P=.78), during baseline (P=.76), or vigorous intensity (P=.84); lower HR readings were measured during light intensity (P=.03), moderate intensity (P=.001), and recovery (P=.004). EE MAPE was between 14.07% and 210.84%. The device measured higher EE at all stages (P<.01). For the Fitbit device, the HR MAPE was between 2.38% and 16.99%. HR was not significantly different at the start (P=.67) or during moderate intensity (P=.34); lower HR readings were measured during baseline, vigorous intensity, and recovery (P<.001) and higher HR during light intensity (P<.001). EE MAPE was between 16.85% and 84.98%. The device measured higher EE at baseline (P=.003), light intensity (P<.001), and moderate intensity (P=.001). EE was not significantly different at vigorous (P=.70) or recovery (P=.10). For Garmin Forerunner 225, HR MAPE was between 7.87% and 24.38%. HR was not significantly different at vigorous intensity (P=.35). The device measured higher HR readings at start, baseline, light intensity, moderate intensity (P<.001), and recovery (P=.04). EE MAPE was between 30.77% and 155.05%. The device measured higher EE at all stages (P<.001). Conclusions This study provides one of the first validation assessments for the Fitbit Charge HR, Apple Watch, and Garmin Forerunner 225. An advantage and novel approach of the study is the examination of HR and EE at specific physical activity intensities. Establishing validity of wearable devices is of particular interest as these devices are being used in weight loss interventions and could impact findings. Future research should investigate why differences between exercise intensities and the devices exist. PMID:28302596

High Intensity Exercise Countermeasures does not Prevent Orthostatic Intolerance Following Prolonged Bed Rest

NASA Technical Reports Server (NTRS)

Platts, Steven H.; Stenger, Michael B.; Ploutz-Snyder, Lori L.; Lee, Stuart M. C.

2014-01-01

Approximately 20% of Space Shuttle astronauts became presyncopal during operational stand and 80deg head-up tilt tests, and the prevalence of orthostatic intolerance increases after longer missions. Greater than 60% of the US astronauts participating in Mir and early International Space Station missions experienced presyncope during post-flight tilt tests, perhaps related to limitations of the exercise hardware that prevented high intensity exercise training until later ISS missions. The objective of this study was to determine whether an intense resistive and aerobic exercise countermeasure program designed to prevent cardiovascular and musculoskeletal deconditioning during 70 d of bed rest (BR), a space flight analog, would protect against post-BR orthostatic intolerance. METHODS Twenty-six subjects were randomly assigned to one of three groups: non-exercise controls (n=11) or one of two exercise groups (ExA, n=8; ExB, n=7). Both ExA and ExB groups performed the same resistive and aerobic exercise countermeasures during BR, but one exercise group received testosterone supplementation while the other received a placebo during BR in a double-blinded fashion. On 3 d/wk, subjects performed lower body resistive exercise and 30 min of continuous aerobic exercise (=75% max heart rate). On the other 3 d/wk, subjects performed only highintensity, interval-style aerobic exercise. Orthostatic intolerance was assessed using a 15-min 80? head-up tilt test performed 2 d (BR-2) before and on the last day of BR (BR70). Plasma volume was measured using carbon monoxide rebreathing on BR-3 and before rising on the first recovery day (BR+0). The code for the exercise groups has not been broken, and results are reported here without group identification. RESULTS Only one subject became presyncopal during tilt testing on BR-2, but 7 of 11 (63%) controls, 3 of 8 (38%) ExA, and 4 of 7 (57%) ExB subjects were presyncopal on BR70. Survival analysis of post-BR tilt tests revealed no differences (p=0.77) between groups. Plasma volume (absolute or relative to body mass index) decreased (p<0.001) from pre to post-BR, with no differences between groups. CONCLUSIONS These preliminary results corroborate previous reports that the performance of a vigorous exercise countermeasure protocol during BR, even with testosterone supplementation, does not protect against orthostatic intolerance or plasma volume loss. Preventing post-BR orthostatic intolerance may require additional countermeasures, such as orthostatic stress during BR or end-of-BR fluid infusion.

Continuous moderate-intensity exercise with or without intermittent high-intensity work: effects on acute and late glycaemia in athletes with Type 1 diabetes mellitus.

PubMed

Iscoe, K E; Riddell, M C

2011-07-01

Individuals with Type 1 diabetes mellitus are susceptible to hypoglycaemia during and after continuous moderate-intensity exercise, but hyperglycaemia during intermittent high-intensity exercise. The combination of both forms of exercise may have a moderating effect on glycaemia in recovery. The aims of this study were to compare the physiological responses and associated glycaemic changes to continuous moderate-intensity exercise vs. continuous moderate-intensity exercise + intermittent high-intensity exercise in athletes with Type 1 diabetes. Interstitial glucose levels were measured in a blinded fashion in 11 trained athletes with Type 1 diabetes during two sedentary days and during 2 days in which 45 min of afternoon continuous moderate-intensity exercise occurred either with or without intermittent high-intensity exercise. The total amount of work performed and the duration of exercise was identical between sessions. During exercise, heart rate, respiratory exchange ratio, oxygen utilization, ventilation and blood lactate levels were higher during continuous moderate-intensity + intermittent high-intensity exercise vs. continuous moderate-intensity exercise (all P < 0.05). Despite these marked cardiorespiratory differences between trials, there was no difference in the reduction of interstitial glucose or plasma glucose levels between the exercise trials. Nocturnal glucose levels were higher in continuous moderate-intensity + intermittent high-intensity exercise and in sedentary vs. continuous moderate-intensity exercise (P < 0.05). Compared with continuous moderate-intensity exercise alone, continuous moderate-intensity + intermittent high-intensity exercise was associated with less post-exercise hypoglycaemia (5.2 vs. 1.5% of the time spent with glucose < 4.0 mmol/l) and more post-exercise hyperglycaemia (33.8 vs. 20.4% of time > 11.0 mmol/l). Although the decreases in glucose level during continuous moderate-intensity exercise and continuous moderate-intensity + intermittent high-intensity exercise are similar, the latter form of exercise protects against nocturnal hypoglycaemia in athletes with Type 1 diabetes. © 2011 The Authors. Diabetic Medicine © 2011 Diabetes UK.

Immunomodulatory effect of ganoderma lucidum polysaccharides (GLP) on long-term heavy-load exercising mice.

PubMed

Shi, Yali; Cai, Dehua; Wang, Xiaojie; Liu, Xinshen

2012-12-01

Long-term heavy-load exercise can lead to a decrease in the organism's immune response. In this study, we used 100 Kunming (KM) mice to investigate the immune-regulatory effects of Ganoderma lucidum polysaccharides (GLP) on long-term heavy-load exercising mice. Peripheral white blood cells (WBC), the absolute value of neutrophils (NEUT), the phagocytic function of macrophages, serum agglutination valence, and the number of plaque-forming cells (PFC) were evaluated 4 weeks after gavaging long-term heavy-load exercising mice with GLP. After exercise, the WBC count in peripheral blood, absolute neutrophil count, macrophage phagocytic index, serum agglutination valence, and the number of plaque-forming cells were significantly reduced in the mice not fed GLP. Both medium and high doses of GLP drastically increased peripheral WBC, absolute neutrophil count, macrophage phagocytic index, serum agglutination valence, and the number of plaque-forming cells in long-term heavy-load exercising mice. High doses of GLP increased peritoneal macrophage phagocytic rate considerably. With this study, we demonstrate that 4 weeks of heavy-load exercise can lead to exercise-induced immunosuppression in mice. A supplement of GLP fed to these mice improves both non-specific and specific immune responses among these mice. The effect for the high-dose GLP treatment is especially significant.

TROIKA: a general framework for heart rate monitoring using wrist-type photoplethysmographic signals during intensive physical exercise.

PubMed

Zhang, Zhilin; Pi, Zhouyue; Liu, Benyuan

2015-02-01

Heart rate monitoring using wrist-type photoplethysmographic signals during subjects' intensive exercise is a difficult problem, since the signals are contaminated by extremely strong motion artifacts caused by subjects' hand movements. So far few works have studied this problem. In this study, a general framework, termed TROIKA, is proposed, which consists of signal decomposiTion for denoising, sparse signal RecOnstructIon for high-resolution spectrum estimation, and spectral peaK trAcking with verification. The TROIKA framework has high estimation accuracy and is robust to strong motion artifacts. Many variants can be straightforwardly derived from this framework. Experimental results on datasets recorded from 12 subjects during fast running at the peak speed of 15 km/h showed that the average absolute error of heart rate estimation was 2.34 beat per minute, and the Pearson correlation between the estimates and the ground truth of heart rate was 0.992. This framework is of great values to wearable devices such as smartwatches which use PPG signals to monitor heart rate for fitness.

Responses of catecholestrogen metabolism to acute graded exercise in normal menstruating women before and after training.

PubMed

De Crée, C; Ball, P; Seidlitz, B; Van Kranenburg, G; Geurten, P; Keizer, H A

1997-10-01

It has been hypothesized that exercise-related hypo-estrogenemia occurs as a consequence of increased competition of catecholestrogens (CE) for catechol-O-methyltransferase (COMT). This may result in higher norepinephrine (NE) concentrations, which could interfere with normal gonadotropin pulsatility. The present study investigates the effects of training on CE responses to acute exercise stress. Nine untrained eumenorrheic women (mean percentage of body fat +/-SD: 24.8 +/- 3.1%) volunteered for an intensive 5-day training program. Resting, submaximal, and maximal (tmax) exercise plasma CE, estrogen, and catecholamine responses were determined pre- and post training in both the follicular (FPh) and luteal phase (LPh). Acute exercise stress increased total primary estrogens (E) but had little effect on total 2-hydroxyestrogens (2-OHE) and 2-hydroxyestrogen-monomethylethers (2-MeOE) (= O-methylated CE after competition for catechol-O-methyltransferase). This pattern was not significantly changed by training. However, posttraining LPh mean (+/-SE) plasma E, 2-OHE, and 2-MeOE concentrations were significantly lower (P < 0.05) at each exercise intensity (for 2-OHE: 332 +/- 47 vs. 422 +/- 57 pg/mL at tmax; for 2-MeOE: 317 +/- 26 vs. 354 +/- 34 pg/mL at tmax). Training produced opposite effects on 2-OHE:E ratios (an estimation of CE formation) during acute exercise in the FPh (reduction) and LPh (increase). The 2-MeOE:2-OHE ratio (an estimation of CE activity) showed significantly higher values at tmax in both menstrual phases after training (FPh: +11%; LPh: +23%; P < 0.05). After training, NE values were significantly higher (P < 0.05). The major findings of this study were that: training lowers absolute concentrations of plasma estrogens and CE; the acute exercise challenge altered plasma estrogens but had little effect on CE; estimation of the formation and activity of CE suggests that formation and O-methylation of CE proportionately increases. These findings may be of importance for NE-mediated effects on gonadotropin release.

Effects of high-intensity interval training on physical capacities and substrate oxidation rate in obese adolescents.

PubMed

Lazzer, S; Tringali, G; Caccavale, M; De Micheli, R; Abbruzzese, L; Sartorio, A

2017-02-01

To investigate the effects of a 3-week weight-management program entailing moderate energy restriction, nutritional education, psychological counseling and three different exercise training (a: low intensity, LI: 40 % V'O 2 max; b: high intensity, HI: 70 % V'O 2 max; c: high-intensity interval training, HIIT), on body composition, energy expenditure and fat oxidation rate in obese adolescents. Thirty obese adolescents (age: 15-17 years, BMI: 37.5 kg m -2 ) participated in this study. Before starting (week 0, W0) and at the end of the weight-management program (week 3, W3), body composition was assessed by an impedancemeter; basal metabolic rate (BMR), energy expenditure and substrate oxidation rate were measured during exercise and post-exercise recovery by indirect calorimetry. At W3, body mass (BM) and fat mass (FM) decreased significantly in all groups, the decreases being significantly greater in the LI than in the HI and HIIT subgroups (BM: -8.4 ± 1.5 vs -6.3 ± 1.9 vs -4.9 ± 1.3 kg and FM: -4.2 ± 1.9 vs -2.8 ± 1.2 vs -2.3 ± 1.4 kg, p < 0.05, respectively). V'O 2 peak, expressed in relative values, changed significantly only in the HI and HIIT groups by 0.009 ± 0.005 and 0.007 ± 0.004 L kg FFM -1  min -1 (p < 0.05). Furthermore, the HI and HIIT subgroups exhibited a greater absolute rate of fat oxidation between 50 and 70 % V'O 2 peak at W3. No significant changes were observed at W3 in BMR, energy expenditure during exercise and post-exercise recovery. A 3-week weight-management program induced a greater decrease in BM and FM in the LI than in the HI and HIIT subgroups, and greater increase in V'O 2 peak and fat oxidation rate in the HI and HIIT than in the LI subgroup.

Implementing intelligent physical exercise training at the workplace: health effects among office workers-a randomized controlled trial.

PubMed

Dalager, Tina; Justesen, Just Bendix; Murray, Mike; Boyle, Eleanor; Sjøgaard, Gisela

2016-07-01

The aim was to assess 1-year cardiovascular health effects of Intelligent Physical Exercise Training, IPET. Office workers from six companies were randomized 1:1 to a training group, TG (N = 194) or a control group, CG (N = 195). TG received 1-h supervised high intensity IPET every week within working hours for 1 year, and was recommended to perform 30-min of moderate intensity physical activity 6 days a week during leisure. The training program was based on baseline health check measures of cardiorespiratory fitness (CRF), body composition, blood pressure, blood profile, and musculoskeletal health. There were no baseline differences between groups. CRF assessed as VO2max in absolute values and relative to body weight was (mean ± SD): 3.0 ± 0.8 l/min and 35.4 ± 10.9 ml/min/kg for females, 3.9 ± 1.0 l/min and 37.9 ± 11.79 ml/min/kg for males. Intention to treat analysis demonstrated a significant almost 5 % increase in VO2max in TG compared with CG. A per protocol analysis of those with an adherence of ≥70 % demonstrated a significant increase in CRF of more than 10 % compared with CG, and a significant reduction in systolic blood pressure (-5.3 ± 13.7 mm Hg) compared with CG. High intensity IPET combined with the recommendations of moderate intensity physical activity demonstrated significant clinical relevant improvements in CRF and systolic blood pressure. This underlines the effectiveness of health promotion by implementing physical exercise training at the workplace.

Estimating Accuracy at Exercise Intensities: A Comparative Study of Self-Monitoring Heart Rate and Physical Activity Wearable Devices.

PubMed

Dooley, Erin E; Golaszewski, Natalie M; Bartholomew, John B

2017-03-16

Physical activity tracking wearable devices have emerged as an increasingly popular method for consumers to assess their daily activity and calories expended. However, whether these wearable devices are valid at different levels of exercise intensity is unknown. The objective of this study was to examine heart rate (HR) and energy expenditure (EE) validity of 3 popular wrist-worn activity monitors at different exercise intensities. A total of 62 participants (females: 58%, 36/62; nonwhite: 47% [13/62 Hispanic, 8/62 Asian, 7/62 black/ African American, 1/62 other]) wore the Apple Watch, Fitbit Charge HR, and Garmin Forerunner 225. Validity was assessed using 2 criterion devices: HR chest strap and a metabolic cart. Participants completed a 10-minute seated baseline assessment; separate 4-minute stages of light-, moderate-, and vigorous-intensity treadmill exercises; and a 10-minute seated recovery period. Data from devices were compared with each criterion via two-way repeated-measures analysis of variance and Bland-Altman analysis. Differences are expressed in mean absolute percentage error (MAPE). For the Apple Watch, HR MAPE was between 1.14% and 6.70%. HR was not significantly different at the start (P=.78), during baseline (P=.76), or vigorous intensity (P=.84); lower HR readings were measured during light intensity (P=.03), moderate intensity (P=.001), and recovery (P=.004). EE MAPE was between 14.07% and 210.84%. The device measured higher EE at all stages (P<.01). For the Fitbit device, the HR MAPE was between 2.38% and 16.99%. HR was not significantly different at the start (P=.67) or during moderate intensity (P=.34); lower HR readings were measured during baseline, vigorous intensity, and recovery (P<.001) and higher HR during light intensity (P<.001). EE MAPE was between 16.85% and 84.98%. The device measured higher EE at baseline (P=.003), light intensity (P<.001), and moderate intensity (P=.001). EE was not significantly different at vigorous (P=.70) or recovery (P=.10). For Garmin Forerunner 225, HR MAPE was between 7.87% and 24.38%. HR was not significantly different at vigorous intensity (P=.35). The device measured higher HR readings at start, baseline, light intensity, moderate intensity (P<.001), and recovery (P=.04). EE MAPE was between 30.77% and 155.05%. The device measured higher EE at all stages (P<.001). This study provides one of the first validation assessments for the Fitbit Charge HR, Apple Watch, and Garmin Forerunner 225. An advantage and novel approach of the study is the examination of HR and EE at specific physical activity intensities. Establishing validity of wearable devices is of particular interest as these devices are being used in weight loss interventions and could impact findings. Future research should investigate why differences between exercise intensities and the devices exist. ©Erin E Dooley, Natalie M Golaszewski, John B Bartholomew. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 16.03.2017.

Pain Response after Maximal Aerobic Exercise in Adolescents across Weight Status

PubMed Central

Stolzman, Stacy; Danduran, Michael; Hunter, Sandra K; Bement, Marie Hoeger

2015-01-01

Introduction Pain reports are greater with increasing weight status, and exercise can reduce pain perception. It is unknown however, whether exercise can relieve pain in adolescents of varying weight status. The purpose of this study was to determine if adolescents across weight status report pain relief following high intensity aerobic exercise (exercise-induced hypoalgesia [EIH]). Methods 62 adolescents (15.1±1.8 years, 29 males) participated in three sessions: 1) Pressure pain thresholds (PPTs) before and after quiet rest, clinical pain (McGill Pain Questionnaire), and physical activity levels (self-report and ActiSleep Plus Monitors) were measured; 2) PPTs were measured with a computerized algometer at the 4th finger nailbed, middle deltoid muscle, and quadriceps muscle before and after maximal oxygen uptake test (VO2 max Bruce Treadmill Protocol); and 3) Body composition was measured with Dual-energy X-ray absorptiometry. Results All adolescents met criteria for VO2 max. Based on body mass index z-score, adolescents were categorized as normal weight (n=33) or overweight/obese (n=29). PPTs increased following exercise (EIH) and were unchanged with quiet rest (trial × session: p=0.02). EIH was similar across the 3 sites and between normal weight and overweight/obese adolescents. Physical activity and clinical pain were not correlated with EIH. Overweight/obese adolescents had similar absolute VO2 max (L·min-1) but lower relative VO2 max (ml·kg-1·min-1) compared with normal weight adolescents. When adolescents were categorized using FitnessGram standards as unfit (n=15) and fit (n=46), the EIH response was similar between fitness levels. Conclusion This study is the first to establish that adolescents experience EIH in both overweight and normal weight youth. EIH after high intensity aerobic exercise was robust in adolescents regardless of weight status and not influenced by physical fitness. PMID:25856681

Exercise-Induced Hypoalgesia After Isometric Wall Squat Exercise: A Test-Retest Reliabilty Study.

PubMed

Vaegter, Henrik Bjarke; Lyng, Kristian Damgaard; Yttereng, Fredrik Wannebo; Christensen, Mads Holst; Sørensen, Mathias Brandhøj; Graven-Nielsen, Thomas

2018-05-19

Isometric exercises decrease pressure pain sensitivity in exercising and nonexercising muscles known as exercise-induced hypoalgesia (EIH). No studies have assessed the test-retest reliability of EIH after isometric exercise. This study investigated the EIH on pressure pain thresholds (PPTs) after an isometric wall squat exercise. The relative and absolute test-retest reliability of the PPT as a test stimulus and the EIH response in exercising and nonexercising muscles were calculated. In two identical sessions, PPTs of the thigh and shoulder were assessed before and after three minutes of quiet rest and three minutes of wall squat exercise, respectively, in 35 healthy subjects. The relative test-retest reliability of PPT and EIH was determined using analysis of variance models, Person's r, and intraclass correlations (ICCs). The absolute test-retest reliability of EIH was determined based on PPT standard error of measurements and Cohen's kappa for agreement between sessions. Squat increased PPTs of exercising and nonexercising muscles by 16.8% ± 16.9% and 6.7% ± 12.9%, respectively (P < 0.001), with no significant differences between sessions. PPTs within and between sessions showed moderately strong correlations (r ≥ 0.74) and excellent (ICC ≥ 0.84) within-session (rest) and between-session test-retest reliability. EIH responses of exercising and nonexercising muscles showed no systematic errors between sessions; however, the relative test-retest reliability was low (ICCs = 0.03-0.43), and agreement in EIH responders and nonresponders between sessions was not significant (κ < 0.13, P > 0.43). A wall squat exercise increased PPTs compared with quiet rest; however, the relative and absolute reliability of the EIH response was poor. Future research is warranted to investigate the reliability of EIH in clinical pain populations.

Exercise-induced oxyhaemoglobin desaturation, ventilatory limitation and lung diffusing capacity in women during and after exercise.

PubMed

Walls, Justin; Maskrey, Michael; Wood-Baker, Richard; Stedman, Wade

2002-06-01

Arterial haemoglobin saturation during exercise in healthy young women [eight subjects mean (SEM) age 20.8 (1.8) years] was measured to confirm the theory that young women experience exercise-induced arterial hypoxaemia (EIAH) at a lower relative percentage of maximal oxygen uptake (VO(2max)) than has been documented in their male counterparts. To determine if flow limitation [the percentage of the tidal volume ( V(T)) that met or exceeded the boundary established by multiple maximal expiratory manoeuvres] and/or post-exercise lung diffusing capacity are linked to EIAH in women, and to investigate the influence of exercise intensity and duration on post-exercise carbon monoxide lung diffusing capacity ( D(L, CO)), these parameters were measured during and after three exercise tests (incremental test until exhaustion, 5 km run and 5 km run with sprint). All subjects experienced physiologically significant EIAH (a fall of more than 3% in oxygen saturation of arterial blood from levels at rest) and seven subjects experienced flow limitation during the VO(2max) protocol [mean (SD) 12.2 (8.8)% of V(T)]. Even though there was no significant relationship between aerobic capacity and the degree of flow limitation ( r=0.33, P>0.05), the flow limitation was related to absolute ventilation in the subjects studied ( r=0.82, P<0.05). There was no significant relationship between decrements in post exercise D(L, CO) and EIAH ( r=0.05, P>0.05), however there was a strong correlation between the extent of flow limitation (% of V(T)) and EIAH ( r=0.71). Significant decreases in D(L, CO) lasted for up to 16 h after each of the exercise tests ( P<0.05) and lasted for a further 8 h after the maximal test ( P<0.05). Exercise intensity was the main contributing factor to the observed decreases in post-exercise D(L, CO) with the percentage of VO(2max) attained during the various tests being significantly related to the fall in D(L, CO) for 1, 2, 3, 16 and 24 h after exercise ( P<0.05). As the appearance of flow limitation closely coincided with the appearance of EIAH, the results from the present study suggest that flow limitation is a contributing factor to EIAH in women although the exact mechanism remains unclear.

Adults with initial metabolic syndrome have altered muscle deoxygenation during incremental exercise.

PubMed

Machado, Alessandro da Costa; Barbosa, Thales Coelho; Kluser Sales, Allan Robson; de Souza, Marcio Nogueira; da Nóbrega, Antonio Claudio Lucas; Silva, Bruno Moreira

2017-02-01

Reduced aerobic power is independently associated with metabolic syndrome (MetS) incidence and prevalence in adults. This study investigated whether muscle deoxygenation (proxy of microvascular O 2 extraction) during incremental exercise is altered in MetS and associated with reduced oxygen consumption ( V˙O 2peak ). Twelve men with initial MetS (no overt diseases and medication-naive; mean ± SD, age 38 ± 7 years) and 12 healthy controls (HCs) (34 ± 7 years) completed an incremental cycling test to exhaustion, in which pulmonary ventilation and gas exchange (metabolic analyzer), as well as vastus lateralis deoxygenation (near infrared spectroscopy), were measured. Subjects with MetS, in contrast to HCs, showed lower V˙O 2peak normalized to total lean mass, similar V˙O 2 response to exercise, and earlier break point (BP) in muscle deoxygenation. Consequently, deoxygenation slope from BP to peak exercise was greater. Furthermore, absolute V˙O 2peak was positively associated with BP in correlations adjusted for total lean mass. MetS, without overt diseases, altered kinetics of muscle deoxygenation during incremental exercise, particularly at high-intensity exercise. Therefore, the balance between utilization and delivery of O 2 within skeletal muscle is impaired early in MetS natural history, which may contribute to the reduction in aerobic power. © 2017 The Obesity Society.

Investigating the Relative Exercise Intensity of Exergames in Prepubertal Children.

PubMed

McNarry, Melitta A; Mackintosh, Kelly A

2016-04-01

The literature remains equivocal as to whether exergames elicit energy expenditure (EE) commensurate with physical activity guidelines. Such discrepancies may be attributable to a reliance on absolute exercise intensities, which fail to account for differences in cardiorespiratory fitness levels. Thirty-four prepubertal children (20 boys, 14 girls; 10.8 ± 1.0 years old) completed a 30-minute exergame (two 15-minute games from "Kinect Adventures! Xbox 360" [Microsoft, Redmond, WA]) and an incremental treadmill test to determine peak oxygen uptake ( [Formula: see text]) throughout which breath-by-breath gas exchange was measured. Both games elicited moderate-intensity physical activity (5.7 ± 1.5 and 5.5 ± 1.4 metabolic equivalents [METs]), with 36 percent demonstrating a mean EE in excess of 6.0 METs, commensurate with vigorous intensity. Furthermore, boys demonstrated higher EE during both games (boys versus girls: Game 1, 6.0 ± 1.7 versus 5.2 ± 1.0 METs; Game 2, 6.0 ± 1.4 versus girls, 4.9 ± 1.2 METs; P < 0.05). Hierarchical linear regression revealed sex, maturity, and fitness to be significant predictors of EE, accounting for 24 percent of the variance: relative exergame [Formula: see text] = 24.53 + (2.12 × Sex) - (0.42 × Maturity offset) - (0.16 × Relative peak [Formula: see text]). There was no correlation between absolute [Formula: see text] during the exergames and peak [Formula: see text], but [Formula: see text] expressed as a percentage of peak [Formula: see text] was correlated with peak [Formula: see text] during both Game 1 (r = -0.62, P < 0.01) and Game 2 (r = -0.59, P < 0.01). The present findings provide further evidence that exergames can elicit EE values commensurate with national physical activity guidelines and extend our understanding of the mediators of EE. Specifically, cardiorespiratory fitness and sex must both be considered in the design and implementation of future interventions seeking to use exergames to enhance physical activity levels and/or cardiorespiratory fitness.

Muscle intracellular oxygenation during exercise: optimization for oxygen transport, metabolism, and adaptive change.

PubMed

Wagner, Peter D

2012-01-01

Exercise is the example par excellence of the body functioning as a physiological system. Conventionally we think of the O(2) transport process as a major manifestation of that system linking and integrating pulmonary, cardiovascular, hematological and skeletal muscular contributions to the task of getting O(2) from the air to the mitochondria, and this process has been well described. However, exercise invokes system responses at levels additional to those of macroscopic O(2) transport. One such set of responses appears to center on muscle intracellular PO(2), which falls dramatically from rest to exercise. At rest, it approximates 4 kPa, but during heavy endurance exercise it falls to about 0.4-0.5 kPa, an amazingly low value for a tissue absolutely dependent on the continual supply of O(2) to meet very high energy demands. One wonders why intracellular PO(2) is allowed to fall to such levels. The proposed answer, to be presented in the review, is that a low intramyocyte PO(2) is pivotal in: (a) optimizing oxygen's own physiological transport, and (b) stimulating adaptive gene expression that, after translation, enables greater exercise capacity-all the while maintaining PO(2) at levels sufficient to allow oxidative phosphorylation to operate sufficiently fast enough to support intense muscle contraction. Thus, during exercise, reductions of intracellular PO(2) to less than 1% of that in the atmosphere enables an integrated response that fundamentally and simultaneously optimizes physiological, biochemical and molecular events that support not only the exercise as it happens but the adaptive changes to increase exercise capacity over the longer term.

Acute effects of self-selected regimen of rapid body mass loss in combat sports athletes.

PubMed

Timpmann, Saima; Oöpik, Vahur; Pääsuke, Mati; Medijainen, Luule; Ereline, Jaan

2008-01-01

The purpose of the study was to assess the acute effects of the self-selected regimen of rapid body mass loss (RBML) on muscle performance and metabolic response to exercise in combat sports athletes. Seventeen male athletes (20.8 ± 1.0 years; mean ± SD) reduced their body mass by 5.1 ± 1.1% within 3 days. The RBML was achieved by a gradual reduction of energy and fluid intake and mild sauna procedures. A battery of tests was performed before (Test 1) and immediately after (Test 2) RBML. The test battery included the measurement of the peak torque of knee extensors for three different speeds, assessment of total work (Wtot) performed during a 3-min intermittent intensity knee extension exercise and measurements of blood metabolites (ammonia, lactate, glucose and urea). Absolute peak torque was lower in Test 2 compared with Test 1 at angular velocities of 1.57 rad·s(-1) (218.6 ± 40.9 vs. 234.4 ± 42.2 N·m; p = 0.013) and 3.14 rad·s(-1) (100.3 ± 27.8 vs. 111.7 ± 26.2 N·m; p = 0.008). The peak torque in relation to body mass remained unchanged for any speed. Absolute Wtot was lower in Test 2 compared with Test 1 (6359 ± 2326 vs. 7452 ± 3080 J; p = 0.003) as well as Wtot in relation to body mass (89.1 ± 29.9 vs. 98.6 ± 36.4 J·kg(-1); p = 0.034), respectively. As a result of RBML, plasma urea concentration increased from 4.9 to 5.9 mmol·l(-1) (p = 0.003). The concentration of ammonia in a post-test sample in Test 2 tended to be higher in comparison with Test 1 (80.9 ± 29.1 vs. 67.6 ± 26.5 mmol·l(-1); p = 0.082). The plasma lactate and glucose responses to exercise were similar in Test 1 and Test 2. We conclude that the self-selected regimen of RBML impairs muscle performance in 3-min intermittent intensity exercise and induces an increase in blood urea concentration in experienced male combat sports athletes. Key pointsPrevious studies have revealed a negative effect of rapid body mass loss on performance. However, there are some performance characteristics that may not change or even improve.The methods used for inducing rapid body mass loss have been prescribed by researchers and not chosen by the subjects in many previous studies. The duration of tests, which have revealed a negative impact of rapid body mass loss on performance have also been rather long (5-6 min) in previous studies.We assessed the acute effects of the self-selected regimen of rapid body mass loss on muscle performance and metabolic response to 3-min intermittent intensity exercise in experienced male combat sports athletes.The results suggest that the self-selected regimen of rapid body mass loss impairs muscle performance in 3-min intermittent intensity exercise and induces an increase in blood urea concentration. Hence, the recent changes in the rules of some events (wrestling), including shortening of the duration of a match, have not reduced the likelihood of the occurrence of a negative impact of rapid body mass loss on athletes' performance capacity.

Calorie Estimation in Adults Differing in Body Weight Class and Weight Loss Status.

PubMed

Brown, Ruth E; Canning, Karissa L; Fung, Michael; Jiandani, Dishay; Riddell, Michael C; Macpherson, Alison K; Kuk, Jennifer L

2016-03-01

Ability to accurately estimate calories is important for weight management, yet few studies have investigated whether individuals can accurately estimate calories during exercise or in a meal. The objective of this study was to determine if accuracy of estimation of moderate or vigorous exercise energy expenditure and calories in food is associated with body weight class or weight loss status. Fifty-eight adults who were either normal weight (NW) or overweight (OW), and either attempting (WL) or not attempting weight loss (noWL), exercised on a treadmill at a moderate (60% HRmax) and a vigorous intensity (75% HRmax) for 25 min. Subsequently, participants estimated the number of calories they expended through exercise and created a meal that they believed to be calorically equivalent to the exercise energy expenditure. The mean difference between estimated and measured calories in exercise and food did not differ within or between groups after moderate exercise. After vigorous exercise, OW-noWL overestimated energy expenditure by 72% and overestimated the calories in their food by 37% (P < 0.05). OW-noWL also significantly overestimated exercise energy expenditure compared with all other groups (P < 0.05) and significantly overestimated calories in food compared with both WL groups (P < 0.05). However, among all groups, there was a considerable range of overestimation and underestimation (-280 to +702 kcal), as reflected by the large and statistically significant absolute error in calorie estimation of exercise and food. There was a wide range of underestimation and overestimation of calories during exercise and in a meal. Error in calorie estimation may be greater in overweight adults who are not attempting weight loss.

Calorie Estimation in Adults Differing in Body Weight Class and Weight Loss Status

PubMed Central

Brown, Ruth E; Canning, Karissa L; Fung, Michael; Jiandani, Dishay; Riddell, Michael C; Macpherson, Alison K; Kuk, Jennifer L

2016-01-01

Purpose Ability to accurately estimate calories is important for weight management, yet few studies have investigated whether individuals can accurately estimate calories during exercise, or in a meal. The objective of this study was to determine if accuracy of estimation of moderate or vigorous exercise energy expenditure and calories in food is associated with body weight class or weight loss status. Methods Fifty-eight adults who were either normal weight (NW) or overweight (OW), and either attempting (WL) or not attempting weight loss (noWL), exercised on a treadmill at a moderate (60% HRmax) and a vigorous intensity (75% HRmax) for 25 minutes. Subsequently, participants estimated the number of calories they expended through exercise, and created a meal that they believed to be calorically equivalent to the exercise energy expenditure. Results The mean difference between estimated and measured calories in exercise and food did not differ within or between groups following moderate exercise. Following vigorous exercise, OW-noWL overestimated energy expenditure by 72%, and overestimated the calories in their food by 37% (P<0.05). OW-noWL also significantly overestimated exercise energy expenditure compared to all other groups (P<0.05), and significantly overestimated calories in food compared to both WL groups (P<0.05). However, among all groups there was a considerable range of over and underestimation (−280 kcal to +702 kcal), as reflected by the large and statistically significant absolute error in calorie estimation of exercise and food. Conclusion There was a wide range of under and overestimation of calories during exercise and in a meal. Error in calorie estimation may be greater in overweight adults who are not attempting weight loss. PMID:26469988

Effects of circuit low-intensity resistance exercise with slow movement on oxygen consumption during and after exercise.

PubMed

Mukaimoto, Takahiro; Ohno, Makoto

2012-01-01

The purpose of this study was to examine oxygen consumption (VO(2)) during and after a single bout of low-intensity resistance exercise with slow movement. Eleven healthy men performed the following three types of circuit resistance exercise on separate days: (1) low-intensity resistance exercise with slow movement: 50% of one-repetition maximum (1-RM) and 4 s each of lifting and lowering phases; (2) high-intensity resistance exercise with normal movement: 80% of 1-RM and 1 s each of lifting and lowering phases; and (3) low-intensity resistance exercise with normal movement: 50% of 1-RM and 1 s each of lifting and lowering phases. These three resistance exercise trials were performed for three sets in a circuit pattern with four exercises, and the participants performed each set until exhaustion. Oxygen consumption was monitored continuously during exercise and for 180 min after exercise. Average VO(2) throughout the exercise session was significantly higher with high- and low-intensity resistance exercise with normal movement than with low-intensity resistance exercise with slow movement (P < 0.05); however, total VO(2) was significantly greater in low-intensity resistance exercise with slow movement than in the other trials. In contrast, there were no significant differences in the total excess post-exercise oxygen consumption among the three exercise trials. The results of this study suggest that low-intensity resistance exercise with slow movement induces much greater energy expenditure than resistance exercise with normal movement of high or low intensity, and is followed by the same total excess post-exercise oxygen consumption for 180 min after exercise.

Temperature of Ingested Water during Exercise Does Not Affect Body Heat Storage.

PubMed

Lamarche, Dallon T; Meade, Robert D; McGinn, Ryan; Poirier, Martin P; Friesen, Brian J; Kenny, Glen P

2015-06-01

The objective of this study was to examine the effect of ingested water temperature on heat balance during exercise as assessed by direct calorimetry. Ten healthy males (25 ± 4 yr) cycled at 50% V˙O2peak (equivalent rate of metabolic heat production (M-W) of 523 ± 84 W) for 75 min under thermocomfortable conditions (25°C, 25% relative humidity) while consuming either hot (50°C) or cold (1.5°C) water. Four 3.2 mL·kg⁻¹ boluses of hot or cold water were consumed 5 min before and at 15, 30, and 45 min after the onset of exercise. Total heat loss (HL = evaporative heat loss (HE) ± dry heat exchange (HD)) and M-W were measured by direct and indirect calorimetry, respectively. Change in body heat content (ΔHb) was calculated as the temporal summation of M-W and HL and adjusted for changes in heat transfer from the ingested fluid (Hfluid). The absolute difference for HL (209 ± 81 kJ) was similar to the absolute difference of Hfluid (204 ± 36 kJ) between conditions (P = 0.785). Furthermore, the difference in HL was primarily explained by the corresponding changes in HE (hot: 1538 ± 393 kJ; cold: 1358 ± 330 kJ) because HD was found to be similar between conditions (P = 0.220). Consequently, no difference in ΔHb was observed between the hot (364 ± 152 kJ) and cold (363 ± 134 kJ) conditions (P = 0.971) during exercise. We show that ingestion of hot water elicits a greater HL relative to cold water ingestion during exercise. However, this response was only compensated for the heat of the ingested fluid as evidenced by similar ΔHb between conditions. Therefore, our findings indicate that relative to cold water ingestion, consuming hot water does not provide a thermoregulatory advantage. Both hot and cold water ingestion results in the same amount of heat stored during prolonged moderate-intensity exercise.

Noninvasive Sensor for Measuring Muscle Metabolism During Exercise

NASA Technical Reports Server (NTRS)

Soller, B. R.; Yang, Y.; Lee, S. M. C.; Soyemi, O. O.; Wilson, C.; Hagan, R. D.

2007-01-01

The measurement of oxygen uptake (VO2) and lactate threshold (LT) are utilized to assess changes in aerobic capacity and the efficacy of exercise countermeasures in astronauts. During extravehicular activity (EVA), real-time knowledge of VO2 and relative work intensity can be used to monitor crew activity levels and organize tasks to reduce the cumulative effects of fatigue. Currently VO2 and LT are determined with complicated measurement techniques that require sampling of expired ventilatory gases, which may not be accurate in enclosed, oxygen-rich environments such as the EVA suit. The UMMS team has developed a novel near infrared spectroscopic (NIRS) system which noninvasively, simultaneously and continuously measures muscle oxygen tension, oxygen saturation, pH (pHm), and hematocrit from a small sensor placed on the leg. This system is unique in that it allows accurate, absolute measurement of these parameters in the thigh muscle by correcting spectra for the interference from skin pigment and fat. These parameters can be used to estimate VO2 and LT. A preliminary evaluation of the system s capabilities was performed in the NASA JSC Exercise Physiology Lab.

What influences acceptability and engagement with a high intensity exercise programme for people with stroke? A qualitative descriptive study.

PubMed

Signal, Nada; McPherson, Kathryn; Lewis, Gwyn; Kayes, Nicola; Saywell, Nicola; Mudge, Suzie; Taylor, Denise

2016-10-14

Intensity refers to the amount of effort or rate of work undertaken during exercise. People receiving rehabilitation after stroke frequently do not reach the moderate to high intensity exercise recommended to maximise gains. To explore the factors that influence the acceptability of, and engagement with, a high intensity group-based exercise programme for people with stroke. This qualitative descriptive study included 14 people with stroke who had completed a 12-week, high intensity group-based exercise rehabilitation programme. Semi-structured interviews were used to explore the acceptability of high intensity exercise and the barriers and facilitators to engagement. Interviews were recorded, transcribed and analysed using qualitative content analysis. The participants found high intensity exercise rehabilitation acceptable despite describing the exercise intensity as hard and reporting post-exercise fatigue. Participants accepted the fatigue as a normal response to exercise, and it did not appear to negatively influence engagement. The ease with which an individual engaged in high intensity exercise rehabilitation appeared to be mediated by inter-related factors, including: seeing progress, sourcing motivation, working hard, the people involved and the fit with the person and their life. Participants directly related the intensity of their effort to the gains that they made. In this study, people with stroke viewed training at higher intensities as a facilitator, not a barrier, to engagement in exercise rehabilitation. The findings may challenge assumptions about the influence of exercise intensity on engagement.

Exercise effects on bone mineral density, falls, coronary risk factors, and health care costs in older women: the randomized controlled senior fitness and prevention (SEFIP) study.

PubMed

Kemmler, Wolfgang; von Stengel, Simon; Engelke, Klaus; Häberle, Lothar; Kalender, Willi A

2010-01-25

Physical exercise affects many risk factors and diseases and therefore can play a vital role in general disease prevention and treatment of elderly individuals and may reduce costs. We sought to determine whether a single exercise program affects fracture risk (bone mineral density [BMD] and falls), coronary heart disease (CHD) risk factors, and health care costs in community-dwelling elderly women. We conducted a randomized, single-blinded, controlled trial from May 1, 2005, through July 31, 2008, recruiting women 65 years or older who were living independently in the area of Erlangen-Nuremberg, Germany. In all, 246 women were randomly assigned to an 18-month exercise program (exercise group) or a wellness program (control group). The exercise group (n = 123) performed a multipurpose exercise program with special emphasis on exercise intensity; the controls (n = 123) focused on well-being with a low-intensity, low-frequency program. The main outcome measures were BMD, the number of falls, the Framingham-based 10-year CHD risk, and direct health care costs. For the 227 women who completed the 18-month study, significant exercise effects were observed for BMD of the lumbar spine (mean [95% confidence interval (CI)] percentage of change in BMD [baseline to follow-up] for the exercise group: 1.77% [1.26% to 2.28%] vs controls: 0.33% [-0.24% to 0.91%]; P < .001), femoral neck (exercise group: 1.01% [0.37% to 1.65%] vs controls: -1.05% [-1.70% to -0.40%]; P < .001), and fall rate per person during 18 months (exercise group: 1.00 [0.76 to 1.24] vs controls: 1.66 [1.33 to 1.99]; P = .002). The 10-year CHD risk was significantly affected in both subgroups (absolute change for the exercise group: -1.96% [95% CI, -2.69% to -1.23%] vs controls: -1.15% [-1.69% to -0.62%]; P = .22), with no significant difference between the groups. The direct health care costs per participant during the 18-month intervention showed nonsignificant differences between the groups (exercise group: 2255 euros[95% CI, 1791 euros-2718 euros] vs controls: 2780 euros [2187 euros-3372 euros]; P = .20). Compared with a general wellness program, our 18-month exercise program significantly improved BMD and fall risk, but not predicted CHD risk, in elderly women. This benefit occurred at no increase in direct costs. clinicaltrials.gov Identifier: NCT00267839.

Acute effects of high- and low-intensity exercise bouts on leukocyte counts.

PubMed

Neves, Pedro Rogério Da Silva; Tenório, Thiago Ricardo Dos Santos; Lins, Tatiana Acioli; Muniz, Maria Tereza Cartaxo; Pithon-Curi, Tânia Cristina; Botero, João Paulo; Do Prado, Wagner Luiz

2015-06-01

It is widely accepted that physical exercise may bring about changes in the immune system. Even acute bouts of exercise can alter the number and function of leukocytes, but the degree of white blood cell trafficking depends on the intensity and duration of exercise. The aim of this study was to analyze the acute and short-term effects of exercise intensity on leukocyte counts and leukocyte subsets. Nine physically healthy, active young males (21.0 ± 1.9 years) underwent three experimental trials: high exercise intensity [80% peak oxygen consumption (VO 2peak )], low exercise intensity (40% VO 2peak ), and the control condition (no exercise). Blood samples were collected prior to exercise, immediately after exercise, and 2 hours after exercise. Two-way analysis of variance for repeated measures was used to evaluate differences between the trials and the time-points, and to compare times within trials. There was a greater increase in the leukocyte count after high-intensity exercise, compared to the control condition ( p  < 0.01) and low-intensity exercise ( p  < 0.01). This effect was still present 2 hours after passive recovery ( p  < 0.01). When the same participants were submitted to different exercise intensities, the acute and short-term effects of exercise on white blood cells were intensity-dependent immediately after exercise (i.e., lymphocytosis and monocytosis) and 2 hours after passive recovery (i.e., neutrophilia).

Effect of antecedent moderate-intensity exercise on the glycemia-increasing effect of a 30-sec maximal sprint: a sex comparison.

PubMed

Justice, Tara D; Hammer, Greta L; Davey, Raymond J; Paramalingam, Nirubasini; Guelfi, Kym J; Lewis, Lynley; Davis, Elizabeth A; Jones, Timothy W; Fournier, Paul A

2015-05-01

This study investigated whether a prior bout of moderate-intensity exercise attenuates the glycemia-increasing effect of a maximal 30-sec sprint. A secondary aim was to determine whether the effect of antecedent exercise on the glucoregulatory response to sprinting is affected by sex. Participants (men n = 8; women n = 7) were tested on two occasions during which they either rested (CON) or cycled for 60-min at a moderate intensity of ~65% V ˙ O 2 peak (EX) before performing a 30-sec maximal cycling effort 195 min later. In response to the sprint, blood glucose increased to a similar extent between EX and CON trials, peaking at 10 min of recovery, with no difference between sexes (P > 0.05). Blood glucose then declined at a faster rate in EX, and this was associated with a glucose rate of disappearance (R d) that exceeded the glucose rate of appearance (R a) earlier in EX compared with CON, although the overall glucose R a and R d profile was higher in men compared with women (P < 0.05). The response of growth hormone was attenuated during recovery from EX compared with CON (P < 0.05), with a lower absolute response in women compared with men (P < 0.05). The response of epinephrine and norepinephrine was also lower in women compared with men (P < 0.05) but similar between trials. In summary, a prior bout of moderate-intensity exercise does not affect the magnitude of the glycemia-increasing response to a 30-sec sprint; however, the subsequent decline in blood glucose is more rapid. This blood glucose response is similar between men and women, despite less pronounced changes in glucose R a and R d, and a lower response of plasma catecholamines and growth hormone to sprinting in women. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Dose-response relationships between exercise intensity, cravings, and inhibitory control in methamphetamine dependence: An ERPs study.

PubMed

Wang, Dongshi; Zhou, Chenglin; Zhao, Min; Wu, Xueping; Chang, Yu-Kai

2016-04-01

The present study integrated behavioral and neuroelectric approaches for determining the dose-response relationships between exercise intensity and methamphetamine (MA) craving and between exercise intensity and inhibitory control in individuals with MA dependence. Ninety-two individuals with MA dependence were randomly assigned to an exercise group (light, moderate, or vigorous intensity) or to a reading control group. The participants then completed a craving self-report at four time points: before exercise, during exercise, immediately after exercise, and 50 min after exercise. Event-related potentials were also recorded while the participants completed a standard Go/NoGo task and an MA-related Go/NoGo task approximately 20 min after exercise cessation. The reduction in self-reported MA craving scores of the moderate and vigorous intensity groups was greater than that of the light intensity and control groups during acute exercise as well as immediately and 50 min following exercise termination. Additionally, an inverted-U-shaped relationship between exercise intensity and inhibitory control was generally observed for the behavioral and neuroelectric indices, with the moderate intensity group exhibiting shorter Go reaction times, increased NoGo accuracy, and larger NoGo-N2 amplitudes. Acute exercise may provide benefits for MA-associated craving and inhibitory control in MA-dependent individuals, as revealed by behavioral and neuroelectric measures. Moderate-intensity exercise may be associated with more positive effects, providing preliminary evidence for the establishment of an exercise prescription regarding intensity for MA dependence. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

NASA Astrophysics Data System (ADS)

Gurley, Katelyn; Shang, Yu; Yu, Guoqiang

2012-07-01

This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (\\Vdot O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and \\Vdot O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and THC), tissue oxygen saturation (StO2), relative BF (rBF), and relative oxygen consumption rate (r\\Vdot O2). The rBF and r\\Vdot O2 signals were calibrated with absolute baseline BF and \\Vdot O2 obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology.

Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

PubMed Central

Gurley, Katelyn; Shang, Yu

2012-01-01

Abstract. This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (V˙O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and V˙O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and THC), tissue oxygen saturation (StO2), relative BF (rBF), and relative oxygen consumption rate (rV˙O2). The rBF and rV˙O2 signals were calibrated with absolute baseline BF and V˙O2 obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology. PMID:22894482

Endurance exercise intensity determination in the rehabilitation of coronary artery disease patients: a critical re-appraisal of current evidence.

PubMed

Hansen, Dominique; Stevens, An; Eijnde, Bert O; Dendale, Paul

2012-01-01

In the care of coronary artery disease (CAD) patients, the benefits of exercise therapy are generally established. Even though the selected endurance exercise intensity might affect medical safety, therapy adherence and effectiveness in the rehabilitation of CAD patients in how to determine endurance exercise intensity properly remains difficult. The aim of this review is to describe the available methods for endurance exercise intensity determination in the rehabilitation of CAD patients, accompanied with their (dis)advantages, validity and reproducibility. In general, endurance exercise intensity can objectively be determined in CAD patients by calculating a fraction of maximal exercise tolerance and/or determining ventilatory threshold after execution of a cardiopulmonary exercise test with ergospirometry. This can be translated to a corresponding training heart rate (HR) or workload. In the absence of ergospirometry equipment, target exercise HR can be calculated directly by different ways (fraction of maximal HR and/or Karvonen formula), and/or anaerobic threshold can be determined. However, the use of HR for determining exercise intensity during training sessions seems complicated, because many factors/conditions affect the HR. In this regard, proper standardization of the exercise sessions, as well as exercise testing, might be required to improve the accuracy of exercise intensity determination. Alternatively, subjective methods for the determination of endurance exercise intensity in CAD patients, such as the Borg ratings of perceived exertion and the talk test, have been developed. However, these methods lack proper validity and reliability to determine endurance exercise intensity in CAD patients. In conclusion, a practical and systematic approach for the determination of endurance exercise intensity in CAD patients is presented in this article.

Oscillation of tissue oxygen index in non-exercising muscle during exercise.

PubMed

Yano, T; Afroundeh, R; Shirakawa, K; Lian, C-S; Shibata, K; Xiao, Z; Yunoki, T

2015-09-01

The purpose of the present study was to examine how oscillation of tissue oxygen index (TOI) in non-exercising exercise is affected during high-intensity and low-intensity exercises. Three exercises were performed with exercise intensities of 30% and 70% peak oxygen uptake (Vo(2)peak) for 12 min and with exercise intensity of 70% Vo(2)peak for 30 s. TOI in non-exercising muscle (biceps brachii) during the exercises for 12 min was determined by nearinfrared spectroscopy. TOI in the non-exercising muscle during the exercises was analyzed by fast Fourier transform (FFT) to obtain power spectra density (PSD). The frequency at which maximal PSD appeared (Fmax) during the exercise with 70% Vo(2)peak for 12 min (0.00477 ± 0.00172 Hz) was significantly lower than that during the exercise with 30% Vo2peak for 12 min (0.00781 ± 0.00338 Hz). There were significant differences in blood pH and blood lactate between the exercise with 70% Vo(2)peak and the exercise with 30% Vo(2)peak. It is concluded that TOI in nonexercising muscle oscillates during low-intensity exercise as well as during high-intensity exercise and that the difference in Fmax between the two exercises is associated with the difference in increase in blood lactate derived from the exercise.

Hypoxia and training-induced adaptation of hormonal responses to exercise in humans.

PubMed

Engfred, K; Kjaer, M; Secher, N H; Friedman, D B; Hanel, B; Nielsen, O J; Bach, F W; Galbo, H; Levine, B D

1994-01-01

To establish whether or not hypoxia influences the training-induced adaptation of hormonal responses to exercise, 21 healthy, untrained subjects (2) years, mean (SE)] were studied in three groups before and after 5 weeks' training (cycle ergometer, 45 min.day-1, 5 days.week-1). Group 1 trained at sea level at 70% maximal oxygen uptake (VO2max), group 2 in a hypobaric chamber at a simulated altitude of 2500 m at 70% of altitude VO2max, and group 3 at a simulated altitude of 2500 m at the same absolute work rate as group 1. Arterial blood was sampled before, during and at the end of exhaustive cycling at sea level (85% of pretraining VO2max). VO2max increased by 12 (2)% with no significant difference between groups, whereas endurance improved most in group 1 (P < 0.05). Training-induced changes in response to exercise of noradrenaline, adrenaline, growth hormone, beta-endorphin, glucagon, and insulin were similar in the three groups. Concentrations of erythropoietin and 2,3-diphosphoglycerate at rest did not change over the training period. In conclusion, within 5 weeks of training, no further adaptation of hormonal exercise responses takes place if intensity is increased above 70% VO2max. Furthermore, hypoxia per se does not add to the training-induced hormonal responses to exercise.

Exercise intensity-dependent changes in the inflammatory response in sedentary women: role of neuroendocrine parameters in the neutrophil phagocytic process and the pro-/anti-inflammatory cytokine balance.

PubMed

Giraldo, E; Garcia, J J; Hinchado, M D; Ortega, E

2009-01-01

It is still not really known what is the optimal level of exercise that improves, but does not impair or overstimulate the innate immune function. This is especially the case in women, who have higher basal levels of 'inflammatory markers' than men. The aim of this work was to evaluate differences in the magnitude of the stimulation of the innate/inflammatory response following a single bout of moderate or intense exercise in sedentary women, all of them in the follicular phase of their menstrual cycle. Changes in stress and sexual hormones were also evaluated. Changes induced by exercise (45 min at 55% VO(2) max vs. 1 h at 70% VO(2) max on a cycle ergometer) in the phagocytic process (chemotaxis, phagocytosis, and microbicide capacity against Candida albicans) and in serum concentrations of IL-1beta, IL-2, IFN-gamma, IL-12, IL-6, and IL-4 (ELISA) were evaluated. Parallel determinations were also made of serum or plasma concentrations of catecholamines (HPLC) and cortisol, oestradiol, and progesterone (electrochemiluminescence immunoassay). Both exercise intensities increased chemotaxis, phagocytosis, and microbicide capacity of the neutrophils. However, the increase in chemotaxis was greater after moderate exercise. All the cytokines assayed were affected by exercise intensity. IFN-gamma increased significantly only immediately after the intense exercise; IL-1beta increased following both exercise intensities, although at 24 h it only remained elevated after the intense exercise; IL-12 only increased 24 h after the intense exercise, and IL-2 only showed a significant decrease following the moderate exercise. IL-6 increased immediately after both exercise intensities, but more so after moderate exercise. While IL-4 (an anti-inflammatory cytokine) increased following the moderate exercise, it decreased after the intense exercise. Both moderate and intense exercise increased norepinephrine and decreased cortisol, both of which returned to basal levels after 24 h. Only the intense exercise affected the epinephrine, oestradiol, and progesterone concentrations, with increases in epinephrine and oestradiol immediately after exercise, and a decrease in progesterone after 24 h. Both moderate and intense exercise stimulate the phagocytic process of neutrophils in sedentary women, but the profile of pro-/anti-inflammatory cytokine release seems to be better following the moderate exercise. The possible participation of stress (catecholamines and cortisol) and sex (oestradiol and progesterone) hormones in these intensity-dependent immune changes is discussed. Copyright 2009 S. Karger AG, Basel.

PGC-1α and exercise intensity dependent adaptations in mouse skeletal muscle

PubMed Central

Dethlefsen, Maja Munk; Bangsbo, Jens; Pilegaard, Henriette

2017-01-01

The aim of the present study was to examine the role of PGC-1α in intensity dependent exercise and exercise training-induced metabolic adaptations in mouse skeletal muscle. Whole body PGC-1α knockout (KO) and littermate wildtype (WT) mice performed a single treadmill running bout at either low intensity (LI) for 40 min or moderate intensity (MI) for 20 min. Blood and quadriceps muscles were removed either immediately after exercise or at 3h or 6h into recovery from exercise and from resting controls. In addition PGC-1α KO and littermate WT mice were exercise trained at either low intensity (LIT) for 40 min or at moderate intensity (MIT) for 20 min 2 times pr. day for 5 weeks. In the first and the last week of the intervention period, mice performed a graded running endurance test. Quadriceps muscles were removed before and after the training period for analyses. The acute exercise bout elicited intensity dependent increases in LC3I and LC3II protein and intensity independent decrease in p62 protein in skeletal muscle late in recovery and increased LC3II with exercise training independent of exercise intensity and volume in WT mice. Furthermore, acute exercise and exercise training did not increase LC3I and LC3II protein in PGC-1α KO. In addition, exercise-induced mRNA responses of PGC-1α isoforms were intensity dependent. In conclusion, these findings indicate that exercise intensity affected autophagy markers differently in skeletal muscle and suggest that PGC-1α regulates both acute and exercise training-induced autophagy in skeletal muscle potentially in a PGC-1α isoform specific manner. PMID:29049322

The effect of a 3-month supervised exercise programme on gait parameters of patients with peripheral arterial disease and intermittent claudication.

PubMed

King, Stephanie; Vanicek, Natalie; Mockford, Katherine A; Coughlin, Patrick A

2012-10-01

The management of peripheral arterial disease with intermittent claudication includes angioplasty, pharmaceutical therapy, risk factor modification and exercise therapy. Supervised exercise programmes are used sporadically but may improve the distance that an individual with claudication can walk. The purpose of this study was to evaluate the effectiveness of a 3-month supervised exercise programme on improving gait parameters in patients with intermittent claudication. 12 participants were recruited (mean (SD) - age: 67.3 (6.8) years, height: 1.67 (0.09) m, mass: 79.4 (14.0) kg, ankle brachial pressure index: 0.73 (0.17)) from the local vascular unit and enrolled in a supervised exercise programme. Kinematic and kinetic data were collected at the following time points: pain-free walking, initial claudication pain, absolute claudication pain and after a patient-defined rest period. Data were collected before and after the 3-month supervised exercise programme. No significant differences were found in any of the gait parameters post-intervention including pain-free walking speed (P=0.274), peak hip extension (P=0.125), peak ankle plantarflexion (P=0.254), or first vertical ground reaction force peak (P=0.654). No significant gait differences were found across different levels of pain pre- or post-intervention. The lack of improvement post-intervention observed suggests that the current exercise protocol was not tailored to elicit significant improvements in patients with intermittent claudication, specifically. The results indicate that exercise programmes may show improved results post-intervention if they are longer in duration and varied in intensity. Further research into more detailed muscle and biomechanical adaptations is needed to inform exercise programmes specific to this population. Copyright © 2012 Elsevier Ltd. All rights reserved.

Physical activity and pregnancy: cardiovascular adaptations, recommendations and pregnancy outcomes.

PubMed

Melzer, Katarina; Schutz, Yves; Boulvain, Michel; Kayser, Bengt

2010-06-01

Regular physical activity is associated with improved physiological, metabolic and psychological parameters, and with reduced risk of morbidity and mortality. Current recommendations aimed at improving the health and well-being of nonpregnant subjects advise that an accumulation of > or =30 minutes of moderate physical activity should occur on most, if not all, days of the week. Regardless of the specific physiological changes induced by pregnancy, which are primarily developed to meet the increased metabolic demands of mother and fetus, pregnant women benefit from regular physical activity the same way as nonpregnant subjects. Changes in submaximal oxygen uptake (VO(2)) during pregnancy depend on the type of exercise performed. During maternal rest or submaximal weight-bearing exercise (e.g. walking, stepping, treadmill exercise), absolute maternal VO(2) is significantly increased compared with the nonpregnant state. The magnitude of change is approximately proportional to maternal weight gain. When pregnant women perform submaximal weight-supported exercise on land (e.g. level cycling), the findings are contradictory. Some studies reported significantly increased absolute VO(2), while many others reported unchanged or only slightly increased absolute VO(2) compared with the nonpregnant state. The latter findings may be explained by the fact that the metabolic demand of cycle exercise is largely independent of the maternal body mass, resulting in no absolute VO(2) alteration. Few studies that directly measured changes in maternal maximal VO(2) (VO(2max)) showed no difference in the absolute VO(2max) between pregnant and nonpregnant subjects in cycling, swimming or weight-bearing exercise. Efficiency of work during exercise appears to be unchanged during pregnancy in non-weight-bearing exercise. During weight-bearing exercise, the work efficiency was shown to be improved in athletic women who continue exercising and those who stop exercising during pregnancy. When adjusted for weight gain, the increased efficiency is maintained throughout the pregnancy, with the improvement being greater in exercising women. Regular physical activity has been proven to result in marked benefits for mother and fetus. Maternal benefits include improved cardiovascular function, limited pregnancy weight gain, decreased musculoskeletal discomfort, reduced incidence of muscle cramps and lower limb oedema, mood stability, attenuation of gestational diabetes mellitus and gestational hypertension. Fetal benefits include decreased fat mass, improved stress tolerance, and advanced neurobehavioural maturation. In addition, few studies that have directly examined the effects of physical activity on labour and delivery indicate that, for women with normal pregnancies, physical activity is accompanied with shorter labour and decreased incidence of operative delivery. However, a substantial proportion of women stop exercising after they discover they are pregnant, and only few begin participating in exercise activities during pregnancy. The adoption or continuation of a sedentary lifestyle during pregnancy may contribute to the development of certain disorders such as hypertension, maternal and childhood obesity, gestational diabetes, dyspnoea, and pre-eclampsia. In view of the global epidemic of sedentary behaviour and obesity-related pathology, prenatal physical activity was shown to be useful for the prevention and treatment of these conditions. Further studies with larger sample sizes are required to confirm the association between physical activity and outcomes of labour and delivery.

High intensity exercise or conventional exercise for patients with rheumatoid arthritis? Outcome expectations of patients, rheumatologists, and physiotherapists

PubMed Central

Munneke, M; de Jong, Z; Zwinderman, A; Ronday, H; van den Ende, C H M; Vliet, V; Hazes, J

2004-01-01

Objective: To examine the outcome expectations of RA patients, rheumatologists, and physiotherapists regarding high intensity exercise programmes compared with conventional exercise programmes. Methods: An exercise outcome expectations questionnaire was administered to 807 RA patients, 153 rheumatologists, and 624 physiotherapists. The questionnaire consisted of four statements regarding positive and negative outcomes of high intensity exercise programmes and four similar statements for conventional exercise programmes. A total expectation score for both conventional and high intensity exercise was calculated, ranging from –2 (very negative expectation) to 2 (very positive expectation). Results: The questionnaire was returned by 662 RA patients (82%), 132 rheumatologists (86%), and 467 physiotherapists (75%). The mean (95% confidence interval) scores for high intensity exercise programmes were 0.30 (0.25 to 0.34), 0.68 (0.62 to 0.74), and –0.06 (–0.15 to 0.02), and for conventional exercise programmes were 0.99 (0.96 to 1.02), 1.13 (1.09 to 1.17), and 1.27 (1.21 to 1.34) for RA patients, rheumatologists, and physiotherapists, respectively. In all three respondent groups, the outcome expectations of high intensity exercise were significantly less positive than those of conventional exercise programme. Conclusions: Despite the existing evidence regarding the effectiveness and safety of high intensity exercise programmes, RA patients, rheumatologists, and physiotherapists have more positive expectations of conventional exercise programmes than of high intensity exercise programmes. Physiotherapists were the least positive about outcomes of high intensity exercise programmes while rheumatologists were the most positive. To help the implementation of new insights in the effectiveness of physical therapy modalities in rheumatology, the need for continuous education of patients, rheumatologists and physiotherapists is emphasised. PMID:15194575

Reliability of laser Doppler, near-infrared spectroscopy and Doppler ultrasound for peripheral blood flow measurements during and after exercise in the heat.

PubMed

Choo, Hui C; Nosaka, Kazunori; Peiffer, Jeremiah J; Ihsan, Mohammed; Yeo, Chow C; Abbiss, Chris R

2017-09-01

This study examined the test-retest reliability of near-infrared spectroscopy (NIRS), laser Doppler flowmetry (LDF) and Doppler ultrasound to assess exercise-induced haemodynamics. Nine men completed two identical trials consisting of 25-min submaximal cycling at first ventilatory threshold followed by repeated 30-s bouts of high-intensity (90% of peak power) cycling in 32.8 ± 0.4°C and 32 ± 5% relative humidity (RH). NIRS (tissue oxygenation index [TOI] and total haemoglobin [tHb]) and LDF (perfusion units [PU]) signals were monitored continuously during exercise, and leg blood flow was assessed by Doppler ultrasound at baseline and after exercise. Cutaneous vascular conductance (CVC; PU/mean arterial pressure (MAP)) was expressed as the percentage change from baseline (%CVC BL ). Coefficients of variation (CVs) as indicators of absolute reliability were 18.7-28.4%, 20.2-33.1%, 42.5-59.8%, 7.8-12.4% and 22.2-30.3% for PU, CVC, %CVC BL , TOI and tHb, respectively. CVs for these variables improved as exercise continued beyond 10 min. CVs for baseline and post-exercise leg blood flow were 17.8% and 10.5%, respectively. CVs for PU, tHb (r 2  = 0.062) and TOI (r 2  = 0.002) were not correlated (P > 0.05). Most variables demonstrated CVs lower than the expected changes (35%) induced by training or heat stress; however, minimum of 10 min exercise is recommended for more reliable measurements.

Prediction of absolute infrared intensities for the fundamental vibrations of H2O2

NASA Technical Reports Server (NTRS)

Rogers, J. D.; Hillman, J. J.

1981-01-01

Absolute infrared intensities are predicted for the vibrational bands of gas-phase H2O2 by the use of a hydrogen atomic polar tensor transferred from the hydroxyl hydrogen atom of CH3OH. These predicted intensities are compared with intensities predicted by the use of a hydrogen atomic polar tensor transferred from H2O. The predicted relative intensities agree well with published spectra of gas-phase H2O2, and the predicted absolute intensities are expected to be accurate to within at least a factor of two. Among the vibrational degrees of freedom, the antisymmetric O-H bending mode nu(6) is found to be the strongest with a calculated intensity of 60.5 km/mole. The torsional band, a consequence of hindered rotation, is found to be the most intense fundamental with a predicted intensity of 120 km/mole. These results are compared with the recent absolute intensity determinations for the nu(6) band.

Influence of Exercise Intensity for Improving Depressed Mood in Depression: A Dose-Response Study.

PubMed

Meyer, Jacob D; Koltyn, Kelli F; Stegner, Aaron J; Kim, Jee-Seon; Cook, Dane B

2016-07-01

Exercise effectively improves mood in major depressive disorder (MDD), but the optimal exercise stimulus to improve depressed mood is unknown. To determine the dose-response relationship of acute exercise intensity with depressed mood responses to exercise in MDD. We hypothesized that the acute response to exercise would differ between light, moderate, and hard intensity exercise with higher intensities yielding more beneficial responses. Once weekly, 24 women (age: 38.6±14.0) diagnosed with MDD underwent a 30-minute session at one of three steady-state exercise intensities (light, moderate, hard; rating of perceived exertion 11, 13 or 15) or quiet rest on a stationary bicycle. Depressed mood was evaluated with the Profile of Mood States before, 10 and 30 minutes post-exercise. Exercise reduced depressed mood 10 and 30 minutes following exercise, but this effect was not influenced by exercise intensity. Participants not currently taking antidepressants (n=10) had higher baseline depression scores, but did not demonstrate a different antidepressant response to exercise compared to those taking antidepressants. To acutely improve depressed mood, exercise of any intensity significantly improved feelings of depression with no differential effect following light, moderate, or hard exercise. Pharmacological antidepressant usage did not limit the mood-enhancing effect of acute exercise. Acute exercise should be used as a symptom management tool to improve mood in depression, with even light exercise an effective recommendation. These results need to be replicated and extended to other components of exercise prescription (e.g., duration, frequency, mode) to optimize exercise guidelines for improving depression. Copyright © 2016. Published by Elsevier Ltd.

High-intensity exercise training induces morphological and biochemical changes in skeletal muscles.

PubMed

Toti, L; Bartalucci, A; Ferrucci, M; Fulceri, F; Lazzeri, G; Lenzi, P; Soldani, P; Gobbi, P; La Torre, A; Gesi, M

2013-12-01

IN THE PRESENT STUDY WE INVESTIGATED THE EFFECT OF TWO DIFFERENT EXERCISE PROTOCOLS ON FIBRE COMPOSITION AND METABOLISM OF TWO SPECIFIC MUSCLES OF MICE: the quadriceps and the gastrocnemius. Mice were run daily on a motorized treadmill, at a velocity corresponding to 60% or 90% of the maximal running velocity. Blood lactate and body weight were measured during exercise training. We found that at the end of training the body weight significantly increased in high-intensity exercise mice compared to the control group (P=0.0268), whereas it decreased in low-intensity exercise mice compared to controls (P=0.30). In contrast, the food intake was greater in both trained mice compared to controls (P < 0.0001 and P < 0.0001 for low-intensity and high-intensity exercise mice, respectively). These effects were accompanied by a progressive reduction in blood lactate levels at the end of training in both the exercised mice compared with controls (P=0.03 and P < 0.0001 for low-intensity and high-intensity exercise mice, respectively); in particular, blood lactate levels after high-intensity exercise were significantly lower than those measured in low-intensity exercise mice (P=0.0044). Immunoblotting analysis demonstrated that high-intensity exercise training produced a significant increase in the expression of mitochondrial enzymes contained within gastrocnemius and quadriceps muscles. These changes were associated with an increase in the amount of slow fibres in both these muscles of high-intensity exercise mice, as revealed by the counts of slow fibres stained with specific antibodies (P < 0.0001 for the gastrocnemius; P=0.0002 for the quadriceps). Our results demonstrate that high-intensity exercise, in addition to metabolic changes consisting of a decrease in blood lactate and body weight, induces an increase in the mitochondrial enzymes and slow fibres in different skeletal muscles of mice, which indicates an exercise-induced increase in the aerobic metabolism.

An Evidence-Based Approach To Exercise Prescriptions on ISS

NASA Technical Reports Server (NTRS)

Ploutz-Snyder, Lori

2009-01-01

This presentation describes current exercise countermeasures and exercise equipment for astronauts onboard the ISS. Additionally, a strategy for evaluating evidence supporting spaceflight exercise is described and a new exercise prescription is proposed. The current exercise regimen is not fully effective as the ISS exercise hardware does not allow for sufficient exercise intensity, the exercise prescription is adequate and crew members are noncompliant with the prescription. New ISS hardware is proposed, Advanced Resistance Exercise Device (ARED), which allows additional exercises, is instrumented for data acquisition and offers improved loading. The new T2 hardware offers a better harness and subject loading system, is instrumented to allow ground reaction force data, and offers improved speed. A strategy for developing a spaceflight exercise prescription is described and involves identifying exercise training programs that have been shown to maximize adaptive benefits of people exercising in both 0 and 1 g environments. Exercise intensity emerged as an important factor in maintaining physiologic adaptations in the spaceflight environment and interval training is suggested. New ISS exercise hardware should allow for exercise at intensities high enough to elicit adaptive responses. Additionally, new exercise prescriptions should incorporate higher intensity exercises and seek to optimize intensity, duration and frequency for greater efficiency.

Older adults show higher increases in lower-limb muscle activity during whole-body vibration exercise.

PubMed

Lienhard, Karin; Vienneau, Jordyn; Nigg, Sandro; Friesenbichler, Bernd; Nigg, Benno M

2017-02-08

The purpose of this study was to compare lower limb muscle activity during whole-body vibration (WBV) exercise between a young and an older study population. Thirty young (25.9±4.3yrs) and thirty older (64.2±5.3yrs) individuals stood on a side-alternating WBV platform while surface electromyography (sEMG) was measured for the tibialis anterior (TA), gastrocnemius medialis (GM), soleus (SOL), vastus lateralis (VL), vastus medialis (VM), and biceps femoris (BF). The WBV protocol included nine vibration settings consisting of three frequencies (6, 11, 16Hz) x three amplitudes (0.9, 2.5, 4.0mm), and three control trials without vibration (narrow, medium, wide stance). The vertical platform acceleration (peak values of maximal displacement from equilibrium) was quantified during each vibration exercise using an accelerometer. The outcomes of this study showed that WBV significantly increased muscle activity in both groups for most vibration conditions in the TA (averaged absolute increase: young: +3.9%, older: +18.4%), GM (young: +4.1%, older: +9.5%), VL (young: +6.3%, older: +12.6%) and VM (young: +5.4%, older: +8.0%), and for the high frequency-amplitude combinations in the SOL (young: +7.5%, older: +12.6%) and BF (young: +1.9%, older: +7.5%). The increases in sEMG activity were significantly higher in the older than the young adults for all muscles, i.e., TA (absolute difference: 13.8%, P<0.001), GM (4.6%, P=0.034), VL (7.6%, P=0.001), VM (6.7%, P=0.042), BF (6.4%, P<0.001), except for the SOL (0.3%, P=0.248). Finally, the vertical platform acceleration was a significant predictor of the averaged lower limb muscle activity in the young (r=0.917, P<0.001) and older adults (r=0.931, P<0.001). In conclusion, the older population showed greater increases in lower limb muscle activity during WBV exercise than their young counterparts, meaning that they might benefit more from WBV exercises. Additionally, training intensity can be increased by increasing the vertical acceleration load. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pourquoi les exercices de grammaire? (Why Grammar Exercises?)

ERIC Educational Resources Information Center

Bastuji, Jacqueline

1977-01-01

Recent theories and experiementation running the gamut from the absolute necessity of grammar to its uselessness in teaching a language form the basis of this article. Topics covered are: a typology of the grammar exercise; explicit grammar and linguistic competence; grammar exercises responding to real needs. (Text is in French.) (AMH)

Caffeine affects CD8+ lymphocyte apoptosis and migration differently in naïve and familiar individuals following moderate intensity exercise.

PubMed

Navalta, James W; Fedor, Elizabeth A; Schafer, Mark A; Lyons, T Scott; Tibana, Ramires A; Pereira, Guilherme B; Prestes, Jonato

2016-06-01

The purpose of this investigation was to determine the lymphocyte subset response to 30 min of moderate treadmill exercise during caffeine supplemented (6.0 mg.kg(-1)) and placebo conditions in caffeine-naïve and -familiar individuals. Seventeen individuals participated (caffeine-familiar = 8, caffeine-naïve = 9) completing two exercise bouts (caffeine supplemented and placebo control) 48 h apart in a counterbalanced and double-blinded fashion. Individuals were classified as follows: caffeine-naive <50 mg.d(-1) and caffeine-familiar >200 mg.d(-1) Whole blood samples were obtained at rest, 30 min after caffeine or placebo ingestion, immediately following exercise, and 1 h post exercise. Blood was used to analyze apoptosis (annexin V) and cellular migration (CX3CR1) responses in lymphocyte subsets (CD4+, CD8+, CD19+). Absolute changes from rest values were calculated and differences between conditions were determined through Chi-squared analysis with significance accepted at P <0.05. With regard to CD4+ and CD19+ lymphocytes, the interaction of caffeine and exercise did not affect naïve individuals to a greater extent immediately post exercise when compared to familiar, as similar apoptotic and migratory responses were observed (P >0.05). However, CD8+ lymphocyte cell death and migration responses were observed to be significantly greater at each sampling point in caffeine-familiar individuals (P <0.05). It is possible that chronic caffeine supplementation may prime CD8+ cell receptors for responsiveness to apoptosis and migration and the consequence of this form of immunosuppression in the post-exercise period should be determined. © The Author(s) 2015.

High-Intensity Locomotor Exercise Increases Brain-Derived Neurotrophic Factor in Individuals with Incomplete Spinal Cord Injury.

PubMed

Leech, Kristan A; Hornby, T George

2017-03-15

High-intensity locomotor exercise is suggested to contribute to improved recovery of locomotor function after neurological injury. This may be secondary to exercise-intensity-dependent increases in neurotrophin expression demonstrated previously in control subjects. However, rigorous examination of intensity-dependent changes in neurotrophin levels is lacking in individuals with motor incomplete spinal cord injury (SCI). Therefore, the primary aim of this study was to evaluate the effect of locomotor exercise intensity on peripheral levels of brain-derived neurotrophic factor (BDNF) in individuals with incomplete SCI. We also explored the impact of the Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene on intensity-dependent changes. Serum concentrations of BDNF and insulin-like growth factor-1 (IGF-1), as well as measures of cardiorespiratory dynamics, were evaluated across different levels of exercise intensity achieved during a graded-intensity, locomotor exercise paradigm in 11 individuals with incomplete SCI. Our results demonstrate a significant increase in serum BDNF at high, as compared to moderate, exercise intensities (p = 0.01) and 15 and 30 min post-exercise (p < 0.01 for both), with comparison to changes at low intensity approaching significance (p = 0.05). Serum IGF-1 demonstrated no intensity-dependent changes. Significant correlations were observed between changes in BDNF and specific indicators of exercise intensity (e.g., rating of perceived exertion; R = 0.43; p = 0.02). Additionally, the data suggest that Val66Met SNP carriers may not exhibit intensity-dependent changes in serum BDNF concentration. Given the known role of BDNF in experience-dependent neuroplasticity, these preliminary results suggest that exercise intensity modulates serum BDNF concentrations and may be an important parameter of physical rehabilitation interventions after neurological injury.

Can previously sedentary females use the feeling scale to regulate exercise intensity in a gym environment? an observational study.

PubMed

Hamlyn-Williams, Charlotte C; Tempest, Gavin; Coombs, Sarah; Parfitt, Gaynor

2015-01-01

Recent research suggests that the Feeling Scale (FS) can be used as a method of exercise intensity regulation to maintain a positive affective response during exercise. However, research to date has been carried out in laboratories and is not representative of natural exercise environments. The purpose of this study was to evaluate whether sedentary women can self-regulate their exercise intensity using the FS to experience positive affective responses in a gym environment using their own choice of exercise mode; cycling or treadmill. Fourteen females (24.9 years ± 5.2; height 166.7 ± 5.7 cm; mass 66.3 ± 13.4 kg; BMI 24.1 ± 5.5)) completed a submaximal exercise test and each individual's ventilatory threshold ([Formula: see text]) was identified. Following this, three 20 min gym-based exercise trials, either on a bike or treadmill were performed at an intensity that was self-selected and perceived to correspond to the FS value of +3 (good). Oxygen uptake, heart rate (HR) and ratings of perceived exertion (RPE) were measured during exercise at the participants chosen intensity. Results indicated that on average participants worked close to their [Formula: see text] and increased their exercise intensity during the 20-min session. Participants worked physiologically harder during cycling exercise. Consistency of oxygen uptake, HR and RPE across the exercise trials was high. The data indicate that previously sedentary women can use the FS in an ecological setting to regulate their exercise intensity and that regulating intensity to feel 'good' should lead to individuals exercising at an intensity that would result in cardiovascular gains if maintained.

Autonomic dysfunction predicts poor physical improvement after cardiac rehabilitation in patients with heart failure.

PubMed

Compostella, Leonida; Nicola, Russo; Tiziana, Setzu; Caterina, Compostella; Fabio, Bellotto

2014-11-01

Cardiac autonomic dysfunction, clinically expressed by reduced heart rate variability (HRV), is present in patients with congestive heart failure (CHF) and is related to the degree of left ventricular dysfunction. In athletes, HRV is an indicator of ability to improve performance. No similar data are available for CHF. The aim of this study was to assess whether HRV could predict the capability of CHF patients to improve physical fitness after a short period of exercise-based cardiac rehabilitation (CR). This was an observational, non-randomized study, conducted on 57 patients with advanced CHF, admitted to a residential cardiac rehabilitation unit 32 ± 22 days after an episode of acute heart failure. Inclusion criteria were sinus rhythm, stable clinical conditions, no diabetes and ejection fraction ≤ 35%. HRV (time-domain) and mean and minimum heart rate (HR) were evaluated using 24-h Holter at admission. Patients' physical fitness was evaluated at admission by 6-minute walking test (6MWT) and reassessed after two weeks of intensive exercise-based CR. Exercise capacity was evaluated by a symptom-limited cardiopulmonary exercise test (CPET). Patients with very depressed HRV (SDNN 55.8 ± 10.0 ms) had no improvement in their walking capacity after short CR, walked shorter absolute distances at final 6MWT (348 ± 118 vs. 470 ± 109 m; P = 0.027) and developed a peak-VO2 at CPET significantly lower than patients with greater HRV parameters (11.4 ± 3.7 vs. an average > 16 ± 4 mL/kg/min). Minimum HR, but not mean HR, showed a negative correlation (ρ = -0.319) with CPET performance. In patients with advanced CHF, depressed HRV and higher minimum HR were predictors of poor working capacity after a short period of exercise-based CR. An individualized and intensive rehabilitative intervention should be considered for these patients.

Glucose response to exercise in the post-prandial period is independent of exercise intensity.

PubMed

Shambrook, P; Kingsley, M I; Wundersitz, D W; Xanthos, P D; Wyckelsma, V L; Gordon, B A

2018-03-01

This study investigated the acute glucose response to low-intensity, moderate-intensity, and high-intensity interval exercise compared to no-exercise in healthy insufficiently active males using a four-arm, randomized, crossover design. Ten males (age: 37.3 ± 7.3 years, BMI: 29.3 ± 6.5 kg·m -2 ) completed four 30-minute interventions at weekly intervals comprising low-intensity exercise (LIE) at ~35% V˙O 2 R, moderate-intensity exercise (MIE) at ~50% V˙O 2 R, high-intensity interval exercise (HIIE) at ~80% V˙O 2 R, and a no-exercise control. Participants performed cycle ergometer exercise 30 minutes after finishing breakfast. Glucose response was assessed using a continuous glucose monitor under free-living conditions with dietary intake replicated. A significant effect for intensity on energy expenditure was identified (P < .001) with similar energy cost in MIE (mean ± SD: 869 ± 148 kJ) and HIIE (806 ± 145 kJ), which were both greater than LIE (633 ± 129 kJ). The pattern of glucose response between the interventions over time was different (P = .02). Glucose was lower 25 minutes into each of the HIIE, MIE and LIE trials respectively (mean difference ± SD: -0.7 ± 1.1; -0.9 ± 1.1; -0.6 ± 0.9 mmol·L -1 ; P < .05) than in the no-exercise trial. Glucose response was not different between exercise intensities (P > .05). Twenty-four-hour AUC was not affected by exercise intensity (P = .75). There was a significant effect for exercise enjoyment (P = .02), with LIE (69 ± 4) preferred less than HIIE (mean ± SD: 84 ± 14; P = .02), MIE (73 ± 5; P = .03), and no-exercise (75 ± 4; P = .03). Exercise at any intensity 30 minutes after a meal affects glycemic regulation equally in insufficiently active males. Moderate to vigorous exercise intensities were preferred, and therefore, the exercise guidelines appear appropriate for the prevention of cardiometabolic disease. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Neoagarotetraose protects mice against intense exercise induced stress by modulating gut microbial composition and function

USDA-ARS?s Scientific Manuscript database

Exhaustive exercise stress has emerged as an important health issue, and gastrointestinal problems are a common concern during intense exercise. In this study, we investigated potential anti-fatigue effects of neoagarotetraose (NAT) in mice under intense exercise stress. Exhaustive exercise stress s...

High-Intensity Locomotor Exercise Increases Brain-Derived Neurotrophic Factor in Individuals with Incomplete Spinal Cord Injury

PubMed Central

Leech, Kristan A.

2017-01-01

Abstract High-intensity locomotor exercise is suggested to contribute to improved recovery of locomotor function after neurological injury. This may be secondary to exercise-intensity–dependent increases in neurotrophin expression demonstrated previously in control subjects. However, rigorous examination of intensity-dependent changes in neurotrophin levels is lacking in individuals with motor incomplete spinal cord injury (SCI). Therefore, the primary aim of this study was to evaluate the effect of locomotor exercise intensity on peripheral levels of brain-derived neurotrophic factor (BDNF) in individuals with incomplete SCI. We also explored the impact of the Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene on intensity-dependent changes. Serum concentrations of BDNF and insulin-like growth factor-1 (IGF-1), as well as measures of cardiorespiratory dynamics, were evaluated across different levels of exercise intensity achieved during a graded-intensity, locomotor exercise paradigm in 11 individuals with incomplete SCI. Our results demonstrate a significant increase in serum BDNF at high, as compared to moderate, exercise intensities (p = 0.01) and 15 and 30 min post-exercise (p < 0.01 for both), with comparison to changes at low intensity approaching significance (p = 0.05). Serum IGF-1 demonstrated no intensity-dependent changes. Significant correlations were observed between changes in BDNF and specific indicators of exercise intensity (e.g., rating of perceived exertion; R = 0.43; p = 0.02). Additionally, the data suggest that Val66Met SNP carriers may not exhibit intensity-dependent changes in serum BDNF concentration. Given the known role of BDNF in experience-dependent neuroplasticity, these preliminary results suggest that exercise intensity modulates serum BDNF concentrations and may be an important parameter of physical rehabilitation interventions after neurological injury. PMID:27526567

Can Self-Reported Preference for Exercise Intensity Predict Physiologically Defined Self-Selected Exercise Intensity?

ERIC Educational Resources Information Center

Ekkekakis, Panteleimon; Lind, Erik; Joens-Matre, Roxane R.

2006-01-01

Exercise prescription guidelines emphasize the importance of individual preferences for different intensities, but such preferences have not been studied systematically. This study examined the hypothesis that the preference scale of the Preference for and Tolerance of the Intensity of Exercise Questionnaire would predict self-selected exercise…

Effect of the low- versus high-intensity exercise training on endoplasmic reticulum stress and GLP-1 in adolescents with type 2 diabetes mellitus.

PubMed

Lee, Sung Soo; Yoo, Jae Ho; So, Yong Seok

2015-10-01

[Purpose] The primary objective of this study was to investigate the effect of low-intensity exercise training compare with high-intensity exercise training on endoplasmic reticulum stress and glucagon-like peptide-1 in adolescents with type 2 diabetes mellitus. [Subjects and Methods] The low-intensity exercise training group performed aerobic exercise training at an intensity of ≤ 45% of the heart rate reserve. The high-intensity interval exercise training group performed interval exercise training at an intensity of ≥ 80% of the heart rate reserve. The exercise-related energy consumption was determined for both groups on a per-week basis (1,200 kcal/week). [Results] Both groups showed improvement in the glucose-regulated protein 78 and dipeptidyl peptidase-4, but the size of the between-group effect was not statistically significant. The high-intensity interval exercise training group showed a significant reduction in percentage body fat. The C-peptide level increased after the 12-weeks programs and was significantly different, between the groups. Fasting glucose, insulin resistance in the fasting state according to homeostasis model assessment, and leptin decreased after the 12-weeks exercise program and were significantly different between the groups, and glucagon-like peptide-1 increased after the 12-week exercise programs and was significantly different between the groups. [Conclusion] In conclusion high-intensity interval exercise training, as defined in this study, may lead to improvements in body composition, glycemic control, endoplasmic reticulum stress, and the glucagon-like peptide-1 in adolescents with type 2 diabetes mellitus.

Effect of the low- versus high-intensity exercise training on endoplasmic reticulum stress and GLP-1 in adolescents with type 2 diabetes mellitus

PubMed Central

Lee, Sung Soo; Yoo, Jae Ho; So, Yong Seok

2015-01-01

[Purpose] The primary objective of this study was to investigate the effect of low-intensity exercise training compare with high-intensity exercise training on endoplasmic reticulum stress and glucagon-like peptide-1 in adolescents with type 2 diabetes mellitus. [Subjects and Methods] The low-intensity exercise training group performed aerobic exercise training at an intensity of ≤ 45% of the heart rate reserve. The high-intensity interval exercise training group performed interval exercise training at an intensity of ≥ 80% of the heart rate reserve. The exercise-related energy consumption was determined for both groups on a per-week basis (1,200 kcal/week). [Results] Both groups showed improvement in the glucose-regulated protein 78 and dipeptidyl peptidase-4, but the size of the between-group effect was not statistically significant. The high-intensity interval exercise training group showed a significant reduction in percentage body fat. The C-peptide level increased after the 12-weeks programs and was significantly different, between the groups. Fasting glucose, insulin resistance in the fasting state according to homeostasis model assessment, and leptin decreased after the 12-weeks exercise program and were significantly different between the groups, and glucagon-like peptide-1 increased after the 12-week exercise programs and was significantly different between the groups. [Conclusion] In conclusion high-intensity interval exercise training, as defined in this study, may lead to improvements in body composition, glycemic control, endoplasmic reticulum stress, and the glucagon-like peptide-1 in adolescents with type 2 diabetes mellitus. PMID:26644644

Energy cost of isolated resistance exercises across low- to high-intensities

PubMed Central

Garrido, Nuno Domingos; Vianna, Jeferson; Sousa, Ana Catarina; Alves, José Vilaça; Marques, Mário Cardoso

2017-01-01

This study aimed to estimate the energy cost across various intensities at eight popular resistance exercises: half squat, 45° inclined leg press, leg extension, horizontal bench press, 45° inclined bench press, lat pull down, triceps extension and biceps curl. 58 males (27.5 ± 4.9 years, 1.78 ± 0.06 m height, 78.67 ± 10.7 kg body mass and 11.4 ± 4.1% estimated body fat) were randomly divided into four groups of 14 subjects each. For each group, two exercises were randomly assigned and on different days, they performed four bouts of 5-min constant-intensity for each of the two assigned exercises: 12%, 16%, 20% and 24% 1-RM. Later, the subjects performed exhaustive bouts at 80% 1-RM in the same two exercises. The mean values of VO2 at the last 30s of exercise at 12, 16, 20 and 24% 1-RM bouts were plotted against relative intensity (% 1-RM) in a simple linear regression mode. The regressions were then used to predict O2 demand for the higher intensity (80% 1-RM). Energy cost rose linearly with exercise intensity in every exercise with the lowest mean values were found in biceps curl and the highest in half squat exercise (p<0.001). Half squat exercise presented significant (p<0.001) higher values of energy cost in all intensities, when compared with the remaining exercises. This study revealed that low-intensity resistance exercise provides energy cost comprised between 3 and 10 kcal∙min-1. Energy cost rose past 20 kcal∙min-1 at 80% 1-RM in leg exercise. In addition, at 80% 1-RM, it was found that upper body exercises are less anaerobic than lower-body exercises. PMID:28742112

Does Physical Loading Affect The Speed and Accuracy of Tactical Decision-Making in Elite Junior Soccer Players?

PubMed

Frýbort, Pavel; Kokštejn, Jakub; Musálek, Martin; Süss, Vladimír

2016-06-01

A soccer player's capability to control and manage his behaviour in a game situation is a prerequisite, reflecting not only swift and accurate tactical decision-making, but also prompt implementation of a motor task during intermittent exercise conditions. The purpose of this study was to analyse the relationship between varying exercise intensity and the visual-motor response time and the accuracy of motor response in an offensive game situation in soccer. The participants (n = 42) were male, semi-professional, soccer players (M age 18.0 ± 0.9 years) and trained five times a week. Each player performed four different modes of exercise intensity on the treadmill (motor inactivity, aerobic, intermittent and anaerobic activity). After the end of each exercise, visual-motor response time and accuracy of motor response were assessed. Players' motion was captured by digital video camera. ANOVA indicated no significant difference (p = 0.090) in the accuracy of motor response between the four exercise intensity modes. Practical significance (Z-test = 0.31) was found in visual-motor response time between exercise with dominant involvement of aerobic metabolism, and intense intermittent exercise. A medium size effect (Z-test = 0.34) was also found in visual-motor response time between exercise with dominant involvement of aerobic metabolism and exercise with dominant involvement of anaerobic metabolism, which was confirmed by ANOVA (897.02 ± 57.46 vs. 940.95 ± 71.14; p = 0.002). The results showed that different modes of exercise intensity do not adversely affect the accuracy of motor responses; however, high-intensity exercise has a negative effect on visual-motor response time in comparison to moderate intensity exercise. Key pointsDifferent exercise intensity modes did not affect the accuracy of motor response.Anaerobic, highly intensive short-term exercise significantly decreased the visual-motor response time in comparison with aerobic exercise.Further research should focus on the assessment of VMRT from a player's real - field position view rather than a perspective view.

Effects of exercise intensity and duration on nocturnal heart rate variability and sleep quality.

PubMed

Myllymäki, Tero; Rusko, Heikki; Syväoja, Heidi; Juuti, Tanja; Kinnunen, Marja-Liisa; Kyröläinen, Heikki

2012-03-01

Acute physical exercise may affect cardiac autonomic modulation hours or even days during the recovery phase. Although sleep is an essential recovery period, the information on nocturnal autonomic modulation indicated by heart rate variability (HRV) after different exercises is mostly lacking. Therefore, this study investigated the effects of exercise intensity and duration on nocturnal HR, HRV, HR, and HRV-based relaxation, as well as on actigraphic and subjective sleep quality. Fourteen healthy male subjects (age 36 ± 4 years, maximal oxygen uptake 49 ± 4 ml/kg/min) performed five different running exercises on separate occasions starting at 6 p.m. with HR guidance at home. The effect of intensity was studied with 30 min of exercises at intensities corresponding to HR level at 45% (easy), 60% (moderate) and 75% (vigorous) of their maximal oxygen uptake. The effect of duration was studied with 30, 60, and 90 min of moderate exercises. Increased exercise intensity elevated nocturnal HR compared to control day (p < 0.001), but it did not affect nocturnal HRV. Nocturnal HR was greater after the day with 90- than 30- or 60-min exercises (p < 0.01) or control day (p < 0.001). Nocturnal HRV was lower after the 90-min exercise day compared to control day (p < 0.01). Neither exercise intensity nor duration had any impact on actigraphic or subjective sleep quality. The results suggest that increased exercise intensity and/or duration cause delayed recovery of nocturnal cardiac autonomic modulation, although long exercise duration was needed to induce changes in nocturnal HRV. Increased exercise intensity or duration does not seem to disrupt sleep quality.

The effect of exercise intensity on postresistance exercise hypotension in trained men.

PubMed

Duncan, Michael J; Birch, Samantha L; Oxford, Samuel W

2014-06-01

The occurrence of postresistance exercise hypotension (PEH) after resistance exercise remains unknown. This study examined blood pressure and heart rate (HR) responses to an acute bout of low- and high-intensity resistance exercise, matched for total work, in trained males. Sixteen resistance-trained males (23.1 ± 5.9 years) performed an acute bout of low- (40% of 1 repetition maximum [1RM]) and high-intensity resistance exercise (80% 1RM), matched for total work, separated by 7 days and performed in a counterbalanced order. Systolic blood pressure (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), and HR were assessed before exercise, after completion of each exercise resistance exercise (3 sets of back squat, bench press, and deadlift) and every 10 minutes after resistance exercise for a period of 60 minutes. Results indicated a significant intensity × time interaction for SBP (p = 0.034, partial η(2) = 0.122) and MAP (p = 0.047, partial η(2) = 0.116) whereby SBP and MAP at 50-minute recovery and 60-minute recovery were significantly lower after high-intensity exercise (p = 0.01 for SBP and p = 0.05 for MAP in both cases) compared with low-intensity exercise. There were no significant main effects or interactions in regard to DBP (all p > 0.05). Heart rate data indicated a significant main effect for time (F(9, 135) = 2.479, p = 0.0001, partial η(2) = 0.344). Post hoc multiple comparisons indicated that HR was significantly higher after squat, bench press, and deadlift exercise compared with resting HR and HR at 40-, 50-, and 60-minute recovery (all p = 0.03). The present findings suggest that an acute bout of high intensity, but not low intensity, resistance exercise using compound movements can promote PEH in trained men.

Energy and macronutrient intake in the Midwest Exercise Trial-2 (MET-2)

PubMed Central

Washburn, Richard A.; Honas, Jeff J.; Ptomey, Lauren T.; Mayo, Matthew S.; Lee, Jaehoon; Sullivan, Debra K.; Lambourne, Kathleen; Willis, Erik A.; Donnelly, Joseph E.

2015-01-01

PURPOSE To examined the effect of exercise training over 10 months at 2 levels of energy expenditure on energy and macronutrient intake in a sample of previously sedentary, overweight/obese young adults. METHODS We conducted a 10 month trial in 141 young adults who were randomized to supervised exercise, 5 days•wk−1 at 400 and 600 kcal•session−1, or non-exercise control. Participants were instructed to maintain their usual ad-libitum diets. Energy/macronutrient intake was assessed at baseline, 3.5, 7 and 10 months over 7-day periods of ad libitum eating in a university cafeteria using digital photography. Foods consumed outside the cafeteria were assessed using multiple-pass recalls. RESULTS There were no significant between group differences in absolute energy intake at baseline or any other time point in the total sample or in men. In women, absolute energy intake was significantly greater in the 600 kcal•session−1 group vs. controls at both 3.5 and 7 months. There were no significant between group differences in relative energy intake (kcal•kg•d−1) at any time point in the total sample, men or women. There were no significant within or between group differences of change in absolute or relative energy intake in any of the 3 study groups in the total sample, or in men or women. No clinically relevant changes in macronutrient intake were observed. CONCLUSION Aerobic exercise training does not significantly alter energy or macronutrient intake in overweight and obese young adults. The possibility of a threshold level beyond which increased exercise energy expenditure fails to produce a more negative energy balance, and potential sex differences in the energy intake response to increased levels of exercise are potentially important. PMID:25574796

Objective and subjective measures of exercise intensity during thermo-neutral and hot yoga.

PubMed

Boyd, Corinne N; Lannan, Stephanie M; Zuhl, Micah N; Mora-Rodriguez, Ricardo; Nelson, Rachael K

2018-04-01

While hot yoga has gained enormous popularity in recent years, owing in part to increased environmental challenge associated with exercise in the heat, it is not clear whether hot yoga is more vigorous than thermo-neutral yoga. Therefore, the aim of this study was to determine objective and subjective measures of exercise intensity during constant intensity yoga in a hot and thermo-neutral environment. Using a randomized, crossover design, 14 participants completed 2 identical ∼20-min yoga sessions in a hot (35.3 ± 0.8 °C; humidity: 20.5% ± 1.4%) and thermo-neutral (22.1 ± 0.2 °C; humidity: 27.8% ± 1.6%) environment. Oxygen consumption and heart rate (HR) were recorded as objective measures (percentage of maximal oxygen consumption and percentage of maximal HR (%HRmax)) and rating of perceived exertion (RPE) was recorded as a subjective measure of exercise intensity. There was no difference in exercise intensity based on percentage of maximal oxygen consumption during hot versus thermo-neutral yoga (30.9% ± 2.3% vs. 30.5% ± 1.8%, p = 0.68). However, exercise intensity was significantly higher during hot versus thermo-neutral yoga based on %HRmax (67.0% ± 2.3% vs. 60.8% ± 1.9%, p = 0.01) and RPE (12 ± 1 vs. 11 ± 1, p = 0.04). According to established exercise intensities, hot yoga was classified as light-intensity exercise based on percentage of maximal oxygen consumption but moderate-intensity exercise based on %HRmax and RPE while thermo-neutral yoga was classified as light-intensity exercise based on percentage of maximal oxygen uptake, %HRmax, and RPE. Despite the added hemodynamic stress and perception that yoga is more strenuous in a hot environment, we observed similar oxygen consumption during hot versus thermo-neutral yoga, classifying both exercise modalities as light-intensity exercise.

Decline in Executive Control during Acute Bouts of Exercise as a Function of Exercise Intensity and Fitness Level

ERIC Educational Resources Information Center

Labelle, Veronique; Bosquet, Laurent; Mekary, Said; Bherer, Louis

2013-01-01

Studies on the effects of acute bouts of cardiovascular exercise on cognitive performances show contradictory findings due to methodological differences (e.g., exercise intensity, cognitive function assessed, participants' aerobic fitness level, etc.). The present study assessed the acute effect of exercise intensity on cognition while controlling…

Study in Parkinson Disease of Exercise (SPARX): Translating high-intensity exercise from animals to humans

PubMed Central

Moore, Charity G.; Schenkman, Margaret; Kohrt, Wendy M.; Delitto, Anthony; Hall, Deborah A.; Corcos, Daniel

2013-01-01

A burgeoning literature suggests that exercise has a therapeutic benefit in persons with Parkinson disease (PD) and in animal models of PD, especially when animals exercise at high intensity. If exercise is to be prescribed as “first-line” or “add-on” therapy in patients with PD, we must demonstrate its efficacy and dose-response effects through testing phases similar to those used in the testing of pharmacologic agents. The SPARX Trial is a multicenter, randomized, controlled, single-blinded, Phase II study that we designed to test the feasibility of using high-intensity exercise to modify symptoms of PD and to simultaneously test the nonfutility of achieving a prespecified change in patients’ motor scores on the Unified Parkinson Disease Rating Scale (UPDRS). The trial began in May 2102 and is in the process of screening, enrolling, and randomly assigning 126 patients with early-stage PD to 1 of 3 groups: usual care (wait-listed controls), moderate-intensity exercise (4 days/week at 60%–65% maximal heart rate [HRmax]), or high-intensity exercise (4 days/week at 80%–85% HRmax). At 6-month follow-up, the trial is randomly reassigning usual care participants to a moderate-intensity or high-intensity exercise group for the remaining 6 months. The goals of the Phase II trial are to determine if participants can exercise at moderate and high intensities; to determine if either exercise yields benefits consistent with meaningful clinical change (nonfutility); and to document safety and attrition. The advantage of using a non-futility approach allows us to efficiently determine if moderate- or high-intensity exercise warrants further large-scale investigation in PD. PMID:23770108

High-intensity exercise interventions in cancer survivors: a systematic review exploring the impact on health outcomes.

PubMed

Toohey, Kellie; Pumpa, Kate; McKune, Andrew; Cooke, Julie; Semple, Stuart

2018-01-01

There is an increasing body of evidence underpinning high-intensity exercise as an effective and time-efficient intervention for improving health in cancer survivors. The aim of this study was to, (1) evaluate the efficacy and (2) the safety of high-intensity exercise interventions in improving selected health outcomes in cancer survivors. Design Systematic review. Data sources Google Scholar and EBSCO, CINAHL Plus, Computers and Applied Sciences Complete, Health Source-Consumer Edition, Health Source: Nursing/Academic Edition, MEDLINE, Web of Science and SPORTDiscuss from inception up until August 2017. Eligibility criteria Randomized controlled trials of high-intensity exercise interventions in cancer survivors (all cancer types) with health-related outcome measures. The guidelines adopted for this review were the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The search returned 447 articles, of which nine articles (n = 531 participants mean, age 58 ± 9.5 years) met the eligibility criteria. Exercise interventions of between 4 and 18 weeks consisting of high-intensity interval bouts of up to 4-min were compared with a continuous moderate intensity (CMIT) intervention or a control group. High-intensity exercise interventions elicited significant improvements in VO 2 max, strength, body mass, body fat and hip and waist circumference compared with CMIT and/or control groups. The studies reviewed showed low risk in participating in supervised high-intensity exercise interventions. Mixed mode high-intensity interventions which included both aerobic and resistance exercises were most effective improving the aerobic fitness levels of cancer survivors by 12.45-21.35%, from baseline to post-intervention. High-intensity exercise interventions improved physical and physiological health-related outcome measures such as cardiovascular fitness and strength in cancer survivors. Given that high-intensity exercise sessions require a shorter time commitment, it may be a useful modality to improve health outcomes in those who are time poor. The risk of adverse events associated with high-intensity exercise was low.

Effects of aerobic training intensity on resting, exercise and post-exercise blood pressure, heart rate and heart-rate variability.

PubMed

Cornelissen, V A; Verheyden, B; Aubert, A E; Fagard, R H

2010-03-01

We aimed to investigate the effects of endurance training intensity (1) on systolic blood pressure (SBP) and heart rate (HR) at rest before exercise, and during and after a maximal exercise test; and (2) on measures of HR variability at rest before exercise and during recovery from the exercise test, in at least 55-year-old healthy sedentary men and women. A randomized crossover study comprising three 10-week periods was performed. In the first and third period, participants exercised at lower or higher intensity (33% or 66% of HR reserve) in random order, with a sedentary period in between. Training programmes were identical except for intensity, and were performed under supervision thrice for 1 h per week. The results show that in the three conditions, that is, at rest before exercise, during exercise and during recovery, we found endurance training at lower and higher intensity to reduce SBP significantly (P<0.05) and to a similar extent. Further, SBP during recovery was, on average, not lower than at rest before exercise, and chronic endurance training did not affect the response of SBP after an acute bout of exercise. The effect of training on HR at rest, during exercise and recovery was more pronounced (P<0.05) with higher intensity. Finally, endurance training had no significant effect on sympathovagal balance. In conclusion, in participants at higher age, both training programmes exert similar effects on SBP at rest, during exercise and during post-exercise recovery, whereas the effects on HR are more pronounced after higher intensity training.

Cardiac Autonomic Responses during Exercise and Post-exercise Recovery Using Heart Rate Variability and Systolic Time Intervals-A Review.

PubMed

Michael, Scott; Graham, Kenneth S; Davis, Glen M

2017-01-01

Cardiac parasympathetic activity may be non-invasively investigated using heart rate variability (HRV), although HRV is not widely accepted to reflect sympathetic activity. Instead, cardiac sympathetic activity may be investigated using systolic time intervals (STI), such as the pre-ejection period. Although these autonomic indices are typically measured during rest, the "reactivity hypothesis" suggests that investigating responses to a stressor (e.g., exercise) may be a valuable monitoring approach in clinical and high-performance settings. However, when interpreting these indices it is important to consider how the exercise dose itself (i.e., intensity, duration, and modality) may influence the response. Therefore, the purpose of this investigation was to review the literature regarding how the exercise dosage influences these autonomic indices during exercise and acute post-exercise recovery. There are substantial methodological variations throughout the literature regarding HRV responses to exercise, in terms of exercise protocols and HRV analysis techniques. Exercise intensity is the primary factor influencing HRV, with a greater intensity eliciting a lower HRV during exercise up to moderate-high intensity, with minimal change observed as intensity is increased further. Post-exercise, a greater preceding intensity is associated with a slower HRV recovery, although the dose-response remains unclear. A longer exercise duration has been reported to elicit a lower HRV only during low-moderate intensity and when accompanied by cardiovascular drift, while a small number of studies have reported conflicting results regarding whether a longer duration delays HRV recovery. "Modality" has been defined multiple ways, with limited evidence suggesting exercise of a greater muscle mass and/or energy expenditure may delay HRV recovery. STI responses during exercise and recovery have seldom been reported, although limited data suggests that intensity is a key determining factor. Concurrent monitoring of HRV and STI may be a valuable non-invasive approach to investigate autonomic stress reactivity; however, this integrative approach has not yet been applied with regards to exercise stressors.

Cardiac Autonomic Responses during Exercise and Post-exercise Recovery Using Heart Rate Variability and Systolic Time Intervals—A Review

PubMed Central

Michael, Scott; Graham, Kenneth S.; Davis, Glen M.

2017-01-01

Cardiac parasympathetic activity may be non-invasively investigated using heart rate variability (HRV), although HRV is not widely accepted to reflect sympathetic activity. Instead, cardiac sympathetic activity may be investigated using systolic time intervals (STI), such as the pre-ejection period. Although these autonomic indices are typically measured during rest, the “reactivity hypothesis” suggests that investigating responses to a stressor (e.g., exercise) may be a valuable monitoring approach in clinical and high-performance settings. However, when interpreting these indices it is important to consider how the exercise dose itself (i.e., intensity, duration, and modality) may influence the response. Therefore, the purpose of this investigation was to review the literature regarding how the exercise dosage influences these autonomic indices during exercise and acute post-exercise recovery. There are substantial methodological variations throughout the literature regarding HRV responses to exercise, in terms of exercise protocols and HRV analysis techniques. Exercise intensity is the primary factor influencing HRV, with a greater intensity eliciting a lower HRV during exercise up to moderate-high intensity, with minimal change observed as intensity is increased further. Post-exercise, a greater preceding intensity is associated with a slower HRV recovery, although the dose-response remains unclear. A longer exercise duration has been reported to elicit a lower HRV only during low-moderate intensity and when accompanied by cardiovascular drift, while a small number of studies have reported conflicting results regarding whether a longer duration delays HRV recovery. “Modality” has been defined multiple ways, with limited evidence suggesting exercise of a greater muscle mass and/or energy expenditure may delay HRV recovery. STI responses during exercise and recovery have seldom been reported, although limited data suggests that intensity is a key determining factor. Concurrent monitoring of HRV and STI may be a valuable non-invasive approach to investigate autonomic stress reactivity; however, this integrative approach has not yet been applied with regards to exercise stressors. PMID:28611675

Coenzyme Q10 supplementation downregulates the increase of monocytes expressing toll-like receptor 4 in response to 6-day intensive training in kendo athletes.

PubMed

Shimizu, Kazuhiro; Kon, Michihiro; Tanimura, Yuko; Hanaoka, Yukichi; Kimura, Fuminori; Akama, Takao; Kono, Ichiro

2015-06-01

This study examined changes in toll-like receptor 4 (TLR-4)-expressing monocytes and lymphocyte subpopulations in response to continuous intensive exercise training in athletes, as well as the effect of coenzyme Q10 (CoQ10) supplementation on these changes. Eighteen male elite kendo athletes in Japan were randomly assigned to a CoQ10-supplementation group (n = 9) or a placebo-supplementation group (n = 9) using a double-blind method. Subjects in the CoQ10 group took 300 mg CoQ10 per day for 20 days. Subjects in the placebo group took the same dosage of placebo. All subjects practiced kendo 5.5 h per day for 6 consecutive days during the study period. Blood samples were collected 2 weeks before training, on the first day (day 1), third day (day 3), and fifth day of training (day 5), and 1 week after the training period (post-training) to ascertain TLR-4(+)/CD14(+) monocyte and lymphocyte subpopulations (CD3(+), CD4(+), CD8(+), CD28(+)/CD4(+), CD28(+)/CD8(+), and CD56(+)/CD3(-) cells) using flow cytometry analysis. The group × time interaction for TLR-4(+)/CD14(+) cells did not reach significance (p = 0.08). Within the CoQ10 group, the absolute number of TLR-4(+)/CD14(+) cells was significantly higher only at day 5. The placebo group showed a significant increase in the absolute number of TLR-4(+)/CD14(+) cells at day 3, day 5, and post-training (p < 0.05). There was no significant group × time interaction for any lymphocyte subpopulation. CD3(+), CD8(+), and CD56(+)/CD3(-) cells were significantly reduced at day 3 in both groups (p < 0.05). In conclusion, CoQ10 supplementation might downregulate the increase of TLR-4-expressing monocytes in response to continuous strenuous exercise training in kendo athletes.

Impaired modulation of postjunctional α1 - but not α2 -adrenergic vasoconstriction in contracting forearm muscle of postmenopausal women.

PubMed

Kruse, Nicholas T; Hughes, William E; Ueda, Kenichi; Hanada, Satoshi; Feider, Andrew J; Iwamoto, Erika; Bock, Joshua M; Casey, Darren P

2018-04-30

Contraction-mediated blunting of postjunctional α-adrenergic vasoconstriction (functional sympatholysis) is attenuated in skeletal muscle of ageing males, brought on by altered postjunctional α 1 - and α 2 -adrenergic receptor sensitivity. The extent to which postjunctional α-adrenergic vasoconstriction occurs in the forearms at rest and during exercise in postmenopausal women remains unknown. The novel findings indicate that contraction-mediated blunting of α 1 - (via intra-arterial infusion of phenylephrine) but not α 2 -adrenergic (via intra-arterial infusion of dexmedetomidine) vasoconstriction was attenuated in postmenopausal women compared to young women. Additional important findings revealed that postjunctional α-adrenergic vasoconstrictor responsiveness at rest does not appear to be affected by age in women. Collectively, these results contribute to our understanding of local neurovascular control at rest and during exercise with age in women. Contraction-mediated blunting of postjunctional α-adrenergic vasoconstriction (functional sympatholysis) is attenuated in older males; however, direct confirmation of this effect remains unknown in postmenopausal women (PMW). The present study examined whether PMW exhibit augmented postjunctional α-adrenergic receptor vasoconstriction at rest and during forearm exercise compared to young women (YW). Eight YW (24 ± 1 years) and eight PMW (65 ± 1 years) completed a series of randomized experimental trials: (1) at rest, (2) under high flow (adenosine infusion) conditions and (3) during 6 min of forearm exercise at relative (20% of maximum) and absolute (7 kg) intensities. Phenylephrine (α 1 -agonist) or dexmedetomidine (α 2 -agonist) was administered during the last 3 min of each trial to elicit α-adrenergic vasoconstriction. Forearm vascular conductance (FVC) was calculated from blood flow and blood pressure. Vasoconstrictor responsiveness was identified as the change in FVC (%) during α-adrenergic agonist infusions from baseline (resting trial) or from steady-state conditions (high flow and exercise trials). During resting and high flow trials, the %FVC during α 1 - and α 2 -agonist stimulation was similar between YW and PMW. During exercise, α 1 -mediated vasoconstriction was blunted in YW vs. PMW at relative (-6 ± 2% vs. -15 ± 3%) and absolute (-4 ± 2% vs. -14 ± 5%) workloads, such that blood flow and FVC were lower in PMW (P < 0.05 for all). Conversely, α 2 -mediated vasoconstriction was similar between YW and PMW at relative (-22 ± 3% vs. -22 ± 4%; P > 0.05) and absolute (-19 ± 3% vs. -18 ± 4%; P > 0.05) workloads. Collectively, these findings demonstrate that despite similar α-adrenergic vasoconstrictor responsiveness at rest, PMW have a decreased ability to attenuate α 1 -adrenergic vasoconstriction in contracting skeletal muscle. © 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.

Psychobiological Responses to Preferred and Prescribed Intensity Exercise in Major Depressive Disorder.

PubMed

Meyer, Jacob D; Ellingson, Laura D; Koltyn, Kelli F; Stegner, Aaron J; Kim, Jee-Seon; Cook, Dane B

2016-11-01

Exercise acutely improves mood in major depressive disorder (MDD). However, it is unknown whether benefits differ depending on whether exercise intensity is self-selected or prescribed. This study aimed to compare psychological and biological responses to preferred and prescribed steady-state exercise intensities to a patient-selected preferred intensity. Female adults (N = 24, age = 38.6 ± 14.0 yr) diagnosed with MDD completed four 30-min sessions of cycling exercise at three prescribed intensities (RPE of 11, 13, and 15) and one session with a self-selected intensity (preferred). Order was randomized and counterbalanced. Depressed mood (DM) was evaluated before, 10 min, and 30 min postexercise using the Profile of Mood States. Serum brain-derived neurotrophic factor (BDNF) was measured before and within 10 min postexercise. Changes in BDNF and DM for the preferred session were compared with the following prescribed sessions: 1) performed at the most similar intensity (matched on RPE; closest) and 2) with the greatest improvement in DM (greatest). Compared with the preferred session, improvement in DM was significantly larger after the greatest session (30 min postexercise: -11.8 ± 7.4 vs -3.4 ± 4.8), and the BDNF response was significantly greater after the closest session (5.4 ± 6.9 vs -1.4 ± 9.8 ng·mL). Permitting patients to select their own exercise intensity did not maximize improvements in mood. Further, preferred intensity exercise was also associated with a smaller BDNF response. Overall, the results suggest that exercise undertaken to improve mood should be prescribed on an individual basis in MDD and not necessarily based on the patient's preferred intensity. Clinicians, psychologists, and other practitioners should consider providing clear exercise intensity recommendations for symptom management in depression rather than allowing patients to self-select their intensity.

Optimizing the "priming" effect: influence of prior exercise intensity and recovery duration on O2 uptake kinetics and severe-intensity exercise tolerance.

PubMed

Bailey, Stephen J; Vanhatalo, Anni; Wilkerson, Daryl P; Dimenna, Fred J; Jones, Andrew M

2009-12-01

It has been suggested that a prior bout of high-intensity exercise has the potential to enhance performance during subsequent high-intensity exercise by accelerating the O(2) uptake (Vo(2)) on-response. However, the optimal combination of prior exercise intensity and subsequent recovery duration required to elicit this effect is presently unclear. Eight male participants, aged 18-24 yr, completed step cycle ergometer exercise tests to 80% of the difference between the preestablished gas exchange threshold and maximal Vo(2) (i.e., 80%Delta) after no prior exercise (control) and after six different combinations of prior exercise intensity and recovery duration: 40%Delta with 3 min (40-3-80), 9 min (40-9-80), and 20 min (40-20-80) of recovery and 70%Delta with 3 min (70-3-80), 9 min (70-9-80), and 20 min (70-20-80) of recovery. Overall Vo(2) kinetics were accelerated relative to control in all conditions except for 40-9-80 and 40-20-80 conditions as a consequence of a reduction in the Vo(2) slow component amplitude; the phase II time constant was not significantly altered with any prior exercise/recovery combination. Exercise tolerance at 80%Delta was improved by 15% and 30% above control in the 70-9-80 and 70-20-80 conditions, respectively, but was impaired by 16% in the 70-3-80 condition. Prior exercise at 40%Delta did not significantly influence exercise tolerance regardless of the recovery duration. These data demonstrate that prior high-intensity exercise ( approximately 70%Delta) can enhance the tolerance to subsequent high-intensity exercise provided that it is coupled with adequate recovery duration (>or=9 min). This combination presumably optimizes the balance between preserving the effects of prior exercise on Vo(2) kinetics and providing sufficient time for muscle homeostasis (e.g., muscle phosphocreatine and H(+) concentrations) to be restored.

The feasibility and effectiveness of high-intensity boxing training versus moderate-intensity brisk walking in adults with abdominal obesity: a pilot study.

PubMed

Cheema, Birinder S; Davies, Timothy B; Stewart, Matthew; Papalia, Shona; Atlantis, Evan

2015-01-01

High-intensity interval training (HIIT) performed on exercise cycle or treadmill is considered safe and often more beneficial for fat loss and cardiometabolic health than moderate-intensity continuous training (MICT). The aim of this pilot study was to assess the feasibility and effectiveness of a 12-week boxing training (HIIT) intervention compared with an equivalent dose of brisk walking (MICT) in obese adults. Men and women with abdominal obesity and body mass index >25 kg/m(2) were randomized to either a boxing group or a brisk walking (control) group for 12 weeks. Each group engaged in 4 training sessions per week, equated for total physical activity. Feasibility outcomes included recruitment rates, assessment of training intensities, adherence and adverse events. Effectiveness was assessed pre and post intervention via pertinent obesity-, cardiovascular-, and health-related quality of life (HRQoL) outcomes. Nineteen individuals expressed an interest and 63% (n = 12) consented. Recruitment was slower than anticipated (1.3 participants/week). The boxing group trained at a significantly higher intensity each week versus the brisk walking group (p < 0.05). Two participants in the boxing group experienced an adverse event; both continued to exercise with modifications to the exercise program. No other adverse events were noted. The boxing group attended more sessions (79% vs. 55%) and had a lower attrition rate (n = 0 vs. n = 2) than the walking group. Analysis of covariance revealed that the boxing group significantly improved body fat percentage (p = 0.047), systolic blood pressure (p = 0.026), augmentation index (AIx; p < 0.001), absolute VO2max (p = 0.015), and Physical Functioning (p = 0.042) and Vitality (p = 0.024) domains of HRQoL over time. The walking group did not improve any clinical outcomes, and experienced a worsening of Vitality (p = 0.043). Boxing training (HIIT) in adults with abdominal obesity is feasible and may elicit a better therapeutic effect on obesity, cardiovascular, and HRQoL outcomes than an equivalent dose of brisk walking (MICT). Robustly designed randomized controlled trials are required to confirm these findings and inform clinical guidelines and practice for obesity treatment. ACTRN12615000007538.

Oxygen Uptake Kinetics Is Slower in Swimming Than Arm Cranking and Cycling during Heavy Intensity

PubMed Central

Sousa, Ana; Borrani, Fabio; Rodríguez, Ferran A.; Millet, Grégoire P.

2017-01-01

Oxygen uptake (V·O2) kinetics has been reported to be influenced by the activity mode. However, only few studies have compared V·O2 kinetics between activities in the same subjects in which they were equally trained. Therefore, this study compared the V·O2 kinetics response to swimming, arm cranking, and cycling within the same group of subjects within the heavy exercise intensity domain. Ten trained male triathletes (age 23.2 ± 4.5 years; height 180.8 ± 8.3 cm; weight 72.3 ± 6.6 kg) completed an incremental test to exhaustion and a 6-min heavy constant-load test in the three exercise modes in random order. Gas exchange was measured by a breath-by-breath analyzer and the on-transient V·O2 kinetics was modeled using bi-exponential functions. V·O2peak was higher in cycling (65.6 ± 4.0 ml·kg−1·min−1) than in arm cranking or swimming (48.7 ± 8.0 and 53.0 ± 6.7 ml·kg−1·min−1; P < 0.01), but the V·O2 kinetics were slower in swimming (τ1 = 31.7 ± 6.2 s) than in arm cranking (19.3 ± 4.2 s; P = 0.001) and cycling (12.4 ± 3.7 s; P = 0.001). The amplitude of the primary component was lower in both arm cranking and swimming (21.9 ± 4.7 and 28.4 ± 5.1 ml·kg−1·min−1) compared with cycling (39.4 ± 4.1 ml·kg−1·min−1; P = 0.001). Although the gain of the primary component was higher in arm cranking compared with cycling (15.3 ± 4.2 and 10.7 ± 1.3 ml·min−1·W−1; P = 0.02), the slow component amplitude, in both absolute and relative terms, did not differ between exercise modes. The slower V·O2 kinetics during heavy-intensity swimming is exercise-mode dependent. Besides differences in muscle mass and greater type II muscle fibers recruitment, the horizontal position adopted and the involvement of trunk and lower-body stabilizing muscles could be additional mechanisms that explain the differences between exercise modalities. PMID:28919863

Preferred Exertion across Three Common Modes of Exercise Training.

ERIC Educational Resources Information Center

Glass, Stephen C.; Chvala, Angela M.

2001-01-01

Examined the influence of exercise mode on self-selected exercise intensities. Participants performed three types of intensity tests. Researchers collected data on VO2 values continuously and recorded 1-minute averages several times for each submaximal test. Participants allowed to self-select exercise intensity chose work rates within the…

The Effects of Acute Exercise on Memory and Brain-Derived Neurotrophic Factor (BDNF).

PubMed

Etnier, Jennifer L; Wideman, Laurie; Labban, Jeffrey D; Piepmeier, Aaron T; Pendleton, Daniel M; Dvorak, Kelly K; Becofsky, Katie

2016-08-01

Acute exercise benefits cognition, and some evidence suggests that brain-derived neurotrophic factor (BDNF) plays a role in this effect. The purpose of this study was to explore the dose-response relationship between exercise intensity, memory, and BDNF. Young adults completed 3 exercise sessions at different intensities relative to ventilator threshold (Vt) (VO 2max , Vt - 20%, Vt + 20%). For each session, participants exercised for approximately 30 min. Following exercise, they performed the Rey Auditory Verbal Learning Test (RAVLT) to assess short-term memory, learning, and long-term memory recall. Twenty-four hours later, they completed the RAVLT recognition trial, which provided another measure of long-term memory. Blood was drawn before exercise, immediately postexercise, and after the 30-min recall test. Results indicated that long-term memory as assessed after the 24-hr delay differed as a function of exercise intensity with the largest benefits observed following maximal intensity exercise. BDNF data showed a significant increase in response to exercise; however, there were no differences relative to exercise intensity and there were no significant associations between BDNF and memory. Future research is warranted so that we can better understand how to use exercise to benefit cognitive performance.

High-intensity exercise training for the prevention of type 2 diabetes mellitus.

PubMed

Rynders, Corey A; Weltman, Arthur

2014-02-01

Aerobic exercise training and diet are recommended for the primary prevention of type 2 diabetes mellitus and cardiovascular disease. The American Diabetes Association (ADA) recommends that adults with prediabetes engage in ≥ 150 minutes per week of moderate activity and target a 7% weight loss. However, traditional moderate-intensity (MI) exercise training programs are often difficult to sustain for prediabetic adults; a commonly cited barrier to physical activity in this population is the "lack of time" to exercise. When matched for total energy expenditure, high-intensity (HI) exercise training has a lower overall time commitment compared with traditional low-intensity (LI) or MI exercise training. Several recent studies comparing HI exercise training with LI and MI exercise training reported that HI exercise training improves skeletal muscle metabolic control and cardiovascular function in a comparable and/or superior way relative to LI and MI exercise training. Although patients can accrue all exercise benefits by performing LI or MI activities such as walking, HI activities represent a time-efficient alternative to meeting physical activity guidelines. High-intensity exercise training is a potent tool for improving cardiometabolic risk for prediabetic patients with limited time and may be prescribed when appropriate.

Cancer and Exercise: Warburg Hypothesis, Tumour Metabolism and High-Intensity Anaerobic Exercise.

PubMed

Hofmann, Peter

2018-01-31

There is ample evidence that regular moderate to vigorous aerobic physical activity is related to a reduced risk for various forms of cancer to suggest a causal relationship. Exercise is associated with positive changes in fitness, body composition, and physical functioning as well as in patient-reported outcomes such as fatigue, sleep quality, or health-related quality of life. Emerging evidence indicates that exercise may also be directly linked to the control of tumour biology through direct effects on tumour-intrinsic factors. Beside a multitude of effects of exercise on the human body, one underscored effect of exercise training is to target the specific metabolism of tumour cells, namely the Warburg-type highly glycolytic metabolism. Tumour metabolism as well as the tumour⁻host interaction may be selectively influenced by single bouts as well as regularly applied exercise, dependent on exercise intensity, duration, frequency and mode. High-intensity anaerobic exercise was shown to inhibit glycolysis and some studies in animals showed that effects on tumour growth might be stronger compared with moderate-intensity aerobic exercise. High-intensity exercise was shown to be safe in patients; however, it has to be applied carefully with an individualized prescription of exercise.

Effects of treadmill exercise intensity on spatial working memory and long-term memory in rats.

PubMed

Wang, Xiao-Qin; Wang, Gong-Wu

2016-03-15

Moderate exercise promotes learning and memory. Most studies mainly focused on memory exercise effects of in the ageing and patients. There is lack of quantitative research about effect of regular exercise intensity on different memory types in normal subjects. Present study investigated the effects of different intensities of treadmill exercise on working memory and long-term memory. Fifty female Wistar rats were trained by T-maze delayed spatial alternation (DSA) task with 3 delays (10s, 60s and 300s). Then they got a 30min treadmill exercise for 30days in 4 intensities (control, 0m/min; lower, 15m/min; middle, 20m/min, and higher, 30m/min). Then animals were tested in DSA, passive avoidance and Morris water maze tasks. 1. Exercise increased the neuronal density of hippocampal subregions (CA1, CA3 and dentate gyrus) vs. naïve/control. 2. In DSA task, all groups have similar baseline, lower intensity improved 10s delay accuracy vs. baseline/control; middle and higher intensities improved 300s delay accuracy vs. baseline/control. 3. In water maze learning, all groups successfully found the platform, but middle intensity improved platform field crossing times vs. control in test phase. Present results suggested that treadmill exercise can improve long-term spatial memory and working memory; lower intensity benefits to short-term delayed working memory, and middle or higher intensity benefits to long-term delayed working memory. There was an inverted U dose-effect relationship between exercise intensity and memory performance, but exercise -working memory effect was impacted by delay duration. Copyright © 2016 Elsevier Inc. All rights reserved.

Does Physical Loading Affect The Speed and Accuracy of Tactical Decision-Making in Elite Junior Soccer Players?

PubMed Central

Frýbort, Pavel; Kokštejn, Jakub; Musálek, Martin; Süss, Vladimír

2016-01-01

A soccer player’s capability to control and manage his behaviour in a game situation is a prerequisite, reflecting not only swift and accurate tactical decision-making, but also prompt implementation of a motor task during intermittent exercise conditions. The purpose of this study was to analyse the relationship between varying exercise intensity and the visual-motor response time and the accuracy of motor response in an offensive game situation in soccer. The participants (n = 42) were male, semi-professional, soccer players (M age 18.0 ± 0.9 years) and trained five times a week. Each player performed four different modes of exercise intensity on the treadmill (motor inactivity, aerobic, intermittent and anaerobic activity). After the end of each exercise, visual-motor response time and accuracy of motor response were assessed. Players’ motion was captured by digital video camera. ANOVA indicated no significant difference (p = 0.090) in the accuracy of motor response between the four exercise intensity modes. Practical significance (Z-test = 0.31) was found in visual-motor response time between exercise with dominant involvement of aerobic metabolism, and intense intermittent exercise. A medium size effect (Z-test = 0.34) was also found in visual-motor response time between exercise with dominant involvement of aerobic metabolism and exercise with dominant involvement of anaerobic metabolism, which was confirmed by ANOVA (897.02 ± 57.46 vs. 940.95 ± 71.14; p = 0.002). The results showed that different modes of exercise intensity do not adversely affect the accuracy of motor responses; however, high-intensity exercise has a negative effect on visual-motor response time in comparison to moderate intensity exercise. Key points Different exercise intensity modes did not affect the accuracy of motor response. Anaerobic, highly intensive short-term exercise significantly decreased the visual-motor response time in comparison with aerobic exercise. Further research should focus on the assessment of VMRT from a player’s real - field position view rather than a perspective view. PMID:27274671

Hormetic effects by exercise on hippocampal neurogenesis with glucocorticoid signaling

PubMed Central

Okamoto, Masahiro; Yamamura, Yuhei; Liu, Yu-Fan; Min-Chul, Lee; Matsui, Takashi; Shima, Takeru; Soya, Mariko; Takahashi, Kanako; Soya, Shingo; McEwen, Bruce S.; Soya, Hideaki

2015-01-01

Abstract Exercise enhances adult hippocampal neurogenesis (AHN), although the exact nature of how this happens remains controversial. The beneficial effects of exercise vary depending upon the exercise condition, especially intensity. Most animal studies, however, have used wheel running, which only evaluates running distance (exercise volume) and does not consider intensity. In our rat model, we have found that exercise-induced neurogenesis varies depending on the intensity of the exercise and have found that exercise-enhanced neurogenesis is more pronounced with mild exercise than with moderate and/or intense exercise. This may be due, at least in part, to increased glucocorticoid (CORT) secretion. To test this hypothesis, we used our special exercise model in mice, with and without a stress response, based on the lactate threshold (LT) in which moderate exercise above the LT increases lactate and adrenocorticotropic hormone (ACTH) release, while mild exercise does not. Adult male C57BL/6J mice were subjected to two weeks of exercise training and AHN was measured with a 5-Bromo-2-deoxyuridine (BrdU) pre-injection and immunohistochemistry. The role of glucocorticoid signaling was examined using intrapertioneal injections of antagonists for the glucocorticoid receptor (GR), mifepristone, and the mineralocorticoid receptor (MR), spironolactone. We found that, while mild exercise increased AHN without elevating CORT blood levels, both MR and GR antagonists abolished mild-exercise-induced AHN, but did not affect AHN under intense exercise. This suggests a facilitative, permissive role of glucocorticoid and mineralocorticoid receptors in AHN during mild exercise (234/250)

The Effect of Music on Exercise Intensity among Children with Autism Spectrum Disorder: A Pilot Study

PubMed Central

Woodman, Ashley C.; Breviglia, Emily; Mori, Yumiko; Golden, Rebecca; Maina, John; Wisniewski, Hannah

2018-01-01

Children with autism spectrum disorder (ASD) are at risk for obesity, commonly have sleep disorders, and exhibit stereotypic behaviors that disrupt their learning. Vigorous levels of exercise have been shown to ameliorate these issues in children with ASD, but little research exists to provide techniques for motivating children with ASD to engage in exercise. The present study examined the effect of music on exercise intensity in a group of 13 elementary school students with ASD. Data were collected across six days during structured (e.g., verbal and physical prompts) and unstructured (e.g., minimal prompting) exercise periods. During these exercise periods, three music conditions were randomized: no music, slow-tempo music, and fast-tempo music. Exercise intensity, measured in Metabolic Equivalent of Tasks by triaxial accelerometers, was greatest during the structured exercise periods and during the slow music condition. Student characteristics moderated the impact of music condition on exercise intensity, such that students with high levels of adaptive behavior or lower levels of maladaptive behavior displayed greater exercise intensity during the fast music condition. PMID:29495354

Physiological Tolerance to Uncompensable Heat Stress: Effects of Exercise Intensity, Protective Clothing, and Climate

DTIC Science & Technology

1994-01-01

Physiological tolerance to uncompensable heat stress: effects of exercise intensity, protective clothing , and climate SCOTT J. MONTAIN, MICHAEL N...effects of exercise 26), there remains little information to predict the inci- intensity, protective clothing , and climate. J. AppL PhysioL dence of...that pre- exercise intensity, protective clothing level, and climate on dict the physiological responses and work capability dur- physiological tolerance

The relation between exercise and glaucoma in a South Korean population-based sample.

PubMed

Lin, Shuai-Chun; Wang, Sophia Y; Pasquale, Louis R; Singh, Kuldev; Lin, Shan C

2017-01-01

To investigate the association between exercise and glaucoma in a South Korean population-based sample. Population-based, cross-sectional study. A total of 11,246 subjects, 40 years and older who underwent health care assessment as part of the 2008-2011 Korean National Health and Nutrition Examination Survey. Variables regarding the duration (total minutes per week), frequency (days per week), and intensity of exercise (vigorous, moderate exercise and walking) as well as glaucoma prevalence were ascertained for 11,246 survey participants. Demographic, comorbidity, and health-related behavior information was obtained via interview. Multivariable logistic regression analyses were performed to determine the association between the exercise-related parameters and odds of a glaucoma diagnosis. Glaucoma defined by International Society for Geographical and Epidemiological Ophthalmology criteria. Overall, 336 (2.7%) subjects met diagnostic criteria for glaucomatous disease. After adjustment for potential confounding variables, subjects engaged in vigorous exercise 7 days per week had higher odds of having glaucoma compared with those exercising 3 days per week (Odds Ratio [OR] 3.33, 95% confidence interval [CI] 1.16-9.54). High intensity of exercise, as categorized by the guidelines of the American College of Sports Medicine (ACSM), was also associated with greater glaucoma prevalence compared with moderate intensity of exercise (OR 1.55, 95% CI 1.03-2.33). There was no association between other exercise parameters including frequency of moderate exercise, walking, muscle strength exercise, flexibility training, or total minutes of exercise per week, and the prevalence of glaucoma. In sub-analyses stratifying by gender, the association between frequency of vigorous exercise 7 days per week and glaucoma diagnosis remained significant in men (OR 6.05, 95% CI 1.67-21.94) but not in women (OR 0.96 95% CI: 0.23-3.97). A U-shaped association between exercise intensity and glaucoma prevalence was noted in men (OR 1.71, 95% CI 1.09-2.69 for low intensity versus moderate intensity; OR 2.19, 95% CI 1.25-3.85 for high intensity versus moderate intensity). In a South Korean population sample, daily vigorous exercise was associated with higher glaucoma prevalence. In addition, the intensity of exercise was positively associated with glaucoma diagnosis in men but not women.

The relation between exercise and glaucoma in a South Korean population-based sample

PubMed Central

Lin, Shuai-Chun; Wang, Sophia Y.; Pasquale, Louis R.; Singh, Kuldev; Lin, Shan C.

2017-01-01

Purpose To investigate the association between exercise and glaucoma in a South Korean population-based sample. Design Population-based, cross-sectional study. Participants A total of 11,246 subjects, 40 years and older who underwent health care assessment as part of the 2008–2011 Korean National Health and Nutrition Examination Survey. Methods Variables regarding the duration (total minutes per week), frequency (days per week), and intensity of exercise (vigorous, moderate exercise and walking) as well as glaucoma prevalence were ascertained for 11,246 survey participants. Demographic, comorbidity, and health-related behavior information was obtained via interview. Multivariable logistic regression analyses were performed to determine the association between the exercise-related parameters and odds of a glaucoma diagnosis. Main outcome measure(s) Glaucoma defined by International Society for Geographical and Epidemiological Ophthalmology criteria. Results Overall, 336 (2.7%) subjects met diagnostic criteria for glaucomatous disease. After adjustment for potential confounding variables, subjects engaged in vigorous exercise 7 days per week had higher odds of having glaucoma compared with those exercising 3 days per week (Odds Ratio [OR] 3.33, 95% confidence interval [CI] 1.16–9.54). High intensity of exercise, as categorized by the guidelines of the American College of Sports Medicine (ACSM), was also associated with greater glaucoma prevalence compared with moderate intensity of exercise (OR 1.55, 95% CI 1.03–2.33). There was no association between other exercise parameters including frequency of moderate exercise, walking, muscle strength exercise, flexibility training, or total minutes of exercise per week, and the prevalence of glaucoma. In sub-analyses stratifying by gender, the association between frequency of vigorous exercise 7 days per week and glaucoma diagnosis remained significant in men (OR 6.05, 95% CI 1.67–21.94) but not in women (OR 0.96 95% CI: 0.23–3.97). A U-shaped association between exercise intensity and glaucoma prevalence was noted in men (OR 1.71, 95% CI 1.09–2.69 for low intensity versus moderate intensity; OR 2.19, 95% CI 1.25–3.85 for high intensity versus moderate intensity). Conclusion In a South Korean population sample, daily vigorous exercise was associated with higher glaucoma prevalence. In addition, the intensity of exercise was positively associated with glaucoma diagnosis in men but not women. PMID:28187143

The effect of physical exercise on salivary secretion of MUC5B, amylase and lysozyme.

PubMed

Ligtenberg, Antoon J M; Brand, Henk S; van den Keijbus, Petra A M; Veerman, Enno C I

2015-11-01

Saliva secretion is regulated by the autonomic nervous system. Parasympathic stimuli increase the secretion of water and mucin MUC5B, whereas sympathetic stimuli such as physical exercise increase the secretion of amylase and other proteins. In the present study we investigated the effect of physical exercise, as a sympathetic stimulus, on salivary flow rate and output of MUC5B, amylase, lysozyme and total protein. Unstimulated whole saliva was collected before exercise (1), after 10 min exercise with moderate intensity by running with a heart rate around 130 beats per minute (2), followed by 10 min exercise with high intensity by running to exhaustion (3) and after 30 min recovery (4). Salivary flow rate, protein and MUC5B concentration, and amylase and lysozyme activity were determined. Saliva protein composition was analysed using SDS-PAGE and immunoblotting. Salivary flow rate, protein and lysozyme secretion increased after exercise with moderate intensity and increased further after exercise with high intensity (p<0.01). Amylase and MUC5B increased after exercise with moderate intensity (p<0.0001), but did not differ significantly between moderate and high exercise intensity. SDS-PAGE analysis and immunoblotting showed that, especially after exercise with high intensity, the concentrations of several other salivary proteins, including MUC7, albumin, and extra-parotid glycoprotein, also increased. Exercise may not only lead to the anticipated increase in amylase and protein secretion, but also to an increase in salivary flow rate and MUC5B secretion. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effects of exercise program on burnout and metabolic syndrome components in banking and insurance workers.

PubMed

Tsai, Han Hui; Yeh, Ching Ying; Su, Chien Tien; Chen, Chiou Jong; Peng, Shu Mei; Chen, Ruey Yu

2013-01-01

To explore the effectiveness of exercise program for banking and insurance workers and clarify the association between exercise, burnout, and metabolic syndrome components. In the process of the study, a practicable worksite exercise program was developed for bank and insurance enterprises. A three-month (12-wk) exercise course was conducted, and its benefits evaluated. Levels of burnout and metabolic syndrome components were analyzed after exercise intervention. After intervention, the indicators of burnout and metabolic syndrome components were significantly improved in both low and high intensity groups, and the improvement were expressed in reduction of waist circumference, systolic blood pressure, person burnout and work-related burnout. A dose-response of burnouts and metabolic syndrome components with exercise intensity are shown (p<0.05). Metabolic syndrome components were independently associated with burnout and exercise intensity in the crude model. After adjustment for potential confounders, waist circumference and systolic blood pressure differences showed significant associations with exercise intensity (p<0.05). This study demonstrated an effective approach to worksite exercise intervention and exercise intensity played an important role to alleviate damage between burnouts and metabolic syndrome components.

Continuous low- to moderate-intensity exercise training is as effective as moderate- to high-intensity exercise training at lowering blood HbA(1c) in obese type 2 diabetes patients.

PubMed

Hansen, D; Dendale, P; Jonkers, R A M; Beelen, M; Manders, R J F; Corluy, L; Mullens, A; Berger, J; Meeusen, R; van Loon, L J C

2009-09-01

Exercise represents an effective interventional strategy to improve glycaemic control in type 2 diabetes patients. However, the impact of exercise intensity on the benefits of exercise training remains to be established. In the present study, we compared the clinical benefits of 6 months of continuous low- to moderate-intensity exercise training with those of continuous moderate- to high-intensity exercise training, matched for energy expenditure, in obese type 2 diabetes patients. Fifty male obese type 2 diabetes patients (age 59 +/- 8 years, BMI 32 +/- 4 kg/m(2)) participated in a 6 month continuous endurance-type exercise training programme. All participants performed three supervised exercise sessions per week, either 55 min at 50% of whole body peak oxygen uptake (VO(2)peak (low to moderate intensity) or 40 min at 75% of VO(2)peak (moderate to high intensity). Oral glucose tolerance, blood glycated haemoglobin, lipid profile, body composition, maximal workload capacity, whole body and skeletal muscle oxidative capacity and skeletal muscle fibre type composition were assessed before and after 2 and 6 months of intervention. The entire 6 month intervention programme was completed by 37 participants. Continuous endurance-type exercise training reduced blood glycated haemoglobin levels, LDL-cholesterol concentrations, body weight and leg fat mass, and increased VO(2)peak, lean muscle mass and skeletal muscle cytochrome c oxidase and citrate synthase activity (p < 0.05). No differences were observed between the groups training at low to moderate or moderate to high intensity. When matched for energy cost, prolonged continuous low- to moderate-intensity endurance-type exercise training is equally effective as continuous moderate- to high-intensity training in lowering blood glycated haemoglobin and increasing whole body and skeletal muscle oxidative capacity in obese type 2 diabetes patients. ISRCTN32206301 None.

Intensity of Leisure-Time Exercise and Risk of Depressive Symptoms Among Japanese Workers: A Cohort Study.

PubMed

Kuwahara, Keisuke; Honda, Toru; Nakagawa, Tohru; Yamamoto, Shuichiro; Hayashi, Takeshi; Mizoue, Tetsuya

2018-02-05

Data on the effect of physical activity intensity on depression is scarce. We investigated the prospective association between intensity of leisure-time exercise and risk of depressive symptoms among Japanese workers. The participants were 29,052 employees (24,653 men and 4,399 women) aged 20 to 64 years without psychiatric disease including depressive symptoms at health checkup in 2006-2007 and were followed up until 2014-2015. Details of leisure-time exercise were ascertained via a questionnaire. Depressive states were assessed using a 13-item questionnaire. Multivariable-adjusted hazard ratio of depressive symptoms was estimated using Cox regression analysis. During a mean follow-up of 5.8 years with 168,203 person-years, 6,847 workers developed depressive symptoms. Compared with workers who engaged in no exercise during leisure-time (0 MET-hours per week), hazard ratios (95% confidence intervals) associated with >0 to <7.5, 7.5 to <15.0, and ≥15.0 MET-hours of leisure-time exercise were 0.88 (0.82-0.94), 0.85 (0.76-0.94), and 0.78 (0.68-0.88) among workers who engaged in moderate-intensity exercise alone; 0.93 (0.82-1.06), 0.82 (0.68-0.98), and 0.83 (0.71-0.98) among workers who engaged in vigorous-intensity exercise alone; and 0.96 (0.80-1.15), 0.80 (0.67-0.95), and 0.76 (0.66-0.87) among workers who engaged in both moderate- and vigorous-intensity exercise with adjustment for age, sex, lifestyles, work-related and socioeconomic factors, and body mass index. Additional adjustment for baseline depression score attenuated the inverse association, especially among those who engaged in moderate-intensity exercise alone. The results suggest that vigorous-intensity exercise alone or vigorous-intensity combined with moderate-intensity exercise would prevent depressive symptoms among Japanese workers.

Plasma Irisin Modestly Increases during Moderate and High-Intensity Afternoon Exercise in Obese Females

PubMed Central

Winn, Nathan C.; Grunewald, Zachary I.; Liu, Ying; Heden, Timothy D.; Nyhoff, Lauren M.; Kanaley, Jill A.

2017-01-01

Background and Purpose Irisin is an exercise-responsive myokine that has been proposed to exert anti-obesity benefits; yet its response during exercise in obese women is not described. This study characterized plasma irisin levels during a single bout of afternoon isocaloric-exercise of different intensities (moderate- vs high-intensity) in obese females. Methods Eleven obese females participated in 3 randomized study days beginning at 1600h: 1) no exercise (NoEx), 2) moderate exercise (ModEx; 55%VO2max) and 3) high intensity interval exercise (IntEx; 4 min (80%VO2max)/3 min (50% VO2max). Frequent blood samples were analyzed for glucose and lactate (whole-blood), and insulin, c-peptide, glucagon, and irisin (plasma) throughout 190 min of testing. Results Plasma irisin increased above baseline during ModEx and IntEx (P<0.05), but not NoEx (P>0.05). Peak irisin levels during ModEx and IntEx exercise were 11.9± 3.4% and 12.3 ± 4.1% relative to baseline (P<0.05), respectively, with no differences between exercise intensities (P>0.05). Irisin levels remained elevated above resting for 125 minutes post-exercise during ModEx, whereas levels returned to baseline within 15 minutes post-exercise during IntEx. Similarly, no associations were found between plasma irisin levels and circulating lactate, glucose, insulin, c-peptide, or glucagon among study days (P>0.05). However, there was an inverse association between basal irisin and lean mass (r = -0.70, P = 0.01). Conclusion A single bout of moderate and high intensity afternoon exercise induces modest increases in circulating irisin concentrations during exercise; however the regulation post-exercise appears to be dimorphic between exercise intensity in obese females. Future studies are needed to compare morning and afternoon exercise on irisin secretion. PMID:28125733

The anaerobic threshold: over-valued or under-utilized? A novel concept to enhance lipid optimization!

PubMed

Connolly, Declan A J

2012-09-01

The purpose of this article is to assess the value of the anaerobic threshold for use in clinical populations with the intent to improve exercise adaptations and outcomes. The anaerobic threshold is generally poorly understood, improperly used, and poorly measured. It is rarely used in clinical settings and often reserved for athletic performance testing. Increased exercise participation within both clinical and other less healthy populations has increased our attention to optimizing exercise outcomes. Of particular interest is the optimization of lipid metabolism during exercise in order to improve numerous conditions such as blood lipid profile, insulin sensitivity and secretion, and weight loss. Numerous authors report on the benefits of appropriate exercise intensity in optimizing outcomes even though regulation of intensity has proved difficult for many. Despite limited use, selected exercise physiology markers have considerable merit in exercise-intensity regulation. The anaerobic threshold, and other markers such as heart rate, may well provide a simple and valuable mechanism for regulating exercising intensity. The use of the anaerobic threshold and accurate target heart rate to regulate exercise intensity is a valuable approach that is under-utilized across populations. The measurement of the anaerobic threshold can be simplified to allow clients to use nonlaboratory measures, for example heart rate, in order to self-regulate exercise intensity and improve outcomes.

Functional ankle control of rock climbers

PubMed Central

Schweizer, A; Bircher, H; Kaelin, X; Ochsner, P

2005-01-01

Objective: To evaluate whether rock climbing type exercise would be of value in rehabilitating ankle injuries to improve ankle stability and coordination. Results: The rock climbers showed significantly better results in the stabilometry and greater absolute and relative maximum strength of flexion in the ankle. The soccer players showed greater absolute but not relative strength in extension. Conclusion: Rock climbing, because of its slow and controlled near static movements, may be of value in the treatment of functional ankle instability. However, it has still to be confirmed whether it is superior to the usual rehabilitation exercises such as use of the wobble board. PMID:15976164

Moderating influence of dominant attentional style and exercise intensity on responses to asynchronous music.

PubMed

Hutchinson, Jasmin C; Karageorghis, Costas I

2013-12-01

We examined independent and combined influences of asynchronous music and dominant attentional style (DAS) on psychological and psychophysical variables during exercise using mixed methods. Participants (N = 34) were grouped according to DAS and completed treadmill runs at three intensities (low, moderate, high) crossed with three music conditions (motivational, oudeterous, no-music control). State attentional focus shifted from dissociative to associative with increasing intensity and was most aligned with DAS during moderate-intensity exercise. Both music conditions facilitated dissociation at low-to-moderate intensities. At high exercise intensity, both music conditions were associated with reduced RPE among participants with an associative DAS. Dissociators reported higher RPE overall during moderate and high intensities. Psychological responses were most positive in the motivational condition, followed by oudeterous and control. Findings illustrate the relevance of individual differences in DAS as well as task intensity and duration when selecting music for exercise.

Self-selected music-induced reduction of perceived exertion during moderate-intensity exercise does not interfere with post-exercise improvements in inhibitory control.

PubMed

Tanaka, Daichi; Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Hamaoka, Takafumi; Hashimoto, Takeshi; Isaka, Tadao

2018-05-26

Acute aerobic exercise improves inhibitory control (IC). This improvement is often associated with increases in perceived exertion during exercise. However, listening to music during aerobic exercise mitigates an exercise-induced increase in perceived exertion. Thus, it is hypothesized that such effects of music may interfere with exercise-induced improvements in IC. To test this hypothesis, we examined the effect of music on post-exercise IC improvements that were induced by moderate-intensity exercise. Fifteen healthy young men performed cycle ergometer exercise with music or non-music. The exercise was performed using a moderate-intensity of 60% of VO 2 peak for 30 min. The music condition was performed while listening to self-selected music. The non-music condition involved no music. To evaluate IC, the Stroop task was administered before exercise, immediately after exercise, and during the 30-min post-exercise recovery period. The rate of perceived exertion immediately before moderate-intensity exercise completed was significantly lower in music condition than in non-music condition. The IC significantly improved immediately after exercise and during the post-exercise recovery period compared to before exercise in both music and non-music conditions. The post-exercise IC improvements did not significantly differ between the two conditions. These findings indicate that self-selected music-induced mitigation of the increase in perceived exertion during moderate-intensity exercise dose not interfere with exercise-induced improvements in IC. Therefore, we suggest that listening to music may be a beneficial strategy in mitigating the increase in perceived exertion during aerobic exercise without decreasing the positive effects on IC. Copyright © 2018 Elsevier Inc. All rights reserved.

Psychophysiological Responses to Group Exercise Training Sessions: Does Exercise Intensity Matter?

PubMed

Vandoni, Matteo; Codrons, Erwan; Marin, Luca; Correale, Luca; Bigliassi, Marcelo; Buzzachera, Cosme Franklim

2016-01-01

Group exercise training programs were introduced as a strategy for improving health and fitness and potentially reducing dropout rates. This study examined the psychophysiological responses to group exercise training sessions. Twenty-seven adults completed two group exercise training sessions of moderate and vigorous exercise intensities in a random and counterbalanced order. The %HRR and the exertional and arousal responses to vigorous session were higher than those during the moderate session (p<0.05). Consequently, the affective responses to vigorous session were less pleasant than those during moderate session (p<0.05). These results suggest that the psychophysiological responses to group exercise training sessions are intensity-dependent. From an adherence perspective, interventionists are encouraged to emphasize group exercise training sessions at a moderate intensity to maximize affective responses and to minimize exertional responses, which in turn may positively affect future exercise behavior.

The Effect of Acute Exercise on Affect and Arousal in Inpatient Mental Health Consumers.

PubMed

Stanton, Robert; Reaburn, Peter; Happell, Brenda

2016-09-01

Acute exercise performed at a self-selected intensity improves affect and may improve long-term adherence. Similarly, in people with severe depression, acute aerobic exercise performed at self-selected intensity improves affect and arousal. However, the relationship between changes in affect and arousal and perceived exercise intensity in people with mental illness has not been evaluated. Affect and arousal were assessed immediately prior to, and immediately following, a group exercise program performed at a self-selected intensity in 40 inpatient mental health consumers who received a diagnosis of anxiety or bipolar or depressive disorders. Exercise intensity was assessed immediately after exercise. Postexercise affect was significantly improved for people with bipolar and depressive disorders but not for people with anxiety disorders. For the group as a whole, results showed a significant curvilinear relationship between ratings of perceived exertion and postexercise affect. These data will inform the development and delivery of future exercise interventions for inpatient mental health consumers.

High-intensity interval training evokes larger serum BDNF levels compared with intense continuous exercise.

PubMed

Saucedo Marquez, Cinthia Maria; Vanaudenaerde, Bart; Troosters, Thierry; Wenderoth, Nicole

2015-12-15

Exercise can have a positive effect on the brain by activating brain-derived neurotrophic factor (BDNF)-related processes. In healthy humans there appears to be a linear relationship between exercise intensity and the positive short-term effect of acute exercise on BDNF levels (i.e., the highest BDNF levels are reported after high-intensity exercise protocols). Here we performed two experiments to test the effectiveness of two high-intensity exercise protocols, both known to improve cardiovascular health, to determine whether they have a similar efficacy in affecting BDNF levels. Participants performed a continuous exercise (CON) protocol at 70% of maximal work rate and a high-intensity interval-training (HIT) protocol at 90% of maximal work rate for periods of 1 min alternating with 1 min of rest (both protocols lasted 20 min). We observed similar BDNF kinetics in both protocols, with maximal BDNF concentrations being reached toward the end of training (experiment 1). We then showed that both exercise protocols significantly increase BDNF levels compared with a rest condition (CON P = 0.04; HIT P < 0.001), with HIT reaching higher BDNF levels than CON (P = 0.035) (experiment 2). These results suggest that shorter bouts of high intensity exercise are slightly more effective than continuous high-intensity exercise for elevating serum BDNF. Additionally, 73% of the participants preferred the HIT protocol (P = 0.02). Therefore, we suggest that the HIT protocol might represent an effective and preferred intervention for elevating BDNF levels and potentially promoting brain health. Copyright © 2015 the American Physiological Society.

Contributions of Astronauts Aerobic Exercise Intensity and Time on Change in VO2peak during Spaceflight

NASA Technical Reports Server (NTRS)

Downs, Meghan E.; Buxton, Roxanne; Moore, Alan; Ploutz-Snyder, Robert; Ploutz-Snyder, Lori

2014-01-01

There is considerable variability among astronauts with respect to changes in maximal aerobic capacity (VO2peak) during International Space Station (ISS) missions, ranging from a 5% increase to 30% decline. Individual differences may be due to in-flight aerobic exercise time and intensity. PURPOSE: To evaluate the effects of in-flight aerobic exercise time and intensity on change in VO2peak during ISS missions. METHODS: Astronauts (N=11) performed peak cycle tests approx 60 days before flight (L-60), on flight day (FD) approx 14, and every approx 30 days thereafter. Metabolic gas analysis and heart rate (HR) were measured continuously during the test using the portable pulmonary function system. HR and duration of each in-flight cycle ergometer and treadmill (TM) session were recorded and averaged in time segments corresponding to each peak test. Mixed effects linear regression with exercise mode (TM or cycle) as a categorical variable was used to assess the contributions of exercise intensity (%time >70% peak HR or %time >90% peak HR) and time (min/wk), adjusted for body weight, on %change in VO2peak during the mission, and incorporating the repeated-measures experimental design. RESULTS: 110 observations were included in the model (4-6 peak cycle tests per astronaut, 2 exercise devices). VO2peak was reduced from preflight throughout the mission (FD14: 13+/-13% and FD 105: 8+/-10%). Exercise intensity (%peak HR: FD14=66+/-14; FD105=75+/-8) and time (min/wk: FD14=82+/-46; FD105=158+/-40) increased during flight. The models showed main effects for exercise time and intensity with no interactions between time, intensity, and device (70% peak HR: time [z-score=2.39; P=0.017], intensity [z-score=3.51; P=0.000]; 90% peak HR: time [zscore= 3.31; P=0.001], intensity [z-score=2.24; P=0.025]). CONCLUSION: Exercise time and intensity independently contribute to %change in VO2peak during ISS missions, indicating that there are minimal values for exercise time and intensity required to maintain VO2peak. As the FD105 average exercise intensity and time did not prevent a decline in VO2peak from preflight, astronauts' exercise prescriptions should target at least 160 min of weekly aerobic exercise at an average above 75% peak HR with increased time at intensities above 90% of peak HR starting early in the mission.

Effect of exercise intensity on circulating microparticles in men and women.

PubMed

Shill, Daniel D; Lansford, Kasey A; Hempel, Hannah K; Call, Jarrod A; Murrow, Jonathan R; Jenkins, Nathan T

2018-05-01

What is the central question of this study? What is the effect of exercise intensity on circulating microparticle populations in young, healthy men and women? What is the main finding and its importance? Acute, moderate-intensity continuous exercise and high-intensity interval exercise altered distinct microparticle populations during and after exercise in addition to a sex-specific response in CD62E + microparticles. The microparticles studied contribute to cardiovascular disease progression, regulate vascular function and facilitate new blood vessel formation. Thus, characterizing the impact of intensity on exercise-induced microparticle responses advances our understanding of potential mechanisms underlying the beneficial vascular adaptations to exercise. Circulating microparticles (MPs) are biological vectors of information within the cardiovascular system that elicit both deleterious and beneficial effects on the vasculature. Acute exercise has been shown to alter MP concentrations, probably through a shear stress-dependent mechanism, but evidence is limited. Therefore, we investigated the effect of exercise intensity on plasma levels of CD34 + and CD62E + MPs in young, healthy men and women. Blood samples were collected before, during and after two energy-matched bouts of acute treadmill exercise: interval exercise (10 × 1 min intervals at ∼95% of maximal oxygen uptake V̇O2max) and continuous exercise (65% V̇O2max). Continuous exercise, but not interval exercise, reduced CD62E + MP concentrations in men and women by 18% immediately after exercise (from 914.5 ± 589.6 to 754.4 ± 390.5 MPs μl -1 ; P < 0.05), suggesting that mechanisms underlying exercise-induced CD62E + MP dynamics are intensity dependent. Furthermore, continuous exercise reduced CD62E + MPs in women by 19% (from 1030.6 ± 688.1 to 829.9 ± 435.4 MPs μl -1 ; P < 0.05), but not in men. Although interval exercise did not alter CD62E + MPs per se, the concentrations after interval exercise were higher than those observed after continuous exercise (P < 0.05). Conversely, CD34 + MPs did not fluctuate in response to short-duration acute continuous or interval exercise in men or women. Our results suggest that exercise-induced MP alterations are intensity dependent and sex specific and impact MP populations differentially. © 2018 The Authors. Experimental Physiology © 2018 The Physiological Society.

Post-plyometric exercise hypotension and heart rate in normotensive individuals: influence of exercise intensity.

PubMed

Arazi, Hamid; Asadi, Abbas; Rahimzadeh, Mehdi; Moradkhani, Amir-Hossein

2013-12-01

The purpose of this study was to compare the effects of high, moderate and low intensity plyometric exercise on the post-exercise systolic and diastolic blood pressure and heart rate responses. Ten healthy normotensive men (age, 21.1±0.9 years; height, 175.8±6 cm; and body mass, 69.1±13.6 kg) volunteered to participate in this study and were evaluated for three non-consecutive days in depth jump exercise from 20-cm box (low intensity [LI]), 40-cm box (moderate intensity [MI]) and 60-cm box (high intensity [HI]) for 5 sets of 20 repetitions. After each exercise session, systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured every 10 min for a period of 90 min. No significant differences were observed among post-exercise SBP, DBP and HR when the protocols (LI, MI and HI) were compared. The LI and HI protocols showed greater reduction in SBP at 40(th)-70(th) min of post-exercise (~9%), whereas the LI and MI protocols indicated greater reduction in DBP at 10(th)-50(th) min of post exercise (~10%). In addition, the change in the DBP for HI was not significant and the increases in the HR were similar for all intensities. It can be concluded that a plyometric exercise (PE) can reduce SBP and DBP post-exercise and therefore we can say that PE has significant effects for reducing BP and HR or post-exercise hypotension.

Effects of recovery mode (active vs. passive) on performance during a short high-intensity interval training program: a longitudinal study.

PubMed

Ben Abderrahman, Abderraouf; Zouhal, Hassane; Chamari, Karim; Thevenet, Delphine; de Mullenheim, Pierre-Yves; Gastinger, Steven; Tabka, Zouhair; Prioux, Jacques

2013-06-01

The aim of this longitudinal study was to compare two recovery modes (active vs. passive) during a seven-week high-intensity interval training program (SWHITP) aimed to improve maximal oxygen uptake ([Formula: see text]), maximal aerobic velocity (MAV), time to exhaustion (t lim) and time spent at a high percentage of [Formula: see text], i.e., above 90 % (t90 [Formula: see text]) and 95 % (t95 [Formula: see text]) of [Formula: see text]. Twenty-four adults were randomly assigned to a control group that did not train (CG, n = 6) and two training groups: intermittent exercise (30 s exercise/30 s recovery) with active (IEA, n = 9) or passive recovery (IEP, n = 9). Before and after seven weeks with (IEA and IEP) or without (CG) high-intensity interval training (HIT) program, all subjects performed a maximal graded test to determine their [Formula: see text] and MAV. Subsequently only the subjects of IEA and IEP groups carried out an intermittent exercise test consisting of repeating as long as possible 30 s intensive runs at 105 % of MAV alternating with 30 s active recovery at 50 % of MAV (IEA) or 30 s passive recovery (IEP). Within IEA and IEP, mean t lim and MAV significantly increased between the onset and the end of the SWHITP and no significant difference was found in t90 VO2max and t95 VO2max. Furthermore, before and after the SWHITP, passive recovery allowed a longer t lim for a similar time spent at a high percentage of VO2max. Finally, within IEA, but not in IEP, mean VO2max increased significantly between the onset and the end of the SWHITP both in absolute (p < 0.01) and relative values (p < 0.05). In conclusion, our results showed a significant increase in VO2max after a SWHITP with active recovery in spite of the fact that t lim was significantly longer (more than twice longer) with respect to passive recovery.

Exercise intensity modulates the change in cerebral blood flow following aerobic exercise in chronic stroke.

PubMed

Robertson, Andrew D; Crane, David E; Rajab, A Saeed; Swardfager, Walter; Marzolini, Susan; Shirzadi, Zahra; Middleton, Laura E; MacIntosh, Bradley J

2015-08-01

The mechanisms supporting functional improvement by aerobic exercise following stroke remain incompletely understood. This study investigated how cycling intensity and aerobic fitness influence cerebral blood flow (CBF) following a single exercise session. Thirteen community-living stroke survivors performed 20 min of semi-recumbent cycling at low and moderate intensities (40-50 and 60-70 % of heart rate reserve, respectively) as determined from an exercise stress test. CBF was quantified by arterial spin labeling MRI at baseline, as well as 30 and 50 min post-exercise. An intensity-dependent effect was observed in the right post-central and supramarginal gyri up to 50 min after exercise (uncorrected p < 0.005, cluster size ≥10). Regional CBF was increased 18 ± 17 % and reduced 8 ± 12 % following moderate- and low-intensity cycling, respectively. In contrast, CBF changes were similar between sessions in the right lentiform nucleus and mid-frontal gyrus, as well as the left temporal and parietal gyri. Aerobic fitness was directly related to posterior cingulate and thalamic CBF, and inversely related to precuneal CBF at rest (R (2) ≥ 0.75); however, no relationship between fitness and the post-exercise change in CBF was observed. Divergent changes in regional CBF were observed in the right parietal cortex following low- and moderate-intensity exercise, which suggests that intensity of prescribed exercise may be useful in optimizing rehabilitation.

Comparative evaluation of heart rate-based monitors: Apple Watch vs Fitbit Charge HR.

PubMed

Bai, Yang; Hibbing, Paul; Mantis, Constantine; Welk, Gregory J

2018-08-01

The purpose of this investigation was to examine the validity of energy expenditure (EE), steps, and heart rate measured with the Apple Watch 1 and Fitbit Charge HR. Thirty-nine healthy adults wore the two monitors while completing a semi-structured activity protocol consisting of 20 minutes of sedentary activity, 25 minutes of aerobic exercise, and 25 minutes of light intensity physical activity. Criterion measures were obtained from an Oxycon Mobile for EE, a pedometer for steps, and a Polar heart rate strap worn on the chest for heart rate. For estimating whole-trial EE, the mean absolute percent error (MAPE) from Fitbit Charge HR (32.9%) was more than twice that of Apple Watch 1 (15.2%). This trend was consistent for the individual conditions. Both monitors accurately assessed steps during aerobic activity (MAPE Apple : 6.2%; MAPE Fitbit : 9.4%) but overestimated steps in light physical activity. For heart rate, Fitbit Charge HR produced its smallest MAPE in sedentary behaviors (7.2%), followed by aerobic exercise (8.4%), and light activity (10.1%). The Apple Watch 1 had stronger validity than the Fitbit Charge HR for assessing overall EE and steps during aerobic exercise. The Fitbit Charge HR provided heart rate estimates that were statistically equivalent to Polar monitor.

Guidelines for Physical Activity during Pregnancy: Comparisons From Around the World

PubMed Central

Evenson, Kelly R.; Barakat, Ruben; Brown, Wendy J.; Dargent-Molina, Patricia; Haruna, Megumi; Mikkelsen, Ellen M.; Mottola, Michelle F.; Owe, Katrine M.; Rousham, Emily K.; Yeo, SeonAe

2013-01-01

Introduction Women attain numerous benefits from physical activity during pregnancy. However, due to physical changes that occur during pregnancy, special precautions are also needed. This review summarizes current guidelines for physical activity among pregnant women worldwide. Methods We searched PubMed (MedLINE) for country-specific governmental and clinical guidelines on physical activity during pregnancy through the year 2012. We cross-referenced with articles referring to guidelines, with only the most recent included. An abstraction form was used to extract key details and summarize. Results In total, 11 guidelines were identified from nine countries (Australia, Canada, Denmark, France, Japan, Norway, Spain, United Kingdom, United States). Most guidelines supported moderate intensity physical activity during pregnancy (10/11) and indicated specific frequency (9/11) and duration/time (9/11) recommendations. Most guidelines provided advice on initiating an exercise program during pregnancy (10/11). Six guidelines included absolute and relative contraindications to exercise. All guidelines generally ruled-out sports with risks of falls, trauma, or collisions. Six guidelines included indications for stopping exercise during pregnancy. Conclusion This review contrasted pregnancy-related physical activity guidelines from around the world, and can help to inform new guidelines as they are created or updated, and facilitate the development of a worldwide guideline. PMID:25346651

Interleukin-6 and associated cytokine responses to an acute bout of high-intensity interval exercise: the effect of exercise intensity and volume.

PubMed

Cullen, Tom; Thomas, Andrew W; Webb, Richard; Hughes, Michael G

2016-08-01

Acute increases in interleukin (IL)-6 following prolonged exercise are associated with the induction of a transient anti-inflammatory state (e.g., increases in IL-10) that is partly responsible for the health benefits of regular exercise. The purposes of this study were to investigate the IL-6-related inflammatory response to high-intensity interval exercise (HIIE) and to determine the impact of exercise intensity and volume on this response. Ten participants (5 males and 5 females) completed 3 exercise bouts of contrasting intensity and volume (LOW, MOD, and HIGH). The HIGH protocol was based upon standard HIIE protocols, while the MOD and LOW protocols were designed to enable a comparison of exercise intensity and volume with a fixed duration. Inflammatory cytokine concentrations were measured in plasma (IL-6, IL-10) and also determined the level of gene expression (IL-6, IL-10, and IL-4R) in peripheral blood. The plasma IL-6 response to exercise (reported as fold changes) was significantly greater in HIGH (2.70 ± 1.51) than LOW (1.40 ± 0.32) (P = 0.04) and was also positively correlated to the mean exercise oxygen uptake (r = 0.54, P < 0.01). However, there was no change in anti-inflammatory IL-10 or IL-4R responses in plasma or at the level of gene expression. HIIE caused a significant increase in IL-6 and was greater than that seen in low-intensity exercise of the same duration. The increases in IL-6 were relatively small in magnitude, and appear to have been insufficient to induce the acute systemic anti-inflammatory effects, which are evident following longer duration exercise.

How should COPD patients exercise during respiratory rehabilitation? Comparison of exercise modalities and intensities to treat skeletal muscle dysfunction

PubMed Central

Puhan, M; Schunemann, H; Frey, M; Scharplatz, M; Bachmann, L

2005-01-01

Background: Physical exercise is an important component of respiratory rehabilitation because it reverses skeletal muscle dysfunction, a clinically important manifestation of COPD associated with reduced health-related quality of life (HRQL) and survival. However, there is controversy regarding the components of the optimal exercise protocol. A study was undertaken to systematically evaluate and summarise randomised controlled trials (RCTs) comparing different exercise protocols for COPD patients. Methods: Six electronic databases, congress proceedings and bibliographies of included studies were searched without imposing language restrictions. Two reviewers independently screened all records and extracted data on study samples, interventions and methodological characteristics of included studies. Results: The methodological quality of the 15 included RCTs was low to moderate. Strength exercise led to larger improvements of HRQL than endurance exercise (weighted mean difference for Chronic Respiratory Questionnaire 0.27, 95% CI 0.02 to 0.52). Interval exercise seems to be of similar effectiveness as continuous exercise, but there are few data on clinically relevant outcomes. One small RCT which included patients with mild COPD compared the effect of high and low intensity exercise (at 80% and 40% of the maximum exercise capacity, respectively) and found larger physiological training effects from high intensity exercise. Conclusions: Strength exercise should be routinely incorporated in respiratory rehabilitation. There is insufficient evidence to recommend high intensity exercise for COPD patients and investigators should conduct larger high quality trials to evaluate exercise intensities in patients with moderate to severe COPD. PMID:15860711

Evidence based exercise - clinical benefits of high intensity interval training.

PubMed

Shiraev, Tim; Barclay, Gabriella

2012-12-01

Aerobic exercise has a marked impact on cardiovascular disease risk. Benefits include improved serum lipid profiles, blood pressure and inflammatory markers as well as reduced risk of stroke, acute coronary syndrome and overall cardiovascular mortality. Most exercise programs prescribed for fat reduction involve continuous, moderate aerobic exercise, as per Australian Heart Foundation clinical guidelines. This article describes the benefits of exercise for patients with cardiovascular and metabolic disease and details the numerous benefits of high intensity interval training (HIIT) in particular. Aerobic exercise has numerous benefits for high-risk populations and such benefits, especially weight loss, are amplified with HIIT. High intensity interval training involves repeatedly exercising at a high intensity for 30 seconds to several minutes, separated by 1-5 minutes of recovery (either no or low intensity exercise). HIT is associated with increased patient compliance and improved cardiovascular and metabolic outcomes and is suitable for implementation in both healthy and 'at risk' populations. Importantly, as some types of exercise are contraindicated in certain patient populations and HIIT is a complex concept for those unfamiliar to exercise, some patients may require specific assessment or instruction before commencing a HIIT program.

Effect of High-Intensity Treadmill Exercise on Motor Symptoms in Patients With De Novo Parkinson Disease: A Phase 2 Randomized Clinical Trial.

PubMed

Schenkman, Margaret; Moore, Charity G; Kohrt, Wendy M; Hall, Deborah A; Delitto, Anthony; Comella, Cynthia L; Josbeno, Deborah A; Christiansen, Cory L; Berman, Brian D; Kluger, Benzi M; Melanson, Edward L; Jain, Samay; Robichaud, Julie A; Poon, Cynthia; Corcos, Daniel M

2018-02-01

Parkinson disease is a progressive neurologic disorder. Limited evidence suggests endurance exercise modifies disease severity, particularly high-intensity exercise. To examine the feasibility and safety of high-intensity treadmill exercise in patients with de novo Parkinson disease who are not taking medication and whether the effect on motor symptoms warrants a phase 3 trial. The Study in Parkinson Disease of Exercise (SPARX) was a phase 2, multicenter randomized clinical trial with 3 groups and masked assessors. Individuals from outpatient and community-based clinics were enrolled from May 1, 2012, through November 30, 2015, with the primary end point at 6 months. Individuals with idiopathic Parkinson disease (Hoehn and Yahr stages 1 or 2) aged 40 to 80 years within 5 years of diagnosis who were not exercising at moderate intensity greater than 3 times per week and not expected to need dopaminergic medication within 6 months participated in this study. A total of 384 volunteers were screened by telephone; 128 were randomly assigned to 1 of 3 groups (high-intensity exercise, moderate-intensity exercise, or control). High-intensity treadmill exercise (4 days per week, 80%-85% maximum heart rate [n = 43]), moderate-intensity treadmill exercise (4 days per week, 60%-65% maximum heart rate [n = 45]), or wait-list control (n = 40) for 6 months. Feasibility measures were adherence to prescribed heart rate and exercise frequency of 3 days per week and safety. The clinical outcome was 6-month change in Unified Parkinson's Disease Rating Scale motor score. A total of 128 patients were included in the study (mean [SD] age, 64 [9] years; age range, 40-80 years; 73 [57.0%] male; and 108 [84.4%] non-Hispanic white). Exercise rates were 2.8 (95% CI, 2.4-3.2) days per week at 80.2% (95% CI, 78.8%-81.7%) maximum heart rate in the high-intensity group and 3.2 (95% CI, 2.8-3.6; P = .13) days per week at 65.9% (95% CI, 64.2%-67.7%) maximum heart rate in the moderate-intensity group (P < .001). The mean change in Unified Parkinson's Disease Rating Scale motor score in the high-intensity group was 0.3 (95% CI, -1.7 to 2.3) compared with 3.2 (95% CI, 1.4 to 5.1) in the usual care group (P = .03). The high-intensity group, but not the moderate-intensity group, reached the predefined nonfutility threshold compared with the control group. Anticipated adverse musculoskeletal events were not severe. High-intensity treadmill exercise may be feasible and prescribed safely for patients with Parkinson disease. An efficacy trial is warranted to determine whether high-intensity treadmill exercise produces meaningful clinical benefits in de novo Parkinson disease. clinicaltrials.gov Identifier: NCT01506479.

Effects of exercise intensity on spatial memory performance and hippocampal synaptic plasticity in transient brain ischemic rats.

PubMed

Shih, Pei-Cheng; Yang, Yea-Ru; Wang, Ray-Yau

2013-01-01

Memory impairment is commonly noted in stroke survivors, and can lead to delay of functional recovery. Exercise has been proved to improve memory in adult healthy subjects. Such beneficial effects are often suggested to relate to hippocampal synaptic plasticity, which is important for memory processing. Previous evidence showed that in normal rats, low intensity exercise can improve synaptic plasticity better than high intensity exercise. However, the effects of exercise intensities on hippocampal synaptic plasticity and spatial memory after brain ischemia remain unclear. In this study, we investigated such effects in brain ischemic rats. The middle cerebral artery occlusion (MCAO) procedure was used to induce brain ischemia. After the MCAO procedure, rats were randomly assigned to sedentary (Sed), low-intensity exercise (Low-Ex), or high-intensity exercise (High-Ex) group. Treadmill training began from the second day post MCAO procedure, 30 min/day for 14 consecutive days for the exercise groups. The Low-Ex group was trained at the speed of 8 m/min, while the High-Ex group at the speed of 20 m/min. The spatial memory, hippocampal brain-derived neurotrophic factor (BDNF), synapsin-I, postsynaptic density protein 95 (PSD-95), and dendritic structures were examined to document the effects. Serum corticosterone level was also quantified as stress marker. Our results showed the Low-Ex group, but not the High-Ex group, demonstrated better spatial memory performance than the Sed group. Dendritic complexity and the levels of BDNF and PSD-95 increased significantly only in the Low-Ex group as compared with the Sed group in bilateral hippocampus. Notably, increased level of corticosterone was found in the High-Ex group, implicating higher stress response. In conclusion, after brain ischemia, low intensity exercise may result in better synaptic plasticity and spatial memory performance than high intensity exercise; therefore, the intensity is suggested to be considered during exercise training.

Maternal Exercise during Pregnancy Increases BDNF Levels and Cell Numbers in the Hippocampal Formation but Not in the Cerebral Cortex of Adult Rat Offspring

ERIC Educational Resources Information Center

Gomes da Silva, Sérgio; de Almeida, Alexandre Aparecido; Fernandes, Jansen; Lopim, Glauber Menezes; Cabral, Francisco Romero; Scerni, Débora Amado; de Oliveira-Pinto, Ana Virgínia; Lent, Roberto; Arida, Ricardo Mario

2016-01-01

Clinical evidence has shown that physical exercise during pregnancy may alter brain development and improve cognitive function of offspring. However, the mechanisms through which maternal exercise might promote such effects are not well understood. The present study examined levels of brain-derived neurotrophic factor (BDNF) and absolute cell…

Effect of local cooling on short-term, intense exercise.

PubMed

Kwon, Young S; Robergs, Robert A; Schneider, Suzanne M

2013-07-01

The widespread belief that local cooling impairs short-term, strenuous exercise performance is controversial. Eighteen original investigations involving cooling before and intermittent cooling during short-term, intensive exercise are summarized in this review. Previous literature examining short-term intensive exercise and local cooling primarily has been limited to the effects on muscle performance immediately or within minutes following cold application. Most previous cooling studies used equal and longer than 10 minutes of pre-cooling, and found that cooling reduced strength, performance and endurance. Because short duration, high intensity exercise requires adequate warm-up to prepare for optimal performance, prolonged pre-cooling is not an effective method to prepare for this type of exercise. The literature related to the effect of acute local cooling immediately before short duration, high intensity isotonic exercise such as weight lifting is limited. However, local intermittent cooling during short-term, high intense exercise may provide possible beneficial effects; first, by pain reduction, caused by an "irritation effect" from hand thermal receptors which block pain sensation, or second, by a cooling effect, whereby stimulation of hand thermal receptors or a slight lowering of blood temperature might alter central fatigue.

Effects of Exercise on Physiological and Psychological Variables in Cancer Survivors.

ERIC Educational Resources Information Center

Burnham, Timothy; Wilcox, Anthony

2002-01-01

Investigated the effect of aerobic exercise on physiological and psychological function in people rehabilitating from cancer treatment. Data on people participating in control, moderate-intensity exercise, and low-intensity exercise groups indicated that both exercise programs were equally effective in improving physiological function,…

Can high-intensity exercise be more pleasant?: attentional dissociation using music and video.

PubMed

Jones, Leighton; Karageorghis, Costas I; Ekkekakis, Panteleimon

2014-10-01

Theories suggest that external stimuli (e.g., auditory and visual) may be rendered ineffective in modulating attention when exercise intensity is high. We examined the effects of music and parkland video footage on psychological measures during and after stationary cycling at two intensities: 10% of maximal capacity below ventilatory threshold and 5% above. Participants (N = 34) were exposed to four conditions at each intensity: music only, video only, music and video, and control. Analyses revealed main effects of condition and exercise intensity for affective valence and perceived activation (p < .001), state attention (p < .05), and exercise enjoyment (p < .001). The music-only and music-and-video conditions led to the highest valence and enjoyment scores during and after exercise regardless of intensity. Findings indicate that attentional manipulations can exert a salient influence on affect and enjoyment even at intensities slightly above ventilatory threshold.

Effect of Exercise Intensity and Duration on Postexercise Executive Function.

PubMed

Tsukamoto, Hayato; Takenaka, Saki; Suga, Tadashi; Tanaka, Daichi; Takeuchi, Tatsuya; Hamaoka, Takafumi; Isaka, Tadao; Hashimoto, Takeshi

2017-04-01

The effect of exercise volume represented by exercise intensity and duration on postexercise executive function (EF) improvement remains unclear. In the present study, involving two volume-controlled evaluations, we aimed to compare acute exercise protocols with differing intensities and durations to establish an effective exercise protocol for improving EF. In study 1, 12 healthy male subjects performed cycle ergometer exercise, based on a low-intensity (LI) protocol for 20 min (LI20), moderate-intensity (MI) protocol for 20 min (MI20), and MI20 volume-matched LI protocol for 40 min (LI40). The exercise intensities for the LI and MI were set at 30% and 60% of peak oxygen consumption, respectively. In study 2, 15 healthy male subjects performed MI exercise for 10 min (MI10), MI20, and 40 min (MI40). To evaluate the EF, the color-word Stroop task was administrated before exercise, immediately after exercise, and during the 30-min postexercise recovery. In study 1, postexercise EF improvement was sustained for a longer duration after MI20 than after LI40 and was sustained for a longer duration after LI40 than after LI20. In study 2, although there was no significant difference in post-MI exercise EF improvement, the magnitude of difference in the EF between preexercise and 30-min postexercise recovery period was moderately larger in MI40, but not in MI10 and MI20, indicating that the EF improvement during postexercise recovery could be sustained after MI40. The present findings showed that postexercise EF improvement could be prolonged after MI exercise with a moderate duration compared with volume-matched LI exercise with a longer duration. In addition, MI exercise with a relatively long duration may slightly prolong the postexercise EF improvement.

Effects of High Intensity Interval Training on Increasing Explosive Power, Speed, and Agility

NASA Astrophysics Data System (ADS)

Fajrin, F.; Kusnanik, N. W.; Wijono

2018-01-01

High Intensity Interval Training (HIIT) is a type of exercise that combines high-intensity exercise and low intensity exercise in a certain time interval. This type of training is very effective and efficient to improve the physical components. The process of improving athletes achievement related to how the process of improving the physical components, so the selection of a good practice method will be very helpful. This study aims to analyze how is the effects of HIIT on increasing explosive power, speed, and agility. This type of research is quantitative with quasi-experimental methods. The design of this study used the Matching-Only Design, with data analysis using the t-test (paired sample t-test). After being given the treatment for six weeks, the results showed there are significant increasing in explosive power, speed, and agility. HIIT in this study used a form of exercise plyometric as high-intensity exercise and jogging as mild or moderate intensity exercise. Increase was due to the improvement of neuromuscular characteristics that affect the increase in muscle strength and performance. From the data analysis, researchers concluded that, Exercises of High Intensity Interval Training significantly effect on the increase in Power Limbs, speed, and agility.

Randomized controlled trial evaluating the temporal effects of high-intensity exercise on learning, short-term and long-term memory, and prospective memory.

PubMed

Frith, Emily; Sng, Eveleen; Loprinzi, Paul D

2017-11-01

The broader purpose of this study was to examine the temporal effects of high-intensity exercise on learning, short-term and long-term retrospective memory and prospective memory. Among a sample of 88 young adult participants, 22 were randomized into one of four different groups: exercise before learning, control group, exercise during learning, and exercise after learning. The retrospective assessments (learning, short-term and long-term memory) were assessed using the Rey Auditory Verbal Learning Test. Long-term memory including a 20-min and 24-hr follow-up assessment. Prospective memory was assessed using a time-based procedure by having participants contact (via phone) the researchers at a follow-up time period. The exercise stimulus included a 15-min bout of progressive maximal exertion treadmill exercise. High-intensity exercise prior to memory encoding (vs. exercise during memory encoding or consolidation) was effective in enhancing long-term memory (for both 20-min and 24-h follow-up assessments). We did not observe a differential temporal effect of high-intensity exercise on short-term memory (immediate post-memory encoding), learning or prospective memory. The timing of high-intensity exercise may play an important role in facilitating long-term memory. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Muscle and intensity based hamstring exercise classification in elite female track and field athletes: implications for exercise selection during rehabilitation.

PubMed

Tsaklis, Panagiotis; Malliaropoulos, Nikos; Mendiguchia, Jurdan; Korakakis, Vasileios; Tsapralis, Kyriakos; Pyne, Debasish; Malliaras, Peter

2015-01-01

Hamstring injuries are common in many sports, including track and field. Strains occur in different parts of the hamstring muscle but very little is known about whether common hamstring loading exercises specifically load different hamstring components. The purpose of this study was to investigate muscle activation of different components of the hamstring muscle during common hamstring loading exercises. Twenty elite female track and field athletes were recruited into this study, which had a single-sample, repeated-measures design. Each athlete performed ten hamstring loading exercises, and an electromyogram (EMG) was recorded from the biceps femoris and semitendinosus components of the hamstring. Hamstring EMG during maximal voluntary isometric contraction (MVIC) was used to normalize the mean data across ten repetitions of each exercise. An electrogoniometer synchronized to the EMG was used to determine whether peak EMG activity occurred during muscle-tendon unit lengthening, shortening, or no change in length. Mean EMG values were compared between the two recording sites for each exercise using the Student's t-test. The lunge, dead lift, and kettle swings were low intensity (<50% MVIC) and all showed higher EMG activity for semitendinosus than for biceps femoris. Bridge was low but approaching medium intensity, and the TRX, hamstring bridge, and hamstring curl were all medium intensity exercises (≥50% or <80% MVIC). The Nordic, fitball, and slide leg exercises were all high intensity exercises. Only the fitball exercise showed higher EMG activity in the biceps femoris compared with the semitendinosus. Only lunge and kettle swings showed peak EMG in the muscle-tendon unit lengthening phase and both these exercises involved faster speed. Some exercises selectively activated the lateral and medial distal hamstrings. Low, medium, and high intensity exercises were demonstrated. This information enables the clinician, strength and conditioning coach and physiotherapist to better understand intensity- and muscle-specific activation during hamstring muscle rehabilitation. Therefore, these results may help in designing progressive strengthening and rehabilitation and prevention programs.

Usefulness of a Perceived Exertion Scale for Monitoring Exercise Intensity in Adults with Intellectual Disabilities

ERIC Educational Resources Information Center

Stanish, Heidi I.; Aucoin, Michael

2007-01-01

In order to gain physical fitness and health, exercise must be performed at a sufficient level of intensity. Exercise intensity can be monitored with rated perceived exertion (RPE) scales to promote safe and effective programming. The usefulness of the Children's OMNI Scale as a subjective measure of intensity for adults with intellectual…

Intense Exercise Promotes Adult Hippocampal Neurogenesis But Not Spatial Discrimination

PubMed Central

So, Ji H.; Huang, Chao; Ge, Minyan; Cai, Guangyao; Zhang, Lanqiu; Lu, Yisheng; Mu, Yangling

2017-01-01

Hippocampal neurogenesis persists throughout adult life and plays an important role in learning and memory. Although the influence of physical exercise on neurogenesis has been intensively studied, there is controversy in regard to how the impact of exercise may vary with its regime. Less is known about how distinct exercise paradigms may differentially affect the learning behavior. Here we found that, chronic moderate treadmill running led to an increase of cell proliferation, survival, neuronal differentiation, and migration. In contrast, intense running only promoted neuronal differentiation and migration, which was accompanied with lower expressions of vascular endothelial growth factor, brain-derived neurotrophic factor, insulin-like growth factor 1, and erythropoietin. In addition, the intensely but not mildly exercised animals exhibited a lower mitochondrial activity in the dentate gyrus. Correspondingly, neurogenesis induced by moderate but not intense exercise was sufficient to improve the animal’s ability in spatial pattern separation. Our data indicate that the effect of exercise on spatial learning is intensity-dependent and may involve mechanisms other than a simple increase in the number of new neurons. PMID:28197080

W' expenditure and reconstitution during severe intensity constant power exercise: mechanistic insight into the determinants of W'.

PubMed

Broxterman, Ryan M; Skiba, Phillip F; Craig, Jesse C; Wilcox, Samuel L; Ade, Carl J; Barstow, Thomas J

2016-10-01

The sustainable duration of severe intensity exercise is well-predicted by critical power (CP) and the curvature constant (W'). The development of the W'BAL model allows for the pattern of W' expenditure and reconstitution to be characterized and this model has been applied to intermittent exercise protocols. The purpose of this investigation was to assess the influence of relaxation phase duration and exercise intensity on W' reconstitution during dynamic constant power severe intensity exercise. Six men (24.6 ± 0.9 years, height: 173.5 ± 1.9 cm, body mass: 78.9 ± 5.6 kg) performed severe intensity dynamic handgrip exercise to task failure using 50% and 20% duty cycles. The W'BAL model was fit to each exercise test and the time constant for W' reconstitution (τW') was determined. The τW' was significantly longer for the 50% duty cycle (1640 ± 262 sec) than the 20% duty cycle (863 ± 84 sec, P = 0.02). Additionally, the relationship between τW' and CP was well described as an exponential decay (r(2) = 0.90, P < 0.0001). In conclusion, the W'BAL model is able to characterize the expenditure and reconstitution of W' across the contraction-relaxation cycles comprising severe intensity constant power handgrip exercise. Moreover, the reconstitution of W' during constant power severe intensity exercise is influenced by the relative exercise intensity, the duration of relaxation between contractions, and CP. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Exercise Prescriptions for Training and Rehabilitation in Patients with Heart and Lung Disease.

PubMed

Palermo, Pietro; Corrà, Ugo

2017-07-01

Rehabilitation in patients with advanced cardiac and pulmonary disease has been shown to increase survival and improve quality of life, among many other benefits. Exercise training is the fundamental ingredient in these rehabilitation programs. However, determining the amount of exercise is not straightforward or uniform. Most rehabilitation and training programs fix the time of exercise and set the exercise intensity to the goals of the rehabilitation program and the exercise-related hurdles of the individual. The exercise training intensity prescription must balance the desired gain in conditioning with safety. Symptom-limited cardiopulmonary exercise testing is the fundamental tool to identify the exercise intensity and define the appropriate training. In addition, cardiopulmonary exercise testing provides an understanding of the systems involved in oxygen transport and utilization, making it possible to identify the factors limiting exercise capacity in individual patients.

Effect of resistance exercise intensity on the expression of PGC-1α isoforms and the anabolic and catabolic signaling mediators, IGF-1 and myostatin, in human skeletal muscle.

PubMed

Schwarz, Neil A; McKinley-Barnard, Sarah K; Spillane, Mike B; Andre, Thomas L; Gann, Joshua J; Willoughby, Darryn S

2016-08-01

The purpose of this study was to investigate the acute messenger (mRNA) expression of the peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) isoforms, insulin-like growth factor-1Ea (IGF-1Ea), and myostatin in response to 2 resistance exercise intensities. In a uniform-balanced, crossover design, 10 participants performed 2 separate testing sessions involving a lower body resistance exercise component consisting of a lower intensity (50% of 1-repetition maximum; 1RM) protocol and a higher intensity (80% of 1RM) protocol of equal volumes. Muscle samples were obtained at before exercise, 45 min, 3 h, 24 h, and 48 h postexercise. Resistance exercise did not alter total PGC-1α mRNA expression; however, distinct responses of each PGC-1α isoform were observed. The response of each isoform was consistent between sessions, suggesting no effect of resistance exercise intensity on the complex transcriptional expression of the PGC-1α gene. IGF-1Ea mRNA expression significantly increased following the higher intensity session compared with pre-exercise and the lower intensity session. Myostatin mRNA expression was significantly reduced compared with pre-exercise values at all time points with no difference between exercise intensity. Further research is needed to determine the effects of the various isoforms of PGC-1α in human skeletal muscle on the translational level as well as their relation to the expression of IGF-1 and myostatin.

Influence of high altitude on cerebral blood flow and fuel utilization during exercise and recovery.

PubMed

Smith, K J; MacLeod, D; Willie, C K; Lewis, N C S; Hoiland, R L; Ikeda, K; Tymko, M M; Donnelly, J; Day, T A; MacLeod, N; Lucas, S J E; Ainslie, P N

2014-12-15

We examined the hypotheses that: (1) during incremental exercise and recovery following 4-6 days at high altitude (HA) global cerebral blood flow (gCBF) increases to preserve cerebral oxygen delivery (CDO2) in excess of that required by an increasing cerebral metabolic rate of oxygen ( CM RO2); (2) the trans-cerebral exchange of oxygen vs. carbohydrates (OCI; carbohydrates = glucose + ½lactate) would be similar during exercise and recovery at HA and sea level (SL). Global CBF, intra-cranial arterial blood velocities, extra-cranial blood flows, and arterial-jugular venous substrate differences were measured during progressive steady-state exercise (20, 40, 60, 80, 100% maximum workload (Wmax)) and through 30 min of recovery. Measurements (n = 8) were made at SL and following partial acclimatization to 5050 m. At HA, absolute Wmax was reduced by ∼50%. During submaximal exercise workloads (20-60% Wmax), despite an elevated absolute gCBF (∼20%, P < 0.05) the relative increases in gCBF were not different at HA and SL. In contrast, gCBF was elevated at HA compared with SL during 80 and 100% Wmax and recovery. Notwithstanding a maintained CDO2 and elevated absolute CM RO2 at HA compared with SL, the relative increase in CM RO2 was similar during 20-80% Wmax but half that of the SL response (i.e. 17 vs. 27%; P < 0.05 vs. SL) at 100% Wmax. The OCI was reduced at HA compared with SL during 20, 40, and 60% Wmax but comparable at 80 and 100% Wmax. At HA, OCI returned almost immediately to baseline values during recovery, whereas at SL it remained below baseline. In conclusion, the elevations in gCBF during exercise and recovery at HA serve to maintain CDO2. Despite adequate CDO2 at HA the brain appears to increase non-oxidative metabolism during exercise and recovery. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Influence of high altitude on cerebral blood flow and fuel utilization during exercise and recovery

PubMed Central

Smith, K J; MacLeod, D; Willie, C K; Lewis, N C S; Hoiland, R L; Ikeda, K; Tymko, M M; Donnelly, J; Day, T A; MacLeod, N; Lucas, S J E; Ainslie, P N

2014-01-01

We examined the hypotheses that: (1) during incremental exercise and recovery following 4–6 days at high altitude (HA) global cerebral blood flow (gCBF) increases to preserve cerebral oxygen delivery () in excess of that required by an increasing cerebral metabolic rate of oxygen (); (2) the trans-cerebral exchange of oxygen vs. carbohydrates (OCI; carbohydrates = glucose + ½lactate) would be similar during exercise and recovery at HA and sea level (SL). Global CBF, intra-cranial arterial blood velocities, extra-cranial blood flows, and arterial–jugular venous substrate differences were measured during progressive steady-state exercise (20, 40, 60, 80, 100% maximum workload (Wmax)) and through 30 min of recovery. Measurements (n = 8) were made at SL and following partial acclimatization to 5050 m. At HA, absolute Wmax was reduced by ∼50%. During submaximal exercise workloads (20–60% Wmax), despite an elevated absolute gCBF (∼20%, P < 0.05) the relative increases in gCBF were not different at HA and SL. In contrast, gCBF was elevated at HA compared with SL during 80 and 100% Wmax and recovery. Notwithstanding a maintained and elevated absolute at HA compared with SL, the relative increase in was similar during 20–80% Wmax but half that of the SL response (i.e. 17 vs. 27%; P < 0.05 vs. SL) at 100% Wmax. The OCI was reduced at HA compared with SL during 20, 40, and 60% Wmax but comparable at 80 and 100% Wmax. At HA, OCI returned almost immediately to baseline values during recovery, whereas at SL it remained below baseline. In conclusion, the elevations in gCBF during exercise and recovery at HA serve to maintain . Despite adequate at HA the brain appears to increase non-oxidative metabolism during exercise and recovery. PMID:25362150

Affect-regulated exercise intensity: does training at an intensity that feels 'good' improve physical health?

PubMed

Parfitt, Gaynor; Alrumh, Amnah; Rowlands, Alex V

2012-11-01

Affect-regulated exercise to feel 'good' can be used to control exercise intensity amongst both active and sedentary individuals and should support exercise adherence. It is not known, however, whether affect-regulated exercise training can lead to physical health gains. The aim of this study was to examine if affect-regulated exercise to feel 'good' leads to improved fitness over the course of an 8-week training programme. A repeated measures design (pretest-posttest) with independent groups (training and control). 20 sedentary females completed a submaximal graded exercise test and were then allocated to either a training group or control group. The training group completed two supervised sessions and one unsupervised session per week for 8 weeks. Exercise intensity was affect-regulated to feel 'good'. Following the 8 weeks of training, both groups completed a second submaximal graded exercise test. Repeated measures analyses of variance indicated a significant increase in the time to reach ventilatory threshold in the training group (318 ± 23.7s) compared to control (248 ± 16.9s). Overall compliance to training was high (>92%). Participants in the training group exercised at intensities that would be classified as being in the lower range of the recommended guidelines (≈ 50% V˙O(2) max) for cardiovascular health. Affect-regulated exercise to feel 'good' can be used in a training programme to regulate exercise intensity. This approach led to a 19% increase in time to reach ventilatory threshold, which is indicative of improved fitness. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Post-Plyometric Exercise Hypotension and Heart Rate in Normotensive Individuals: Influence of Exercise Intensity

PubMed Central

Arazi, Hamid; Asadi, Abbas; Rahimzadeh, Mehdi; Moradkhani, Amir-Hossein

2013-01-01

Purpose The purpose of this study was to compare the effects of high, moderate and low intensity plyometric exercise on the post-exercise systolic and diastolic blood pressure and heart rate responses. Methods Ten healthy normotensive men (age, 21.1±0.9 years; height, 175.8±6 cm; and body mass, 69.1±13.6 kg) volunteered to participate in this study and were evaluated for three non-consecutive days in depth jump exercise from 20-cm box (low intensity [LI]), 40-cm box (moderate intensity [MI]) and 60-cm box (high intensity [HI]) for 5 sets of 20 repetitions. After each exercise session, systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured every 10 min for a period of 90 min. Results No significant differences were observed among post-exercise SBP, DBP and HR when the protocols (LI, MI and HI) were compared. The LI and HI protocols showed greater reduction in SBP at 40th-70th min of post-exercise (~9%), whereas the LI and MI protocols indicated greater reduction in DBP at 10th-50th min of post exercise (~10%). In addition, the change in the DBP for HI was not significant and the increases in the HR were similar for all intensities. Conclusion It can be concluded that a plyometric exercise (PE) can reduce SBP and DBP post-exercise and therefore we can say that PE has significant effects for reducing BP and HR or post-exercise hypotension. PMID:24799997

Acute psychological benefits of aerobic exercise: a field study into the effects of exercise characteristics.

PubMed

Rendi, Mária; Szabo, Attila; Szabó, Tamás; Velenczei, Attila; Kovács, Arpád

2008-03-01

Eighty volunteers were tested in their natural exercise environment consisting of a fitness centre they regularly attended. Half of the sample exercised on a stationary bicycle, the other half on a treadmill. All participants filled in the Exercise-Induced Feeling Inventory before and after their 20 min of exercise that was performed at self-selected workload. The results revealed that exercise intensity and the other parallel measures like heart rate, perceived exercise intensity and estimates of burned calories were higher in participants who ran in contrast to those who cycled. There were no differences in self-reports of enjoyment of the exercise sessions and in the psychological improvements from pre- to post-exercise between the groups. It is concluded that significant psychological improvements occur even after a 20-min bout of exercise and these changes are independent of the workload or exercise intensity.

Study protocol for the FITR Heart Study: Feasibility, safety, adherence, and efficacy of high intensity interval training in a hospital-initiated rehabilitation program for coronary heart disease.

PubMed

Taylor, Jenna; Keating, Shelley E; Leveritt, Michael D; Holland, David J; Gomersall, Sjaan R; Coombes, Jeff S

2017-12-01

For decades, moderate intensity continuous training (MICT) has been the cornerstone of exercise prescription for cardiac rehabilitation (CR). High intensity interval training (HIIT) is now recognized in CR exercise guidelines as an appropriate and efficient modality for improving cardiorespiratory fitness, a strong predictor of mortality. However, the clinical application of HIIT in a real world CR setting, in terms of feasibility, safety, and long-term adherence, needs further investigation to address ongoing reservations. Furthermore, studies using objective measures of exercise intensity (such as heart rate; HR) have produced variable outcomes. Therefore we propose investigating the use of subjective measures (such as rating of perceived exertion (RPE)) for prescribing exercise intensity. One hundred adults with coronary artery disease (CAD) attending a hospital-initiated CR program will be randomized to 1) HIIT: 4 × 4 min high intensity intervals at 15-18 RPE interspersed with 3-min active recovery periods or 2) MICT: usual care exercise including 40 min continuous exercise at a moderate intensity corresponding to 11-13 RPE. Primary outcome is change in exercise capacity (peak VO 2 ) following 4 weeks of exercise training. Secondary outcome measures are: feasibility, safety, exercise adherence, body composition, vascular function, inflammatory markers, intrahepatic lipid, energy intake, and dietary behavior over 12-months; and visceral adipose tissue (VAT) following 12 weeks of exercise training. This study aims to address the ongoing concerns regarding the practicality and safety of HIIT in CR programs. We anticipate study findings will lead to the development of a standardized protocol to facilitate CR programs to incorporate HIIT as a standard exercise option for appropriate patients.

Creatine kinase response to high-intensity aerobic exercise in adult-onset muscular dystrophy.

PubMed

Andersen, Søren P; Sveen, Marie-Louise; Hansen, Regitze S; Madsen, Karen L; Hansen, Jonas B; Madsen, Mads; Vissing, John

2013-12-01

We investigated the effect of high-intensity exercise on plasma creatine kinase (CK) in patients with muscular dystrophies. Fourteen patients with Becker (BMD), facioscapulohumeral (FSHD), or limb-girdle type 2 (LGMD2) muscular dystrophy, and 8 healthy subjects performed 5 cycling tests: an incremental max test, and tests at 65%, 75%, 85%, and 95% of maximal oxygen uptake (VO2max ). Heart rate and oxygen consumption were measured during the tests, and plasma CK was measured before, immediately after, and 24 hours after exercise. All subjects were able to perform high-intensity exercise at the different levels. In patients with LGMD2 and FSHD, CK normalized 24 hours after exercise compared with the pre-exercise value, whereas those with BMD and healthy controls had elevated CK values 24 hours after exercise. The findings suggest that high-intensity exercise is generally well tolerated in patients with LGMD2 and FSHD, whereas those with BMD may be more prone to exercise-induced damage. Copyright © 2013 Wiley Periodicals, Inc.

Effects of Pilates Exercise on Salivary Secretory Immunoglobulin A Levels in Older Women.

PubMed

Hwang, Yoonyoung; Park, Jonghoon; Lim, Kiwon

2016-07-01

We examined the effects of a Pilates exercise program on the mucosal immune function in older women. The study population comprised 12 older women who were divided into a Pilates group (PG, n = 6) and a control group (CG, n = 6). Saliva samples were obtained from both groups before and after the experimental period for salivary secretory immunoglobulin A level measurement. In addition, acute high-intensity exercises were performed before and after the three-month Pilates exercise program. After three months, salivary flow was significantly higher in the PG than in the CG. After the acute high-intensity exercises were performed following the three-month Pilates exercise program, the salivary flow rate was significantly higher at all time points. The S-IgA secretion rate significantly increased 30 min after acute high-intensity exercise performed following the three-month Pilates exercise program. This study suggests that regular participation in a moderate-intensity Pilates exercise program can increase salivary flow rate and S-IgA secretion in older women.

Low- and high-intensity treadmill exercise attenuates chronic morphine-induced anxiogenesis and memory impairment but not reductions in hippocampal BDNF in female rats.

PubMed

Ghodrati-Jaldbakhan, Shahrbanoo; Ahmadalipour, Ali; Rashidy-Pour, Ali; Vafaei, Abbas Ali; Miladi-Gorji, Hossein; Alizadeh, Maryam

2017-05-15

Previous studies from our laboratory have shown that treadmill exercise alleviates the deficits in cognitive functions and anxiety behaviors induced by chronic exposure to morphine in male rats. In this study, we investigated the effects of low and high intensities of treadmill exercise on spatial memory, anxiety-like behaviors, and biochemical changes in the hippocampus and serum of morphine-treated female rats. The adult virgin female rats were injected with bi-daily doses (10mg/kg, at 12h intervals) of morphine over a period of 10days. Following these injections, the rats were exercised under low or high intensities for 30min per session on five days a week for four weeks. After exercise training, object location memory, anxiety profile, hippocampal BDNF, and serum corticosterone and BDNF were examined. Morphine-treated animals exhibited increased anxiety levels, impaired object location memory, and reduced hippocampal BDNF. Exercise alleviated these impairing effects on anxiety profile and memory but not hippocampal BDNF. The high-intensity exercise even further reduced the hippocampal BDNF. Additionally, both exercise regimens in the morphine group and the high exercise in the saline group reduced serum BDNF. Finally, the high-intensity exercise enhanced corticosterone serum. These findings indicate that the negative cognitive and behavioral effects of chronic exposure to morphine could be relieved by forced exercise in female rats. However, the exercise intensity is an important factor to be considered during exercise training. Finally, the correlation between changes of brain and serum BDNF and cognitive functions following morphine exposure needs further research. Copyright © 2017 Elsevier B.V. All rights reserved.

Exercise training modalities in chronic heart failure: does high intensity aerobic interval training make the difference?

PubMed

Giallauria, Francesco; Smart, Neil Andrew; Cittadini, Antonio; Vigorito, Carlo

2016-10-14

Exercise training (ET) is strongly recommended in patients with chronic heart failure (CHF). Moderate-intensity aerobic continuous ET is the best established training modality in CHF patients. In the last decade, however, high-intensity interval exercise training (HIIT) has aroused considerable interest in cardiac rehabilitation community. Basically, HIIT consists of repeated bouts of high-intensity exercise alternated with recovery periods. In CHF patients, HIIT exerts larger improvements in exercise capacity compared to moderate-continuous ET. These results are intriguing, mostly considering that better functional capacity translates into an improvement of symptoms and quality of life. Notably, HIIT did not reveal major safety issues; although CHF patients should be clinically stable, have had recent exposure to at least regular moderate-intensity exercise, and appropriate supervision and monitoring during and after the exercise session are mandatory. The impact of HIIT on cardiac dimensions and function and on endothelial function remains uncertain. HIIT should not replace other training modalities in heart failure but should rather complement them. Combining and tailoring different ET modalities according to each patient's baseline clinical characteristics (i.e. exercise capacity, personal needs, preferences and goals) seem the most astute approach to exercise prescription.

Perfusion dynamics assessment with Power Doppler ultrasound in skeletal muscle during maximal and submaximal cycling exercise.

PubMed

Heres, H M; Schoots, T; Tchang, B C Y; Rutten, M C M; Kemps, H M C; van de Vosse, F N; Lopata, R G P

2018-06-01

Assessment of limitations in the perfusion dynamics of skeletal muscle may provide insight in the pathophysiology of exercise intolerance in, e.g., heart failure patients. Power doppler ultrasound (PDUS) has been recognized as a sensitive tool for the detection of muscle blood flow. In this volunteer study (N = 30), a method is demonstrated for perfusion measurements in the vastus lateralis muscle, with PDUS, during standardized cycling exercise protocols, and the test-retest reliability has been investigated. Fixation of the ultrasound probe on the upper leg allowed for continuous PDUS measurements. Cycling exercise protocols included a submaximal and an incremental exercise to maximal power. The relative perfused area (RPA) was determined as a measure of perfusion. Absolute and relative reliability of RPA amplitude and kinetic parameters during exercise (onset, slope, maximum value) and recovery (overshoot, decay time constants) were investigated. A RPA increase during exercise followed by a signal recovery was measured in all volunteers. Amplitudes and kinetic parameters during exercise and recovery showed poor to good relative reliability (ICC ranging from 0.2-0.8), and poor to moderate absolute reliability (coefficient of variation (CV) range 18-60%). A method has been demonstrated which allows for continuous (Power Doppler) ultrasonography and assessment of perfusion dynamics in skeletal muscle during exercise. The reliability of the RPA amplitudes and kinetics ranges from poor to good, while the reliability of the RPA increase in submaximal cycling (ICC = 0.8, CV = 18%) is promising for non-invasive clinical assessment of the muscle perfusion response to daily exercise.

Resistance exercise-induced fluid shifts: change in active muscle size and plasma volume

NASA Technical Reports Server (NTRS)

Ploutz-Snyder, L. L.; Convertino, V. A.; Dudley, G. A.

1995-01-01

The purpose of this study was to test the hypothesis that the reduction in plasma volume (PV) induced by resistance exercise reflects fluid loss to the extravascular space and subsequently selective increase in cross-sectional area (CSA) of active but not inactive skeletal muscle. We compared changes in active and inactive muscle CSA and PV after barbell squat exercise. Magnetic resonance imaging (MRI) was used to quantify muscle involvement in exercise and to determine CSA of muscle groups or individual muscles [vasti (VS), adductor (Add), hamstring (Ham), and rectus femoris (RF)]. Muscle involvement in exercise was determined using exercise-induced contrast shift in spin-spin relaxation time (T2)-weighted MR images immediately postexercise. Alterations in muscle size were based on the mean CSA of individual slices. Hematocrit, hemoglobin, and Evans blue dye were used to estimate changes in PV. Muscle CSA and PV data were obtained preexercise and immediately postexercise and 15 and 45 min thereafter. A hierarchy of muscle involvement in exercise was found such that VS > Add > Ham > RF, with the Ham and RF showing essentially no involvement. CSA of the VS and Add muscle groups were increased 10 and 5%, respectively, immediately after exercise in each thigh with no changes in Ham and RF CSA. PV was decreased 22% immediately following exercise. The absolute loss of PV was correlated (r2 = 0.75) with absolute increase in muscle CSA immediately postexercise, supporting the notion that increased muscle size after resistance exercise reflects primarily fluid movement from the vascular space into active but not inactive muscle.

Imagery use and affective responses during exercise: an examination of cerebral hemodynamics using near-infrared spectroscopy.

PubMed

Tempest, Gavin; Parfitt, Gaynor

2013-10-01

Imagery, as a cognitive strategy, can improve affective responses during moderate-intensity exercise. The effects of imagery at higher intensities of exercise have not been examined. Further, the effect of imagery use and activity in the frontal cortex during exercise is unknown. Using a crossover design (imagery and control), activity of the frontal cortex (reflected by changes in cerebral hemodynamics using near-infrared spectroscopy) and affective responses were measured during exercise at intensities 5% above the ventilatory threshold (VT) and the respiratory compensation point (RCP). Results indicated that imagery use influenced activity of the frontal cortex and was associated with a more positive affective response at intensities above VT, but not RCP to exhaustion (p < .05). These findings provide direct neurophysiological evidence of imagery use and activity in the frontal cortex during exercise at intensities above VT that positively impact affective responses.

Nutrition for endurance sports: marathon, triathlon, and road cycling.

PubMed

Jeukendrup, Asker E

2011-01-01

Endurance sports are increasing in popularity and athletes at all levels are looking for ways to optimize their performance by training and nutrition. For endurance exercise lasting 30 min or more, the most likely contributors to fatigue are dehydration and carbohydrate depletion, whereas gastrointestinal problems, hyperthermia, and hyponatraemia can reduce endurance exercise performance and are potentially health threatening, especially in longer events (>4 h). Although high muscle glycogen concentrations at the start may be beneficial for endurance exercise, this does not necessarily have to be achieved by the traditional supercompensation protocol. An individualized nutritional strategy can be developed that aims to deliver carbohydrate to the working muscle at a rate that is dependent on the absolute exercise intensity as well as the duration of the event. Endurance athletes should attempt to minimize dehydration and limit body mass losses through sweating to 2-3% of body mass. Gastrointestinal problems occur frequently, especially in long-distance races. Problems seem to be highly individual and perhaps genetically determined but may also be related to the intake of highly concentrated carbohydrate solutions, hyperosmotic drinks, as well as the intake of fibre, fat, and protein. Hyponatraemia has occasionally been reported, especially among slower competitors with very high intakes of water or other low sodium drinks. Here I provide a comprehensive overview of recent research findings and suggest several new guidelines for the endurance athlete on the basis of this. These guidelines are more detailed and allow a more individualized approach.

Repeated high-intensity exercise in professional rugby union.

PubMed

Austin, Damien; Gabbett, Tim; Jenkins, David

2011-07-01

The aim of the present study was to describe the frequency, duration, and nature of repeated high-intensity exercise in Super 14 rugby union. Time-motion analysis was used during seven competition matches over the 2008 and 2009 Super 14 seasons; five players from each of four positional groups (front row forwards, back row forwards, inside backs, and outside backs) were assessed (20 players in total). A repeated high-intensity exercise bout was considered to involve three or more sprints, and/or tackles and/or scrum/ruck/maul activities within 21 s during the same passage of play. The range of repeated high-intensity exercise bouts for each group in a match was as follows: 11-18 for front row forwards, 11-21 for back row forwards, 13-18 for inside backs, and 2-11 for outside backs. The durations of the most intense repeated high-intensity exercise bouts for each position ranged from 53 s to 165 s and the minimum recovery periods between repeated high-intensity exercise bouts ranged from 25 s for the back row forwards to 64 s for the front row forwards. The present results show that repeated high-intensity exercise bouts vary in duration and activities relative to position but all players in a game will average at least 10 changes in activity in the most demanding bouts and complete at least one tackle and two sprints. The most intense periods of activity are likely to last as long as 120 s and as little as 25 s recovery may separate consecutive repeated high-intensity exercise bouts. The present findings can be used by coaches to prepare their players for the most demanding passages of play likely to be experienced in elite rugby union.

Blood lactate clearance after maximal exercise depends on active recovery intensity.

PubMed

Devlin, J; Paton, B; Poole, L; Sun, W; Ferguson, C; Wilson, J; Kemi, O J

2014-06-01

High-intensity exercise is time-limited by onset of fatigue, marked by accumulation of blood lactate. This is accentuated at maximal, all-out exercise that rapidly accumulates high blood lactate. The optimal active recovery intensity for clearing lactate after such maximal, all-out exercise remains unknown. Thus, we studied the intensity-dependence of lactate clearance during active recovery after maximal exercise. We constructed a standardized maximal, all-out treadmill exercise protocol that predictably lead to voluntary exhaustion and blood lactate concentration>10 mM. Next, subjects ran series of all-out bouts that increased blood lactate concentration to 11.5±0.2 mM, followed by recovery exercises ranging 0% (passive)-100% of the lactate threshold. Repeated measurements showed faster lactate clearance during active versus passive recovery (P<0.01), and that active recovery at 60-100% of lactate threshold was more efficient for lactate clearance than lower intensity recovery (P<0.05). Active recovery at 80% of lactate threshold had the highest rate of and shortest time constant for lactate clearance (P<0.05), whereas the response during the other intensities was graded (100%=60%>40%>passive recovery, P<0.05). Active recovery after maximal all-out exercise clears accumulated blood lactate faster than passive recovery in an intensity-dependent manner, with maximum clearance occurring at active recovery of 80% of lactate threshold.

Effect of exercise intensity on albuminuria in adolescents with Type 1 diabetes mellitus.

PubMed

Kornhauser, C; Malacara, J-M; Macías-Cervantes, M-H; Rivera-Cisneros, A-E

2012-01-01

Exercise may be useful to detect patients with diabetes prone to develop persistent microalbuminuria. We studied the relationship between exercise intensity, measured as maximal oxygen consumption (VO(2)max), and microalbuminuria in patients with Type 1 diabetes mellitus patients. We studied 10 patients, age range 10-18 years, with Type 1 diabetes who were normotensive and normoalbuminuric, with less than 10 years since diagnosis. Patients had normal renal function, without infections or clinical evidence of complications. Metabolic control was intensively adjusted in all patients. They underwent three consecutive physical exercise tests, reaching 100, 80 and 60% of the maximal cardiac frequency response. Eight patients had adequate to regular metabolic control. All patients had lower than predicted VO(2)max values. At 60%, only three patients showed microalbuminuria in excess of 20 μg/min, two of them had inadequate metabolic control. Post-exercise microalbuminuria exceeded normal values in nine, seven and three patients when submitted to 100, 80 and 60% of exercise intensity, respectively. Microalbuminuria increased with exercise intensity. Sex, body composition and VO(2)max were the main factors associated with microalbuminuria. The prognostic significance of albuminuria induced by intense exercise in these subjects with Type 1 diabetes is not yet known. © 2011 The Authors. Diabetic Medicine © 2011 Diabetes UK.

Morning bright light exposure has no influence on self-chosen exercise intensity and mood in overweight individuals - A randomized controlled trial.

PubMed

Knaier, Raphael; Klenk, Christopher; Königstein, Karsten; Hinrichs, Timo; Rossmeissl, Anja; Infanger, Denis; Cajochen, Christian; Schmidt-Trucksäss, Arno

2018-04-01

Overweight is a worldwide increasing public health issue. Physical exercise is a useful countermeasure. Overweight individuals choose rather low exercise intensities, but especially high exercise intensities lead to higher energy expenditure and show beneficial health effects compared to lower exercise intensities. However, especially in the morning higher exercise intensities are likely to be avoided due to higher subjective effort. Bright light exposure has shown to increase maximum performance. The aim of this study was to investigate if bright light exposure can also increase self-chosen exercise intensity. We hypothesized that morning bright light exposure increases self-chosen exercise intensity of subsequent exercise through increased mood and reduced sleepiness in overweight individuals. In this randomized controlled single-blind parallel group design, 26 overweight individuals (11 males, 15 females; age 25 ± 5.7 years; body mass index 28.9 ± 2.1 kg/m 2 ) underwent three measurement appointments. On the first appointment, subjects performed a cardiopulmonary exercise test to measure maximum oxygen uptake (VO2max). Two days later a 30-min exercise session with self-chosen exercise intensity was performed for familiarization. Then subjects were randomly allocated to bright light (~4400 lx) or a control light (~230 lx) condition. Three to seven days later, subjects were exposed to light for 30 min starting at 8:00 am, immediately followed by a 30-min exercise session with persisting light exposure. Multidimensional mood questionnaires were filled out before and after the light exposure and after the exercise session. The primary outcome was the mean power output during the exercise session and the secondary outcome the rating on the three domains (i.e. good-bad; awake-tired; calm-nervous) of the multidimensional mood questionnaire. Mean power output during the exercise session was 92 ± 19 W in bright light and 80 ± 37 W in control light, respectively. In the multivariate analysis adjusted for VO2max, the mean power output during the exercise session was 8.5 W higher (95% confidence interval -12.7, 29.7; p = 0.416) for participants in bright light compared to control light. There were no significant differences between the groups for any of the three domains of the questionnaire at any time point. This is in contrast to longer lasting intervention studies that show positive influences on mood and suggests that bright light therapy requires repetitive sessions to improve mood in overweight individuals. In conclusion bright light exposure does not acutely increase self-chosen exercise intensity or improve mood in a 30-min exercise session starting at 08:30. However, regarding the fact that overweight is a worldwide and rapidly increasing public health issue even small increases in exercise intensity may be relevant. The trend toward superiority of bright light over control light implicates that further studies may be conducted in a larger scale. VO2max: maximum oxygen uptake; 95% CI: 95% confidence interval; SD: standard deviation.

Attentional bias to emotional stimuli is altered during moderate- but not high-intensity exercise.

PubMed

Tian, Qu; Smith, J Carson

2011-12-01

Little is known regarding how attention to emotional stimuli is affected during simultaneously performed exercise. Attentional biases to emotional face stimuli were assessed in 34 college students (17 women) using the dot-probe task during counterbalanced conditions of moderate- (heart rate at 45% peak oxygen consumption) and high-intensity exercise (heart rate at 80% peak oxygen consumption) compared with seated rest. The dot-probe task consisted of 1 emotional face (pleasant or unpleasant) paired with a neutral face for 1,000 ms; 256 trials (128 trials for each valence) were presented during each condition. Each condition lasted approximately 10 min. Participants were instructed to perform each trial of the dot-probe task as quickly and accurately as possible during the exercise and rest conditions. During moderate-intensity exercise, participants exhibited significantly greater attentional bias scores to pleasant compared with unpleasant faces (p < .01), whereas attentional bias scores to emotional faces did not differ at rest or during high-intensity exercise (p > .05). In addition, the attentional bias to unpleasant faces was significantly reduced during moderate-intensity exercise compared with that during rest (p < .05). These results provide behavioral evidence that during exercise at a moderate intensity, there is a shift in attention allocation toward pleasant emotional stimuli and away from unpleasant emotional stimuli. Future work is needed to determine whether acute exercise may be an effective treatment approach to reduce negative bias or enhance positive bias in individuals diagnosed with mood or anxiety disorders, or whether attentional bias during exercise predicts adherence to exercise. (c) 2011 APA, all rights reserved.

Intensive lifestyle changes for reversal of coronary heart disease.

PubMed

Ornish, D; Scherwitz, L W; Billings, J H; Brown, S E; Gould, K L; Merritt, T A; Sparler, S; Armstrong, W T; Ports, T A; Kirkeeide, R L; Hogeboom, C; Brand, R J

1998-12-16

The Lifestyle Heart Trial demonstrated that intensive lifestyle changes may lead to regression of coronary atherosclerosis after 1 year. To determine the feasibility of patients to sustain intensive lifestyle changes for a total of 5 years and the effects of these lifestyle changes (without lipid-lowering drugs) on coronary heart disease. Randomized controlled trial conducted from 1986 to 1992 using a randomized invitational design. Forty-eight patients with moderate to severe coronary heart disease were randomized to an intensive lifestyle change group or to a usual-care control group, and 35 completed the 5-year follow-up quantitative coronary arteriography. Two tertiary care university medical centers. Intensive lifestyle changes (10% fat whole foods vegetarian diet, aerobic exercise, stress management training, smoking cessation, group psychosocial support) for 5 years. Adherence to intensive lifestyle changes, changes in coronary artery percent diameter stenosis, and cardiac events. Experimental group patients (20 [71%] of 28 patients completed 5-year follow-up) made and maintained comprehensive lifestyle changes for 5 years, whereas control group patients (15 [75%] of 20 patients completed 5-year follow-up) made more moderate changes. In the experimental group, the average percent diameter stenosis at baseline decreased 1.75 absolute percentage points after 1 year (a 4.5% relative improvement) and by 3.1 absolute percentage points after 5 years (a 7.9% relative improvement). In contrast, the average percent diameter stenosis in the control group increased by 2.3 percentage points after 1 year (a 5.4% relative worsening) and by 11.8 percentage points after 5 years (a 27.7% relative worsening) (P=.001 between groups. Twenty-five cardiac events occurred in 28 experimental group patients vs 45 events in 20 control group patients during the 5-year follow-up (risk ratio for any event for the control group, 2.47 [95% confidence interval, 1.48-4.20]). More regression of coronary atherosclerosis occurred after 5 years than after 1 year in the experimental group. In contrast, in the control group, coronary atherosclerosis continued to progress and more than twice as many cardiac events occurred.

Effects of exercise at individual anaerobic threshold and maximal fat oxidation intensities on plasma levels of nesfatin-1 and metabolic health biomarkers.

PubMed

Mohebbi, Hamid; Nourshahi, Maryam; Ghasemikaram, Mansour; Safarimosavi, Saleh

2015-03-01

Exercise is recognized as an effective method of weight management and short-term appetite regulation tool. The effect of different exercise intensities on appetite regulation hormones in healthy overweight participants has not been intensively studied. The aim of this study was to examine the influence of exercise at individual anaerobic threshold (IAT) and maximal fat oxidation (Fatmax) intensities on the nesfatin-1 response and metabolic health biomarkers in overweight men. Nine healthy overweight males (age, 23.1 ± 1.1 years) volunteered in this study in a counterbalanced order. Blood samples were obtained before, immediately after, and following the first 45 min of recovery for measuring plasma variables. There was significant decrease in plasma levels of nesfatin-1 and leptin after exercise at the IAT intensity which remained lower than baseline following 45 min of recovery. However, nesfatin-1 and leptin levels did not change significantly in any time courses of Fatmax intensity (P > 0.09). Plasma interleukin-6 (IL-6) concentration increased during exercise in both intensities (P < 0.05), whereas changes in free fatty acids (FFAs) and epinephrine concentrations were significant only at the IAT. In addition, a significant correlation was found among nesfatin-1 levels with insulin (r = 0.39, P < 0.05) and glucose (r = 0.41, P < 0.05) at basal and in response to exercise. These results indicate that IAT has a greater exercise-induced appetite regulation effect compared with Fat(max). Based on these data, the intensity of exercise may have an important role in changes of nesfatin-1, leptin, FFA, and epinephrine concentrations even though this was not the case for IL-6 and insulin resistance.

Effect of exercise intensity and mode on acute appetite control in men and women.

PubMed

Panissa, Valéria Leme Gonçalves; Julio, Ursula Ferreira; Hardt, Felipe; Kurashima, Carolina; Lira, Fábio Santos; Takito, Monica Yuri; Franchini, Emerson

2016-07-07

The aim of this study was to compare the effects of exercise intensity on appetite control: relative energy intake (energy intake minus the energy expenditure of exercise; REI), hunger scores, and appetite-regulating hormones in men and women. Eleven men and 9 women were submitted to 4 experimental sessions: high-intensity intermittent all-out exercise (HIIE-A) for 60 × 8 s interspersed by 12 s of passive recovery; high-intensity intermittent exercise (HIIE) at 100% of maximal load attained in incremental test; steady-state exercise at 60% of maximal load, matched by work done; and a control session. Exercise was performed 1.5 h after a standardized breakfast, and an ad libitum lunch was offered 4 h after breakfast. Blood concentration of insulin, cortisol, acylated ghrelin, peptideYY 3-36 , glucose, and hunger scores were measured when fasting, and at 1.5, 2, 3.25, and 4 h of experiment. REI was lower in all exercises than in the control, without differences between exercises and sex showing no compensation in energy intake because of any exercise; the hunger scores were lower only in the exercises performed at higher intensity (HIIE and HIIE-A) compared with the control. The area under the curve of acylated ghrelin was lower in the HIIE-A when compared with the control. PeptideYY 3-36 was higher in men than women and cortisol higher in women than men independently of the condition. Although high-intensity exercises promoted a little more pronounced effects in the direction of suppressing the appetite, no differences were observed in REI, demonstrating that these modifications were not sufficient to affect energy intake.

Does exercise motivation predict engagement in objectively assessed bouts of moderate-intensity exercise? A self-determination theory perspective.

PubMed

Standage, Martyn; Sebire, Simon J; Loney, Tom

2008-08-01

This study examined the utility of motivation as advanced by self-determination theory (Deci & Ryan, 2000) in predicting objectively assessed bouts of moderate intensity exercise behavior. Participants provided data pertaining to their exercise motivation. One week later, participants wore a combined accelerometer and heart rate monitor (Actiheart; Cambridge Neurotechnology Ltd) and 24-hr energy expenditure was estimated for 7 days. After controlling for gender and a combined marker of BMI and waist circumference, results showed autonomous motivation to positively predict moderate-intensity exercise bouts of >or=10 min, or=20 min, and an accumulation needed to meet public health recommendations for moderate intensity activity (i.e., ACSM/AHA guidelines). The present findings add bouts of objectively assessed exercise behavior to the growing body of literature that documents the adaptive consequences of engaging in exercise for autonomous reasons. Implications for practice and future work are discussed.

Effect of single-session aerobic exercise with varying intensities on lipid peroxidation and muscle-damage markers in sedentary males.

PubMed

Moflehi, Daruosh; Kok, Lian-Yee; Tengku-Kamalden, Tengku-Fadilah; Amri, Saidon

2012-05-23

This study was conducted to evaluate the effect of the different intensity levels of single-session aerobic exercise on serum levels of lipid peroxidation and muscle damage markers in sedentary males. Fifty one sedentary healthy males aged 21.76±1.89 years were randomly divided into four groups, with one control (n=10) and three treatment groups that attended single-session aerobic exercise with low (n=14), moderate (n=14), and high (n=13) intensities. The serum levels of malondialdehyde (MDA) and creatine kinase (CK) were measured. Data analysis revealed a significant effect by the intensity levels of aerobic exercise on MDA (P=0.001) and CK (P=0.003) post-test when the participants in the treatment groups were compared with the control. When the intensity of aerobic exercise was increased, the amount of MDA and CK was also found to be increased. Single-session aerobic exercise can increase the amount of MDA and CK, suggesting that low intensity level of aerobic exercise should be utilized for more adaptation, and to prevent lipid peroxidation and muscle damage in sedentary males.

Cardiovascular and Affective Outcomes of Active Gaming: Using the Nintendo Wii as a Cardiovascular Training Tool

PubMed Central

Naugle, Keith E.; Naugle, Kelly M.; Wikstrom, Erik A.

2014-01-01

Naugle, KE, Naugle, KM, and Wikstrom, EA. Cardiovascular and affective outcomes of active gaming: Using the Nintendo Wii as a cardiovascular training tool. J Strength Cond Res 28(2): 443–451, 2014–Active-video gaming is purported to produce similar cardiovascular responses as aerobic fitness activities. This study compared the emotional and cardiovascular effects of Wii games with those of traditional exercise in college-aged adults with different exercise backgrounds. Specifically, the percentage of heart rate reserve, rate of perceived exertion (RPE), level of enjoyment, and Positive and Negative Affect Schedule scores were compared between subjects who reported exercising frequently at high intensities (high-intensity exerciser group: age = 20.18 years [0.87]; Height = 165.23 cm [9.97]; Mass = 62.37 kg [11.61]), N = 11 and those who exercise more often at lower intensities (low-intensity exercisers group: age = 20.72 years [1.19]; Height = 164.39 cm [8.05]; Mass = 68.04 kg [10.71]), N = 11. The subjects completed six 20-minute exercises sessions: treadmill walking, stationary cycling, and Wii's Tennis, Boxing, Cycling, and Step. The low-intensity exerciser group achieved a greater percentage of heart rate reserve (a) during traditional exercise compared with that during Wii boxing, (b) playing Wii boxing compared with that for Wii tennis, and (c) playing Wii boxing compared with that when the high-intensity exercisers group played any Wii games (p < 0.05). The RPE was greater for boxing and cycling compared with that for tennis and step (p < 0.05). Ratings of enjoyment and the increase in positive emotion were greater for boxing and for tennis compared with those for traditional exercises (p < 0.05). Results suggest that Wii boxing shows the greatest potential as a cardiovascular fitness tool among the Wii games, particularly for individuals who typically exercise at lower intensities. PMID:23660574

The impact of exercise intensity on the release of cardiac biomarkers in marathon runners.

PubMed

Legaz-Arrese, Alejandro; George, Keith; Carranza-García, Luis Enrique; Munguía-Izquierdo, Diego; Moros-García, Teresa; Serrano-Ostáriz, Enrique

2011-12-01

We sought to determine the influence of exercise intensity on the release of cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in amateur marathon runners. Fourteen runners completed three exercise trials of the same duration but at exercise intensities corresponding to: (a) a competitive marathon [mean ± SD: heart rate 159 ± 7 beat min(-1), finish time 202 ± 14 min]; (b) 95% of individual anaerobic threshold [heart rate 144 ± 6 beat min(-1)] and; (c) 85% of individual anaerobic threshold [heart rate 129 ± 5 beat min(-1)]. cTnI and NT-proBNP were assayed from blood samples collected before, 30 min and 3 h post-exercise for each trial. cTnI and NT-proBNP were not different at baseline before each trial. After exercise at 85% of individual anaerobic threshold cTnI was not significantly elevated. Conversely, cTnI was elevated after exercise at 95% of individual anaerobic threshold (0.016 μg L(-1)) and to an even greater extent after exercise at competition intensity (0.054 μg L(-1)). Peak post-exercise values of NT-proBNP were elevated to a similar extent after all exercise trials (P < 0.05). The upper reference limit for cTnI (0.04 μg L(-1)) was exceeded in six subjects at competition intensity. No data for NT-proBNP surpassed its upper reference limit. Peak post-exercise values for cTnI and NT-proBNP were correlated with their respective baseline values. These data suggest exercise intensity influences the release of cTnI, but not NT-proBNP, and that competitive marathon running intensity is required for cTnI to be elevated over its upper reference limit.

Submaximal exercise intensity modulates acute post-exercise heart rate variability.

PubMed

Michael, Scott; Jay, Ollie; Halaki, Mark; Graham, Kenneth; Davis, Glen M

2016-04-01

This study investigated whether short-term heart rate variability (HRV) can be used to differentiate between the immediate recovery periods following three different intensities of preceding exercise. 12 males cycled for 8 min at three intensities: LOW (40-45 %), MOD (75-80 %) and HIGH (90-95 %) of heart rate (HR) reserve. HRV was assessed during exercise and throughout 10-min seated recovery. 1-min HR recovery was reduced following greater exercise intensities when expressed as R-R interval (RRI, ms) (p < 0.001), but not b min(-1) (p = 0.217). During exercise, the natural logarithm of root mean square of successive differences (Ln-RMSSD) was higher during LOW (1.66 ± 0.47 ms) relative to MOD (1.14 ± 0.32 ms) and HIGH (1.30 ± 0.25 ms) (p ≤ 0.037). Similar results were observed for high-frequency spectra (Ln-HF-LOW: 2.9 ± 1.0; MOD: 1.6 ± 0.6; HIGH: 1.6 ± 0.3 ms(2), p < 0.001). By 1-min recovery, higher preceding exercise intensities resulted in lower HRV amongst all three intensities for Ln-RMSSD (LOW: 3.45 ± 0.58; MOD: 2.34 ± 0.81; HIGH: 1.66 ± 0.78 ms, p < 0.001) and Ln-HF (LOW: 6.0 ± 1.0; MOD: 4.3 ± 1.4; HIGH: 2.8 ± 1.4 ms(2), p < 0.001). Similarly, by 1-min recovery 'HR-corrected' HRV (Ln-RMSSD: RRI × 10(3)) was different amongst all three intensities (LOW: 3.64 ± 0.49; MOD: 2.90 ± 0.65; HIGH: 2.40 ± 0.67, p < 0.001). These differences were maintained throughout 10-min recovery (p ≤ 0.027). Preceding exercise intensity has a graded effect on recovery HRV measures reflecting cardiac vagal activity, even after correcting for the underlying HR. The immediate recovery following exercise is a potentially useful period to investigate autonomic activity, as multiple levels of autonomic activity can be clearly differentiated between using HRV. When investigating post-exercise HRV it is critical to account for the relative exercise intensity.

The influence of high intensity exercise and the Val66Met polymorphism on circulating BDNF and locomotor learning.

PubMed

Helm, Erin E; Matt, Kathleen S; Kirschner, Kenneth F; Pohlig, Ryan T; Kohl, Dave; Reisman, Darcy S

2017-10-01

Brain-derived neurotrophic factor (BDNF) has been directly related to exercise-enhanced motor performance in the neurologically injured animal model; however literature concerning the role of BDNF in the enhancement of motor learning in the human population is limited. Previous studies in healthy subjects have examined the relationship between intensity of an acute bout of exercise, increases in peripheral BDNF and motor learning of a simple isometric upper extremity task. The current study examined the role of high intensity exercise on upregulation of peripheral BDNF levels as well as the role of high intensity exercise in mediation of motor learning and retention of a novel locomotor task in neurologically intact adults. In addition, the impact of a single nucleotide polymorphism in the BDNF gene (Val66Met) in moderating the relationship between exercise and motor learning was explored. It was hypothesized that participation in high intensity exercise prior to practicing a novel walking task (split-belt treadmill walking) would elicit increases in peripheral BDNF as well as promote an increased rate and magnitude of within session learning and retention on a second day of exposure to the walking task. Within session learning and retention would be moderated by the presence or absence of Val66Met polymorphism. Fifty-four neurologically intact participants participated in two sessions of split-belt treadmill walking. Step length and limb phase were measured to assess learning of spatial and temporal parameters of walking. Serum BDNF was collected prior to and immediately following either high intensity exercise or 5min of quiet rest. The results demonstrated that high intensity exercise provides limited additional benefit to learning of a novel locomotor pattern in neurologically intact adults, despite increases in circulating BDNF. In addition, presence of a single nucleotide polymorphism on the BDNF gene did not moderate the magnitude of serum BDNF increases with high intensity exercise, nor did it moderate the relationship between high intensity exercise and locomotor learning. Copyright © 2017 Elsevier Inc. All rights reserved.

Absolute intensity measurements of impurity emissions in a shock tunnel and their consequences for laser-induced fluorescence experiments

NASA Technical Reports Server (NTRS)

Palma, P. C.; Houwing, A. F. P.; Sandeman, R. J.

1993-01-01

Absolute intensity measurements of impurity emissions in a shock tunnel nozzle flow are presented. The impurity emission intensities were measured with a photomultiplier and optical multichannel analyzer and calibrated against an intensity standard. The various metallic contaminants were identified and their intensities measured in the spectral regions 290 to 330 nm and 375 to 385 nm. A comparison with calculated fluorescence intensities for predissociated laser-induced fluorescence signals is made. It is found that the emission background is negligible for most fluorescence experiments.

Muscle and intensity based hamstring exercise classification in elite female track and field athletes: implications for exercise selection during rehabilitation

PubMed Central

Tsaklis, Panagiotis; Malliaropoulos, Nikos; Mendiguchia, Jurdan; Korakakis, Vasileios; Tsapralis, Kyriakos; Pyne, Debasish; Malliaras, Peter

2015-01-01

Background Hamstring injuries are common in many sports, including track and field. Strains occur in different parts of the hamstring muscle but very little is known about whether common hamstring loading exercises specifically load different hamstring components. The purpose of this study was to investigate muscle activation of different components of the hamstring muscle during common hamstring loading exercises. Methods Twenty elite female track and field athletes were recruited into this study, which had a single-sample, repeated-measures design. Each athlete performed ten hamstring loading exercises, and an electromyogram (EMG) was recorded from the biceps femoris and semitendinosus components of the hamstring. Hamstring EMG during maximal voluntary isometric contraction (MVIC) was used to normalize the mean data across ten repetitions of each exercise. An electrogoniometer synchronized to the EMG was used to determine whether peak EMG activity occurred during muscle-tendon unit lengthening, shortening, or no change in length. Mean EMG values were compared between the two recording sites for each exercise using the Student’s t-test. Results The lunge, dead lift, and kettle swings were low intensity (<50% MVIC) and all showed higher EMG activity for semitendinosus than for biceps femoris. Bridge was low but approaching medium intensity, and the TRX, hamstring bridge, and hamstring curl were all medium intensity exercises (≥50% or <80% MVIC). The Nordic, fitball, and slide leg exercises were all high intensity exercises. Only the fitball exercise showed higher EMG activity in the biceps femoris compared with the semitendinosus. Only lunge and kettle swings showed peak EMG in the muscle-tendon unit lengthening phase and both these exercises involved faster speed. Conclusion Some exercises selectively activated the lateral and medial distal hamstrings. Low, medium, and high intensity exercises were demonstrated. This information enables the clinician, strength and conditioning coach and physiotherapist to better understand intensity- and muscle-specific activation during hamstring muscle rehabilitation. Therefore, these results may help in designing progressive strengthening and rehabilitation and prevention programs. PMID:26170726

Effect of Exercise Intensity on Neurotrophic Factors and Blood-Brain Barrier Permeability Induced by Oxidative-Nitrosative Stress in Male College Students.

PubMed

Roh, Hee-Tae; Cho, Su-Youn; Yoon, Hyung-Gi; So, Wi-Young

2017-06-01

We investigated the effects of aerobic exercise intensity on oxidative-nitrosative stress, neurotrophic factor expression, and blood-brain barrier (BBB) permeability. Fifteen healthy men performed treadmill running under low-intensity (LI), moderate-intensity (MI), and high-intensity (HI) conditions. Blood samples were collected immediately before exercise (IBE), immediately after exercise (IAE), and 60 min after exercise (60MAE) to examine oxidative-nitrosative stress (reactive oxygen species [ROS]; nitric oxide [NO]), neurotrophic factors (brain-derived neurotrophic factor [BDNF]; nerve growth factor [NGF]), and blood-brain barrier (BBB) permeability (S-100β; neuron-specific enolase). ROS concentration significantly increased IAE and following HI (4.9 ± 1.7 mM) compared with that after LI (2.8 ± 1.4 mM) exercise (p < .05). At 60MAE, ROS concentration was higher following HI (2.5 ± 1.2 mM) than after LI (1.5 ± 0.5 mM) and MI (1.4 ± 0.3 mM) conditions (p < .05). Plasma NO IAE increased significantly after MI and HI exercise (p < .05). Serum BDNF, NGF, and S-100b levels were significantly higher IAE following MI and HI exercise (p < .05). BDNF and S-100b were higher IAE following MI (29.6 ± 3.4 ng/mL and 87.1 ± 22.8 ng/L, respectively) and HI (31.4 ± 3.8 ng/mL and 100.6 ± 21.2 ng/L, respectively) than following LI (26.5 ± 3.0 ng/mL and 64.8 ± 19.2 ng/L, respectively) exercise (p < .05). 60MAE, S-100b was higher following HI (71.1 ± 14.5 ng/L) than LI (56.2 ± 14.7 ng/L) exercise (p < .05). NSE levels were not significantly different among all intensity conditions and time points (p > .05). Moderate- and/or high-intensity exercise may induce higher oxidative-nitrosative stress than may low-intensity exercise, which can increase peripheral neurotrophic factor levels by increasing BBB permeability.

Comparison of affective responses during and after low volume high-intensity interval exercise, continuous moderate- and continuous high-intensity exercise in active, untrained, healthy males.

PubMed

Niven, Ailsa; Thow, Jacqueline; Holroyd, Jack; Turner, Anthony P; Phillips, Shaun M

2018-09-01

This study compared affective responses to low volume high-intensity interval exercise (HIIE), moderate-intensity continuous exercise (MICE) and high-intensity continuous exercise (HICE). Twelve untrained males ([Formula: see text] 48.2 ± 6.7 ml·kg -1 ·min -1 ) completed MICE (30 min cycle at 85% of ventilatory threshold (VT)), HICE (cycle at 105% of VT matched with MICE for total work), and HIIE (10 x 6 s cycle sprints with 60 s recovery). Affective valence and perceived activation were measured before exercise, post warm-up, every 20% of exercise time, and 1, 5, 10, and 15 min post-exercise. Affective valence during exercise declined by 1.75 ± 2.42, 1.17 ± 1.99, and 0.42 ± 1.38 units in HICE, HIIE, and MICE, respectively, but was not statistically influenced by trial (P = 0.35), time (P = 0.06), or interaction effect (P = 0.08). Affective valence during HICE and HIIE was consistently less positive than MICE. Affective valence post-exercise was not statistically influenced by trial (P = 0.10) and at 5 min post-exercise exceeded end-exercise values (P = 0.048). Circumplex profiles showed no negative affect in any trial. Affective responses to low volume HIIE are similar to HICE but remain positive and rebound rapidly, suggesting it may be a potential alternative exercise prescription.

Effect of exercise intensity on post-exercise oxygen consumption and heart rate recovery.

PubMed

Mann, Theresa N; Webster, Christopher; Lamberts, Robert P; Lambert, Michael I

2014-09-01

There is some evidence that measures of acute post-exercise recovery are sensitive to the homeostatic stress of the preceding exercise and these measurements warrant further investigation as possible markers of training load. The current study investigated which of four different measures of metabolic and autonomic recovery was most sensitive to changes in exercise intensity. Thirty-eight moderately trained runners completed 20-min bouts of treadmill exercise at 60, 70 and 80% of maximal oxygen uptake (VO2max) and four different recovery measurements were determined: the magnitude of excess post-exercise oxygen consumption (EPOCMAG), the time constant of the oxygen consumption recovery curve (EPOCτ), heart rate recovery within 1 min (HRR60s) and the time constant of the heart rate recovery curve (HRRτ) . Despite significant differences in exercise parameters at each exercise intensity, only EPOCMAG showed significantly slower recovery with each increase in exercise intensity at the group level and in the majority of individuals. EPOCτ was significantly slower at 70 and 80% of VO₂max vs. 60% VO₂max and HRRτ was only significantly slower when comparing the 80 vs. 60% VO₂max exercise bouts. In contrast, HRR60s reflected faster recovery at 70 and 80% of VO₂max than at 60% VO₂max. Of the four recovery measurements investigated, EPOCMAG was the most sensitive to changes in exercise intensity and shows potential to reflect changes in the homeostatic stress of exercise at the group and individual level. Determining EPOCMAG may help to interpret the homeostatic stress of laboratory-based research trials or training sessions.

Serratus anterior and lower trapezius muscle activities during multi-joint isotonic scapular exercises and isometric contractions.

PubMed

Tsuruike, Masaaki; Ellenbecker, Todd S

2015-02-01

Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Cross-sectional study. Health Science Laboratory. A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited.

A Novel Time-Varying Spectral Filtering Algorithm for Reconstruction of Motion Artifact Corrupted Heart Rate Signals During Intense Physical Activities Using a Wearable Photoplethysmogram Sensor

PubMed Central

Salehizadeh, Seyed M. A.; Dao, Duy; Bolkhovsky, Jeffrey; Cho, Chae; Mendelson, Yitzhak; Chon, Ki H.

2015-01-01

Accurate estimation of heart rates from photoplethysmogram (PPG) signals during intense physical activity is a very challenging problem. This is because strenuous and high intensity exercise can result in severe motion artifacts in PPG signals, making accurate heart rate (HR) estimation difficult. In this study we investigated a novel technique to accurately reconstruct motion-corrupted PPG signals and HR based on time-varying spectral analysis. The algorithm is called Spectral filter algorithm for Motion Artifacts and heart rate reconstruction (SpaMA). The idea is to calculate the power spectral density of both PPG and accelerometer signals for each time shift of a windowed data segment. By comparing time-varying spectra of PPG and accelerometer data, those frequency peaks resulting from motion artifacts can be distinguished from the PPG spectrum. The SpaMA approach was applied to three different datasets and four types of activities: (1) training datasets from the 2015 IEEE Signal Process. Cup Database recorded from 12 subjects while performing treadmill exercise from 1 km/h to 15 km/h; (2) test datasets from the 2015 IEEE Signal Process. Cup Database recorded from 11 subjects while performing forearm and upper arm exercise. (3) Chon Lab dataset including 10 min recordings from 10 subjects during treadmill exercise. The ECG signals from all three datasets provided the reference HRs which were used to determine the accuracy of our SpaMA algorithm. The performance of the SpaMA approach was calculated by computing the mean absolute error between the estimated HR from the PPG and the reference HR from the ECG. The average estimation errors using our method on the first, second and third datasets are 0.89, 1.93 and 1.38 beats/min respectively, while the overall error on all 33 subjects is 1.86 beats/min and the performance on only treadmill experiment datasets (22 subjects) is 1.11 beats/min. Moreover, it was found that dynamics of heart rate variability can be accurately captured using the algorithm where the mean Pearson’s correlation coefficient between the power spectral densities of the reference and the reconstructed heart rate time series was found to be 0.98. These results show that the SpaMA method has a potential for PPG-based HR monitoring in wearable devices for fitness tracking and health monitoring during intense physical activities. PMID:26703618

A Novel Time-Varying Spectral Filtering Algorithm for Reconstruction of Motion Artifact Corrupted Heart Rate Signals During Intense Physical Activities Using a Wearable Photoplethysmogram Sensor.

PubMed

Salehizadeh, Seyed M A; Dao, Duy; Bolkhovsky, Jeffrey; Cho, Chae; Mendelson, Yitzhak; Chon, Ki H

2015-12-23

Accurate estimation of heart rates from photoplethysmogram (PPG) signals during intense physical activity is a very challenging problem. This is because strenuous and high intensity exercise can result in severe motion artifacts in PPG signals, making accurate heart rate (HR) estimation difficult. In this study we investigated a novel technique to accurately reconstruct motion-corrupted PPG signals and HR based on time-varying spectral analysis. The algorithm is called Spectral filter algorithm for Motion Artifacts and heart rate reconstruction (SpaMA). The idea is to calculate the power spectral density of both PPG and accelerometer signals for each time shift of a windowed data segment. By comparing time-varying spectra of PPG and accelerometer data, those frequency peaks resulting from motion artifacts can be distinguished from the PPG spectrum. The SpaMA approach was applied to three different datasets and four types of activities: (1) training datasets from the 2015 IEEE Signal Process. Cup Database recorded from 12 subjects while performing treadmill exercise from 1 km/h to 15 km/h; (2) test datasets from the 2015 IEEE Signal Process. Cup Database recorded from 11 subjects while performing forearm and upper arm exercise. (3) Chon Lab dataset including 10 min recordings from 10 subjects during treadmill exercise. The ECG signals from all three datasets provided the reference HRs which were used to determine the accuracy of our SpaMA algorithm. The performance of the SpaMA approach was calculated by computing the mean absolute error between the estimated HR from the PPG and the reference HR from the ECG. The average estimation errors using our method on the first, second and third datasets are 0.89, 1.93 and 1.38 beats/min respectively, while the overall error on all 33 subjects is 1.86 beats/min and the performance on only treadmill experiment datasets (22 subjects) is 1.11 beats/min. Moreover, it was found that dynamics of heart rate variability can be accurately captured using the algorithm where the mean Pearson's correlation coefficient between the power spectral densities of the reference and the reconstructed heart rate time series was found to be 0.98. These results show that the SpaMA method has a potential for PPG-based HR monitoring in wearable devices for fitness tracking and health monitoring during intense physical activities.

A Probability Model of Decompression Sickness at 4.3 Psia after Exercise Prebreathe

NASA Technical Reports Server (NTRS)

Conkin, Johnny; Gernhardt, Michael L.; Powell, Michael R.; Pollock, Neal

2004-01-01

Exercise PB can reduce the risk of decompression sickness on ascent to 4.3 psia when performed at the proper intensity and duration. Data are from seven tests. PB times ranged from 90 to 150 min. High intensity, short duration dual-cycle ergometry was done during the PB. This was done alone, or combined with intermittent low intensity exercise or periods of rest for the remaining PB. Nonambulating men and women performed light exercise from a semi-recumbent position at 4.3 psia for four hrs. The Research Model with age tested the probability that DCS increases with advancing age. The NASA Model with gender hypothesized that the probability of DCS increases if gender is female. Accounting for exercise and rest during PB with a variable half-time compartment for computed tissue N2 pressure advances our probability modeling of hypobaric DCS. Both models show that a small increase in exercise intensity during PB reduces the risk of DCS, and a larger increase in exercise intensity dramatically reduces risk. These models support the hypothesis that aerobic fitness is an important consideration for the risk of hypobaric DCS when exercise is performed during the PB.

Muscle performance following an acute bout of plyometric training combined with low or high intensity weight exercise.

PubMed

Beneka, Anastasia G; Malliou, Paraskevi K; Missailidou, Victoria; Chatzinikolaou, Athanasios; Fatouros, Ioannis; Gourgoulis, Vassilios; Georgiadis, Elias

2013-01-01

To determine the time course of performance responses after an acute bout of plyometric exercise combined with high and low intensity weight training, a 3-group (including a control group), repeated-measures design was employed. Changes in performance were monitored through jumping ability by measuring countermovement and squat jumping, and strength performance assessment through isometric and isokinetic testing of knee extensors (at two different velocities). Participants in both experimental groups performed a plyometric protocol consisting of 50 jumps over 50 cm hurdles and 50 drop jumps from a 50 cm plyometric box. Additionally, each group performed two basic weight exercises consisting of leg presses and leg extensions at 90-95% of maximum muscle strength for the high intensity group and 60% of maximum muscle strength for the low intensity group. The results of the study suggest that an acute bout of intense plyometric exercise combined with weight exercise induces time-dependent changes in performance, which are also dependent on the nature of exercise protocol and testing procedures. In conclusion, acute plyometric exercise with weight exercise may induce a substantial decline in jumping performance for as long as 72 hours but not in other forms of muscle strength.

Synergistic effects of low-intensity exercise conditioning and β-blockade on cardiovascular and autonomic adaptation in pre- and postmenopausal women with hypertension.

PubMed

Goldie, Catherine L; Brown, C Ann; Hains, Sylvia M J; Parlow, Joel L; Birtwhistle, Richard

2013-10-01

The effects of a 12-week low-intensity exercise conditioning program (walking) on blood pressure (BP), heart rate (HR), rate-pressure product (RPP), and cardiac autonomic function were measured in 40 sedentary women with hypertension. Women were assigned to either an exercise group (n = 20) or a control group (n = 20), matched for β-blockade treatment. They underwent testing at the beginning and at the end of the 12-week study period in three conditions: supine rest, standing, and low-intensity steady state exercise. The exercise group participated in a 12-week, low-intensity walking program, while the control group continued with usual sedentary activity. Compared with the control group, women in the exercise group showed reductions in systolic and diastolic BP and RPP (i.e., the estimated cardiac workload). β-Blockers increased baroreflex sensitivity and lowered BP and HR in all participants; however, those in the exercise group showed the effects of both treatments: a greater reduction in HR and RPP. The combination of exercise training and β-blockade produces cardiac and autonomic adaptations that are not observed with either treatment alone, suggesting that β-blockade enhances the conditioning effects of low-intensity exercise in women with hypertension.

Moderate intensity exercise as an adjunct to standard smoking cessation treatment for women: a pilot study.

PubMed

Williams, David M; Whiteley, Jessica A; Dunsiger, Shira; Jennings, Ernestine G; Albrecht, Anna E; Ussher, Michael H; Ciccolo, Joseph T; Parisi, Alfred F; Marcus, Bess H

2010-06-01

Previous randomized controlled trials have not supported moderate intensity exercise as an efficacious adjunct to smoking cessation treatments for women; however, compliance with exercise programs in these studies has been poor. The purpose of this pilot study was to estimate the effects of moderate intensity exercise on smoking cessation outcomes under optimal conditions for exercise program compliance. Sixty previously sedentary, healthy, female smokers were randomized to an 8-week program consisting of brief baseline smoking cessation counseling and the nicotine patch plus either 150 min/week of moderate intensity exercise or contact control. Participants attended a median of 86.4% and 95.5% of prescribed exercise/control sessions, respectively. There was a moderate, though statistically nonsignificant, effect of exercise at post-treatment for objectively verified 7-day point prevalence abstinence (48.3% vs. 23.3%; OR = 3.07, 95% CI: 0.89-11.07) and prolonged abstinence (34.5% vs. 20.0%; OR = 2.11, 95% CI: 0.56-8.32). Effects were attenuated when controlling for potential confounders, and after a 1-month, no-treatment period. The findings provide a preliminary indication that, given adequate compliance, moderate intensity exercise may enhance short-term smoking cessation outcomes for women; however, a larger trial is warranted. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

Skeletal muscle fatigue precedes the slow component of oxygen uptake kinetics during exercise in humans.

PubMed

Cannon, Daniel T; White, Ailish C; Andriano, Melina F; Kolkhorst, Fred W; Rossiter, Harry B

2011-02-01

The mechanisms determining exercise intolerance are poorly understood. A reduction in work efficiency in the form of an additional energy cost and oxygen requirement occurs during high-intensity exercise and contributes to exercise limitation. Muscle fatigue and subsequent recruitment of poorly efficient muscle fibres has been proposed to mediate this decline. These data demonstrate in humans, that muscle fatigue, generated in the initial minutes of exercise, is correlated with the increasing energy demands of high-intensity exercise. Surprisingly, however, while muscle fatigue reached a plateau, oxygen uptake continued to increase throughout 8 min of exercise. This suggests that additional recruitment of inefficient muscle fibres may not be the sole mechanism contributing to the decline in work efficiency during high-intensity exercise.

Virtual and live social facilitation while exergaming: competitiveness moderates exercise intensity.

PubMed

Snyder, Amanda L; Anderson-Hanley, Cay; Arciero, Paul J

2012-04-01

Grounded in social facilitation theory, this study compared the impact on exercise intensity of a virtual versus a live competitor, when riding a virtual reality-enhanced stationary bike ("cybercycle"). It was hypothesized that competitiveness would moderate effects. Twenty-three female college students were exposed to three conditions on a cybercycle: solo training, virtual competitor, and live competitor. After training without a competitor (solo condition for familiarization with equipment), participants competed against a virtual avatar or live rider (random order of presentation). A repeated-measures analysis revealed a significant condition (virtual/live) by competitiveness (high/low) interaction for exercise intensity (watts). More competitive participants exhibited significantly greater exercise intensity when competing against a live versus virtual competitor. The implication is that live competitors can have an added social facilitation effect and influence exercise intensity, although competitiveness moderates this effect.

Effects of exercise training alone vs a combined exercise and nutritional lifestyle intervention on glucose homeostasis in prediabetic individuals: a randomised controlled trial.

PubMed

Slentz, Cris A; Bateman, Lori A; Willis, Leslie H; Granville, Esther O; Piner, Lucy W; Samsa, Gregory P; Setji, Tracy L; Muehlbauer, Michael J; Huffman, Kim M; Bales, Connie W; Kraus, William E

2016-10-01

Although the Diabetes Prevention Program (DPP) established lifestyle changes (diet, exercise and weight loss) as the 'gold standard' preventive therapy for diabetes, the relative contribution of exercise alone to the overall utility of the combined diet and exercise effect of DPP is unknown; furthermore, the optimal intensity of exercise for preventing progression to diabetes remains very controversial. To establish clinical efficacy, we undertook a study (2009 to 2013) to determine: how much of the effect on measures of glucose homeostasis of a 6 month programme modelled after the first 6 months of the DPP is due to exercise alone; whether moderate- or vigorous-intensity exercise is better for improving glucose homeostasis; and to what extent amount of exercise is a contributor to improving glucose control. The primary outcome was improvement in fasting plasma glucose, with improvement in plasma glucose AUC response to an OGTT as the major secondary outcome. The trial was a parallel clinical trial. Sedentary, non-smokers who were 45-75 year old adults (n = 237) with elevated fasting glucose (5.28-6.94 mmol/l) but without cardiovascular disease, uncontrolled hypertension, or diabetes, from the Durham area, were studied at Duke University. They were randomised into one of four 6 month interventions: (1) low amount (42 kJ kg body weight(-1) week(-1) [KKW])/moderate intensity: equivalent of expending 42 KKW (e.g. walking ∼16 km [8.6 miles] per week) with moderate-intensity (50% [Formula: see text]) exercise; (2) high amount (67 KKW)/moderate intensity: equivalent of expending 67 KKW (∼22.3 km [13.8 miles] per week) with moderate-intensity exercise; (3) high amount (67 KKW)/vigorous intensity: equivalent to group 2, but with vigorous-intensity exercise (75% [Formula: see text]); and (4) diet + 42 KKW moderate intensity: same as group 1 but with diet and weight loss (7%) to mimic the first 6 months of the DPP. Computer-generated randomisation lists were provided by our statistician (G. P. Samsa). The randomisation list was maintained by L. H. Willis and C. A. Slentz with no knowledge of or input into the scheduling, whereas all scheduling was done by L. A. Bateman, with no knowledge of the randomisation list. Subjects were automatically assigned to the next group listed on the randomisation sheet (with no ability to manipulate the list order) on the day that they came in for the OGTT, by L. H. Willis. All plasma analysis was done blinded by the individuals doing the measurements (i.e. lipids, glucose, insulin). Subjects and research staff (other than individuals analysing the blood) were not blinded to the group assignments. Number randomised, completers and number analysed with complete OGTT data for each group were: low-amount/moderate-intensity (61, 43, 35); high-amount/moderate-intensity (61, 44, 40); high-amount/vigorous-intensity (61, 43, 38); diet/exercise (54, 45, 37), respectively. Only the diet and exercise group experienced a decrease in fasting glucose (p < 0.001). The means and 95% CIs for changes in fasting glucose (mmol/l) for each group were: high-amount/moderate-intensity -0.07 (-0.20, 0.06); high-amount/vigorous 0.06 (-0.07, 0.19); low-amount/moderate 0.05 (-0.05, 0.15); and diet/exercise -0.32 (-0.46, -0.18). The effects sizes for each group (in the same order) were: 0.17, 0.15, 0.18 and 0.71, respecively. For glucose tolerance (glucose AUC of OGTT), similar improvements were observed for the diet and exercise (8.2% improvement, effect size 0.73) and the 67 KKW moderate-intensity exercise (6.4% improvement, effect size 0.60) groups; moderate-intensity exercise was significantly more effective than the same amount of vigorous-intensity exercise (p < 0.0207). The equivalent amount of vigorous-intensity exercise alone did not significantly improve glucose tolerance (1.2% improvement, effect size 0.21). Changes in insulin AUC, fasting plasma glucose and insulin did not differ among the exercise groups and were numerically inferior to the diet and exercise group. In the present clinical efficacy trial we found that a high amount of moderate-intensity exercise alone was very effective at improving oral glucose tolerance despite a relatively modest 2 kg change in body fat mass. These data, combined with numerous published observations of the strong independent relation between postprandial glucose concentrations and prediction of future diabetes, suggest that walking ∼18.2 km (22.3 km prescribed with 81.6% adherence in the 67 KKW moderate-intensity group) per week may be nearly as effective as a more intensive multicomponent approach involving diet, exercise and weight loss for preventing the progression to diabetes in prediabetic individuals. These findings have important implications for the choice of clinical intervention to prevent progression to type 2 diabetes for those at high risk. ClinicalTrials.gov NCT00962962 FUNDING: The study was funded by National Institutes for Health National Institute of Diabetes and Digestive and Kidney Diseases (NIH-NDDK) (R01DK081559).

Melatonin Supplementation Ameliorates Energy Charge and Oxidative Stress Induced by Acute Exercise in Rat Heart Tissue

PubMed Central

Cimen, Behzat; Uz, Ali; Cetin, Ihsan; Cimen, Leyla; Cetin, Aysun

2017-01-01

Background Regular physical exercises may help people to be more resistant to everyday problems; however, how acute and intense exercises affect the heart tissues functioning with maximum capacity and how melatonin changes the effect of acute and intense exercises are still not obvious. We aimed to comprehend whether melatonin intravenous injection supports the oxidative/antioxidative conditions and energy charge in heart tissues of rats exposed to acute swimming exercise. Methods Thirty Wistar-albino male rats were categorized into 3 groups with equal number of subjects. Control group performed no application, and acute intensive swimming exercise group were subjected to acute intensive swimming exercise for 30 minutes, and melatonin group were applied 25 mg/kg single dose melatonin administration prior to 30 minutes acute intensive swimming exercise. The levels of malondialdehyde (MDA), and superoxide dismutase, catalase and glutathione peroxidase activities were measured by spectrophotometric method; and the levels of 3-nitrotyrosine (3-NT) and energy charge were determined by a high performance liquid chromatography. Results Tissue MDA and 3-NT levels of the acute intensive exercise group were found to be higher than the control group. It was also found that the melatonin administration increased the energy charge and antioxidant activities, while decreased tissue MDA and 3-NT levels in heart tissues. Our results provide evidence for melatonin that can exert potent protective effects on oxidative stress and energy charge for heart tissues in acute swimming exercise. Conclusions These findings suggest that the direct beneficial effects of melatonin could be potentially applied on prevention of oxidative stress and energy deficit. PMID:28959107

Intense physical exercise potentiates glucose inhibitory effect over food intake of male Wistar rats.

PubMed

Cavalcanti-de-Albuquerque, Joao Paulo; Kincheski, Grasielle Clotildes; Louzada, Ruy Andrade; Galina, Antônio; Pierucci, Anna Paola Trindade Rocha; Carvalho, Denise P

2018-06-12

What is the central question of this study? Physical exercise has emerged as a non-pharmacological treatment for obesity by promoting changes in energy balance. Despite the accumulated knowledge about exercise effects on energy expenditure, the central question of this study is to understand how an acute session of exercise might affect food intake of male Wistar rats. What is the main finding? The main finding of this work is that food intake in male Wistar rats is decreased in the first hour after physical exercise independent of the intensity. Moreover, high-intensity exercise potentiates the anorexic effect of peripheral glucose administration. Obesity has emerged as a critical metabolic disorder in modern society. An adequate lifestyle with good-oriented programs of diet and physical exercise (PE) can prevent or potentially even cure obesity. Additionally, PE might lead to weight loss by increasing energy expenditure and decreasing hunger perception. In this manuscript, we hypothesize that an acute exercise session with different intensities would potentiate the glucose inhibitory effects on food intake in male Wistar rats. Our data show that moderate- (MOD) or high-intensity (HIGH) PE significantly decreased food intake, although no changes in the expression of feeding-related neuropeptide in the arcuate nucleus of the hypothalamus were found. Exercised animals demonstrated a reduced glucose tolerance and increased blood insulin concentration. Intraperitoneal administration of glucose decreased food intake in control animals. In the animals submitted to MOD, the decrease in food intake promoted by glucose was similar to controls; however, an interaction was observed when glucose was injected in the HIGH group, in which food intake was significantly lower than the effect produced by glucose alone. A different pattern of expression was observed for the monocarboxylate transporter isoforms (MCT1, 2 and 4) and the 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKBP3) in the hypothalamus, which was dependent on the exercise intensity. In conclusion, PE decreases food intake independently of the intensity. However, an interaction between PE and the anorexic effect of glucose is only observed when a high-intensity exercise is performed. These data show an essential role of exercise intensity in the modulation of glucose inhibitory effect on food intake. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Comparison of Consumer and Research Monitors under Semistructured Settings.

PubMed

Bai, Yang; Welk, Gregory J; Nam, Yoon Ho; Lee, Joey A; Lee, Jung-Min; Kim, Youngwon; Meier, Nathan F; Dixon, Philip M

2016-01-01

This study evaluated the relative validity of different consumer and research activity monitors during semistructured periods of sedentary activity, aerobic exercise, and resistance exercise. Fifty-two (28 male and 24 female) participants age 18-65 yr performed 20 min of self-selected sedentary activity, 25 min of aerobic exercise, and 25 min of resistance exercise, with 5 min of rest between each activity. Each participant wore five wrist-worn consumer monitors [Fitbit Flex, Jawbone Up24, Misfit Shine (MS), Nike+ Fuelband SE (NFS), and Polar Loop] and two research monitors [ActiGraph GT3X+ on the waist and BodyMedia Core (BMC) on the arm] while being concurrently monitored with Oxycon Mobile (OM), a portable metabolic measuring system. Energy expenditure (EE) on different activity sessions was measured by OM and estimated by all monitors. Mean absolute percent error (MAPE) values for the full 80-min protocol ranged from 15.3% (BMC) to 30.4% (MS). EE estimates from ActiGraph GT3X+ were found to be equivalent to those from OM (± 10% equivalence zone, 285.1-348.5). Correlations between OM and the various monitors were generally high (ranged between 0.71 and 0.90). Three monitors had MAPE values lower than 20% for sedentary activity: BMC (15.7%), MS (18.2%), and NFS (20.0%). Two monitors had MAPE values lower than 20% for aerobic exercise: BMC (17.2%) and NFS (18.5%). None of the monitors had MAPE values lower than 25% for resistance exercise. Overall, the research monitors and Fitbit Flex, Jawbone Up24, and NFS provided reasonably accurate total EE estimates at the individual level. However, larger error was evident for individual activities, especially resistance exercise. Further research is needed to examine these monitors across various activities and intensities as well as under real-world conditions.

THE ACUTE EFFECTS OF CONCENTRIC VERSUS ECCENTRIC MUSCLE FATIGUE ON SHOULDER ACTIVE REPOSITIONING SENSE

PubMed Central

2017-01-01

Purpose/Background Shoulder proprioception is essential in the activities of daily living as well as in sports. Acute muscle fatigue is believed to cause a deterioration of proprioception, increasing the risk of injury. The purpose of this study was to evaluate if fatigue of the shoulder external rotators during eccentric versus concentric activity affects shoulder joint proprioception as determined by active reproduction of position. Study design Quasi-experimental trial. Methods Twenty-two healthy subjects with no recent history of shoulder pathology were randomly allocated to either a concentric or an eccentric exercise group for fatiguing the shoulder external rotators. Proprioception was assessed before and after the fatiguing protocol using an isokinetic dynamometer, by measuring active reproduction of position at 30 ° of shoulder external rotation, reported as absolute angular error. The fatiguing protocol consisted of sets of fifteen consecutive external rotator muscle contractions in either the concentric or eccentric action. The subjects were exercised until there was a 30% decline from the peak torque of the subjects’ maximal voluntary contraction over three consecutive muscle contractions. Results A one-way analysis of variance test revealed no statistical difference in absolute angular error (p > 0.05) between concentric and eccentric groups. Moreover, no statistical difference (p > 0.05) was found in absolute angular error between pre- and post-fatigue in either group. Conclusions Eccentric exercise does not seem to acutely affect shoulder proprioception to a larger extent than concentric exercise. Level of evidence 2b PMID:28515976

Subjective Measures of Exercise Intensity to Gauge Substrate Partitioning in Persons With Paraplegia

PubMed Central

Kressler, Jochen; Cowan, Rachel E.; Ginnity, Kelly; Nash, Mark S.

2012-01-01

Background: The Borg Rating of Perceived Exertion (RPE) Scale and talk test (TT) are commonly recommended for persons to gauge exercise intensity. It is not known whether they are suitable to estimate substrate partitioning between carbohydrate and fat in persons with SCI. Objective: Investigate substrate partitioning/utilization patterns associated with RPE and TT. Methods: Twelve participants with chronic paraplegia underwent 2 arm crank exercise tests on nonconsecutive days within 2 weeks. Test 1 was a graded exercise test (GXT) to volitional exhaustion. Test 2 was a 15-minute self-selected steady state (SS) voluntary arm exercise bout simulating a brief, yet typical exercise session. Results: For the GXT, very light intensity exercise (RPE < 9) and TT stage before last positive were associated with highest contribution of fat oxidation (~35%-50%) to total energy expenditure (TEE). Fat oxidation was low at all stages, with the highest rate (0.13 ± 0.07 g/min) occurring at stage 1 (10 W). Corresponding average RPE was 7 ± 2 and the TT was positive for all participants at this stage. For the SS, fuel partitioning throughout exercise was dominated by carbohydrate oxidation (1.47 ± 0.08 g/min), accounting for almost all (~94%) of TEE with only a minute contribution from fat oxidation (0.02 ± 0.004 g/min). A positive TT was associated with an average contribution of fat oxidation of ~10%. Conclusions: RPE but not the TT appears suitable to predict exercise intensities associated with the highest levels of fat oxidation. However, such intensities are below authoritative intensity thresholds for cardiorespiratory fitness promotion, and therefore the applicability of such a prediction for exercise prescriptions is likely limited to individuals with low exercise tolerance. PMID:23459243

Effect of high-intensity interval exercise on lipid oxidation during postexercise recovery.

PubMed

Malatesta, Davide; Werlen, Catherine; Bulfaro, Stefano; Chenevière, Xavier; Borrani, Fabio

2009-02-01

The aim of this study was to examine whether lipid oxidation predominates during 3 h of postexercise recovery in high-intensity interval exercise as compared with moderate-intensity continuous exercise on a cycle ergometer in fit young men (n = 12; 24.6 +/- 0.6 yr). The energy substrate partitioning was evaluated during and after high-intensity submaximal interval exercise (INT, 1-min intervals at 80% of maximal aerobic power output [Wmax] with an intervening 1 min of active recovery at 40% Wmax) and 60-min moderate-intensity continuous exercise at 45% of maximal oxygen uptake (C45%) as well as a time-matched resting control trial (CON). Exercise bouts were matched for mechanical work output. During exercise, a significantly greater contribution of CHO and a lower contribution of lipid to energy expenditure were found in INT (512.7 +/- 26.6 and 41.0 +/- 14.0 kcal, respectively) than in C45% (406.3 +/- 21.2 and 170.3 +/- 24.0 kcal, respectively; P < 0.001) despite similar overall energy expenditure in both exercise trials (P = 0.13). During recovery, there were no significant differences between INT and C45% in substrate turnover and oxidation (P > 0.05). On the other hand, the mean contribution of lipids to energy yield was significantly higher after exercise trials (C45% = 61.3 +/- 4.2 kcal; INT = 66.7 +/- 4.7 kcal) than after CON (51.5 +/- 3.4 kcal; P < 0.05). These findings show that lipid oxidation during postexercise recovery was increased by a similar amount on two isoenergetic exercise bouts of different forms and intensities compared with the time-matched no-exercise control trial.

Impact of aerobic exercise intensity on craving and reactivity to smoking cues.

PubMed

Janse Van Rensburg, Kate; Elibero, Andrea; Kilpatrick, Marcus; Drobes, David J

2013-06-01

Aerobic exercise can acutely reduce cigarette cravings during periods of nicotine deprivation. The primary aim of this study was to assess the differential effects of light and vigorous intensity aerobic exercise on cigarette cravings, subjective and physiological reactivity to smoking cues, and affect after overnight nicotine deprivation. A secondary aim was to examine cortisol change as a mediator of the effects of exercise on smoking motivation. 162 (55 female, 107 male) overnight nicotine-deprived smokers were randomized to one of three exercise conditions: light intensity, vigorous intensity, or a passive control condition. After each condition, participants engaged in a standardized cue reactivity assessment. Self-reported urges to smoke, affect, and salivary cortisol were assessed at baseline (i.e., before each condition), immediately after each condition, and after the cue reactivity assessment. Light and vigorous exercise significantly decreased urges to smoke and increased positive affect, relative to the control condition. In addition, those in the vigorous exercise condition demonstrated suppressed appetitive reactivity to smoking cues, as indexed by the startle eyeblink reflex. Although exercise intensity was associated with expected changes in cortisol concentration, these effects were not related to changes in craving or cue reactivity. Both light and vigorous exercise can reduce general cravings to smoke, whereas vigorous exercise appears especially well-suited for reducing appetitive reactions to cues that may precede smoking. Results did not support exercise-induced cortisol release as a mechanism for these effects. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Cardiorespiratory fitness modulates the acute flow-mediated dilation response following high-intensity but not moderate-intensity exercise in elderly men.

PubMed

Bailey, Tom G; Perissiou, Maria; Windsor, Mark; Russell, Fraser; Golledge, Jonathan; Green, Daniel J; Askew, Christopher D

2017-05-01

Impaired endothelial function is observed with aging and in those with low cardiorespiratory fitness (V̇o 2peak ). Improvements in endothelial function with exercise training are somewhat dependent on the intensity of exercise. While the acute stimulus for this improvement is not completely understood, it may, in part, be due to the flow-mediated dilation (FMD) response to acute exercise. We examined the hypothesis that exercise intensity alters the brachial (systemic) FMD response in elderly men and is modulated by V̇o 2peak Forty-seven elderly men were stratified into lower (V̇o 2peak = 24.3 ± 2.9 ml·kg -1 ·min -1 ; n = 27) and higher fit groups (V̇o 2peak = 35.4 ± 5.5 ml·kg -1 ·min -1 ; n = 20) after a test of cycling peak power output (PPO). In randomized order, participants undertook moderate-intensity continuous exercise (MICE; 40% PPO) or high-intensity interval cycling exercise (HIIE; 70% PPO) or no-exercise control. Brachial FMD was assessed at rest and 10 and 60 min after exercise. FMD increased after MICE in both groups {increase of 0.86% [95% confidence interval (CI), 0.17-1.56], P = 0.01} and normalized after 60 min. In the lower fit group, FMD was reduced after HIIE [reduction of 0.85% (95% CI, 0.12-1.58), P = 0.02] and remained decreased at 60 min. In the higher fit group, FMD was unchanged immediately after HIIE and increased after 60 min [increase of 1.52% (95% CI, 0.41-2.62), P < 0.01, which was correlated with V̇o 2peak , r = 0.41; P < 0.01]. In the no-exercise control, FMD was reduced in both groups after 60 min ( P = 0.05). Exercise intensity alters the acute FMD response in elderly men and V̇o 2peak modulates the FMD response following HIIE but not MICE. The sustained decrease in FMD in the lower fit group following HIIE may represent a signal for vascular adaptation or endothelial fatigue. NEW & NOTEWORTHY This study is the first to show that moderate-intensity continuous cycling exercise increased flow-mediated dilation (FMD) transiently before normalization of FMD after 1 h, irrespective of cardiorespiratory fitness level in elderly men. Interestingly, we show increased FMD after high-intensity cycling exercise in higher fit men, with a sustained reduction in FMD in lower fit men. The prolonged reduction in FMD after high-intensity cycling exercise may be associated with future vascular adaptation but may also reflect a period of increased cardiovascular risk in lower fit elderly men. Copyright © 2017 the American Physiological Society.

Effect of long-term exercise training on blood viscosity during endurance exercise at an anaerobic threshold intensity.

PubMed

Adachi, H; Sakurai, S; Tanehata, M; Oshima, S; Taniguchi, K

2000-11-01

Blood viscosity (etaB) is low in athletes, but the effect of exercise training on etaB during endurance exercise at an anaerobic threshold (AT) intensity in non-athletes is not well known, although it is known that exercise training sometimes induces the hyperviscosity syndrome. Fourteen subjects were recruited and divided into 2 groups: those who trained at an AT intensity for 30 min/day, 3 times weekly for 1 year (Group T, n=8), and sedentary subjects (Group C, n=6). The test protocol consisted of a single 30-min treadmill exercise at each individual's AT intensity, which was determined in advance. The etaB, plasma viscosity (etaP), and hematocrit were measured just before and at the end of the treadmill exercise. The subjects were not allowed to drink any water before exercise. In the Group C subjects, the hematocrit and etaP increased significantly and the etaB tended to increase. However, in the Group T subjects, the hematocrit and etaP did not increase and the etaB decreased significantly. These data indicate that long-term exercise training attenuates the increase in blood viscosity during exercise.

Blood Pressure Response to Exercise and Cardiovascular Disease.

PubMed

Schultz, Martin G; La Gerche, Andre; Sharman, James E

2017-10-18

This review aimed to provide a clinical update on exercise blood pressure (BP) and its relationship to cardiovascular disease (CVD), outlining key determinants of abnormal exercise BP responses. We also highlight current evidence gaps that need addressing in order to optimise the relevance of exercise BP as clinical CVD risk factor. Abnormal exercise BP manifests as either exercise hypotension (low BP response) or as exaggerated exercise BP (high BP response). Exercise hypotension is an established sign of existing and likely severe CVD, but exaggerated exercise BP also carries elevated CVD risk due to its association with sub-clinical hypertension. Although exaggerated exercise BP is related to heightened CVD risk at any exercise intensity, recent data suggest that the BP response to submaximal intensity exercise holds greater prognostic and clinical significance than BP achieved at peak/maximal intensity exercise. Cardiorespiratory fitness is a strong modifier of the exercise BP response, and should be taken into consideration when assessing the association with CVD. Both exercise hypotension and exaggerated exercise BP serve as markers that should prompt evaluation for potential underlying CVD. However, the clinical utility of these markers is currently inhibited by the lack of consensus informing the definitions and thresholds for abnormalities in exercise BP.

High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: implications for exercise adherence.

PubMed

Bartlett, Jonathan D; Close, Graeme L; MacLaren, Don P M; Gregson, Warren; Drust, Barry; Morton, James P

2011-03-01

The aim of this study was to objectively quantify ratings of perceived enjoyment using the Physical Activity Enjoyment Scale following high-intensity interval running versus moderate-intensity continuous running. Eight recreationally active men performed two running protocols consisting of high-intensity interval running (6 × 3 min at 90% VO(2max) interspersed with 6 × 3 min active recovery at 50% VO(2max) with a 7-min warm-up and cool down at 70% VO(2max)) or 50 min moderate-intensity continuous running at 70% VO(2max). Ratings of perceived enjoyment after exercise were higher (P < 0.05) following interval running compared with continuous running (88 ± 6 vs. 61 ± 12) despite higher (P < 0.05) ratings of perceived exertion (14 ± 1 vs. 13 ± 1). There was no difference (P < 0.05) in average heart rate (88 ± 3 vs. 87 ± 3% maximum heart rate), average VO(2) (71 ± 6 vs. 73 ± 4%VO(2max)), total VO(2) (162 ± 16 vs. 166 ± 27 L) or energy expenditure (811 ± 83 vs. 832 ± 136 kcal) between protocols. The greater enjoyment associated with high-intensity interval running may be relevant for improving exercise adherence, since running is a low-cost exercise intervention requiring no exercise equipment and similar relative exercise intensities have previously induced health benefits in patient populations.

Practical Approaches to Prescribing Physical Activity and Monitoring Exercise Intensity.

PubMed

Reed, Jennifer L; Pipe, Andrew L

2016-04-01

Regular physical activity helps to prevent heart disease, and reduces the risk of first or subsequent cardiovascular events. It is recommended that Canadian adults accumulate at least 150 minutes of moderate- to vigorous-intensity aerobic exercise per week, in bouts of 10 minutes or more, and perform muscle- and bone-strengthening activities at least 2 days per week. Individual exercise prescriptions can be developed using the frequency, intensity, time, and type principles. Increasing evidence suggests that high-intensity interval training is efficacious for a broad spectrum of heart health outcomes. Several practical approaches to prescribing and monitoring exercise intensity exist including: heart rate monitoring, the Borg rating of perceived exertion scale, the Talk Test, and, motion sensors. The Borg rating of perceived exertion scale matches a numerical value to an individual's perception of effort, and can also be used to estimate heart rate. The Talk Test, the level at which simple conversation is possible, can be used to monitor desired levels of moderate- to vigorous-intensity exercise. Motion sensors can provide users with practical and useful exercise training information to aid in meeting current exercise recommendations. These approaches can be used by the public, exercise scientists, and clinicians to easily and effectively guide physical activity in a variety of settings. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Two-dimensional strain echocardiography technology for evaluation of myocardial strain in swimming athletes after high-intensity exercise.

PubMed

Liang, Chen; Ma, Yun; Gao, Can; Zhang, Jianhong; Yang, Min; Chen, Gen; Fu, Shan; Zhu, Tiangang

2017-02-01

The aim of this study was to investigate the change in myocardial strain in swimming athletes before and after high-intensity exercise using two-dimensional strain echocardiography (2DSE) technology. To assess whether the local and overall myocardial function and myocardial injury are accurately measured using 2DSE technology, 15 swimming athletes were selected as research objects. We applied 2DSE technology to track the 2D ultrasound images of the apical four chambers, the apical two chambers, and the apical long axis before and after high-intensity, increasing-load exercise. We recorded indices such as the left ventricular global strain (GS) and the left ventricular segmental wall longitudinal peak systolic strain (PS) in 18 systoles and analyzed the myocardial strain change before and after exercise. After high-intensity exercise, the overall myocardial strain decreased, especially the strain of the posterior wall, posterior divider, lateral wall, lower wall, and the basal and middle segments of the anterior wall. The influence of exercise on myocardial strain was greater on the basal and middle segments than on the apical segment. One-time intensive exercise negatively affected the myocardial muscle. Myocardial muscles in the apical segment and the myocardial wall were more sensitive to intensive exercise. The 2DSE technology can precisely position the motion-sensitive areas and help locate myocardial injury. © 2017, Wiley Periodicals, Inc.

The Assessment of Muscular Effort, Fatigue, and Physiological Adaptation Using EMG and Wavelet Analysis.

PubMed

Graham, Ryan B; Wachowiak, Mark P; Gurd, Brendon J

2015-01-01

Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is a transcription factor co-activator that helps coordinate mitochondrial biogenesis within skeletal muscle following exercise. While evidence gleaned from submaximal exercise suggests that intracellular pathways associated with the activation of PGC-1α, as well as the expression of PGC-1α itself are activated to a greater extent following higher intensities of exercise, we have recently shown that this effect does not extend to supramaximal exercise, despite corresponding increases in muscle activation amplitude measured with electromyography (EMG). Spectral analyses of EMG data may provide a more in-depth assessment of changes in muscle electrophysiology occurring across different exercise intensities, and therefore the goal of the present study was to apply continuous wavelet transforms (CWTs) to our previous data to comprehensively evaluate: 1) differences in muscle electrophysiological properties at different exercise intensities (i.e. 73%, 100%, and 133% of peak aerobic power), and 2) muscular effort and fatigue across a single interval of exercise at each intensity, in an attempt to shed mechanistic insight into our previous observations that the increase in PGC-1α is dissociated from exercise intensity following supramaximal exercise. In general, the CWTs revealed that localized muscle fatigue was only greater than the 73% condition in the 133% exercise intensity condition, which directly matched the work rate results. Specifically, there were greater drop-offs in frequency, larger changes in burst power, as well as greater changes in burst area under this intensity, which were already observable during the first interval. As a whole, the results from the present study suggest that supramaximal exercise causes extreme localized muscular fatigue, and it is possible that the blunted PGC-1α effects observed in our previous study are the result of fatigue-associated increases in muscle acidosis. This should be explored in future research using further combinations of EMG and muscle biochemistry and histology.

End-exercise ΔHHb/ΔVO2 and post-exercise local oxygen availability in relation to exercise intensity.

PubMed

Stöcker, F; Von Oldershausen, C; Paternoster, F K; Schulz, T; Oberhoffer, R

2017-07-01

Increased local blood supply is thought to be one of the mechanisms underlying oxidative adaptations to interval training regimes. The relationship of exercise intensity with local blood supply and oxygen availability has not been sufficiently evaluated yet. The aim of this study was to examine the effect of six different intensities (40-90% peak oxygen uptake, VO 2peak ) on relative changes in oxygenated, deoxygenated and total haemoglobin (ΔO 2 Hb, ΔHHb, ΔTHb) concentration after exercise as well as end-exercise ΔHHb/ΔVO 2 as a marker for microvascular O 2 distribution. Seventeen male subjects performed an experimental protocol consisting of 3 min cycling bouts at each exercise intensity in randomized order, separated by 5 min rests. ΔO 2 Hb and ΔHHb were monitored with near-infrared spectroscopy of the vastus lateralis muscle, and VO 2 was assessed. ΔHHb/ΔVO 2 increased significantly from 40% to 60% VO 2 peak and decreased from 60% to 90% VO 2 peak. Post-exercise ΔTHb and ΔO 2 Hb showed an overshoot in relation to pre-exercise values, which was equal after 40-60% VO 2peak and rose significantly thereafter. A plateau was reached following exercise at ≥80% VO 2peak . The results suggest that there is an increasing mismatch of local O 2 delivery and utilization during exercise up to 60% VO 2peak . This insufficient local O 2 distribution is progressively improved above that intensity. Further, exercise intensities of ≥80% VO 2peak induce highest local post-exercise O 2 availability. These effects are likely due to improved microvascular perfusion by enhanced vasodilation, which could be mediated by higher lactate production and the accompanying acidosis. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Measuring stroke patients' exercise preferences using a discrete choice experiment.

PubMed

Geidl, Wolfgang; Knocke, Katja; Schupp, Wilfried; Pfeifer, Klaus

2018-03-30

Physical activity post stroke improves health, yet physical inactivity is highly prevalent. Tailored exercise programs considering physical activity preferences are a promising approach to promote physical activity. Therefore, this study seeks to measure exercise preferences of stroke survivors. Stroke survivors conducted a discrete choice experiment (DCE). DCE was presented in a face-to-face interview where patients had to choose eight times between two different exercise programs. Exercise programs differed by characteristics, with the six attributes under consideration being social situation, location, type of exercise, intensity, frequency, and duration. Utilities of the exercise attributes were estimated with a logit choice model. Stroke survivors (n=103, mean age: 67, SD=13.0; 60% male) show significant differences in the rated utilities of the exercise attributes (P<0.001). Participants had strong preferences for light and moderate intense physical activity and favored shorter exercise sessions. Stroke survivors have remarkable exercise preferences especially for intensity and duration of exercise. Results contribute to the tailoring of physical activity programs after stroke thereby facilitating maintenance of physical activity.

No Effect of Exercise Intensity on Appetite in Highly-Trained Endurance Women

PubMed Central

Howe, Stephanie M.; Hand, Taryn M.; Larson-Meyer, D. Enette; Austin, Kathleen J.; Alexander, Brenda M.; Manore, Melinda M.

2016-01-01

In endurance-trained men, an acute bout of exercise is shown to suppress post-exercise appetite, yet limited research has examined this response in women. The purpose of this study was to investigate the effect of exercise intensity on appetite and gut hormone responses in endurance-trained women. Highly-trained women (n = 15, 18–40 years, 58.4 ± 6.4 kg, VO2MAX = 55.2 ± 4.3 mL/kg/min) completed isocaloric bouts (500 kcals or 2093 kJ) of moderate-intensity (MIE, 60% VO2MAX) and high-intensity (HIE, 85% VO2MAX) treadmill running at the same time of day, following a similar 48-h diet/exercise period, and at least 1-week apart. Blood was drawn pre-exercise (baseline), immediately post-exercise and every 20-min for the next 60-min. Plasma concentrations of acylated ghrelin, PYY3–36, GLP-1 and subjective appetite ratings via visual analog scale (VAS) were assessed at each time point. Acylated ghrelin decreased (p = 0.014) and PYY3–36 and GLP-1 increased (p = 0.036, p < 0.0001) immediately post-exercise, indicating appetite suppression. VAS ratings of hunger and desire to eat decreased immediately post-exercise (p = 0.0012, p = 0.0031, respectively), also indicating appetite suppression. There were no differences between exercise intensities for appetite hormones or VAS. Similar to males, post-exercise appetite regulatory hormones were altered toward suppression in highly-trained women and independent of energy cost of exercise. Results are important for female athletes striving to optimize nutrition for endurance performance. PMID:27096869

Comparison of Methods for Determining Aerobic Exercise Intensity Using Heart Rate in Acute Leukemia Patients Prior to Induction Chemotherapy

PubMed Central

Story, Christina; Bryant, Ashley Leak; Phillips, Brett; Bailey, Charlotte; Shields, Edgar W.; Battaglini, Claudio

2018-01-01

Introduction Cardiopulmonary exercise testing (CPET), the gold standard of cardiopulmonary evaluation, is used to determine VO2 levels at different aerobic exercise training intensities; however, it may not be feasible to conduct CPET in all clinical settings. Aims To compare the heart rate reserve (HRR) and percent of 220-age methods for prescribing cycle ergometry exercise intensity using heart rate (HR) against the HRs obtained during a CPET in adults undergoing treatment for acute leukemia (AL). Methods In this exploratory study, part of a larger randomized controlled trial, 14 adults with AL completed CPET on a cycle ergometer with indirect calorimetry within 96 hr of admission to a cancer hospital to determine VO2peak and HR corresponding to low (40% VO2peak), moderate (60% VO2peak), and high (75% VO2peak) exercise intensities. Analyses of variance were used to compare estimated HR for each intensity level using the HRR and percent of 220-age methods with HR determined via VO2peak. Results HR corresponding to low-intensity exercise differed significantly across all three methods (p ≤ .05). No significant differences were observed between HR estimated via the percent of 220-age method and determined via VO2peak at moderate (100 ± 8 and 113 ± 24 bpm, p = .122) or high intensities (125 ± 10 and 123 ± 25 bpm, p = .994). Conclusion In adults with AL, HR-based methods for defining aerobic exercise intensities should be used with caution. At low intensity, neither should be used, while at moderate and high intensities, the percent of 220-age equation might serve as an adequate substitute for CPET. PMID:26933148

Mild peripheral neuropathy prevents both leg muscular ischaemia and activation of exercise-induced coagulation in Type 2 diabetic patients with peripheral artery disease.

PubMed

Piarulli, F; Sambataro, M; Minicuci, N; Scarano, L; Laverda, B; Baiocchi, M R; Baldo-Enzi, G; Galasso, S; Bax, G; Fedele, D

2007-10-01

To study the influence of peripheral neuropathy on intermittent claudication in patients with Type 2 diabetes (T2DM). Twenty-five patients with T2DM were grouped according to the ankle/brachial index (ABI): 10 with ABI > 0.9 without peripheral artery disease (PAD; group T2DM) and 15 with ABI < 0.9 with PAD (group T2DM + PAD). Twelve individuals without T2DM with PAD (group PAD without T2DM) were also enrolled. Tests for peripheral neuropathy were performed in all patients. ABI, rate pressure product, prothrombin fragments 1 + 2 (F1+2), thrombin-anti-thrombin complex (TAT), and d-dimer were measured before and after a treadmill test. During exercise both initial and absolute claudication distance and electrocardiogram readings were recorded. We found mild peripheral neuropathy in 20% of group T2DM and 46.7% of group T2DM + PAD (P < 0.01). After exercise, the rate pressure product increased in each group; ABI fell in T2DM + PAD (P < 0.0001) and in PAD without T2DM (P = 0.0005); the fall was greater in the latter group. Initial and absolute claudication distances were similar in PAD patients. In group T2DM + PAD, absolute claudication distance was longer in the subgroup without peripheral neuropathy (P < 0.05), whereas ABI and rate pressure products were similar. F1+2 values at rest were higher in group T2DM + PAD. After exercise, F1+2 values and TAT increased only in group PAD without T2DM. Only group PAD without T2DM experienced muscular ischaemia, whereas group T2DM + PAD did not. Mild peripheral neuropathy may have prevented them from reaching the point of muscular ischaemia during the treadmill test, because they stopped exercising with the early onset of pain. Reaching a false absolute claudication distance may induce ischaemic preconditioning. These findings suggest a possible protective role of mild peripheral neuropathy in T2DM patients with intermittent claudication, by preventing further activation of coagulation during treadmill testing.

Leisure time physical activity patterns in Odisha, India.

PubMed

Ganesh, G Shankar; Patel, Rishee; Dwivedi, Vikram; Chhabra, Deepak; Balakishore, P; Dakshinamoorthy, Anandhi; Kaur, Parminder

2018-05-01

The World Health Organization has recommended a moderate intensity physical activity of 150min, or 75min vigorous-intensity physical activity per week to achieve optimal health benefits. It is not known if Indian populations who indulge in leisure time physical exercises satisfy these recommendations. This study used a questionnaire to obtain data regarding demographic details, current engagement in leisure time physical activities, and dosages of these exercises from participants between 18 and 64 years of age. Data was collected from a total of 390 participants (231 males and 159 females). 50.76% and 34.35% of the participants reported exercising voluntarily and for health benefits respectively. Most participants (94.61%) indicated exercising without prescription. 55.38% and 12.82% of the participants under and above 38 years of age perform moderate to vigorous intensity exercises respectively. The over-all results of this study indicate that the participants' choices of leisure time physical exercises are based on their personal choices and beliefs. The exercise intensities undertaken do not meet the global recommended intensities, especially in those above 38 years of age. Professionals and facilities to engage the public in the WHO recommended intensities of physical activity needs to be established. Copyright © 2017 Diabetes India. Published by Elsevier Ltd. All rights reserved.

The differential effects of prolonged exercise upon executive function and cerebral oxygenation.

PubMed

Tempest, Gavin D; Davranche, Karen; Brisswalter, Jeanick; Perrey, Stephane; Radel, Rémi

2017-04-01

The acute-exercise effects upon cognitive functions are varied and dependent upon exercise duration and intensity, and the type of cognitive tasks assessed. The hypofrontality hypothesis assumes that prolonged exercise, at physiologically challenging intensities, is detrimental to executive functions due to cerebral perturbations (indicated by reduced prefrontal activity). The present study aimed to test this hypothesis by measuring oxygenation in prefrontal and motor regions using near-infrared spectroscopy during two executive tasks (flanker task and 2-back task) performed while cycling for 60min at a very low intensity and an intensity above the ventilatory threshold. Findings revealed that, compared to very low intensity, physiologically challenging exercise (i) shortened reaction time in the flanker task, (ii) impaired performance in the 2-back task, and (iii) initially increased oxygenation in prefrontal, but not motor regions, which then became stable in both regions over time. Therefore, during prolonged exercise, not only is the intensity of exercise assessed important, but also the nature of the cognitive processes involved in the task. In contrast to the hypofrontality hypothesis, no inverse pattern of oxygenation between prefrontal and motor regions was observed, and prefrontal oxygenation was maintained over time. The present results go against the hypofrontality hypothesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Physiological adaptations to interval training and the role of exercise intensity.

PubMed

MacInnis, Martin J; Gibala, Martin J

2017-05-01

Interval exercise typically involves repeated bouts of relatively intense exercise interspersed by short periods of recovery. A common classification scheme subdivides this method into high-intensity interval training (HIIT; 'near maximal' efforts) and sprint interval training (SIT; 'supramaximal' efforts). Both forms of interval training induce the classic physiological adaptations characteristic of moderate-intensity continuous training (MICT) such as increased aerobic capacity (V̇O2 max ) and mitochondrial content. This brief review considers the role of exercise intensity in mediating physiological adaptations to training, with a focus on the capacity for aerobic energy metabolism. With respect to skeletal muscle adaptations, cellular stress and the resultant metabolic signals for mitochondrial biogenesis depend largely on exercise intensity, with limited work suggesting that increases in mitochondrial content are superior after HIIT compared to MICT, at least when matched-work comparisons are made within the same individual. It is well established that SIT increases mitochondrial content to a similar extent to MICT despite a reduced exercise volume. At the whole-body level, V̇O2 max is generally increased more by HIIT than MICT for a given training volume, whereas SIT and MICT similarly improve V̇O2 max despite differences in training volume. There is less evidence available regarding the role of exercise intensity in mediating changes in skeletal muscle capillary density, maximum stroke volume and cardiac output, and blood volume. Furthermore, the interactions between intensity and duration and frequency have not been thoroughly explored. While interval training is clearly a potent stimulus for physiological remodelling in humans, the integrative response to this type of exercise warrants further attention, especially in comparison to traditional endurance training. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Physiological adaptations to interval training and the role of exercise intensity

PubMed Central

MacInnis, Martin J.

2016-01-01

Abstract Interval exercise typically involves repeated bouts of relatively intense exercise interspersed by short periods of recovery. A common classification scheme subdivides this method into high‐intensity interval training (HIIT; ‘near maximal’ efforts) and sprint interval training (SIT; ‘supramaximal’ efforts). Both forms of interval training induce the classic physiological adaptations characteristic of moderate‐intensity continuous training (MICT) such as increased aerobic capacity (V˙O2 max ) and mitochondrial content. This brief review considers the role of exercise intensity in mediating physiological adaptations to training, with a focus on the capacity for aerobic energy metabolism. With respect to skeletal muscle adaptations, cellular stress and the resultant metabolic signals for mitochondrial biogenesis depend largely on exercise intensity, with limited work suggesting that increases in mitochondrial content are superior after HIIT compared to MICT, at least when matched‐work comparisons are made within the same individual. It is well established that SIT increases mitochondrial content to a similar extent to MICT despite a reduced exercise volume. At the whole‐body level, V˙O2 max is generally increased more by HIIT than MICT for a given training volume, whereas SIT and MICT similarly improve V˙O2 max despite differences in training volume. There is less evidence available regarding the role of exercise intensity in mediating changes in skeletal muscle capillary density, maximum stroke volume and cardiac output, and blood volume. Furthermore, the interactions between intensity and duration and frequency have not been thoroughly explored. While interval training is clearly a potent stimulus for physiological remodelling in humans, the integrative response to this type of exercise warrants further attention, especially in comparison to traditional endurance training. PMID:27748956

Leisure-time exercise, physical activity during work and commuting, and risk of metabolic syndrome.

PubMed

Kuwahara, Keisuke; Honda, Toru; Nakagawa, Tohru; Yamamoto, Shuichiro; Akter, Shamima; Hayashi, Takeshi; Mizoue, Tetsuya

2016-09-01

Data are limited regarding effect of intensity of leisure-time physical activity on metabolic syndrome. Furthermore, no prospective data are available regarding effect of occupational and commuting physical activity on metabolic syndrome. We compared metabolic syndrome risk by intensity level of leisure-time exercise and by occupational and commuting physical activity in Japanese workers. We followed 22,383 participants, aged 30-64 years, without metabolic syndrome until 2014 March (maximum, 5 years of follow-up). Physical activity was self-reported. Metabolic syndrome was defined by the Joint Statement criteria. We used Cox regression models to estimate the hazard ratios (HRs) and 95 % confidence intervals (CIs) of metabolic syndrome. During a mean follow-up of 4.1 years, 5361 workers developed metabolic syndrome. After adjustment for covariates, compared with engaging in no exercise, the HRs (95 % CIs) for <7.5, 7.5 to <16.5, and ≥16.5 metabolic equivalent hours of exercise per week were 0.99 (0.90, 1.08), 0.99 (0.90, 1.10), and 0.95 (0.83, 1.08), respectively, among individuals engaging in moderate-intensity exercise alone; 0.93 (0.75, 1.14), 0.81 (0.64, 1.02), and 0.84 (0.66, 1.06), among individuals engaging in vigorous-intensity exercise alone; and 0.90 (0.70, 1.17), 0.74 (0.62, 0.89), and 0.81 (0.69, 0.96) among individuals engaging in the two intensities. Higher occupational physical activity was weakly but significantly associated with lower risk of metabolic syndrome. Walking to and from work was not associated with metabolic syndrome. Vigorous-intensity exercise alone or vigorous-intensity combined with moderate-intensity exercise and worksite intervention for physical activity may help prevent metabolic syndrome for Japanese workers.

Effects of exercise amount and intensity on abdominal obesity and glucose tolerance in obese adults: a randomized trial.

PubMed

Ross, Robert; Hudson, Robert; Stotz, Paula J; Lam, Miu

2015-03-03

Exercise reduces obesity and related glucose tolerance, but whether increasing exercise intensity offers additional benefit at fixed exercise amounts is unknown. To determine the separate effects of exercise amount and intensity on abdominal obesity and glucose tolerance. 24-week, single-center, parallel-group trial from 2009 to 2013. (ClinicalTrials.gov: NCT00955071). Kingston, Ontario, Canada. 300 abdominally obese adults. Control (no exercise) (n = 75) or 5 weekly sessions of low-amount, low-intensity exercise (LALI) (180 and 300 kcal/session for women and men, respectively, at 50% of maximum oxygen consumption [V̇o2peak]) (n = 73); high-amount, low-intensity exercise (HALI) (360 and 600 kcal/session, respectively, at 50% of V̇o2peak) (n = 76); or high-amount, high-intensity exercise (HAHI) (360 and 600 kcal/session, respectively, at 75% of V̇o2peak) (n = 76). Daily unsupervised physical activity and sedentary time were measured by accelerometer. Waist circumference and 2-hour glucose level (primary outcomes) and cardiorespiratory fitness and measures of insulin action (secondary measurements). 217 participants (72.3%) completed the intervention. Mean exercise time in minutes per session was 31 (SD, 4.4) for LALI, 58 (SD, 7.6) for HALI, and 40 (SD, 6.2) for HAHI. Daily unsupervised physical activity and sedentary time did not change in any exercise group versus control (P > 0.33). After adjustment for age and sex in a linear mixed model, reductions in waist circumference were greater in the LALI (-3.9 cm [95% CI, -5.6 to -2.3 cm]; P < 0.001), HALI (-4.6 cm [CI, -6.2 to -3.0 cm]; P < 0.001), and HAHI (-4.6 cm [CI, -6.3 to -2.9 cm]; P < 0.001) groups than the control group but did not differ among the exercise groups (P > 0.43). After adjustment for covariates, reductions in 2-hour glucose level were greater in the HAHI group (-0.7 mmol/L [-12.5 mg/dL] [CI, -1.3 to -0.1 mmol/L {-23.5 to -1.5 mg/dL}]; P = 0.027) than the control group but did not differ for the LALI or HALI group versus the control group (P > 0.159). Weight loss was greater in all exercise groups than the control group (P < 0.001); however, reduction in body weight did not differ among the exercise groups (P > 0.182). The clinical importance of reducing 2-hour glucose level in nondiabetic adults remains undetermined. Fixed amounts of exercise independent of exercise intensity resulted in similar reductions in abdominal obesity. Reduction in 2-hour glucose level was restricted to high-intensity exercise.

Respiratory weight losses during exercise.

NASA Technical Reports Server (NTRS)

Mitchell, J. W.; Nadel, E. R.; Stolwijk, J. A. J.

1972-01-01

Evaporative water loss from the respiratory tract was determined over a wide range of exercise. The absolute humidity of the expired air was the same at all levels of exercise and equal to that measured at rest. The rate of respiratory water loss during exercise was found to be 0.019 of the oxygen uptake times (44 minus water vapor pressure). The rate of weight loss during exercise due to CO2-O2 exchange was calculated. For exercise at oxygen consumption rates exceeding 1.5 L/min in a dry environment with a water vapor pressure of 10 mm Hg, the total rate of weight loss via the respiratory tract is on the order of 2-5 g/min.

The effect of exercise mode and intensity of sub-maximal physical activities on salivary testosterone to cortisol ratio and α-amylase in young active males

PubMed Central

AZARBAYJANI, MOHAMMAD ALI; FATOLAHI, HOSEYN; RASAEE, MOHAMMAD JAVAD; PEERI, MAGHSOD; BABAEI, ROHOLAH

2011-01-01

We examined the effect of exercise intensity and mode on the acute responses of free testosterone to cortisol ratio and salivary α-amylase. We also evaluated the relationship between cortisol and salivary α-amylase. Ten healthy young active males participated voluntarily in this study in six single sessions. They exercised on a cycle ergo meter, treadmill, and elliptical instrument at intensities of 70% and 85% maximum heart rate for 25 minutes. Saliva samples were collected 5 minutes before and 5 minutes after each exercise session. No significant changes were observed for cortisol. Free testosterone to cortisol ratio increased during each exercise session (F5, 45=3.15, P=0.02). However, these changes are only significant after exercise on the treadmill at 70% maximum heart rate (t=2.94, P=0.02) and 85% maximum heart rate (t=0.53, P=0.03). Salivary α-amylase significantly varied among exercise sessions (F5, 45=3.97, P=0.005), and a significant decline was observed after exercise on the elliptical instrument (t=2.38, P=0.04) and treadmill (t=3.55, P=0.006) at 85% maximum heart rate. We found that the free testosterone to cortisol ratio is dependent on the exercise mode, while the salivary α-amylase response is dependent on the intensity of exercise. The increase of free testosterone to cortisol ratio in this study may indicate lower physiological stress in response to performing these exercises. Applying muscular strength with moderate intensity weight-bearing exercises possibly activates the anabolic pathways. Although the cortisol and salivary α-amylase responses were opposite in the majority of the exercise sessions, no significant inverse relationship was observed. PMID:27182369

The effect of exercise mode and intensity of sub-maximal physical activities on salivary testosterone to cortisol ratio and α-amylase in young active males.

PubMed

Azarbayjani, Mohammad Ali; Fatolahi, Hoseyn; Rasaee, Mohammad Javad; Peeri, Maghsod; Babaei, Roholah

We examined the effect of exercise intensity and mode on the acute responses of free testosterone to cortisol ratio and salivary α-amylase. We also evaluated the relationship between cortisol and salivary α-amylase. Ten healthy young active males participated voluntarily in this study in six single sessions. They exercised on a cycle ergo meter, treadmill, and elliptical instrument at intensities of 70% and 85% maximum heart rate for 25 minutes. Saliva samples were collected 5 minutes before and 5 minutes after each exercise session. No significant changes were observed for cortisol. Free testosterone to cortisol ratio increased during each exercise session (F 5, 45 =3.15, P=0.02) . However, these changes are only significant after exercise on the treadmill at 70% maximum heart rate ( t=2.94, P=0.02 ) and 85% maximum heart rate ( t=0.53, P=0.03 ). Salivary α-amylase significantly varied among exercise sessions (F 5, 45 =3.97, P=0.005), and a significant decline was observed after exercise on the elliptical instrument (t=2.38, P=0.04) and treadmill ( t=3.55, P=0.006 ) at 85% maximum heart rate. We found that the free testosterone to cortisol ratio is dependent on the exercise mode, while the salivary α-amylase response is dependent on the intensity of exercise. The increase of free testosterone to cortisol ratio in this study may indicate lower physiological stress in response to performing these exercises. Applying muscular strength with moderate intensity weight-bearing exercises possibly activates the anabolic pathways. Although the cortisol and salivary α-amylase responses were opposite in the majority of the exercise sessions, no significant inverse relationship was observed.

Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions.

PubMed

Tsuruike, Masaaki; Ellenbecker, Todd

2014-11-14

Context :  Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. Objective :  To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Design :  Cross-sectional study. Setting :  Health Science Laboratory. Patients or Other Participants :  A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Main Outcome Measure(s) :  Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Results :  Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Conclusions :  Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited.

Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions

PubMed Central

Tsuruike, Masaaki; Ellenbecker, Todd S.

2015-01-01

Context: Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. Objective: To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Design: Cross-sectional study. Setting: Health Science Laboratory. Patients or Other Participants: A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Main Outcome Measure(s): Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Results: Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Conclusions: Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited. PMID:25689561

Anaerobic and Aerobic Performance of Elite Female and Male Snowboarders

PubMed Central

Żebrowska, Aleksandra; Żyła, Dorota; Kania, Damian; Langfort, Józef

2012-01-01

The physiological adaptation to training is specific to the muscle activity, dominant energy system involved, muscle groups trained, as well as intensity and volume of training. Despite increasing popularity of snowboarding only little scientific data is available on the physiological characteristics of female and male competitive snowboarders. Therefore, the purpose of this study was to compare the aerobic capacity and maximal anaerobic power of elite Polish snowboarders with untrained subjects. Ten snowboarders and ten aged matched students of Physical Education performed two exercise tests. First, a 30-second Wingate test was conducted and next, a cycle ergometer exercise test with graded intensity. In the first test, peak anaerobic power, the total work, relative peak power and relative mean power were measured. During the second test, relative maximal oxygen uptake and lactate threshold were evaluated. There were no significant differences in absolute and relative maximal oxygen uptake between snowboarders and the control group. Mean maximal oxygen uptake and lactate threshold were significantly higher in men than in women. Significant differences were found between trained men and women regarding maximal power and relative maximal power. The elite snowboarders demonstrated a high level of anaerobic power. The level of relative peak power in trained women correlated negatively with maximal oxygen uptake. In conclusion, our results seem to indicate that the demanding competition program of elite snowboarders provides a significant training stimulus mainly for anaerobic power with minor changes in anaerobic performance. PMID:23487498

Effect of exercise intensity on abdominal fat loss during calorie restriction in overweight and obese postmenopausal women: a randomized, controlled trial1234

PubMed Central

Nicklas, Barbara J; Wang, Xuewen; You, Tongjian; Lyles, Mary F; Demons, Jamehl; Easter, Linda; Berry, Michael J; Lenchik, Leon; Carr, J Jeffrey

2009-01-01

Background: Exercise intensity may affect the selective loss of abdominal adipose tissue. Objective: This study showed whether aerobic exercise intensity affects the loss of abdominal fat and improvement in cardiovascular disease risk factors under conditions of equal energy deficit in women with abdominal obesity. Design: This was a randomized trial in 112 overweight and obese [body mass index (in kg/m2): 25–40; waist circumference >88 cm], postmenopausal women assigned to one of three 20-wk interventions of equal energy deficit: calorie restriction (CR only), CR plus moderate-intensity aerobic exercise (CR + moderate-intensity), or CR plus vigorous-intensity exercise (CR + vigorous-intensity). The diet was a controlled program of underfeeding during which meals were provided at individual calorie levels (≈400 kcal/d). Exercise (3 d/wk) involved treadmill walking at an intensity of 45–50% (moderate-intensity) or 70–75% (vigorous-intensity) of heart rate reserve. The primary outcome was abdominal visceral fat volume. Results: Average weight loss for the 95 women who completed the study was 12.1 kg (±4.5 kg) and was not significantly different across groups. Maximal oxygen uptake (O2max) increased more in the CR + vigorous-intensity group than in either of the other groups (P < 0.05). The CR-only group lost relatively more lean mass than did either exercise group (P < 0.05). All groups showed similar decreases in abdominal visceral fat (≈25%; P < 0.001 for all). However, changes in visceral fat were inversely related to increases in O2max (P < 0.01). Changes in lipids, fasting glucose or insulin, and 2-h glucose and insulin areas during the oral-glucose-tolerance test were similar across treatment groups. Conclusion: With a similar amount of total weight loss, lean mass is preserved, but there is not a preferential loss of abdominal fat when either moderate- or vigorous-intensity aerobic exercise is performed during caloric restriction. This trial was registered at clinicaltrials.gov as NCT00664729. PMID:19211823

The effect of exercise mode on the acute response of satellite cells in old men.

PubMed

Nederveen, J P; Joanisse, S; Séguin, C M L; Bell, K E; Baker, S K; Phillips, S M; Parise, G

2015-12-01

A dysregulation of satellite cells may contribute to the progressive loss of muscle mass that occurs with age; however, older adults retain the ability to activate and expand their satellite cell pool in response to exercise. The modality of exercise capable of inducing the greatest acute response is unknown. We sought to characterize the acute satellite cell response following different modes of exercise in older adults. Sedentary older men (n = 22; 67 ± 4 years; 27 ± 2.6 kg*m(-2) ) were randomly assigned to complete an acute bout of either resistance exercise, high-intensity interval exercise on a cycle ergometer or moderate-intensity aerobic exercise. Muscle biopsies were obtained before, 24 and 48 h following each exercise bout. The satellite cell response was analysed using immunofluorescent microscopy of muscle cross sections. Satellite cell expansion associated with type I fibres was observed 24 and 48 h following resistance exercise only (P ˂ 0.05), while no expansion of type II-associated satellite cells was observed in any group. There was a greater number of activated satellite cells 24 h following resistance exercise (pre: 1.3 ± 0.1, 24 h: 4.8 ± 0.5 Pax7 + /MyoD+cells/100 fibres) and high-intensity interval exercise (pre: 0.7 ± 0.3, 24 h: 3.1 ± 0.3 Pax7 + /MyoD+cells/100 fibres) (P ˂ 0.05). The percentage of type I-associated SC co-expressing MSTN was reduced only in the RE group 24 h following exercise (pre: 87 ± 4, 24 h: 57 ± 5%MSTN+ type I SC) (P < 0.001). Although resistance exercise is the most potent exercise type to induce satellite cell pool expansion, high-intensity interval exercise was also more potent than moderate-intensity aerobic exercise in inducing satellite cell activity. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Influence of Skeletal Muscle Carnosine Content on Fatigue during Repeated Resistance Exercise in Recreationally Active Women

PubMed Central

Varanoske, Alyssa N.; Hoffman, Jay R.; Church, David D.; Baker, Kayla M.; Dodd, Sarah J.; Coker, Nicholas A.; Oliveira, Leonardo P.; Dawson, Virgil L.; Stout, Jeffrey R.

2017-01-01

Carnosine is a naturally occurring intramuscular dipeptide that is thought to attenuate fatigue during high-intensity exercise. Carnosine content is influenced by various factors, including gender and diet. Despite research reporting that carnosine content is lower in women compared to men and lower in vegetarians compared to omnivores, no investigations have examined carnosine content in women based on dietary protein intake and its effect on muscle fatigue. Twenty recreationally active women were assigned to either a high (HI; n = 5), moderate (MOD; n = 10), or low (LO; n = 5) group based upon intramuscular carnosine content of the vastus lateralis. Each participant underwent two unilateral maximal voluntary isometric contractions (MVIC) of the knee extensors separated by an isokinetic exercise protocol consisting of five sets of 50 repeated maximal unilateral contractions. Magnitude-based inferences were used to analyze group differences. Percent decline in rate of force development and peak torque (PT) during the MVICs and changes in PT and mean torque during the muscle-fatiguing protocol were lower in HI compared to both MOD and LO. Additionally, absolute and relative dietary protein intake were greater in HI compared to MOD or LO. Results indicated that greater intramuscular carnosine content was reflective of greater dietary protein intake and that individuals with higher carnosine content displayed a greater attenuation of fatigue compared to those with lower carnosine. PMID:28880219

Influence of Skeletal Muscle Carnosine Content on Fatigue during Repeated Resistance Exercise in Recreationally Active Women.

PubMed

Varanoske, Alyssa N; Hoffman, Jay R; Church, David D; Wang, Ran; Baker, Kayla M; Dodd, Sarah J; Coker, Nicholas A; Oliveira, Leonardo P; Dawson, Virgil L; Fukuda, David H; Stout, Jeffrey R

2017-09-07

Carnosine is a naturally occurring intramuscular dipeptide that is thought to attenuate fatigue during high-intensity exercise. Carnosine content is influenced by various factors, including gender and diet. Despite research reporting that carnosine content is lower in women compared to men and lower in vegetarians compared to omnivores, no investigations have examined carnosine content in women based on dietary protein intake and its effect on muscle fatigue. Twenty recreationally active women were assigned to either a high (HI; n = 5), moderate (MOD; n = 10), or low (LO; n = 5) group based upon intramuscular carnosine content of the vastus lateralis. Each participant underwent two unilateral maximal voluntary isometric contractions (MVIC) of the knee extensors separated by an isokinetic exercise protocol consisting of five sets of 50 repeated maximal unilateral contractions. Magnitude-based inferences were used to analyze group differences. Percent decline in rate of force development and peak torque (PT) during the MVICs and changes in PT and mean torque during the muscle-fatiguing protocol were lower in HI compared to both MOD and LO. Additionally, absolute and relative dietary protein intake were greater in HI compared to MOD or LO. Results indicated that greater intramuscular carnosine content was reflective of greater dietary protein intake and that individuals with higher carnosine content displayed a greater attenuation of fatigue compared to those with lower carnosine.

Variability in heart rate recovery measurements over 1 year in healthy, middle-aged adults.

PubMed

Mellis, M G; Ingle, L; Carroll, S

2014-02-01

This study assessed the longer-term (12-month) variability in post-exercise heart rate recovery following a submaximal exercise test. Longitudinal data was analysed for 97 healthy middle-aged adults (74 male, 23 female) from 2 occasions, 12 months apart. Participants were retrospectively selected if they had stable physical activity habits, submaximal treadmill fitness and anthropometric measurements between the 2 assessment visits. A submaximal Bruce treadmill test was performed to at least 85% age-predicted maximum heart rate. Absolute heart rate and Δ heart rate recovery (change from peak exercise heart rate) were recorded for 1 and 2 min post-exercise in an immediate supine position. Heart rate recovery at both time-points was shown to be reliable with intra-class correlation coefficient values ≥ 0.714. Absolute heart rate 1-min post-exercise showed the strongest agreement between repeat tests (r = 0.867, P < 0.001). Lower coefficient of variation (≤ 10.2%) and narrower limits of agreement were found for actual heart rate values rather than Δ heart rate recovery, and for 1-min rather than 2-min post-exercise recovery time points. Log-transformed values generated better variability with acceptable coefficient of variation for all measures (2.2-10%). Overall, 1 min post-exercise heart rate recovery data had least variability over the 12-month period in apparently healthy middle-aged adults. © Georg Thieme Verlag KG Stuttgart · New York.

High-intensity interval training using whole-body exercises: training recommendations and methodological overview.

PubMed

Machado, Alexandre F; Baker, Julien S; Figueira Junior, Aylton J; Bocalini, Danilo S

2017-05-04

HIIT whole body (HWB)-based exercise is a new calisthenics exercise programme approach that can be considered an effective and safe method to improve physical fitness and body composition. HWB is a method that can be applied to different populations and ages. The purpose of this study was to describe possible methodologies for performing physical training based on whole-body exercise in healthy subjects. The HWB sessions consist of a repeated stimulus based on high-intensity exercise that also include monitoring time to effort, time to recuperation and session time. The exercise intensity is related to the maximal number of movements possible in a given time; therefore, the exercise sessions can be characterized as maximal. The intensity can be recorded using ratings of perceived exertion. Weekly training frequency and exercise selection should be structured according to individual subject functional fitness. Using this simple method, there is potential for greater adherence to physical activity which can promote health benefits to all members of society. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

High- and low-intensity exercise do not improve cognitive function after stroke: A randomized controlled trial.

PubMed

Tang, Ada; Eng, Janice J; Krassioukov, Andrei V; Tsang, Teresa S M; Liu-Ambrose, Teresa

2016-11-11

To determine the effects of high versus low-intensity exercise on cognitive function following stroke. Secondary analysis from a randomized controlled trial with blinded assessors. 50-80 years old, living in the community, > 1 year post-stroke. Participants were randomized into a high-intensity Aerobic Exercise or low-intensity non-aerobic Balance/Flexibility program. Both programs were 6 months long, with 3 60-min sessions/week. Verbal item and working memory, selective attention and conflict resolution, set shifting were assessed before and after the program. Forty-seven participants completed the study (22/25 in Aerobic Exercise group, 25/25 in Balance/Flexibility group). There was an improvement in verbal item memory in both groups (time effect p = 0.04), and no between-group differences in improvement in the other outcomes (p > 0.27). There was no association between pre-exercise cognitive function and post-exercise improvement. In contrast to a small body of previous research suggesting positive benefits of exercise on cognition post-stroke, the current study found that 6 months of high or low intensity exercise was not effective in improving cognitive function, specifically executive functions. Further research in this area is warranted to establish the effectiveness of post-stroke exercise programs on cognition, and examine the mechanisms that underlie these changes.

Effect of exercise intensity on postprandial lipemia, markers of oxidative stress, and endothelial function after a high-fat meal.

PubMed

Lopes Krüger, Renata; Costa Teixeira, Bruno; Boufleur Farinha, Juliano; Cauduro Oliveira Macedo, Rodrigo; Pinto Boeno, Francesco; Rech, Anderson; Lopez, Pedro; Silveira Pinto, Ronei; Reischak-Oliveira, Alvaro

2016-12-01

The aim of this study was to compare the effects of 2 different exercise intensities on postprandial lipemia, oxidative stress markers, and endothelial function after a high-fat meal (HFM). Eleven young men completed 2-day trials in 3 conditions: rest, moderate-intensity exercise (MI-Exercise) and heavy-intensity exercise (HI-Exercise). Subjects performed an exercise bout or no exercise (Rest) on the evening of day 1. On the morning of day 2, an HFM was provided. Blood was sampled at fasting (0 h) and every hour from 1 to 5 h during the postprandial period for triacylglycerol (TAG), thiobarbituric acid reactive substance (TBARS), and nitrite/nitrate (NOx) concentrations. Flow-mediated dilatation (FMD) was also analyzed. TAG concentrations were reduced in exercise conditions compared with Rest during the postprandial period (P < 0.004). TAG incremental area under the curve (iAUC) was smaller after HI-Exercise compared with Rest (P = 0.012). TBARS concentrations were reduced in MI-Exercise compared with Rest (P < 0.041). FMD was higher in exercise conditions than Rest at 0 h (P < 0.02) and NOx concentrations were enhanced in MI-Exercise compared with Rest at 0 h (P < 0.01). These results suggest that acute exercise can reduce lipemia after an HFM. However, HI-Exercise showed to be more effective in reducing iAUC TAG, which might suggest higher protection against postprandial TAG enhancement. Conversely, MI-Exercise can be beneficial to attenuate the susceptibility of oxidative damage induced by an HFM and to increase endothelial function in the fasted state compared with Rest.

Prefrontal cortex haemodynamics and affective responses during exercise: a multi-channel near infrared spectroscopy study.

PubMed

Tempest, Gavin D; Eston, Roger G; Parfitt, Gaynor

2014-01-01

The dose-response effects of the intensity of exercise upon the potential regulation (through top-down processes) of affective (pleasure-displeasure) responses in the prefrontal cortex during an incremental exercise protocol have not been explored. This study examined the functional capacity of the prefrontal cortex (reflected by haemodynamics using near infrared spectroscopy) and affective responses during exercise at different intensities. Participants completed an incremental cycling exercise test to exhaustion. Changes (Δ) in oxygenation (O2Hb), deoxygenation (HHb), blood volume (tHb) and haemoglobin difference (HbDiff) were measured from bilateral dorsal and ventral prefrontal areas. Affective responses were measured every minute during exercise. Data were extracted at intensities standardised to: below ventilatory threshold, at ventilatory threshold, respiratory compensation point and the end of exercise. During exercise at intensities from ventilatory threshold to respiratory compensation point, ΔO2Hb, ΔHbDiff and ΔtHb were greater in mostly ventral than dorsal regions. From the respiratory compensation point to the end of exercise, ΔO2Hb remained stable and ΔHbDiff declined in dorsal regions. As the intensity increased above the ventilatory threshold, inverse associations between affective responses and oxygenation in (a) all regions of the left hemisphere and (b) lateral (dorsal and ventral) regions followed by the midline (ventral) region in the right hemisphere were observed. Differential activation patterns occur within the prefrontal cortex and are associated with affective responses during cycling exercise.

Prefrontal Cortex Haemodynamics and Affective Responses during Exercise: A Multi-Channel Near Infrared Spectroscopy Study

PubMed Central

Tempest, Gavin D.; Eston, Roger G.; Parfitt, Gaynor

2014-01-01

The dose-response effects of the intensity of exercise upon the potential regulation (through top-down processes) of affective (pleasure-displeasure) responses in the prefrontal cortex during an incremental exercise protocol have not been explored. This study examined the functional capacity of the prefrontal cortex (reflected by haemodynamics using near infrared spectroscopy) and affective responses during exercise at different intensities. Participants completed an incremental cycling exercise test to exhaustion. Changes (Δ) in oxygenation (O2Hb), deoxygenation (HHb), blood volume (tHb) and haemoglobin difference (HbDiff) were measured from bilateral dorsal and ventral prefrontal areas. Affective responses were measured every minute during exercise. Data were extracted at intensities standardised to: below ventilatory threshold, at ventilatory threshold, respiratory compensation point and the end of exercise. During exercise at intensities from ventilatory threshold to respiratory compensation point, ΔO2Hb, ΔHbDiff and ΔtHb were greater in mostly ventral than dorsal regions. From the respiratory compensation point to the end of exercise, ΔO2Hb remained stable and ΔHbDiff declined in dorsal regions. As the intensity increased above the ventilatory threshold, inverse associations between affective responses and oxygenation in (a) all regions of the left hemisphere and (b) lateral (dorsal and ventral) regions followed by the midline (ventral) region in the right hemisphere were observed. Differential activation patterns occur within the prefrontal cortex and are associated with affective responses during cycling exercise. PMID:24788166

Influence of Disease Severity and Exercise Limitation on Exercise Training Intensity and Load and Health Benefits From Pulmonary Rehabilitation in Patients with COPD: AN EXPLORATORY STUDY.

PubMed

Huynh, Virginia C; Fuhr, Desi P; Byers, Bradley W; Selzler, Anne-Marie; Moore, Linn E; Stickland, Michael K

2018-04-11

Some patients with chronic obstructive pulmonary disease (COPD) fail to achieve health benefits with pulmonary rehabilitation (PR). Exercise intensity and load represent stimulus for adaptation but it is unclear whether inappropriate exercise intensity and/or load are affected by severity of COPD, which may affect health benefits. The purpose was to determine whether COPD severity and/or the severity of pulmonary limitation to exercise (PLE) impacted exercising intensity or load and whether resultant intensity/load affected health outcomes derived from PR. Patients with COPD (n = 58, age = 67 ± 7 y, forced expiratory volume in the first second of expiration [FEV1] % predicted = 52 ± 21%) were recruited upon referral to PR. Primary health outcomes evaluated were 6-min walk distance and St George's Respiratory Questionnaire. Patients were stratified for disease severity using Global Initiative for Obstructive Lung Disease (GOLD) staging and PLE severity by change in inspiratory capacity during exercise. Exercise intensity and load were calculated from daily exercise records. Participants achieved comparable training duration and load regardless of GOLD severity. Patients with more severe PLE achieved greater training duration (more severe: 546 ± 143 min., less severe: 451 ± 109 min., P = .036), and relative training load (more severe: 2200.8 ± 595.3 kcal, less severe: 1648.3 ± 597.8 kcal, P = .007). Greater overall training load was associated with greater improvements in 6-min walk distance (r = 0.24, P = .035). No significant relationships were observed between PLE, GOLD severity, training parameters, and St George's Respiratory Questionnaire response. Improvements in exercise tolerance can be explained by achieving greater training loads, demonstrating the importance of appropriate training load to maximize health outcomes in PR.

Influence of exercise intensity on skeletal muscle blood flow, O2 extraction and O2 uptake on-kinetics

PubMed Central

Jones, Andrew M; Krustrup, Peter; Wilkerson, Daryl P; Berger, Nicolas J; Calbet, José A; Bangsbo, Jens

2012-01-01

Following the start of low-intensity exercise in healthy humans, it has been established that the kinetics of skeletal muscle O2 delivery is faster than, and does not limit, the kinetics of muscle O2 uptake (). Direct data are lacking, however, on the question of whether O2 delivery might limit kinetics during high-intensity exercise. Using multiple exercise transitions to enhance confidence in parameter estimation, we therefore investigated the kinetics of, and inter-relationships between, muscle blood flow (), a– difference and following the onset of low-intensity (LI) and high-intensity (HI) exercise. Seven healthy males completed four 6 min bouts of LI and four 6 min bouts of HI single-legged knee-extension exercise. Blood was frequently drawn from the femoral artery and vein during exercise and , a– difference and were calculated and subsequently modelled using non-linear regression techniques. For LI, the fundamental component mean response time (MRTp) for kinetics was significantly shorter than kinetics (mean ± SEM, 18 ± 4 vs. 30 ± 4 s; P < 0.05), whereas for HI, the MRTp for and was not significantly different (27 ± 5 vs. 29 ± 4 s, respectively). There was no difference in the MRTp for either or between the two exercise intensities; however, the MRTp for a– difference was significantly shorter for HI compared with LI (17 ± 3 vs. 28 ± 4 s; P < 0.05). Excess O2, i.e. oxygen not taken up (×), was significantly elevated within the first 5 s of exercise and remained unaltered thereafter, with no differences between LI and HI. These results indicate that bulk O2 delivery does not limit kinetics following the onset of LI or HI knee-extension exercise. PMID:22711961

Ergogenic effects of beetroot juice supplementation during severe-intensity exercise in obese adolescents.

PubMed

Rasica, Letizia; Porcelli, Simone; Marzorati, Mauro; Salvadego, Desy; Vezzoli, Alessandra; Agosti, Fiorenza; De Col, Alessandra; Tringali, Gabriella; Jones, Andrew M; Sartorio, Alessandro; Grassi, Bruno

2018-04-25

Previous studies showed a higher O 2 cost of exercise, and therefore a reduced exercise tolerance, in obese patients during constant work rate (CWR) exercise compared to healthy subjects. Among the ergogenic effects of dietary nitrate (NO 3 -) supplementation in sedentary healthy subjects, a reduced O 2 cost and enhanced exercise tolerance have often been demonstrated. The aim of this study was to evaluate the effects of beetroot juice supplementation, rich in NO 3 -, on physiological variables associated with exercise tolerance in obese adolescents. In a double-blind, randomized, crossover study, ten obese adolescents (8F, 2M; age=16{plus minus}1 yr; BMI=35.2{plus minus}5.0 kg.m -2 ) were tested after 6 days of supplementation with beetroot juice (5 mmol NO 3 - per day) (BR) or placebo (PLA). Following each supplementation period, patients carried out two repetitions of 6-min moderate-intensity CWR exercise and one severe-intensity CWR exercise until exhaustion. Plasma NO 3 - concentration was significantly higher in BR vs. PLA (108{plus minus}37 vs. 15{plus minus}5 μM, P<0.0001). The O 2 cost of moderate-intensity exercise was not different in BR vs. PLA (13.3{plus minus}1.7 vs. 12.9{plus minus}1.1 mL.min -1 .W -1 , P=0.517). During severe-intensity exercise, signs of a reduced amplitude of the O 2 uptake slow component were observed in BR, in association with a significantly longer time to exhaustion (561{plus minus}198 s in BR vs. 457{plus minus}101 s in PLA, P=0.0143). In obese adolescents, short-term dietary NO 3 - supplementation is effective in improving exercise tolerance during severe-intensity exercise. This may prove to be useful in contrasting early fatigue and reduced physical activity in this at-risk population.

Exercise Guidelines to Promote Cardiometabolic Health in Spinal Cord Injured Humans: Time to Raise the Intensity?

PubMed

Nightingale, Tom E; Metcalfe, Richard S; Vollaard, Niels B; Bilzon, James L

2017-08-01

Spinal cord injury (SCI) is a life-changing event that, as a result of paralysis, negatively influences habitual levels of physical activity and hence cardiometabolic health. Performing regular structured exercise therefore appears extremely important in persons with SCI. However, exercise options are mainly limited to the upper body, which involves a smaller activated muscle mass compared with the mainly leg-based activities commonly performed by nondisabled individuals. Current exercise guidelines for SCI focus predominantly on relative short durations of moderate-intensity aerobic upper-body exercise, yet contemporary evidence suggests this is not sufficient to induce meaningful improvements in risk factors for the prevention of cardiometabolic disease in this population. As such, these guidelines and their physiological basis require reappraisal. In this special communication, we propose that high-intensity interval training (HIIT) may be a viable alternative exercise strategy to promote vigorous-intensity exercise and prevent cardiometabolic disease in persons with SCI. Supplementing the limited data from SCI cohorts with consistent findings from studies in nondisabled populations, we present strong evidence to suggest that HIIT is superior to moderate-intensity aerobic exercise for improving cardiorespiratory fitness, insulin sensitivity, and vascular function. The potential application and safety of HIIT in this population is also discussed. We conclude that increasing exercise intensity could offer a simple, readily available, time-efficient solution to improve cardiometabolic health in persons with SCI. We call for high-quality randomized controlled trials to examine the efficacy and safety of HIIT in this population. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Effects of Different Intensities of Exercise on Intraocular Pressure

ERIC Educational Resources Information Center

Rowe, Deryl; And Others

1976-01-01

The decrease in intraocular pressure during exercise and the first few minutes of recovery is related to a decrease in blood pH and an increase in blood lactate concentration, not to the intensity of the exercise. (MB)

Randomized controlled trial of the effects of high intensity and low-to-moderate intensity exercise on physical fitness and fatigue in cancer survivors: results of the Resistance and Endurance exercise After ChemoTherapy (REACT) study.

PubMed

Kampshoff, Caroline S; Chinapaw, Mai J M; Brug, Johannes; Twisk, Jos W R; Schep, Goof; Nijziel, Marten R; van Mechelen, Willem; Buffart, Laurien M

2015-10-29

International evidence-based guidelines recommend physical exercise to form part of standard care for all cancer survivors. However, at present, the optimum exercise intensity is unclear. Therefore, we aimed to evaluate the effectiveness of a high intensity (HI) and low-to-moderate intensity (LMI) resistance and endurance exercise program compared with a wait list control (WLC) group on physical fitness and fatigue in a mixed group of cancer survivors who completed primary cancer treatment, including chemotherapy. Overall, 277 cancer survivors were randomized to 12 weeks of HI exercise (n = 91), LMI exercise (n = 95), or WLC (n = 91). Both interventions were identical with respect to exercise type, duration and frequency, and only differed in intensity. Measurements were performed at baseline (4-6 weeks after primary treatment) and post-intervention. The primary outcomes were cardiorespiratory fitness (peakVO2), muscle strength (grip strength and 30-second chair-stand test), and self-reported fatigue (Multidimensional Fatigue Inventory; MFI). Secondary outcomes included health-related quality of life, physical activity, daily functioning, body composition, mood, and sleep disturbances. Multilevel linear regression analyses were performed to estimate intervention effects using an intention-to-treat principle. In the HI and LMI groups, 74 % and 70 % of the participants attended more than 80 % of the prescribed exercise sessions, respectively (P = 0.53). HI (β = 2.2; 95 % CI, 1.2-3.1) and LMI (β = 1.3; 95 % CI, 0.3-2.3) exercise showed significantly larger improvements in peakVO2 compared to WLC. Improvements in peakVO2 were larger for HI than LMI exercise (β = 0.9; 95 % CI, -0.1 to 1.9), but the difference was not statistically significant (P = 0.08). No intervention effects were found for grip strength and the 30-second chair-stand test. HI and LMI exercise significantly reduced general and physical fatigue and reduced activity (MFI subscales) compared to WLC, with no significant differences between both interventions. Finally, compared to WLC, we found benefits in global quality of life and anxiety after HI exercise, improved physical functioning after HI and LMI exercise, and less problems at work after LMI exercise. Shortly after completion of cancer treatment, both HI and LMI exercise were safe and effective. There may be a dose-response relationship between exercise intensity and peakVO2, favoring HI exercise. HI and LMI exercise were equally effective in reducing general and physical fatigue. This study was registered at the Netherlands Trial Register [ NTR2153 ] on the 5th of January 2010.

The 'Critical Power' Concept: Applications to Sports Performance with a Focus on Intermittent High-Intensity Exercise.

PubMed

Jones, Andrew M; Vanhatalo, Anni

2017-03-01

The curvilinear relationship between power output and the time for which it can be sustained is a fundamental and well-known feature of high-intensity exercise performance. This relationship 'levels off' at a 'critical power' (CP) that separates power outputs that can be sustained with stable values of, for example, muscle phosphocreatine, blood lactate, and pulmonary oxygen uptake ([Formula: see text]), from power outputs where these variables change continuously with time until their respective minimum and maximum values are reached and exercise intolerance occurs. The amount of work that can be done during exercise above CP (the so-called W') is constant but may be utilized at different rates depending on the proximity of the exercise power output to CP. Traditionally, this two-parameter CP model has been employed to provide insights into physiological responses, fatigue mechanisms, and performance capacity during continuous constant power output exercise in discrete exercise intensity domains. However, many team sports (e.g., basketball, football, hockey, rugby) involve frequent changes in exercise intensity and, even in endurance sports (e.g., cycling, running), intensity may vary considerably with environmental/course conditions and pacing strategy. In recent years, the appeal of the CP concept has been broadened through its application to intermittent high-intensity exercise. With the assumptions that W' is utilized during work intervals above CP and reconstituted during recovery intervals below CP, it can be shown that performance during intermittent exercise is related to four factors: the intensity and duration of the work intervals and the intensity and duration of the recovery intervals. However, while the utilization of W' may be assumed to be linear, studies indicate that the reconstitution of W' may be curvilinear with kinetics that are highly variable between individuals. This has led to the development of a new CP model for intermittent exercise in which the balance of W' remaining ([Formula: see text]) may be calculated with greater accuracy. Field trials of athletes performing stochastic exercise indicate that this [Formula: see text] model can accurately predict the time at which W' tends to zero and exhaustion is imminent. The [Formula: see text] model potentially has important applications in the real-time monitoring of athlete fatigue progression in endurance and team sports, which may inform tactics and influence pacing strategy.

Energy-matched moderate and high intensity exercise training improves nonalcoholic fatty liver disease risk independent of changes in body mass or abdominal adiposity - A randomized trial.

PubMed

Winn, Nathan C; Liu, Ying; Rector, R Scott; Parks, Elizabeth J; Ibdah, Jamal A; Kanaley, Jill A

2018-01-01

Exercise training is commonly prescribed for individuals diagnosed with nonalcoholic fatty liver disease (NAFLD); however, consensus regarding the volume and intensity of exercise for optimal benefits is lacking. Thus, we determined whether high intensity interval exercise training (HIIT) produced greater reductions in intrahepatic lipid (IHL) content and NAFLD risk factors compared with energy-matched moderate intensity continuous exercise training (MICT) in obese adults with liver steatosis. Eighteen obese adults were randomized to either 4weeks of HIIT (4min 80% VO 2 peak/3min, 50% VO 2 peak) or MICT (55% VO 2 peak, ~60min), matched for energy expenditure (~400kcal/session) and compared to five non-exercising age-matched control subjects. IHL was measured by 1 H-MRS and frequent blood samples were analyzed for glucose, insulin, c-peptide, and NEFA levels during a liquid meal test (180min) to characterize metabolic phenotype. Baseline body weight, visceral abdominal adiposity, and fasting insulin concentrations were greater in the MICT vs HIIT group (P<0.05), while IHL was tightly matched between MICT and HIIT subjects (P>0.05), albeit higher than control subjects (P<0.01). Visceral abdominal adiposity, body mass, liver aminotransferases (ALT, AST), and hepatic apoptotic/inflammatory markers (cytokeratin 18 and fetuin a) were not reduced with either exercise training intervention (P>0.05). Both HIIT and MICT lowered IHL (HIIT, -37.0±12.4%; MICT, -20.1±6.6%, P<0.05); however, the reduction in IHL was not statistically different between exercise intensities (P=0.25). Furthermore, exercise training decreased postprandial insulin, c-peptide, and lipid peroxidation levels (iAUC, P<0.05). Collectively, these findings indicate that energy-matched high intensity and moderate intensity exercise are effective at decreasing IHL and NAFLD risk that is not contingent upon reductions in abdominal adiposity or body mass. Copyright © 2017 Elsevier Inc. All rights reserved.

Physiologic responses during indoor cycling.

PubMed

Battista, Rebecca A; Foster, Carl; Andrew, Jessica; Wright, Glenn; Lucia, Alejandro; Porcari, John P

2008-07-01

During the last decade, there has been active interest in indoor cycling (e.g., spinning) as a method of choreographed group exercise. Recent studies have suggested that exercise intensity during indoor cycling may be quite high and may transiently exceed Vo2max. This study sought to confirm these findings, as the apparent high intensity of indoor cycling has implications for both the efficacy and the risk of indoor cycling as an exercise method. Twenty healthy female students performed an incremental exercise test to define Vo2max and performed 2 videotaped indoor exercise classes lasting 45 minutes and 35 minutes. Vo2, heart rate (HR), and rating of perceived exertion (RPE) were measured during the indoor cycling classes, with Vo2 data integrated in 30-second intervals. The mean %Vo2max during the indoor cycling classes was modest (74 +/- 14% Vo2max and 66 +/- 14%Vo2max, respectively). However, 52% and 35% of the time during the 45- and 35-minute classes was spent at intensities greater than the ventilatory threshold (VT). The HR response indicated that 35% and 38% of the session time was above the HR associated with VT. In 10 of the 40 exercise sessions, there were segments in which the momentary Vo2 exceeded Vo2max observed during incremental testing, and the cumulative time with exercise intensity greater than Vo2max ranged from 0.5 to 14.0 minutes. It can be concluded that although the intensity of indoor cycling in healthy, physically active women is moderate, there are frequent observations of transient values of Vo2 exceeding Vo2max, and a substantial portion of the exercise bouts at intensities greater than VT. As such, the data suggest that indoor cycling must be considered a high-intensity exercise mode of exercise training, which has implications for both efficacy and risk.

High-intensity interval training without weight loss improves exercise but not basal or insulin-induced metabolism in overweight/obese African American women.

PubMed

Arad, Avigdor D; DiMenna, Fred J; Thomas, Naketa; Tamis-Holland, Jacqueline; Weil, Richard; Geliebter, Allan; Albu, Jeanine B

2015-08-15

The purpose of this randomized controlled clinical trial was to determine the effect of a 14-week high-intensity interval training (HIIT) intervention with weight stability on metabolic flexibility, insulin sensitivity, and cardiorespiratory fitness in sedentary, premenopausal, nondiabetic, overweight/obese African American women. Twenty-eight subjects were allocated to one of two groups: HIIT, which performed three sessions per week of four high-intensity cycling intervals, or a control group (CON), which maintained their normal level of physical activity. Diet was controlled for all subjects to ensure weight stability. Pre- and postintervention (pre/post), subjects completed an incremental cycling test to limit of tolerance and, following a 10-day high-fat controlled feeding period, a euglycemic-hyperinsulinemic clamp to determine insulin sensitivity and substrate oxidation. Nine members of HIIT (age, 29 ± 4 yr; body mass, 90.1 ± 13.8 kg) and eleven members of CON (age, 30 ± 7 yr; body mass, 85.5 ± 10.7 kg) completed the study. HIIT experienced an increased limit of tolerance (post, 1,124 ± 202 s; pre, 987 ± 146 s; P < 0.05), gas exchange threshold (post, 1.29 ± 0.34 liters/min; pre, 0.97 ± 0.23 liters/min; P < 0.05), and fat oxidation at the same absolute submaximal work rate compared with CON (P < 0.05 for group-by-time interaction in all cases). However, changes in peak oxygen consumption (V̇o2peak), insulin sensitivity, free fatty acid suppression during insulin stimulation, and metabolic flexibility were not different in HIIT compared with CON. High-intensity interval training with weight stability increased exercise fat oxidation and tolerance in subjects at risk for diabetic progression, but did not improve insulin sensitivity or fat oxidation in the postabsorptive or insulin-stimulated state. Copyright © 2015 the American Physiological Society.

The Effect of High Intensity Interval Run Training on Cross-sectional Area of the Vastus Lateralis in Untrained College Students

PubMed Central

ESTES, REBEKAH R.; MALINOWSKI, AMY; PIACENTINI, MEREDITH; THRUSH, DAVID; SALLEY, ERIC; LOSEY, CASSIDY; HAYES, ERIK

2017-01-01

Aerobic cycling has been repeatedly shown to induce hypertrophy in skeletal muscle across a variety of populations, while there has been a lack of investigation into the impact of running upon hypertrophy. An increasingly popular model of aerobic exercise is high-intensity interval training (HIIT); in addition to its positive impact upon cardiovascular health, HIIT may be sufficient for inducing significant muscular hypertrophy. Therefore, the purpose of this investigation was to examine the influence of a high-intensity interval running protocol upon hypertrophy of the vastus lateralis in an untrained, young population. Twelve recreationally active university students (Male: 2; Female: 10; 19.9±0.5 yr.; 169.8±1.9 cm; 63.8±2.3 kg; VO2max: 42.1±1.6 ml•kg−1min−1) completed 24.5±0.6 sessions of high-intensity interval run training over 10 weeks. The protocol consisted of four sets of 4 minutes running at 90–95% HRmax followed by 3 minutes active rest at 70% HRmax. Relative and absolute aerobic capacity increased 5.2±2.2% and 6.0±2.3% respectively as a result of the intervention (p< 0.05). Cross-sectional area (CSA) of the vastus lateralis was measured via panoramic ultrasound imaging pre- and post-intervention. Following the protocol, CSA of the intervention group was 10.6±2.7% greater (p< 0.05), while that of the control group did not change. This is the first data to demonstrate hypertrophy of the vastus lateralis in a young population following a running protocol. These data support the existing body of evidence suggesting aerobic exercise to be an effective mode of improving cardiorespiratory fitness as well as increasing whole muscle size of the quadriceps. PMID:28479954

Influence of Upper-Body Exercise on the Fatigability of Human Respiratory Muscles

PubMed Central

TILLER, NICHOLAS B.; CAMPBELL, IAN G.; ROMER, LEE M.

2017-01-01

ABSTRACT Purpose Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. Methods Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O2 uptake [V˙O2peak] = 31.9 ± 5.3 mL·kg−1·min−1) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O2peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to postexercise changes in potentiated transdiaphragmatic and gastric twitch pressures (Pdi,tw and Pga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively. Results Exercise time was 24.5 ± 5.8 min for heavy exercise and 9.8 ± 1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73 ± 20 L·min−1 (39% ± 11% maximum voluntary ventilation) and 99 ± 19 L·min−1 (53% ± 11% maximum voluntary ventilation) for severe exercise. Mean Pdi,tw did not differ pre- to postexercise at either intensity (P > 0.05). Immediately (5–15 min) after severe exercise, mean Pga,tw was significantly lower than pre-exercise values (41 ± 13 vs 53 ± 15 cm H2O, P < 0.05), with the difference no longer significant after 25–35 min. Abdominal muscle fatigue (defined as ≥15% reduction in Pga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise. Conclusions High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (nonrespiratory) loading of the thorax. PMID:28288012

Influence of Upper-Body Exercise on the Fatigability of Human Respiratory Muscles.

PubMed

Tiller, Nicholas B; Campbell, Ian G; Romer, Lee M

2017-07-01

Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O2 uptake [V˙O2peak] = 31.9 ± 5.3 mL·kg·min) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O2peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to postexercise changes in potentiated transdiaphragmatic and gastric twitch pressures (Pdi,tw and Pga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively. Exercise time was 24.5 ± 5.8 min for heavy exercise and 9.8 ± 1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73 ± 20 L·min (39% ± 11% maximum voluntary ventilation) and 99 ± 19 L·min (53% ± 11% maximum voluntary ventilation) for severe exercise. Mean Pdi,tw did not differ pre- to postexercise at either intensity (P > 0.05). Immediately (5-15 min) after severe exercise, mean Pga,tw was significantly lower than pre-exercise values (41 ± 13 vs 53 ± 15 cm H2O, P < 0.05), with the difference no longer significant after 25-35 min. Abdominal muscle fatigue (defined as ≥15% reduction in Pga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise. High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (nonrespiratory) loading of the thorax.

Aerobic Exercise Training in Post-Polio Syndrome: Process Evaluation of a Randomized Controlled Trial.

PubMed

Voorn, Eric L; Koopman, Fieke S; Brehm, Merel A; Beelen, Anita; de Haan, Arnold; Gerrits, Karin H L; Nollet, Frans

2016-01-01

To explore reasons for the lack of efficacy of a high intensity aerobic exercise program in post-polio syndrome (PPS) on cardiorespiratory fitness by evaluating adherence to the training program and effects on muscle function. A process evaluation using data from an RCT. Forty-four severely fatigued individuals with PPS were randomized to exercise therapy (n = 22) or usual care (n = 22). Participants in the exercise group were instructed to exercise 3 times weekly for 4 months on a bicycle ergometer (60-70% heart rate reserve). The attendance rate was high (median 89%). None of the participants trained within the target heart rate range during >75% of the designated time. Instead, participants exercised at lower intensities, though still around the anaerobic threshold (AT) most of the time. Muscle function did not improve in the exercise group. Our results suggest that severely fatigued individuals with PPS cannot adhere to a high intensity aerobic exercise program on a cycle ergometer. Despite exercise intensities around the AT, lower extremity muscle function nor cardiorespiratory fitness improved. Improving the aerobic capacity in PPS is difficult through exercise primarily focusing on the lower extremities, and may require a more individualized approach, including the use of other large muscle groups instead. Netherlands National Trial Register NTR1371.

Importance of characteristics and modalities of physical activity and exercise in the management of cardiovascular health in individuals with cardiovascular disease (Part III).

PubMed

Vanhees, L; Rauch, B; Piepoli, M; van Buuren, F; Takken, T; Börjesson, M; Bjarnason-Wehrens, B; Doherty, P; Dugmore, D; Halle, M

2012-12-01

The beneficial effect of exercise training and exercise-based cardiac rehabilitation on symptom-free exercise capacity,cardiovascular and skeletal muscle function, quality of life, general healthy lifestyle, and reduction of depressive symptoms and psychosocial stress is nowadays well recognized. However, it remains largely obscure, which characteristics of physical activity (PA) and exercise training--frequency, intensity, time (duration), type (mode), and volume (dose: intensity x duration) of exercise--are the most effective. The present paper, therefore, will deal with these exercise characteristics in the management of individuals with cardiovascular disease, i.e. coronary artery disease and chronic heart failure patients, but also in patients with congenital or valvular heart disease. Based on the current literature, and if sufficient evidence is available, recommendations from the European Association on Cardiovascular Prevention and Rehabilitation are formulated regarding frequency, intensity, time and type of PA, and safety aspects during exercise inpatients with cardiovascular disease. This paper is the third in a series of three papers, all devoted to the same theme: the importance of the exercise characteristics in the management of cardiovascular health. Part I is directed to the general population and Part II to individuals with cardiovascular risk factors. In general, PA recommendations and exercise training programmes for patients with coronary artery disease or chronic heart failure need to be tailored to the individual's exercise capacity and risk profile, with the aim to reach and maintain the individually highest fitness level possible and to perform endurance exercise training 30–60 min daily (3–5 days per week) in combination with resistance training 2–3 times a week. Because of the frequently reported dose–response relationship between training effect and exercise intensity, one should seek sufficiently high training intensities, although more scientific evidence on effect sizes and safety is warranted. At present, there is insufficient data to give more specific recommendations on type, dosage, and intensity of exercise in some other cardiovascular diseases, such as congenital heart disease, valve disease, cardiomyopathies, channelopathies, and patients with implanted devices.

The Effect of a 20 km Run on Appetite Regulation in Long Distance Runners

PubMed Central

Kojima, Chihiro; Ishibashi, Aya; Ebi, Kumiko; Goto, Kazushige

2016-01-01

The purpose of the present study was to investigate appetite-related hormonal responses and energy intake after a 20 km run in trained long distance runners. Twenty-three male long-distance runners completed two trials: either an exercise trial consisting of a 20 km outdoor run (EX) or a control trial with an identical period of rest (CON). Blood samples were collected to determine plasma acylated ghrelin, peptide YY3-36 (PYY3-36) and other hormonal and metabolite concentrations. Energy intake during a buffet test meal was also measured 30 min after the exercise or rest periods. Although plasma acylated ghrelin concentrations were significantly decreased after the 20 km run (p < 0.05), plasma PYY3-36 did not change significantly following exercise. Absolute energy intake during the buffet test meal in EX (1325 ± 55 kcal) was significantly lower than that in CON (1529 ± 55 kcal), and there was a relatively large degree of individual variability for exercise-induced changes in energy intake (−40.2% to 12.8%). However, exercise-induced changes in energy intake were not associated with plasma acylated ghrelin or PYY3-36 responses. The results demonstrated that a 20 km run significantly decreased plasma acylated ghrelin concentrations and absolute energy intake among well-trained long distance runners. PMID:27792164

Effects of exercise on craving and cigarette smoking in the human laboratory.

PubMed

Kurti, Allison N; Dallery, Jesse

2014-06-01

Exercise is increasingly being pursued as a treatment to reduce cigarette smoking. The efficacy of clinical, exercise-based cessation interventions may be enhanced by conducting laboratory studies to determine maximally effective conditions for reducing smoking, and the mechanisms through which the effects on smoking are achieved. The main purpose of this study was to assess whether the effects of exercise on two components of craving (anticipated reward from smoking, anticipated relief from withdrawal) mediated the relationship between exercise and delay (in min) to ad libitum smoking. Experiment 1 (N=21) assessed the effects of exercise intensity (inactivity, low, moderate) on craving components up to 60 min post-exercise. Because moderate-intensity exercise most effectively reduced craving on the reward component, all participants exercised at a moderate intensity in Experiment 2. Using an ABAB within-subjects design, Experiment 2 (N=20) evaluated whether the effects of moderate-intensity exercise on reward and relief components of craving mediated the relationship between exercise and participants' delays (in min) to ad libitum smoking. Delays were significantly longer after exercise (M=21 min) versus inactivity (M=4 min), and the effects of exercise on delay were mediated through the reward component of craving. Future research should continue to explore the mechanisms through which exercise influences behavioral indices of smoking in the human laboratory. Additionally, given the benefits uniquely afforded by exercise-based cessation interventions (e.g., improving mood and other health outcomes), implementing these interventions in clinical settings may contribute substantially to improving public health. Copyright © 2014 Elsevier Ltd. All rights reserved.

Increased atrial arrhythmia susceptibility induced by intense endurance exercise in mice requires TNFα

PubMed Central

Aschar-Sobbi, Roozbeh; Izaddoustdar, Farzad; Korogyi, Adam S.; Wang, Qiongling; Farman, Gerrie P.; Yang, FengHua; Yang, Wallace; Dorian, David; Simpson, Jeremy A.; Tuomi, Jari M.; Jones, Douglas L.; Nanthakumar, Kumaraswamy; Cox, Brian; Wehrens, Xander H.T.; Dorian, Paul; Backx, Peter H.

2015-01-01

Atrial fibrillation (AF) is the most common supraventricular arrhythmia that, for unknown reasons, is linked to intense endurance exercise. Our studies reveal that 6 weeks of swimming or treadmill exercise improves heart pump function and reduces heart-rates. Exercise also increases vulnerability to AF in association with inflammation, fibrosis, increased vagal tone, slowed conduction velocity, prolonged cardiomyocyte action potentials and RyR2 phosphorylation (CamKII-dependent S2814) in the atria, without corresponding alterations in the ventricles. Microarray results suggest the involvement of the inflammatory cytokine, TNFα, in exercised-induced atrial remodelling. Accordingly, exercise induces TNFα-dependent activation of both NFκB and p38MAPK, while TNFα inhibition (with etanercept), TNFα gene ablation, or p38 inhibition, prevents atrial structural remodelling and AF vulnerability in response to exercise, without affecting the beneficial physiological changes. Our results identify TNFα as a key factor in the pathology of intense exercise-induced AF. PMID:25598495

Exercise Effects on Fitness and Bone Mineral Density in Early Postmenopausal Women: 1-Year EFOPS Results.

ERIC Educational Resources Information Center

Kemmler, Wolfgang; Engelke, Klaus; Lauber, Dirk; Weineck, Juergen; Hensen, Johannes; Kalender, Willi A.

2002-01-01

Investigated the effect of intense exercise training on physical fitness, coronary heart disease, bone mineral density (BMD), and parameters related to quality of life in early postmenopausal women with osteopenia. Data on woman in control and exercise training groups indicated that the intense exercise training program was effective in improving…

Absolute laser-intensity measurement and online monitor calibration using a calorimeter at a soft X-ray free-electron laser beamline in SACLA

NASA Astrophysics Data System (ADS)

Tanaka, Takahiro; Kato, Masahiro; Saito, Norio; Owada, Shigeki; Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya

2018-06-01

This paper reports measurement of the absolute intensity of free-electron laser (FEL) and calibration of online intensity monitors for a brand-new FEL beamline BL1 at SPring-8 Angstrom Compact free-electron LAser (SACLA) in Japan. To measure the absolute intensity of FEL, we used a room-temperature calorimeter originally developed for FELs in the hard X-ray range. By using the calorimeter, we calibrated online intensity monitors of BL1, gas monitors (GMs), based on the photoionization of argon gas, in the photon energy range from 25 eV to 150 eV. A good correlation between signals obtained from the calorimeter and GMs was observed in the pulse energy range from 1 μJ to 100 μJ, where the upper limit is nearly equal to the maximum pulse energy at BL1. Moreover, the calibration result of the GMs, measured in terms of the spectral responsivity, demonstrates a characteristic photon-energy dependence owing to the occurrence of the Cooper minimum in the total ionization cross-section of argon gas. These results validate the feasibility of employing the room-temperature calorimeter in the measurement of absolute intensity of FELs over the specified photon energy range.

Muscle metabolic and neuromuscular determinants of fatigue during cycling in different exercise intensity domains

PubMed Central

Black, Matthew I.; Jones, Andrew M.; Blackwell, Jamie R.; Bailey, Stephen J.; Wylie, Lee J.; McDonagh, Sinead T. J.; Thompson, Christopher; Kelly, James; Sumners, Paul; Mileva, Katya N.; Bowtell, Joanna L.

2017-01-01

Lactate or gas exchange threshold (GET) and critical power (CP) are closely associated with human exercise performance. We tested the hypothesis that the limit of tolerance (Tlim) during cycle exercise performed within the exercise intensity domains demarcated by GET and CP is linked to discrete muscle metabolic and neuromuscular responses. Eleven men performed a ramp incremental exercise test, 4–5 severe-intensity (SEV; >CP) constant-work-rate (CWR) tests until Tlim, a heavy-intensity (HVY; GET) CWR test until Tlim, and a moderate-intensity (MOD; 0.05) muscle metabolic milieu (i.e., low pH and [PCr] and high [lactate]) was attained at Tlim (approximately 2–14 min) for all SEV exercise bouts. The muscle metabolic perturbation was greater at Tlim following SEV compared with HVY, and also following SEV and HVY compared with MOD (all P < 0.05). The normalized M-wave amplitude for the vastus lateralis (VL) muscle decreased to a similar extent following SEV (−38 ± 15%), HVY (−68 ± 24%), and MOD (−53 ± 29%), (P > 0.05). Neural drive to the VL increased during SEV (4 ± 4%; P < 0.05) but did not change during HVY or MOD (P > 0.05). During SEV and HVY, but not MOD, the rates of change in M-wave amplitude and neural drive were correlated with changes in muscle metabolic ([PCr], [lactate]) and blood ionic/acid-base status ([lactate], [K+]) (P < 0.05). The results of this study indicate that the metabolic and neuromuscular determinants of fatigue development differ according to the intensity domain in which the exercise is performed. NEW & NOTEWORTHY The gas exchange threshold and the critical power demarcate discrete exercise intensity domains. For the first time, we show that the limit of tolerance during whole-body exercise within these domains is characterized by distinct metabolic and neuromuscular responses. Fatigue development during exercise greater than critical power is associated with the attainment of consistent “limiting” values of muscle metabolites, whereas substrate availability and limitations to muscle activation may constrain performance at lower intensities. PMID:28008101

Effects of exercise on the desire to smoke and physiological responses to temporary smoking abstinence: a crossover trial.

PubMed

Roberts, Vaughan; Gant, Nicholas; Sollers, John J; Bullen, Chris; Jiang, Yannan; Maddison, Ralph

2015-03-01

Exercise has been shown to attenuate cigarette cravings during temporary smoking abstinence; however, the mechanisms of action are not clearly understood. The objectives of the study were to compare the effects of three exercise intensities on desire to smoke and explore potential neurobiological mediators of desire to smoke. Following overnight abstinence, 40 participants (25 males, 18-59 years) completed three 15 min sessions of light-, moderate-, or vigorous-intensity exercise on a cycle ergometer in a randomized crossover design. Ratings of desire to smoke were self-reported pre- and post-exercise and heart rate variability was measured throughout. Saliva and blood were analyzed for cortisol and noradrenaline in a sub-sample. Exercise influenced desire to smoke (F [2, 91] = 7.94, p < 0.01), with reductions greatest immediately after vigorous exercise. There were also significant time x exercise intensity interaction effects for heart rate variability and plasma noradrenaline (F [8, 72] = 2.23, p = 0.03), with a bias in noradrenaline occurring between light and vigorous conditions (adjusted mean difference [SE] = 2850 ng/ml [592], p < 0.01) at 5 min post-exercise. There was no interaction of time x exercise intensity for plasma and salivary cortisol levels. These findings support the use of vigorous exercise to reduce cigarette cravings, showing potential alterations in a noradrenergic marker.

Irisin in response to exercise in humans with and without metabolic syndrome.

PubMed

Huh, Joo Young; Siopi, Aikaterina; Mougios, Vassilis; Park, Kyung Hee; Mantzoros, Christos S

2015-03-01

Irisin is a recently identified exercise-induced myokine. However, the circulating levels of irisin in response to different types of exercise in subjects with metabolic syndrome are unknown. This study aimed to study the levels of irisin in healthy males and subjects with metabolic syndrome at baseline and in response to exercise. Each individual completed high-intensity interval exercise (HIIE), continuous moderate-intensity exercise (CME), and resistance exercise (RE) sessions in a random, crossover design. Percentage change in circulating irisin levels was examined. Two different irisin assays were used to compare the results of the RE study. Circulating irisin increased immediately after HIIE, CME, and RE and declined 1 hour later. The increase was greater in response to resistance compared with either high-intensity intermittent exercise or CME. Change in irisin in response to exercise did not differ between individuals with and without metabolic syndrome. Exercise is able to increase circulating irisin levels in individuals with the metabolic syndrome as well as healthy individuals. Whether this increase may contribute to the beneficial effects of exercise on patients with the metabolic syndrome remains to be studied further.

Effects of Exercise Intervention on Preventing Letrozole-Exposed Rats From Polycystic Ovary Syndrome.

PubMed

Cao, Si-Fan; Hu, Wen-Long; Wu, Min-Min; Jiang, Li-Yan

2017-03-01

Polycystic ovary syndrome (PCOS) is a prevalent endocrinological disorder in reproductive-age women and is often associated with a metabolic syndrome. To investigate whether exercise intervention promotes PCOS prevention, a rat model was used. Polycystic ovary syndrome was induced by letrozole administration, and animals presented with obesity, sex hormone disorder, no ovulation, large cystic follicles, and increasing fasting insulin (FINS) and leptin levels. The intervention was set at 3 different intensities of swimming exercise: low (0.5 h/d), moderate (1 h/d), and high (2 h/d), and compared with a PCOS model group (letrozole administration without exercise intervention) and a control group. The exercise intervention in the low-intensity group did not produce changes in obesity, testosterone, progesterone (P), and follicle-stimulating hormone (FSH) levels. Moderate-intensity exercise reduced body weight, retained ovulation, and P levels were increased but remained lower than those in the control group. The FSH levels were significantly higher, and FINS and leptin levels were lower than in the model group ( P < 0.05) but not in the control group. The high-intensity group demonstrated the greatest effect of PCOS prevention. Testosterone, luteinizing hormone, FINS, and leptin levels were significantly lower in the high-intensity group, and FSH and P levels were higher compared with the model group. These results suggest that high-intensity exercise intervention can effectively prevent PCOS development.

Effects of Warm-Up and Fatigue on Knee Joint Position Sense and Jump Performance.

PubMed

Romero-Franco, N; Jiménez-Reyes, P

2017-01-01

The purpose of this study was to evaluate the effects of a warm-up and fatigue protocol on the vertical jump and knee joint position sense of sprinters. Thirty-two sprinters were randomly allocated to either a control group (CONT) or a plyometric group (PLYO) that performed a warm-up, followed by a high-intensity plyometric protocol. Absolute (AAE), relative (RAE), and variable (VAE) angular errors and vertical jump were evaluated before and after the warm-up, as well as after the plyometric protocol and again 5 min later. After the warm-up, athletes improved RAE and jump performance. After the plyometric protocol, scores on the RAE, VAE, and the vertical jump performance worsened compared to the control group and to the values obtained after the warm-up. Five minutes later, RAE and vertical jump continued to be impaired. AAE did not show significant differences. The vertical jump is improved after the warm-up, although it is deteriorated after high-intensity plyometry. Regarding knee proprioception, the lack of impairments in the AAE make unclear the effects of the plyometric exercises on knee proprioception.

Differences in the Intensity and Duration of Adolescents' Sports and Exercise across Physical and Social Environments

ERIC Educational Resources Information Center

Dunton, Genevieve Fridlund; Berrigan, David; Ballard-Barbash, Rachel; Perna, Frank; Graubard, Barry I.; Atienza, Audie A.

2012-01-01

We used data from the American Time Use Survey (years 2003-06) to analyze whether the intensity and duration of high school students' (ages 15-18 years) sports and exercise bouts differed across physical and social environments. Boys' sports and exercise bouts were more likely to reach a vigorous intensity when taking place at school and with…

Within-session responses to high-intensity interval training in spinal cord injury.

PubMed

Astorino, Todd Anthony; Thum, Jacob S

2018-02-01

Completion of high-intensity interval training (HIIT) increases maximal oxygen uptake and health status, yet its feasibility in persons with spinal cord injury is unknown. To compare changes in cardiorespiratory and metabolic variables between two interval training regimes and moderate intensity exercise. Nine adults with spinal cord injury (duration = 6.8 ± 6.2 year) initially underwent determination of peak oxygen uptake. During subsequent sessions, they completed moderate intensity exercise, HIIT, or sprint interval training. Oxygen uptake, heart rate, and blood lactate concentration were measured. Oxygen uptake and heart rate increased (p < 0.05) during both interval training sessions and were similar (p > 0.05) to moderate intensity exercise. Peak oxygen uptake and heart rate were higher (p < 0.05) with HIIT (90% peak oxygen uptake and 99% peak heart rate) and sprint interval training (80% peak oxygen uptake and 96% peak heart rate) versus moderate intensity exercise. Despite a higher intensity and peak cardiorespiratory strain, all participants preferred interval training versus moderate exercise. Examining long-term efficacy and feasibility of interval training in this population is merited, considering that exercise intensity is recognized as the most important variable factor of exercise programming to optimize maximal oxygen uptake. Implications for Rehabilitation Spinal cord injury (SCI) reduces locomotion which impairs voluntary physical activity, typically resulting in a reduction in peak oxygen uptake and enhanced chronic disease risk. In various able-bodied populations, completion of high-intensity interval training (HIIT) has been consistently reported to improve cardiorespiratory fitness and other health-related outcomes, although its efficacy in persons with SCI is poorly understood. Data from this study in 9 men and women with SCI show similar changes in oxygen uptake and heart in response to HIIT compared to a prolonged bout of aerobic exercise, although peak values were higher in response to HIIT. Due to the higher peak metabolic strain induced by HIIT as well as universal preference for this modality versus aerobic exercise as reported in this study, further work testing utility of HIIT in this population is merited.

High Intensity Interval Training for Maximizing Health Outcomes.

PubMed

Karlsen, Trine; Aamot, Inger-Lise; Haykowsky, Mark; Rognmo, Øivind

Regular physical activity and exercise training are important actions to improve cardiorespiratory fitness and maintain health throughout life. There is solid evidence that exercise is an effective preventative strategy against at least 25 medical conditions, including cardiovascular disease, stroke, hypertension, colon and breast cancer, and type 2 diabetes. Traditionally, endurance exercise training (ET) to improve health related outcomes has consisted of low- to moderate ET intensity. However, a growing body of evidence suggests that higher exercise intensities may be superior to moderate intensity for maximizing health outcomes. The primary objective of this review is to discuss how aerobic high-intensity interval training (HIIT) as compared to moderate continuous training may maximize outcomes, and to provide practical advices for successful clinical and home-based HIIT. Copyright © 2017. Published by Elsevier Inc.

Exercise and Self-Reported Limitations in Patients with Inflammatory Bowel Disease.

PubMed

DeFilippis, Ersilia M; Tabani, Saniya; Warren, Ryan U; Christos, Paul J; Bosworth, Brian P; Scherl, Ellen J

2016-01-01

Limited evidence suggests that exercise may have beneficial, anti-inflammatory effects in patients with inflammatory bowel disease (IBD). The purpose of this study was to evaluate the prevalence of exercise in patients with IBD and the limitations they experience secondary to their disease. Two hundred and fifty IBD patients were prospectively enrolled in this study at an academic medical center at the time of their outpatient visits between March and October 2013. Subjects were asked to complete a one-time survey that asks questions about medical and surgical history, exercise frequency and intensity, and the limitations and barriers they experience. Two hundred and twenty-seven patients (148 female patients) completed the survey. Crohn's disease was present in 140 patients (61.5 %), while 87 had ulcerative colitis. Forty-one patients (16.4 %) never exercised, 82 patients (32.8 %) exercised 1-2 times per week, 59 (23.6 %) exercised 3-4 times per week, and 45 (18.0 %) exercised more than four times per week. Of the 186 who regularly exercise, 95 (51 %) reported moderate exercise intensity, 61 (33 %) reported light intensity, and 30 (16 %) reported vigorous intensity. Ninety-nine patients (44 %) reported that their IBD limited their exercise for reasons including fatigue (n = 81), joint pain (n = 37), embarrassment (n = 23), weakness (n = 21), and others. Although they may benefit from exercise, IBD patients experience considerable barriers to regular exercise secondary to the relapsing and remitting nature of IBD. Larger studies are needed to determine the effects of exercise on disease symptomatology and activity.

Kinetic Analysis of Horizontal Plyometric Exercise Intensity.

PubMed

Kossow, Andrew J; Ebben, William P

2018-05-01

Kossow, AJ, DeChiara, TG, Neahous, SM, and Ebben, WP. Kinetic analysis of horizontal plyometric exercise intensity. J Strength Cond Res 32(5): 1222-1229, 2018-Plyometric exercises are frequently performed as part of a strength and conditioning program. Most studies assessed the kinetics of plyometric exercises primarily performed in the vertical plane. The purpose of this study was to evaluate the multiplanar kinetic characteristics of a variety of plyometric exercises, which have a significant horizontal component. This study also sought to assess sex differences in the intensity progression of these exercises. Ten men and 10 women served as subjects. The subjects performed a variety of plyometric exercises including the double-leg hop, standing long jump, single-leg standing long jump, bounding, skipping, power skipping, cone hops, and 45.72-cm hurdle hops. Subjects also performed the countermovement jump for comparison. All plyometric exercises were evaluated using a force platform. Dependent variables included the landing rate of force development and landing ground reaction forces for each exercise in the vertical, frontal, and sagittal planes. A 2-way mixed analysis of variance with repeated-measures for plyometric exercise type demonstrated main effects for exercise type for all dependent variables (p ≤ 0.001). There was no significant interaction between plyometric exercise type and sex for any of the variable assessed. Bonferroni-adjusted pairwise comparisons identified a number of differences between the plyometric exercises for the dependent variables assessed (p ≤ 0.05). These findings should be used to guide practitioners in the progression of plyometric exercise intensity, and thus program design, for those who require significant horizontal power in their sport.

Strength and Cardiorespiratory Exercise Rehabilitation for Severely Burned Patients During Intensive Care Units: A Survey of Practice.

PubMed

Cambiaso-Daniel, Janos; Parry, Ingrid; Rivas, Eric; Kemp-Offenberg, Jennifer; Sen, Soman; Rizzo, Julie A; Serghiou, Michael A; Kowalske, Karen; Wolf, Steven E; Herndon, David N; Suman, Oscar E

2018-03-22

Minimizing the deconditioning of burn injury through early rehabilitation programs (RP) in the intensive care unit (ICU) is of importance for improving the recovery time. The aim of this study was to assess current standard of care (SOC) for early ICU exercise programs in major burn centers. We designed a survey investigating exercise RP on the ICU for burn patients with >30% total burned surface area. The survey was composed of 23 questions and submitted electronically via SurveyMonkey® to six major (pediatric and adult) burn centers in Texas and California. All centers responded and reported exercise as part of their RP on the ICU. The characteristics of exercises implemented were not uniform. All centers reported to perform resistive and aerobic exercises but only 83% reported isotonic and isometric exercises. Determination of intensity of exercise varied with 50% of centers using patient tolerance and 17% using vital signs. Frequency of isotonic, isometric, aerobic, and resistive exercise was reported as daily by 80%, 80%, 83%, and 50% of centers, respectively. Duration for all types of exercises was extremely variable. Mobilization was used as a form of exercise by 100% of burn centers. Our results demonstrate that although early RP seem to be integral during burn survivor's ICU stay, no SOC exists. Moreover, early RP are inconsistently administered and large variations exist in frequency, intensity, duration, and type of exercise. Thus, future prospective studies investigating the various components of exercise interventions are needed to establish a SOC and determine how and if early exercise benefits the burn survivor.

The effect of higher ATP cost of contraction on the metabolic response to graded exercise in patients with chronic obstructive pulmonary disease.

PubMed

Layec, Gwenael; Haseler, Luke J; Richardson, Russell S

2012-03-01

To better understand the metabolic implications of a higher ATP cost of contraction in chronic obstructive pulmonary disease (COPD), we used (31)P-magnetic resonance spectroscopy ((31)P-MRS) to examine muscle energetics and pH in response to graded exercise. Specifically, in six patients and six well-matched healthy controls, we determined the intracellular threshold for pH (T(pH)) and inorganic phosphate-to-phosphocreatine ratio (T(Pi/PCr)) during progressive dynamic plantar flexion exercise with work rate expressed as both absolute and relative intensity. Patients with COPD displayed a lower peak power output (WRmax) compared with controls (controls 25 ± 4 W, COPD 15 ± 5 W, P = 0.01) while end-exercise pH (controls 6.79 ± 0.15, COPD 6.76 ± 0.21, P = 0.87) and PCr consumption (controls 82 ± 10%, COPD 70 ± 18%, P = 0.26) were similar between groups. Both T(pH) and T(Pi/PCr) occurred at a significantly lower absolute work rate in patients with COPD compared with controls (controls: 14.7 ± 2.4 W for T(pH) and 15.3 ± 2.4 W for T(Pi/PCr); COPD: 9.7 ± 4.5 W for T(pH) and 10.0 ± 4.6 W for T(Pi/PCr), P < 0.05), but these thresholds occurred at the same percentage of WRmax (controls: 63 ± 11% WRmax for T(pH) and 67 ± 18% WRmax for T(Pi/PCr); COPD: 59 ± 9% WRmax for T(pH) and 61 ± 12% WRmax for T(Pi/PCr), P > 0.05). Indexes of mitochondrial function, the PCr recovery time constant (controls 42 ± 7 s, COPD 45 ± 11 s, P = 0.66) and the PCr resynthesis rate (controls 105 ± 21%/min, COPD 91 ± 31%/min, P = 0.43) were similar between groups. In combination, these results reveal that when energy demand is normalized to WRmax, as a consequence of higher ATP cost of contraction, patients with COPD display the same metabolic pattern as healthy subjects, suggesting that skeletal muscle energy production is well preserved in these patients.

Three consecutive days of interval runs to exhaustion affects lymphocyte subset apoptosis and migration.

PubMed

Navalta, James W; Tibana, Ramires Alsamir; Fedor, Elizabeth A; Vieira, Amilton; Prestes, Jonato

2014-01-01

This investigation assessed the lymphocyte subset response to three days of intermittent run exercise to exhaustion. Twelve healthy college-aged males (n = 8) and females (n = 4) (age = 26 ± 4 years; height = 170.2 ± 10 cm; body mass = 75 ± 18 kg) completed an exertion test (maximal running speed and VO2max) and later performed three consecutive days of an intermittent run protocol to exhaustion (30 sec at maximal running speed and 30 sec at half of the maximal running speed). Blood was collected before exercise (PRE) and immediately following the treadmill bout (POST) each day. When the absolute change from baseline was evaluated (i. e., Δ baseline), a significant change in CD4+ and CD8+ for CX3CR1 cells was observed by completion of the third day. Significant changes in both apoptosis and migration were observed following two consecutive days in CD19+ lymphocytes, and the influence of apoptosis persisted following the third day. Given these lymphocyte responses, it is recommended that a rest day be incorporated following two consecutive days of a high-intensity intermittent run program to minimize immune cell modulations and reduce potential susceptibility.

Sustained effect of resistance training on blood pressure and hand grip strength following a detraining period in elderly hypertensive women: a pilot study

PubMed Central

Nascimento, Dahan da Cunha; Tibana, Ramires Alsamir; Benik, Franklin M; Fontana, Keila Elizabeth; Neto, Frederico Ribeiro; de Santana, Frederico Santos; Santos-Neto, Leopoldo; Silva, Renato André Sousa; Silva, Alessandro Oliveira; Farias, Darlan Lopes; Balsamo, Sandor; Prestes, Jonato

2014-01-01

Introduction Hypertension is the most prevalent modifiable risk factor with a high prevalence among older adults. Exercise is a nonpharmacological treatment shown to benefit all patients with hypertension. Objective This study examined the effects of a 14-week moderate intensity resistance training program (RT) on the maintenance of blood pressure and hand grip strength during an extended detraining period in elderly hypertensive women. Methods Twelve hypertensive sedentary elderly women completed 14 weeks of whole body RT at a moderate perceived exertion following a detraining period of 14 weeks. Results Following the training period, participants demonstrated an increase in absolute hand grip strength (P=0.001), relative hand grip strength (P=0.032) and a decrease of systolic (P=0.001), diastolic (P=0.008), and mean blood pressure (P=0.002) when compared to pre-exercise values. In addition, these effects were sustained after 14 weeks of detraining. Conclusion Resistance training may be a valuable method to improve muscular strength and blood pressure in elderly people with benefits being maintained up to 14 weeks following training cessation. PMID:24477221

Do 'mind over muscle' strategies work? Examining the effects of attentional association and dissociation on exertional, affective and physiological responses to exercise.

PubMed

Lind, Erik; Welch, Amy S; Ekkekakis, Panteleimon

2009-01-01

Despite the well established physical and psychological benefits derived from leading a physically active life, rates of sedentary behaviour remain high. Dropout and non-compliance are major contributors to the problem of physical inactivity. Perceptions of exertion, affective responses (e.g. displeasure or discomfort), and physiological stress could make the exercise experience aversive, particularly for beginners. Shifting one's attentional focus towards environmental stimuli (dissociation) instead of one's body (association) has been theorized to enhance psychological responses and attenuate physiological stress. Research evidence on the effectiveness of attentional focus strategies, however, has been perplexing, covering the entire gamut of possible outcomes (association and dissociation having been shown to be both effective and ineffective). This article examines the effects of manipulations of attentional focus on exertional and affective responses, as well as on exercise economy and tolerance. The possible roles of the characteristics of the exercise stimulus (intensity, duration) and the exercise participants, methodological issues, and limitations of experimental designs are discussed. In particular, the critical role of exercise intensity is emphasized. Dissociative strategies may be more effective in reducing perceptions of exertion and enhancing affective responses at low to moderate exercise intensities, but their effectiveness may be diminished at higher and near-maximal levels, at which physiological cues dominate. Conversely, associative strategies could enable the exerciser to regulate intensity to avoid injury or overexertion. Thus, depending on intensity, both strategies have a place in the 'toolbox' of the public health or exercise practitioner as methods of enhancing the exercise experience and promoting long-term compliance.

Understanding the factors that effect maximal fat oxidation.

PubMed

Purdom, Troy; Kravitz, Len; Dokladny, Karol; Mermier, Christine

2018-01-01

Lipids as a fuel source for energy supply during submaximal exercise originate from subcutaneous adipose tissue derived fatty acids (FA), intramuscular triacylglycerides (IMTG), cholesterol and dietary fat. These sources of fat contribute to fatty acid oxidation (FAox) in various ways. The regulation and utilization of FAs in a maximal capacity occur primarily at exercise intensities between 45 and 65% VO 2max , is known as maximal fat oxidation (MFO), and is measured in g/min. Fatty acid oxidation occurs during submaximal exercise intensities, but is also complimentary to carbohydrate oxidation (CHOox). Due to limitations within FA transport across the cell and mitochondrial membranes, FAox is limited at higher exercise intensities. The point at which FAox reaches maximum and begins to decline is referred to as the crossover point. Exercise intensities that exceed the crossover point (~65% VO 2max ) utilize CHO as the predominant fuel source for energy supply. Training status, exercise intensity, exercise duration, sex differences, and nutrition have all been shown to affect cellular expression responsible for FAox rate. Each stimulus affects the process of FAox differently, resulting in specific adaptions that influence endurance exercise performance. Endurance training, specifically long duration (>2 h) facilitate adaptations that alter both the origin of FAs and FAox rate. Additionally, the influence of sex and nutrition on FAox are discussed. Finally, the role of FAox in the improvement of performance during endurance training is discussed.

Muscle metabolic responses during high-intensity intermittent exercise measured by 31P-MRS: relationship to the critical power concept

PubMed Central

Chidnok, Weerapong; DiMenna, Fred J.; Fulford, Jonathan; Bailey, Stephen J.; Skiba, Philip F.; Vanhatalo, Anni

2013-01-01

We investigated the responses of intramuscular phosphate-linked metabolites and pH (as assessed by 31P-MRS) during intermittent high-intensity exercise protocols performed with different recovery-interval durations. Following estimation of the parameters of the power-duration relationship, i.e., the critical power (CP) and curvature constant (W′), for severe-intensity constant-power exercise, nine male subjects completed three intermittent exercise protocols to exhaustion where periods of high-intensity constant-power exercise (60 s) were separated by different durations of passive recovery (18 s, 30 s and 48 s). The tolerable duration of exercise was 304 ± 68 s, 516 ± 142 s, and 847 ± 240 s for the 18-s, 30-s, and 48-s recovery protocols, respectively (P < 0.05). The work done >CP (W>CP) was significantly greater for all intermittent protocols compared with the subjects' W′, and this difference became progressively greater as recovery-interval duration was increased. The restoration of intramuscular phosphocreatine concentration during recovery was greatest, intermediate, and least for 48 s, 30 s, and 18 s of recovery, respectively (P < 0.05). The W>CP in excess of W′ increased with greater durations of recovery, and this was correlated with the mean magnitude of muscle phosphocreatine reconstitution between work intervals (r = 0.61; P < 0.01). The results of this study show that during intermittent high-intensity exercise, recovery intervals allow intramuscular homeostasis to be restored, with the degree of restoration being related to the duration of the recovery interval. Consequently, and consistent with the intermittent CP model, the ability to perform W>CP during intermittent high-intensity exercise and, therefore, exercise tolerance, increases when recovery-interval duration is extended. PMID:24068048

Intensive walking exercise for lower extremity peripheral arterial disease: A systematic review and meta-analysis.

PubMed

Lyu, Xiafei; Li, Sheyu; Peng, Shifeng; Cai, Huimin; Liu, Guanjian; Ran, Xingwu

2016-05-01

Supervised treadmill exercise is the recommended therapy for peripheral arterial disease (PAD) patients with intermittent claudication (IC). However, most PAD patients do not exhibit typical symptoms of IC. The aim of the present study was to explore the efficacy and safety of intensive walking exercise in PAD patients with and without IC. The PubMed, Embase and Cochrane Library databases were systematically searched. Randomized controlled trials comparing the effects of intensive walking exercise with usual care in patients with PAD were included for systematic review and meta-analysis. Eighteen trials with 1200 patients were eligible for the present analysis. Compared with usual care, intensive walking exercise significantly improved the maximal walking distance (MWD), pain-free walking distance, and the 6-min walking distance in patients with PAD (P < 0.00001 for all). Subgroup analyses indicated that a lesser improvement in MWD was observed in the subgroup with more diabetes patients, and that the subgroup with better baseline walking ability exhibited greater improvement in walking performance. In addition, similar improvements in walking performance were observed for exercise programs of different durations and modalities. No significant difference was found in adverse events between the intensive walking and usual care groups (relative risk 0.84; 95% confidence interval 0.51, 1.39; P = 0.50). Regardless of exercise length and modality, regularly intensive walking exercise improves walking ability in PAD patients more than usual care. The presence of diabetes may attenuate the improvements in walking performance in patients with PAD following exercise. © 2015 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

Can supine recovery mitigate the exercise intensity dependent attenuation of post-exercise heat loss responses?

PubMed

Kenny, Glen P; Gagnon, Daniel; Jay, Ollie; McInnis, Natalie H; Journeay, W Shane; Reardon, Francis D

2008-08-01

Cutaneous vascular conductance (CVC) and sweat rate are subject to non-thermal baroreflex-mediated attenuation post-exercise. Various recovery modalities have been effective in attenuating these decreases in CVC and sweat rate post-exercise. However, the interaction of recovery posture and preceding exercise intensity on post-exercise thermoregulation remains unresolved. We evaluated the combined effect of supine recovery and exercise intensity on post-exercise cardiovascular and thermal responses relative to an upright seated posture. Seven females performed 15 min of cycling ergometry at low- (LIE, 55% maximal oxygen consumption) or high-(HIE, 85% maximal oxygen consumption) intensity followed by 60 min of recovery in either an upright seated or supine posture. Esophageal temperature, CVC, sweat rate, cardiac output, stroke volume, heart rate, total peripheral resistance, and mean arterial pressure (MAP) were measured at baseline, at end-exercise, and at 2, 5, 12, 20, and every 10 min thereafter until the end of recovery. MAP and stroke volume were maintained during supine recovery to a greater extent relative to an upright seated recovery following HIE (p

Blood flow patterns during incremental and steady-state aerobic exercise.

PubMed

Coovert, Daniel; Evans, LeVisa D; Jarrett, Steven; Lima, Carla; Lima, Natalia; Gurovich, Alvaro N

2017-05-30

Endothelial shear stress (ESS) is a physiological stimulus for vascular homeostasis, highly dependent on blood flow patterns. Exercise-induced ESS might be beneficial on vascular health. However, it is unclear what type of ESS aerobic exercise (AX) produces. The aims of this study are to characterize exercise-induced blood flow patterns during incremental and steady-state AX. We expect blood flow pattern during exercise will be intensity-dependent and bidirectional. Six college-aged students (2 males and 4 females) were recruited to perform 2 exercise tests on cycleergometer. First, an 8-12-min incremental test (Test 1) where oxygen uptake (VO2), heart rate (HR), blood pressure (BP), and blood lactate (La) were measured at rest and after each 2-min step. Then, at least 48-hr. after the first test, a 3-step steady state exercise test (Test 2) was performed measuring VO2, HR, BP, and La. The three steps were performed at the following exercise intensities according to La: 0-2 mmol/L, 2-4 mmol/L, and 4-6 mmol/L. During both tests, blood flow patterns were determined by high-definition ultrasound and Doppler on the brachial artery. These measurements allowed to determine blood flow velocities and directions during exercise. On Test 1 VO2, HR, BP, La, and antegrade blood flow velocity significantly increased in an intensity-dependent manner (repeated measures ANOVA, p<0.05). Retrograde blood flow velocity did not significantly change during Test 1. On Test 2 all the previous variables significantly increased in an intensity-dependent manner (repeated measures ANOVA, p<0.05). These results support the hypothesis that exercise induced ESS might be increased in an intensity-dependent way and blood flow patterns during incremental and steady-state exercises include both antegrade and retrograde blood flows.

The effect of exercise intensity and excess postexercise oxygen consumption on postprandial blood lipids in physically inactive men.

PubMed

Littlefield, Laurel A; Papadakis, Zacharias; Rogers, Katie M; Moncada-Jiménez, José; Taylor, J Kyle; Grandjean, Peter W

2017-09-01

Reductions in postprandial lipemia have been observed following aerobic exercise of sufficient energy expenditure. Increased excess postexercise oxygen consumption (EPOC) has been documented when comparing high- versus low-intensity exercise. The contribution of EPOC energy expenditure to alterations in postprandial lipemia has not been determined. The purpose of this study was to evaluate the effects of low- and high-intensity exercise on postprandial lipemia in healthy, sedentary, overweight and obese men (age, 43 ± 10 years; peak oxygen consumption, 31.1 ± 7.5 mL·kg -1 ·min -1 ; body mass index, 31.8 ± 4.5 kg/m 2 ) and to determine the contribution of EPOC to reductions in postprandial lipemia. Participants completed 4 conditions: nonexercise control, low-intensity exercise at 40%-50% oxygen uptake reserve (LI), high-intensity exercise at 70%-80% oxygen uptake reserve (HI), and HI plus EPOC re-feeding (HI+EERM), where the difference in EPOC energy expenditure between LI and HI was re-fed in the form of a sports nutrition bar (Premier Nutrition Corp., Emeryville, Calif., USA). Two hours following exercise participants ingested a high-fat (1010 kcals, 99 g sat fat) test meal. Blood samples were obtained before exercise, before the test meal, and at 2, 4, and 6 h postprandially. Triglyceride incremental area under the curve was significantly reduced following LI, HI, and HI+EERM when compared with nonexercise control (p < 0.05) with no differences between the exercise conditions (p > 0.05). In conclusions, prior LI and HI exercise equally attenuated postprandial triglyceride responses to the test meal. The extra energy expended during EPOC does not contribute significantly to exercise energy expenditure or to reductions in postprandial lipemia in overweight men.

Effects of Different Exercise Intensities with Isoenergetic Expenditures on C-Reactive Protein and Blood Lipid Levels

ERIC Educational Resources Information Center

Tsao, Te Hung; Yang, Chang Bin; Hsu, Chin Hsing

2012-01-01

We investigated the effects of different exercise intensities on C-reactive protein (CRP), and whether changes in CRP levels correlated with blood lipid levels. Ten men exercised at 25%, 65%, and 85% of their maximum oxygen consumption rates. Participants' blood was analyzed for CRP and blood lipid levels before and after the exercise sessions.…

Cardiopulmonary exercise testing early after stroke using feedback-controlled robotics-assisted treadmill exercise: test-retest reliability and repeatability.

PubMed

Stoller, Oliver; de Bruin, Eling D; Schindelholz, Matthias; Schuster-Amft, Corina; de Bie, Rob A; Hunt, Kenneth J

2014-10-11

Exercise capacity is seriously reduced after stroke. While cardiopulmonary assessment and intervention strategies have been validated for the mildly and moderately impaired populations post-stroke, there is a lack of effective concepts for stroke survivors suffering from severe motor limitations. This study investigated the test-retest reliability and repeatability of cardiopulmonary exercise testing (CPET) using feedback-controlled robotics-assisted treadmill exercise (FC-RATE) in severely motor impaired individuals early after stroke. 20 subjects (age 44-84 years, <6 month post-stroke) with severe motor limitations (Functional Ambulatory Classification 0-2) were selected for consecutive constant load testing (CLT) and incremental exercise testing (IET) within a powered exoskeleton, synchronised with a treadmill and a body weight support system. A manual human-in-the-loop feedback system was used to guide individual work rate levels. Outcome variables focussed on standard cardiopulmonary performance parameters. Relative and absolute test-retest reliability were assessed by intraclass correlation coefficients (ICC), standard error of the measurement (SEM), and minimal detectable change (MDC). Mean difference, limits of agreement, and coefficient of variation (CoV) were estimated to assess repeatability. Peak performance parameters during IET yielded good to excellent relative reliability: absolute peak oxygen uptake (ICC =0.82), relative peak oxygen uptake (ICC =0.72), peak work rate (ICC =0.91), peak heart rate (ICC =0.80), absolute gas exchange threshold (ICC =0.91), relative gas exchange threshold (ICC =0.88), oxygen cost of work (ICC =0.87), oxygen pulse at peak oxygen uptake (ICC =0.92), ventilation rate versus carbon dioxide output slope (ICC =0.78). For these variables, SEM was 4-13%, MDC 12-36%, and CoV 0.10-0.36. CLT revealed high mean differences and insufficient test-retest reliability for all variables studied. This study presents first evidence on reliability and repeatability for CPET in severely motor impaired individuals early after stroke using a feedback-controlled robotics-assisted treadmill. The results demonstrate good to excellent test-retest reliability and appropriate repeatability for the most important peak cardiopulmonary performance parameters. These findings have important implications for the design and implementation of cardiovascular exercise interventions in severely impaired populations. Future research needs to develop advanced control strategies to enable the true limit of functional exercise capacity to be reached and to further assess test-retest reliability and repeatability in larger samples.

Efficacy of Carbohydrate Ingestion on CrossFit Exercise Performance

PubMed Central

Rountree, Jaden A.; Krings, Ben M.; Peterson, Timothy J.; Thigpen, Adam G.; McAllister, Matthew J.; Holmes, Megan E.

2017-01-01

The efficacy of carbohydrate (CHO) ingestion during high-intensity strength and conditioning type exercise has yield mixed results. However, little is known about shorter duration high-intensity exercise such as CrossFit. The purpose of this study was to investigate the performance impact of CHO ingestion during high-intensity exercise sessions lasting approximately 30 min. Eight healthy males participated in a total of four trials; two familiarizations, a CHO trial, and a similarly flavored, non-caloric placebo (PLA) trial. CrossFit’s “Fight Gone Bad Five” (FGBF) workout of the day was the exercise model which incorporated five rounds of maximal repetition exercises, wall throw, box jump, sumo deadlift high pull, push press, and rowing, followed by one minute of rest. Total repetitions and calories expended were summated from each round to quantify total work (FGBF score). No difference was found for the total work between CHO (321 ± 51) or PLA (314 ± 52) trials (p = 0.38). There were also no main effects (p > 0.05) for treatment comparing exercise performance across rounds. Based on the findings of this study, it does not appear that ingestion of CHO during short duration, high-intensity CrossFit exercise will provide a beneficial performance effect.

Oxidative stress does not influence local sweat rate during high-intensity exercise.

PubMed

Meade, Robert D; Fujii, Naoto; Poirier, Martin P; Boulay, Pierre; Sigal, Ronald J; Kenny, Glen P

2018-02-01

What is the central question of this study? We evaluated whether oxidative stress attenuates the contribution of nitric oxide to sweating during high-intensity exercise. What is the main finding and its importance? In contrast to our previous report of an oxidative stress-mediated reduction in nitric oxide-dependent cutaneous vasodilatation in this cohort during intense exercise, we demonstrated no influence of local ascorbate administration on the sweating response during moderate- (∼51% peak oxygen uptake) or high-intensity exercise (∼72% peak oxygen uptake). These new findings provide important mechanistic insight into how exercise-induced oxidative stress impacts sudomotor activity. Nitric oxide (NO)-dependent sweating is diminished during high- but not moderate-intensity exercise. We evaluated whether this impairment stems from increased oxidative stress during high-intensity exercise. On two separate days, 11 young (24 ± 4 years) men cycled in the heat (35°C) at a moderate [500 W; 52 ± 6% peak oxygen uptake (V̇O2 peak )] or high (700 W; 71 ± 5% V̇O2 peak ) rate of metabolic heat production. Each session included two 30 min exercise bouts separated by a 20 min recovery period. Local sweat rate was monitored at four forearm skin sites continuously perfused via intradermal microdialysis with the following: (i) lactated Ringer solution (Control); (ii) 10 mm ascorbate (Ascorbate; non-selective antioxidant); (iii) 10 mm N G -nitro-l-arginine methyl ester (l-NAME; NO synthase inhibitor); or (iv) 10 mm ascorbate plus 10 mm l-NAME (Ascorbate + l-NAME). During moderate exercise, sweat rate was attenuated at the l-NAME and Ascorbate + l-NAME sites (both ∼1.0 mg min -1  cm -2 ; all P < 0.05) but not at the Ascorbate site (∼1.1 mg min -1  cm -2 ; both P ≥ 0.28) in comparison to the Control site (∼1.1 mg min -1  cm -2 ). However, no differences were observed between treatment sites (∼1.4 mg min -1  cm -2 ; P = 0.75) during high-intensity exercise. We conclude that diminished NO-dependent sweating during intense exercise occurs independent of oxidative stress. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Higher exercise intensity delays postexercise recovery of impedance-derived cardiac sympathetic activity.

PubMed

Michael, Scott; Jay, Ollie; Graham, Kenneth S; Davis, Glen M

2017-08-01

Systolic time intervals (STIs) provide noninvasive insights into cardiac sympathetic neural activity (cSNA). As the effect of exercise intensity on postexercise STI recovery is unclear, this study investigated the STI recovery profile after different exercise intensities. Eleven healthy males cycled for 8 min at 3 separate intensities: LOW (40%-45%), MOD (75%-80%), and HIGH (90%-95%) of heart-rate (HR) reserve. Bio-impedance cardiography was used to assess STIs - primarily pre-ejection period (PEP; inversely correlated with cSNA), as well as left ventricular ejection time (LVET) and PEP:LVET - during 10 min seated recovery immediately postexercise. Heart-rate variability (HRV), i.e., natural-logarithm of root mean square of successive differences (Ln-RMSSD), was calculated as an index of cardiac parasympathetic neural activity (cPNA). Higher preceding exercise intensity elicited a slower recovery of HR and Ln-RMSSD (p < 0.001), and these measures did not return to baseline by 10 min following any intensity (p ≤ 0.009). Recovery of STIs was also slower following higher intensity exercise (p ≤ 0.002). By 30 s postexercise, higher preceding intensity resulted in a lower PEP (98 ± 14 ms, 75 ± 6 ms, 66 ± 5 ms for LOW, MOD, and HIGH, respectively, p < 0.001). PEP recovered to baseline (143 ± 11 ms) by 5 min following LOW (139 ± 13 ms, p = 0.590) and by 10 min following MOD (145 ± 17 ms, p = 0.602), but was still suppressed at 10 min following HIGH (123 ± 21 ms, p = 0.012). Higher preceding exercise intensity attenuated the recovery of indices for cSNA (from STIs) and cPNA (from HRV) in a graded dose-response fashion. While exercise intensity must be considered, acute recovery may be a valuable period during which to concurrently monitor these noninvasive indices, to identify potentially abnormal cardiac autonomic responses.

The Effects of Different Passive Static Stretching Intensities on Recovery from Unaccustomed Eccentric Exercise - A Randomized Controlled Trial.

PubMed

Apostolopoulos, Nikos C; Lahart, Ian M; Plyley, Michael J; Taunton, Jack; Nevill, Alan M; Koutedakis, Yiannis; Wyon, Matthew; Metsios, George S

2018-03-12

Effects of passive static stretching intensity on recovery from unaccustomed eccentric exercise of right knee extensors was investigated in 30 recreationally active males randomly allocated into three groups: high-intensity (70-80% maximum perceived stretch), low-intensity (30-40% maximum perceived stretch), and control. Both stretching groups performed 3 sets of passive static stretching exercises of 60s each for hamstrings, hip flexors, and quadriceps, over 3 consecutive days, post-unaccustomed eccentric exercise. Muscle function (eccentric and isometric peak torque) and blood biomarkers (CK and CRP) were measured before (baseline) and after (24, 48, and 72h) unaccustomed eccentric exercise. Perceived muscle soreness scores were collected immediately (time 0), and after 24, 48, and 72h post-exercise. Statistical time x condition interactions observed only for eccentric peak torque (p=.008). Magnitude-based inference analyses revealed low-intensity stretching had most likely, very likely, or likely beneficial effects on perceived muscle soreness (48-72h and 0-72h) and eccentric peak torque (baseline-24h and baseline-72h), compared with high-intensity stretching. Compared with control, low-intensity stretching had very likely or likely beneficial effects on perceived muscle soreness (0-24h and 0-72h), eccentric peak torque (baseline-48h and baseline-72h), and isometric peak torque (baseline-72h). High-intensity stretching had likely beneficial effects on eccentric peak torque (baseline-48h), but likely harmful effects eccentric peak torque (baseline-24h) and CK (baseline-48h and baseline-72h), compared with control. Therefore, low-intensity stretching is likely to result in small-to-moderate beneficial effects on perceived muscle soreness and recovery of muscle function post-unaccustomed eccentric exercise, but not markers of muscle damage and inflammation, compared with high-intensity or no stretching.

The influence of exercise intensity on heat acclimation in trained subjects.

PubMed

Houmard, J A; Costill, D L; Davis, J A; Mitchell, J B; Pascoe, D D; Robergs, R A

1990-10-01

Low-intensity exercise (less than or equal to 50% VO2max) has been demonstrated to produce heat acclimation (HA) in trained subjects. The purpose of this study was to determine whether shorter-duration, moderate-intensity exercise would also result in HA. Nine trained runners performed two 9-d exercise heat-stress protocols. Each protocol consisted of a 90-min heat tolerance test on days 1 (HTT1) and 9 (HTT2). On days 2-8 the subjects exercised at 50% VO2max for 60 min.d-1 (T50) or at 75% VO2max for 30-35 min.d-1 (T75). Final HTT2 heart rate and rectal temperature (Tr) were significantly (P less than 0.001) reduced, as compared to HTT1, with no differences between T50 and T75. Both protocols resulted in significant (P less than 0.05) reductions in HTT2 pre-exercise Tr and total exercising caloric expenditure, both of which are known to contribute to HA. No changes in resting plasma volume, osmolality, protein, post-HTT aldosterone, and exercising sweat rate were observed. These results demonstrate that equal levels of HA were obtained with T50 and T75, which suggests that moderate-intensity, short-duration exercise in the heat can produce HA in trained subjects.

Revisiting the relationship between exercise heart rate and music tempo preference.

PubMed

Karageorghis, Costas I; Jones, Leighton; Priest, David-Lee; Akers, Rose I; Clarke, Adam; Perry, Jennifer M; Reddick, Benjamin T; Bishop, Daniel T; Lim, Harry B T

2011-06-01

In the present study, we investigated a hypothesized quartic relationship (meaning three inflection points) between exercise heart rate (HR) and preferred music tempo. Initial theoretical predictions suggested a positive linear relationship (Iwanaga, 1995a, 1995b); however, recent experimental work has shown that as exercise HR increases, step changes and plateaus that punctuate the profile of music tempo preference may occur (Karageorghis, Jones, & Stuart, 2008). Tempi bands consisted of slow (95-100 bpm), medium (115-120 bpm), fast (135-140 bpm), and very fast (155-160 bpm) music. Twenty-eight active undergraduate students cycled at exercise intensities representing 40, 50, 60, 70, 80, and 90% of their maximal HR reserve while their music preference was assessed using a 10-point scale. The Exercise Intensity x Music Tempo interaction was significant, F(6.16, 160.05) = 7.08, p < .001, 7,2 = .21, as was the test for both cubic and quartic trajectories in the exercise HR-preferred-music-tempo relationship (p < .001). Whereas slow tempo music was not preferred at any exercise intensity, preference for fast tempo increased, relative to medium and very fast tempo music, as exercise intensity increased. The implications for the prescription of music in exercise and physical activity contexts are discussed.

High-intensity compared to moderate-intensity training for exercise initiation, enjoyment, adherence, and intentions: an intervention study.

PubMed

Heinrich, Katie M; Patel, Pratik M; O'Neal, Joshua L; Heinrich, Bryan S

2014-08-03

Understanding exercise participation for overweight and obese adults is critical for preventing comorbid conditions. Group-based high-intensity functional training (HIFT) provides time-efficient aerobic and resistance exercise at self-selected intensity levels which can increase adherence; behavioral responses to HIFT are unknown. This study examined effects of HIFT as compared to moderate-intensity aerobic and resistance training (ART) on exercise initiation, enjoyment, adherence, and intentions. A stratified, randomized two-group pre-test posttest intervention was conducted for eight weeks in 2012 with analysis in 2013. Participants (n = 23) were stratified by median age (< or ≥ 28) and body mass index (BMI; < or ≥ 30.5). Participants were physically inactive with an average BMI of 31.1 ± 3.5 kg/m2, body fat percentage of 42.0 ± 7.4%, weight of 89.5 ± 14.2 kg, and ages 26.8 ± 5.9 years. Most participants were white, college educated, female, and married/engaged. Both groups completed 3 training sessions per week. The ART group completed 50 minutes of moderate aerobic exercise each session and full-body resistance training on two sessions per week. The HIFT group completed 60-minute sessions of CrossFit™ with actual workouts ranging from 5-30 minutes. Participants completed baseline and posttest questionnaires indicating reasons for exercise initiation (baseline), exercise enjoyment, and exercise intentions (posttest). Adherence was defined as completing 90% of exercise sessions. Daily workout times were recorded. Participants provided mostly intrinsic reasons for exercise initiation. Eighteen participants adhered (ART = 9, 81.8%; HIFT = 9, 75%). HIFT dropouts (p = .012) and ART participants (p = .009) reported lower baseline exercise enjoyment than HIFT participants, although ART participants improved enjoyment at posttest (p = .005). More HIFT participants planned to continue the same exercise than ART participants (p = .002). No significant changes in BMI or body composition were found. Workouts were shorter for HIFT than ART (p < .001). HIFT participants spent significantly less time exercising per week, yet were able to maintain exercise enjoyment and were more likely to intend to continue. High-intensity exercise options should be included in public health interventions. ClinicalTrials.gov Identifier: http://NCT02185872. Registered 9 July 2014.

Greater impact of acute high-intensity interval exercise on post-exercise executive function compared to moderate-intensity continuous exercise.

PubMed

Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Tanaka, Daichi; Takeuchi, Tatsuya; Hamaoka, Takafumi; Isaka, Tadao; Hashimoto, Takeshi

2016-03-01

Aerobic moderate-intensity continuous exercise (MCE) can improve executive function (EF) acutely, potentially through the activation of both physiological and psychological factors. Recently, high-intensity interval exercise (HIIE) has been reported to be more beneficial for physical adaptation than MCE. Factors for EF improvement can potentially be more enhanced by HIIE than by MCE; but the effects of HIIE on EF remain unknown. Therefore, we aimed to examine to what extent HIIE impacts post-exercise EF immediately after exercise and during post-exercise recovery, compared with traditional MCE. Twelve healthy male subjects performed cycle ergometer exercise based on either HIIE or MCE protocols in a randomized and counterbalanced order. The HIIE protocol consisted of four 4-min bouts at 90% of peak VO2 with 3-min active recovery at 60% of peak VO2. A volume-matched MCE protocol was applied at 60% of peak VO2. To evaluate EF, a color-words Stroop task was performed pre- and post-exercise. Improvement in EF immediately after exercise was the same for the HIIE and MCE protocols. However, the improvement of EF by HIIE was sustained during 30 min of post-exercise recovery, during which MCE returned to the pre-exercise level. The EF response in the post-exercise recovery was associated with changes in physiological and psychological responses. The present findings showed that HIIE and MCE were capable of improving EF. Moreover, HIIE could prolong improvement in EF during post-exercise recovery. For the first time, we suggest that HIIE may be more effective strategy than MCE for improving EF. Copyright © 2015 Elsevier Inc. All rights reserved.

Evaluation of anaerobic threshold in non-pregnant and pregnant rats.

PubMed

Netto, Aline Oliveira; Macedo, Nathália C D; Gallego, Franciane Q; Sinzato, Yuri K; Volpato, Gustavo T; Damasceno, Débora C

2017-01-01

Several studies present different methodologies and results about intensity exercise, and many of them are performed in male rats. However, the impact of different type, intensity, frequency and duration of exercise on female rats needs more investigation. From the analysis of blood lactate concentration during lactate minimum test (LacMin) in the swimming exercise, the anaerobic threshold (AT) was identified, which parameter is defined as the transition point between aerobic and anaerobic metabolism. LacMin test is considered a good indicator of aerobic conditioning and has been used in prescription of training in different exercise modalities. However, there is no evidence of LacMin test in female rats. The objective was to determine AT in non-pregnant and pregnant Wistar rats. The LacMin test was performed and AT defined for mild exercise intensity was from a load equivalent to 1% of body weight (bw), moderate exercise as carrying 4% bw and severe intensity as carrying 7% bw. In pregnant rats, the AT was reached at a lower loading from 5.0% to 5.5% bw, while in non-pregnant the load was from 5.5% to 6.0% bw. Thus, this study was effective to identify exercise intensities in pregnant and non-pregnant rats using anaerobic threshold by LacMin test.

The Effects of Nandrolone Decanoate Along with Prolonged Low-Intensity Exercise on Susceptibility to Ventricular Arrhythmias.

PubMed

Binayi, Fateme; Joukar, Siyavash; Najafipour, Hamid; Karimi, Abdolah; Karimi, Ali; Abdollahi, Farzane; Masumi, Yaser

2016-01-01

We examined the influence of chronic administration of nandrolone decanoate with low-intensity endurance swimming exercise on susceptibility to lethal ventricular arrhythmias in rat. The animal groups included the control group, exercise group (EX), nandrolone group (Nan), vehicle group (Arach), trained vehicle group (Arach + Ex) and trained nandrolone group (Nan + Ex) that treated for 8 weeks. Then, arrhythmia induction was performed by intravenous infusion of aconitine and electrocardiogram recorded. Then, malondialdehyde (MDA), hydroxyproline (HYP) and glutathione peroxidase of heart tissue were measured. Chronic administration of nandrolone with low-intensity endurance swimming exercise had no significant effect on blood pressure, heart rate and basal ECG parameters except RR interval that showed increase (P < 0.05). Low-intensity exercise could prevent the incremental effect of nandrolone on MDA and HYP significantly. It also increased the heart hypertrophy index (P < 0.05) and reduced the abating effect of nandrolone on animal weighting. Nandrolone along with exercise significantly increased the duration of VF (P < 0.05) and reduced the VF latency (P < 0.05). The findings suggest that chronic co-administration of nandrolone with low-intensity endurance swimming exercise to some extent facilitates the occurrence of ventricular fibrillation in rat. Complementary studies are needed to elucidate the involved mechanisms of this abnormality.

Therapeutic physical exercise in neural injury: friend or foe?

PubMed

Park, Kanghui; Lee, Seunghoon; Hong, Yunkyung; Park, Sookyoung; Choi, Jeonghyun; Chang, Kyu-Tae; Kim, Joo-Heon; Hong, Yonggeun

2015-12-01

[Purpose] The intensity of therapeutic physical exercise is complex and sometimes controversial in patients with neural injuries. This review assessed whether therapeutic physical exercise is beneficial according to the intensity of the physical exercise. [Methods] The authors identified clinically or scientifically relevant articles from PubMed that met the inclusion criteria. [Results] Exercise training can improve body strength and lead to the physiological adaptation of skeletal muscles and the nervous system after neural injuries. Furthermore, neurophysiological and neuropathological studies show differences in the beneficial effects of forced therapeutic exercise in patients with severe or mild neural injuries. Forced exercise alters the distribution of muscle fiber types in patients with neural injuries. Based on several animal studies, forced exercise may promote functional recovery following cerebral ischemia via signaling molecules in ischemic brain regions. [Conclusions] This review describes several types of therapeutic forced exercise and the controversy regarding the therapeutic effects in experimental animals versus humans with neural injuries. This review also provides a therapeutic strategy for physical therapists that grades the intensity of forced exercise according to the level of neural injury.

Perceptual Responses to High- and Moderate-Intensity Interval Exercise in Adolescents.

PubMed

Malik, Adam A; Williams, Craig A; Weston, Kathryn L; Barker, Alan R

2018-05-01

Continuous high-intensity exercise is proposed to evoke unpleasant sensations as predicted by the dual-mode theory and may negatively impact on future exercise adherence. Previous studies support unpleasant sensations in affective responses during continuous high-intensity exercise, but the affect experience during high-intensity interval exercise (HIIE) involving brief bursts of high-intensity exercise separated by low-intensity activity is poorly understood in adolescents. We examined the acute affective, enjoyment, and perceived exertion responses to HIIE compared with moderate-intensity interval exercise (MIIE) in adolescents. Thirteen adolescent boys (mean ± SD: age, 14.0 ± 0.5 yr) performed two counterbalanced exercise conditions: 1) HIIE: 8 × 1-min work intervals at 90% maximal aerobic speed; and 2) MIIE: between 9 and 12 × 1-min work intervals at 90% ventilatory threshold where the number of intervals performed were distance-matched to HIIE. HIIE and MIIE work intervals were interspersed with 75 s active recovery at 4 km·h. Affect, enjoyment, and RPE were recorded before, during, and after exercise. Affect responses declined in both conditions but the fall was greater in HIIE than MIIE (P < 0.025, effect size [ES], 0.64 to 0.81). Affect remained positive at the end-work interval for both conditions (MIIE, 2.62 ± 1.50; HIIE, 1.15 ± 2.08 on feeling scale). No enjoyment differences were evident during HIIE and MIIE (P = 0.32), but HIIE elicited greater postexercise enjoyment compared with MIIE (P = 0.01, ES = 0.47). RPE was significantly higher during HIIE than MIIE across all work intervals (all P < 0.03, ES > 0.64). Despite elevated RPE, HIIE did not elicit prominent unpleasant feelings as predicted by the dual-mode theory and was associated with greater postexercise enjoyment responses than MIIE. This study demonstrates the feasibility of the application of HIIE as an alternative form of physical activity in adolescents.

Changes in transverse relaxation time of quadriceps femoris muscles after active recovery exercises with different intensities.

PubMed

Mukaimoto, Takahiro; Semba, Syun; Inoue, Yosuke; Ohno, Makoto

2014-01-01

The purpose of this study was to examine the changes in the metabolic state of quadriceps femoris muscles using transverse relaxation time (T2), measured by muscle functional magnetic resonance (MR) imaging, after inactive or active recovery exercises with different intensities following high-intensity knee-extension exercise. Eight healthy men performed recovery sessions with four different conditions for 20 min after high-intensity knee-extension exercise on separate days. During the recovery session, the participants conducted a light cycle exercise for 20 min using a cycle (50%, 70% and 100% of the lactate threshold (LT), respectively: active recovery), and inactive recovery. The MR images of quadriceps femoris muscles were taken before the trial and after the recovery session every 30 min for 120 min. The percentage changes in T2 for the rectus femoris and vastus medialis muscles after the recovery session in 50% LT and 70% LT were significantly lower than those in either inactive recovery or 100% LT. There were no significant differences in those for vastus lateralis and vastus intermedius muscles among the four trials. The percentage changes in T2 of rectus femoris and vastus medialis muscles after the recovery session in 50% LT and 70% LT decreased to the values before the trial faster than those in either inactive recovery or 100% LT. Those of vastus lateralis and vastus intermedius muscles after the recovery session in 50% LT and 70% LT decreased to the values before the trial faster than those in 100% LT. Although the changes in T2 after active recovery exercises were not uniform in exercised muscles, the results of this study suggest that active recovery exercise with the intensities below LT are more effective to recover the metabolic state of quadriceps femoris muscles after intense exercise than with either intensity at LT or inactive recovery.

Early exercise in critically ill patients enhances short-term functional recovery.

PubMed

Burtin, Chris; Clerckx, Beatrix; Robbeets, Christophe; Ferdinande, Patrick; Langer, Daniel; Troosters, Thierry; Hermans, Greet; Decramer, Marc; Gosselink, Rik

2009-09-01

: To investigate whether a daily exercise session, using a bedside cycle ergometer, is a safe and effective intervention in preventing or attenuating the decrease in functional exercise capacity, functional status, and quadriceps force that is associated with prolonged intensive care unit stay. A prolonged stay in the intensive care unit is associated with muscle dysfunction, which may contribute to an impaired functional status up to 1 yr after hospital discharge. No evidence is available concerning the effectiveness of an early exercise training intervention to prevent these detrimental complications. : Randomized controlled trial. : Medical and surgical intensive care unit at University Hospital Gasthuisberg. : Ninety critically ill patients were included as soon as their cardiorespiratory condition allowed bedside cycling exercise (starting from day 5), given they still had an expected prolonged intensive care unit stay of at least 7 more days. : Both groups received respiratory physiotherapy and a daily standardized passive or active motion session of upper and lower limbs. In addition, the treatment group performed a passive or active exercise training session for 20 mins/day, using a bedside ergometer. : All outcome data are reflective for survivors. Quadriceps force and functional status were assessed at intensive care unit discharge and hospital discharge. Six-minute walking distance was measured at hospital discharge. No adverse events were identified during and immediately after the exercise training. At intensive care unit discharge, quadriceps force and functional status were not different between groups. At hospital discharge, 6-min walking distance, isometric quadriceps force, and the subjective feeling of functional well-being (as measured with "Physical Functioning" item of the Short Form 36 Health Survey questionnaire) were significantly higher in the treatment group (p < .05). : Early exercise training in critically ill intensive care unit survivors enhanced recovery of functional exercise capacity, self-perceived functional status, and muscle force at hospital discharge.

Flavanol-rich cocoa consumption enhances exercise-induced executive function improvements in humans.

PubMed

Tsukamoto, Hayato; Suga, Tadashi; Ishibashi, Aya; Takenaka, Saki; Tanaka, Daichi; Hirano, Yoshitaka; Hamaoka, Takafumi; Goto, Kazushige; Ebi, Kumiko; Isaka, Tadao; Hashimoto, Takeshi

2018-02-01

Aerobic exercise is known to acutely improve cognitive functions, such as executive function (EF) and memory function (MF). Additionally, consumption of flavanol-rich cocoa has been reported to acutely improve cognitive function. The aim of this study was to determine whether high cocoa flavanol (CF; HCF) consumption would enhance exercise-induced improvement in cognitive function. To test this hypothesis, we examined the combined effects of HCF consumption and moderate-intensity exercise on EF and MF during postexercise recovery. Ten healthy young men received either an HCF (563 mg of CF) or energy-matched low CF (LCF; 38 mg of CF) beverage 70 min before exercise in a single-blind counterbalanced manner. The men then performed moderate-intensity cycling exercise at 60% of peak oxygen uptake for 30 min. The participants performed a color-word Stroop task and face-name matching task to evaluate EF and MF, respectively, during six time periods throughout the experimental session. EF significantly improved immediately after exercise compared with before exercise in both conditions. However, EF was higher after HCF consumption than after LCF consumption during all time periods because HCF consumption improved EF before exercise. In contrast, HCF consumption and moderate-intensity exercise did not improve MF throughout the experiment. The present findings demonstrated that HCF consumption before moderate-intensity exercise could enhance exercise-induced improvement in EF, but not in MF. Therefore, we suggest that the combination of HCF consumption and aerobic exercise may be beneficial for improving EF. Copyright © 2017 Elsevier Inc. All rights reserved.

Risk Factors for Osteoporosis are Associated with Stress Fracture in Young Women

DTIC Science & Technology

1989-08-01

underweight were also more likely to have a history of amenorrhea , but these factors appear to be only loosely associated. Exercise serves as the stimalus...eumenorrheic exercising women were 11 unremarka.le (5). Intense exercise may be involved in amenorrhea , as evidenced by the return of menses in some...amenorrheic women who reduce their exercise (27), but amenorrhea is not a necessary consequence of intense exercise (28). Similarly, low weight (or low body

Aerobic Exercise Training in Post-Polio Syndrome: Process Evaluation of a Randomized Controlled Trial

PubMed Central

Voorn, Eric L.; Koopman, Fieke S.; Brehm, Merel A.; Beelen, Anita; de Haan, Arnold; Gerrits, Karin H. L.; Nollet, Frans

2016-01-01

Objective To explore reasons for the lack of efficacy of a high intensity aerobic exercise program in post-polio syndrome (PPS) on cardiorespiratory fitness by evaluating adherence to the training program and effects on muscle function. Design A process evaluation using data from an RCT. Patients Forty-four severely fatigued individuals with PPS were randomized to exercise therapy (n = 22) or usual care (n = 22). Methods Participants in the exercise group were instructed to exercise 3 times weekly for 4 months on a bicycle ergometer (60–70% heart rate reserve). Results The attendance rate was high (median 89%). None of the participants trained within the target heart rate range during >75% of the designated time. Instead, participants exercised at lower intensities, though still around the anaerobic threshold (AT) most of the time. Muscle function did not improve in the exercise group. Conclusion Our results suggest that severely fatigued individuals with PPS cannot adhere to a high intensity aerobic exercise program on a cycle ergometer. Despite exercise intensities around the AT, lower extremity muscle function nor cardiorespiratory fitness improved. Improving the aerobic capacity in PPS is difficult through exercise primarily focusing on the lower extremities, and may require a more individualized approach, including the use of other large muscle groups instead. Trial Registration Netherlands National Trial Register NTR1371 PMID:27419388

Impact of high- and low-intensity targeted exercise training on the type of substrate utilization in obese boys submitted to a hypocaloric diet.

PubMed

Brandou, F; Savy-Pacaux, A M; Marie, J; Bauloz, M; Maret-Fleuret, I; Borrocoso, S; Mercier, J; Brun, J F

2005-09-01

We assessed the effect of two programs combining a hypocaloric diet with low-intensity (LI) or high-intensity (HI) exercise training, during two months, on substrate utilization at exercise in obese children. Fifteen obese boys participated in a combined program of exercise and caloric restriction-induced weight loss (diet starting two weeks before the training program). The maximal fat oxidation point (Lipox max) was determined to individualize exercise training. Training consisted of cycling at either LI (Lipox max) for seven children or HI (Lipoxmax+40% Lipox max) for eight children. All children exhibited a decrease in weight (LI: -5.2 kg +/- 0.7 (P<0.01), HI: -7 kg +/- 0.7 (P<0.01)). While in the LI group, both fat and CHO oxidation were unchanged after training, HI group oxidize less fat and more CHO after training when exercising at 20% and 30% Wmax th (P = 0.02). While a LI exercise training program maintains (but does not improve) the ability to oxidize fat at exercise, HI training actually shifts towards CHO the balance of substrate oxidation during exercise. Thus, a low intensity training protocol seems to counteract to some extent the decline in lipid oxidation at exercise that occurs after a hypocaloric diet, and is thus likely to be synergistic to diet in the weight lowering strategy.

A single exercise bout and locomotor learning after stroke: physiological, behavioural, and computational outcomes.

PubMed

Charalambous, Charalambos C; Alcantara, Carolina C; French, Margaret A; Li, Xin; Matt, Kathleen S; Kim, Hyosub E; Morton, Susanne M; Reisman, Darcy S

2018-05-15

Previous work demonstrated an effect of a single high-intensity exercise bout coupled with motor practice on the retention of a newly acquired skilled arm movement, in both neurologically intact and impaired adults. In the present study, using behavioural and computational analyses we demonstrated that a single exercise bout, regardless of its intensity and timing, did not increase the retention of a novel locomotor task after stroke. Considering both present and previous work, we postulate that the benefits of exercise effect may depend on the type of motor learning (e.g. skill learning, sensorimotor adaptation) and/or task (e.g. arm accuracy-tracking task, walking). Acute high-intensity exercise coupled with motor practice improves the retention of motor learning in neurologically intact adults. However, whether exercise could improve the retention of locomotor learning after stroke is still unknown. Here, we investigated the effect of exercise intensity and timing on the retention of a novel locomotor learning task (i.e. split-belt treadmill walking) after stroke. Thirty-seven people post stroke participated in two sessions, 24 h apart, and were allocated to active control (CON), treadmill walking (TMW), or total body exercise on a cycle ergometer (TBE). In session 1, all groups exercised for a short bout (∼5 min) at low (CON) or high (TMW and TBE) intensity and before (CON and TMW) or after (TBE) the locomotor learning task. In both sessions, the locomotor learning task was to walk on a split-belt treadmill in a 2:1 speed ratio (100% and 50% fast-comfortable walking speed) for 15 min. To test the effect of exercise on 24 h retention, we applied behavioural and computational analyses. Behavioural data showed that neither high-intensity group showed greater 24 h retention compared to CON, and computational data showed that 24 h retention was attributable to a slow learning process for sensorimotor adaptation. Our findings demonstrated that acute exercise coupled with a locomotor adaptation task, regardless of its intensity and timing, does not improve retention of the novel locomotor task after stroke. We postulate that exercise effects on motor learning may be context specific (e.g. type of motor learning and/or task) and interact with the presence of genetic variant (BDNF Val66Met). © 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.

A comprehensive review of 46 exercise treatment studies in fibromyalgia (1988–2005)

PubMed Central

Jones, Kim Dupree; Adams, Dianne; Winters-Stone, Kerri; Burckhardt, Carol S

2006-01-01

The purpose of this review was to: (1) locate all exercise treatment studies of fibromyalgia (FM) patients from 1988 through 2005, (2) present in tabular format the key details of each study and (3) to provide a summary and evaluation of each study for exercise and health outcomes researchers. Exercise intervention studies in FM were retrieved through Cochrane Collaboration Reviews and key word searches of the medical literature, conference proceedings and bibliographies. Studies were reviewed for inclusion using a standardized process. A table summarizing subject characteristics, exercise mode, timing, duration, frequency, intensity, attrition and outcome variables was developed. Results, conclusions and comments were made for each study. Forty-six exercise treatment studies were found with a total of 3035 subjects. The strongest evidence was in support of aerobic exercise a treatment prescription for fitness and symptom and improvement. In general, the greatest effect and lowest attrition occurred in exercise programs that were of lower intensity than those of higher intensity. Exercise is a crucial part of treatment for people with FM. Increased health and fitness, along with symptom reduction, can be expected with exercise that is of appropriate intensity, self-modified, and symptom-limited. Exercise and health outcomes researchers are encouraged to use the extant literature to develop effective health enhancing programs for people with FM and to target research to as yet understudied FM subpopulations, such as children, men, older adults, ethnic minorities and those with common comorbidities of osteoarthritis and obesity. PMID:16999856

Mild aerobic exercise blocks elastin fiber fragmentation and aortic dilatation in a mouse model of Marfan syndrome associated aortic aneurysm.

PubMed

Gibson, Christine; Nielsen, Cory; Alex, Ramona; Cooper, Kimbal; Farney, Michael; Gaufin, Douglas; Cui, Jason Z; van Breemen, Cornelis; Broderick, Tom L; Vallejo-Elias, Johana; Esfandiarei, Mitra

2017-07-01

Regular low-impact physical activity is generally allowed in patients with Marfan syndrome, a connective tissue disorder caused by heterozygous mutations in the fibrillin-1 gene. However, being above average in height encourages young adults with this syndrome to engage in high-intensity contact sports, which unfortunately increases the risk for aortic aneurysm and rupture, the leading cause of death in Marfan syndrome. In this study, we investigated the effects of voluntary (cage-wheel) or forced (treadmill) aerobic exercise at different intensities on aortic function and structure in a mouse model of Marfan syndrome. Four-week-old Marfan and wild-type mice were subjected to voluntary and forced exercise regimens or sedentary lifestyle for 5 mo. Thoracic aortic tissue was isolated and subjected to structural and functional studies. Our data showed that exercise improved aortic wall structure and function in Marfan mice and that the beneficial effect was biphasic, with an optimum at low intensity exercise (55-65% V̇o 2max ) and tapering off at a higher intensity of exercise (85% V̇o 2max ). The mechanism underlying the reduced elastin fragmentation in Marfan mice involved reduction of the expression of matrix metalloproteinases 2 and 9 within the aortic wall. These findings present the first evidence of potential beneficial effects of mild exercise on the structural integrity of the aortic wall in Marfan syndrome associated aneurysm. Our finding that moderate, but not strenuous, exercise protects aortic structure and function in a mouse model of Marfan syndrome could have important implications for the medical care of young Marfan patients. NEW & NOTEWORTHY The present study provides conclusive scientific evidence that daily exercise can improve aortic health in a mouse model of Marfan syndrome associated aortic aneurysm, and it establishes the threshold for the exercise intensity beyond which exercise may not be as protective. These findings establish a platform for a new focus on promoting regular exercise in Marfan patients at an optimum intensity and create a paradigm shift in clinical care of Marfan patients suffering from aortic aneurysm complications. Copyright © 2017 the American Physiological Society.

Experiences of older people with dementia participating in a high-intensity functional exercise program in nursing homes: "While it's tough, it's useful"

PubMed Central

Lundin-Olsson, Lillemor; Skelton, Dawn A.; Lundman, Berit; Rosendahl, Erik

2017-01-01

The objective of the study was to describe the views and experiences of participation in a high-intensity functional exercise (HIFE) program among older people with dementia in nursing homes. The study design was a qualitative interview study with 21 participants (15 women), aged 74–96, and with a Mini-Mental State Examination score of 10–23 at study start. The HIFE-program comprises exercises performed in functional weight-bearing positions and including movements used in everyday tasks. The exercise was individually designed, supervised in small groups in the nursing homes and performed during four months. Interviews were performed directly after exercise sessions and field notes about the sessions were recorded. Qualitative content analysis was used for analyses. The analysis revealed four themes: Exercise is challenging but achievable; Exercise gives pleasure and strength; Exercise evokes body memories; and Togetherness gives comfort, joy, and encouragement. The intense and tailored exercise, adapted to each participant, was perceived as challenging but achievable, and gave pleasure and improvements in mental and bodily strength. Memories of previous physical activities aroused and participants rediscovered bodily capabilities. Importance of individualized and supervised exercise in small groups was emphasized and created feelings of encouragement, safety, and coherence. The findings from the interviews reinforces the positive meaning of intense exercise to older people with moderate to severe dementia in nursing homes. The participants were able to safely adhere to and understand the necessity of the exercise. Providers of exercise should consider the aspects valued by participants, e.g. supervision, individualization, small groups, encouragement, and that exercise involved joy and rediscovery of body competencies. PMID:29149198

Physiological parameter values in greyhounds before and after high-intensity exercise.

PubMed

Pellegrino, Francisco Javier; Risso, Analía; Vaquero, Pablo G; Corrada, Yanina A

2018-01-01

Dog sports competitions have greatly expanded. The availability of reference values for each type of activity could help assess fitness accurately. Heart rate (HR), blood lactate (BL) and rectal temperature (RT) are relevant physiological parameters to determine the dogs response to effort. Previous studies in greyhounds have reported the effect of high-intensity exercise on many physiological parameters immediately after completing different racing distances and recovery times. However, there are no studies concerning physiological changes over shorter racing distances. We therefore assessed the effect of sprint exercise on HR, BL and RT in nine greyhounds performing sprint exercise over a 100-m distance chasing a lure. After the exercise, dogs underwent a passive 10-min recovery phase. Before the exercise, immediately after it and at 5 and 10 min during recovery, HR and RT were assessed and blood samples were collected for BL determination. HR, BL and RT values increased significantly after the exercise (P<0.01). Whereas HR returned to pre-exercise values at 10 min during the recovery phase (P>0.1), BL concentration and RT remained increased (P<0.01). The abrupt increase in HR, BL and RT values observed immediately after the exercise indicates the high intensity of the effort performed. Similarly, BL concentration after the exercise exceeded the 4 mmol/L lactate threshold, suggesting a predominant anaerobic metabolism during effort. Although HR returned to pre-exercise values 10 min after the exercise, a more extensive recovery phase would be necessary for a total return to resting values, particularly for BL and RT. In greyhounds subjected to high-intensity exercise, HR, BL and RT were reliable physiological parameters to accurately assess the physiological response to effort. The use of sprint exercises over short racing distances could be useful for appropriately monitoring fitness in sporting dogs.

Experiences of older people with dementia participating in a high-intensity functional exercise program in nursing homes: "While it's tough, it's useful".

PubMed

Lindelöf, Nina; Lundin-Olsson, Lillemor; Skelton, Dawn A; Lundman, Berit; Rosendahl, Erik

2017-01-01

The objective of the study was to describe the views and experiences of participation in a high-intensity functional exercise (HIFE) program among older people with dementia in nursing homes. The study design was a qualitative interview study with 21 participants (15 women), aged 74-96, and with a Mini-Mental State Examination score of 10-23 at study start. The HIFE-program comprises exercises performed in functional weight-bearing positions and including movements used in everyday tasks. The exercise was individually designed, supervised in small groups in the nursing homes and performed during four months. Interviews were performed directly after exercise sessions and field notes about the sessions were recorded. Qualitative content analysis was used for analyses. The analysis revealed four themes: Exercise is challenging but achievable; Exercise gives pleasure and strength; Exercise evokes body memories; and Togetherness gives comfort, joy, and encouragement. The intense and tailored exercise, adapted to each participant, was perceived as challenging but achievable, and gave pleasure and improvements in mental and bodily strength. Memories of previous physical activities aroused and participants rediscovered bodily capabilities. Importance of individualized and supervised exercise in small groups was emphasized and created feelings of encouragement, safety, and coherence. The findings from the interviews reinforces the positive meaning of intense exercise to older people with moderate to severe dementia in nursing homes. The participants were able to safely adhere to and understand the necessity of the exercise. Providers of exercise should consider the aspects valued by participants, e.g. supervision, individualization, small groups, encouragement, and that exercise involved joy and rediscovery of body competencies.

The roles of the Na+/K+-ATPase, NKCC, and K+ channels in regulating local sweating and cutaneous blood flow during exercise in humans in vivo.

PubMed

Louie, Jeffrey C; Fujii, Naoto; Meade, Robert D; Kenny, Glen P

2016-11-01

Na + /K + -ATPase has been shown to regulate the sweating and cutaneous vascular responses during exercise; however, similar studies have not been conducted to assess the roles of the Na-K-2Cl co-transporter (NKCC) and K + channels. Additionally, it remains to be determined if these mechanisms underpinning the heat loss responses differ with exercise intensity. Eleven young (24 ± 4 years) males performed three 30-min semirecumbent cycling bouts at low (30% VO 2peak ), moderate (50% VO 2peak ), and high (70% VO 2peak ) intensity, respectively, each separated by 20-min recovery periods. Using intradermal microdialysis, four forearm skin sites were continuously perfused with either: (1) lactated Ringer solution (Control); (2) 6 mmol·L -1 ouabain (Na + /K + -ATPase inhibitor); (3) 10 mmol·L -1 bumetanide (NKCC inhibitor); or (4) 50 mmol·L -1 BaCl 2 (nonspecific K + channel inhibitor); sites at which we assessed local sweat rate (LSR) and cutaneous vascular conductance (CVC). Inhibition of Na + /K + -ATPase attenuated LSR compared to Control during the moderate and high-intensity exercise bouts (both P ˂ 0.01), whereas attenuations with NKCC and K + channel inhibition were only apparent during the high-intensity exercise bout (both P ≤ 0.05). Na + /K + -ATPase inhibition augmented CVC during all exercise intensities (all P ˂ 0.01), whereas CVC was greater with NKCC inhibition during the low-intensity exercise only (P ˂ 0.01) and attenuated with K + channel inhibition during the moderate and high-intensity exercise conditions (both P ˂ 0.01). We show that Na + /K + -ATPase, NKCC and K +  channels all contribute to the regulation of sweating and cutaneous blood flow but their influence is dependent on the intensity of dynamic exercise. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Design of the Resistance and Endurance exercise After ChemoTherapy (REACT) study: a randomized controlled trial to evaluate the effectiveness and cost-effectiveness of exercise interventions after chemotherapy on physical fitness and fatigue.

PubMed

Kampshoff, Caroline S; Buffart, Laurien M; Schep, Goof; van Mechelen, Willem; Brug, Johannes; Chinapaw, Mai J M

2010-11-30

Preliminary studies suggest that physical exercise interventions can improve physical fitness, fatigue and quality of life in cancer patients after completion of chemotherapy. Additional research is needed to rigorously test the effects of exercise programmes among cancer patients and to determine optimal training intensity accordingly. The present paper presents the design of a randomized controlled trial evaluating the effectiveness and cost-effectiveness of a high intensity exercise programme compared to a low-to-moderate intensity exercise programme and a waiting list control group on physical fitness and fatigue as primary outcomes. After baseline measurements, cancer patients who completed chemotherapy are randomly assigned to either a 12-week high intensity exercise programme or a low-to-moderate intensity exercise programme. Next, patients from both groups are randomly assigned to immediate training or a waiting list (i.e. waiting list control group). After 12 weeks, patients of the waiting list control group start with the exercise programme they have been allocated to.Both interventions consist of equal bouts of resistance and endurance interval exercises with the same frequency and duration, but differ in training intensity. Additionally, patients of both exercise programmes are counselled to improve compliance and achieve and maintain an active lifestyle, tailored to their individual preferences and capabilities.Measurements will be performed at baseline (t = 0), 12 weeks after randomization (t = 1), and 64 weeks after randomization (t = 2). The primary outcome measures are cardiorespiratory fitness and muscle strength assessed by means of objective performance indicators, and self-reported fatigue. Secondary outcome measures include health-related quality of life, self-reported physical activity, daily functioning, body composition, mood and sleep disturbances, and return to work. In addition, compliance and satisfaction with the interventions will be evaluated. Potential moderation by pre- and post-illness lifestyle, health and exercise-related attitudes, beliefs and motivation will also be assessed. Finally, the cost-effectiveness of both exercise interventions will be evaluated. This randomized controlled trial will be a rigorous test of effects of exercise programmes for cancer patients after chemotherapy, aiming to contribute to evidence-based practice in cancer rehabilitation programmes. This study is registered at the Netherlands Trial Register (NTR2153).

Dietary and performance assessment of elite soccer players during a period of intense training.

PubMed

Rico-Sanz, J; Frontera, W R; Molé, P A; Rivera, M A; Rivera-Brown, A; Meredith, C N

1998-09-01

This study examined the nutritional and performance status of elite soccer players during intense training. Eight male players (age 17+/-2 years) of the Puerto Rican Olympic Team recorded daily activities and food intake over 12 days. Daily energy expenditure was 3,833+/-571 (SD) kcal, and energy intake was 3,952+/-1,071 kcal, of which 53.2+/-6.2% (8.3 g x kg BW(-1)) was from carbohydrates (CHO), 32.4+/-4.0% from fat, and 14.4+/-2.3% from protein. With the exception of calcium, all micronutrients examined were in accordance with dietary guidelines. Body fat was 7.6+/-1.1% of body weight. Time to completion of three runs of the soccer-specific test was 37.65+/-0.62 s, and peak torques of the knee flexors and extensors at 60 degrees x s(-1) were 139+/-6 and 225+/-9 N x m, respectively. Players' absolute amounts of CHO seemed to be above the minimum recommended intake to maximize glycogen storage, but calcium intakes were below recommended. Their body fat was unremarkable, and they had a comparatively good capacity to endure repeated bouts of intense soccer-specific exercise and to exert force with their knee extensors and flexors.

Misremembering Past Affect Predicts Adolescents' Future Affective Experience During Exercise.

PubMed

Karnaze, Melissa M; Levine, Linda J; Schneider, Margaret

2017-09-01

Increasing physical activity among adolescents is a public health priority. Because people are motivated to engage in activities that make them feel good, this study examined predictors of adolescents' feelings during exercise. During the 1st semester of the school year, we assessed 6th-grade students' (N = 136) cognitive appraisals of the importance of exercise. Participants also reported their affect during a cardiovascular fitness test and recalled their affect during the fitness test later that semester. During the 2nd semester, the same participants rated their affect during a moderate-intensity exercise task. Affect reported during the moderate-intensity exercise task was predicted by cognitive appraisals of the importance of exercise and by misremembering affect during the fitness test as more positive than it actually was. This memory bias mediated the association between appraising exercise as important and experiencing a positive change in affect during the moderate-intensity exercise task. These findings highlight the roles of both cognitive appraisals and memory as factors that may influence affect during exercise. Future work should explore whether affect during exercise can be modified by targeting appraisals and memories related to exercise experiences.

Misremembering Past Affect Predicts Adolescents’ Future Affective Experience during Exercise

PubMed Central

Karnaze, Melissa M.; Levine, Linda J.; Schneider, Margaret

2018-01-01

Purpose Increasing physical activity among adolescents is a public health priority. Because people are motivated to engage in activities that make them feel good, this study examined predictors of adolescents’ feelings during exercise. Method During the first semester of the school year, we assessed sixth grade students’ (N = 136) cognitive appraisals of the importance of exercise. Participants also reported their affect during a cardiovascular fitness test, and recalled their affect during the fitness test later that semester. During the second semester, the same participants rated their affect during a moderate-intensity exercise task. Results Affect reported during the moderate-intensity exercise task was predicted by cognitive appraisals of the importance of exercise, and by misremembering affect during the fitness test as more positive than it actually was. This memory bias mediated the association between appraising exercise as important and experiencing a positive change in affect during the moderate-intensity exercise task. Conclusion These findings highlight the roles of both cognitive appraisals and memory as factors that may influence affect during exercise. Future work should explore whether affect during exercise can be modified by targeting appraisals and memories related to exercise experiences. PMID:28494196

Exercise training dose differentially alters muscle and heart capillary density and metabolic functions in an obese rat with metabolic syndrome.

PubMed

Machado, Marcus Vinicius; Vieira, Aline Bomfim; da Conceição, Fabiana Gomes; Nascimento, Alessandro Rodrigues; da Nóbrega, Antonio Claudio Lucas; Tibirica, Eduardo

2017-12-01

What is the central question of this study? Regular exercise is recommended as a non-pharmacological approach for the prevention and treatment of metabolic syndrome. However, the impact of different combinations of intensity, duration and frequency of exercise on metabolic syndrome and microvascular density has not been reported. What is the main finding and its importance? We provide evidence on the impact of aerobic exercise dose on metabolic and microvascular alterations in an experimental model of metabolic syndrome induced by high-fat diet. We found that the exercise frequency and duration were the main factors affecting anthropometric and metabolic parameters and microvascular density in the skeletal muscle. Exercise intensity was related only to microvascular density in the heart. We evaluated the effect of the frequency, duration and intensity of exercise training on metabolic parameters and structural capillary density in obese rats with metabolic syndrome. Wistar-Kyoto rats were fed either a standard commercial diet (CON) or a high-fat diet (HFD). Animals that received the HFD were randomly separated into either a sedentary (SED) group or eight different exercise groups that varied according to the frequency, duration and intensity of training. After 12 weeks of aerobic exercise training, the body composition, aerobic capacity, haemodynamic variables, metabolic parameters and capillary density in the heart and skeletal muscle were evaluated. All the exercise training groups showed reduced resting systolic blood pressure and heart rate and normalized fasting glucose. The minimal amount of exercise (90 min per week) produced little effect on metabolic syndrome parameters. A moderate amount of exercise (150 min per week) was required to reduce body weight and improve capillary density. However, only the high amount of exercise (300 min per week) significantly reduced the amount of body fat depots. The three-way ANOVA showed a main effect of exercise frequency and duration for the improvement of metabolic syndrome and capillary density in skeletal muscle. Exercise intensity was a main factor in reversing microvascular rarefaction in the heart. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Effects of exercise intensity on plasma concentrations of appetite-regulating hormones: Potential mechanisms.

PubMed

Hazell, Tom J; Islam, Hashim; Townsend, Logan K; Schmale, Matt S; Copeland, Jennifer L

2016-03-01

The physiological control of appetite regulation involves circulating hormones with orexigenic (appetite-stimulating) and anorexigenic (appetite-inhibiting) properties that induce alterations in energy intake via perceptions of hunger and satiety. As the effectiveness of exercise to induce weight loss is a controversial topic, there is considerable interest in the effect of exercise on the appetite-regulating hormones such as acylated ghrelin, peptide YY (PYY), glucagon-like peptide-1 (GLP-1), and pancreatic polypeptide (PP). Research to date suggests short-term appetite regulation following a single exercise session is likely affected by decreases in acylated ghrelin and increases in PYY, GLP-1, and PP. Further, this exercise-induced response may be intensity-dependent. In an effort to guide future research, it is important to consider how exercise alters the circulating concentrations of these appetite-regulating hormones. Potential mechanisms include blood redistribution, sympathetic nervous system activity, gastrointestinal motility, cytokine release, free fatty acid concentrations, lactate production, and changes in plasma glucose and insulin concentrations. This review of relevant research suggests blood redistribution during exercise may be important for suppressing ghrelin, while other mechanisms involving cytokine release, changes in plasma glucose and insulin concentrations, SNS activity, and muscle metabolism likely mediate changes in the anorexigenic signals PYY and GLP-1. Overall, changes in appetite-regulating hormones following acute exercise appear to be intensity-dependent, with increasing intensity leading to a greater suppression of orexigenic signals and greater stimulation of anorexigenic signals. However, there is less research on how exercise-induced responses in appetite-regulating hormones differ between sexes or different age groups. A better understanding of how exercise intensity and workload affect appetite across the sexes and life stages will be a powerful tool in developing more successful strategies for managing weight. Copyright © 2015 Elsevier Ltd. All rights reserved.

Recruitment of single muscle fibers during submaximal cycling exercise.

PubMed

Altenburg, T M; Degens, H; van Mechelen, W; Sargeant, A J; de Haan, A

2007-11-01

In literature, an inconsistency exists in the submaximal exercise intensity at which type II fibers are activated. In the present study, the recruitment of type I and II fibers was investigated from the very beginning and throughout a 45-min cycle exercise at 75% of the maximal oxygen uptake, which corresponded to 38% of the maximal dynamic muscle force. Biopsies of the vastus lateralis muscle were taken from six subjects at rest and during the exercise, two at each time point. From the first biopsy single fibers were isolated and characterized as type I and II, and phosphocreatine-to-creatine (PCr/Cr) ratios and periodic acid-Schiff (PAS) stain intensities were measured. Cross sections were cut from the second biopsy, individual fibers were characterized as type I and II, and PAS stain intensities were measured. A decline in PCr/Cr ratio and in PAS stain intensity was used as indication of fiber recruitment. Within 1 min of exercise both type I and, although to a lesser extent, type II fibers were recruited. Furthermore, the PCr/Cr ratio revealed that the same proportion of fibers was recruited during the whole 45 min of exercise, indicating a rather constant recruitment. The PAS staining, however, proved inadequate to fully demonstrate fiber recruitment even after 45 min of exercise. We conclude that during cycling exercise a greater proportion of type II fibers is recruited than previously reported for isometric contractions, probably because of the dynamic character of the exercise. Furthermore, the PCr/Cr ratio method is more sensitive in determining fiber activation than the PAS stain intensity method.

Recovery of damaged skeletal muscle in mdx mice through low-intensity endurance exercise.

PubMed

Frinchi, M; Macaluso, F; Licciardi, A; Perciavalle, V; Coco, M; Belluardo, N; Morici, G; Mudò, G

2014-01-01

The lack of dystrophin in mdx mice leads to cycles of muscle degeneration and regeneration processes. Various strategies have been proposed in order to reduce the muscle-wasting component of muscular dystrophy, including implementation of an exercise programme. The aim of this study was to examine how low-intensity endurance exercise affects the degeneration-regeneration process in dystrophic muscle of male mdx mice. Mice were subjected to low-intensity endurance exercise by running on a motorized Rota-Rod for 5 days/week for 6 weeks. Histomorphological analysis showed a significant reduction of measured inflammatory-necrotic areas in both gastrocnemius and quadriceps muscle of exercised mdx mice as compared to matched sedentary mdx mice. The degenerative-regenerative process was also evaluated by examining the protein levels of connexin 39 (Cx39), a specific gene expressed in injured muscles. Cx39 was not detected in sedentary wild type mice, whereas it was found markedly increased in sedentary mdx mice, revealing active muscle degeneration-regeneration process. These Cx39 protein levels were significantly reduced in muscles of mdx mice exercised for 30 and 40 days, revealing together with histomorphological analysis a strong reduction of degeneration process in mice subjected to low-intensity endurance exercise. Muscles of exercised mdx mice did not show significant changes in force and fatigue resistance as compared to sedentary mdx mice. Overall in this study we found that specific low-intensity endurance exercise induces a beneficial effect probably by reducing the degeneration of dystrophic muscle. © Georg Thieme Verlag KG Stuttgart · New York.

The effect of midday moderate-intensity exercise on postexercise hypoglycemia risk in individuals with type 1 diabetes.

PubMed

Davey, Raymond J; Howe, Warwick; Paramalingam, Nirubasini; Ferreira, Luis D; Davis, Elizabeth A; Fournier, Paul A; Jones, Timothy W

2013-07-01

Exercise increases the risk of hypoglycemia in type 1 diabetes. Recently we reported a biphasic increase in glucose requirements to maintain euglycemia after late-afternoon exercise, suggesting a unique pattern of delayed risk for nocturnal hypoglycemia. This study examined whether this pattern of glucose requirements occurs if exercise is performed earlier in the day. Ten adolescents with type 1 diabetes underwent a hyperinsulinemic euglycemic glucose clamp on 2 different occasions during which they either rested or performed 45 minutes of moderate-intensity exercise at midday. Glucose was infused to maintain euglycemia for 17 hours after exercise. The glucose infusion rate (GIR) to maintain euglycemia, glucose rates of appearance and disappearance, and levels of counterregulatory hormones were compared between conditions. GIRs to maintain euglycemia were not significantly different between groups at baseline (9.8 ± 1.4 and 9.5 ± 1.6 g/h before the exercise and rest conditions, respectively) and did not change in the rest condition throughout the study. In contrast, GIR increased more than 3-fold during exercise (from 9.8 ± 1.4 to 30.6 ± 4.7 g/h), fell within the first hour of recovery, but remained elevated until 11 hours after exercise before returning to baseline levels. The pattern of glucose requirements to maintain euglycemia in response to moderate-intensity exercise performed at midday suggests that the risk of exercise-mediated hypoglycemia increases during and for several hours after moderate-intensity exercise, with no evidence of a biphasic pattern of postexercise risk of hypoglycemia.

Calcineurin-NFAT Signaling and Neurotrophins Control Transformation of Myosin Heavy Chain Isoforms in Rat Soleus Muscle in Response to Aerobic Treadmill Training.

PubMed

Liu, Wenfeng; Chen, Gan; Li, Fanling; Tang, Changfa; Yin, Dazhong

2014-12-01

This study elucidated the role of CaN-NFAT signaling and neurotrophins on the transformation of myosin heavy chain isoforms in the rat soleus muscle fiber following aerobic exercise training. To do so, we examined the content and distribution of myosin heavy chain (MyHC) isoforms in the rat soleus muscle fiber, the activity of CaN and expression of NFATc1 in these fibers, and changes in the expression of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neutrophin-3 (NT-3) in the soleus and striatum following high-and medium-intensity aerobic treadmill training. Specific pathogen-free 2 month old male Sprague-Dawley (SD) rats were randomly divided into three groups: Control group (Con, n = 8), moderate-intensity aerobic exercise group (M-Ex, n = 8) and high-intensity aerobic exercise group (H-Ex, n = 8). We used ATPase staining to identify the muscle fiber type I and II, SDS-PAGE to separate and analyze the isoforms MyHCI, MyHCIIA, MyHCIIB and MyHCIIx, and performed western blots to determine the expression of NFATc1, NGF, BDNF and NT-3. CaN activity was measured using a colorimetric assay. In the soleus muscle, 8 weeks of moderate-intensity exercise can induce transformation of MyHC IIA and MyHC IIB to MyHC IIX and MyHC I (p < 0.01), while high-intensity treadmill exercise can induce transform MyHC IIx to MyHC IIB, MyHC IIA and MyHC I (p < 0.01). In comparison to the control group, CaN activity and NFATcl protein level were significantly increased in both the M-Ex and H-Ex groups (p < 0.05, p < 0.01), with a more pronounced upregulation in the M-Ex group (p < 0.05). Eight weeks of moderate- and high-intensity aerobic exercise induced the expression of NGF, BDNF and NT-3 in the soleus muscle and the striatum (p < 0.01), with the most significant increase in the H-Ex group (p < 0.01). In the rat soleus muscle, (1) CaN-NFATcl signaling contributes to the conversion of MyHC I isoform in response to moderate-intensity exercise; (2) Neurotrophins NGF, BDNF and NT-3 might play a role in the conversion of MyHC II isoform in response to high-intensity treadmill exercise. Key pointsEight weeks of moderate-intensity treadmill training induces the transformation MyHC IIA and MyHC IIB to MyHC IIX and MyHC I in the soleus muscles, while high-intensity exercise leads to transformation of MyHC IIX to MyHC IIA, MyHC IIB and MyHC I.MyHC I conversion in response to moderate-intensity aerobic exercise is mediated by calcineurin-NFATcl signaling.Eight weeks of moderate- and high-ntensity aerobic exercise induces the expression of NGF, BDNF and NT-3 in expression noted in rats subjected to high-intensity training. NGF and NT-3 expression in the striatum is lower than in the soleus muscle, while BDNF levels are similar. Neurotrophins may be involved in mediating MyHC II conversion in response to high-intensity aerobic exercise.

Dedicated cardiac rehabilitation wearable sensor and its clinical potential.

PubMed

Lee, Hooseok; Chung, Heewon; Ko, Hoon; Jeong, Changwon; Noh, Se-Eung; Kim, Chul; Lee, Jinseok

2017-01-01

We describe a wearable sensor developed for cardiac rehabilitation (CR) exercise. To effectively guide CR exercise, the dedicated CR wearable sensor (DCRW) automatically recommends the exercise intensity to the patient by comparing heart rate (HR) measured in real time with a predefined target heart rate zone (THZ) during exercise. The CR exercise includes three periods: pre-exercise, exercise with intensity guidance, and post-exercise. In the pre-exercise period, information such as THZ, exercise type, exercise stage order, and duration of each stage are set up through a smartphone application we developed for iPhones and Android devices. The set-up information is transmitted to the DCRW via Bluetooth communication. In the period of exercise with intensity guidance, the DCRW continuously estimates HR using a reflected pulse signal in the wrist. To achieve accurate HR measurements, we used multichannel photo sensors and increased the chances of acquiring a clean signal. Subsequently, we used singular value decomposition (SVD) for de-noising. For the median and variance of RMSEs in the measured HRs, our proposed method with DCRW provided lower values than those from a single channel-based method and template-based multiple-channel method for the entire exercise stage. In the post-exercise period, the DCRW transmits all the measured HR data to the smartphone application via Bluetooth communication, and the patient can monitor his/her own exercise history.

The Effect of an Acute Bout of Moderate-Intensity Aerobic Exercise on Motor Learning of a Continuous Tracking Task

PubMed Central

Snow, Nicholas J.; Mang, Cameron S.; Roig, Marc; Boyd, Lara A.

2016-01-01

Introduction There is evidence for beneficial effects of acute and long-term exercise interventions on several forms of memory, including procedural motor learning. In the present study we examined how performing a single bout of continuous moderate intensity aerobic exercise would impact motor skill acquisition and retention in young healthy adults, compared to a period of rest. We hypothesized that exercise would improve motor skill acquisition and retention, compared to motor practice alone. Materials and Methods Sixteen healthy adults completed sessions of aerobic exercise or seated rest that were immediately followed by practice of a novel motor task (practice). Exercise consisted of 30 minutes of continuous cycling at 60% peak O2 uptake. Twenty-four hours after practice, we assessed motor learning with a no-exercise retention test (retention). We also quantified changes in offline motor memory consolidation, which occurred between practice and retention (offline). Tracking error was separated into indices of temporal precision and spatial accuracy. Results There were no differences between conditions in the timing of movements during practice (p = 0.066), at retention (p = 0.761), or offline (p = 0.966). However, the exercise condition enabled participants to maintain spatial accuracy during practice (p = 0.477); whereas, following rest performance diminished (p = 0.050). There were no significant differences between conditions at retention (p = 0.532) or offline (p = 0.246). Discussion An acute bout of moderate-intensity aerobic exercise facilitated the maintenance of motor performance during skill acquisition, but did not influence motor learning. Given past work showing that pairing high intensity exercise with skilled motor practice benefits learning, it seems plausible that intensity is a key modulator of the effects of acute aerobic exercise on changes in complex motor behavior. Further work is necessary to establish a dose-response relationship between aerobic exercise and motor learning. PMID:26901664

Optimizing Cardiovascular Benefits of Exercise: A Review of Rodent Models

PubMed Central

Davis, Brittany; Moriguchi, Takeshi; Sumpio, Bauer

2013-01-01

Although research unanimously maintains that exercise can ward off cardiovascular disease (CVD), the optimal type, duration, intensity, and combination of forms are yet not clear. In our review of existing rodent-based studies on exercise and cardiovascular health, we attempt to find the optimal forms, intensities, and durations of exercise. Using Scopus and Medline, a literature review of English language comparative journal studies of cardiovascular benefits and exercise was performed. This review examines the existing literature on rodent models of aerobic, anaerobic, and power exercise and compares the benefits of various training forms, intensities, and durations. The rodent studies reviewed in this article correlate with reports on human subjects that suggest regular aerobic exercise can improve cardiac and vascular structure and function, as well as lipid profiles, and reduce the risk of CVD. Findings demonstrate an abundance of rodent-based aerobic studies, but a lack of anaerobic and power forms of exercise, as well as comparisons of these three components of exercise. Thus, further studies must be conducted to determine a truly optimal regimen for cardiovascular health. PMID:24436579

Absolutely relative or relatively absolute: violations of value invariance in human decision making.

PubMed

Teodorescu, Andrei R; Moran, Rani; Usher, Marius

2016-02-01

Making decisions based on relative rather than absolute information processing is tied to choice optimality via the accumulation of evidence differences and to canonical neural processing via accumulation of evidence ratios. These theoretical frameworks predict invariance of decision latencies to absolute intensities that maintain differences and ratios, respectively. While information about the absolute values of the choice alternatives is not necessary for choosing the best alternative, it may nevertheless hold valuable information about the context of the decision. To test the sensitivity of human decision making to absolute values, we manipulated the intensities of brightness stimuli pairs while preserving either their differences or their ratios. Although asked to choose the brighter alternative relative to the other, participants responded faster to higher absolute values. Thus, our results provide empirical evidence for human sensitivity to task irrelevant absolute values indicating a hard-wired mechanism that precedes executive control. Computational investigations of several modelling architectures reveal two alternative accounts for this phenomenon, which combine absolute and relative processing. One account involves accumulation of differences with activation dependent processing noise and the other emerges from accumulation of absolute values subject to the temporal dynamics of lateral inhibition. The potential adaptive role of such choice mechanisms is discussed.

Benefits of different intensity of aerobic exercise in modulating body composition among obese young adults: a pilot randomized controlled trial.

PubMed

Chiu, Chih-Hui; Ko, Ming-Chen; Wu, Long-Shan; Yeh, Ding-Peng; Kan, Nai-Wen; Lee, Po-Fu; Hsieh, Jenn-Woei; Tseng, Ching-Yu; Ho, Chien-Chang

2017-08-24

The aim of present study was to compare the effects of different aerobic exercise intensities and energy expenditures on the body composition of sedentary obese college students in Taiwan. Forty-eight obese participants [body mass index (BMI) ≥ 27 kg/m 2 , age 18-26 years] were randomized into four equal groups (n = 12): light-intensity training group (LITG), 40%-50% heart rate reserve (HRR); middle-intensity training group (MITG), 50%-70% HRR; high-intensity training group (HITG), 70%-80% HRR; and control group (CG). The aerobic exercise training program was conducted for 60 min per day on a treadmill 3 days per week for 12 weeks. All participant anthropometric data, blood biochemical parameters, and health-related physical fitness components were measured at baseline and after 12 weeks. At baseline, the anthropometric indices did not differ significantly among the four groups (p > 0.05). After 12-week exercise intervention, the HITG and MITG had significantly more changes in body weight, waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) than the LITG. The changes in BMI and body fat percentage differed among all four groups (p < 0.05). A 12-week high-intensity exercise intervention with high energy expenditure can considerably reduce body weight, body fat, WC, WHR, and WHtR, whereas a light-intensity exercise intervention can significantly reduce body weight and body fat. Current Controlled Trials TPECTR09831410900 , registered on 24 th Dec 2009.

Maximal Fat Oxidation Rates in an Athletic Population.

PubMed

Randell, Rebecca K; Rollo, Ian; Roberts, Timothy J; Dalrymple, Kortney J; Jeukendrup, Asker E; Carter, James M

2017-01-01

The aim of this study was to describe maximal fat oxidation (MFO) rates in an athletic population. In total, 1121 athletes (933 males and 188 females), from a variety of sports and competitive level, undertook a graded exercise test on a treadmill in a fasted state (≥5 h fasted). Rates of fat oxidation were determined using indirect calorimetry. The average MFO was 0.59 ± 0.18 g·min, ranging from 0.17 to 1.27 g·min. Maximal rates occurred at an average exercise intensity of 49.3% ± 14.8% V˙O2max, ranging from 22.6% to 88.8% V˙O2max. In absolute terms, male athletes had significantly higher MFO compared with females (0.61 and 0.50 g·min, respectively, P < 0.001). Expressed relative to fat-free mass (FFM), MFO were higher in the females compared with males (MFO/FFM: 11.0 and 10.0 mg·kg·FFM·min, respectively, P < 0.001). Soccer players had the highest MFO/FFM (10.8 mg·kg·FFM·min), ranging from 4.1 to 20.5 mg·kg·FFM·min, whereas American Football players displayed the lowest rates of MFO/FFM (9.2 mg·kg·FFM·min). In all athletes, and when separated by sport, large individual variations in MFO rates were observed. Significant positive correlations were found between MFO (g·min) and the following variables: FFM, V˙O2max, FATMAX (the exercise intensity at which the MFO was observed), percent body fat, and duration of fasting. When taken together these variables account for 47% of the variation in MFO. MFO and FATMAX vary significantly between athletes participating in different sports but also in the same sport. Although variance in MFO can be explained to some extent by body composition and fitness status, more than 50% of the variance is not explained by these variables and remains unaccounted for.

Book Analysis of Arms and Insecurity in the Persian Gulf.

DTIC Science & Technology

1988-04-01

AND P. Exercise induced changes in blood ammonia levels in humans. Eur. VANAmEE. Respiratory alkalosis accompanying ammonia toxicity. J. AppL PhysioL...HA. to ensure uniform exercise intensity. Respiratory gas exchange and ventilation during ex- Submaximal Exercise ercise were measured using a...BTPS, 02 consumption (Vo 2) and CO2 group. Relative exercise intensity (%Vo, mx) was not production converted to STPD, and respiratory exchange

A 10-s sprint performed prior to moderate-intensity exercise prevents early post-exercise fall in glycaemia in individuals with type 1 diabetes.

PubMed

Bussau, V A; Ferreira, L D; Jones, T W; Fournier, P A

2007-09-01

We investigated whether a 10-s maximal sprint effort performed immediately prior to moderate-intensity exercise provides another means to counter the rapid fall in glycaemia associated with moderate-intensity exercise in individuals with type 1 diabetes. Seven complication-free type 1 diabetic males (21.6 +/- 3.6 years; mean+/-SD) with HbA(1c) levels of 7.4 +/- 0.7% injected their normal morning insulin dose and ate their usual breakfast. When post-meal glycaemia fell to approximately 11 mmol/l, participants were asked to perform a 10-s all-out sprint (sprint trial) or to rest (control trial) immediately before cycling at 40% of peak rate of oxygen consumption for 20 min, with both trials conducted in a random counterbalanced order. Sprinting did not affect the rapid fall in glycaemia during the subsequent bout of moderate-intensity exercise (2.9 +/- 0.4 mmol/l in 20 min; p = 0.00; mean+/-SE). However, during the following 45 min of recovery, glycaemia in the control trial decreased by 1.23 +/- 0.60 mmol/l (p = 0.04) while remaining stable in the sprint trial, subsequently decreasing in this latter trial at a rate similar to that in the control trial. The large increase in noradrenaline (norepinephrine) (p = 0.005) and lactate levels (p = 0.0005) may have contributed to the early post-exercise stabilisation of glycaemia in the sprint trial. During recovery, adrenaline (epinephrine) and NEFA levels increased marginally in the sprint trial, but other counter-regulatory hormones did not change significantly (p < 0.05). A 10-s sprint performed immediately prior to moderate-intensity exercise prevents glycaemia from falling during early recovery from moderate-intensity exercise in individuals with type 1 diabetes.

Potassium kinetics in human muscle interstitium during repeated intense exercise in relation to fatigue.

PubMed

Mohr, Magni; Nordsborg, Nikolai; Nielsen, Jens Jung; Pedersen, Lasse Danneman; Fischer, Christian; Krustrup, Peter; Bangsbo, Jens

2004-07-01

Accumulation of K+ in skeletal muscle interstitium during intense exercise has been suggested to cause fatigue in humans. The present study examined interstitial K+ kinetics and fatigue during repeated, intense, exhaustive exercise in human skeletal muscle. Ten subjects performed three repeated, intense (61.6+/-4.1 W; mean+/-SEM), one-legged knee extension exercise bouts (EX1, EX2 and EX3) to exhaustion separated by 10-min recovery periods. Interstitial [K+] ([K+]interst) in the vastus lateralis muscle were determined using microdialysis. Time-to-fatigue decreased progressively (P<0.05) during the protocol (5.1+/-0.4, 4.2+/-0.3 and 3.2+/-0.2 min for EX1, EX2 and EX3 respectively). Prior to these bouts, [K+]interst was 4.1+/-0.2, 4.8+/-0.2 and 5.2+/-0.2 mM, respectively. During the initial 1.5 min of exercise the accumulation rate of interstitial K+ was 85% greater (P<0.05) in EX1 than in EX3. At exhaustion [K+]interst was 11.4+/-0.8 mM in EX1, which was not different from that in EX2 (10.4+/-0.8 mM), but higher (P<0.05) than in EX3 (9.1+/-0.3 mM). The study demonstrated that the rate of accumulation of K+ in the muscle interstitium declines during intense repetitive exercise. Furthermore, whilst [K+]interst at exhaustion reached levels high enough to impair performance, the concentration decreased with repeated exercise, suggesting that accumulation of interstitial K+ per se does not cause fatigue when intense exercise is repeated.

Acute high-intensity endurance exercise is more effective than moderate-intensity exercise for attenuation of postprandial triglyceride elevation.

PubMed

Trombold, Justin R; Christmas, Kevin M; Machin, Daniel R; Kim, Il-Young; Coyle, Edward F

2013-03-15

Acute exercise has been shown to attenuate postprandial plasma triglyceride elevation (PPTG). However, the direct contribution of exercise intensity is less well understood. The purpose of this study was to examine the effects of exercise intensity on PPTG and postprandial fat oxidation. One of three experimental treatments was performed in healthy young men (n = 6): nonexercise control (CON), moderate-intensity exercise (MIE; 50% Vo2peak for 60 min), or isoenergetic high-intensity exercise (HIE; alternating 2 min at 25% and 2 min at 90% Vo2peak). The morning after the exercise, a standardized meal was provided (16 kcal/kg BM, 1.02 g fat/kg, 1.36 g CHO/kg, 0.31 g PRO/kg), and measurements of plasma concentrations of triglyceride (TG), glucose, insulin, and β-hydroxybutyrate were made in the fasted condition and hourly for 6 h postprandial. Indirect calorimetry was used to determine fat oxidation in the fasted condition and 2, 4, and 6 h postprandial. Compared with CON, both MIE and HIE significantly attenuated PPTG [incremental AUC; 75.2 (15.5%), P = 0.033, and 54.9 (13.5%), P = 0.001], with HIE also significantly lower than MIE (P = 0.03). Postprandial fat oxidation was significantly higher in MIE [83.3 (10.6%) of total energy expenditure] and HIE [89.1 (9.8) %total] compared with CON [69.0 (16.1) %total, P = 0.039, and P = 0.018, respectively], with HIE significantly greater than MIE (P = 0.012). We conclude that, despite similar energy expenditure, HIE was more effective than MIE for lowering PPTG and increasing postprandial fat oxidation.

Exercise Therapy for Management of Type 2 Diabetes Mellitus: Superior Efficacy of Activity Monitors over Pedometers.

PubMed

Miyauchi, Masaaki; Toyoda, Masao; Kaneyama, Noriko; Miyatake, Han; Tanaka, Eitaro; Kimura, Moritsugu; Umezono, Tomoya; Fukagawa, Masafumi

2016-01-01

We compared the efficacy of activity monitor (which displays exercise intensity and number of steps) versus that of pedometer in exercise therapy for patients with type 2 diabetes. The study subjects were divided into the activity monitor group ( n = 92) and pedometer group ( n = 95). The primary goal was improvement in hemoglobin A1c (HbA1c). The exercise target was set at 8,000 steps/day and 20 minutes of moderate-intensity exercise (≥3.5 metabolic equivalents). The activity monitor is equipped with a triple-axis accelerometer sensor capable of measuring medium-intensity walking duration, number of steps, walking distance, calorie consumption, and total calorie consumption. The pedometer counts the number of steps. Blood samples for laboratory tests were obtained during the visits. The first examination was conducted at the start of the study and repeated at 2 and 6 months. A significant difference in the decrease in HbA1c level was observed between the two groups at 2 months. The results suggest that the use of activity level monitor that displays information on exercise intensity, in addition to the number of steps, is useful in exercise therapy as it enhances the concept of exercise therapy and promotes lowering of HbA1c in diabetic patients.

Acute post-exercise energy and macronutrient intake in lean and obese youth: a systematic review and meta-analysis.

PubMed

Thivel, D; Rumbold, P L; King, N A; Pereira, B; Blundell, J E; Mathieu, M-E

2016-10-01

This review aims to determine if acute exercise affects subsequent energy and macronutrients intake in obese and non-obese children and adolescents. Databases were searched between January 2015 and December 2015 for studies reporting energy and/or macronutrients intake immediately after an acute exercise and control condition, in children and adolescents. From the initial 118 references found, 14 were included for subsequent analysis after screening representing 31 acute exercise conditions that varied in intensity, duration and modality. One study found increased energy intake after exercise, seven decreased and 23 revealed no change. The meta-analysis revealed a significant effect of acute exercise on intake in obese but not in lean youth by a mean difference of -0.430 (95% confidence interval=-0.703 to -0.157, P=0.002) displaying low heterogeneity (I 2 =0.000; Q=5.875; d f =9, P=0.752). The analysis showed that intense exercise only reduces intake in obese children (no intensity effect in lean). Unchanged macronutrients intake was reported in nine studies as opposed to three which found modified lipids, protein and/or carbohydrate intake. Although acute exercise does not affect energy intake in lean, it appears to reduced food intake in obese youth when intense, without altering the macronutrients composition of the meal.

Association of von Willebrand factor blood levels with exercise hypertension.

PubMed

Nikolic, Sonja B; Adams, Murray J; Otahal, Petr; Edwards, Lindsay M; Sharman, James E

2015-05-01

A hypertensive response to moderate intensity exercise (HRE) is associated with increased cardiovascular risk. The mechanisms of an HRE are unclear, although previous studies suggest this may be due to haemostatic and/or haemodynamic factors. We investigated the relationships between an HRE with haemostatic and hemodynamic indices. Sixty-four participants (57 ± 10 years, 71 % male) with indication for exercise stress testing underwent cardiovascular assessment at rest and during moderate intensity exercise, from which 20 participants developed an HRE (defined as moderate exercise systolic BP ≥ 170 mmHg/men and ≥ 160 mmHg/women). Rest, exercise and post-exercise blood samples were analysed for haemostatic markers, including von Willebrand factor (vWf), and haemodynamic measures of brachial and central blood pressure (BP), aortic stiffness and systemic vascular resistance index (SVRi). HRE participants had higher rest vWf compared with normotensive response to exercise (NRE) participants (1,927 mU/mL, 95 % CI 1,240-2,615, vs. 1,129 mU/mL, 95 % CI 871-1,386; p = 0.016). vWf levels significantly decreased from rest to post-exercise in HRE participants (p = 0.005), whereas vWf levels significantly increased from rest to exercise in NRE participants (p = 0.030). HRE participants also had increased triglycerides, rest BP, aortic stiffness and exercise SVRi (p < 0.05 for all). Rest vWf predicted exercise brachial systolic BP (β = 0.220, p = 0.043; adjusted R (2) = 0.451, p < 0.001) independent of age, sex, body mass index, triglycerides, rest brachial systolic BP and aortic stiffness. Increased rest blood levels of vWf are independently associated with moderate intensity exercise systolic BP. These findings implicate abnormalities in haemostasis as a possible factor contributing to HRE at moderate intensity.

The effects of exercise intensity and post-exercise recovery time on cortical activation as revealed by EEG alpha peak frequency.

PubMed

Gutmann, B; Zimmer, P; Hülsdünker, T; Lefebvre, J; Binnebößel, S; Oberste, M; Bloch, W; Strüder, H K; Mierau, A

2018-03-06

Acute physical exercise (APE) induces an increase in the individual alpha peak frequency (iAPF), a cortical parameter associated with neural information processing speed. The aim of this study was to further scrutinize the influence of different APE intensities on post-exercise iAPF as well as its time course after exercise cessation. 95 healthy young (18-35 years) subjects participated in two randomized controlled experiments (EX1 and EX2). In EX1, all participants completed a graded exercise test (GXT) until exhaustion and were randomly allocated into different delay groups (immediately 0, 30, 60 and 90 min after GXT). The iAPF was determined before, immediately after as well as after the group-specific delay following the GXT. In EX2, participants exercised for 35 min at either 45-50%, 65-70% or 85-90% of their maximum heart rate (HR max ). The iAPF was determined before, immediately after as well as 20 min after exercise cessation. In EX1, the iAPF was significantly increased immediately after the GXT in all groups. This effect was not any more detectable after 30 min following exercise cessation. In EX2, a significant increase of the iAPF was found only after high-intensity (85-90% HR max ) exercise. The results indicate intense or exhaustive physical exercise is required to induce a transient increase in the iAPF that persists about 30 min following exercise cessation. Based on these findings, further research will have to scrutinize the behavioral implications associated with iAPF modulations following exercise. Copyright © 2018. Published by Elsevier B.V.

Kinetic quantification of plyometric exercise intensity.

PubMed

Ebben, William P; Fauth, McKenzie L; Garceau, Luke R; Petushek, Erich J

2011-12-01

Ebben, WP, Fauth, ML, Garceau, LR, and Petushek, EJ. Kinetic quantification of plyometric exercise intensity. J Strength Cond Res 25(12): 3288-3298, 2011-Quantification of plyometric exercise intensity is necessary to understand the characteristics of these exercises and the proper progression of this mode of exercise. The purpose of this study was to assess the kinetic characteristics of a variety of plyometric exercises. This study also sought to assess gender differences in these variables. Twenty-six men and 23 women with previous experience in performing plyometric training served as subjects. The subjects performed a variety of plyometric exercises including line hops, 15.24-cm cone hops, squat jumps, tuck jumps, countermovement jumps (CMJs), loaded CMJs equal to 30% of 1 repetition maximum squat, depth jumps normalized to the subject's jump height (JH), and single leg jumps. All plyometric exercises were assessed with a force platform. Outcome variables associated with the takeoff, airborne, and landing phase of each plyometric exercise were evaluated. These variables included the peak vertical ground reaction force (GRF) during takeoff, the time to takeoff, flight time, JH, peak power, landing rate of force development, and peak vertical GRF during landing. A 2-way mixed analysis of variance with repeated measures for plyometric exercise type demonstrated main effects for exercise type and all outcome variables (p ≤ 0.05) and for the interaction between gender and peak vertical GRF during takeoff (p ≤ 0.05). Bonferroni-adjusted pairwise comparisons identified a number of differences between the plyometric exercises for the outcome variables assessed (p ≤ 0.05). These findings can be used to guide the progression of plyometric training by incorporating exercises of increasing intensity over the course of a program.

An exploratory analysis of changes in mood, anxiety and craving from pre- to post-single sessions of exercise, over 12 weeks, among patients with alcohol dependence.

PubMed

Brown, Richard A; Prince, Mark A; Minami, Haruka; Abrantes, Ana M

2016-10-01

Aerobic exercise is currently being studied as a relapse prevention strategy for individuals with alcohol use disorders. Negative affect and cravings predict relapse. The acute effects of moderate-intensity exercise have been shown to improve mood and reduce craving. The current study examined the acute effects of exercise on changes in mood, anxiety, and craving from pre- to post-exercise at each week of a 12-week moderate intensity exercise intervention with sedentary alcohol dependent adults. Twenty-six participants in the exercise condition of a larger randomized clinical trial (Brown et al., 2014) exercised in small groups at moderate intensity for 20 to 40 minutes per session. Participants rated mood, anxiety, and cravings in the present moment before and after each exercise session over the course of the 12-week intervention. Data analyses focused on effect size and interval estimation. Joinpoint analysis was used to model longitudinal trends. Increases in mood and decreases in anxiety and craving were apparent at every session. Effect size estimates revealed that average change from pre- to post-exercise was in the small to medium range with some individual sessions reaching the large range. Joinpoint analyses revealed that the pre-post exercise changes in mood increased, anxiety remained stable, and craving diminished across the 12 weeks. This study provides provisional support for a change in mood, anxiety and alcohol cravings for the role of exercise in the early recovery period for alcohol dependence. Acute single bouts of moderate-intensity exercise may help individuals with alcohol dependence manage mood, anxiety, and craving thereby reducing relapse risk, but further research is needed with a more rigorous study design.

The effects of aerobic exercise for persons with migraine and co-existing tension-type headache and neck pain. A randomized, controlled, clinical trial.

PubMed

Krøll, Lotte Skytte; Hammarlund, Catharina Sjödahl; Linde, Mattias; Gard, Gunvor; Jensen, Rigmor Højland

2018-01-01

Aim To evaluate aerobic exercise in migraine and co-existing tension-type headache and neck pain. Methods Consecutively recruited persons with migraine and co-existing tension-type headache and neck pain were randomized into an exercise group or control group. Aerobic exercise consisted of bike/cross-trainer/brisk walking for 45 minutes, three times/week. Controls continued usual daily activities. Pain frequency, intensity, and duration; physical fitness, level of physical activity, well-being and ability to engage in daily activities were assessed at baseline, after treatment and at follow-up. Results Fifty-two persons completed the study. Significant between-group improvements for the exercise group were found for physical fitness, level of physical activity, migraine burden and the ability to engage in physical activity because of reduced impact of tension-type headache and neck pain. Within the exercise group, significant reduction was found for migraine frequency, pain intensity and duration, neck pain intensity, and burden of migraine; an increase in physical fitness and well-being. Conclusions Exercise significantly reduced the burden of migraine and the ability to engage in physical activity because of reduced impact of tension-type headache and neck pain. Exercise also reduced migraine frequency, pain intensity and duration, although this was not significant compared to controls. These results emphasize the importance of regular aerobic exercise for reduction of migraine burden.

Plasma ghrelin levels during exercise - effects of intensity and duration.

PubMed

Erdmann, Johannes; Tahbaz, Rana; Lippl, Florian; Wagenpfeil, Stefan; Schusdziarra, Volker

2007-10-04

Ghrelin, a recently discovered hormone of gastric origin has been shown to stimulate appetite and food intake. In man it is considered to play a role in energy homeostasis and regulation of somatropic function. As exercise affects hunger/satiety sensations and food intake, at least under some experimental conditions, we investigated the effect of exercise intensity and duration on ghrelin release and subsequent ad libitum food intake in normal weight subjects. Bicycle exercise on an ergometer for 30 min at 50 W which was below the aerob-anaerobic threshold led to an increase of ghrelin which remained unchanged during the higher intensity at 100 W. Respective hunger/satiety ratings and subsequent food intake and postprandial ghrelin suppression were identical and not different from controls. In a second group 7 subjects cycled at 50 W for 30, 60 and 120 min, respectively. Ghrelin concentrations rose significantly by 50-70 pg/ml above baseline for the respective period of exercise. While postexercise premeal ghrelin levels were not significantly different subsequent food intake after 120 min of cycling was significantly greater compared to control, 30 min and 60 min exercise, respectively. The present data suggest that low rather than high-intensity exercise stimulates ghrelin levels independent of exercise duration. Stimulation of food intake during prolonged exercise is most likely not due to changes of ghrelin.

Moderate intensity sports and exercise is associated with glycaemic control in women with gestational diabetes.

PubMed

Ehrlich, S F; Hedderson, M M; Brown, S D; Sternfeld, B; Chasan-Taber, L; Feng, J; Adams, J; Ching, J; Crites, Y; Quesenberry, C P; Ferrara, A

2017-10-01

To assess the association of regular, unsupervised sports and exercise during pregnancy, by intensity level, with glycaemic control in women with gestational diabetes (GDM). Prospective cohort study of 971 women who, shortly after being diagnosed with GDM, completed a Pregnancy Physical Activity Questionnaire assessing moderate and vigorous intensity sports and exercise in the past 3 months. Self-monitored capillary glucose values were obtained for the 6-week period following the questionnaire, with optimal glycaemic control defined≥80% values meeting the targets<5.3mmol/L for fasting and <7.8mmol/L 1-hour after meals. Logistic regression estimated the odds of achieving optimal control; linear regression estimated activity level-specific least square mean glucose, as well as between-level mean glucose differences. For volume of moderate intensity sports and exercise ([MET×hours]/week), the highest quartile, compared to the lowest, had significantly increased odds of optimal control (OR=1.82 [95% CI: 1.06-3.14] P=0.03). There were significant trends for decreasing mean 1-hour post breakfast, lunch and dinner glycaemia with increasing quartile of moderate activity (all P<0.05). Any participation in vigorous intensity sports and exercise was associated with decreased mean 1-hour post breakfast and lunch glycaemia (both P<0.05). No associations were observed for fasting. Higher volumes of moderate intensity sports and exercise, reported shortly after GDM diagnosis, were significantly associated with increased odds of achieving glycaemic control. Clinicians should be aware that unsupervised moderate intensity sports and exercise performed in mid-pregnancy aids in subsequent glycaemic control among women with GDM. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

A multisession evaluation of an adaptive competitive arm rehabilitation game.

PubMed

Goršič, Maja; Cikajlo, Imre; Goljar, Nika; Novak, Domen

2017-12-06

People with neurological injuries such as stroke should exercise frequently and intensely to regain their motor abilities, but are generally hindered by lack of motivation. One way to increase motivation in rehabilitation is through competitive exercises, but such exercises have only been tested in single brief sessions and usually did not adapt difficulty to the patient's abilities. We designed a competitive arm rehabilitation game for two players that dynamically adapts its difficulty to both players' abilities. This game was evaluated by two participant groups: 15 participants with chronic arm impairment who exercised at home with an unimpaired friend or relative, and 20 participants in the acute or subacute phase of stroke who exercised in pairs (10 pairs) at a rehabilitation clinic. All participants first played the game against their human opponent for 3 sessions, then played alone (against a computer opponent) in the final, fourth session. In all sessions, participants' subjective experiences were assessed with the Intrinsic Motivation Inventory questionnaire while exercise intensity was measured using inertial sensors built into the rehabilitation device. After the fourth session, a final brief questionnaire was used to compare competition and exercising alone. Participants who played against an unimpaired friend or relative at home tended to prefer competition (only 1 preferred exercising alone), and exhibited higher enjoyment and exercise intensity when competing (first three sessions) than when exercising alone (last session). Participants who played against each other in the clinic, however, did not exhibit significant differences between competition and exercising alone. For both groups, there was no difference in enjoyment or exercise intensity between the first three sessions, indicating no negative effects of habituation or novelty. Competitive exercises have high potential for unsupervised home rehabilitation, as they improve enjoyment and exercise intensity compared to exercising alone. Such exercises could thus improve rehabilitation outcome, but this needs to be tested in long-term clinical trials. It is not clear why participants who competed against each other at the clinic did not exhibit any advantages of competition, and further studies are needed to determine how different factors (environment, nature of opponent etc.) influence patients' experiences with competitive exercises. The study is not a clinical trial. While human subjects are involved, they do not participate in a full rehabilitation intervention, and no health outcomes are examined.

Relationship between traditional and ballistic squat exercise with vertical jumping and maximal sprinting.

PubMed

Requena, Bernardo; García, Inmaculada; Requena, Francisco; de Villarreal, Eduardo Sáez-Sáez; Cronin, John B

2011-08-01

The purpose of this study was to quantify the magnitude of the relationship between vertical jumping and maximal sprinting at different distances with performance in the traditional and ballistic concentric squat exercise in well-trained sprinters. Twenty-one men performed 2 types of barbell squats (ballistic and traditional) across different loads with the aim of determining the maximal peak and average power outputs and 1 repetition maximum (1RM) values. Moreover, vertical jumping (countermovement jump test [CMJ]) and maximal sprints over 10, 20, 30, 40, 60, and 80 m were also assessed. In respect to 1RM in traditional squat, (a) no significant correlation was found with CMJ performance; (b) positive strong relationships (p < 0.01) were obtained with all the power measures obtained during both ballistic and traditional squat exercises (r = 0.53-0.90); (c) negative significant correlations (r = -0.49 to -0.59, p < 0.05) were found with sprint times in all the sprint distances measured when squat strength was expressed as a relative value; however, in the absolute mode, no significant relationships were observed with 10- and 20-m sprint times. No significant relationship was found between 10-m sprint time and relative or absolute power outputs using either ballistic or traditional squat exercises. Sprint time at 20 m was only related to ballistic and traditional squat performance when power values were expressed in relative terms. Moderate significant correlations (r = -0.39 to -0.56, p < 0.05) were observed between sprint times at 30 and 40 m and the absolute/relative power measures attained in both ballistic and traditional squat exercises. Sprint times at 60 and 80 m were mainly related to ballistic squat power outputs. Although correlations can only give insights into associations and not into cause and effect, from this investigation, it can be seen that traditional squat strength has little in common with CMJ performance and that relative 1RM and power outputs for both squat exercises are statistically correlated to most sprint distances underlying the importance of strength and power to sprinting.

Potential Universal Application of High-intensity Interval Training from Athletes and Sports Lovers to Patients.

PubMed

Azuma, Koichiro; Matsumoto, Hideo

2017-06-25

Recently, high-intensity interval training (HIIT) has received much attention as a promising exercise option not only to improve aerobic fitness, but also to prevent and improve lifestyle-related diseases. Epidemiological studies have shown that the exercise volume, as determined by the product of exercise intensity, duration, and frequency, has been shown to be important for improvements in muscle mitochondrial activity and subsequent improvements in aerobic fitness, insulin sensitivity, and metabolic variables. Therefore, continuous moderate-intensity training has been widely recommended. On the other hand, the main contributor of HIIT to improvements in aerobic fitness and metabolic variables is its high-intensity nature, and many recent studies have shown results favoring HIIT when compared with conventional continuous training, despite its shorter exercise duration and smaller exercise volume. In this review, we aim to show the possible universal application of HIIT in a hospital setting, where athletes, sports lovers, and patients have sought medical advice and have the opportunity to undergo detailed evaluations, including an exercise stress test. For athletes, HIIT is mandatory to achieve further improvements in aerobic fitness. For patients, though higher levels of motivation and careful evaluation are required, the time constraints of HIIT are smaller and both aerobic and resistance training can be expected to yield favorable results because of the high-intensity nature of HIIT.

Anterior cerebral blood velocity and end-tidal CO2 responses to exercise differ in children and adults.

PubMed

Ellis, Lindsay A; Ainslie, Philip N; Armstrong, Victoria A; Morris, Laura E; Simair, Ryan G; Sletten, Nathan R; Tallon, Christine M; McManus, Ali M

2017-06-01

Little is known about the response of the cerebrovasculature to acute exercise in children and how these responses might differ with adults. Therefore, we compared changes in middle cerebral artery blood velocity (MCAV mean ), end-tidal Pco 2 ([Formula: see text]), blood pressure, and minute ventilation (V̇e) in response to incremental exercise between children and adults. Thirteen children [age: 9 ± 1 (SD) yr] and thirteen sex-matched adults (age: 25 ± 4 yr) completed a maximal exercise test, during which MCAV mean , [Formula: see text], and V̇e were measured continuously. These variables were measured at rest, at exercise intensities specific to individual ventilatory thresholds, and at maximum. Although MCAV mean was higher at rest in children compared with adults, there were smaller increases in children (1-12%) compared with adults (12-25%) at all exercise intensities. There were alterations in [Formula: see text] with exercise intensity in an age-dependent manner [ F (2.5,54.5) = 7.983, P < 0.001; η 2 = 0.266], remaining stable in children with increasing exercise intensity (37-39 mmHg; P > 0.05) until hyperventilation-induced reductions following the respiratory compensation point. In adults, [Formula: see text] increased with exercise intensity (36-45 mmHg, P < 0.05) until the ventilatory threshold. From the ventilatory threshold to maximum, adults showed a greater hyperventilation-induced hypocapnia than children. These findings show that the relative increase in MCAV mean during exercise was attenuated in children compared with adults. There was also a weaker relationship between MCAV mean and [Formula: see text] during exercise in children, suggesting that cerebral perfusion may be regulated by different mechanisms during exercise in the child. NEW & NOTEWORTHY These findings provide the first direct evidence that exercise increases cerebral blood flow in children to a lesser extent than in adults. Changes in end-tidal CO 2 parallel changes in cerebral perfusion in adults but not in children, suggesting age-dependent regulatory mechanisms of cerebral blood flow during exercise. Copyright © 2017 the American Physiological Society.

Acute resistance exercise with blood flow restriction in elderly hypertensive women: haemodynamic, rating of perceived exertion and blood lactate.

PubMed

Pinto, Roberta R; Karabulut, Murat; Poton, Roberto; Polito, Marcos D

2018-01-01

This study aimed to compare haemodynamic, rating of perceived exertion and blood lactate responses during resistance exercise with blood flow restriction (BFR) compared with traditional high-intensity resistance exercise in hypertensive older women. Eighteen hypertensive women (age = 67·0 ± 1·7 years.) undertook three random sessions: (i) three sets; 10 repetitions; 20% of one repetition maximum (1RM) with BFR; (ii) three sets; 10 repetitions; 65% of 1RM; without BFR; and (iii) no-exercise with BFR. The exercise sessions were performed on knee extension equipment. Systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV) and cardiac output (CO) were significantly higher (P<0·05) in all sets of exercise sessions than the control. No statistically significant differences were detected between exercise sessions. However, SBP, DBP and systemic vascular resistance were higher (P<0·05) and SV and CO were lower (P<0·05) during the rest intervals in the session with BFR. The perceived exertion was significantly higher (P<0·01) in the 1st (4·8 ± 0·4 versus 3·1 ± 0·3), 2nd (7·3 ± 0·4 versus 5·7 ± 0·4) and 3rd sets (8·6 ± 0·5 versus 7·5 ± 0·4) of the traditional high-intensity resistance exercise compared with the exercise with BFR. Blood lactate was higher (P<0·05) in the traditional high-intensity resistance exercise (6·2 ± 0·7 mmol) than in the exercise with BFR (4·5 ± 0·4 mmol). In comparison with high-intensity resistance exercise, low-intensity resistance exercise with BFR can elicit: (i) same haemodynamic values during exercise; (ii) lower rating of perceived exertion; (iii) lower blood lactate; (iv) higher haemodynamic demand during the rest intervals. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Influence of exercise on nutritional requirements.

PubMed

Pendergast, D R; Meksawan, K; Limprasertkul, A; Fisher, N M

2011-03-01

There is no consensus on the best diet for exercise, as many variables influence it. We propose an approach that is based on the total energy expenditure of exercise and the specific macro- and micronutrients used. di Prampero quantified the impact of intensity and duration on the energy cost of exercise. This can be used to determine the total energy needs and the balance of fats and carbohydrates (CHO). There are metabolic differences between sedentary and trained persons, thus the total energy intake to prevent overfeeding of sedentary persons and underfeeding athletes is important. During submaximal sustained exercise, fat oxidation (FO) plays an important role. This role is diminished and CHO's role increases as exercise intensity increases. At super-maximal exercise intensities, anaerobic glycolysis dominates. In the case of protein and micronutrients, specific recommendations are required. We propose that for submaximal exercise, the balance of CHO and fat favors fat for longer exercise and CHO for shorter exercise, while always maintaining the minimal requirements of each (CHO: 40% and fat: 30%). A case for higher protein (above 15%) as well as creatine supplementation for resistance exercise has been proposed. One may also consider increasing bicarbonate intake for exercise that relies on anaerobic glycolysis, whereas there appears to be little support for antioxidant supplementation. Insuring minimal levels of substrate will prevent exercise intolerance, while increasing some components may increase exercise tolerance.

Competitive and cooperative arm rehabilitation games played by a patient and unimpaired person: effects on motivation and exercise intensity.

PubMed

Goršič, Maja; Cikajlo, Imre; Novak, Domen

2017-03-23

People with chronic arm impairment should exercise intensely to regain their abilities, but frequently lack motivation, leading to poor rehabilitation outcome. One promising way to increase motivation is through interpersonal rehabilitation games, which allow patients to compete or cooperate together with other people. However, such games have mainly been evaluated with unimpaired subjects, and little is known about how they affect motivation and exercise intensity in people with chronic arm impairment. We designed four different arm rehabilitation games that are played by a person with arm impairment and their unimpaired friend, relative or occupational therapist. One is a competitive game (both people compete against each other), two are cooperative games (both people work together against the computer) and one is a single-player game (played only by the impaired person against the computer). The games were played by 29 participants with chronic arm impairment, of which 19 were accompanied by their friend or relative and 10 were accompanied by their occupational therapist. Each participant played all four games within a single session. Participants' subjective experience was quantified using the Intrinsic Motivation Inventory questionnaire after each game, as well as a final questionnaire about game preferences. Their exercise intensity was quantified using wearable inertial sensors that measured hand velocity in each game. Of the 29 impaired participants, 12 chose the competitive game as their favorite, 12 chose a cooperative game, and 5 preferred to exercise alone. Participants who chose the competitive game as their favorite showed increased motivation and exercise intensity in that game compared to other games. Participants who chose a cooperative game as their favorite also showed increased motivation in cooperative games, but not increased exercise intensity. Since both motivation and intensity are positively correlated with rehabilitation outcome, competitive games have high potential to lead to functional improvement and increased quality of life for patients compared to conventional rehabilitation exercises. Cooperative games do not increase exercise intensity, but could still increase motivation of patients who do not enjoy competition. However, such games need to be tested in longer, multisession studies to determine whether the observed increases in motivation and exercise intensity persist over a longer period of time and whether they positively affect rehabilitation outcome. The study is not a clinical trial. While human subjects are involved, they participate in a single-session evaluation of a rehabilitation game rather than a full rehabilitation intervention, and no health outcomes are examined.

Possible influences of exercise-intensity-dependent increases in non-cortical hemodynamic variables on NIRS-based neuroimaging analysis during cognitive tasks: Technical note

PubMed Central

Byun, Kyeongho; Hyodo, Kazuki; Suwabe, Kazuya; Kujach, Sylwester; Kato, Morimasa; Soya, Hideaki

2014-01-01

[Purpose] Functional near-infrared spectroscopy (fNIRS) provides functional imaging of cortical activations by measuring regional oxy- and deoxy-hemoglobin (Hb) changes in the forehead during a cognitive task. There are, however, potential problems regarding NIRS signal contamination by non-cortical hemodynamic (NCH) variables such as skin blood flow, middle cerebral artery blood flow, and heart rate (HR), which are further complicated during acute exercise. It is thus necessary to determine the appropriate post-exercise timing that allows for valid NIRS assessment during a task without any increase in NCH variables. Here, we monitored post-exercise changes in NCH parameters with different intensities of exercise. [Methods] Fourteen healthy young participants cycled 30, 50 and 70% of their peak oxygen uptake (Vo2peak) for 10 min per intensity, each on different days. Changes in skin blood flow velocity (SBFv), middle cerebral artery mean blood velocity (MCA Vmean) and HR were monitored before, during, and after the exercise. [Results] Post-exercise levels of both SBFv and HR in contrast to MCA Vmean remained high compared to basal levels and the times taken to return to baseline levels for both parameters were delayed (2-8 min after exercise), depending upon exercise intensity. [Conclusion] These results indicate that the delayed clearance of NCH variables of up to 8 min into the post-exercise phase may contaminate NIRS measurements, and could be a limitation of NIRS-based neuroimaging studies. PMID:25671198

Nandrolone Plus Moderate Exercise Increases the Susceptibility to Lethal Arrhythmias

PubMed Central

Ghorbani Baravati, Hamideh; Joukar, Siyavash; Fathpour, Hossein; Kordestani, Zeinab

2015-01-01

Background: Until now, no experimental study has directly assessed the arrhythmogenesis of chronic consumption of anabolic androgenic steroids along with moderate-intensity endurance exercise. Objectives: We evaluated the influence of integration of anabolic androgenic steroids along with moderate-intensity endurance exercise on susceptibility to lethal ventricular arrhythmias in rat. Materials and Methods: The animal groups were as follows: control group (CTL); exercise group (EX) which were under 6 weeks of treadmill exercise; nandrolone group (Nan) which received 5 mg/kg of nandrolone decanoate twice a week; vehicle group (Arach) which received Arachis oil (solvent of nandrolone); trained vehicle group (Arach + Ex); and trained nandrolone group (Nan + Ex). One day after ending of the intervention period, arrhythmia was inducted by intravenous infusion of aconitine and ventricular arrhythmias were recorded. Then malondialdehyde (MDA) and glutathione peroxidase (GPX) of heart tissue were measured. Results: Nandrolone, exercise, and their combination were associated with heart hypertrophy. Exercise could prevent the incremental effect of nandrolone on MDA/GPX ratio. Chronic administration of nandrolone with moderate-intensity endurance exercise had no significant effect on blood pressure, heart rate, and basal electrocardiographic parameters. Combination of nandrolone and exercise significantly increased the incidence of ventricular fibrillation (VF) and reduced the VF latency (P < 0.05). Conclusions: The findings suggest that chronic coadministration of nandrolone with moderate-intensity endurance exercise facilitates the VF occurrence in rat. Complementary studies are needed to elucidate the involved mechanisms of this abnormality. PMID:26396972

Patterning of physiological and affective responses in older active adults during a maximal graded exercise test and self-selected exercise.

PubMed

Smith, Ashleigh E; Eston, Roger; Tempest, Gavin D; Norton, Belinda; Parfitt, Gaynor

2015-09-01

The American College of Sports Medicine has highlighted the importance of considering the physiological and affective responses to exercise when setting exercise intensity. Here, we examined the relationship between exercise intensity and physiological and affective responses in active older adults. Eighteen participants (60-74 years; 64.4 ± 3.9; 8 women) completed a maximal graded exercise test (GXT) on a treadmill. Since time to exhaustion in the GXT differed between participants, heart rate (HR), oxygen consumption (VO2), affective valence (affect) and rating of perceived exertion (RPE) were expressed relative to the individually determined ventilatory threshold (%atVT). During the GXT, VO2, HR and RPE increased linearly (all P < 0.01). Affect declined initially (but remained positive) (P = 0.03), stabilised around VT (still positive) (P > 0.05) and became negative towards the end of the test (P < 0.01). In a subsequent session, participants completed a 20-min bout of self-selected exercise (at a preferred intensity). Initially, participants chose to exercise below VT (88.2 ± 17.4 %VO2atVT); however, the intensity was adjusted to work at, or above VT (107.7 ± 19.9 %VO2atVT) after 10 min (P < 0.001), whilst affect remained positive. Together, these findings indicate that exercise around VT, whether administered during an exercise test, or self-selected by the participant, is likely to result in positive affective responses in older adults.

New perspectives concerning feedback influences on cardiorespiratory control during rhythmic exercise and on exercise performance.

PubMed

Dempsey, Jerome A

2012-09-01

The cardioaccelerator and ventilatory responses to rhythmic exercise in the human are commonly viewed as being mediated predominantly via feedforward 'central command' mechanisms, with contributions from locomotor muscle afferents to the sympathetically mediated pressor response. We have assessed the relative contributions of three types of feedback afferents on the cardiorespiratory response to voluntary, rhythmic exercise by inhibiting their normal 'tonic' activity in healthy animals and humans and in chronic heart failure. Transient inhibition of the carotid chemoreceptors during moderate intensity exercise reduced muscle sympathetic nerve activity (MSNA) and increased limb vascular conductance and blood flow; and reducing the normal level of respiratory muscle work during heavier intensity exercise increased limb vascular conductance and blood flow. These cardiorespiratory effects were prevented via ganglionic blockade and were enhanced in chronic heart failure and in hypoxia. Blockade of μ opioid sensitive locomotor muscle afferents, with preservation of central motor output via intrathecal fentanyl: (a) reduced the mean arterial blood pressure (MAP), heart rate and ventilatory responses to all steady state exercise intensities; and (b) during sustained high intensity exercise, reduced O(2) transport, increased central motor output and end-exercise muscle fatigue and reduced endurance performance. We propose that these three afferent reflexes - probably acting in concert with feedforward central command - contribute significantly to preserving O(2) transport to locomotor and to respiratory muscles during exercise. Locomotor muscle afferents also appear to provide feedback concerning the metabolic state of the muscle to influence central motor output, thereby limiting peripheral fatigue development.

Substrate Metabolism During Ironman Triathlon: Different Horses on the Same Courses.

PubMed

Maunder, Ed; Kilding, Andrew E; Plews, Daniel J

2018-05-18

Ironman triathlons are ultra-endurance events of extreme duration. The performance level of those competing varies dramatically, with elite competitors finishing in ~ 8:00:00, and lower performing amateurs finishing in ~ 14-15:00:00. When applying appropriate values for swimming, cycling and running economies to these performance times, it is demonstrated that the absolute energy cost of these events is high, and the rate of energy expenditure increases in proportion with the athlete's competitive level. Given the finite human capacity for endogenous carbohydrate storage, minimising the endogenous carbohydrate cost associated with performing exercise at competitive intensities should be a goal of Ironman preparation. A range of strategies exist that may help to achieve this goal, including, but not limited to, adoption of a low-carbohydrate diet, exogenous carbohydrate supplementation and periodised training with low carbohydrate availability. Given the diverse metabolic stimuli evoked by Ironman triathlons at different performance levels, it is proposed that the performance level of the Ironman triathlete is considered when adopting metabolic strategies to minimise the endogenous carbohydrate cost associated with exercise at competitive intensities. Specifically, periodised training with low carbohydrate availability combined with exogenous carbohydrate supplementation during competition might be most appropriate for elite and top-amateur Ironman triathletes who elicit very high rates of energy expenditure. Conversely, the adoption of a low-carbohydrate or ketogenic diet might be appropriate for some lower performance amateurs (> 12 h), in whom associated high rates of fat oxidation may be almost completely sufficient to match the energy demands required.

The relationship between aerobic fitness and recovery from high-intensity exercise in infantry soldiers.

PubMed

Hoffman, J R

1997-07-01

The relationship between aerobic fitness and recovery from high-intensity exercise was examined in 197 infantry soldiers. Aerobic fitness was determined by a maximal-effort, 2,000-m run (RUN). High-intensity exercise consisted of three bouts of a continuous 140-m sprint with several changes of direction. A 2-minute passive rest separated each sprint. A fatigue index was developed by dividing the mean time of the three sprints by the fastest time. Times for the RUN were converted into standardized T scores and separated into five groups (group 1 had the slowest run time and group 5 had the fastest run time). Significant differences in the fatigue index were seen between group 1 (4.9 +/- 2.4%) and groups 3 (2.6 +/- 1.7%), 4 (2.3 +/- 1.6%), and 5 (2.3 +/- 1.3%). It appears that recovery from high-intensity exercise is improved at higher levels of aerobic fitness (faster time for the RUN). However, as the level of aerobic fitness improves above the population mean, no further benefit in the recovery rate from high-intensity exercise is apparent.

Efficacy and consequences of very-high-protein diets for athletes and exercisers.

PubMed

Tipton, Kevin D

2011-05-01

Athletes and exercisers have utilised high-protein diets for centuries. The objective of this review is to examine the evidence for the efficacy and potential dangers of high-protein diets. One important factor to consider is the definition of a 'high-protein diet'. There are several ways to consider protein content of a diet. The composition of the diet can be determined as the absolute amount of the protein (or other nutrient of interest), the % of total energy (calories) as protein and the amount of protein ingested per kg of body weight. Many athletes consume very high amounts of protein. High-protein diets most often are associated with muscle hypertrophy and strength, but now also are advocated for weight loss and recovery from intense exercise or injuries. Prolonged intake of a large amount of protein has been associated with potential dangers, such as bone mineral loss and kidney damage. In otherwise healthy individuals, there is little evidence that high protein intake is dangerous. However, kidney damage may be an issue for individuals with already existing kidney dysfunction. Increased protein intake necessarily means that overall energy intake must increase or consumption of either carbohydrate or fat must decrease. In conclusion, high protein intake may be appropriate for some athletes, but there are potential negative consequences that must be carefully considered before adopting such a diet. In particular, care must be taken to ensure that there is sufficient intake of other nutrients to support the training load.

OCT angiography by absolute intensity difference applied to normal and diseased human retinas

PubMed Central

Ruminski, Daniel; Sikorski, Bartosz L.; Bukowska, Danuta; Szkulmowski, Maciej; Krawiec, Krzysztof; Malukiewicz, Grazyna; Bieganowski, Lech; Wojtkowski, Maciej

2015-01-01

We compare four optical coherence tomography techniques for noninvasive visualization of microcapillary network in the human retina and murine cortex. We perform phantom studies to investigate contrast-to-noise ratio for angiographic images obtained with each of the algorithm. We show that the computationally simplest absolute intensity difference angiographic OCT algorithm that bases only on two cross-sectional intensity images may be successfully used in clinical study of healthy eyes and eyes with diabetic maculopathy and branch retinal vein occlusion. PMID:26309740

Benefits of Moderate-Intensity Exercise during a Calorie-Restricted Low-Fat Diet

ERIC Educational Resources Information Center

Apekey, Tanefa A.; Morris, A. E. J.; Fagbemi, S.; Griffiths, G. J.

2012-01-01

Objective: Despite the health benefits, many people do not undertake regular exercise. This study investigated the effects of moderate-intensity exercise on cardiorespiratory fitness (lung age, blood pressure and maximal aerobic power, VO[subscript 2]max), serum lipids concentration and body mass index (BMI) in sedentary overweight/obese adults…

Effect of maximal-intensity exercise on systemic nitro-oxidative stress in men and women.

PubMed

Wiecek, Magdalena; Maciejczyk, Marcin; Szymura, Jadwiga; Szygula, Zbigniew

2017-07-01

The aim of this study was to test the hypotheses: (1) there is a negative correlation between protein and lipid oxidative damage following maximal-intensity exercise, and oxygen uptake and work intensity (%VO 2max ) at the respiratory compensation point (RCP) in women and men; (2) nitro-oxidative stress following maximal-intensity exercise results from the intensification of anaerobic processes and muscle fibre micro-damage. Study participants comprised 20 women (21.34±1.57 years) and 20 men (21.97±1.41 years) who performed a treadmill incremental test (IT); VO 2max : 45.08 ± 0.91 and 57.38 ± 1.22 mL kg -1  min -1 for women and men, respectively. The oxidized low-density lipoprotein (ox-LDL), 3-nitrotyrosine (3-NT) concentration and creatine kinase (CK) as well as lactate dehydrogenase (LDH) activity were measured in the blood serum, and total antioxidative capacity (TAC) and lactate concentration (Lac) were determined in blood plasma before and after IT. After the IT, increases in ox-LDL, 3-NT, CK, and LDH were seen in both groups (P < 0.05). After the IT, an increase in the TAC was only observed in women (P < 0.05). The post-exercise-induced increase in Lac was significantly higher in men than in women. Only in the group of women was a positive correlation (P < 0.05) between the post-exercise increase in TAC and changes in CK activity and LDH found. The gain of ox-LDL and 3-NT following maximal-intensity exercise is independent of VO 2max , oxygen consumption and exercise intensity at RCP. This increase of ox-LDL and 3-NT is indicative of similar lipid and protein damage in women and men. A significant increase in TAC in women following maximal-intensity exercise is the result of muscle fibre micro-injuries.

Electric motor assisted bicycle as an aerobic exercise machine.

PubMed

Nagata, T; Okada, S; Makikawa, M

2012-01-01

The goal of this study is to maintain a continuous level of exercise intensity around the aerobic threshold (AT) during riding on an electric motor assisted bicycle using a new control system of electrical motor assistance which uses the efficient pedaling rate of popular bicycles. Five male subjects participated in the experiment, and the oxygen uptake was measured during cycling exercise using this new pedaling rate control system of electrical motor assistance, which could maintain the pedaling rate within a specific range, similar to that in previous type of electrically assisted bicycles. Results showed that this new pedaling rate control system at 65 rpm ensured continuous aerobic exercise intensity around the AT in two subjects, and this intensity level was higher than that observed in previous type. However, certain subjects were unable to maintain the expected exercise intensity because of their particular cycling preferences such as the pedaling rate. It is necessary to adjust the specific pedaling rate range of the electrical motor assist control according to the preferred pedaling rate, so that this system becomes applicable to anyone who want continuous aerobic exercise.

[Performance enhancement by carbohydrate intake during sport: effects of carbohydrates during and after high-intensity exercise].

PubMed

Beelen, Milou; Cermak, Naomi M; van Loon, Luc J C

2015-01-01

Endogenous carbohydrate availability does not provide sufficient energy for prolonged moderate to high-intensity exercise. Carbohydrate ingestion during high-intensity exercise can therefore enhance performance.- For exercise lasting 1 to 2.5 hours, athletes are advised to ingest 30-60 g of carbohydrates per hour.- Well-trained endurance athletes competing for longer than 2.5 hours at high intensity can metabolise up to 90 g of carbohydrates per hour, provided that a mixture of glucose and fructose is ingested.- Athletes participating in intermittent or team sports are advised to follow the same strategies but the timing of carbohydrate intake depends on the type of sport.- If top performance is required again within 24 hours after strenuous exercise, the advice is to supplement endogenous carbohydrate supplies quickly within the first few hours post-exercise by ingesting large amounts of carbohydrate (1.2 g/kg/h) or a lower amount of carbohydrate (0.8 g/kg/h) with a small amount of protein (0.2-0.4 g/kg/h).

Physical exercise-induced changes in the core body temperature of mice depend more on ambient temperature than on exercise protocol or intensity

NASA Astrophysics Data System (ADS)

Wanner, Samuel Penna; Costa, Kátia Anunciação; Soares, Anne Danieli Nascimento; Cardoso, Valbert Nascimento; Coimbra, Cândido Celso

2014-08-01

The mechanisms underlying physical exercise-induced hyperthermia may be species specific. Therefore, the present study aimed to investigate the effects of exercise intensity and ambient temperature on the core body temperature ( T core) of running mice, which provide an important experimental model for advancing the understanding of thermal physiology. We evaluated the influence of different protocols (constant- or incremental-speed exercises), treadmill speeds and ambient temperatures ( T a) on the magnitude of exercise-induced hyperthermia. To measure T core, a telemetric sensor was implanted in the abdominal cavity of male adult Swiss mice under anesthesia. After recovering from the surgery, the animals were familiarized to running on a treadmill and then subjected to the different running protocols and speeds at two T a: 24 °C or 34 °C. All of the experimental trials resulted in marked increases in T core. As expected, the higher-temperature environment increased the magnitude of running-induced hyperthermia. For example, during incremental exercise at 34 °C, the maximal T core achieved was increased by 1.2 °C relative to the value reached at 24 °C. However, at the same T a, neither treadmill speed nor exercise protocol altered the magnitude of exercise-induced hyperthermia. We conclude that T core of running mice is influenced greatly by T a, but not by the exercise protocols or intensities examined in the present report. These findings suggest that the magnitude of hyperthermia in running mice may be regulated centrally, independently of exercise intensity.

Physical exercise-induced changes in the core body temperature of mice depend more on ambient temperature than on exercise protocol or intensity.

PubMed

Wanner, Samuel Penna; Costa, Kátia Anunciação; Soares, Anne Danieli Nascimento; Cardoso, Valbert Nascimento; Coimbra, Cândido Celso

2014-08-01

The mechanisms underlying physical exercise-induced hyperthermia may be species specific. Therefore, the present study aimed to investigate the effects of exercise intensity and ambient temperature on the core body temperature (T core) of running mice, which provide an important experimental model for advancing the understanding of thermal physiology. We evaluated the influence of different protocols (constant- or incremental-speed exercises), treadmill speeds and ambient temperatures (T a) on the magnitude of exercise-induced hyperthermia. To measure T core, a telemetric sensor was implanted in the abdominal cavity of male adult Swiss mice under anesthesia. After recovering from the surgery, the animals were familiarized to running on a treadmill and then subjected to the different running protocols and speeds at two T a: 24 °C or 34 °C. All of the experimental trials resulted in marked increases in T core. As expected, the higher-temperature environment increased the magnitude of running-induced hyperthermia. For example, during incremental exercise at 34 °C, the maximal T core achieved was increased by 1.2 °C relative to the value reached at 24 °C. However, at the same T a, neither treadmill speed nor exercise protocol altered the magnitude of exercise-induced hyperthermia. We conclude that T core of running mice is influenced greatly by T a, but not by the exercise protocols or intensities examined in the present report. These findings suggest that the magnitude of hyperthermia in running mice may be regulated centrally, independently of exercise intensity.

Comparative effects of proprioceptive and isometric exercises on pain intensity and difficulty in patients with knee osteoarthritis: A randomised control study.

PubMed

Ojoawo, Adesola O; Olaogun, Matthew O B; Hassan, Mariam A

2016-11-14

The study compared the effects of isometric quadriceps exercise and proprioceptive exercise on pain, joint stiffness and physical difficulties of patients with knee osteoarthritis. Forty-five patients with history of knee osteoarthritis were randomly allocated into two groups; A with 23 subjects and B with 22 subjects. All subjects received infrared radiation for 20 minutes and kneading massage with methyl salicylate ointment. Group A underwent proprioceptive exercises while Group B had isometric quadriceps exercise. Each exercise session lasted for 10 minutes according to standard protocol, twice in a week for six weeks. Pre-treatment, 3rd week and 6th week pain intensity, joint stiffness and physical difficulties were assessed using Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) questionnaire. Statistical package for social sciences (SPSS) version 17 was used to analyse the data while descriptive and inferential statistics were used to summarise the result. Proprioceptive exercises reduced pain intensity significantly (F = 4.76; p = 0.00) at 6th week with effect size of 2.79, and physical difficulty (F = 3.69; p < 0.04) with effect size of 7.53 better than isometric exercises. There was a significant reduction in the pain intensity (F = 12.08; p < 0.001), and physical difficulties (F = 3.69, p = 0.04) in pre-treatment, 3rd week and 6th week in both Group A and B. Both exercises are effective but proprioceptive exercises may be more effective in the management of patients with knee osteoarthritis (KOA) than isometric exercises.

Anxiety Sensitivity as a Mediator of the Relationship between Moderate-Intensity Exercise and Coping-Oriented Marijuana Use Motives

PubMed Central

Smits, Jasper A. J.; Bonn-Miller, Marcel O.; Tart, Candyce D.; Irons, Jessica G.; Zvolensky, Michael J.

2011-01-01

The present study examined the working hypothesis that moderate-intensity exercise is associated with coping-oriented marijuana use motives through its association with the fear of somatic arousal (i.e., anxiety sensitivity). Using data from 146 young adult current marijuana users we found evidence consistent with this hypothesis. Specifically, moderate-intensity exercise was associated with coping-oriented use motives, even after controlling for frequency of current marijuana use and other co-occurring marijuana use motives. This relationship became non-significant after entering anxiety sensitivity as an additional predictor variable, denoting a putative mediational role for this cognitve factor. These findings extend previous work and offer support for the potential utility of moderate-intensity aerobic exercise for the treatment of marijuana use problems. PMID:21314753

Effects of aerobic exercise intensity on ambulatory blood pressure and vascular responses in resistant hypertension: a crossover trial.

PubMed

Santos, Lucas P; Moraes, Ruy S; Vieira, Paulo J C; Ash, Garrett I; Waclawovsky, Gustavo; Pescatello, Linda S; Umpierre, Daniel

2016-07-01

Resistant hypertension often exposes patients to poor blood pressure (BP) control, resulting in clinical vulnerability, possible need for device-based procedures (denervation) and increased therapy costs. Regular exercise markedly benefits patients with hypertension, including resistant patients. However, little is known about short-term exercise effects in resistant hypertension. To evaluate acute hemodynamic effects of exercise in resistant hypertension. After maximal exercise testing, 20 patients (54.0 ± 5.7 years, 30.2 ± 4.9 kg/m) with resistant hypertension participated in three crossover interventions, in random order, and on separate days: control (45' of rest), and light intensity and moderate intensity (45' of aerobic exercise at 50 and 75% of maximum heart rate, respectively). Ambulatory BP, forearm blood flow (with subsequent calculation of vascular resistance), and reactive hyperemia were measured before and after interventions trough venous occlusion plethysmography. Compared with control, both exercise intensities reduced ambulatory systolic pressure over 5 h (light: -7.7 ± 2.4 mmHg and moderate: -9.4 ± 2.8 mmHg, P < 0.01), whereas only light intensity reduced diastolic pressure (-5.7 ± 2.2 mmHg, P < 0.01). Light intensity also lowered systolic and diastolic pressures over 10-h daytime (-3.8 ± 1.3 and -4.0 ± 1.3 mmHg, respectively, P < 0.02), night-time (-6.0 ± 2.4 and -6.1 ± 1.6 mmHg, respectively, P < 0.05), and diastolic pressure over 19 h (-4.8 ± 1.2 mmHg, P < 0.01). Forearm blood flow changed (decreased) compared with baseline only at 50 min after light intensity (P < 0.05). After the control and light intensity sessions, vascular resistance increased at the end of 1 h, and after moderate intensity, it decreased only at the moment (∼2 min) immediately after intervention (P < 0.05). A single session of light or moderate aerobic exercise acutely reduces ambulatory BP in resistant hypertension, although benefits persist longer following light intensity.

A Single Bout of High-Intensity Interval Training Improves Motor Skill Retention in Individuals With Stroke.

PubMed

Nepveu, Jean-Francois; Thiel, Alexander; Tang, Ada; Fung, Joyce; Lundbye-Jensen, Jesper; Boyd, Lara A; Roig, Marc

2017-08-01

One bout of high-intensity cardiovascular exercise performed immediately after practicing a motor skill promotes changes in the neuroplasticity of the motor cortex and facilitates motor learning in nondisabled individuals. To determine if a bout of exercise performed at high intensity is sufficient to induce neuroplastic changes and improve motor skill retention in patients with chronic stroke. Twenty-two patients with different levels of motor impairment were recruited. On the first session, the effects of a maximal graded exercise test on corticospinal and intracortical excitability were assessed from the affected and unaffected primary motor cortex representational area of a hand muscle with transcranial magnetic stimulation. On the second session, participants were randomly assigned to an exercise or a nonexercise control group. Immediately after practicing a motor task, the exercise group performed 15 minutes of high-intensity interval training while the control group rested. Twenty-four hours after motor practice all participants completed a test of the motor task to assess skill retention. The graded exercise test reduced interhemispheric imbalances in GABA A -mediated short-interval intracortical inhibition but changes in other markers of excitability were not statistically significant. The group that performed high-intensity interval training showed a better retention of the motor skill. The performance of a maximal graded exercise test triggers only modest neuroplastic changes in patients with chronic stroke. However, a single bout of high-intensity interval training performed immediately after motor practice improves skill retention, which could potentially accelerate motor recovery in these individuals.

Is lactate production related to muscular fatigue? A pedagogical proposition using empirical facts.

PubMed

Macedo, Denise Vaz; Lazarim, Fernanda Lorenzi; Catanho da Silva, Fernando Oliveira; Tessuti, Lucas Samuel; Hohl, Rodrigo

2009-12-01

The cause-effect relationship between lactic acid, acidosis, and muscle fatigue has been established in the literature. However, current experiments contradict this premise. Here, we describe an experiment developed by first-year university students planned to answer the following questions: 1) Which metabolic pathways of energy metabolism are responsible for meeting the high ATP demand during high-intensity intermittent exercise? 2) Which metabolic pathways are active during the pause, and how do they influence phosphocreatine synthesis? and 3) Is lactate production related to muscular fatigue? Along with these questions, students received a list of materials available for the experiment. In the classroom, they proposed two protocols of eight 30-m sprints at maximum speed, one protocol with pauses of 120 s and the other protocol with pauses of 20 s between sprints. Their performances were analyzed through the velocity registered by photocells. Blood lactate was analyzed before the first sprint and after the eighth sprint. Blood uric acid was analyzed before exercise and 15 and 60 min after exercises. When discussing the data, students concluded that phosphocreatine restoration is time dependent, and this fact influenced the steady level of performance in the protocol with pauses of 120 s compared with the performance decrease noted in the protocol with pauses of 20 s. As the blood lactate levels showed similar absolute increases after both exercises, the students concluded that lactate production is not related to the performance decrement. This activity allows students to integrate the understanding of muscular energy pathways and to reconsider a controversial concept with facts that challenge the universality of the hypothesis relating lactate production to muscular fatigue.

A preliminary, randomized trial of aerobic exercise for alcohol dependence

PubMed Central

Brown, Richard A.; Abrantes, Ana M.; Minami, Haruka; Read, Jennifer P.; Marcus, Bess H.; Jakicic, John M.; Strong, David R.; Dubreuil, Mary Ella; Gordon, Alan A.; Ramsey, Susan E.; Kahler, Christopher W.; Stuart, Gregory L.

2015-01-01

Interventions targeting physical activity may be valuable as an adjunct to alcohol treatment, but have been relative untested. In the current study, alcohol dependent, physically sedentary patients were randomized to: a 12-week moderate-intensity, group aerobic exercise intervention (AE; n = 25) or a brief advice to exercise intervention (BA-E; n=23). Results showed that individuals in AE reported significantly fewer drinking and heavy drinking days, relative to BA-E during treatment. Furthermore adherence to AE strengthened the beneficial effect of intervention on alcohol use outcomes. While high levels of moderate-intensity exercise appeared to facilitate alcohol recovery regardless of intervention arm, attending the group-based AE intervention seemed to further enhance the positive effects of exercise on alcohol use. Study findings indicate that a moderate intensity, group aerobic exercise intervention is an efficacious adjunct to alcohol treatment. Improving adherence to the intervention may enhance its beneficial effects on alcohol use. PMID:24666811

Atypical blood glucose response to continuous and interval exercise in a person with type 1 diabetes: a case report.

PubMed

Moser, Othmar; Tschakert, Gerhard; Mueller, Alexander; Groeschl, Werner; Pieber, Thomas R; Koehler, Gerd; Eckstein, Max L; Bracken, Richard M; Hofmann, Peter

2017-06-30

Therapy must be adapted for people with type 1 diabetes to avoid exercise-induced hypoglycemia caused by increased exercise-related glucose uptake into muscles. Therefore, to avoid hypoglycemia, the preexercise short-acting insulin dose must be reduced for safety reasons. We report a case of a man with long-lasting type 1 diabetes in whom no blood glucose decrease during different types of exercise with varying exercise intensities and modes was found, despite physiological hormone responses. A Caucasian man diagnosed with type 1 diabetes for 24 years performed three different continuous high-intensity interval cycle ergometer exercises as part of a clinical trial (ClinicalTrials.gov identifier NCT02075567). Intensities for both modes of exercises were set at 5% below and 5% above the first lactate turn point and 5% below the second lactate turn point. Short-acting insulin doses were reduced by 25%, 50%, and 75%, respectively. Measurements taken included blood glucose, blood lactate, gas exchange, heart rate, adrenaline, noradrenaline, cortisol, glucagon, and insulin-like growth factor-1. Unexpectedly, no significant blood glucose decreases were observed during all exercise sessions (start versus end, 12.97 ± 2.12 versus 12.61 ± 2.66 mmol L -1 , p = 0.259). All hormones showed the expected response, dependent on the different intensities and modes of exercises. People with type 1 diabetes typically experience a decrease in blood glucose levels, particularly during low- and moderate-intensity exercises. In our patient, we clearly found no decline in blood glucose, despite a normal hormone response and no history of any insulin insensitivity. This report indicates that there might be patients for whom the recommended preexercise therapy adaptation to avoid exercise-induced hypoglycemia needs to be questioned because this could increase the risk of severe hyperglycemia and ketosis.

The Acute Effect of Exercise Intensity on Vascular Function in Adolescents.

PubMed

Bond, Bert; Hind, Siobhan; Williams, Craig A; Barker, Alan R

2015-12-01

Impairments in vascular function are present in asymptomatic youths with risk factors for cardiovascular disease. Exercise can promote vascular health in youth, but the effects of exercise intensity and the time course in response to acute exercise are unknown. Twenty adolescents (10 male, 14.1 ± 0.3 yr) performed the following on separate days in a counterbalanced order: 1) cycling at 90% of the gas exchange threshold (moderate-intensity exercise (MIE)) and 2) 8 × 1-min cycling at 90% peak power with 75-s recovery (high-intensity interval exercise (HIIE)). The duration of MIE (25.8 ± 2.1 min) was work-matched to HIIE (23.0 min). Macro- and microvascular functions were assessed before, immediately after, and 1 and 2 h after exercise by flow-mediated dilation (FMD) and laser Doppler imaging (total reactive hyperemia). FMD was attenuated immediately after HIIE (P < 0.001, effect size (ES) = 1.20) but not after MIE (P = 0.28, ES = 0.26). Compared with that before exercise, FMD was elevated 1 and 2 h after HIIE (P < 0.001, ES = 1.33; P < 0.001, ES = 1.36) but unchanged in MIE (P = 0.67, ES = 0.10; P = 0.72, ES = 0.08). Changes in FMD were unrelated to shear or baseline arterial diameter. Compared with that in preexercise, total reactive hyperemia was always greater after MIE (P < 0.02, ES > 0.60 for all) and HIIE (P < 0.001, ES > 1.18 for all). Total reactive hyperemia was greater in HIIE compared with that in MIE immediately after (P = 0.03, ES = 0.67) and 1 h after (P = 0.01, ES = 0.62) exercise, with a trend to be greater 2 h after (P = 0.06, ES = 0.45). Exercise intensity is positively associated with macro- and microvascular function 1 and 2 h after exercise. Performing HIIE may provide superior vascular benefits than MIE in adolescents.

Comparison between Nintendo Wii Fit aerobics and traditional aerobic exercise in sedentary young adults.

PubMed

Douris, Peter C; McDonald, Brittany; Vespi, Frank; Kelley, Nancy C; Herman, Lawrence

2012-04-01

Exergaming is becoming a popular recreational activity for young adults. The purpose was to compare the physiologic and psychological responses of college students playing Nintendo Wii Fit, an active video game console, vs. an equal duration of moderate-intensity brisk walking. Twenty-one healthy sedentary college-age students (mean age 23.2 ± 1.8 years) participated in a randomized, double cross-over study, which compared physiologic and psychological responses to 30 minutes of brisk walking exercise on a treadmill vs. 30 minutes playing Nintendo Wii Fit "Free Run" program. Physiologic parameters measured included heart rate, rate pressure product, respiratory rate, and rating of perceived exertion. Participants' positive well-being, psychological distress, and level of fatigue associated with each exercise modality were quantified using the Subjective Exercise Experience Scale. The mean maximum heart rate (HRmax) achieved when exercising with Wii Fit (142.4 ± 20.5 b·min(-1)) was significantly greater (p = 0.001) compared with exercising on the treadmill (123.2 ± 13.7 b·min(-1)). Rate pressure product was also significantly greater (p = 0.001) during exercise on the Wii Fit. Participants' rating of perceived exertion when playing Wii Fit (12.7 ± 3.0) was significantly greater (p = 0.014) when compared with brisk walking on the treadmill (10.1 ± 3.3). However, psychologically when playing Wii Fit, participants' positive well-being decreased significantly (p = 0.018) from preexercise to postexercise when compared with exercising on the treadmill. College students have the potential to surpass exercise intensities achieved when performing a conventional standard for moderate-intensity exercise when playing Nintendo Wii Fit "Free Run" with a self-selected intensity. We concluded that Nintendo Wii Fit "Free Run" may act as an alternative to traditional moderate-intensity aerobic exercise in fulfilling the American College of Sports Medicine requirements for physical activity.

Haemolysis caused by alterations of alpha- and beta-spectrin after 10 to 35 min of severe exercise.

PubMed

Beneke, Ralph; Bihn, Detlef; Hütler, Matthias; Leithäuser, Renate M

2005-10-01

The pathophysiology of exercise related haemolysis is not thoroughly understood. We investigated whether exercise related haemolysis (1) is associated with alterations of red blood cell (RBC) membrane proteins similar to those found in inherited anaemic diseases, (2) can be induced with a non-running exercise mode, (3) is related to exercise intensity, and (4) coincides with indicators of oxidative stress. In ten triathletes [median (P25/P75-percentiles) age: 28.0 (26.3/28.5) years, height: 1.84 (1.78/1.87) m, body mass: 78.5 (74.8/80.8) kg, maximal oxygen uptake: 60.0 (57.3/64.8) ml kg(-1) min(-1)], haptoglobin, alpha- and beta-spectrin bands, malondialdehyde (MDA) and H2O2-induced chemiluminescence (H2O2-Chem) were determined immediately pre- and post-both, a 35 min low intensity and a high intensity cycling exercise [240 (218/253) vs 290 (270/300) W, P<0.05) requiring similar amounts of metabolic energy [28.3 (25.9/29.9) vs 24.9 (18.4/30.5) kJ kg(-1), P>0.05]. At high exercise intensity haptoglobin [1.10 (0.81/2.53) vs 1.01 (0.75/2.00) g l(-1)] decreased (P<0.05) whilst MDA [2.80 (2.65/3.20) vs 3.13 (2.78/3.31) nmol ml(-1)] and H2O2-Chem [29.70 (22.55/37.10) vs 37.25 (35.20/52.63) rel. U min] increased (P<0.05), coinciding with the disappearance of the spectrin bands in six out of ten gels. No corresponding changes were found at low intensity exercise. Ten to 35 min of non-running exercise in a regularly used intensity domain causes intra-vascular haemolysis associated with alterations in the RBC membrane proteins similar to those found after in vitro oxidative stress and in inherited anaemic diseases like Sphaerocytosis and Fanconi's anaemia.

The effect of endothelin A and B receptor blockade on cutaneous vascular and sweating responses in young men during and following exercise in the heat.

PubMed

Fujii, Naoto; Singh, Maya S; Halili, Lyra; Louie, Jeffrey C; Kenny, Glen P

2016-12-01

During exercise, cutaneous vasodilation and sweating responses occur, whereas these responses rapidly decrease during postexercise recovery. We hypothesized that the activation of endothelin A (ET A ) receptors, but not endothelin B (ET B ) receptors, attenuate cutaneous vasodilation during high-intensity exercise and contribute to the subsequent postexercise suppression of cutaneous vasodilation. We also hypothesized that both receptors increase sweating during and following high-intensity exercise. Eleven men (24 ± 4 yr) performed an intermittent cycling protocol consisting of two 30-min bouts of moderate- (40% V̇o 2peak ) and high-intensity (75% V̇o 2peak ) exercise in the heat (35°C), each separated by a 20- and 40-min recovery period, respectively. Cutaneous vascular conductance (CVC) and sweat rate were evaluated at four intradermal microdialysis skin sites: 1) lactated Ringer (control), 2) 500 nM BQ123 (a selective ET A receptor blocker), 3) 300 nM BQ788 (a selective ET B receptor blocker), or 4) a combination of BQ123 + BQ788. There were no between-site differences in CVC during each exercise bout (all P > 0.05); however, CVC following high-intensity exercise was greater at BQ123 (56 ± 9%max) and BQ123 + BQ788 (55 ± 14%max) sites relative to the control site (43 ± 12%max) (all P ≤ 0.05). Sweat rate did not differ between sites throughout the protocol (all P > 0.05). We show that neither ET A nor ET B receptors modulate cutaneous vasodilation and sweating responses during and following moderate- and high-intensity exercise in the heat, with the exception that ET A receptors may partly contribute to the suppression of cutaneous vasodilation following high-intensity exercise. Copyright © 2016 the American Physiological Society.

Where does HIT fit? An examination of the affective response to high-intensity intervals in comparison to continuous moderate- and continuous vigorous-intensity exercise in the exercise intensity-affect continuum.

PubMed

Jung, Mary E; Bourne, Jessica E; Little, Jonathan P

2014-01-01

Affect experienced during an exercise session is purported to predict future exercise behaviour. Compared to continuous moderate-intensity exercise (CMI), the affective response to continuous vigorous-intensity exercise (CVI) has consistently been shown to be more aversive. The affective response, and overall tolerability to high-intensity interval training (HIT), is less studied. To date, there has yet to be a comparison between HIT, CVI, and CMI. The purpose of this study was to compare the tolerability and affective responses during HIT to CVI and CMI. This study utilized a repeated measures, randomized, counter-balanced design. Forty-four participants visited the laboratory on four occasions. Baseline fitness testing was conducted to establish peak power output in Watts (W peak). Three subsequent visits involved a single bout of a) HIT, corresponding to 1-minute at ∼ 100% W peak and 1-minute at ∼ 20% W peak for 20 minutes, b) CMI, corresponding to ∼ 40% W peak for 40 minutes, and c) CVI, corresponding to ∼ 80% W peak for 20 minutes. The order of the sessions was randomized. Affective responses were measured before, during and after each session. Task self-efficacy, intentions, enjoyment and preference were measured after sessions. Participants reported greater enjoyment of HIT as compared to CMI and CVI, with over 50% of participants reporting a preference to engage in HIT as opposed to either CMI or CVI. HIT was considered more pleasurable than CVI after exercise, but less pleasurable than CMI at these times. Despite this participants reported being just as confident to engage in HIT as they were CMI, but less confident to engage in CVI. This study highlights the utility of HIT in inactive individuals, and suggests that it may be a viable alternative to traditionally prescribed continuous modalities of exercise for promoting self-efficacy and enjoyment of exercise.

Where Does HIT Fit? An Examination of the Affective Response to High-Intensity Intervals in Comparison to Continuous Moderate- and Continuous Vigorous-Intensity Exercise in the Exercise Intensity-Affect Continuum

PubMed Central

Jung, Mary E.; Bourne, Jessica E.; Little, Jonathan P.

2014-01-01

Affect experienced during an exercise session is purported to predict future exercise behaviour. Compared to continuous moderate-intensity exercise (CMI), the affective response to continuous vigorous-intensity exercise (CVI) has consistently been shown to be more aversive. The affective response, and overall tolerability to high-intensity interval training (HIT), is less studied. To date, there has yet to be a comparison between HIT, CVI, and CMI. The purpose of this study was to compare the tolerability and affective responses during HIT to CVI and CMI. This study utilized a repeated measures, randomized, counter-balanced design. Forty-four participants visited the laboratory on four occasions. Baseline fitness testing was conducted to establish peak power output in Watts (Wpeak). Three subsequent visits involved a single bout of a) HIT, corresponding to 1-minute at ∼100% Wpeak and 1-minute at ∼20% Wpeak for 20 minutes, b) CMI, corresponding to ∼40% Wpeak for 40 minutes, and c) CVI, corresponding to ∼80% Wpeak for 20 minutes. The order of the sessions was randomized. Affective responses were measured before, during and after each session. Task self-efficacy, intentions, enjoyment and preference were measured after sessions. Participants reported greater enjoyment of HIT as compared to CMI and CVI, with over 50% of participants reporting a preference to engage in HIT as opposed to either CMI or CVI. HIT was considered more pleasurable than CVI after exercise, but less pleasurable than CMI at these times. Despite this participants reported being just as confident to engage in HIT as they were CMI, but less confident to engage in CVI. This study highlights the utility of HIT in inactive individuals, and suggests that it may be a viable alternative to traditionally prescribed continuous modalities of exercise for promoting self-efficacy and enjoyment of exercise. PMID:25486273

Reliability and day-to-day variability of peak fat oxidation during treadmill ergometry.

PubMed

De Souza Silveira, Raul; Carlsohn, Anja; Langen, Georg; Mayer, Frank; Scharhag-Rosenberger, Friederike

2016-01-01

Exercising at intensities where fat oxidation rates are high has been shown to induce metabolic benefits in recreational and health-oriented sportsmen. The exercise intensity (Fatpeak) eliciting peak fat oxidation rates is therefore of particular interest when aiming to prescribe exercise for the purpose of fat oxidation and related metabolic effects. Although running and walking are feasible and popular among the target population, no reliable protocols are available to assess Fatpeak as well as its actual velocity (VPFO) during treadmill ergometry. Our purpose was therefore, to assess the reliability and day-to-day variability of VPFO and Fatpeak during treadmill ergometry running. Sixteen recreational athletes (f = 7, m = 9; 25 ± 3 y; 1.76 ± 0.09 m; 68.3 ± 13.7 kg; 23.1 ± 2.9 kg/m(2)) performed 2 different running protocols on 3 different days with standardized nutrition the day before testing. At day 1, peak oxygen uptake (VO2peak) and the velocities at the aerobic threshold (VLT) and respiratory exchange ratio (RER) of 1.00 (VRER) were assessed. At days 2 and 3, subjects ran an identical submaximal incremental test (Fat-peak test) composed of a 10 min warm-up (70 % VLT) followed by 5 stages of 6 min with equal increments (stage 1 = VLT, stage 5 = VRER). Breath-by-breath gas exchange data was measured continuously and used to determine fat oxidation rates. A third order polynomial function was used to identify VPFO and subsequently Fatpeak. The reproducibility and variability of variables was verified with an intraclass correlation coefficient (ICC), Pearson's correlation coefficient, coefficient of variation (CV) and the mean differences (bias) ± 95 % limits of agreement (LoA). ICC, Pearson's correlation and CV for VPFO and Fatpeak were 0.98, 0.97, 5.0 %; and 0.90, 0.81, 7.0 %, respectively. Bias ± 95 % LoA was -0.3 ± 0.9 km/h for VPFO and -2 ± 8 % of VO2peak for Fatpeak. In summary, relative and absolute reliability indicators for VPFO and Fatpeak were found to be excellent. The observed LoA may now serve as a basis for future training prescriptions, although fat oxidation rates at prolonged exercise bouts at this intensity still need to be investigated.

Maternal Perceptions of Infant Exercise in the Neonatal Intensive Care Unit

PubMed Central

Gravem, Dana; Lakes, Kimberley D.; Teran, Lorena; Rich, Julia; Cooper, Dan; Olshansky, Ellen

2013-01-01

Objective To identify important factors that influence mothers’ perceptions of engaging in exercise with their preterm infants. Design Qualitative, semistructured individual interviews. Setting Neonatal Intensive Care Unit. Participants Thirteen mothers of preterm infants who were in the Neonatal Intensive Care Unit. Methods Two researchers conducted interviews with mothers in English or Spanish. Interviews were recorded, transcribed, and analyzed. Results Mothers tended to view infant exercise as beneficial but feared for the safety of their infants. They perceived nurses as experts who could safely exercise their infants but feared that they themselves might harm their infants. Factors that influenced their beliefs included previous experiences with infant exercise and views regarding the fragility or the strength of their own infants. Mothers identified nurses, doctors, family members, and research studies as trusted sources of information on exercise efficacy and safety. Conclusion Understanding and addressing mothers’ perceptions is a crucial component of a nursing intervention that teaches parents to do assisted exercises at home with their preterm infants. PMID:19883474

An acute bout of localized resistance exercise can rapidly improve inhibitory control

PubMed Central

Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Takeuchi, Tatsuya; Tanaka, Daichi; Hamaoka, Takafumi; Hashimoto, Takeshi; Isaka, Tadao

2017-01-01

The positive effect of acute resistance exercise on executive function, such as inhibitory control (IC), is poorly understood. Several previous studies have demonstrated this effect using whole-body resistance exercise. However, it remains unclear whether localized resistance exercise performed using only limited muscle groups could also acutely improve IC. Thus, the present study examined the effect of an acute bout of localized resistance exercise on IC. Twelve healthy men performed a color-word Stroop task (CWST) before and immediately after the experimental conditions, which consisted of 2 resistance exercises and a resting control (CON). Bilateral knee extension was used to create 2 resistance exercise conditions: light-intensity resistance exercise (LRE) and high-intensity resistance exercise (HRE) conditions, which were 40% and 80% of one-repetition maximum, respectively. The resistance exercise session was programmed for 6 sets with 10 repetitions per set. The CWST-measured IC was significantly improved immediately after both LRE and HRE, but it did not improve immediately after CON. However, the improved IC was significantly greater in HRE than in LRE. The present findings showed that IC could be rapidly improved by an acute bout of localized resistance exercise, especially with high-intensity. Therefore, we suggest that in addition to whole-body resistance exercise, localized resistance exercise performed using limited muscle groups may be sufficient for improving IC. PMID:28877232

Metabolic syndrome and hypertension: regular exercise as part of lifestyle management.

PubMed

Lackland, Daniel T; Voeks, Jenifer H

2014-11-01

The incorporation of physical activity and exercise represents a clinically important aspect in the management of metabolic syndrome, hypertension, and diabetes. While the benefit of exercise and active lifestyles is well documented for prevention and risk reduction of cardiovascular and stroke outcomes, the detailed regiment and recommendations are less clear. The components of a prescribed physical activity include consideration of activity type, frequency of an activity, activity duration, and intensity of a specific physical movement. The exercise parameters prescribed as part of the management of metabolic syndrome, diabetes, and elevated blood pressure are most often proposed as separate documents while the general recommendations are similar. The evidence is strong such that physical activity and exercise recommendations in disease management guidelines are considered high quality. The general recommendations for both blood pressure and glycemic management include a regiment of physical activity with moderate- to high-intensity exercise of 30-min bouts on multiple days with a desired goal of a total of 150 min of exercise per week. While additional research is needed to identify the specific exercise/activity mode, frequencies for exercise training, intensity levels, and duration of exercise that achieve maximal blood pressure and glycemic lowering, this general recommendation showed a consistent and significant benefit in risk reduction. Similarly, the current available evidence also indicates that aerobic exercise, dynamic resistance exercise, and isometric exercises can lower blood pressure and improve glycemic control.

The Positive Effects of Priming Exercise on Oxygen Uptake Kinetics and High-Intensity Exercise Performance Are Not Magnified by a Fast-Start Pacing Strategy in Trained Cyclists

PubMed Central

Caritá, Renato Aparecido Corrêa; Greco, Camila Coelho; Denadai, Benedito Sérgio

2014-01-01

The purpose of this study was to determine both the independent and additive effects of prior heavy-intensity exercise and pacing strategies on the VO2 kinetics and performance during high-intensity exercise. Fourteen endurance cyclists (VO2max  = 62.8±8.5 mL.kg−1.min−1) volunteered to participate in the present study with the following protocols: 1) incremental test to determine lactate threshold and VO2max; 2) four maximal constant-load tests to estimate critical power; 3) six bouts of exercise, using a fast-start (FS), even-start (ES) or slow-start (SS) pacing strategy, with and without a preceding heavy-intensity exercise session (i.e., 90% critical power). In all conditions, the subjects completed an all-out sprint during the final 60 s of the test as a measure of the performance. For the control condition, the mean response time was significantly shorter (p<0.001) for FS (27±4 s) than for ES (32±5 s) and SS (32±6 s). After the prior exercise, the mean response time was not significantly different among the paced conditions (FS = 24±5 s; ES = 25±5 s; SS = 26±5 s). The end-sprint performance (i.e., mean power output) was only improved (∼3.2%, p<0.01) by prior exercise. Thus, in trained endurance cyclists, an FS pacing strategy does not magnify the positive effects of priming exercise on the overall VO2 kinetics and short-term high-intensity performance. PMID:24740278

Impact of High-intensity Intermittent and Moderate-intensity Continuous Exercise on Autonomic Modulation in Young Men.

PubMed

Cabral-Santos, C; Giacon, T R; Campos, E Z; Gerosa-Neto, J; Rodrigues, B; Vanderlei, L C M; Lira, F S

2016-06-01

The aim of this study was to compare heart rate variability (HRV) recovery after two iso-volume (5 km) exercises performed at different intensities. 14 subjects volunteered (25.17±5.08 years; 74.7±6.28 kg; 175±0.05 cm; 59.56±5.15 mL·kg(-1)·min(-1)) and after determination of peak oxygen uptake (VO2Peak) and the speed associated with VO2Peak (sVO2Peak), the subjects completed 2 random experimental trials: high-intensity exercise (HIE - 1:1 at 100% sVO2Peak), and moderate-intensity continuous exercise (MIE - 70% sVO2Peak). HRV and RR intervals were monitored before, during and after the exercise sessions together with, the HRV analysis in the frequency domains (high-frequency - HF: 0.15 to 0.4 Hz and low-frequency - LF: 0.04 to 0.15 Hz components) and the ratio between them (LF/HF). Statistical analysis comparisons between moments and between HIE and MIE were performed using a mixed model. Both exercise sessions modified LFlog, HFlog, and LF/HF (F=16.54, F=19.32 and F=5.17, p<0.05, respectively). A group effect was also found for LFlog (F=23.91, p<0.05), and HFlog (F=57.55, p< 0.05). LF/HF returned to resting value 15 min after MIE exercise and 20 min after HIE exercise. This means that the heavy domain (aerobic and anaerobic threshold) induces dissimilar autonomic modification in physically active subjects. Both HIE and MIE modify HRV, and generally HIE delays parasympathetic autonomic modulation recovery after iso-volume exercise. © Georg Thieme Verlag KG Stuttgart · New York.

Exploiting significance of physical exercise in prevention of gastrointestinal disorders.

PubMed

Bilski, Jan; Mazur-Bialy, Agnieszka; Magierowski, Marcin; Kwiecien, Slawomir; Wojcik, Dagmara; Ptak-Belowska, Agata; Surmiak, Marcin; Targosz, Aneta; Magierowska, Katarzyna; Brzozowski, Tomasz

2018-05-21

Physical activity can be involved in the prevention of gastrointestinal (GI)-tract diseases, however, the results regarding the volume and the intensity of exercise considered as beneficial for protection of gastrointestinal organs are conflicting. The main objective of this review is to provide a comprehensive and updated overview on the beneficial and harmful effects of physical activity on the gastrointestinal tract. We attempted to discuss recent evidence regarding the association between different modes and intensity levels of exercise and physiological functions of the gut and gut pathology. The regular, moderate exercise can exert a beneficial effect on GI-tract disorders such as reflux esophagitis, peptic ulcers, cholelithiasis, constipation and inflammatory bowel disease (IBD) leading to the attenuation of the symptoms. This voluntary exercise has been shown to reduce the risk of colorectal cancer. On the other hand, there is considerable evidence that the high-intensity training or prolonged endurance training can exert a negative influence on GI-tract resulting in the exacerbation of symptoms. Physical activity can exhibit a beneficial effect on a variety of gastrointestinal diseases, however, this effect depends upon the exercise mode, duration and intensity. The accumulated evidence indicate that management of gastrointestinal problems and their relief by the exercise seems to be complicated and require adjustments of physical activity training, dietary measures and medical monitoring of symptoms. More experimental and clinical studies on the effects of physical activity on GI-tract disorders are warranted. Especially, the association between the exercise intensity and data addressing the underlying mechanism(s) of the exercise as the complementary therapy in the treatment of gastrointestinal disorders, require further determination in animal models and humans. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Association between exercise intensity and renal blood flow evaluated using ultrasound echo.

PubMed

Kawakami, Shotaro; Yasuno, Tetsuhiko; Matsuda, Takuro; Fujimi, Kanta; Ito, Ai; Yoshimura, Saki; Uehara, Yoshinari; Tanaka, Hiroaki; Saito, Takao; Higaki, Yasuki

2018-03-10

High-intensity exercise reduces renal blood flow (RBF) and may transiently exacerbate renal dysfunction. RBF has previously been measured invasively by administration of an indicator material; however, non-invasive measurement is now possible with technological innovations. This study examined variations in RBF at different exercise intensities using ultrasound echo. Eight healthy men with normal renal function (eGFR cys 114 ± 19 mL/min/1.73 m 2 ) participated in this study. Using a bicycle ergometer, participants underwent an incremental exercise test using a ramp protocol (20 W/min) until exhaustion in Study 1 and the lactate acid breaking point (LaBP) was calculated. Participants underwent a multi-stage test at exercise intensities of 60, 80, 100, 120, and 140% LaBP in Study 2. RBF was measured by ultrasound echo at rest and 5 min after exercise in Study 1 and at rest and immediately after each exercise in Study 2. To determine the mechanisms behind RBF decline, a catheter was placed into the antecubital vein to study vasoconstriction dynamics. RBF after maximum exercise decreased by 51% in Study 1. In Study 2, RBF showed no significant decrease until 80% LaBP, and showed a significant decrease (31%) at 100% LaBP compared with at rest (p < 0.01). The sympathetic nervous system may be involved in this reduction in RBF. RBF showed no significant decrease until 80% LaBP, and decreased with an increase in blood lactate. Reduction in RBF with exercise above the intensity at LaBP was due to decreased cross-sectional area rather than time-averaged flow velocity.

Effects of high-intensity exercise and protein supplement on muscle mass in ADL dependent older people with and without malnutrition: a randomized controlled trial.

PubMed

Carlsson, M; Littbrand, H; Gustafson, Y; Lundin-Olsson, L; Lindelöf, N; Rosendahl, E; Håglin, L

2011-08-01

Loss of muscle mass is common among old people living in institutions but trials that evaluate interventions aimed at increasing the muscle mass are lacking. Objective, participants and intervention: This randomized controlled trial was performed to evaluate the effect of a high-intensity functional exercise program and a timed protein-enriched drink on muscle mass in 177 people aged 65 to 99 with severe physical or cognitive impairments, and living in residential care facilities. Three-month high-intensity exercise was compared with a control activity and a protein-enriched drink was compared with a placebo drink. A bioelectrical impedance spectrometer (BIS) was used in the evaluation. The amount of muscle mass and body weight (BW) were followed-up at three and six months and analyzed in a 2 x 2 factorial ANCOVA, using the intention to treat principle, and controlling for baseline values. At 3-month follow-up there were no differences in muscle mass and BW between the exercise and the control group or between the protein and the placebo group. No interaction effects were seen between the exercise and nutritional intervention. Long-term negative effects on muscle mass and BW was seen in the exercise group at the 6-month follow-up. A three month high-intensity functional exercise program did not increase the amount of muscle mass and an intake of a protein-enriched drink immediately after the exercise did not induce any additional effect on muscle mass. There were negative long-term effects on muscle mass and BW, indicating that it is probably necessary to compensate for an increased energy demand when offering a high-intensity exercise program.

Effects of active recovery on autonomic and haemodynamic responses after aerobic exercise.

PubMed

Soares, Antonio H G; Oliveira, Tiago P; Cavalcante, Bruno R; Farah, Breno Q; Lima, Aluísio H R A; Cucato, Gabriel G; Cardoso, Crivaldo G; Ritti-Dias, Raphael M

2017-01-01

The aim of this study was to examine the effect of active recovery on autonomic and haemodynamic responses after exercise in healthy adults. Nineteen healthy young male individuals underwent two experimental sessions: exercise with active recovery (AR) and exercise with passive recovery (PR). The exercise sessions comprised three phases: warm-up (5 min), exercise phase (cycle ergometer, 30 min, intensity between 60 and 70% of the heart rate reserve) and recovery (5 min). In the AR, the subjects remained cycling in the recovery phase at intensity between 30% and 35% of heart rate reserve, while in the PR, the subjects stopped the exercise after finishing the exercise phase. Blood pressure and heart rate were measured before and over the 30 min after the interventions. There were no differences for systolic and diastolic blood pressures, heart rate and rate pressure product between active and passive recovery sessions. Also, all heart rate variability parameters changed similarly after exercise with passive or active recovery sessions. In summary, exercise with active recovery does not affect the autonomic and haemodynamic responses after moderate-intensity aerobic exercise in healthy young male individuals. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Ergogenic effects of caffeine and sodium bicarbonate supplementation on intermittent exercise performance preceded by intense arm cranking exercise.

PubMed

Marriott, Matthaus; Krustrup, Peter; Mohr, Magni

2015-01-01

Caffeine and sodium bicarbonate ingestion have been suggested to improve high-intensity intermittent exercise, but it is unclear if these ergogenic substances affect performance under provoked metabolic acidification. To study the effects of caffeine and sodium bicarbonate on intense intermittent exercise performance and metabolic markers under exercise-induced acidification, intense arm-cranking exercise was performed prior to intense intermittent running after intake of placebo, caffeine and sodium bicarbonate. Male team-sports athletes (n = 12) ingested sodium bicarbonate (NaHCO3; 0.4 g.kg(-1) b.w.), caffeine (CAF; 6 mg.kg(-1) b.w.) or placebo (PLA) on three different occasions. Thereafter, participants engaged in intense arm exercise prior to the Yo-Yo intermittent recovery test level-2 (Yo-Yo IR2). Heart rate, blood lactate and glucose as well as rating of perceived exertion (RPE) were determined during the protocol. CAF and NaHCO3 elicited a 14 and 23% improvement (P < 0.05), respectively, in Yo-Yo IR2 performance, post arm exercise compared to PLA. The NaHCO3 trial displayed higher [blood lactate] (P < 0.05) compared to CAF and PLA (10.5 ± 1.9 vs. 8.8 ± 1.7 and 7.7 ± 2.0 mmol.L(-1), respectively) after the Yo-Yo IR2. At exhaustion CAF demonstrated higher (P < 0.05) [blood glucose] compared to PLA and NaHCO3 (5.5 ± 0.7 vs. 4.2 ± 0.9 vs. 4.1 ± 0.9 mmol.L(-1), respectively). RPE was lower (P < 0.05) during the Yo-Yo IR2 test in the NaHCO3 trial in comparison to CAF and PLA, while no difference in heart rate was observed between trials. Caffeine and sodium bicarbonate administration improved Yo-Yo IR2 performance and lowered perceived exertion after intense arm cranking exercise, with greater overall effects of sodium bicarbonate intake.

Effect of Training Status on Oxygen Consumption in Women After Resistance Exercise.

PubMed

Benton, Melissa J; Waggener, Green T; Swan, Pamela D

2016-03-01

This study compared acute postexercise oxygen consumption in 11 trained women (age, 46.5 ± 1.6 years; body mass index [BMI], 28.4 ± 1.7 kg·m(-2) and 11 untrained women (age, 46.5 ± 1.5 years; BMI, 27.5 ± 1.5 kg·m(-2)) after resistance exercise (RE). Resistance exercise consisted of 3 sets of 8 exercises (8-12 repetitions at 50-80% 1 repetition maximum). Oxygen consumption (VO2 ml·min(-1)) was measured before and after (0, 20, 40, 60, 90, and 120 minutes) RE. Immediately after cessation of RE (time 0), oxygen consumption increased in both trained and untrained women and remained significantly above baseline through 60 minutes after exercise (p < 0.01). Total oxygen consumption during recovery was 31.3 L in trained women and 27.4 L in untrained women (p = 0.07). In trained women, total oxygen consumption was strongly related to absolute (kg) lean mass (r = 0.88; p < 0.001), relative (kilogram per square meter) lean mass (r = 0.91; p < 0.001), and duration of exercise (r = 0.68; p ≤ 0.05), but in untrained women, only training volume-load was related to total oxygen consumption (r = 0.67; p ≤ 0.05). In trained women, 86% of the variance in oxygen consumption was explained by lean mass and exercise duration, whereas volume-load explained 45% in untrained women. Our findings suggest that, in women, resistance training increases metabolic activity of lean tissue. Postexercise energy costs of RE are determined by the duration of stimulation provided by RE rather than absolute work (volume-load) performed. This phenomenon may be related to type II muscle fibers and increased protein synthesis.

Exercise countermeasures for long-duration spaceflight: muscle- and intensity-specific considerations

NASA Astrophysics Data System (ADS)

Trappe, Todd

2012-07-01

On-orbit and ground-based microgravity simulation studies have provided a wealth of information regarding the efficacy of exercise countermeasures for protecting skeletal muscle and cardiovascular function during long-duration spaceflights. While it appears that exercise will be the central component to maintaining skeletal muscle and cardiovascular health of astronauts, the current exercise prescription is not completely effective and is time consuming. This lecture will focus on recent exercise physiology studies examining high intensity, low volume exercise in relation to muscle specific and cardiovascular health. These studies provide the basis of the next generation exercise prescription currently being implemented during long-duration space missions on the International Space Station.

Primary prevention in patients with a strong family history of coronary heart disease.

PubMed

Burke, Lora A

2003-01-01

The interplay of genetic and environmental factors places first-degree relatives of individuals with premature coronary heart disease at greater risk of developing the disease than the general population. Disease processes, such as dyslipidemia, hypertension, and glucose and insulin metabolism, and lifestyle habits, such as eating and exercise patterns, as well as socioeconomic status aggregate in families with coronary heart disease. The degree of risk associated with a family history varies with the degree of relationship and the age at onset of disease. All individuals with a family history of premature heart disease should have a thorough coronary risk assessment performed, which can be initiated in an office visit. Absolute risk for coronary heart disease determination will predict the intensity of preventive interventions. This article reviews the components of risk determination and primary prevention in individuals with a strong family history of coronary heart disease.

Acute effects of aerobic exercise on mood and hunger feelings in male obese adolescents: a crossover study.

PubMed

Lofrano-Prado, Mara Cristina; Hill, James O; Silva, Humberto José Gomes; Freitas, Camila Rodrigues Menezes; Lopes-de-Souza, Sandra; Lins, Tatiana Acioli; do Prado, Wagner Luiz

2012-04-03

The aim of this study was to determine the acute effects of exercise intensity on anxiety, mood states and hunger in obese adolescents. Subjects were eight male obese adolescents (age 15.44 ± 2.06 y; BMI 33.06 ± 4.78 kg/m2). Each subject underwent three experimental trials: (1) Control, seated for 30 min; (2) Low intensity exercise (LIE)--exercise at 10% below ventilatory threshold (VT); (3) High intensity exercise (HIE)--exercise at 10% above VT. Anxiety (STAI Trait/State), mood (POMS) and hunger (VAS) were assessed before and immediately after the experimental sessions. Comparisons between trials and times were assessed using Kruskal-Wallis and Wilcoxon tests, respectively. Associations between variables were described using a Spearman test. The largest increase in hunger was observed after LEI (914.22%). Both exercise sessions increased anxiety, fatigue and decreased vigor (p < 0.05). Acute exercise bouts are associated with negative changes in anxiety and mood, and with increases in hunger in obese adolescents.

Effect of high-intensity intermittent swimming training on fatty acid oxidation enzyme activity in rat skeletal muscle.

PubMed

Terada, Shin; Tabata, Izumi; Higuchi, Mitsuru

2004-02-01

We previously reported that high-intensity exercise training significantly increased citrate synthase (CS) activity, a marker of oxidative enzyme, in rat skeletal muscle to a level equaling that attained after low-intensity prolonged exercise training (Terada et al., J Appl Physiol 90: 2019-2024, 2001). Since mitochondrial oxidative enzymes and fatty acid oxidation (FAO) enzymes are often increased simultaneously, we assessed the effect of high-intensity intermittent swimming training on FAO enzyme activity in rat skeletal muscle. Male Sprague-Dawley rats (3 to 4 weeks old) were assigned to a 10-day period of high-intensity intermittent exercise training (HIT), low-intensity prolonged exercise training (LIT), or sedentary control conditions. In the HIT group, the rats repeated fourteen 20 s swimming sessions with a weight equivalent to 14-16% of their body weight. Between the exercise sessions, a 10 s pause was allowed. Rats in the LIT group swam 6 h/day in two 3 h sessions separated by 45 min of rest. CS activity in the triceps muscle of rats in the HIT and LIT groups was significantly higher than that in the control rats by 36 and 39%, respectively. Furthermore, 3-beta hydroxyacyl-CoA dehydrogenase (HAD) activity, an important enzyme in the FAO pathway in skeletal muscle, was higher in the two training groups than in the control rats (HIT: 100%, LIT: 88%). No significant difference in HAD activity was observed between the two training groups. In conclusion, the present investigation demonstrated that high-intensity intermittent swimming training elevated FAO enzyme activity in rat skeletal muscle to a level similar to that attained after 6 h of low-intensity prolonged swimming exercise training.

Absolute hypoxic exercise training enhances in vitro thrombin generation by increasing procoagulant platelet-derived microparticles under high shear stress in sedentary men.

PubMed

Chen, Yu-Wen; Chen, Yi-Ching; Wang, Jong-Shyan

2013-05-01

HS (high shear) stress associated with artery stenosis facilitates TG (thrombin generation) by increasing the release of procoagulant PDMPs (platelet-derived microparticles). Physical exercise and hypoxia may paradoxically modulate vascular thrombotic risks. The aim of the present study was to investigate how exercise training with/without hypoxia affected TG mediated by PDMPs under physio-pathological shear flows. A total of 75 sedentary males were randomly divided into five groups (n=15 in each group): 21% O2 [NC (normoxic control)] or 15% O2 [HC (hypoxic control)] at rest or were trained at 50% of peak work rate under 21% O2 [NT (normoxic training)] or 15% O2 [HAT (hypoxic-absolute training)], or 50% of HR (heart rate) reserve under 15% O2 [HRT (hypoxic-relative training)] for 30 min/day, 5 days/week for 4 weeks. The PDMP characteristics and dynamic TG were measured by flow cytometry and thrombinography respectively. Before the intervention, strenuous exercise markedly increased the PDMP count (14.8%) and TG rate (19.5%) in PDMP-rich plasma at 100 dynes/cm2 of shear stress (P<0.05). After the interventions, both NT and HRT significantly attenuated the enhancement of HS-induced PDMPs (4.7 and 4.9%) and TG rate (3.8 and 3.0%) (P<0.05) by severe exercise. Conversely, HAT notably promoted the PDMP count (37.3%) and TG rate (38.9%) induced by HS (P<0.05), concurrent with increasing plasma TF (tissue factor) and coagulation factor V levels at rest or following exercise. We conclude that both HRT and NT depress similarly HS-mediated TG during exercise, but HAT accelerates the prothrombotic response to vigorous exercise. These findings provide new insights into how exercise training under a hypoxic condition influences the risk of thrombosis associated with stenotic arteries.

Effect of static and dynamic exercise on heart rate and blood pressure variabilities.

PubMed

González-Camarena, R; Carrasco-Sosa, S; Román-Ramos, R; Gaitán-González, M J; Medina-Bañuelos, V; Azpiroz-Leehan, J

2000-10-01

This study examines the effect of static and dynamic leg exercises on heart rate variability (HRV) and blood pressure variability (BPV) in humans. 10 healthy male subjects were studied at rest, during static exercise performed at 30% of maximal voluntary contraction (SX30), and during dynamic cycling exercises done at 30% of VO2max (DX30) and at 60% of VO2max (DX60). Respiration, heart rate, and blood pressure signals were digitized to analyze temporal and spectral parameters involving short and overall indexes (SD, deltaRANGE, RMSSD, Total power), power of the low (LF), middle (MF), and high (HF) frequency components, and the baroreceptor sensitivity by the alphaMF index. During SX30, indexes of HRV as SD, deltaRANGE, Total power, and MF in absolute units increased in relation with rest values and were significantly higher (P < 0.001) than during DX30 and DX60; HF during SX30, in normalized and absolute units, was not different of the rest condition but was higher (P < 0.001) than HF during DX30 and DX60. Parameters of BPV as SD and deltaRANGE increased (P < 0.001) during both type of exercises, and significant (P < 0.01) increments were observed on MF during SX30 and DX30; systolic HF was attenuated during DX30 (P < 0.05), whereas diastolic HF was augmented during DX60 (P < 0.001). Compared with rest condition, the alphaMF index decreased (P < 0.01) only during dynamic exercises. Because HRV and BPV response is different when induced by static or dynamic exercise, differences in the autonomic activity can be advised. Instead of the vagal withdrawal and sympathetic augmentation observed during dynamic exercise, the increase in the overall HRV and the MF component during static exercise suggest an increased activity of both autonomic branches.

The function of androgen/androgen receptor and insulin growth factor‑1/insulin growth factor‑1 receptor on the effects of Tribulus terrestris extracts in rats undergoing high intensity exercise.

PubMed

Wu, Yin; Yang, Hongfang; Wang, Xiaohui

2017-09-01

Our previous study demonstrated that treatment with Tribulus terrestris (TT) extracts (120 mg/kg) promoted the muscle weight gain and performance of rats undergoing high intensity exercise. The present study was designed to explore the mechanisms underlying the effect of treatment with TT extracts and the involvement of androgens, the androgen receptor (AR), insulin growth factor‑1 (IGF‑1) and the IGF‑1 receptor (IGF‑1R). A total of 32 Sprague‑Dawley rats were randomly divided into groups as follows: Control; TT, treated with TT extracts, E, high intensity exercise; E+TT, high intensity exercise plus TT treatment. The rats of the E and E+TT groups underwent high intensity exercise with a progressively increasing load for 5 weeks, and TT extracts were intragastrically administered in the TT and E+TT rats 30 min prior to training. TT extract composition was analyzed using ultra‑high performance liquid chromatography‑quadrupole‑time of flight mass spectrometry. Testosterone and IGF‑1 plasma levels and AR, IGF‑1R and myosin heavy chain (MHC) protein levels in muscles were determined by ELISA and western blotting, respectively. The saponins tigogenin and diosgenin comprised ~71.35% of the total peak area. Compared with the E group, TT extracts increased the testosterone and IGF‑1 plasma levels, and AR, IGF‑1R and MHC protein levels in the gastrocnemius of rats undergoing high intensity exercise, accompanied with increased body weight and gastrocnemius weight. In conclusion, the effect of TT extracts on the performance of high intensity exercise rats may be attributed to increased levels of circulating testosterone and IGF‑1 and increased AR and IGF‑1R protein expression levels in the gastrocnemius, resulting in increased muscle weight and increased MHC in the gastrocnemius. The present study provided preliminary evidence supporting the use of TT extracts as a dietary supplement for the promotion of skeletal muscle mass increase and the enhancement of athletic performance in humans performing high intensity exercise.

The Role of Macronutrients in Exercise.

ERIC Educational Resources Information Center

Arterberry, Christopher M.

2002-01-01

Explores the role of macronutrients in exercise, examining research pertaining to exercise intensity, exercise duration, macronutrient intake, and mode of exercise as they pertain to both athletes and recreational exercisers. The paper explains that coaches and trainers must interpret and apply research findings to individual exercisers,…

Influence of Goal Contents on Exercise Addiction: Analysing the Mediating Effect of Passion for Exercise

PubMed Central

Sicilia, Álvaro; Alcaraz-Ibáñez, Manuel; Lirola, María-Jesús; Burgueño, Rafael

2017-01-01

Abstract Based on the self-determination theory (Deci and Ryan, 1985, 2000), the purpose of this study was to examine the effects of exercise goal contents on exercise addiction, taking into account the mediating effects of passion for exercise. A total of 384 university students (284 men and 100 women; Mage = 20.31, SD = 3.10) completed a questionnaire that measured exercise frequency and intensity, exercise goal contents (e.g. intrinsic: social affiliation, health management, skill development; extrinsic: image and social recognition), passion for exercise (e.g. harmonious and obsessive), and exercise addiction. After controlling the exercise frequency and intensity effects, results showed that goal contents did not directly predict exercise addiction. However, mediation analysis showed that goal contents predicted addiction through passion for exercise. These results support a motivational sequence in which extrinsic versus intrinsic goals influence exercise addiction because such goals are positively associated with obsessive passion for exercise and negatively associated with harmonious passion. PMID:29134055

Influence of Goal Contents on Exercise Addiction: Analysing the Mediating Effect of Passion for Exercise.

PubMed

Sicilia, Álvaro; Alcaraz-Ibáñez, Manuel; Lirola, María-Jesús; Burgueño, Rafael

2017-10-01

Based on the self-determination theory (Deci and Ryan, 1985, 2000), the purpose of this study was to examine the effects of exercise goal contents on exercise addiction, taking into account the mediating effects of passion for exercise. A total of 384 university students (284 men and 100 women; M age = 20.31, SD = 3.10) completed a questionnaire that measured exercise frequency and intensity, exercise goal contents (e.g. intrinsic: social affiliation, health management, skill development; extrinsic: image and social recognition), passion for exercise (e.g. harmonious and obsessive), and exercise addiction. After controlling the exercise frequency and intensity effects, results showed that goal contents did not directly predict exercise addiction. However, mediation analysis showed that goal contents predicted addiction through passion for exercise. These results support a motivational sequence in which extrinsic versus intrinsic goals influence exercise addiction because such goals are positively associated with obsessive passion for exercise and negatively associated with harmonious passion.

Effects of intensity and duration of exercise on muscular responses to training of thoroughbred racehorses.

PubMed

Rivero, José-Luis L; Ruz, Antonio; Martí-Korff, Silvia; Estepa, José-Carlos; Aguilera-Tejero, Escolástico; Werkman, Jutta; Sobotta, Mathias; Lindner, Arno

2007-05-01

This study examined the effects of the intensity and duration of exercise on the nature and magnitude of training adaptations in muscle of adolescent (2-3 yr old) racehorses. Six thoroughbreds that had been pretrained for 2 mo performed six consecutive conditioning programs of varying lactate-guided intensities [velocities eliciting blood lactate concentrations of 2.5 mmol/l (v2.5) and 4 mmol/l (v4), respectively] and durations (5, 15, 25 min). Pre- and posttraining gluteus muscle biopsies were analyzed for myosin heavy chain content, fiber-type composition, fiber size, capillarization, and fiber histochemical oxidative and glycolytic capabilities. Although training adaptations were similar in nature, they varied greatly in magnitude among the different training protocols. Overall, the use of v4 as the exercise intensity for 25 min elicited the most consistent training adaptations in muscle, whereas the minimal training stimulus that evoked any significant change was identified with exercises of 15 min at v2.5. Within this range, muscular adaptations showed significant trends to be proportional to the exercise load of specific training programs. Taken together, these data suggest that muscular adaptations to training in horses occur on a continuum that is based on the exercise intensity and duration of training. The practical implications of this study are that exercises for 15 to 25 min/day at velocities between v2.5 and v4 can improve in the short term (3 wk) the muscular stamina in thoroughbreds. However, exercises of 5-15 min at v4 are necessary to enhance muscular features related to strength (hypertrophy).

My gut feeling says rest: Increased intestinal permeability contributes to chronic diseases in high-intensity exercisers.

PubMed

Van Houten, Jason M; Wessells, Robert J; Lujan, Heidi L; DiCarlo, Stephen E

2015-12-01

Chronic diseases are the leading cause of death and disability worldwide, and many of these conditions are linked to chronic inflammation. One potential cause of chronic inflammation is an increased intestinal epithelial permeability. Recent studies have demonstrated that parasympathetic stimulation via the efferent abdominal vagus nerve increases the expression and proper localization of tight junction proteins and decreases intestinal epithelial permeability. This finding may provide a novel approach for treating and preventing many chronic conditions. Importantly, physical activity is associated with increased resting parasympathetic (vagal) activity and lower risk of chronic diseases. However, high intensity long duration exercise can be harmful to overall health. Specifically, individuals who frequently exercise strenuously and for longer time intervals have the same mortality rates as sedentary individuals. This may be explained, in part, by longer periods of reduced vagal activity as vagal activity is markedly reduced both during and after intense exercise. We hypothesize that one mechanism by which exercise provides its health benefits is by increasing resting vagal activity and decreasing intestinal epithelial permeability, thus decreasing chronic inflammation. Additionally, we hypothesize that long periods of reduced vagal activity in individuals who exercise at high intensities and for longer durations, decrease the integrity of the intestinal barrier, putting them at greater risk of chronic inflammation and a host of chronic diseases. Thus, this hypothesis provides a conceptual link between the well-established benefits of frequent exercise and the paradoxical deleterious effects of prolonged, high-intensity exercise without adequate rest. Copyright © 2015. Published by Elsevier Ltd.

Impact of a carbohydrate-electrolyte drink on ingestive behaviour, affect and self-selected intensity during recreational exercise after 24-h fluid restriction.

PubMed

Peacock, Oliver J; Thompson, Dylan; Stokes, Keith A

2013-01-01

This study examined the effects of a carbohydrate-electrolyte drink on voluntary fluid intake, affect and self-selected intensity during recreational exercise after fluid restriction. In a randomised counterbalanced design, ten physically active adults were dehydrated via a 24-h period of fluid restriction before completing two 20-min bouts of cardiovascular exercise, 20-min of resistance exercise and 20 min on a cycle ergometer at a self-selected intensity with ad libitum access to water (W) or a carbohydrate-electrolyte solution (CES). Fluid restriction induced hypohydration of ∼1.2% initial body mass. Fluid intake during exercise was greater with CES (2105 ± 363 vs. 1470 ± 429 mL; P<0.01) and resulted in more adequate hydration (-0.03 ± 0.65 vs. -1.26 ± 0.80%; P<0.01). Plasma glucose concentrations (4.48 ± 0.40 vs. 4.28 ± 0.32 mmol L(-1); P<0.01) and pleasure ratings (2.63 ± 1.17 vs. 1.81 ± 1.37; P<0.01) were greater with CES than W. Mean power output during exercise performed at a self-selected intensity was 5.6% greater with CES (171 ± 63 vs. 162 ± 60 W; P<0.05). In physically active adults performing a 'real-life' recreational exercise simulation, CES resulted in more adequate hydration and an enhanced affective experience that corresponded with an increase in self-selected exercise intensity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Protection of Lotus Seedpod Proanthocyanidins on Organs and Tissues under High-intensity Excercise

PubMed Central

Mengyan, Zhang

2015-01-01

Lotus seedpod proanthocyanidins (LSPC) as a kind of polyphenols is widely used in medicines, cosmetics, health products. High-intensity exercise can cause damage to the body's organs and tissues. Different doses of LSPC is given to mice to check the function of protect effect to the body's organs and tissues under high-intensity exercise. The hemoglobin (HB) content, red blood cell (RBC) number and white blood cell (WBC) number were tested for mice after exercise. The activity of superoxide dismutase (SOD) and the contents of glutathione (GSH) and malondialdehyde (MDA) in muscle and viscera were evaluated. The result showed that LSPC can effectively reduce inflammation reaction in the body of mice with high intensity exercise, alleviate oxidative stress-induced injury of tissues and organs, and execute protective function on skeletal muscle and cardiac muscle. And the LSPC could enhance myocardial anti-oxygen and enzymatic activity which suggests the protective effects of resveratrol against exercise-induced myocardial damage in mice. PMID:26998176

Incorporating yoga into an intense physical therapy program in someone with Parkinson's disease: a case report.

PubMed

Moriello, Gabriele; Denio, Christopher; Abraham, Megan; DeFrancesco, Danielle; Townsley, Jill

2013-10-01

The purpose of this case report was to document outcomes following an intense exercise program integrating yoga with physical therapy exercise in a male with Parkinson's disease. The participant performed an intense 1½-hour program (Phase A) incorporating strengthening, balance, agility and yoga exercises twice weekly for 12 weeks. He then completed a new home exercise program developed by the researchers (Phase B) for 12 weeks. His score on the Parkinson's Disease Questionnaire improved 16 points while his score on the High Level Mobility Assessment tool improved 11 points. There were also improvements in muscle length of several lower extremity muscles, in upper and lower extremity muscle strength, in dynamic balance and he continues to work full time 29 months later. There were no improvements in thoracic posture or aerobic power. This intense program was an effective dose of exercise for someone with Parkinson's disease and allowed him to continue to participate in work, leisure, and community activities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Recurrent exercise-induced rhabdomyolysis due to low intensity fitness exercise in a healthy young patient

PubMed Central

Karre, Premnath Reddy; Gujral, Jeetinder

2011-01-01

Rhabdomyolysis is an uncommon but life threatening condition that develops due to breakdown of muscle and release of intracellular components into the circulation. A 24-year-old man otherwise healthy was admitted to our hospital because of muscle aches and weakness as well as cola coloured urine developed 3 days after carrying out the low intensity exercise. Diagnosis of rhabdomyolysis was made with creatine kinase (CK) levels of 214 356 U/l. He was treated for a similar condition at age 21. A muscle biopsy was done and the findings were normal. Rhabdomyolysis can develop with low intensity exercise; thus, it be considered in healthy young people. Young people with recurrent rhabdomyolysis due to low intensity exercise, in the absence of obvious medical and physical causes, should be evaluated further to rule out uncommon metabolic diseases. Our case demonstrates that complications especially renal failure in patients with rhabdomyolysis do not correspond to CK levels. PMID:22700603

Recurrent exercise-induced rhabdomyolysis due to low intensity fitness exercise in a healthy young patient.

PubMed

Karre, Premnath Reddy; Gujral, Jeetinder

2011-04-01

Rhabdomyolysis is an uncommon but life threatening condition that develops due to breakdown of muscle and release of intracellular components into the circulation. A 24-year-old man otherwise healthy was admitted to our hospital because of muscle aches and weakness as well as cola coloured urine developed 3 days after carrying out the low intensity exercise. Diagnosis of rhabdomyolysis was made with creatine kinase (CK) levels of 214 356 U/l. He was treated for a similar condition at age 21. A muscle biopsy was done and the findings were normal. Rhabdomyolysis can develop with low intensity exercise; thus, it be considered in healthy young people. Young people with recurrent rhabdomyolysis due to low intensity exercise, in the absence of obvious medical and physical causes, should be evaluated further to rule out uncommon metabolic diseases. Our case demonstrates that complications especially renal failure in patients with rhabdomyolysis do not correspond to CK levels.

The higher exercise intensity and the presence of allele I of ACE gene elicit a higher post-exercise blood pressure reduction and nitric oxide release in elderly women: an experimental study.

PubMed

Santana, Hugo A P; Moreira, Sérgio R; Neto, Willson B; Silva, Carla B; Sales, Marcelo M; Oliveira, Vanessa N; Asano, Ricardo Y; Espíndola, Foued S; Nóbrega, Otávio T; Campbell, Carmen S G; Simões, Herbert G

2011-12-02

The absence of the I allele of the angiotensin converting enzyme (ACE) gene has been associated with higher levels of circulating ACE, lower nitric oxide (NO) release and hypertension. The purposes of this study were to analyze the post-exercise salivary nitrite (NO2-) and blood pressure (BP) responses to different exercise intensities in elderly women divided according to their ACE genotype. Participants (n = 30; II/ID = 20 and DD = 10) underwent three experimental sessions: incremental test - IT (15 watts workload increase/3 min) until exhaustion; 20 min exercise 90% anaerobic threshold (90% AT); and 20 min control session without exercise. Volunteers had their BP and NO2- measured before and after experimental sessions. Despite both intensities showed protective effect on preventing the increase of BP during post-exercise recovery compared to control, post-exercise hypotension and increased NO2- release was observed only for carriers of the I allele (p < 0.05). Genotypes of the ACE gene may exert a role in post-exercise NO release and BP response.

Effects of exercise on functional aerobic capacity in adults with fibromyalgia syndrome: A systematic review of randomized controlled trials.

PubMed

García-Hermoso, Antonio; Saavedra, Jose M; Escalante, Yolanda

2015-01-01

Patients with fibromyalgia present a reduced capacity of upper and lower limb physical performance and affect their independence in performing everyday activities. The purpose of the present systematic review was to summarize evidence for the effectiveness and structure of exercise programs on functional aerobic capacity in patients with fibromyalgia syndrome. Keyword searches were made of seven databases. The systematic review was limited to English language studies of people with FM that evaluated the effects of exercise programs on functional aerobic capacity (6-minute walk test). The criteria for inclusion were satisfied by 12 randomized controlled trial (RCT) studies. The main cumulative evidence indicates that the programs based on aerobic exercise alone and on aquatic exercises have large (effect size = 0.85) and moderate (effect size = 0.44) effects. Aerobic and aquatic exercises at the proper intensity favour the increased functional aerobic capacity of fibromyalgia patients; however, most works do not adequately detail the intensity of the exercises. Moderate intensity exercise (aerobic and aquatic exercise) performed at least two times per week and 30-60 minutes a day is effective for increasing functional aerobic capacity, favouring the daily activities of daily living in this population.

Hybrid diffuse optical techniques for continuous hemodynamic measurement in gastrocnemius during plantar flexion exercise

NASA Astrophysics Data System (ADS)

Henry, Brad; Zhao, Mingjun; Shang, Yu; Uhl, Timothy; Thomas, D. Travis; Xenos, Eleftherios S.; Saha, Sibu P.; Yu, Guoqiang

2015-12-01

Occlusion calibrations and gating techniques have been recently applied by our laboratory for continuous and absolute diffuse optical measurements of forearm muscle hemodynamics during handgrip exercises. The translation of these techniques from the forearm to the lower limb is the goal of this study as various diseases preferentially affect muscles in the lower extremity. This study adapted a hybrid near-infrared spectroscopy and diffuse correlation spectroscopy system with a gating algorithm to continuously quantify hemodynamic responses of medial gastrocnemius during plantar flexion exercises in 10 healthy subjects. The outcomes from optical measurement include oxy-, deoxy-, and total hemoglobin concentrations, blood oxygen saturation, and relative changes in blood flow (rBF) and oxygen consumption rate (rV˙O2). We calibrated rBF and rV˙O2 profiles with absolute baseline values of BF and V˙O2 obtained by venous and arterial occlusions, respectively. Results from this investigation were comparable to values from similar studies. Additionally, significant correlation was observed between resting local muscle BF measured by the optical technique and whole limb BF measured concurrently by a strain gauge venous plethysmography. The extensive hemodynamic and metabolic profiles during exercise will allow for future comparison studies to investigate the diagnostic value of hybrid technologies in muscles affected by disease.

Benefits of supplemental oxygen in exercise training in nonhypoxemic chronic obstructive pulmonary disease patients.

PubMed

Emtner, Margareta; Porszasz, Janos; Burns, Mary; Somfay, Attila; Casaburi, Richard

2003-11-01

Supplemental oxygen improves exercise tolerance of normoxemic and hypoxemic chronic obstructive pulmonary disease (COPD) patients. We determined whether nonhypoxemic COPD patients undergoing exercise training while breathing supplemental oxygen achieve higher intensity and therefore improve exercise capacity more than patients breathing air. A double-blinded trial was performed involving 29 nonhypoxemic patients (67 years, exercise SaO2 > 88%) with COPD (FEV1 = 36% predicted). All exercised on cycle ergometers for 45 minutes, 3 times per week for 7 weeks at high-intensity targets. During exercise, they received oxygen (3 L/minute) (n = 14) or compressed air (3 L/minute) (n = 15). Both groups had a higher exercise tolerance after training and when breathing oxygen. However, the oxygen-trained group increased the training work rate more rapidly than the air-trained group. The mean +/- SD work rate during the last week was 62 +/- 19 W (oxygen-trained group) and 52 +/- 22 W (air-trained group) (p < 0.01). After training, endurance in constant work rate tests increased more in the oxygen-trained group (14.5 minutes) than in the air-trained group (10.5 minutes) (p < 0.05). At isotime, the breathing rate decreased four breaths per minute in the oxygen-trained group and one breath per minute in the air-trained group (p = 0.001). We conclude that supplemental oxygen provided during high-intensity training yields higher training intensity and evidence of gains in exercise tolerance in laboratory testing.

Critical Power: An Important Fatigue Threshold in Exercise Physiology

PubMed Central

Poole, David C.; Burnley, Mark; Vanhatalo, Anni; Rossiter, Harry B.; Jones, Andrew M.

2016-01-01

The hyperbolic form of the power-duration relationship is rigorous and highly conserved across species, forms of exercise and individual muscles/muscle groups. For modalities such as cycling, the relationship resolves to two parameters, the asymptote for power (critical power, CP) and the so-called W′ (work doable above CP), which together predict the tolerable duration of exercise above CP. Crucially, the CP concept integrates sentinel physiological profiles - respiratory, metabolic and contractile - within a coherent framework that has great scientific and practical utility. Rather than calibrating equivalent exercise intensities relative to metabolically distant parameters such as the lactate threshold or V̇O2 max, setting the exercise intensity relative to CP unifies the profile of systemic and intramuscular responses and, if greater than CP, predicts the tolerable duration of exercise until W′ is expended, V̇O2 max is attained, and intolerance is manifested. CP may be regarded as a ‘fatigue threshold’ in the sense that it separates exercise intensity domains within which the physiological responses to exercise can (CP) be stabilized. The CP concept therefore enables important insights into 1) the principal loci of fatigue development (central vs. peripheral) at different intensities of exercise, and 2) mechanisms of cardiovascular and metabolic control and their modulation by factors such as O2 delivery. Practically, the CP concept has great potential application in optimizing athletic training programs and performance as well as improving the life quality for individuals enduring chronic disease. PMID:27031742

Critical Power: An Important Fatigue Threshold in Exercise Physiology.

PubMed

Poole, David C; Burnley, Mark; Vanhatalo, Anni; Rossiter, Harry B; Jones, Andrew M

2016-11-01

: The hyperbolic form of the power-duration relationship is rigorous and highly conserved across species, forms of exercise, and individual muscles/muscle groups. For modalities such as cycling, the relationship resolves to two parameters, the asymptote for power (critical power [CP]) and the so-called W' (work doable above CP), which together predict the tolerable duration of exercise above CP. Crucially, the CP concept integrates sentinel physiological profiles-respiratory, metabolic, and contractile-within a coherent framework that has great scientific and practical utility. Rather than calibrating equivalent exercise intensities relative to metabolically distant parameters such as the lactate threshold or V˙O2max, setting the exercise intensity relative to CP unifies the profile of systemic and intramuscular responses and, if greater than CP, predicts the tolerable duration of exercise until W' is expended, V˙O2max is attained, and intolerance is manifested. CP may be regarded as a "fatigue threshold" in the sense that it separates exercise intensity domains within which the physiological responses to exercise can (CP) be stabilized. The CP concept therefore enables important insights into 1) the principal loci of fatigue development (central vs. peripheral) at different intensities of exercise and 2) mechanisms of cardiovascular and metabolic control and their modulation by factors such as O2 delivery. Practically, the CP concept has great potential application in optimizing athletic training programs and performance as well as improving the life quality for individuals enduring chronic disease.

Repeated high-intensity exercise modulates Ca(2+) sensitivity of human skeletal muscle fibers.

PubMed

Gejl, K D; Hvid, L G; Willis, S J; Andersson, E; Holmberg, H-C; Jensen, R; Frandsen, U; Hansen, J; Plomgaard, P; Ørtenblad, N

2016-05-01

The effects of short-term high-intensity exercise on single fiber contractile function in humans are unknown. Therefore, the purposes of this study were: (a) to access the acute effects of repeated high-intensity exercise on human single muscle fiber contractile function; and (b) to examine whether contractile function was affected by alterations in the redox balance. Eleven elite cross-country skiers performed four maximal bouts of 1300 m treadmill skiing with 45 min recovery. Contractile function of chemically skinned single fibers from triceps brachii was examined before the first and following the fourth sprint with respect to Ca(2+) sensitivity and maximal Ca(2+) -activated force. To investigate the oxidative effects of exercise on single fiber contractile function, a subset of fibers was incubated with dithiothreitol (DTT) before analysis. Ca(2+) sensitivity was enhanced by exercise in both MHC I (17%, P < 0.05) and MHC II (15%, P < 0.05) fibers. This potentiation was not present after incubation of fibers with DTT. Specific force of both MHC I and MHC II fibers was unaffected by exercise. In conclusion, repeated high-intensity exercise increased Ca(2+) sensitivity in both MHC I and MHC II fibers. This effect was not observed in a reducing environment indicative of an exercise-induced oxidation of the human contractile apparatus. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Can HRV be used to evaluate training load in constant load exercises?

PubMed

Kaikkonen, Piia; Hynynen, Esa; Mann, Theresa; Rusko, Heikki; Nummela, Ari

2010-02-01

The overload principle of training states that training load (TL) must be sufficient to threaten the homeostasis of cells, tissues, organs, and/or body. However, there is no "golden standard" for TL measurement. The aim of this study was to examine if any post-exercise heart rate variability (HRV) indices could be used to evaluate TL in exercises with different intensities and durations. Thirteen endurance-trained males (35 +/- 5 year) performed MODE (moderate intensity, 3 km at 60% of the maximal velocity of the graded maximal test (vVO(2max))), HI (high intensity, 3 km at 85% vVO(2max)), and PRO (prolonged, 14 km at 60% vVO(2max)) exercises on a treadmill. HRV was analyzed with short-time Fourier-transform method during rest, exercise, and 15-min recovery. Rating of perceived exertion (RPE), blood lactate (BLa), and HFP(120) (mean of 0-120 s post-exercise) described TL of these exercises similarly, being different for HI (P < 0.05) and PRO (P < 0.05) when compared with MODE. RPE and BLa also correlated negatively with HFP(120) (r = -0.604, -0.401), LFP(120) (-0.634, -0.601), and TP(120) (-0.691, -0.569). HRV recovery dynamics were similar after each exercise, but the level of HRV was lower after HI than MODE. Increased intensity or duration of exercise decreased immediate HRV recovery, suggesting that post-exercise HRV may enable an objective evaluation of TL in field conditions. The first 2-min recovery seems to give enough information on HRV recovery for evaluating TL.

Are the oxygen uptake and heart rate off-kinetics influenced by the intensity of prior exercise?

PubMed

do Nascimento Salvador, Paulo Cesar; de Aguiar, Rafael Alves; Teixeira, Anderson Santiago; Souza, Kristopher Mendes de; de Lucas, Ricardo Dantas; Denadai, Benedito Sérgio; Guglielmo, Luiz Guilherme Antonacci

2016-08-01

The aim of this study was to investigate the effect of prior exercise on the heart rate (HR) and oxygen uptake (VO2) off-kinetics after a subsequent high-intensity running exercise. Thirteen male futsal players (age 22.8±6.1years) performed a series of high-intensity bouts without prior exercise (control), preceded by a prior same intensity continuous exercise (CE+CE) and a prior sprint exercise (SE+CE). The magnitude of excess post-exercise oxygen consumption (EPOCm-4.25±0.19 vs. 3.69±0.20Lmin(-1) in CE+CE and 3.62±0.18Lmin(-1) in control; p<0.05) and the parasympathetic reactivation (HRR60s-33±3 vs. 37±3bpm in CE+CE and 42±3 bpm in control; p<0.05) in the SE+CE were higher and slower, compared with another two conditions. The EPOCτ (time to attain 63% of total response; 53±2s) and the heart rate time-course (HRτ-86±5s) were significantly longer after the SE+CE condition than control transition (48±2s and 69±5s, respectively; p<0.05). The SE+CE induce greater stress on the metabolic function, respiratory system and autonomic nervous system regulation during post-exercise recovery than CE, highlighting that the inclusion of sprint-based exercises can be an effective strategy to increase the total energy expenditure following an exercise session. Copyright © 2016 Elsevier B.V. All rights reserved.

New perspectives concerning feedback influences on cardiorespiratory control during rhythmic exercise and on exercise performance

PubMed Central

Dempsey, Jerome A

2012-01-01

The cardioaccelerator and ventilatory responses to rhythmic exercise in the human are commonly viewed as being mediated predominantly via feedforward ‘central command’ mechanisms, with contributions from locomotor muscle afferents to the sympathetically mediated pressor response. We have assessed the relative contributions of three types of feedback afferents on the cardiorespiratory response to voluntary, rhythmic exercise by inhibiting their normal ‘tonic’ activity in healthy animals and humans and in chronic heart failure. Transient inhibition of the carotid chemoreceptors during moderate intensity exercise reduced muscle sympathetic nerve activity (MSNA) and increased limb vascular conductance and blood flow; and reducing the normal level of respiratory muscle work during heavier intensity exercise increased limb vascular conductance and blood flow. These cardiorespiratory effects were prevented via ganglionic blockade and were enhanced in chronic heart failure and in hypoxia. Blockade of μ opioid sensitive locomotor muscle afferents, with preservation of central motor output via intrathecal fentanyl: (a) reduced the mean arterial blood pressure (MAP), heart rate and ventilatory responses to all steady state exercise intensities; and (b) during sustained high intensity exercise, reduced O2 transport, increased central motor output and end-exercise muscle fatigue and reduced endurance performance. We propose that these three afferent reflexes – probably acting in concert with feedforward central command – contribute significantly to preserving O2 transport to locomotor and to respiratory muscles during exercise. Locomotor muscle afferents also appear to provide feedback concerning the metabolic state of the muscle to influence central motor output, thereby limiting peripheral fatigue development. PMID:22826128

High- and moderate-intensity aerobic exercise and excess post-exercise oxygen consumption in men with metabolic syndrome.

PubMed

Larsen, I; Welde, B; Martins, C; Tjønna, A E

2014-06-01

Physical activity is central in prevention and treatment of metabolic syndrome. High-intensity aerobic exercise can induce larger energy expenditure per unit of time compared with moderate-intensity exercise. Furthermore, it may induce larger energy expenditure at post-exercise recovery. The aim of this study is to compare the excess post-exercise oxygen consumption (EPOC) in three different aerobic exercise sessions in men with metabolic syndrome. Seven men (age: 56.7 ± 10.8) with metabolic syndrome participated in this crossover study. The sessions consisted of one aerobic interval (1-AIT), four aerobic intervals (4-AIT), and 47-min continuous moderate exercise (CME) on separate days, with at least 48 h between each test day. Resting metabolic rate (RMR) was measured pre-exercise and used as baseline value. EPOC was measured until baseline metabolic rate was re-established. An increase in O2 uptake lasting for 70.4 ± 24.8 min (4-AIT), 35.9 ± 17.3 min (1-AIT), and 45.6 ± 17.3 min (CME) was observed. EPOC were 2.9 ± 1.7 L O2 (4-AIT), 1.3 ±  .1 L O2 (1-AIT), and 1.4 ± 1.1 L O2 (CME). There were significant differences (P < 0.001) between 4-AIT, CME, and 1-AIT. Total EPOC was highest after 4-AIT. These data suggest that exercise intensity has a significant positive effect on EPOC in men with metabolic syndrome. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Appetite and gut hormone responses to moderate-intensity continuous exercise versus high-intensity interval exercise, in normoxic and hypoxic conditions.

PubMed

Bailey, Daniel P; Smith, Lindsey R; Chrismas, Bryna C; Taylor, Lee; Stensel, David J; Deighton, Kevin; Douglas, Jessica A; Kerr, Catherine J

2015-06-01

This study investigated the effects of continuous moderate-intensity exercise (MIE) and high-intensity interval exercise (HIIE) in combination with short exposure to hypoxia on appetite and plasma concentrations of acylated ghrelin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). Twelve healthy males completed four, 2.6 h trials in a random order: (1) MIE-normoxia, (2) MIE-hypoxia, (3) HIIE-normoxia, and (4) HIIE-hypoxia. Exercise took place in an environmental chamber. During MIE, participants ran for 50 min at 70% of altitude-specific maximal oxygen uptake (V˙O2max) and during HIIE performed 6 × 3 min running at 90% V˙O2max interspersed with 6 × 3 min active recovery at 50% V˙O2max with a 7 min warm-up and cool-down at 70% V˙O2max (50 min total). In hypoxic trials, exercise was performed at a simulated altitude of 2980 m (14.5% O2). Exercise was completed after a standardised breakfast. A second meal standardised to 30% of participants' daily energy requirements was provided 45 min after exercise. Appetite was suppressed more in hypoxia than normoxia during exercise, post-exercise, and for the full 2.6 h trial period (linear mixed modelling, p <0.05). Plasma acylated ghrelin concentrations were lower in hypoxia than normoxia post-exercise and for the full 2.6 h trial period (p <0.05). PYY concentrations were higher in HIIE than MIE under hypoxic conditions during exercise (p = 0.042). No differences in GLP-1 were observed between conditions (p > 0.05). These findings demonstrate that short exposure to hypoxia causes suppressions in appetite and plasma acylated ghrelin concentrations. Furthermore, appetite responses to exercise do not appear to be influenced by exercise modality. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sprint-based exercise and cognitive function in adolescents.

PubMed

Cooper, Simon B; Bandelow, Stephan; Nute, Maria L; Dring, Karah J; Stannard, Rebecca L; Morris, John G; Nevill, Mary E

2016-12-01

Moderate intensity exercise has been shown to enhance cognition in an adolescent population, yet the effect of high-intensity sprint-based exercise remains unknown and was therefore examined in the present study. Following ethical approval and familiarisation, 44 adolescents (12.6 ± 0.6 y) completed an exercise (E) and resting (R) trial in a counter-balanced, randomised crossover design. The exercise trial comprised of 10 × 10 s running sprints, interspersed by 50 s active recovery (walking). A battery of cognitive function tests (Stroop, Digit Symbol Substitution (DSST) and Corsi blocks tests) were completed 30 min pre-exercise, immediately post-exercise and 45 min post-exercise. Data were analysed using mixed effect models with repeated measures. Response times on the simple level of the Stroop test were significantly quicker 45 min following sprint-based exercise (R: 818 ± 33 ms, E: 772 ± 26 ms; p = 0.027) and response times on the complex level of the Stroop test were quicker immediately following the sprint-based exercise (R: 1095 ± 36 ms, E: 1043 ± 37 ms; p = 0.038), while accuracy was maintained. Sprint-based exercise had no immediate or delayed effects on the number of items recalled on the Corsi blocks test (p = 0.289) or substitutions made during the DSST (p = 0.689). The effect of high intensity sprint-based exercise on adolescents' cognitive function was dependant on the component of cognitive function examined. Executive function was enhanced following exercise, demonstrated by improved response times on the Stroop test, whilst visuo-spatial memory and general psycho-motor speed were unaffected. These data support the inclusion of high-intensity sprint-based exercise for adolescents during the school day to enhance cognition.

Anxiety sensitivity as a mediator of the relationship between moderate-intensity exercise and coping-oriented marijuana use motives.

PubMed

Smits, Jasper A J; Bonn-Miller, Marcel O; Tart, Candyce D; Irons, Jessica G; Zvolensky, Michael J

2011-01-01

The present study examined the working hypothesis that moderate-intensity exercise is associated with coping-oriented marijuana use motives through its association with the fear of somatic arousal (ie, anxiety sensitivity). Using data from 146 young adult current marijuana users, we found evidence consistent with this hypothesis. Specifically, moderate-intensity exercise was associated with coping-oriented use motives, even after controlling for frequency of current marijuana use and other co-occurring marijuana use motives. This relationship became nonsignificant after entering anxiety sensitivity as an additional predictor variable, denoting a putative mediational role for this cognitive factor. These findings extend previous work and offer support for the potential utility of moderate-intensity aerobic exercise for the treatment of marijuana use problems. © American Academy of Addiction Psychiatry.

Analysis of muscle activation in each body segment in response to the stimulation intensity of whole-body vibration.

PubMed

Lee, Dae-Yeon

2017-02-01

[Purpose] The purpose of this study was to investigate the effects of a whole-body vibration exercise, as well as to discuss the scientific basis to establish optimal intensity by analyzing differences between muscle activations in each body part, according to the stimulation intensity of the whole-body vibration. [Subjects and Methods ] The study subjects included 10 healthy men in their 20s without orthopedic disease. Representative muscles from the subjects' primary body segments were selected while the subjects were in upright positions on exercise machines; electromyography electrodes were attached to the selected muscles. Following that, the muscle activities of each part were measured at different intensities. No vibration, 50/80 in volume, and 10/25/40 Hz were mixed and applied when the subjects were on the whole-vibration exercise machines in upright positions. After that, electromyographic signals were collected and analyzed with the root mean square of muscular activation. [Results] As a result of the analysis, it was found that the muscle activation effects had statistically meaningful differences according to changes in exercise intensity in all 8 muscles. When the no-vibration status was standardized and analyzed as 1, the muscle effect became lower at higher frequencies, but became higher at larger volumes. [Conclusion] In conclusion, it was shown that the whole-body vibration stimulation promoted muscle activation across the entire body part, and the exercise effects in each muscle varied depending on the exercise intensities.

The association between pregame snacks and exercise intensity, stress, and fatigue in children.

PubMed

Sacheck, Jennifer M; Rasmussen, Helen M; Hall, Meghan M; Kafka, Tamar; Blumberg, Jeffrey B; Economos, Christina D

2014-05-01

To investigate the association between pregame snacks varying in macronutrient content and exercise intensity, physiological stress, and fatigue in young soccer players. One hour before a 50-min soccer game, children (n = 79; 9.1 ± 0.8 y) were randomly assigned to consume a raisin-, peanut-butter-, or cereal-based snack. Body mass index, blood glucose, and salivary measures of stress (cortisol and immunoglobulin A-IgA) were measured pre- and post-game. Exercise intensity was measured by accelerometry. Self-administered questionnaires were used to assess diet quality and fatigue. Analysis of covariance was used to examine the relationship between pregame snacks and biochemical outcomes. Postgame glucose and cortisol increased [12.9 ± 21.3 mg/dL (p < .001) and 0.04 ± 0.10 μg/dL (p < .05), respectively] and IgA decreased (-2.3 ± 9.6 μg/mL; p < .001) from pregame values. The pregame snack was not associated with exercise intensity or post-game outcome; however, children consuming the cereal-based (high-sugar and high-glycemic index (GI)) snack exercised more intensely than the 2 lower-GI snack groups (p < .05). Children who consumed the high-sugar, high-GI snack also reported more symptoms of fatigue (p < .05). A high-sugar, high-GI pregame snack was associated with exercise intensity and fatigue but not changes in blood sugar or stress biomarkers following a soccer game in children.

Intermittent, moderate-intensity aerobic exercise for only eight weeks reduces arterial stiffness: evaluation by measurement of stiffness parameter and pressure-strain elastic modulus by use of ultrasonic echo tracking.

PubMed

Tanaka, Midori; Sugawara, Motoaki; Ogasawara, Yasuo; Izumi, Tadafumi; Niki, Kiyomi; Kajiya, Fumihiko

2013-04-01

Aerobic exercise has been reported to be associated with reduced arterial stiffness. However, the intensity, duration, and frequency of aerobic exercise required to improve arterial stiffness have not been established. In addition, most reports base their conclusions on changes in pulse wave velocity, which is an indirect index of arterial stiffness. We studied the effects of short-term, intermittent, moderate-intensity exercise training on arterial stiffness based on measurements of the stiffness parameter (β) and pressure-strain elastic modulus (E p), which are direct indices of regional arterial stiffness. A total of 25 young healthy volunteers (18 men) were recruited. By use of ultrasonic diagnostic equipment we measured β and E p of the carotid artery before and after 8 weeks of exercise training. After exercise training, systolic pressure (P s), diastolic pressure (P d), pulse pressure, systolic arterial diameter (D s), and diastolic arterial diameter (D d) did not change significantly. However, the pulsatile change in diameter ((D s - D d)/D d) increased significantly, and β and E p decreased significantly. For healthy young subjects, β and E p were reduced by intermittent, moderate-intensity exercise training for only 8 weeks.

Physical dose of therapeutic exercises in institutional neck rehabilitation.

PubMed

Wasenius, Niko; Karapalo, Teppo; Sjögren, Tuulikki; Pekkonen, Mika; Mälkiä, Esko

2013-03-01

To determine the intensity and volume of therapeutic exercises during a standard 13-day inpatient neck rehabilitation course in relation to overall physical activity in rehabilitation and everyday life. Cross-sectional study. Subjects (n = 19; 16 women and 3 men; mean age 48.6 years, standard deviation (SD) 6.6) with chronic non-specific neck pain were recruited from two inpatient neck rehabilitation courses. Intensity and volume of therapeutic exercises and physical activity were measured in metabolic equivalents (METs) with an objective measurement device and all-time recall questionnaire. Maximum oxygen uptake was determined in METs (METc) by direct maximal cycle ergometer. Subjects' mean METc was 7.2 METs (SD 1.4) or 25.3 ml/kg/min (SD 4.8). Intensity of all therapeutic exercises was 1.9 METs or 27 %METc (SD 5.1) and volume 7.7 MET-hours/week. Intensity of specific neck and shoulder exercises was 2.0 METs or 28 %METc (SD 5.4) and volume 2.5 MET-hours/week. In addition, subjects were more active in everyday life than in inpatient rehabilitation. The therapeutic exercise dose failed to reach previously reported target values for pain relief. The dose of therapeutic exercises and confounding physical activity should be carefully controlled in pain rehabilitation programmes.

Dynamic characteristics of T2*-weighted signal in calf muscles of peripheral artery disease during low-intensity exercise.

PubMed

Li, Zhijun; Muller, Matthew D; Wang, Jianli; Sica, Christopher T; Karunanayaka, Prasanna; Sinoway, Lawrence I; Yang, Qing X

2017-07-01

To evaluate the dynamic characteristics of T2* -weighted signal change in exercising skeletal muscle of healthy subjects and peripheral artery disease (PAD) patients under a low-intensity exercise paradigm. Nine PAD patients and nine age- and sex-matched healthy volunteers underwent a low-intensity exercise paradigm while magnetic resonance imaging (MRI) (3.0T) was obtained. T2*-weighted signal time-courses in lateral gastrocnemius, medial gastrocnemius, soleus, and tibialis anterior were acquired and analyzed. Correlations were performed between dynamic T2*-weighted signal and changes in heart rate, mean arterial pressure, leg pain, and perceived exertion. A significant signal decrease was observed during exercise in soleus and tibialis anterior of healthy participants (P = 0.0007-0.04 and 0.001-0.009, respectively). In PAD, negative signals were observed (P = 0.008-0.02 and 0.003-0.01, respectively) in soleus and lateral gastrocnemius during the early exercise stage. Then the signal gradually increased above the baseline in the lateral gastrocnemius during and after exercise in six of the eight patients who completed the study. This signal increase in patients' lateral gastrocnemius was significantly greater than in healthy subjects' during the later exercise stage (two-sample t-tests, P = 0.001-0.03). Heart rate and mean arterial pressure responses to exercise were significantly higher in PAD than healthy subjects (P = 0.036 and 0.008, respectively) and the patients experienced greater leg pain and exertion (P = 0.006 and P = 0.0014, respectively). During low-intensity exercise, there were different dynamic T2*-weighted signal behavior in the healthy and PAD exercising muscles. 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:40-48. © 2016 International Society for Magnetic Resonance in Medicine.

Active play exercise intervention in children with asthma: a PILOT STUDY

PubMed Central

Westergren, Thomas; Fegran, Liv; Nilsen, Tonje; Haraldstad, Kristin; Kittang, Ole Bjørn; Berntsen, Sveinung

2016-01-01

Objective Increased physical activity (PA) may be beneficial for children with asthma. Knowledge about how to intervene and encourage children with asthma to be physically active is required. In the present study, we aimed to pilot a 6-week exercise intervention designed as active play and examine attendance rate, exercise intensity and children's perceptions of participating. Methods 6 children with asthma (4 boys, 2 girls) aged 10–12 years, participated in 60 min of active play exercise twice weekly. A mixed-methods design was applied. The data analysed included attendance rate, exercise intensity assessed by heart rate (HR) monitoring during exercise sessions, registration and description of the active play exercise programme, 3 semistructured focus groups, field observations of 5 exercise sessions, and preintervention and postintervention testing. Findings The average attendance rate was 90%. Intensity ≥80% of maximal HR (HRmax) was recorded for a median (IQR) time of 22 (8) out of 60 min per session. Median (IQR) HR during the sessions was 146 (9; 74% of HRmax) bpm. Children reported increased health-related quality of life (HRQoL) post-test compared with baseline. Children enjoyed participating and reported no limitations by asthma or serious asthma attacks. Instead, they perceived that their asthma and fitness had improved after the programme. The instructors created an inclusive atmosphere that was characterised by easy-to-master games, fair competition, humour and mutual participation. Conclusions The exercise intervention pilot focusing on active play had a high attendance rate, relatively high exercise intensity, and satisfaction; the children perceived that their fitness and asthma had improved, and reported increased HRQoL. A randomised controlled trial of active play exercise including children with asthma should be conducted to evaluate effect on PA level, physical fitness, asthma control and HRQoL. PMID:26733570

Long-lasting effects of fluoxetine and/or exercise augmentation on bio-behavioural markers of depression in pre-pubertal stress sensitive rats.

PubMed

Schoeman, Jacobus C; Steyn, Stephanus F; Harvey, Brian H; Brink, Christiaan B

2017-04-14

Juvenile depression is of great concern with only limited treatment currently approved. Delayed onset of action, low remission and high relapse rates, and potential long-lasting consequences further complicates treatment and highlights the need for new treatment options. Studies reporting on long-lasting effects of early-life treatment have reported conflicting results, with the pre-adolescent period mostly overlooked. The anti-depressive effect of exercise, as a possible treatment option or augmentation strategy, is dependent on age and exercise intensity. We investigated the immediate (i.e. postnatal day 35 (PND35)) and lasting (PND60 to PND61) effects of pre-pubertal (PND21 to PND34) fluoxetine and/or exercise on bio-behavioural markers of depression and oxidative stress in stress sensitive Flinders Sensitive Line rats. Low, but not moderate, intensity exercise or 5, but not 10, mg/kg/day fluoxetine displayed anti-depressant-like properties at PND35. Pre-pubertal treatment with 5mg/kg/day fluoxetine or low intensity exercise exerted lasting anti-depressive-like effects into adulthood, whereas the combination of these two treatments did not. Furthermore, the combination of fluoxetine plus exercise reduced hippocampal BDNF levels as compared to exercise alone, which may explain the latter findings. In all treatment groups hippocampal SOD activity was significantly increased at PND61, suggesting an increased anti-oxidant capacity in adulthood. In conclusion, the data confirm the anti-depressant-like properties of both early-life fluoxetine and exercise in a genetic animal model of depression. However, optimal lasting effects of early-life interventions may require adjustment of antidepressant dose and/or exercise intensity to developmental age, and that a combination of antidepressant and exercise may not necessarily be augmentative. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of low and moderate intensity aerobic exercises on sleep quality in men older adults.

PubMed

Akbari Kamrani, Ahmad Ali; Shams, Amir; Shamsipour Dehkordi, Parvaneh; Mohajeri, Robabeh

2014-03-01

Sleep is an active and complex rhythmic state that may be affected by the aging process. The purpose of present research was to investigate the effect of low and moderate intensity aerobic exercises on sleep quality in older adults. The research method is quasi-experimental with pre-test and post-test design. The statistical sample included 45 volunteer elderly men with age range of 60-70 years-old that divided randomly in two experimental groups (aerobic exercise with low and moderate intensity) and one control group. In each group selected 15 older adults based on inclusion and exclusion criteria (such as, without sleep apnea, not smoking, and no taking hypnotic drugs). First, all subjects were evaluated by a doctor to confirm their physical and mental health. Also, the maximum heart rate (MaxHR) of subjects was obtained by subtracting one's age from 220. Furthermore, based on aerobic exercise type (40-50% MaxHR for low intensity group and 60-70% MaxHR for moderate intensity group) the target MaxHR was calculated for each subject. The exercise protocol consisted of 8 weeks aerobic exercises (2 sessions in per-week) based on Rockport one-mile walking/running test and the control group continued their daily activities. All subjects in per-test and post-test stages completed the Petersburg Sleep Quality Index (PSQI). In pre-test stage, results showed that there were no significant differences between control and experimental groups in sleep quality and its components (P>0.05). On the other hand, results in post-test stage showed that there were significant differences between control and experimental groups in these variables (P<0.05). Also, the Tukey Post Hoc showed that the moderate intensity group scores in total sleep quality and its components were better than other groups (P<0.05). Finally, the low intensity group scores in total sleep quality and its components were better than control group (P<0.05). Generally, the present research showed that the aerobic exercises with moderate intensity (60-70% MaxHR) have a positive and significant effect on sleep quality and its components. Thus, based on these findings, the aerobic exercises with moderate intensity is a useful to improve the sleep quality and its components among community older adults were recommended.

[Cardiovascular clearance for competitive sport in aging people].

PubMed

Carré, François

2013-06-01

The regular sport practice slows the physiological deleterious effects of aging. However, during intense exercise, the hazard of acute cardiovascular event is significantly increased. Whatever their cardiovascular risk factors are, aging people are more prone to coronary acute event during intense exertion than a young one. Cardiovascular exam, with resting ECG and maximal exercise test, is needed to give clearance for competitive sport in aging people (>65 y.o.). The limited value to evaluate the individual risk of acute cardiac event during intense exercise must be clearly explained to Master athletes. They must be aware to the necessity to consult their physician in case of abnormal symptom during exercise. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Simulated Partners and Collaborative Exercise (SPACE) to boost motivation for astronauts: study protocol.

PubMed

Feltz, Deborah L; Ploutz-Snyder, Lori; Winn, Brian; Kerr, Norbert L; Pivarnik, James M; Ede, Alison; Hill, Christopher; Samendinger, Stephen; Jeffery, William

2016-11-14

Astronauts may have difficulty adhering to exercise regimens at vigorous intensity levels during long space missions. Vigorous exercise is important for aerobic and musculoskeletal health during space missions and afterwards. A key impediment to maintaining vigorous exercise is motivation. Finding ways to motivate astronauts to exercise at levels necessary to mitigate reductions in musculoskeletal health and aerobic capacity have not been explored. The focus of Simulated Partners and Collaborative Exercise (SPACE) is to use recently documented motivation gains in task groups to heighten the exercise experience for participants, similar in age and fitness to astronauts, for vigorous exercise over a 6-month exercise regimen. A secondary focus is to determine the most effective features in simulated exercise partners for enhancing enjoyment, self-efficacy, and social connectedness. The aims of the project are to (1) Create software-generated (SG) exercise partners and interface software with a cycle ergometer; (2) Pilot test design features of SG partners within a video exercise game (exergame), and (3) Test whether exercising with an SG partner over 24-week time period, compared to exercising alone, leads to greater work effort, aerobic capacity, muscle strength, exercise adherence, and enhanced psychological parameters. This study was approved by the Institutional Review Board (IRB). Chronic exercisers, between the ages 30 and 62, were asked to exercise on a cycle ergometer 6 days per week for 24 weeks using a routine consisting of alternating between moderate-intensity continuous and high-intensity interval sessions. Participants were assigned to one of three conditions: no partner (control), always faster SG partner, or SG partner who was not always faster. Participants were told they could vary cycle ergometer output to increase or decrease intensity during the sessions. Mean change in cycle ergometer power (watts) from the initial continuous and 4 min. interval sessions was the primary dependent variable reflecting work effort. Measures of physiological, strength, and psychological parameters were also taken. This paper describes the rationale, development, and methods of the SPACE exergame. We believe this will be a viable intervention that can be disseminated for astronaut use and adapted for use by other populations.

A pilot study on quantification of training load: The use of HRV in training practice.

PubMed

Saboul, Damien; Balducci, Pascal; Millet, Grégoire; Pialoux, Vincent; Hautier, Christophe

2016-01-01

Recent laboratory studies have suggested that heart rate variability (HRV) may be an appropriate criterion for training load (TL) quantification. The aim of this study was to validate a novel HRV index that may be used to assess TL in field conditions. Eleven well-trained long-distance male runners performed four exercises of different duration and intensity. TL was evaluated using Foster and Banister methods. In addition, HRV measurements were performed 5 minutes before exercise and 5 and 30 minutes after exercise. We calculated HRV index (TLHRV) based on the ratio between HRV decrease during exercise and HRV increase during recovery. HRV decrease during exercise was strongly correlated with exercise intensity (R = -0.70; p < 0.01) but not with exercise duration or training volume. TLHRV index was correlated with Foster (R = 0.61; p = 0.01) and Banister (R = 0.57; p = 0.01) methods. This study confirms that HRV changes during exercise and recovery phase are affected by both intensity and physiological impact of the exercise. Since the TLHRV formula takes into account the disturbance and the return to homeostatic balance induced by exercise, this new method provides an objective and rational TL index. However, some simplification of the protocol measurement could be envisaged for field use.

Validation of a personal fluid loss monitor.

PubMed

Wickwire, J; Bishop, P A; Green, J M; Richardson, M T; Lomax, R G; Casaru, C; Jones, E; Curtner-Smith, M

2008-02-01

Dehydration raises heat injury risk and reduces performance [ , , ]. The purpose was to validate the Hydra-Alert Jr (Acumen). The Hydra-Alert was tested in two exercise/clothing conditions. Participants wore it while wearing exercise clothing and exercising at a self-selected intensity (n = 8). Others wore the Hydra-Alert while wearing a ballistic-vest and performing an industrial-protocol (n = 8). For each condition, the Hydra-Alert was tested on two occasions (T1 and T2). The Hydra-Alert was tested against nude weight loss for both conditions. The Hydra-Alert had low test-retest reliability for both conditions (average absolute value of the error between Hydra-Alert outputs of T1 and T2 = 0.08 +/- 0.08 percentage points). With exercise-clothing, the Hydra-Alert evidenced low-moderate correlations between percent nude weight loss and Hydra-Alert output at 20 min (r = 0.59-T1, p = 0.13; r = 0.12-T2, p = 0.78), at 40 min (r = 0.93-T1, p = 0.001; r = 0.63-T2, p = 0.10), and at approximately 2 % weight loss (r = 0.21-T1 and T2, p = 0.61 and 0.62, respectively). The correlation at 40 min during T1 fell during T2 suggesting the Hydra-Alert was inconsistent. When wearing a ballistic-vest, the Hydra-Alert had poor validity (T1: r = - 0.29 [p = 0.48] for weight loss vs. monitor; T2: r = 0.11 [p = 0.80]). At the higher levels of dehydration ( approximately 2 %), the Hydra-Alert error was so high as to render its readings of little value. In some cases, the Hydra-Alert could lead to a false level of security if dehydrated. Therefore, the Hydra-Alert is of little use for those who want to measure their fluid loss while exercising in the heat.

[Effects of exercise therapy at the intensity of anaerobic threshold for exercise tolerance in patients with chronic stable coronary artery disease].

PubMed

Che, Lin; Gong, Zhu; Jiang, Jin-fa; Xu, Wen-jun; Deng, Bing; Xu, Jia-hong; Yan, Wen-wen; Zhang, Qi-ping; Wang, Le-min

2011-06-28

To investigate the effects of exercise therapy at the intensity of anaerobic threshold (AT) for exercise tolerance in patients with chronic stable coronary artery disease. Forty-three patients with chronic stable coronary artery disease (3 patients after coronary arterial bypass graft (CABG) surgery, 22 patients with old myocardial infarction and 18 unstable angina pectoris undergoing successful percutaneous coronary intervention (PCI) finished twice cardiopulmonary exercise test (CPET) and followed their rehabilitation program for 3 months. Thirty-two patients finished their aerobic exercise therapy based on their individual anaerobic thresholds while 11 patients had no exercise therapy. The heart rate at AT intensity (97 ± 9/min) was lower than their traditional minimal target heart rate (112 ± 7/min) and lower than heart rate (115 ± 11/min) at ischemic threshold post-CPET. The O(2) consumption (10.7 ± 2.4 to 12.6 ± 2.9 ml×min(-1)×kg(-1)) (P = 0.04) and workload (37 ± 18 to 47 ± 13 J/s) (P = 0.04) at AT level and the O(2) consumption (15.3 ± 3.1 to 20.6 ± 4.2 ml×min(-1)×kg(-1), P = 0.02) and workload(68 ± 12 and 87 ± 14 J/s, P = 0.01) at peak level markedly increased after 3 months in the exercise group. And the O(2) consumption (15.3 ± 2.9 to 16.2 ± 3.1 ml×min(-1)×kg(-1)) and workload (65 ± 13 to 73 ± 16 J/s) at peak level mild increased after 3 months in the non-exercise group, but their O(2) consumption (11.0 ± 2.7 to 11.3 ± 2.8 ml×min(-1)×kg(-1)) and workload (38 ± 11 to 37 ± 9 J/s) at AT level had no obvious change. AT exercise intensity was lower than ischemic threshold post-CPET. Exercise therapy at the intensity of anaerobic threshold can improve oxygen capacity and exercise tolerance.

Absolute intensity of radiation emitted by uranium plasmas

NASA Technical Reports Server (NTRS)

Jalufka, N. W.; Lee, J. H.; Mcfarland, D. R.

1975-01-01

The absolute intensity of radiation emitted by fissioning and nonfissioning uranium plasmas in the spectral range from 350 nm to 1000 nm was measured. The plasma was produced in a plasma-focus apparatus and the plasma properties are simular to those anticipated for plasma-core nuclear reactors. The results are expected to contribute to the establishment of design criteria for the development of plasma-core reactors.

The impact of brief high-intensity exercise on blood glucose levels.

PubMed

Adams, O Peter

2013-01-01

Moderate-intensity exercise improves blood glucose (BG), but most people fail to achieve the required exercise volume. High-intensity exercise (HIE) protocols vary. Maximal cycle ergometer sprint interval training typically requires only 2.5 minutes of HIE and a total training time commitment (including rest and warm up) of 25 minutes per session. The effect of brief high-intensity exercise on blood glucose levels of people with and without diabetes is reviewed. HIE (≥80% maximal oxygen uptake, VO2max) studies with ≤15 minutes HIE per session were reviewed. Six studies of nondiabetics (51 males, 14 females) requiring 7.5 to 20 minutes/week of HIE are reviewed. Two weeks of sprint interval training increased insulin sensitivity up to 3 days postintervention. Twelve weeks near maximal interval running (total exercise time 40 minutes/week) improved BG to a similar extent as running at 65% VO2max for 150 minutes/week. Eight studies of diabetics (41 type 1 and 22 type 2 subjects) were reviewed. Six were of a single exercise session with 44 seconds to 13 minutes of HIE, and the others were 2 and 7 weeks duration with 20 and 2 minutes/week HIE, respectively. With type 1 and 2 diabetes, BG was generally higher during and up to 2 hours after HIE compared to controls. With type 1 diabetics, BG decreased from midnight to 6 AM following HIE the previous morning. With type 2 diabetes, a single session improved postprandial BG for 24 hours, while a 2-week program reduced the average BG by 13% at 48 to 72 hours after exercise and also increased GLUT4 by 369%. Very brief HIE improves BG 1 to 3 days postexercise in both diabetics and non-diabetics. HIE is unlikely to cause hypoglycemia during and immediately after exercise. Larger and longer randomized studies are needed to determine the safety, acceptability, long-term efficacy, and optimal exercise intensity and duration.

Long-term lifestyle intervention with optimized high-intensity interval training improves body composition, cardiometabolic risk, and exercise parameters in patients with abdominal obesity.

PubMed

Gremeaux, Vincent; Drigny, Joffrey; Nigam, Anil; Juneau, Martin; Guilbeault, Valérie; Latour, Elise; Gayda, Mathieu

2012-11-01

The aim of this study was to study the impact of a combined long-term lifestyle and high-intensity interval training intervention on body composition, cardiometabolic risk, and exercise tolerance in overweight and obese subjects. Sixty-two overweight and obese subjects (53.3 ± 9.7 yrs; mean body mass index, 35.8 ± 5 kg/m(2)) were retrospectively identified at their entry into a 9-mo program consisting of individualized nutritional counselling, optimized high-intensity interval exercise, and resistance training two to three times a week. Anthropometric measurements, cardiometabolic risk factors, and exercise tolerance were measured at baseline and program completion. Adherence rate was 97%, and no adverse events occurred with high-intensity interval exercise training. Exercise training was associated with a weekly energy expenditure of 1582 ± 284 kcal. Clinically and statistically significant improvements were observed for body mass (-5.3 ± 5.2 kg), body mass index (-1.9 ± 1.9 kg/m(2)), waist circumference (-5.8 ± 5.4 cm), and maximal exercise capacity (+1.26 ± 0.84 metabolic equivalents) (P < 0.0001 for all parameters). Total fat mass and trunk fat mass, lipid profile, and triglyceride/high-density lipoprotein ratio were also significantly improved (P < 0.0001). At program completion, the prevalence of metabolic syndrome was reduced by 32.5% (P < 0.05). Independent predictors of being a responder to body mass and waist circumference loss were baseline body mass index and resting metabolic rate; those for body mass index decrease were baseline waist circumference and triglyceride/high-density lipoprotein cholesterol ratio. A long-term lifestyle intervention with optimized high-intensity interval exercise improves body composition, cardiometabolic risk, and exercise tolerance in obese subjects. This intervention seems safe, efficient, and well tolerated and could improve adherence to exercise training in this population.

Effect of moderate- and high-intensity acute exercise on appetite in obese individuals.

PubMed

Martins, Catia; Stensvold, Dorthe; Finlayson, Graham; Holst, Jens; Wisloff, Ulrik; Kulseng, Bård; Morgan, Linda; King, Neil A

2015-01-01

The effect of acute exercise, and exercise intensity, on appetite control in obese individuals requires further study. The aim of this study was to compare the effects of acute isocaloric bouts (250 kcal) of high-intensity intermittent cycling (HIIC) and moderate-intensity continuous cycling (MICC) or short-duration HIIC (S-HIIC) (125 kcal) and a resting control condition on the appetite hormone responses, subjective feelings of appetite, energy intake (EI), and food reward in overweight/obese individuals. This study is a randomized crossover study on 12 overweight/obese volunteers. Participants were assigned to the control, MICC, HIIC, and S-HIIC conditions, 1 wk apart, in a counterbalanced order. Exercise was performed 1 h after a standard breakfast. An ad libitum test lunch was served 3 h after breakfast. Fasting/postprandial plasma samples of insulin, acylated ghrelin, polypeptide YY3-36, and glucagon-like peptide 1 and subjective feelings of appetite were measured every 30 min for 3 h. Nutrient and taste preferences were measured at the beginning and end of each condition using the Leeds Food Preference Questionnaire. Insulin levels were significantly reduced, and glucagon-like peptide 1 levels significantly increased during all exercise bouts compared with those during rest. Acylated ghrelin plasma levels were lower in the MICC and HIIC, but not in S-HIIC, compared with those in control. There were no significant differences for polypeptide YY3-36 plasma levels, hunger or fullness ratings, EI, or food reward. Our findings suggest that, in overweight/obese individuals, isocaloric bouts of moderate- or high-intensity exercise lead to a similar appetite response. This strengthens previous findings in normal-weight individuals that acute exercise, even at high intensity, does not induce any known physiological adaptation that would lead to increased EI.

Psychophysiological effects of music on acute recovery from high-intensity interval training.

PubMed

Jones, Leighton; Tiller, Nicholas B; Karageorghis, Costas I

2017-03-01

Numerous studies have examined the multifarious effects of music applied during exercise but few have assessed the efficacy of music as an aid to recovery. Music might facilitate physiological recovery via the entrainment of respiratory rhythms with music tempo. High-intensity exercise training is not typically associated with positive affective responses, and thus ways of assuaging negative affect warrant further exploration. This study assessed the psychophysiological effects of music on acute recovery and prevalence of entrainment in between bouts of high-intensity exercise. Thirteen male runners (M age =20.2±1.9years; BMI=21.7±1.7; V̇O 2 max=61.6±6.1mL·kg·min -1 ) completed three exercise sessions comprising 5×5-min bouts of high-intensity intervals interspersed with 3-min periods of passive recovery. During recovery, participants were administered positively-valenced music of a slow-tempo (55-65bpm), fast-tempo (125-135bpm), or a no-music control. A range of measures including affective responses, RPE, cardiorespiratory indices (gas exchange and pulmonary ventilation), and music tempo-respiratory entrainment were recorded during exercise and recovery. Fast-tempo, positively-valenced music resulted in higher Feeling Scale scores throughout recovery periods (p<0.01, η p 2 =0.38). There were significant differences in HR during initial recovery periods (p<0.05, η p 2 =0.16), but no other music-moderated differences in cardiorespiratory responses. In conclusion, fast-tempo, positively-valenced music applied during recovery periods engenders a more pleasant experience. However, there is limited evidence that music expedites cardiorespiratory recovery in between bouts of high-intensity exercise. These findings have implications for athletic training strategies and individuals seeking to make high-intensity exercise sessions more pleasant. Copyright © 2016 Elsevier Inc. All rights reserved.

The effect of low and high-intensity cycling in diesel exhaust on flow-mediated dilation, circulating NOx, endothelin-1 and blood pressure

PubMed Central

Tebbutt, Scott J.; Carlsten, Christopher; Koehle, Michael S.

2018-01-01

Introduction Exposure to air pollution impairs aspects of endothelial function such as flow-mediated dilation (FMD). Outdoor exercisers are frequently exposed to air pollution, but how exercising in air pollution affects endothelial function and how these effects are modified by exercise intensity are poorly understood. Objectives Therefore, the purpose of this study was to determine the effects of low-intensity and high-intensity cycling with diesel exhaust (DE) exposure on FMD, blood pressure, plasma nitrite and nitrate (NOx) and endothelin-1. Methods Eighteen males performed 30-minute trials of low or high-intensity cycling (30% and 60% of power at VO2peak) or a resting control condition. For each subject, each trial was performed once while breathing filtered air (FA) and once while breathing DE (300ug/m3 of PM2.5, six trials in total). Preceding exposure, immediately post-exposure, 1 hour and 2 hours post-exposure, FMD, blood pressure and plasma endothelin-1 and NOx concentrations were measured. Data were analyzed using repeated-measures ANOVA and linear mixed model. Results Following exercise in DE, plasma NOx significantly increased and was significantly greater than FA (p<0.05). Two hours following DE exposure, endothelin-1 was significantly less than FA (p = 0.037) but exercise intensity did not modify this response. DE exposure did not affect FMD or blood pressure. Conclusion Our results suggest that exercising in DE did not adversely affect plasma NOX, endothelin-1, FMD and blood pressure. Therefore, recommendations for healthy individuals to moderate or avoid exercise during bouts of high pollution appear to have no acute protective effect. PMID:29466393

Transcutaneous calf-muscle electro-stimulation: A prospective treatment for diabetic claudicants?

PubMed

Ellul, Christian; Gatt, Alfred

2016-11-01

First-line therapy for claudicants with diabetes include supervised exercise programmes to improve walking distance. However, exercise comes with a number of barriers and may be contraindicated in certain conditions. The aim of this study was to evaluate whether calf-muscle electro-stimulation improves claudication distance. A prospective, one-group, pretest-posttest study design was employed on 40 participants living with type 2 diabetes mellitus, peripheral artery disease (ankle-brachial pressure index < 0.90) and calf-muscle claudication. Calf-muscle electro-stimulation of varying frequencies (1-250 Hz) was applied on both ischaemic limbs (N = 80) for 1 h per day for 12 consecutive weeks. The absolute claudication distance was measured at baseline and following the intervention. The cohort (n = 40; 30 males; mean age = 71 years; mean ankle-brachial pressure index = 0.70) registered a mean baseline absolute claudication distance of 333.71 m (standard deviation = 208). Following 91.68 days (standard deviation = 6.23) of electrical stimulation, a significant mean increase of 137 m (standard deviation = 136) in the absolute claudication distance was registered (p = 0.000, Wilcoxon signed rank test). Electrical stimulation of varying low to high frequencies on ischaemic calf muscles significantly increased the maximal walking capacity in claudicants with type 2 diabetes. This therapeutic approach may be considered in patients with impaired exercise tolerance or as an adjunct treatment modality. © The Author(s) 2016.

Sex and Exercise Intensity Do Not Influence Oxygen Uptake Kinetics in Submaximal Swimming

PubMed Central

Reis, Joana F.; Millet, Gregoire P.; Bruno, Paula M.; Vleck, Veronica; Alves, Francisco B.

2017-01-01

The aim of this study was to compare the oxygen uptake (V˙O2) kinetics in front crawl between male and female swimmers at moderate and heavy intensity. We hypothesized that the time constant for the primary phase V˙O2 kinetics was faster in men than in women, for both intensities. Nineteen well trained swimmers (8 females mean ± SD; age 17.9 ± 3.5 years; mass 55.2 ± 3.6 kg; height 1.66 ± 0.05 m and 11 male 21.9 ± 2.8 years; 78.2 ± 11.1 kg; 1.81 ± 0.08 m) performed a discontinuous maximal incremental test and two 600-m square wave transitions for both moderate and heavy intensities to determine the V˙O2 kinetics parameters using mono- and bi-exponential models, respectively. All the tests involved breath-by-breath analysis of front crawl swimming using a swimming snorkel. The maximal oxygen uptake (V˙O2max) was higher in men than in women [4,492 ± 585 ml·min−1 and 57.7 ± 4.4 ml·kg−1·min−1 vs. 2,752.4 ± 187.9 ml·min−1 (p ≤ 0.001) and 50.0 ± 5.7 ml·kg−1·min−1(p = 0.007), respectively]. Similarly, the absolute amplitude of the primary component was higher in men for both intensities (moderate: 1,736 ± 164 vs. 1,121 ± 149 ml·min−1; heavy: 2,948 ± 227 vs. 1,927 ± 243 ml·min−1, p ≤ 0.001, for males and females, respectively). However, the time constant of the primary component (τp) was not influenced by sex (p = 0.527) or swimming intensity (p = 0.804) (moderate: 15.1 ± 5.6 vs. 14.4 ± 5.1 s; heavy: 13.5 ± 3.3 vs. 16.0 ± 4.5 s, for females and males, respectively). The slow component in the heavy domain was not significantly different between female and male swimmers (3.2 ± 2.4 vs. 3.8 ± 1.0 ml·kg−1·min−1, p = 0.476). Overall, only the absolute amplitude of the primary component was higher in men, while the other V˙O2 kinetics parameters were similar between female and male swimmers at both moderate and heavy intensities. The mechanisms underlying these similarities remain unclear. PMID:28239356

Individual preferences for physical exercise as secondary prevention for non-specific low back pain: A discrete choice experiment

PubMed Central

Hagberg, Jan; Axén, Iben; Kwak, Lydia; Lohela-Karlsson, Malin; Skillgate, Eva; Dahlgren, Gunilla; Jensen, Irene

2017-01-01

Background Exercise is effective in improving non-specific low back pain (LBP). Certain components of physical exercise, such as the type, intensity and frequency of exercise, are likely to influence participation among working adults with non-specific LBP, but the value and relative importance of these components remain unknown. The study’s aim was to examine such specific components and their influence on individual preferences for exercise for secondary prevention of non-specific LBP among working adults. Methods In a discrete choice experiment, working individuals with non-specific LBP answered a web-based questionnaire. Each respondent was given ten pairs of hypothetical exercise programs and asked to choose one option from each pair. The choices comprised six attributes of exercise (i.e., type of training, design, intensity, frequency, proximity and incentives), each with either three or four levels. A conditional logit regression that reflected the random utility model was used to analyze the responses. Results The final study population consisted of 112 participants. The participants’ preferred exercise option was aerobic (i.e., cardiovascular) rather than strength training, group exercise with trainer supervision, rather than individual or unsupervised exercise. They also preferred high intensity exercise performed at least once or twice per week. The most popular types of incentive were exercise during working hours and a wellness allowance rather than coupons for sports goods. The results show that the relative value of some attribute levels differed between young adults (age ≤ 44 years) and older adults (age ≥ 45 years) in terms of the level of trainer supervision required, exercise intensity, travel time to exercise location and financial incentives. For active study participants, exercise frequency (i.e., twice per week, 1.15; CI: 0.25; 2.06) influenced choice of exercise. For individuals with more than one child, travel time (i.e., 20 minutes, -0.55; CI: 0.65; 3.26) was also an influential attribute for choice of exercise, showing that people with children at home preferred to exercise close to home. Conclusions This study adds to our knowledge about what types of exercise working adults with back pain are most likely to participate in. The exercise should be a cardiovascular type of training carried out in a group with trainer supervision. It should also be of high intensity and preferably performed twice per week during working hours. Coupons for sports goods do not appear to motivate physical activity among workers with LBP. The findings of the study could have a substantial impact on the planning and development of exercise provision and promotion strategies to improve non-specific LBP. Providers and employers may be able to improve participation in exercise programs for adults with non-specific LBP by focusing on the exercise components which are the most attractive. This in turn would improve satisfaction and adherence to exercise interventions aimed at preventing recurrent non-specific LBP. PMID:29244841

Individual preferences for physical exercise as secondary prevention for non-specific low back pain: A discrete choice experiment.

PubMed

Aboagye, Emmanuel; Hagberg, Jan; Axén, Iben; Kwak, Lydia; Lohela-Karlsson, Malin; Skillgate, Eva; Dahlgren, Gunilla; Jensen, Irene

2017-01-01

Exercise is effective in improving non-specific low back pain (LBP). Certain components of physical exercise, such as the type, intensity and frequency of exercise, are likely to influence participation among working adults with non-specific LBP, but the value and relative importance of these components remain unknown. The study's aim was to examine such specific components and their influence on individual preferences for exercise for secondary prevention of non-specific LBP among working adults. In a discrete choice experiment, working individuals with non-specific LBP answered a web-based questionnaire. Each respondent was given ten pairs of hypothetical exercise programs and asked to choose one option from each pair. The choices comprised six attributes of exercise (i.e., type of training, design, intensity, frequency, proximity and incentives), each with either three or four levels. A conditional logit regression that reflected the random utility model was used to analyze the responses. The final study population consisted of 112 participants. The participants' preferred exercise option was aerobic (i.e., cardiovascular) rather than strength training, group exercise with trainer supervision, rather than individual or unsupervised exercise. They also preferred high intensity exercise performed at least once or twice per week. The most popular types of incentive were exercise during working hours and a wellness allowance rather than coupons for sports goods. The results show that the relative value of some attribute levels differed between young adults (age ≤ 44 years) and older adults (age ≥ 45 years) in terms of the level of trainer supervision required, exercise intensity, travel time to exercise location and financial incentives. For active study participants, exercise frequency (i.e., twice per week, 1.15; CI: 0.25; 2.06) influenced choice of exercise. For individuals with more than one child, travel time (i.e., 20 minutes, -0.55; CI: 0.65; 3.26) was also an influential attribute for choice of exercise, showing that people with children at home preferred to exercise close to home. This study adds to our knowledge about what types of exercise working adults with back pain are most likely to participate in. The exercise should be a cardiovascular type of training carried out in a group with trainer supervision. It should also be of high intensity and preferably performed twice per week during working hours. Coupons for sports goods do not appear to motivate physical activity among workers with LBP. The findings of the study could have a substantial impact on the planning and development of exercise provision and promotion strategies to improve non-specific LBP. Providers and employers may be able to improve participation in exercise programs for adults with non-specific LBP by focusing on the exercise components which are the most attractive. This in turn would improve satisfaction and adherence to exercise interventions aimed at preventing recurrent non-specific LBP.

Negative Affect as a Mediator of the Relationship between Vigorous-Intensity Exercise and Smoking

PubMed Central

Tart, Candyce D.; Leyro, Teresa M.; Richter, Ashley; Zvolensky, Michael J.; Rosenfield, David; Smits, Jasper A. J.

2010-01-01

The present cross-sectional study evaluated whether people who engage in vigorous-intensity exercise are better able to regulate negative affective states, thereby changing core maintenance factors of smoking. Participants were a community sample of adults (n = 270) who completed self-report measures of physical activity, cigarette smoking, anxiety sensitivity, and negative affect. Consistent with hypothesis, vigorous-intensity exercise was related to lower levels of cigarette smoking, accounting for 10% of the variance in smoking. Additionally, negative affect mediated the relationship between vigorous-intensity physical activity and cigarette smoking, accounting for about 12% of this relation. Furthermore, these relationships were stronger for individuals with high anxiety sensitivity than for those with low anxiety sensitivity; including anxiety sensitivity as a moderator of the mediated relationship increased the amount of variance accounted for by negative affect to 17%. The findings are discussed in relation to developing further scientific insight into the mechanisms and pathways relevant to understanding the association among vigorous-intensity exercise, smoking, and emotional vulnerability. PMID:20171786

Absolute band intensities in the nu19/nu23 (530 cm(-1)) and nu7 (777 cm(-1)) bands of acetone ((CH3)2CO) from 232 to 295 K

NASA Technical Reports Server (NTRS)

Wang, W. F.; Stevenson, A.; Reuter, D. C.; Sirota, J. M.

2000-01-01

Absolute band intensities of acetone ((CH3)2CO) in the nu19/nu23 and nu7 band systems near 530 and 777 cm(-1), respectively, were measured at temperatures of 232, 262 and 295 K, using a Fourier transform infrared (FTIR) spectrometer. No evident temperature dependence for the band intensities was observed. The dipole moments and the fundamental band intensities were derived in the harmonic oscillator approximation. The results are useful for the spectroscopic retrieval of acetone concentrations in the upper atmosphere.

Exercise at the Extremes: The Amount of Exercise to Reduce Cardiovascular Events.

PubMed

Eijsvogels, Thijs M H; Molossi, Silvana; Lee, Duck-Chul; Emery, Michael S; Thompson, Paul D

2016-01-26

Habitual physical activity and regular exercise training improve cardiovascular health and longevity. A physically active lifestyle is, therefore, a key aspect of primary and secondary prevention strategies. An appropriate volume and intensity are essential to maximally benefit from exercise interventions. This document summarizes available evidence on the relationship between the exercise volume and risk reductions in cardiovascular morbidity and mortality. Furthermore, the risks and benefits of moderate- versus high-intensity exercise interventions are compared. Findings are presented for the general population and cardiac patients eligible for cardiac rehabilitation. Finally, the controversy of excessive volumes of exercise in the athletic population is discussed. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Heart Rate Variability: Effect of Exercise Intensity on Postexercise Response

ERIC Educational Resources Information Center

James, David V. B.; Munson, Steven C.; Maldonado-Martin, Sara; De Ste Croix, Mark B. A.

2012-01-01

The purpose of the present study was to investigate the influence of two exercise intensities (moderate and severe) on heart rate variability (HRV) response in 16 runners 1 hr prior to (-1 hr) and at +1 hr, +24 hr, +48 hr, and +72 hr following each exercise session. Time domain indexes and a high frequency component showed a significant decrease…

Comparison of Interstitial Fluid pH, PCO2, PO2 with Venous Blood Values During Repetitive Handgrip Exercise

NASA Technical Reports Server (NTRS)

Hagan, Ronald Donald; Soller, Babs R.; Shear, Michael; Walz, Matthias; Landry, Michelle; Heard, Stephen

2006-01-01

We evaluated the use of a small, fiber optic sensor to measure pH, PCO2 and PO2 from forearm muscle interstitial fluid (IF) during handgrip dynamometry. PURPOSE: Compare pH, PCO2 and PO2 values obtained from venous blood with those from the IF of the flexor digitorum superficialis (FDS) during three levels of exercise intensity. METHODS: Six subjects (5M/1F), average age 29+/-5 yrs, participated in the study. A venous catheter was placed in the retrograde direction in the antecubital space and a fiber optic sensor (Paratrend, Diametrics Medical, Inc.) was placed through a 22 G catheter into the FDS muscle under ultrasound guidance. After a 45 min rest period, subjects performed three 5-min bouts of repetitive handgrip exercise (2s contraction/1 s relaxation) at attempted levels of 15%, 30% and 45% of maximal voluntary contraction. The order of the exercise bouts was random with the second and third bouts started after blood lactate had returned to baseline. Venous blood was sampled every minute during exercise and analyzed with an I-Stat CG-4+ cartridge, while IF fiber optic sensor measurements were obtained every 2 s. Change from pre-exercise baseline to end of exercise was computed for pH, PCO2 and PO2. Blood and IF values were compared with a paired t-test. RESULTS: Baseline values for pH, PCO2 and PO2 were 7.37+/-0.02, 46+/-4 mm Hg, and 36+/-6 mm Hg respectively in blood and 7.39+/-0.02, 44+/-6 mm Hg, and 35+/-14 mm Hg in IF. Average changes over all exercise levels are noted in the Table below. For each parameter the exercise-induced change was at least twice as great in IF as in blood. In blood and IF, pH and PCO2 increases were directly related to exercise intensity. Change in venous PO2 was unrelated to exercise intensity, while IF PO2 decreased with increases in exercise intensity. CONCLUSIONS: Measurement of IF pH, PCO2 and PO2 is more sensitive to exercise intensity than measurement of the same parameters in venous blood and provides continuous assessment during and after exercise.

Cardiac parasympathetic reactivation following exercise: implications for training prescription.

PubMed

Stanley, Jamie; Peake, Jonathan M; Buchheit, Martin

2013-12-01

The objective of exercise training is to initiate desirable physiological adaptations that ultimately enhance physical work capacity. Optimal training prescription requires an individualized approach, with an appropriate balance of training stimulus and recovery and optimal periodization. Recovery from exercise involves integrated physiological responses. The cardiovascular system plays a fundamental role in facilitating many of these responses, including thermoregulation and delivery/removal of nutrients and waste products. As a marker of cardiovascular recovery, cardiac parasympathetic reactivation following a training session is highly individualized. It appears to parallel the acute/intermediate recovery of the thermoregulatory and vascular systems, as described by the supercompensation theory. The physiological mechanisms underlying cardiac parasympathetic reactivation are not completely understood. However, changes in cardiac autonomic activity may provide a proxy measure of the changes in autonomic input into organs and (by default) the blood flow requirements to restore homeostasis. Metaboreflex stimulation (e.g. muscle and blood acidosis) is likely a key determinant of parasympathetic reactivation in the short term (0-90 min post-exercise), whereas baroreflex stimulation (e.g. exercise-induced changes in plasma volume) probably mediates parasympathetic reactivation in the intermediate term (1-48 h post-exercise). Cardiac parasympathetic reactivation does not appear to coincide with the recovery of all physiological systems (e.g. energy stores or the neuromuscular system). However, this may reflect the limited data currently available on parasympathetic reactivation following strength/resistance-based exercise of variable intensity. In this review, we quantitatively analyse post-exercise cardiac parasympathetic reactivation in athletes and healthy individuals following aerobic exercise, with respect to exercise intensity and duration, and fitness/training status. Our results demonstrate that the time required for complete cardiac autonomic recovery after a single aerobic-based training session is up to 24 h following low-intensity exercise, 24-48 h following threshold-intensity exercise and at least 48 h following high-intensity exercise. Based on limited data, exercise duration is unlikely to be the greatest determinant of cardiac parasympathetic reactivation. Cardiac autonomic recovery occurs more rapidly in individuals with greater aerobic fitness. Our data lend support to the concept that in conjunction with daily training logs, data on cardiac parasympathetic activity are useful for individualizing training programmes. In the final sections of this review, we provide recommendations for structuring training microcycles with reference to cardiac parasympathetic recovery kinetics. Ultimately, coaches should structure training programmes tailored to the unique recovery kinetics of each individual.

Exercise and end-stage kidney disease: functional exercise capacity and cardiovascular outcomes.

PubMed

Parsons, Trisha L; King-Vanvlack, Cheryl E

2009-11-01

This review examined published reports of the impact of extradialytic and intradialytic exercise programs on physiologic aerobic exercise capacity, functional exercise endurance, and cardiovascular outcomes in individuals with ESKD. Studies spanning 30 years from the first published report of exercise in the ESKD population were reviewed. Studies conducted in the first half of the publication record focused on the efficacy of exercise training programs performed "off"-dialysis with respect to the modification of traditional cardiovascular risk factors, aerobic capacity, and its underlying determinants. In the latter half of the record, there had been a shift to include other client-centered goals such as physical function and quality of life. There is evidence that both intra- and extradialytic programs can significantly enhance aerobic exercise capacity, but moderate-intensity extradialytic programs may result in greater gains in those individuals who initially have extremely poor aerobic capacity. Functionally, substantive improvements in exercise endurance in excess of the minimum clinical significant difference can occur following either low- or moderate-intensity exercise regardless of the initial level of performance. Reductions in blood pressure and enhanced vascular functioning reported after predominantly intradialytic exercise programs suggest that either low- or moderate-intensity exercise programs can confer cardiovascular benefit. Regardless of prescription model, there was an overall lack of evidence regarding the impact of exercise-induced changes in exercise capacity, endurance, and cardiovascular function on a number of relevant health outcomes (survival, morbidity, and cardiovascular risk), and, more importantly, there is no evidence on the long-term impact of exercise and/or physical activity interventions on these health outcomes.

Effects of Different Heavy-Resistance Exercise Protocols on Plasma Beta-Endorphin Concentrations

DTIC Science & Technology

1993-01-01

of O-EP and cortisol. forms of high-intensity exercise, which is performed well above the level that produces V02 .. but uses multi- anaerobic ; opioid...utilizing the Borg CR- ing the rest period length (i.e., from I to 3 min; or in- 10 scale designed to accommodate primarily anaerobic creasing the resistance...O-EP in response to though short-term anaerobic exercise to exhaustion has high-intensity exercise remain unknown, it has been sug- been shown to

A Single Bout of Moderate Aerobic Exercise Improves Motor Skill Acquisition.

PubMed

Statton, Matthew A; Encarnacion, Marysol; Celnik, Pablo; Bastian, Amy J

2015-01-01

Long-term exercise is associated with improved performance on a variety of cognitive tasks including attention, executive function, and long-term memory. Remarkably, recent studies have shown that even a single bout of aerobic exercise can lead to immediate improvements in declarative learning and memory, but less is known about the effect of exercise on motor learning. Here we sought to determine the effect of a single bout of moderate intensity aerobic exercise on motor skill learning. In experiment 1, we investigated the effect of moderate aerobic exercise on motor acquisition. 24 young, healthy adults performed a motor learning task either immediately after 30 minutes of moderate intensity running, after running followed by a long rest period, or after slow walking. Motor skill was assessed via a speed-accuracy tradeoff function to determine how exercise might differentially affect two distinct components of motor learning performance: movement speed and accuracy. In experiment 2, we investigated both acquisition and retention of motor skill across multiple days of training. 20 additional participants performed either a bout of running or slow walking immediately before motor learning on three consecutive days, and only motor learning (no exercise) on a fourth day. We found that moderate intensity running led to an immediate improvement in motor acquisition for both a single session and on multiple sessions across subsequent days, but had no effect on between-day retention. This effect was driven by improved movement accuracy, as opposed to speed. However, the benefit of exercise was dependent upon motor learning occurring immediately after exercise-resting for a period of one hour after exercise diminished the effect. These results demonstrate that moderate intensity exercise can prime the nervous system for the acquisition of new motor skills, and suggest that similar exercise protocols may be effective in improving the outcomes of movement rehabilitation programs.

A randomized comparison study regarding the impact of short-duration, high-intensity exercise and traditional exercise on anthropometric and body composition measurement changes in post-menopausal women--A pilot study.

PubMed

Grossman, Joan A Cebrick; Payne, Ellen K

2016-03-01

The mode and duration of exercise necessary to change body composition and reduce weight remains debatable. Menopause results in hormonal changes that preclude weight loss. This randomized pilot study compared the effects of short-duration, high-intensity interval training and traditional exercise on anthropometric and body composition measurement changes in post-menopausal women. To compare the effects of short-duration, high-intensity interval training and traditional methods of exercise (walking) on anthropometric, body composition and body weight change over a 12-week period. Subjects (N = 18) were post-menopausal, sedentary female volunteers, randomly assigned into one of two exercise groups. Both groups exercised five out of seven days for 12 weeks. The resistance group (n = 8) (54.3 ± 7.3 years; BMI = 28.0 ± 2.1 kg/m(2); mean ± SD) exercised for 15.0 ± 3.5 min, which consisted of five different exercise routines including upper and lower extremity, a cardio segment, yoga and abdominal exercises. The walkers (n = 10) (56.6 ± 5.2 years; BMI = 29.2 ± 2.6 kg/m(2); mean ± SD) exercised for 40.0 ± 5.0 min at 65% of their age-predicted maximum heart rate. Relative (%) body fat was measured via DEXA scan, along with five anthropometric measurements, all of which were taken prior to and after 12 weeks. Independent sample t-tests were probed for differences, p ≤ 0.05. No statistically significant changes were determined between the groups for pre-and post-measurements. The outcomes of this study provide a foundation for future comparisons of short-duration high-intensity interval training exercise and traditional exercise, or walking, on anthropometric and body composition measurement changes in sedentary, overweight, post-menopausal females over a 12-week period. © The Author(s) 2016.

Safety of American Heart Association-recommended minimum exercise for desmosomal mutation carriers.

PubMed

Sawant, Abhishek C; Te Riele, Anneline S J M; Tichnell, Crystal; Murray, Brittney; Bhonsale, Aditya; Tandri, Harikrishna; Judge, Daniel P; Calkins, Hugh; James, Cynthia A

2016-01-01

Endurance exercise is associated with adverse outcomes in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Exercise recommendations for family members remain undetermined. The purposes of this study were to determine if (1) endurance exercise (Bethesda class C) and exercise intensity (metabolic equivalent hours per year [MET-Hr/year]) increase the likelihood of fulfilling 2010 Task Force Criteria and ventricular arrhythmias/implantable cardioverter-defibrillator shock (ventricular tachycardia/ventricular fibrillation [VT/VF]), and (2) exercise restriction to the American Heart Association (AHA)-recommended minimum for healthy adults is associated with favorable outcomes of at-risk family members. Twenty-eight family members of 10 probands inheriting a PKP2 mutation were interviewed about exercise from age 10. Exercise threshold to maintain overall health was based on the 2007 AHA guidelines of a minimum 390 to 650 MET-Hr/year. After adjustment for age, sex, and family membership, both participation in endurance athletics (odds ratio [OR] 7.4, P = .03) and higher-intensity exercise (OR = 4.2, P = .004) were associated with diagnosis (n = 13). Endurance athletes were also significantly more likely to develop VT/VF (n = 6, P = .02). Family members who restricted exercise at or below the upper bound of the AHA goal (≤650 MET-Hr/year) were significantly less likely to be diagnosed (OR = 0.07, P = .002) and had no VT/VF. At diagnosis and first VT/VF, family members had accumulated 2.8-fold (P = .002) and 3.5-fold (P = .03), respectively, greater MET-Hr exercise than the AHA-recommended minimum. Those who developed VT/VF had performed particularly high-intensity exercise in adolescence compared to unaffected family members (age 10-14: P = .04; age 14-19: P = .02). The results of this study suggest restricting unaffected desmosomal mutation carriers from endurance and high-intensity athletics but potentially not from AHA-recommended minimum levels of exercise for healthy adults. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Predictors of exercise capacity following exercise-based rehabilitation in patients with coronary heart disease and heart failure: A meta-regression analysis.

PubMed

Uddin, Jamal; Zwisler, Ann-Dorthe; Lewinter, Christian; Moniruzzaman, Mohammad; Lund, Ken; Tang, Lars H; Taylor, Rod S

2016-05-01

The aim of this study was to undertake a comprehensive assessment of the patient, intervention and trial-level factors that may predict exercise capacity following exercise-based rehabilitation in patients with coronary heart disease and heart failure. Meta-analysis and meta-regression analysis. Randomized controlled trials of exercise-based rehabilitation were identified from three published systematic reviews. Exercise capacity was pooled across trials using random effects meta-analysis, and meta-regression used to examine the association between exercise capacity and a range of patient (e.g. age), intervention (e.g. exercise frequency) and trial (e.g. risk of bias) factors. 55 trials (61 exercise-control comparisons, 7553 patients) were included. Following exercise-based rehabilitation compared to control, overall exercise capacity was on average 0.95 (95% CI: 0.76-1.41) standard deviation units higher, and in trials reporting maximum oxygen uptake (VO2max) was 3.3 ml/kg.min(-1) (95% CI: 2.6-4.0) higher. There was evidence of a high level of statistical heterogeneity across trials (I(2) statistic > 50%). In multivariable meta-regression analysis, only exercise intervention intensity was found to be significantly associated with VO2max (P = 0.04); those trials with the highest average exercise intensity had the largest mean post-rehabilitation VO2max compared to control. We found considerable heterogeneity across randomized controlled trials in the magnitude of improvement in exercise capacity following exercise-based rehabilitation compared to control among patients with coronary heart disease or heart failure. Whilst higher exercise intensities were associated with a greater level of post-rehabilitation exercise capacity, there was no strong evidence to support other intervention, patient or trial factors to be predictive. © The European Society of Cardiology 2015.

The effects of light emitting diode therapy following high intensity exercise.

PubMed

Denis, Romain; O'Brien, Christopher; Delahunt, Eamonn

2013-05-01

To determine the effects of light emitting diode therapy (LEDT) irradiation on blood lactate concentration ([La]) clearance, peak power output and fatigue index (FI) following high intensity fatiguing exercise. Single-blinded randomised cross-over placebo controlled trial. University College Dublin, Institute for Sport and Health, Human performance laboratory. Eighteen healthy male athletes were recruited from field-based sports (including soccer, hockey and rugby union) and participated in the present study. Dependent variables were the peak power output elicited during the Wingate Anaerobic Test (WAnT), FI and [La] before and after each exercise. WAnT performance was measured prior to high intensity fatiguing exercise (Yo-Yo IR2), prior to LEDT or placebo, and following LEDT or placebo. [La] was measured at baseline, immediately after the Yo-Yo IR2, and in the 3rd, 9th, and 15th min following LEDT or placebo condition. No significant group by treatment interactions were observed for any outcome measures (P > 0.05). We conclude that LEDT irradiation applied following high intensity exercise was not effective and has no immediate effect on [La] clearance, peak power and FI, and thus has no significant effect on muscle recovery in athletes at the intensity and irradiation parameters used in the present study. Further research using different parameters is required to determine how LEDT may contribute to post-exercise recovery. Copyright © 2012 Elsevier Ltd. All rights reserved.

Work, exercise, and space flight. 3: Exercise devices and protocols

NASA Technical Reports Server (NTRS)

Thornton, William

1989-01-01

Preservation of locomotor capacity by earth equivalent, exercise in space is the crucial component of inflight exercise. At this time the treadmill appears to be the only way possible to do this. Work is underway on appropriate hardware but this and a proposed protocol to reduce exercise time must be tested. Such exercise will preserve muscle, bone Ca(++) and cardiovascular-respiratory capacity. In addition, reasonable upper body exercise can be supplied by a new force generator/measurement system-optional exercise might include a rowing machine and bicycle ergometer. A subject centered monitoring-evaluation program will allow real time adjustments as required. Absolute protection for any astronaut will not be possible and those with hypertrophied capacities such as marathoners or weight lifters will suffer significant loss. However, the program described should return the crew to earth with adequate capacity of typical activity on earth including immediate ambulation and minimal recovery time and without permanent change. An understanding of the practical mechanics and biomechanics involved is essential to a solution of the problem.

Identification of anaerobic threshold by analysis of heart rate variability during discontinuous dynamic and resistance exercise protocols in healthy older men.

PubMed

Simões, Rodrigo Polaquini; Castello-Simões, Viviane; Mendes, Renata Gonçalves; Archiza, Bruno; Dos Santos, Daniel Augusto; Bonjorno, José Carlos; de Oliveira, Claudio Ricardo; Catai, Aparecida Maria; Arena, Ross; Borghi-Silva, Audrey

2014-03-01

The purposes of this study were to determine anaerobic threshold (AT) during discontinuous dynamic and resistive exercise protocols by analysing of heart rate variability (HRV) and blood lactate (BL) in healthy elderly subjects and compare the cardiovascular, metabolic and autonomic variables obtained from these two forms of exercise. Fourteen elderly (70 ± 4 years) apparently healthy males underwent the following tests: (i) incremental ramp test on cycle ergometer, (ii) one repetition maximum (1RM) leg press at 45°, (iii) a discontinuous exercise test on a cycle ergometer (DET-C) protocol and (iv) a resistance exercise leg press (DET-L) protocol. Heart rate, blood pressure and BL were obtained during each increment of exercise intensity. No significant differences (P>0·05) were found between methods of AT determination (BL and HRV) nor the relative intensity corresponding to AT (30% of maximum intensity) between the types of exercise (DET-C and DET-L). Furthermore, no significant differences (P>0·05) were found between the DET-C and DET-L in relation to HRV, however, the DET-L provided higher values of systolic blood pressure and BL (P<0·05) from the intensity corresponding to AT. We conclude that HRV was effective in determination of AT, and the parasympathetic modulation responses obtained during dynamic and resistive exercise protocols were similar when compared at the same relative intensity. However, DET-L resulted in higher values of blood pressure and BL at workloads beyond AT. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Effect of ubiquinol supplementation on biochemical and oxidative stress indexes after intense exercise in young athletes.

PubMed

Orlando, Patrick; Silvestri, Sonia; Galeazzi, Roberta; Antonicelli, Roberto; Marcheggiani, Fabio; Cirilli, Ilenia; Bacchetti, Tiziana; Tiano, Luca

2018-12-01

Physical exercise significantly impacts the biochemistry of the organism. Ubiquinone is a key component of the mitochondrial respiratory chain and ubiquinol, its reduced and active form, is an emerging molecule in sport nutrition. The aim of this study was to evaluate the effect of ubiquinol supplementation on biochemical and oxidative stress indexes after an intense bout of exercise. 21 male young athletes (26 + 5 years of age) were randomized in two groups according to a double blind cross-over study, either supplemented with ubiquinol (200 mg/day) or placebo for 1 month. Blood was withdrawn before and after a single bout of intense exercise (40 min run at 85% maxHR). Physical performance, hematochemical parameters, ubiquinone/ubiquinol plasma content, intracellular reactive oxygen species (ROS) level, mitochondrial membrane depolarization, paraoxonase activity and oxidative DNA damage were analyzed. A single bout of intense exercise produced a significant increase in most hematochemical indexes, in particular CK and Mb while, on the contrary, normalized coenzyme Q 10 plasma content decreased significantly in all subjects. Ubiquinol supplementation prevented exercise-induced CoQ deprivation and decrease in paraoxonase activity. Moreover at a cellular level, in peripheral blood mononuclear cells, ubiquinol supplementation was associated with a significant decrease in cytosolic ROS while mitochondrial membrane potential and oxidative DNA damage remained unchanged. Data highlights a very rapid dynamic of CoQ depletion following intense exercise underlying an increased demand by the organism. Ubiquinol supplementation minimized exercise-induced depletion and enhanced plasma and cellular antioxidant levels but it was not able to improve physical performance indexes or markers of muscular damage.

Intensive training and reduced volume increases muscle FXYD1 expression and phosphorylation at rest and during exercise in athletes

PubMed Central

Thomassen, Martin; Gunnarsson, Thomas P.; Christensen, Peter M.; Pavlovic, Davor; Shattock, Michael J.

2016-01-01

The present study examined the effect of intensive training in combination with marked reduction in training volume on phospholemman (FXYD1) expression and phosphorylation at rest and during exercise. Eight well-trained cyclists replaced their regular training with speed-endurance training (10–12 × ∼30-s sprints) two or three times per week and aerobic high-intensity training (4–5 × 3–4 min at 90–95% of peak aerobic power output) 1–2 times per week for 7 wk and reduced the training volume by 70%. Muscle biopsies were obtained before and during a repeated high-intensity exercise protocol, and protein expression and phosphorylation were determined by Western blot analysis. Expression of FXYD1 (30%), actin (40%), mammalian target of rapamycin (mTOR) (12%), phospholamban (PLN) (16%), and Ca2+/calmodulin-dependent protein kinase II (CaMKII) γ/δ (25%) was higher (P < 0.05) than before the training intervention. In addition, after the intervention, nonspecific FXYD1 phosphorylation was higher (P < 0.05) at rest and during exercise, mainly achieved by an increased FXYD1 Ser-68 phosphorylation, compared with before the intervention. CaMKII, Thr-287, and eukaryotic elongation factor 2 Thr-56 phosphorylation at rest and during exercise, overall PKCα/β, Thr-638/641, and mTOR Ser-2448 phosphorylation during repeated intense exercise as well as resting PLN Thr-17 phosphorylation were also higher (P < 0.05) compared with before the intervention period. Thus, a period of high-intensity training with reduced training volume increases expression and phosphorylation levels of FXYD1, which may affect Na+/K+ pump activity and muscle K+ homeostasis during intense exercise. Furthermore, higher expression of CaMKII and PLN, as well as increased phosphorylation of CaMKII Thr-287 may have improved intracellular Ca2+ handling. PMID:26791827

Intensive training and reduced volume increases muscle FXYD1 expression and phosphorylation at rest and during exercise in athletes.

PubMed

Thomassen, Martin; Gunnarsson, Thomas P; Christensen, Peter M; Pavlovic, Davor; Shattock, Michael J; Bangsbo, Jens

2016-04-01

The present study examined the effect of intensive training in combination with marked reduction in training volume on phospholemman (FXYD1) expression and phosphorylation at rest and during exercise. Eight well-trained cyclists replaced their regular training with speed-endurance training (10-12 × ∼30-s sprints) two or three times per week and aerobic high-intensity training (4-5 × 3-4 min at 90-95% of peak aerobic power output) 1-2 times per week for 7 wk and reduced the training volume by 70%. Muscle biopsies were obtained before and during a repeated high-intensity exercise protocol, and protein expression and phosphorylation were determined by Western blot analysis. Expression of FXYD1 (30%), actin (40%), mammalian target of rapamycin (mTOR) (12%), phospholamban (PLN) (16%), and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) γ/δ (25%) was higher (P < 0.05) than before the training intervention. In addition, after the intervention, nonspecific FXYD1 phosphorylation was higher (P < 0.05) at rest and during exercise, mainly achieved by an increased FXYD1 Ser-68 phosphorylation, compared with before the intervention. CaMKII, Thr-287, and eukaryotic elongation factor 2 Thr-56 phosphorylation at rest and during exercise, overall PKCα/β, Thr-638/641, and mTOR Ser-2448 phosphorylation during repeated intense exercise as well as resting PLN Thr-17 phosphorylation were also higher (P < 0.05) compared with before the intervention period. Thus, a period of high-intensity training with reduced training volume increases expression and phosphorylation levels of FXYD1, which may affect Na(+)/K(+) pump activity and muscle K(+) homeostasis during intense exercise. Furthermore, higher expression of CaMKII and PLN, as well as increased phosphorylation of CaMKII Thr-287 may have improved intracellular Ca(2+) handling. Copyright © 2016 the American Physiological Society.

Social Bonds and Exercise: Evidence for a Reciprocal Relationship

PubMed Central

Davis, Arran; Taylor, Jacob; Cohen, Emma

2015-01-01

In two experimental studies, we investigated mechanisms hypothesized to underpin two pervasive and interrelated phenomena: that certain forms of group movement and exercise lead to social bonding and that social bonding can lead to enhanced exercise performance. In Study 1, we manipulated synchrony and exercise intensity among rowers and found that, compared with low intensity exercise, moderate intensity exercise led to significantly higher levels of cooperation in an economic game; no effect of synchrony vs. non-synchrony was found. In Study 2, we investigated the effects of bonding on performance, using synchrony as a cue of existing supportive social bonds among participants. An elite, highly bonded team of rugby players participated in solo, synchronized, and non-synchronized warm-up sessions; participants' anaerobic performance significantly improved after the brief synchronous warm-up relative to the non-synchronous warm-up. The findings substantiate claims concerning the reciprocal links between group exercise and social bonding, and may help to explain the ubiquity of collective physical activity across cultural domains as varied as play, ritual, sport, and dance. PMID:26317514

Blood flow measurement of human skeletal muscle during various exercise intensity using diffuse correlation spectroscopy (DCS)

NASA Astrophysics Data System (ADS)

Murakami, Yuya; Ono, Yumie; Ichinose, Masashi

2017-02-01

We studied blood flow dynamics of active skeletal muscle using diffuse correlation spectroscopy (DCS), an emerging optical modality that is suitable for noninvasive quantification of microcirculation level in deep tissue. Seven healthy subjects conducted 0.5 Hz dynamic handgrip exercise for 3 minutes at intensities of 10, 20, 30, and 50 % of maximal voluntary contraction (MVC). DCS could detect the time-dependent increase of the blood flow response of the forearm muscle for continuous exercises, and the increase ratios of the mean blood flow through the exercise periods showed good correlation with the exercise intensities. We also compared blood flow responses detected from DCS with two different photon sampling rates and found that an appropriate photon sampling rates should be selected to follow the wide-ranged increase in the muscle blood flow with dynamic exercise. Our results demonstrate the possibility for utilizing DCS in a field of sports medicine to noninvasively evaluate the dynamics of blood flow in the active muscles.

A preliminary, randomized trial of aerobic exercise for alcohol dependence.

PubMed

Brown, Richard A; Abrantes, Ana M; Minami, Haruka; Read, Jennifer P; Marcus, Bess H; Jakicic, John M; Strong, David R; Dubreuil, Mary Ella; Gordon, Alan A; Ramsey, Susan E; Kahler, Christopher W; Stuart, Gregory L

2014-07-01

Interventions targeting physical activity may be valuable as an adjunct to alcohol treatment, but have been relatively untested. In the current study, alcohol dependent, physically sedentary patients were randomized to: a 12-week moderate-intensity, group aerobic exercise intervention (AE; n=25) or a brief advice to exercise intervention (BA-E; n=23). Results showed that individuals in AE reported significantly fewer drinking and heavy drinking days, relative to BA-E during treatment. Furthermore adherence to AE strengthened the beneficial effect of intervention on alcohol use outcomes. While high levels of moderate-intensity exercise appeared to facilitate alcohol recovery regardless of intervention arm, attending the group-based AE intervention seemed to further enhance the positive effects of exercise on alcohol use. Study findings indicate that a moderate intensity, group aerobic exercise intervention is an efficacious adjunct to alcohol treatment. Improving adherence to the intervention may enhance its beneficial effects on alcohol use. Copyright © 2014 Elsevier Inc. All rights reserved.

Remotely controlled biking is associated with improved adherence to prescribed cycling speed.

PubMed

Jeong, In Cheol; Finkelstein, Joseph

2015-01-01

Individuals with mobility impairment may benefit from passive exercise mode which can be subsequently enhanced by an active exercise program. However, it is unclear which exercise mode promotes higher adherence to prescribed exercise intensity. The goal of this project was to compare adherence to prescribed speed during passive and active cycling exercise. We used cross-over study design in which subjects followed the same cycling intensity prescription for passive and active exercise modes in a random sequence. Coefficient of variation (CV) and speed differences were used to estimate extent of deviation from the prescribed trajectory. CV varied from 5.2% to 20.4% for the active mode and from 2.8% to 4.5% for the passive mode respectively. Though the CV differences did not reach statistical significance, analysis of cycling speed adherence of 120-second periods showed significantly higher cycling adherence during passive mode for each target cycling speed. Our results indicated that the passive mode may promote exercise safety and efficacy by helping patients who have safety concerns such as the frail elderly, patients with cardiovascular conditions or people with other contraindications for excessive exertion during exercise, in following the optimal intensity trajectory prescribed by their provider.

Leisure-time, occupational, and commuting physical activity and risk of type 2 diabetes in Japanese workers: a cohort study.

PubMed

Honda, Toru; Kuwahara, Keisuke; Nakagawa, Tohru; Yamamoto, Shuichiro; Hayashi, Takeshi; Mizoue, Tetsuya

2015-10-02

Physical activity has been suggested to reduce the risk of type 2 diabetes. However, evidence is limited regarding whether vigorous-intensity activity yields the same benefits in preventing type 2 diabetes compared with an equivalent dose of moderate-intensity activity as well as other type of physical activity. We examined the risk of type 2 diabetes associated with exercise intensity during leisure and occupational and commuting physical activity among Japanese individuals. Participants included 26,628 workers (23,207 men and 3,421 women) aged 30 to 64 years without diabetes at baseline. There was 6 years of follow-up maximum. Leisure-time exercise, occupational physical activity, and duration of walking to and from work were self-reported. Diabetes was diagnosed by using HbA1c, fasting or random blood glucose, and self-report. We used Cox regression analysis to estimate the hazard ratio (HR) and the 95% confidence interval (CI) of incident diabetes. During a mean follow-up of 5.2 years, 1,770 participants developed type 2 diabetes. Compared with individuals who engaged in no exercise, the HRs (95% CIs) for <7.5, 7.5 to <15.0, and ≥15.0 MET-hours per week of exercise were 0.94 (0.81, 1.08), 1.07 (0.88, 1.30), and 0.90 (0.67, 1.21), respectively, among individuals who engaged in moderate-intensity exercise alone; 0.68 (0.44, 1.06), 0.86 (0.54, 1.34), and 0.89 (0.56, 1.41), respectively, among individuals who engaged in vigorous-intensity exercise alone; and 0.70 (0.44, 1.11), 0.57 (0.37, 0.90), and 0.76 (0.52, 1.11), respectively, among individuals who engaged in the two intensities, with adjustments for potential confounders and the total volume of exercise. Occupational physical activity and walking to and from work were not associated with diabetes. The results suggest that vigorous-intensity exercise can reduce the risk of type 2 diabetes among Japanese workers.

[Effect of high-intensity interval training on the reduction of glycosylated hemoglobin in type-2 diabetic adult patients].

PubMed

Aguilera Eguía, Raúl Alberto; Russell Guzmán, Javier Antonio; Soto Muñoz, Marcelo Enrique; Villegas González, Bastián Eduardo; Poblete Aro, Carlos Emilio; Ibacache Palma, Alejandro

2015-03-05

Type 2 diabetes mellitus is one of the major non-communicable chronic diseases in the world. Its prevalence in Chile is significant, and complications associated with this disease involve great costs, which is why prevention and treatment of this condition are essential. Physical exercise is an effective means for prevention and treatment of type 2 diabetes mellitus. The emergence of new forms of physical training, such as "high intensity interval training", presents novel therapeutic alternatives for patients and health care professionals. To assess the validity and applicability of the results regarding the effectiveness of high intensity interval training in reducing glycosylated hemoglobin in adult patients with type 2 diabetes mellitus and answer the following question: In subjects with type 2 diabetes, can the method of high intensity interval training compared to moderate intensity exercise decrease glycosylated hemoglobin? We performed a critical analysis of the article "Feasibility and preliminary effectiveness of high intensity interval training in type 2 diabetes". We found no significant differences in the amount of glycosylated hemoglobin between groups of high intensity interval training and moderate-intensity exercise upon completion of the study (p>0.05). In adult patients with type 2 diabetes mellitus, high intensity interval training does not significantly improve glycosylated hemoglobin levels. Despite this, the high intensity interval training method shows as much improvement in body composition and physical condition as the moderate intensity exercise program.