Science.gov

Sample records for absolute exercise intensity

  1. Muscle Activation During Exercise in Severe Acute Hypoxia: Role of Absolute and Relative Intensity

    PubMed Central

    Torres-Peralta, Rafael; Losa-Reyna, José; González-Izal, Miriam; Perez-Suarez, Ismael; Calle-Herrero, Jaime; Izquierdo, Mikel

    2014-01-01

    Abstract Torres-Peralta, Rafael, José Losa-Reyna, Miriam González-Izal, Ismael Perez-Suarez, Jaime Calle-Herrero, Mikel Izquierdo, and José A.L. Calbet. Muscle activation during exercise in severe acute hypoxia: Role of absolute and relative intensity. High Alt Med Biol 15:472–482, 2014.—The aim of this study was to determine the influence of severe acute hypoxia on muscle activation during whole body dynamic exercise. Eleven young men performed four incremental cycle ergometer tests to exhaustion breathing normoxic (FIo2=0.21, two tests) or hypoxic gas (FIo2=0.108, two tests). Surface electromyography (EMG) activities of rectus femoris (RF), vastus medialis (VL), vastus lateralis (VL), and biceps femoris (BF) were recorded. The two normoxic and the two hypoxic tests were averaged to reduce EMG variability. Peak Vo2 was 34% lower in hypoxia than in normoxia (p<0.05). The EMG root mean square (RMS) increased with exercise intensity in all muscles (p<0.05), with greater effect in hypoxia than in normoxia in the RF and VM (p<0.05), and a similar trend in VL (p=0.10). At the same relative intensity, the RMS was greater in normoxia than in hypoxia in RF, VL, and BF (p<0.05), with a similar trend in VM (p=0.08). Median frequency increased with exercise intensity (p<0.05), and was higher in hypoxia than in normoxia in VL (p<0.05). Muscle contraction burst duration increased with exercise intensity in VM and VL (p<0.05), without clear effects of FIo2. No significant FIo2 effects on frequency domain indices were observed when compared at the same relative intensity. In conclusion, muscle activation during whole body exercise increases almost linearly with exercise intensity, following a muscle-specific pattern, which is adjusted depending on the FIo2 and the relative intensity of exercise. Both VL and VM are increasingly involved in power output generation with the increase of intensity and the reduction in FIo2. PMID:25225839

  2. STS-9 Shuttle grow - Ram angle effect and absolute intensities

    NASA Technical Reports Server (NTRS)

    Swenson, G. R.; Mende, S. B.; Clifton, K. S.

    1986-01-01

    Visible imagery from Space Shuttle mission STS-9 (Spacelab 1) has been analyzed for the ram angle effect and the absolute intensity of glow. The data are compared with earlier measurements and the anomalous high intensities at large ram angles are confirmed. Absolute intensities of the ram glow on the shuttle tile, at 6563 A, are observed to be about 20 times more intense than those measured on the AE-E spacecraft. Implications of these observations for an existing theory of glow involving NO2 are presented.

  3. Measurement of Disintegration Rates and Absolute {gamma}-ray Intensities

    SciTech Connect

    DeVries, Daniel J.; Griffin, Henry C.

    2006-03-13

    The majority of practical radioactive materials decay by modes that include {gamma}-ray emission. For questions of 'how much' or 'how pure', one must know the absolute intensities of the major radiations. We are using liquid scintillation counting (LSC) to measurements of disintegration rates, coupled with {gamma}-ray spectroscopy to measure absolute {gamma}-ray emission probabilities. Described is a study of the 227Th chain yielding absolute {gamma}-ray intensities with {approx}0.5% accuracy and information on LSC efficiencies.

  4. Exercise intensity prescription during heat stress: A brief review.

    PubMed

    Wingo, J E

    2015-06-01

    Exercise intensity can be prescribed using a variety of indices, such as rating of perceived exertion, heart rate, levels of absolute intensity (e.g., metabolic equivalents), and levels of relative intensity [e.g., percentage of maximal aerobic capacity (% V ˙ O 2 m a x ) or percentage of oxygen uptake reserve (% V ˙ O 2 R )]. Heart rate has a linear relationship with oxygen uptake, is easy to measure, and requires relatively inexpensive monitoring equipment, so it is commonly used to monitor exercise intensity. During heat stress, however, cardiovascular adjustments - including a rise in heart rate that is disproportionate to absolute intensity - result in diminished aerobic capacity and performance. These adjustments include cardiovascular drift, the progressive rise in heart rate and fall in stroke volume over time during prolonged, constant-rate exercise. A variety of factors have been shown to modulate the magnitude of cardiovascular drift, e.g., hyperthermia, dehydration, exercise intensity, and ambient temperature. Regardless of the mode of manipulation, decreases in stroke volume with cardiovascular drift are associated with proportionally similar decreases in V ˙ O 2 m a x , which affects the relationship between heart rate and relative metabolic intensity (% V ˙ O 2 m a x or % V ˙ O 2 R ). This review summarizes the current state of knowledge regarding the influence of cardiovascular drift and reduced V ˙ O 2 m a x on exercise intensity prescription in hot conditions.

  5. Ion chambers simplify absolute intensity measurements in the vacuum ultraviolet

    NASA Technical Reports Server (NTRS)

    Sampson, J. A. R.

    1966-01-01

    Single or double ion chamber technique measures absolute radiation intensities in the extreme vacuum ultraviolet region of the spectrum. The ion chambers use rare gases as the ion carrier. Photon absorbed by the gas creates one ion pair so a measure of these is a measure of the number of incident photons.

  6. 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. PMID:26553495

  7. 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.

  8. 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. PMID:22080319

  9. Use of intensity quotients and differences in absolute structure refinement.

    PubMed

    Parsons, Simon; Flack, Howard D; Wagner, Trixie

    2013-06-01

    Several methods for absolute structure refinement were tested using single-crystal X-ray diffraction data collected using Cu Kα radiation for 23 crystals with no element heavier than oxygen: conventional refinement using an inversion twin model, estimation using intensity quotients in SHELXL2012, estimation using Bayesian methods in PLATON, estimation using restraints consisting of numerical intensity differences in CRYSTALS and estimation using differences and quotients in TOPAS-Academic where both quantities were coded in terms of other structural parameters and implemented as restraints. The conventional refinement approach yielded accurate values of the Flack parameter, but with standard uncertainties ranging from 0.15 to 0.77. The other methods also yielded accurate values of the Flack parameter, but with much higher precision. Absolute structure was established in all cases, even for a hydrocarbon. The procedures in which restraints are coded explicitly in terms of other structural parameters enable the Flack parameter to correlate with these other parameters, so that it is determined along with those parameters during refinement. PMID:23719469

  10. International exercise on 124Sb photon emission intensities determination.

    PubMed

    Bé, M-M; Chauvenet, B; Amiot, M-N; Bobin, C; Lépy, M-C; Branger, T; Lanièce, I; Luca, A; Sahagia, M; Wätjen, A C; Kossert, K; Ott, O; Nähle, O; Dryák, P; Sochorovà, J; Kovar, P; Auerbach, P; Altzitzoglou, T; Pommé, S; Sibbens, G; Van Ammel, R; Paepen, J; Iwahara, A; Delgado, J U; Poledna, R

    2010-10-01

    An international exercise, registered as EUROMET project no. 907, was launched to measure both the activity of a solution of (124)Sb and the photon emission intensities of its decay. The same solution was sent by LNE-LNHB to eight participating laboratories, six of which sent results for photon emission intensities both in absolute and in relative terms. From these results and including previous published values, a consistent decay scheme was worked out, proving that problems in activity measurements have not been due to decay scheme data.

  11. Gait Recognition and Walking Exercise Intensity Estimation

    PubMed Central

    Lin, Bor-Shing; Liu, Yu-Ting; Yu, Chu; Jan, Gene Eu; Hsiao, Bo-Tang

    2014-01-01

    Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients’ exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, αβ filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD) was used to filter the noise of patients’ attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study. PMID:24714057

  12. Hydration during intense exercise training.

    PubMed

    Maughan, R J; Meyer, N L

    2013-01-01

    Hydration status has profound effects on both physical and mental performance, and sports performance is thus critically affected. Both overhydration and underhydration - if sufficiently severe - will impair performance and pose a risk to health. Athletes may begin exercise in a hypohydrated state as a result of incomplete recovery from water loss induced in order to achieve a specific body mass target or due to incomplete recovery from a previous competition or training session. Dehydration will also develop in endurance exercise where fluid intake does not match water loss. The focus has generally been on training rather than on competition, but sweat loss and fluid replacement in training may have important implications. Hypohydration may impair training quality and may also increase stress levels. It is unclear whether this will have negative effects (reduced training quality, impaired immunity) or whether it will promote a greater adaptive response. Hypohydration and the consequent hyperthermia, however, can enhance the effectiveness of a heat acclimation program, resulting in improved endurance performance in warm and temperate environments. Drinking in training may be important in enhancing tolerance of the gut when athletes plan to drink in competition. The distribution of water between body water compartments may also be important in the initiation and promotion of cellular adaptations to the training stimulus. PMID:23899752

  13. 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…

  14. Is high-intensity exercise better than moderate-intensity exercise for weight loss?

    PubMed

    De Feo, P

    2013-11-01

    This viewpoint debates the state-of-the-art research focusing on the optimal intensity of the exercise programs for inducing a sustained weight or fat-mass loss in overweight/obese people. In our demanding society, the most attractive messages in the popular press are those promising the best results in a short time. This might explain the emphasis given by media to those scientific articles that report the efficacy on weight loss of exercise programs by their shorter duration and higher intensity. However, in the literature on overweight or obese people, there is little conclusive evidence for more favorable effects with high-intensity training than with continuous moderate-intensity exercise on body weight or fat mass loss. Since both exercise protocols have been demonstrated as useful to reduce body weight, the decision on the intensity of exercise prescription should be individualized and based on outcomes different from fat or weight loss. In this regard, there are pro and contra arguments for the prescription of high-intensity aerobic exercise in obese people. Among the pro arguments, is the demonstration that, in several studies, high-intensity training appears to induce superior improvements in aerobic fitness. Among the contra arguments to prescribe high-intensity exercise is the demonstration that prescribing a higher-intensity exercise decreases adherence and results in the completion of less exercise. Thus, a successful exercise program should be proposed at a moderate intensity and a low perceived effort because obese subjects who have low self-efficacy, poor mood status, and are not familiar with high-intensity workouts could easily drop out.

  15. Muscle fatigue during high-intensity exercise in children.

    PubMed

    Ratel, Sébastien; Duché, Pascale; Williams, Craig A

    2006-01-01

    Children are able to resist fatigue better than adults during one or several repeated high-intensity exercise bouts. This finding has been reported by measuring mechanical force or power output profiles during sustained isometric maximal contractions or repeated bouts of high-intensity dynamic exercises. The ability of children to better maintain performance during repeated high-intensity exercise bouts could be related to their lower level of fatigue during exercise and/or faster recovery following exercise. This may be explained by muscle characteristics of children, which are quantitatively and qualitatively different to those of adults. Children have less muscle mass than adults and hence, generate lower absolute power during high-intensity exercise. Some researchers also showed that children were equipped better for oxidative than glycolytic pathways during exercise, which would lead to a lower accumulation of muscle by-products. Furthermore, some reports indicated that the lower ability of children to activate their type II muscle fibres would also explain their greater resistance to fatigue during sustained maximal contractions. The lower accumulation of muscle by-products observed in children may be suggestive of a reduced metabolic signal, which induces lower ratings of perceived exertion. Factors such as faster phosphocreatine resynthesis, greater oxidative capacity, better acid-base regulation, faster readjustment of initial cardiorespiratory parameters and higher removal of metabolic by-products in children could also explain their faster recovery following high-intensity exercise.From a clinical point of view, muscle fatigue profiles are different between healthy children and children with muscle and metabolic diseases. Studies of dystrophic muscles in children indicated contradictory findings of changes in contractile properties and the muscle fatigability. Some have found that the muscle of boys with Duchenne muscular dystrophy (DMD) fatigued less

  16. Higher rate of fat oxidation during rowing compared with cycling ergometer exercise across a range of exercise intensities.

    PubMed

    Egan, B; Ashley, D T; Kennedy, E; O'Connor, P L; O'Gorman, D J

    2016-06-01

    The relative contribution of carbohydrate and fat oxidation to energy expenditure during exercise is dependent on variables including exercise intensity, mode, and recruited muscle mass. This study investigated patterns of substrate utilization during two non-weightbearing exercise modalities, namely cycling and rowing. Thirteen young, moderately trained males performed a continuous incremental (3-min stages) exercise test to exhaustion on separate occasions on an electronically braked cycle (CYC) ergometer and an air-braked rowing (ROW) ergometer, respectively. On two further occasions, participants performed a 20-min steady-state exercise bout at ∼50%VO2peak on the respective modalities. Despite similar oxygen consumption, rates of fat oxidation (FATox ) were ∼45% higher during ROW compared with CYC (P < 0.05) across a range of power output increments. The crossover point for substrate utilization occurred at a higher relative exercise intensity for ROW than CYC (57.8 ± 2.1 vs 42.1 ± 3.6%VO2peak , P < 0.05). During steady-state submaximal exercise, the higher FATox during ROW compared with CYC was maintained (P < 0.05), but absolute FATox were 42% (CYC) and 28% (ROW) lower than during incremental exercise. FATox is higher during ROW compared with CYC exercise across a range of exercise intensities matched for energy expenditure, and is likely as a consequence of larger muscle mass recruited during ROW.

  17. Method to obtain absolute impurity density profiles combining charge exchange and beam emission spectroscopy without absolute intensity calibrationa)

    NASA Astrophysics Data System (ADS)

    Kappatou, A.; Jaspers, R. J. E.; Delabie, E.; Marchuk, O.; Biel, W.; Jakobs, M. A.

    2012-10-01

    Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emission rates, without requiring any absolute calibration of the spectra. The technique is demonstrated here with absolute impurity density radial profiles obtained in TEXTOR plasmas, using a high efficiency charge exchange spectrometer with high etendue, that measures the CXRS and BES spectra along the same lines-of-sight, offering an additional advantage for the determination of absolute impurity densities.

  18. The effects of short intensive exercise on plasma free amino acids in standardbred trotters.

    PubMed

    Hackl, S; van den Hoven, R; Zickl, M; Spona, J; Zentek, J

    2009-04-01

    The aim of this study was to investigate the effect of short intense exercise on plasma amino acid concentrations in trotters and to test the repeatability of plasma amino acids concentration in samples obtained on two independent days under field conditions. Plasma amino acid concentrations were analysed in blood samples of 36 standardbred trotters before and after intense exercise over a distance of 2000 m. Sampling was repeated in 20 horses after 35 days. Exercise intensity was estimated from post-exercise lactate levels. Horses were divided in two groups according to a cut-off lactate concentration at 15 mmol/l. The plasma concentrations of alanine, aspartate, glutamate, isoleucine, leucine, lysine and taurine increased and arginine, asparagine, citrulline, glutamine, glycine, histidine, methionine, serine, tryptophan and 3-methylhistidine decreased after exercise. Ornithine, threonine, tyrosine, phenylalanine and valine concentrations remained constant. Higher intensity of exercise significantly decreased tryptophan and increased taurine concentrations. Sampling day had a significant effect on the absolute pre- and post-exercise amino acid concentrations. Exercise had a significant influence on the concentrations of most plasma amino acids in trotters. These changes could reflect shifts between the free amino acid compartments, but there were also some indications for muscle catabolism. The amino acid supply of sporting horses could be of specific significance for maintaining muscle integrity and for the improvement of post-exercise recovery of competition horses. PMID:19320929

  19. Effects of Exercise Intensity on Postexercise Endothelial Function and Oxidative Stress

    PubMed Central

    McClean, Conor; Harris, Ryan A.; Brown, Malcolm; Brown, John C.; Davison, Gareth W.

    2015-01-01

    Purpose. To measure endothelial function and oxidative stress immediately, 90 minutes, and three hours after exercise of varying intensities. Methods. Sixteen apparently healthy men completed three exercise bouts of treadmill running for 30 minutes at 55% V˙O2max (mild); 20 minutes at 75% V˙O2max (moderate); or 5 minutes at 100% V˙O2max (maximal) in random order. Brachial artery flow-mediated dilation (FMD) was assessed with venous blood samples drawn for measurement of endothelin-1 (ET-1), lipid hydroperoxides (LOOHs), and lipid soluble antioxidants. Results. LOOH increased immediately following moderate exercise (P < 0.05). ET-1 was higher immediately after exercise and 3 hours after exercise in the mild trial compared to maximal one (P < 0.05). Transient decreases were detected for ΔFMD/ShearAUC from baseline following maximal exercise, but it normalised at 3 hours after exercise (P < 0.05). Shear rate was higher immediately after exercise in the maximal trial compared to mild exercise (P < 0.05). No changes in baseline diameter, peak diameter, absolute change in diameter, or FMD were observed following any of the exercise trials (P > 0.05). Conclusions. Acute exercise at different intensities elicits varied effects on oxidative stress, shear rate, and ET-1 that do not appear to mediate changes in endothelial function measured by FMD. PMID:26583061

  20. 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)

  1. Are ceramics and bricks reliable absolute geomagnetic intensity carriers?

    NASA Astrophysics Data System (ADS)

    Morales, Juan; Goguitchaichvili, Avto; Aguilar-Reyes, Bertha; Pineda-Duran, Modesto; Camps, Pierre; Carvallo, Claire; Calvo-Rathert, Manuel

    2011-08-01

    A detailed rock-magnetic and archeointensity study was carried out on materials baked by a western Mexican artisan following traditional techniques to produce faithful reproductions of archeological pieces of the Michoacán region (Western Mesoamerica). The field strength at the site (41.0 ± 0.5 μT) was measured with a fluxgate magnetometer and the temperature of the furnace during the baking process was monitored continually by means of a thermocouple placed in the middle of the baking cavity. Rock-magnetic experiments performed on the raw material (clay and paste) and on insitu prepared baked ceramics and bricks included measurement of thermomagnetic curves (susceptibility and strong-field magnetization versus temperature), first-order reversal curves (FORC), anisotropy of magnetic susceptibility (AMS) and anisotropy of thermoremanent magnetization (A-TRM). Magnetite and probably hematite are present in the samples as carriers of the remanence. Hysteresis ratios suggest that the samples fall in the pseudo-single-domain grain size region, which may indicate a mixture of multi-domain and a significant amount of single-domain grains. Ceramic pieces and brick fragments were subjected to the Thellier-Coe archeointensity method and to an alternative paleointensity experiment, with a TRIAXE magnetometer, in order to check whether they are faithful recorders of the local geomagnetic field strength. Mean raw-intensity of sample M1 (pottery) overestimates a 7% the expected site intensity, while those corresponding to the brick samples (LQ1 and LQ2) underestimate it 15%. Brick sample LNQ shows a slightly lower intensity (7%), but agrees with the expected site intensity within the experimental uncertainty. The intensity retrieved from the volcanic fragment also included closely reproduces the expected intensity. After A-TRM and cooling-rate corrections, all mean raw values move closer to the expected intensity. Measurement of temperatures at different parts inside the kiln

  2. High intensity exercise decreases global brain glucose uptake in humans

    PubMed Central

    Kemppainen, Jukka; Aalto, Sargo; Fujimoto, Toshihiko; Kalliokoski, Kari K; Långsjö, Jaakko; Oikonen, Vesa; Rinne, Juha; Nuutila, Pirjo; Knuuti, Juhani

    2005-01-01

    Physiological activation increases glucose uptake locally in the brain. However, it is not known how high intensity exercise affects regional and global brain glucose uptake. The effect of exercise intensity and exercise capacity on brain glucose uptake was directly measured using positron emission tomography (PET) and [18F]fluoro-deoxy-glucose ([18F]FDG). Fourteen healthy, right-handed men were studied after 35 min of bicycle exercise at exercise intensities corresponding to 30, 55 and 75% of V˙O2max on three separate days. [18F]FDG was injected 10 min after the start of the exercise. Thereafter exercise was continued for another 25 min. PET scanning of the brain was conducted after completion of the exercise. Regional glucose metabolic rate (rGMR) decreased in all measured cortical regions as exercise intensity increased. The mean decrease between the highest and lowest exercise intensity was 32% globally in the brain (38.6 ± 4.6 versus 26.1 ± 5.0 μmol (100 g)−1 min−1, P < 0.001). Lactate availability during exercise tended to correlate negatively with the observed brain glucose uptake. In addition, the decrease in glucose uptake in the dorsal part of the anterior cingulate cortex (37% versus 20%, P < 0.05 between 30% and 75% of V˙O2max) was significantly more pronounced in subjects with higher exercise capacity. These results demonstrate that brain glucose uptake decreases with increase in exercise intensity. Therefore substrates other than glucose, most likely lactate, are utilized by the brain in order to compensate the increased energy needed to maintain neuronal activity during high intensity exercise. Moreover, it seems that exercise training could be related to adaptive metabolic changes locally in the frontal cortical regions. PMID:16037089

  3. 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.

  4. 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

  5. Estimation of Exercise Intensity in “Exercise and Physical Activity Reference for Health Promotion”

    NASA Astrophysics Data System (ADS)

    Ohkubo, Tomoyuki; Kurihara, Yosuke; Kobayashi, Kazuyuki; Watanabe, Kajiro

    To maintain or promote the health condition of elderly citizens is quite important for Japan. Given the circumstances, the Ministry of Health, Labour and Welfare has established the standards for the activities and exercises for promoting the health, and quantitatively determined the exercise intensity on 107 items of activities. This exercise intensity, however, requires recording the type and the duration of the activity to be calculated. In this paper, the exercise intensities are estimated using 3D accelerometer for 25 daily activities. As the result, the exercise intensities were estimated to be within the root mean square error of 0.83 METs for all 25 activities.

  6. Salivary Cortisol Responses and Perceived Exertion during High Intensity and Low Intensity Bouts of Resistance Exercise

    PubMed Central

    McGuigan, Michael R.; Egan, Alison D.; Foster, Carl

    2004-01-01

    The purpose of this study was to measure the salivary cortisol response to different intensities of resistance exercise. In addition, we wanted to determine the reliability of the session rating of perceived exertion (RPE) scale to monitor resistance exercise intensity. Subjects (8 men, 9 women) completed 2 trials of acute resistance training bouts in a counterbalanced design. The high intensity resistance exercise protocol consisted of six, ten-repetition sets using 75% of one repetition maximum (RM) on a Smith machine squat and bench press exercise (12 sets total). The low intensity resistance exercise protocol consisted of three, ten-repetition sets at 30% of 1RM of the same exercises as the high intensity protocol. Both exercise bouts were performed with 2 minutes of rest between each exercise and sessions were repeated to test reliability of the measures. The order of the exercise bouts was randomized with least 72 hours between each session. Saliva samples were obtained immediately before, immediately after and 30 mins following each resistance exercise bout. RPE measures were obtained using Borg’s CR-10 scale following each set. Also, the session RPE for the entire exercise session was obtained 30 minutes following completion of the session. There was a significant 97% increase in the level of salivary cortisol immediately following the high intensity exercise session (P<0.05). There was also a significant difference in salivary cortisol of 145% between the low intensity and high intensity exercise session immediately post-exercise (P<0.05). The low intensity exercise did not result in any significant changes in cortisol levels. There was also a significant difference between the session RPE values for the different intensity levels (high intensity 7.1 vs. low intensity 1.9) (P<0.05). The intraclass correlation coefficient for the session RPE measure was 0.95. It was concluded that the session RPE method is a valid and reliable method of quantifying

  7. Exercise training in COPD: What is it about intensity?

    PubMed

    Morris, Norman R; Walsh, James; Adams, Lewis; Alision, Jennifer

    2016-10-01

    Most of the current guidelines for pulmonary rehabilitation recommend higher, over lower, intensity exercise training for COPD. Typically, we consider intensity of exercise training to be a key component of any exercise training programme. Whilst studies of young individuals have demonstrated that higher exercise training intensity results in greater improvements in exercise capacity, the evidence for older patients is not so clear cut. In COPD, there is limited evidence regarding the optimal intensity of exercise training. Using both physiological (peak exercise capacity) and patient-centred (e.g. quality of life) outcomes, it remains inconclusive if higher intensity exercise training bestows any greater benefit than low-intensity exercise. If we examine the data from interval training studies, which used both high- and low-intensity interval and continuous exercise, we are able to generate more data for comparison. Unfortunately, these data are challenging to interpret due to heterogeneity in how interval training was prescribed. However, when we normalize the interval training data for training volume and examine the change in peak cycling power, there is a relationship between training intensity and increase in peak power (Wpeak , r = 0.68, P < 0.05). Hence, whilst there is an inconclusive amount of evidence to support this intervention based on studies that only examined high- versus low-intensity continuous exercise, the additional data from interval training studies would suggest that higher intensity may be superior in terms of increases in Wpeak . Future studies should focus on establishing a threshold and an optimal training intensity for COPD. PMID:27623321

  8. High-intensity aerobic interval exercise in chronic heart failure.

    PubMed

    Meyer, Philippe; Gayda, Mathieu; Juneau, Martin; Nigam, Anil

    2013-06-01

    Aerobic exercise training is strongly recommended in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF) to improve symptoms and quality of life. Moderate-intensity aerobic continuous exercise (MICE) is the best established training modality in HF patients. For about a decade, however, another training modality, high-intensity aerobic interval exercise (HIIE), has aroused considerable interest in cardiac rehabilitation. Originally used by athletes, HIIE consists of repeated bouts of high-intensity exercise interspersed with recovery periods. The rationale for its use is to increase exercise time spent in high-intensity zones, thereby increasing the training stimulus. Several studies have demonstrated that HIIE is more effective than MICE, notably for improving exercise capacity in patients with HF. The aim of the present review is to describe the general principles of HIIE prescription, the acute physiological effects, the longer-term training effects, and finally the future perspectives of HIIE in patients with HF.

  9. High-intensity interval training attenuates the exercise-induced increase in plasma IL-6 in response to acute exercise.

    PubMed

    Croft, Louise; Bartlett, Jonathan D; MacLaren, Don P M; Reilly, Thomas; Evans, Louise; Mattey, Derek L; Nixon, Nicola B; Drust, Barry; Morton, James P

    2009-12-01

    This aims of this study were to investigate the effects of carbohydrate availability during endurance training on the plasma interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-alpha response to a subsequent acute bout of high-intensity interval exercise. Three groups of recreationally active males performed 6 weeks of high-intensity interval running. Groups 1 (LOW+GLU) and 2 (LOW+PLA) trained twice per day, 2 days per week, and consumed a 6.4% glucose or placebo solution, respectively, before every second training session and at regular intervals throughout exercise. Group 3 (NORM) trained once per day, 4 days per week, and consumed no beverage during training. Each group performed 50 min of high-intensity interval running at the same absolute workloads before and after training. Muscle glycogen utilization in the gastrocnemius muscle during acute exercise was reduced (p < 0.05) in all groups following training, although this was not affected by training condition. Plasma IL-6 concentration increased (p < 0.05) after acute exercise in all groups before and after training. Furthermore, the magnitude of increase was reduced (p < 0.05) following training. This training-induced attenuation in plasma IL-6 increase was similar among groups. Plasma IL-8 concentration increased (p < 0.05) after acute exercise in all groups, although the magnitude of increase was not affected (p > 0.05) by training. Acute exercise did not increase (p > 0.05) plasma TNF-alpha when undertaken before or after training. Data demonstrate that the exercise-induced increase in plasma IL-6 concentration in response to customary exercise is attenuated by previous exercise training, and that this attenuation appears to occur independent of carbohydrate availability during training.

  10. Recognizing the intensity of strength training exercises with wearable sensors.

    PubMed

    Pernek, Igor; Kurillo, Gregorij; Stiglic, Gregor; Bajcsy, Ruzena

    2015-12-01

    In this paper we propose a system based on a network of wearable accelerometers and an off-the-shelf smartphone to recognize the intensity of stationary activities, such as strength training exercises. The system uses a hierarchical algorithm, consisting of two layers of Support Vector Machines (SVMs), to first recognize the type of exercise being performed, followed by recognition of exercise intensity. The first layer uses a single SVM to recognize the type of the performed exercise. Based on the recognized type a corresponding intensity prediction SVM is selected on the second layer, specializing in intensity prediction for the recognized type of exercise. We evaluate the system for a set of upper-body exercises using different weight loads. Additionally, we compare the most important features for exercise and intensity recognition tasks and investigate how different sliding window combinations, sensor configurations and number of training subjects impact the algorithm performance. We perform all of the experiments for two different types of features to evaluate the feasibility of implementation on resource constrained hardware. The results show the algorithm is able to recognize exercise types with approximately 85% accuracy and 6% intensity prediction error. Furthermore, due to similar performance using different types of features, the algorithm offers potential for implementation on resource constrained hardware.

  11. 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.

  12. Cardiovascular responses to exercise as functions of absolute and relative work load

    NASA Technical Reports Server (NTRS)

    Lewis, S. F.; Taylor, W. F.; Graham, R. M.; Pettinger, W. A.; Schutte, J. E.; Blomqvist, C. G.

    1983-01-01

    The roles of absolute and relative oxygen uptake (VO2 and percent of muscle group specific VO2-max) as determinants of the cardiovascular and ventilatory responses to exercise over a wide range of active muscle mass are investigated. Experiments were conducted using four types of dynamic exercise: one-arm curl, one-arm cranking, and one and two-leg cycling at four different relative work loads (25, 50, 75, and 100 percent of VO2-max) for the corresponding muscle group. Results show that VO2 during maximal one-arm curl, one-arm cranking, and one-leg cycling averaged 20, 50, and 75 percent, respectively, of that for maximal two-leg cycling. Cardiac output was determined to be linearly related to VO2 with a similar slope and intercept for each type of exercise, and the heart rate at a given percent VO2-max was higher with larger active muscle mass. It is concluded that the cardiovascular responses to exercise was determined to a large extent by the active muscle mass and the absolute oxygen uptake, with the principal feature appearing to be the tight linkage between systematic oxygen transport and utilization.

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

    PubMed Central

    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. PMID:27490493

  14. 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…

  15. The beneficial role of intensive exercise on Parkinson disease progression.

    PubMed

    Frazzitta, Giuseppe; Balbi, Pietro; Maestri, Roberto; Bertotti, Gabriella; Boveri, Natalia; Pezzoli, Gianni

    2013-06-01

    In the last decade, a considerable number of articles has shown that exercise is effective in improving motor performance in Parkinson disease. In particular, recent studies have focused on the efficacy of intensive exercise in achieving optimal results in the rehabilitation of patients with Parkinson disease. The effects of intensive exercise in promoting cell proliferation and neuronal differentiation in animal models are reported in a large cohort of studies, and these neuroplastic effects are probably related to increased expression of a variety of neurotrophic factors. The authors outline the relation between intensive exercises and neuroplastic activity on animal models of Parkinson disease and discuss the clinical results of different intensive strategies on motor performance and disease progression in patients with Parkinson disease.

  16. Space Station Live: High-Intensity Exercise in Space

    NASA Video Gallery

    NASA Public Affairs Officer Lori Meggs talks with SPRINT Principal Investigator Lori Ploutz-Snyder to learn more about this high-intensity exercise research taking place aboard the International Sp...

  17. 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. PMID:24276299

  18. 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. PMID:21756130

  19. Glassy carbon as an absolute intensity calibration standard for small-angle scattering.

    SciTech Connect

    Zhang, F.; Ilavsky, J.; Long, G.; Allen, A.; Quintana, J.; Jemian, P.; NIST

    2010-05-01

    Absolute calibration of small-angle scattering (SAS) intensity data (measured in terms of the differential scattering cross section per unit sample volume per unit solid angle) is essential for many important aspects of quantitative SAS analysis, such as obtaining the number density, volume fraction, and specific surface area of the scatterers. It also enables scattering data from different instruments (light, X-ray, or neutron scattering) to be combined, and it can even be useful to detect the existence of artifacts in the experimental data. Different primary or secondary calibration methods are available. In the latter case, absolute intensity calibration requires a stable artifact with the necessary scattering profile. Glassy carbon has sometimes been selected as this intensity calibration standard. Here we review the spatial homogeneity and temporal stability of one type of commercially available glassy carbon that is being used as an intensity calibration standard at a number of SAS facilities. We demonstrate that glassy carbon is sufficiently homogeneous and stable during routine use to be relied upon as a suitable standard for absolute intensity calibration of SAS data.

  20. Revised Pioneer 10 absolute electron intensities in the inner Jovian magnetosphere

    NASA Technical Reports Server (NTRS)

    Baker, D. N.; Van Allen, J. A.

    1977-01-01

    Improved techniques for the analysis of Pioneer 10 Jupiter encounter data are used to obtain significantly more reliable values for energetic electron (Ee less than 21 MeV) intensities within the inner magnetosphere. The revised absolute intensities of electrons in the energy range 0.06-21 MeV are less than previous estimates by factors as great as 10 for L not exceeding 6. Previously published intensities at greater radial distances for Ee less than 21 MeV and at all radial distances for Ee greater than 21 MeV are not affected by the revisions.

  1. High-Intensity Interval Exercise and Postprandial Triacylglycerol.

    PubMed

    Burns, Stephen F; Miyashita, Masashi; Stensel, David J

    2015-07-01

    This review examined if high-intensity interval exercise (HIIE) reduces postprandial triacylglycerol (TAG) levels. Fifteen studies were identified, in which the effect of interval exercise conducted at an intensity of >65% of maximal oxygen uptake was evaluated on postprandial TAG levels. Analysis was divided between studies that included supramaximal exercise and those that included submaximal interval exercise. Ten studies examined the effect of a single session of low-volume HIIE including supramaximal sprints on postprandial TAG. Seven of these studies noted reductions in the postprandial total TAG area under the curve the morning after exercise of between ~10 and 21% compared with rest, but three investigations found no significant difference in TAG levels. Variations in the HIIE protocol used, inter-individual variation or insufficient time post-exercise for an increase in lipoprotein lipase activity are proposed reasons for the divergent results among studies. Five studies examined the effect of high-volume submaximal interval exercise on postprandial TAG. Four of these studies were characterised by high exercise energy expenditure and effectively attenuated total postprandial TAG levels by ~15-30%, but one study with a lower energy expenditure found no effect on TAG. The evidence suggests that supramaximal HIIE can induce large reductions in postprandial TAG levels but findings are inconsistent. Submaximal interval exercise offers no TAG metabolic or time advantage over continuous aerobic exercise but could be appealing in nature to some individuals. Future research should examine if submaximal interval exercise can reduce TAG levels in line with more realistic and achievable exercise durations of 30 min per day.

  2. Assessment of the Exercise Intensity of Short Stick Exercises in Elderly Individuals

    PubMed Central

    Kurasawa, Shigeki; Yokoi, Katsushi; Miyai, Nobuyuki; Takemura, Shigeki; Miyashita, Kazuhisa

    2015-01-01

    The present study was to obtain basic data for applying the short stick exercises to frail elderly individuals. A total of 20 individuals aged ≥60 years (10 men, and 10 women) with independence in activities of daily living participated in a short stick exercise program. During the exercise program, the time required and the number of times the short stick was dropped were investigated. The exercise intensity was also evaluated based on expired gas and heart rate measurements. The mean exercise intensity of the short stick exercises was 1.9 ± 0.3 metabolic equivalents (METs), equivalent to talking while standing or walking indoors. Compared to the early elderly (those aged 60 to 74 years), the late elderly (those aged ≥75 years) had a significantly higher number of stick drops and significantly lower increase in heart rate from resting to the warming-up exercise. The short stick exercises had a low exercise intensity and can be applicable to exercise interventions of the frail elderly individuals. However, in the case of the late elderly, the high frequency of short stick drops and the change in heart rate during warming up must be considered. PMID:25734017

  3. Effects of high-intensity interval exercise versus continuous moderate-intensity exercise on postprandial glycemic control assessed by continuous glucose monitoring in obese adults.

    PubMed

    Little, Jonathan P; Jung, Mary E; Wright, Amy E; Wright, Wendi; Manders, Ralph J F

    2014-07-01

    The purpose of this study was to examine the impact of acute high-intensity interval training (HIIT) compared with continuous moderate-intensity (CMI) exercise on postprandial hyperglycemia in overweight or obese adults. Ten inactive, overweight or obese adults (41 ± 11 yrs, BMI = 36 ± 7 kg/m(2)) performed an acute bout of HIIT (10 × 1 min at approximately 90% peak heart rate (HRpeak) with 1-min recovery periods) or matched work CMI (30 min at approximately 65% HRpeak) in a randomized, counterbalanced fashion. Exercise was performed 2 h after breakfast, and glucose control was assessed by continuous glucose monitoring under standardized dietary conditions over 24 h. Postprandial glucose (PPG) responses to lunch, dinner, and the following day's breakfast were analyzed and compared with a no-exercise control day. Exercise did not affect the PPG responses to lunch, but performing both HIIT and CMI in the morning significantly reduced the PPG incremental area under the curve (AUC) following dinner when compared with control (HIIT = 110 ± 35, CMI = 125 ± 34, control = 162 ± 46 mmol/L × 2 h, p < 0.05). The PPG AUC (HIIT = 125 ± 53, CMI = 186 ± 55, control = 194 ± 96 mmol/L × 2 h) and the PPG spike (HIIT = Δ2.1 ± 0.9, CMI = Δ3.0 ± 0.9, control = Δ3.0 ± 1.5 mmol/l) following breakfast on the following day were significantly lower following HIIT compared with both CMI and control (p < 0.05). Absolute AUC and absolute glucose spikes were not different between HIIT, CMI, or control for any meal (p > 0.05 for all). We conclude that a single session of HIIT has greater and more lasting effects on reducing incremental PPG when compared with CMI.

  4. Absolute intensity measurement of the 4-0 vibration-rotation band of carbon monoxide

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.; Valero, F. P. J.

    1976-01-01

    The absolute intensity of the 4-0 vibration band of CO is measured in spectra obtained using a 25-m base-path multiple-traversal absorption cell and a 5-m scanning spectrometer. The intensities of individual vibration-rotation lines in this band are determined from measurements of their equivalent widths, and absolute values for the rotationless transition moment and the vibration-rotation interaction factor are derived from the measured line strengths. The experimentally obtained vibration-rotation function is compared with a theoretical curve; agreement between theory and experiment is found to be good for the P-branch but poor for the R-branch. It is noted that numerical solutions to the radial Schroedinger equation lead to vibration-rotation function values that are in good agreement with the experiment.

  5. Absolute intensity calibration of the 32-channel heterodyne radiometer on experimental advanced superconducting tokamak

    SciTech Connect

    Liu, X.; Zhao, H. L.; Liu, Y. Li, E. Z.; Han, X.; Ti, A.; Hu, L. Q.; Zhang, X. D.; Domier, C. W.; Luhmann, N. C.

    2014-09-15

    This paper presents the results of the in situ absolute intensity calibration for the 32-channel heterodyne radiometer on the experimental advanced superconducting tokamak. The hot/cold load method is adopted, and the coherent averaging technique is employed to improve the signal to noise ratio. Measured spectra and electron temperature profiles are compared with those from an independent calibrated Michelson interferometer, and there is a relatively good agreement between the results from the two different systems.

  6. Intensive exercise training suppresses testosterone during bed rest

    NASA Technical Reports Server (NTRS)

    Wade, C. E.; Stanford, K. I.; Stein, T. P.; Greenleaf, J. E.

    2005-01-01

    Spaceflight and prolonged bed rest (BR) alter plasma hormone levels inconsistently. This may be due, in part, to prescription of heavy exercise as a countermeasure for ameliorating the adverse effects of disuse. The initial project was to assess exercise programs to maintain aerobic performance and leg strength during BR. The present study evaluates the effect of BR and the performance of the prescribed exercise countermeasures on plasma steroid levels. In a 30-day BR study of male subjects, the efficacy of isotonic (ITE, n = 7) or isokinetic exercise (IKE, n = 7) training was evaluated in contrast to no exercise (n = 5). These exercise countermeasures protected aerobic performance and leg strength successfully. BR alone (no-exercise group) did not change steroidogenesis, as assessed by the plasma concentrations of cortisol, progesterone, aldosterone, and free (FT) and total testosterone (TT). In the exercise groups, both FT and TT were decreased (P < 0.05): FT during IKE from 24 +/- 1.7 to 18 +/- 2.0 pg/ml and during ITE from 21 +/- 1.5 to 18 +/- 1 pg/ml, and TT during IKE from 748 +/- 68 to 534 +/- 46 ng/dl and during ITE from 565 +/- 36 to 496 +/- 38 ng/dl. The effect of intensive exercise countermeasures on plasma testosterone was not associated with indexes of overtraining. The reduction in plasma testosterone associated with both the IKE and ITE countermeasures during BR supports our hypothesis that intensive exercise countermeasures may, in part, contribute to changes in plasma steroid concentrations during spaceflight.

  7. 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

  8. Ascending aortic blood flow dynamics following intense exercise.

    PubMed

    Kilgour, R D; Sellers, W R

    1990-10-01

    The purpose of this study was to compare and contrast aortic blood flow kinetics during recovery from intense aerobic (maximal oxygen uptake test) and anaerobic (Wingate anaerobic power test) exercise. Fifteen healthy male subjects (VO2max = 56.1 +/- 5.8 mk/kg/min) participated in this study. Beat-to-beat peak aortic blood flow velocity (pkV) and acceleration (pkA) measurements were obtained by placing a 3.0 MHz continuous-wave ultrasonic transducer on the suprasternal notch at rest and during recovery (immediately post-exercise, 2.5 min, and 5.0 min) following the two exercise conditions. Peak velocity and acceleration significantly increased (p less than 0.01) from rest to immediately post-exercise and remained elevated throughout the 5-min recovery period. No differences were observed between the aerobic and anaerobic tests. Stroke distance significantly declined (p less than 0.01) immediately following exercise and progressively rose during the 5-min recovery period. The results indicate that: 1) aortic blood flow kinetics remained elevated during short-term recovery, and 2) intense aerobic and anaerobic exercise exhibit similar post-exercise aortic blood flow kinetics. PMID:2262232

  9. Transcranial magnetic stimulation intensity affects exercise-induced changes in corticomotoneuronal excitability and inhibition and voluntary activation.

    PubMed

    Bachasson, D; Temesi, J; Gruet, M; Yokoyama, K; Rupp, T; Millet, G Y; Verges, Samuel

    2016-02-01

    Transcranial magnetic stimulation (TMS) of the motor cortex during voluntary contractions elicits electrophysiological and mechanical responses in the target muscle. The effect of different TMS intensities on exercise-induced changes in TMS-elicited variables is unknown, impairing data interpretation. This study aimed to investigate TMS intensity effects on maximal voluntary activation (VATMS), motor-evoked potentials (MEPs), and silent periods (SPs) in the quadriceps muscles before, during, and after exhaustive isometric exercise. Eleven subjects performed sets of ten 5-s submaximal isometric quadriceps contractions at 40% of maximal voluntary contraction (MVC) strength until task failure. Three different TMS intensities (I100, I75, I50) eliciting MEPs of 53 ± 6%, 38 ± 5% and 25 ± 3% of maximal compound action potential (Mmax) at 20% MVC were used. MEPs and SPs were assessed at both absolute (40% baseline MVC) and relative (50%, 75%, and 100% MVC) force levels. VATMS was assessed with I100 and I75. When measured at absolute force level, MEP/Mmax increased during exercise at I50, decreased at I100 and remained unchanged at I75. No TMS intensity effect was observed at relative force levels. At both absolute and relative force levels, SPs increased at I100 and remained stable at I75 and I50. VATMS assessed at I75 tended to be lower than at I100. TMS intensity affects exercise-induced changes in MEP/Mmax (only when measured at absolute force level), SPs, and VATMS. These results indicate a single TMS intensity assessing maximal voluntary activation and exercise-induced changes in corticomotoneuronal excitability/inhibition may be inappropriate.

  10. Absolute intensity and polarization of rotational Raman scattering from N2, O2, and CO2

    NASA Technical Reports Server (NTRS)

    Penney, C. M.; St.peters, R. L.; Lapp, M.

    1973-01-01

    An experimental examination of the absolute intensity, polarization, and relative line intensities of rotational Raman scattering (RRS) from N2, O2, and CO2 is reported. The absolute scattering intensity for N2 is characterized by its differential cross section for backscattering of incident light at 647.1 nm, which is calculated from basic measured values. The ratio of the corresponding cross section for O2 to that for N2 is 2.50 plus or minus 5 percent. The intensity recent for N2, O2, and CO2 are shown to compare favorably to values calculated from recent measurements of the depolarization of Rayleigh scattering plus RRS. Measured depolarizations of various RRS lines agree to within a few percent with the theoretical value of 3/4. Detailed error analyses are presented for intensity and depolarization measurements. Finally, extensive RRS spectra at nominal gas temperatures of 23 C, 75 C, and 125 C are presented and shown to compare favorably to theoretical predictions.

  11. Intensity evaluation using a femtosecond pulse laser for absolute distance measurement.

    PubMed

    Wu, Hanzhong; Zhang, Fumin; Li, Jianshuang; Cao, Shiying; Meng, Xiangsong; Qu, Xinghua

    2015-06-10

    In this paper, we propose a method of intensity evaluation based on different pulse models using a femtosecond pulse laser, which enables long-range absolute distance measurement with nanometer precision and large non-ambiguity range. The pulse cross-correlation is analyzed based on different pulse models, including Gaussian, Sech(2), and Lorenz. The DC intensity and the amplitude of the cross-correlation patterns are also demonstrated theoretically. In the experiments, we develop a new combined system and perform the distance measurements on an underground granite rail system. The DC intensity and amplitude of the interference fringes are measured and show a good agreement with the theory, and the distance to be determined can be up to 25 m using intensity evaluation, within 64 nm deviation compared with a He-Ne incremental interferometer, and corresponds to a relative precision of 2.7×10(-9). PMID:26192864

  12. Intensity evaluation using a femtosecond pulse laser for absolute distance measurement.

    PubMed

    Wu, Hanzhong; Zhang, Fumin; Li, Jianshuang; Cao, Shiying; Meng, Xiangsong; Qu, Xinghua

    2015-06-10

    In this paper, we propose a method of intensity evaluation based on different pulse models using a femtosecond pulse laser, which enables long-range absolute distance measurement with nanometer precision and large non-ambiguity range. The pulse cross-correlation is analyzed based on different pulse models, including Gaussian, Sech(2), and Lorenz. The DC intensity and the amplitude of the cross-correlation patterns are also demonstrated theoretically. In the experiments, we develop a new combined system and perform the distance measurements on an underground granite rail system. The DC intensity and amplitude of the interference fringes are measured and show a good agreement with the theory, and the distance to be determined can be up to 25 m using intensity evaluation, within 64 nm deviation compared with a He-Ne incremental interferometer, and corresponds to a relative precision of 2.7×10(-9).

  13. High angular resolution absolute intensity of the solar continuum from 1400 to 1790 A.

    NASA Technical Reports Server (NTRS)

    Brueckner, G. E.; Moe, O. K.

    1972-01-01

    Absolute intensities of the solar UV continuum from 1400 to 1790 A have been measured from rocket spectra taken on August 13, 1970. The spectra had an angular resolution of 2 arc sec by 1 arc min, and the pointing accuracy of the instrument was plus or minus 2 arc sec. This permits us to study the center-to-limb variation of the intensity with a spatial resolution of 2 arc sec. Four positions on the solar disk have been studied corresponding to values of cos theta = 0.12, 0.22, 0.28 and 0.72, where theta is the heliocentric position angle. The measurements give higher values for the intensity than recent photoelectric measurement, but are in good agreement with the intensities of Widing et al.

  14. Measurements of absolute line intensities in carbon dioxide bands near 5.2 microns

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Benner, D. C.; Devi, V. M.

    1985-01-01

    A nonlinear least-squares spectral fitting procedure has been used to derive experimental absolute intensities for over 300 unblended lines belonging to twelve CO2 bands in the 5.2-micron region. The spectral data were recorded at 0.01/cm resolution and room temperature with the Fourier transform spectrometer in the McMath solar telescope complex at the National Solar Observatory on Kitt Peak and have a signal-to-rms noise ratio of 2000-4000. A natural sample of carbon dioxide was used as the sample gas. For each band, the measured line intensities have been analyzed to derive the vibrational band intensity and coefficients of the F factor. The results are compared to the values used to calculate the intensities in the 1982 Air Force Geophysics Laboratory line parameters compilation.

  15. Acute Exercise and Motor Memory Consolidation: The Role of Exercise Intensity

    PubMed Central

    Geertsen, Svend S.; Christiansen, Lasse; Ritz, Christian; Roig, Marc

    2016-01-01

    A single bout of high intensity aerobic exercise (~90% VO2peak) was previously demonstrated to amplify off-line gains in skill level during the consolidation phase of procedural memory. High intensity exercise is not always a viable option for many patient groups or in a rehabilitation setting where low to moderate intensities may be more suitable. The aim of this study was to investigate the role of intensity in mediating the effects of acute cardiovascular exercise on motor skill learning. We investigated the effects of different exercise intensities on the retention (performance score) of a visuomotor accuracy tracking task. Thirty six healthy male subjects were randomly assigned to one of three groups that performed either a single bout of aerobic exercise at 20 min post motor skill learning at 45% (EX45), 90% (EX90) maximal power output (Wmax) or rested (CON). Randomization was stratified to ensure that the groups were matched for relative peak oxygen consumption (ml O2/min/kg) and baseline score in the tracking task. Retention tests were carried out at 1 (R1) and 7 days (R7) post motor skill learning. At R1, changes in performance scores were greater for EX90 compared to CON (p<0.001) and EX45 (p = 0.011). The EX45 and EX90 groups demonstrated a greater change in performance score at R7 compared to the CON group (p = 0.003 and p<0.001, respectively). The change in performance score for EX90 at R7 was also greater than EX45 (p = 0.049). We suggest that exercise intensity plays an important role in modulating the effects that a single bout of cardiovascular exercise has on the consolidation phase following motor skill learning. There appears to be a dose-response relationship in favour of higher intensity exercise in order to augment off-line effects and strengthen procedural memory. PMID:27454423

  16. Acute Exercise and Motor Memory Consolidation: The Role of Exercise Intensity.

    PubMed

    Thomas, Richard; Johnsen, Line K; Geertsen, Svend S; Christiansen, Lasse; Ritz, Christian; Roig, Marc; Lundbye-Jensen, Jesper

    2016-01-01

    A single bout of high intensity aerobic exercise (~90% VO2peak) was previously demonstrated to amplify off-line gains in skill level during the consolidation phase of procedural memory. High intensity exercise is not always a viable option for many patient groups or in a rehabilitation setting where low to moderate intensities may be more suitable. The aim of this study was to investigate the role of intensity in mediating the effects of acute cardiovascular exercise on motor skill learning. We investigated the effects of different exercise intensities on the retention (performance score) of a visuomotor accuracy tracking task. Thirty six healthy male subjects were randomly assigned to one of three groups that performed either a single bout of aerobic exercise at 20 min post motor skill learning at 45% (EX45), 90% (EX90) maximal power output (Wmax) or rested (CON). Randomization was stratified to ensure that the groups were matched for relative peak oxygen consumption (ml O2/min/kg) and baseline score in the tracking task. Retention tests were carried out at 1 (R1) and 7 days (R7) post motor skill learning. At R1, changes in performance scores were greater for EX90 compared to CON (p<0.001) and EX45 (p = 0.011). The EX45 and EX90 groups demonstrated a greater change in performance score at R7 compared to the CON group (p = 0.003 and p<0.001, respectively). The change in performance score for EX90 at R7 was also greater than EX45 (p = 0.049). We suggest that exercise intensity plays an important role in modulating the effects that a single bout of cardiovascular exercise has on the consolidation phase following motor skill learning. There appears to be a dose-response relationship in favour of higher intensity exercise in order to augment off-line effects and strengthen procedural memory. PMID:27454423

  17. Acute Exercise and Motor Memory Consolidation: The Role of Exercise Intensity.

    PubMed

    Thomas, Richard; Johnsen, Line K; Geertsen, Svend S; Christiansen, Lasse; Ritz, Christian; Roig, Marc; Lundbye-Jensen, Jesper

    2016-01-01

    A single bout of high intensity aerobic exercise (~90% VO2peak) was previously demonstrated to amplify off-line gains in skill level during the consolidation phase of procedural memory. High intensity exercise is not always a viable option for many patient groups or in a rehabilitation setting where low to moderate intensities may be more suitable. The aim of this study was to investigate the role of intensity in mediating the effects of acute cardiovascular exercise on motor skill learning. We investigated the effects of different exercise intensities on the retention (performance score) of a visuomotor accuracy tracking task. Thirty six healthy male subjects were randomly assigned to one of three groups that performed either a single bout of aerobic exercise at 20 min post motor skill learning at 45% (EX45), 90% (EX90) maximal power output (Wmax) or rested (CON). Randomization was stratified to ensure that the groups were matched for relative peak oxygen consumption (ml O2/min/kg) and baseline score in the tracking task. Retention tests were carried out at 1 (R1) and 7 days (R7) post motor skill learning. At R1, changes in performance scores were greater for EX90 compared to CON (p<0.001) and EX45 (p = 0.011). The EX45 and EX90 groups demonstrated a greater change in performance score at R7 compared to the CON group (p = 0.003 and p<0.001, respectively). The change in performance score for EX90 at R7 was also greater than EX45 (p = 0.049). We suggest that exercise intensity plays an important role in modulating the effects that a single bout of cardiovascular exercise has on the consolidation phase following motor skill learning. There appears to be a dose-response relationship in favour of higher intensity exercise in order to augment off-line effects and strengthen procedural memory.

  18. 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.

  19. Similar Responses of Circulating MicroRNAs to Acute High-Intensity Interval Exercise and Vigorous-Intensity Continuous Exercise.

    PubMed

    Cui, Shu F; Wang, Cheng; Yin, Xin; Tian, Dong; Lu, Qiu J; Zhang, Chen Y; Chen, Xi; Ma, Ji Z

    2016-01-01

    High-intensity interval exercise (HIIE) has been reported to be more beneficial for physical adaptation than low-to-moderate exercise intensity. Recently, it is becoming increasingly evident that circulating miRNAs (c-miRNAs) may distinguish between specific stress signals imposed by variations in the duration, modality, and type of exercise. The aim of this study is to investigate whether or not HIIE is superior to vigorous-intensity continuous exercise (VICE), which is contributing to develop effective fitness assessment. Twenty-six young males were enrolled, and plasma samples were collected prior to exercise and immediately after HIIE or distance-matched VICE. The miRNA level profiles in HIIE were initially determined using TaqMan Low Density Array (TLDA). And the differentially miRNAs levels were validated by stem-loop quantitative reverse-transcription PCR (RT-qPCR). Furthermore, these selective c-miRNAs were measured for VICE. Our results showed that some muscle-related miRNAs levels in the plasma, such as miR-1, miR-133a, miR-133b, and miR-206 significantly increased following HIIE or VICE compared to those at rest (P < 0.05), and there was only a significant reduction in miR-1 level for HIIE compared to VICE (P < 0.05), while no significant differences were observed for other muscle-related miRNAs between both exercises (P > 0.05). In addition, some tissue-related or unknown original miRNA levels, such as miR-485-5p, miR-509-5p, miR-517a, miR-518f, miR-520f, miR-522, miR-553, and miR-888, also significantly increased (P < 0.05) in both exercises compared to rest. However, no significant differences were found between both exercises (P > 0.05). Overall, endurance exercise assessed in this study both led to significant increases in selective c-miRNAs of comparable magnitude, suggesting that both types of endurance exercise have general stress processes. Accordingly, the similar responses to both acute exercises likely indicate both exercises can be used

  20. Similar Responses of Circulating MicroRNAs to Acute High-Intensity Interval Exercise and Vigorous-Intensity Continuous Exercise

    PubMed Central

    Cui, Shu F.; Wang, Cheng; Yin, Xin; Tian, Dong; Lu, Qiu J.; Zhang, Chen Y.; Chen, Xi; Ma, Ji Z.

    2016-01-01

    High-intensity interval exercise (HIIE) has been reported to be more beneficial for physical adaptation than low-to-moderate exercise intensity. Recently, it is becoming increasingly evident that circulating miRNAs (c-miRNAs) may distinguish between specific stress signals imposed by variations in the duration, modality, and type of exercise. The aim of this study is to investigate whether or not HIIE is superior to vigorous-intensity continuous exercise (VICE), which is contributing to develop effective fitness assessment. Twenty-six young males were enrolled, and plasma samples were collected prior to exercise and immediately after HIIE or distance-matched VICE. The miRNA level profiles in HIIE were initially determined using TaqMan Low Density Array (TLDA). And the differentially miRNAs levels were validated by stem-loop quantitative reverse-transcription PCR (RT-qPCR). Furthermore, these selective c-miRNAs were measured for VICE. Our results showed that some muscle-related miRNAs levels in the plasma, such as miR-1, miR-133a, miR-133b, and miR-206 significantly increased following HIIE or VICE compared to those at rest (P < 0.05), and there was only a significant reduction in miR-1 level for HIIE compared to VICE (P < 0.05), while no significant differences were observed for other muscle-related miRNAs between both exercises (P > 0.05). In addition, some tissue-related or unknown original miRNA levels, such as miR-485-5p, miR-509-5p, miR-517a, miR-518f, miR-520f, miR-522, miR-553, and miR-888, also significantly increased (P < 0.05) in both exercises compared to rest. However, no significant differences were found between both exercises (P > 0.05). Overall, endurance exercise assessed in this study both led to significant increases in selective c-miRNAs of comparable magnitude, suggesting that both types of endurance exercise have general stress processes. Accordingly, the similar responses to both acute exercises likely indicate both exercises can be used

  1. Similar Responses of Circulating MicroRNAs to Acute High-Intensity Interval Exercise and Vigorous-Intensity Continuous Exercise.

    PubMed

    Cui, Shu F; Wang, Cheng; Yin, Xin; Tian, Dong; Lu, Qiu J; Zhang, Chen Y; Chen, Xi; Ma, Ji Z

    2016-01-01

    High-intensity interval exercise (HIIE) has been reported to be more beneficial for physical adaptation than low-to-moderate exercise intensity. Recently, it is becoming increasingly evident that circulating miRNAs (c-miRNAs) may distinguish between specific stress signals imposed by variations in the duration, modality, and type of exercise. The aim of this study is to investigate whether or not HIIE is superior to vigorous-intensity continuous exercise (VICE), which is contributing to develop effective fitness assessment. Twenty-six young males were enrolled, and plasma samples were collected prior to exercise and immediately after HIIE or distance-matched VICE. The miRNA level profiles in HIIE were initially determined using TaqMan Low Density Array (TLDA). And the differentially miRNAs levels were validated by stem-loop quantitative reverse-transcription PCR (RT-qPCR). Furthermore, these selective c-miRNAs were measured for VICE. Our results showed that some muscle-related miRNAs levels in the plasma, such as miR-1, miR-133a, miR-133b, and miR-206 significantly increased following HIIE or VICE compared to those at rest (P < 0.05), and there was only a significant reduction in miR-1 level for HIIE compared to VICE (P < 0.05), while no significant differences were observed for other muscle-related miRNAs between both exercises (P > 0.05). In addition, some tissue-related or unknown original miRNA levels, such as miR-485-5p, miR-509-5p, miR-517a, miR-518f, miR-520f, miR-522, miR-553, and miR-888, also significantly increased (P < 0.05) in both exercises compared to rest. However, no significant differences were found between both exercises (P > 0.05). Overall, endurance exercise assessed in this study both led to significant increases in selective c-miRNAs of comparable magnitude, suggesting that both types of endurance exercise have general stress processes. Accordingly, the similar responses to both acute exercises likely indicate both exercises can be used

  2. Beta-alanine supplementation in high-intensity exercise.

    PubMed

    Harris, Roger C; Sale, Craig

    2012-01-01

    Glycolysis involves the oxidation of two neutral hydroxyl groups on each glycosyl (or glucosyl) unit metabolised, yielding two carboxylic acid groups. During low-intensity exercise these, along with the remainder of the carbon skeleton, are further oxidised to CO(2) and water. But during high-intensity exercise a major portion (and where blood flow is impaired, then most) is accumulated as lactate anions and H(+). The accumulation of H(+) has deleterious effects on muscle function, ultimately impairing force production and contributing to fatigue. Regulation of intracellular pH is achieved over time by export of H(+) out of the muscle, although physicochemical buffers in the muscle provide the first line of defence against H(+) accumulation. In order to be effective during high-intensity exercise, buffers need to be present in high concentrations in muscle and have pK(a)s within the intracellular exercise pH transit range. Carnosine (β-alanyl-L-histidine) is ideal for this role given that it occurs in millimolar concentrations within the skeletal muscle and has a pK(a) of 6.83. Carnosine is a cytoplasmic dipeptide formed by bonding histidine and β-alanine in a reaction catalysed by carnosine synthase, although it is the availability of β-alanine, obtained in small amounts from hepatic synthesis and potentially in greater amounts from the diet that is limiting to synthesis. Increasing muscle carnosine through increased dietary intake of β-alanine will increase the intracellular buffering capacity, which in turn might be expected to increase high-intensity exercise capacity and performance where this is pH limited. In this study we review the role of muscle carnosine as an H(+) buffer, the regulation of muscle carnosine by β-alanine, and the available evidence relating to the effects of β-alanine supplementation on muscle carnosine synthesis and the subsequent effects of this on high-intensity exercise capacity and performance.

  3. Absolute intensity measurements of CO2 bands in the 2395-2680/cm region

    NASA Technical Reports Server (NTRS)

    Malathy Devi, V.; Benner, D. C.; Rinsland, C. P.

    1984-01-01

    Absolute intensities for over 800 transitions belonging to twelve bands of (C-12)(O-16)2, (O-16)(C-12)(O-18), (O-16)(C-12)(O-17), and (O-16)(C-13)(O-18) molecules in the 2395-2680/cm spectral region have been derived using a nonlinear least-squares spectral fitting procedure. The data used in the analysis were recorded at room temperature and low pressure with the 0.01/cm resolution Fourier transform spectrometer in the McMath solar telescope complex at the National Solar Observatory. The measured intensities obtained for each band have been analyzed to derive the vibrational band intensity and F-factor coefficients. The results are compared with other published values.

  4. High-intensity intermittent exercise and fat loss.

    PubMed

    Boutcher, Stephen H

    2011-01-01

    The effect of regular aerobic exercise on body fat is negligible; however, other forms of exercise may have a greater impact on body composition. For example, emerging research examining high-intensity intermittent exercise (HIIE) indicates that it may be more effective at reducing subcutaneous and abdominal body fat than other types of exercise. The mechanisms underlying the fat reduction induced by HIIE, however, are undetermined. Regular HIIE has been shown to significantly increase both aerobic and anaerobic fitness. HIIE also significantly lowers insulin resistance and results in a number of skeletal muscle adaptations that result in enhanced skeletal muscle fat oxidation and improved glucose tolerance. This review summarizes the results of HIIE studies on fat loss, fitness, insulin resistance, and skeletal muscle. Possible mechanisms underlying HIIE-induced fat loss and implications for the use of HIIE in the treatment and prevention of obesity are also discussed.

  5. 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

  6. Responses of growth hormone aggregates to different intermittent exercise intensities.

    PubMed

    Rubin, Martyn R; Kraemer, William J; Kraemer, Robert R; Durand, Robert J; Acevedo, Edmund O; Johnson, Lisa G; Castracane, V D; Scheett, Timothy P; French, Duncan N; Volek, Jeff S

    2003-04-01

    The purpose of this study was to determine the impact of high-intensity intermittent exercise on the presence of circulating growth hormone (GH) aggregates measured using two different assay techniques. Six male subjects with endurance training background participated in this study under both exercise and no-exercise control conditions. After resting blood sampling, subjects completed an intermittent treadmill exercise protocol at four speeds predicted to elicit a specific VO(2):60% VO(2max) for 10 min, 75% for 10 min, 90% for 5 min, and 100% for 2 min. After each exercise intensity was completed treadmill speed was reduced to a walk (3.5-4 min) for blood sampling. Sampling continued every 15 min for 1 h into recovery. All samples were then measured for GH concentrations using Nichols immunoradiometric assay (IRMA) and Diagnostic Systems Laboratory's immunofunctional assay (IFA). A second set of samples was chemically reduced using reduced glutathione (GSH; 10 mM for 18 h at room temperature) to break disulfide bonds between possible oligomeric GH complexes, and subsequently assayed using the same GH assays. With the IRMA, GH was significantly elevated ( P<0.05) after the 75% workload and remained elevated through 30 min post-exercise. After adding GSH to the sample, the IRMA indicated significant increases in GH as early as the 60% exercise intensity and remained elevated through 45 min into recovery. At 75%, the GSH assay run was significantly higher than the non-GSH assay run. With the IFA, GH was significantly elevated at 60% in the non-GSH condition, whereas the GSH assay run indicated significant elevations at 75%. Both GSH and non-GSH conditions remained elevated through 30 min into recovery. These data indicate that the addition of GSH to serum samples prior to assay via an IRMA may break existing disulfide bonds between aggregated GH molecules, thus altering the apparent assay signal to reveal greater total GH in the sample.

  7. Infrared mapping of ultrasound fields generated by medical transducers: Feasibility of determining absolute intensity levels

    PubMed Central

    Khokhlova, Vera A.; Shmeleva, Svetlana M.; Gavrilov, Leonid R.; Martin, Eleanor; Sadhoo, Neelaksh; Shaw, Adam

    2013-01-01

    Considerable progress has been achieved in the use of infrared (IR) techniques for qualitative mapping of acoustic fields of high intensity focused ultrasound (HIFU) transducers. The authors have previously developed and demonstrated a method based on IR camera measurement of the temperature rise induced in an absorber less than 2 mm thick by ultrasonic bursts of less than 1 s duration. The goal of this paper was to make the method more quantitative and estimate the absolute intensity distributions by determining an overall calibration factor for the absorber and camera system. The implemented approach involved correlating the temperature rise measured in an absorber using an IR camera with the pressure distribution measured in water using a hydrophone. The measurements were conducted for two HIFU transducers and a flat physiotherapy transducer of 1 MHz frequency. Corresponding correction factors between the free field intensity and temperature were obtained and allowed the conversion of temperature images to intensity distributions. The system described here was able to map in good detail focused and unfocused ultrasound fields with sub-millimeter structure and with local time average intensity from below 0.1 W/cm2 to at least 50 W/cm2. Significantly higher intensities could be measured simply by reducing the duty cycle. PMID:23927199

  8. Skin temperature as a thermal controller of exercise intensity.

    PubMed

    Schlader, Zachary J; Simmons, Shona E; Stannard, Stephen R; Mündel, Toby

    2011-08-01

    This study examined the role of skin temperature on self-selected exercise intensity (i.e., power output). Eight well-trained, male cyclists completed two 60 min self-paced cycling bouts during which they completed as much work as possible. Using a liquid-perfused suit, skin temperature (T (Sk)) was changed during the two trials such that T (Sk) either started hot and was cooled (H to C) or started cold and was heated (C to H) throughout exercise. Pre-exercise core temperatures (T (C)) and heart rates (HR) were similar between trials, while T (Sk), thermal comfort and thermal sensation were higher in H to C. The change in T (Sk) was similar in magnitude during the two trials. Work completed was greatest in C to H, which was attributed to a higher initial power output. T (C) was similar between trials. HR was similar until 35 min had elapsed, after which it became lower in H to C. The perception of effort increased similarly between the two trials, while thermal comfort and thermal sensation generally reflected the changes observed in T (Sk). These results indicate that upon exercise commencement T (Sk) and the accompanying thermal perceptions are important inputs in the initial selection of exercise intensity.

  9. 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.

  10. 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

  11. Absolute line intensities in CO2 bands near 4.8 microns

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Benner, D. C.; Devi, V. M.

    1986-01-01

    Absolute intensities for 726 unblended lines in 20 bands of C-12(O-16)2, C-13(O-16)2, O-16C-12O-18, and O-16C-12O-17 in the 4.8-micron spectral region have been determined using a natural sample of ultrahigh-purity CO2. Spectral data were recorded at low pressure (less than 10 torr) and room temperature with the Fourier transform spectrometer in the McMath solar telescope complex on Kitt Peak. Derived vibrational band intensities and coefficients of the F factor for each band were compared to values of the 1982 Air Force Geophysics Laboratory line parameters compilation. The present work fills out the CO2 lines in the 5-micron band systems. Lines in the strongest of these measured bands are being used to infer atmospheric pressure from high-resolution stratospheric spectra recorded during the Spacelab 3 Atmospheric Trace Molecule Spectroscopy experiment.

  12. 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.

  13. 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…

  14. Absolute intensities of CO2 lines in the 3140-3410/cm spectral region

    NASA Technical Reports Server (NTRS)

    Benner, D. Chris; Devi, V. Malathy; Ferry-Leeper, Penelope S.; Rinsland, Curtis P.

    1988-01-01

    Absolute intensities for 430 transitions belonging to eleven rotation-vibration bands of (C-12)(O-16)2, (C-13)(O-16)2, and (O-16)(C-18)(O-18) in the 3140-3410/cm spectral region have been determined by analyzing spectra recorded at 0.01/cm resolution with the Fourier transform spectrometer in the McMath solar telescope complex at the National Solar Observatory on Kitt Peak. The data were recorded at room temperature and low pressures (less than 10 torr) using a natural sample of carbon dioxide. Intensities were derived using a nonlinear least-squares spectral fitting procedure, and the values obtained for each band have been analyzed to determine the vibrational band intensity and nonrigid rotor coefficients. An alternative mathematical formulation is shown in the case of bands for which the Coriolis effect is large and the Q-branch line intensities were not determinable either because they were severely blended or absent from the spectra. Comparison are made between the results obtained in this study and other published values.

  15. Absolute intensities of CO(2) lines in the 3140-3410-cm(-1) spectral region.

    PubMed

    Benner, D C; Devi, V M; Rinsland, C P; Ferry-Leeper, P S

    1988-04-15

    Absolute intensities for 430 transitions belonging to eleven rotation-vibration bands of (12)C(16)O(2),(13)C(16)O(2) and(16)O(12)C(18)O in the 3140-3410-cm(-1) spectral region have been determined by analyzing spectra recorded at 0.01-cm(-1) resolution with the Fourier transform spectrometer in the McMath solar telescope complex at the National Solar Observatory on Kitt Peak. The data were recorded at room temperature and low pressures (<10 Torr) using a natural sample of carbon dioxide. Intensities were derived using a nonlinear least-squares spectral fitting procedure, and the values obtained for each band have been analyzed to determine the vibrational band intensity and nonrigid rotor coefficients. An alternative mathematical formulation is shown in the case of bands for which the Coriolis effect is large and the Q-branch line intensities were not determinate either because they were severely blended or absent from the spectra. Comparisons are made between the results obtained in this study and other published values.

  16. Intensive Exercise Training During Bed Rest Attenuates Deconditioning

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    1997-01-01

    Intensive exercise training during bed rest attenuates deconditioning. Med. Sci. Sports Exerc., Vol. 29, No. 2, pp. 207-215, 1997. A 30-d 6 deg head-down bed rest project was conducted to evaluate variable high-intensity, short-duration, isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent resistive isokinetic exercise (IKE) training regimens designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (adaptive) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Major findings are summarized in this paper. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volumes, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (f) attenuated the decrease in peak VO2 by 50%, (g) attenuated loss of red cell volume by 40% but had no effect on loss of plasma volume, (b) induced positive body water balance, (i) had no adverse effect on quality of sleep or concentration, and 0) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regimens and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

  17. Effect of Different Exercise Intensities on the Myotendinous Junction Plasticity.

    PubMed

    Curzi, Davide; Sartini, Stefano; Guescini, Michele; Lattanzi, Davide; Di Palma, Michael; Ambrogini, Patrizia; Savelli, David; Stocchi, Vilberto; Cuppini, Riccardo; Falcieri, Elisabetta

    2016-01-01

    Myotendinous junctions (MTJs) are anatomical regions specialized in transmission of contractile strength from muscle to tendon and, for this reason, a common site where acute injuries occur during sport activities. In this work we investigated the influence of exercise intensity on MTJ plasticity, as well as on the expression of insulin-like growth factor 1 (IGF-1) and transforming growth factor beta (TGF-β) and their receptors in muscle and tendon. Three groups of rats were analyzed: control (CTRL), slow-runner (RUN-S) and fast-runner (RUN-F) trained using a treadmill. Ultrastructural and morphometric analyses of distal MTJs from extensor digitorum longus muscles have been performed. Contractile strength and hypertrophy were investigated by using in vivo tension recordings and muscle cross-sectional area (CSA) analysis, respectively. mRNA levels of PGC-1α, vinculin, IGF-1Ea and TGF-β have been quantified in muscle belly, while IGF-1Ea, TGF-β and their receptors in tendon. Morphometry revealed an increased MTJ complexity and interaction surface between tissues in trained rats according to training intensity. CSA analysis excluded hypertrophy among groups, while muscle strength was found significantly enhanced in exercised rats in comparison to controls. In muscle tissue, we highlighted an increased mRNA expression of PGC-1α and vinculin in both trained conditions and of TGF-β in RUN-F. In tendon, we mainly noted an enhancement of TGF-β mRNA expression only in RUN-F group and a raise of Betaglycan tendon receptor mRNA levels proportional to exercise intensity. In conclusion, MTJ plasticity appears to be related to exercise intensity and molecular analysis suggests a major role played by TGF-β. PMID:27337061

  18. Effect of Different Exercise Intensities on the Myotendinous Junction Plasticity

    PubMed Central

    Guescini, Michele; Lattanzi, Davide; Di Palma, Michael; Ambrogini, Patrizia; Savelli, David; Stocchi, Vilberto; Cuppini, Riccardo; Falcieri, Elisabetta

    2016-01-01

    Myotendinous junctions (MTJs) are anatomical regions specialized in transmission of contractile strength from muscle to tendon and, for this reason, a common site where acute injuries occur during sport activities. In this work we investigated the influence of exercise intensity on MTJ plasticity, as well as on the expression of insulin-like growth factor 1 (IGF-1) and transforming growth factor beta (TGF-β) and their receptors in muscle and tendon. Three groups of rats were analyzed: control (CTRL), slow-runner (RUN-S) and fast-runner (RUN-F) trained using a treadmill. Ultrastructural and morphometric analyses of distal MTJs from extensor digitorum longus muscles have been performed. Contractile strength and hypertrophy were investigated by using in vivo tension recordings and muscle cross-sectional area (CSA) analysis, respectively. mRNA levels of PGC-1α, vinculin, IGF-1Ea and TGF-β have been quantified in muscle belly, while IGF-1Ea, TGF-β and their receptors in tendon. Morphometry revealed an increased MTJ complexity and interaction surface between tissues in trained rats according to training intensity. CSA analysis excluded hypertrophy among groups, while muscle strength was found significantly enhanced in exercised rats in comparison to controls. In muscle tissue, we highlighted an increased mRNA expression of PGC-1α and vinculin in both trained conditions and of TGF-β in RUN-F. In tendon, we mainly noted an enhancement of TGF-β mRNA expression only in RUN-F group and a raise of Betaglycan tendon receptor mRNA levels proportional to exercise intensity. In conclusion, MTJ plasticity appears to be related to exercise intensity and molecular analysis suggests a major role played by TGF-β. PMID:27337061

  19. Relative and absolute intensity calibrations of a modern broadband echelle spectrometer

    NASA Astrophysics Data System (ADS)

    Bibinov, N.; Halfmann, H.; Awakowicz, P.; Wiesemann, K.

    2007-05-01

    We report on relative and absolute intensity calibrations of a modern broadband echelle spectrometer (type ESA 3000® trademark of LLA Instruments GmbH, Berlin) for use in the diagnostics of low-temperature plasma. This type of device measures simultaneously complete emission spectra in the spectral range from 200 to 800 nm with a spectral resolution of several picometres by using more than 90 spectral orders, causing a strongly structured efficiency function. The assumptions and approximations entering the calibration procedure under these conditions are discussed in section 3. For coping with the strongly structured efficiency function a continuum light source is needed, which covers the entire spectral range. Furthermore, the variation of its intensity must be low enough to ensure that neither statistical errors perturb the calibration in regions with low photon flux and/or low efficiency, nor local memory overflow in regions with high photon flux or high efficiency. In our case this requires that during calibration over the whole spectral range of the spectrometer the counts per pixel in one measurement vary at highest by a factor 10 to 12. Usual broadband light sources do not meet this latter requirement. We, therefore, use an uncalibrated 'composite' source, an adjustable combination of a standard tungsten strip lamp and a deuterium lamp, and calibrate the spectrometer in a two-step process against the tungsten strip lamp and well-known rovibrational intensity distributions in the emission spectra of NO and N2. We adjust the composite source in a way to produce a perturbation-free first approximation of an (uncalibrated) efficiency function, which is then corrected and thus calibrated by comparison with the (secondary) standards mentioned above. For absolute calibration we use the tungsten strip lamp. The uncertainty attained in this way for the relative calibration depends on the wavelength and varies between 5% and 10%. For the absolute calibration we

  20. Intensive exercise training during bed rest attenuates deconditioning.

    PubMed

    Greenleaf, J E

    1997-02-01

    A 30-d 6 degrees head-down bed rest project was conducted to evaluate variable high-intensity, short-duration, isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent resistive isokinetic exercise (IKE) training regimens designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (adaptive) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Major findings are summarized in this paper. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volumes (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (f) attenuated the decrease in peak VO2 by 50%, (g) attenuated loss of red cell volume by 40% but had no effect on loss of plasma volume, (h) induced positive body water balance, (i) had no adverse effect on quality of sleep or concentration, and (j) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regimens and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

  1. Core stabilization exercises enhance lactate clearance following high-intensity exercise.

    PubMed

    Navalta, James W; Hrncir, Stephen P

    2007-11-01

    Dynamic activities such as running, cycling, and swimming have been shown to effectively reduce lactate in the postexercise period. It is unknown whether core stabilization exercises performed following an intense bout would exhibit a similar effect. Therefore, this study was designed to assess the extent of the lactate response with core stabilization exercises following high-intensity anaerobic exercise. Subjects (N = 12) reported twice for testing, and on both occasions baseline lactate was obtained after 5 minutes of seated rest. Subjects then performed a 30-second Wingate anaerobic cycle test, immediately followed by a blood lactate sample. In the 5-minute postexercise period, subjects either rested quietly or performed core stabilization exercises. A final blood lactate sample was obtained following the 5-minute intervention period. Analysis revealed a significant interaction (p = 0.05). Lactate values were similar at rest (core = 1.4 +/- 0.1, rest = 1.7 +/- 0.2 mmol x L(-1)) and immediately after exercise (core = 4.9 +/- 0.6, rest = 5.4 +/- 0.4 mmol x L(-1)). However, core stabilization exercises performed during the 5-minute postexercise period reduced lactate values when compared to rest (5.9 +/- 0.6 vs. 7.6 +/- 0.8 mmol x L(-1)). The results of this study show that performing core stabilization exercises during a recovery period significantly reduces lactate values. The reduction in lactate may be due to removal via increased blood flow or enhanced uptake into the core musculature. Incorporation of core stability exercises into a cool-down period following muscular work may result in benefits to both lactate clearance as well as enhanced postural control.

  2. Absolute continuum intensity diagnostics of a novel large coaxial gridded hollow cathode argon plasma

    NASA Astrophysics Data System (ADS)

    Gao, Ruilin; Yuan, Chengxun; Li, Hui; Jia, Jieshu; Zhou, Zhong-Xiang; Wu, Jian; Wang, Ying; Wang, Xiaoou

    2016-08-01

    This paper reports a novel coaxial gridded hollow discharge during operation at low pressure (20 Pa-80 Pa) in an argon atmosphere. A homogeneous hollow discharge was observed under different conditions, and the excitation mechanism and the discharge parameters for the hollow cathode plasma were examined at length. An optical emission spectrometry (OES) method, with a special focus on absolute continuum intensity method, was employed to measure the plasma parameters. The Langmuir probe measurement (LPM) was used to verify the OES results. Both provided electron density values (ne) in the order of 1016 m-3 for different plasma settings. Taken together, the results show that the OES method is an effective approach to diagnosing the similar plasma, especially when the LPM is hardly operated.

  3. Increased sensations of intensity of breathlessness impairs maintenance of intense intermittent exercise.

    PubMed

    Tong, Tom K; Fu, Frank H; Chow, Bik C; Quach, Binh; Lu, Kui

    2003-01-01

    To identify the reserve of an individual's tolerance of the sensation of breathlessness and metabolic stress in maintaining intense intermittent exercise at exhaustion under conditions of normal breathing, the contribution of the effect of modest inspiratory load on these two responses to the change in the exercise sustainability (Ex(sus)) were examined. Seven men repeatedly performed 12 s exercise at 160% maximal aerobic power output followed by passive recovery for 18 s under normal and ventilatory muscle loaded (VML) breathing conditions until exhaustion. In the VML trial, ventilatory muscle work at exhaustion was double that of the normal control. The control Ex(sus) was reduced [mean (SEM)] [31.7 (6.6)%] while the slope of the time course for the rating of the perceived magnitude of breathing effort (RPMBE/Time), which reflected the intensity of breathlessness, was increased [164.8 (32.2)%] from control and the RPMBE at exhaustion was higher than corresponding control value [144.4 (21.8)%]. Moreover, increases in plasma ammonia and uric acid concentrations, which indicated metabolic stress, were increased [168.1 (28.0)% and 251.7 (57.4)%, respectively], with no change in total oxygen uptake from control when the control exercise was repeated with an identical duration of VML exercise. It was found that the reduction in Ex(sus) in the VML trial was correlated to the increase in their sensations of the intensity of breathlessness (RPMBE/Time: r=0.81; RPMBE at exhaustion: r=0.97, P<0.05). The reduction in Ex(sus), however, was not correlated to the increase in metabolite concentrations. These findings implied that there was no substantial reserve of tolerance of the sensation of breathlessness relative to that of metabolic stress in subjects maintaining intense intermittent exercise at exhaustion under normal conditions of breathing.

  4. 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.

  5. Spectroscopic determination of electrical conductivity in an MHD duct from absolute intensity measurements

    NASA Technical Reports Server (NTRS)

    Wang, S. Y.; Smith, M.

    1977-01-01

    Measurements of the electrical conductivity in the NASA Lewis cesium seeded, H2-O2 MHD duct have been previously reported. In order to corroborate the above measurements and to analyze the possibility of nonuniform seed injection as a cause of the deviations, a spectroscopic investigation of the plasma conductivity has been undertaken. Transverse profiles of the absolute integrated intensity were measured from the optically thin lines of CSI-.5664 microns and .5636 microns. Radial profiles of emission coefficient were obtained from the measured transverse profiles of intensity by Abel inversion. Radial profiles of electrical conductivity were then obtained under two different assumptions. In the first, the Cs seed fraction is assumed uniform and equal to the measured flow rate at the time when the temperature and conductivity were obtained. In the second method, the local temperature and pressure are taken to be those given by a one-dimensional channel calculation including heat transfer and friction. In this case profiles of conductivity and seed fractions are obtained. The results of the two methods are compared to the previously measured conductivity.

  6. Low-intensity treadmill exercise promotes rat dorsal wound healing.

    PubMed

    Zhou, Wu; Liu, Guo-hui; Yang, Shu-hua; Mi, Bo-bin; Ye, Shu-nan

    2016-02-01

    In order to investigate the promoting effect of low-intensity treadmill exercise on rat dorsal wound healing and the mechanism, 20 Sprague-Dawley rats were randomly divided into two groups: exercise group (Ex) and non-exercise group (non-ex). The rats in Ex group were given treadmill exercise for one month, and those in non-ex group raised on the same conditions without treadmill exercise. Both groups received dorsal wound operation with free access to food and water. By two-week continuous observation and recording of the wound area, the healing rate was analyzed. The blood sample was collected at day 14 post-operation via cardiac puncture for determination of the number of endothelial progenitor cells (EPCs) by flow cytometry, and the concentrations of relevant cytokines such as basic fibroblast growth factor (bFGF), endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) were measured by ELISA. The skin tissue around the wound was dissected to observe the vascular density under the microscope after HE staining, to detect the mRNA level of VEGFR2 and angiopoietin-1 (Ang-1) receptor using RT-qPCR, and protein expression of a-smooth muscle actin (αSMA) and type III collagen (ColIII) using Western blotting. It was found that the wound area in Ex group was smaller at the same time point than in non-ex group. The number of circulating EPCs was greater and the concentrations of vasoactive factors such as VEGF, eNOS and bFGF were higher in Ex group than in non-ex group. HE staining displayed a higher vessel density in Ex group than in non-ex group. Moreover, the mRNA expression of VEGFR2 and Ang-1 detected in the wound tissue in Ex group was higher than in non-ex group. Meanwhile, the protein expression of αSMA and ColIII was more abundant in Ex group than in non-ex group. Conclusively, the above results demonstrate Ex rats had a higher wound healing rate, suggesting low-intensity treadmill exercise accelerates wound healing. The present

  7. Effects of Different Intensities of Endurance Exercise in Morning and Evening on the Lipid Metabolism Response

    PubMed Central

    Kim, Hyeon-Ki; Ando, Karina; Tabata, Hiroki; Konishi, Masayuki; Takahashi, Masaki; Nishimaki, Mio; Xiang, Mi; Sakamoto, Shizuo

    2016-01-01

    To study the effects of different exercise intensity performed at different exercise times on lipid metabolism response during prolonged exercise. Nine young men performed endurance exercise at different exercise intensities (60%VO2max or Fatmax) in the morning (9 am to 10 am) or evening (5 pm to 6 pm); blood samples were collected before exercise and immediately and one and two hours after exercise completion. Expired gas was analyzed from the start of exercise until two hours after exercise completion. There were no significant changes in catecholamine (adrenaline and noradrenaline) and free fatty acid levels between morning and evening trials for each endurance exercise intensity. However, the morning and evening trials both exhibited significantly higher lipid oxidation at Fatmax than that at 60%VO2max. These results suggest that exercise at Fatmax offers greater lipid oxidation than that at 60%VO2max, regardless of exercise timing. Key points It is important to consider exercise intensity when evaluating lipid oxidation. Few studies have investigated the effects of the intensity of exercise on lipid oxidation in the morning and evening. Fatmax exhibited greater total lipid oxidation compared to that of 60%VO2max when energy expenditure was equated, but time of day did not affect lipid oxidation in prolonged exercise. PMID:27803625

  8. Exploring the dose-response relationship between resistance exercise intensity and cognitive function.

    PubMed

    Chang, Yu-Kai; Etnier, Jennifer L

    2009-10-01

    The purpose of this study was to explore the dose-response relationship between resistance exercise intensity and cognitive performance. Sixty-eight participants were randomly assigned into control, 40%, 70%, or 100% of 10-repetition maximal resistance exercise groups. Participants were tested on Day 1 (baseline) and on Day 2 (measures were taken relative to performance of the treatment). Heart rate, ratings of perceived exertion, self-reported arousal, and affect were assessed on both days. Cognitive performance was assessed on Day 1 and before and following treatment on Day 2. Results from regression analyses indicated that there is a significant linear effect of exercise intensity on information processing speed, and a significant quadratic trend for exercise intensity on executive function. Thus, there is a dose-response relationship between the intensity of resistance exercise and cognitive performance such that high-intensity exercise benefits speed of processing, but moderate intensity exercise is most beneficial for executive function. PMID:20016113

  9. The time-frame of acute resistance exercise effects on football skill performance: the impact of exercise intensity.

    PubMed

    Draganidis, Dimitrios; Chatzinikolaou, Athanasios; Jamurtas, Athanasios Z; Carlos Barbero, Jose; Tsoukas, Dimitrios; Theodorou, Apostolos Spyridon; Margonis, Konstantinos; Michailidis, Yannis; Avloniti, Alexandra; Theodorou, Anastasios; Kambas, Antonis; Fatouros, Ioannis

    2013-01-01

    The purpose of this study was to determine the recovery rate of football skill performance following resistance exercise of moderate or high intensity. Ten elite football players participated in three different trials: control, low-intensity resistance exercise (4 sets, 8-10 repetitions/set, 65-70% 1 repetition maximum [1RM]) and high-intensity resistance exercise (4 sets, 4-6 repetitions/set, 85-90% 1RM) in a counterbalanced manner. In each experimental condition, participants were evaluated pre, post, and at 24, 48, 72 h post exercise time points. Football skill performance was assessed through the Loughborough Soccer Passing Test, long passing, dribbling, shooting and heading. Delayed onset muscle soreness, knee joint range of motion, and muscle strength (1RM) in squat were considered as muscle damage markers. Blood samples analysed for creatine kinase activity, C-reactive protein, and leukocyte count. Passing and shooting performance declined (P < 0.05) post-exercise following resistance exercise. Strength declined post-exercise following high-intensity resistance exercise. Both trials induced only a mild muscle damage and inflammatory response in an intensity-dependent manner. These results indicate that football skill performance is minimally affected by acute resistance exercise independent of intensity suggesting that elite players may be able to participate in a football practice or match after only 24 h following a strength training session. PMID:23301779

  10. The time-frame of acute resistance exercise effects on football skill performance: the impact of exercise intensity.

    PubMed

    Draganidis, Dimitrios; Chatzinikolaou, Athanasios; Jamurtas, Athanasios Z; Carlos Barbero, Jose; Tsoukas, Dimitrios; Theodorou, Apostolos Spyridon; Margonis, Konstantinos; Michailidis, Yannis; Avloniti, Alexandra; Theodorou, Anastasios; Kambas, Antonis; Fatouros, Ioannis

    2013-01-01

    The purpose of this study was to determine the recovery rate of football skill performance following resistance exercise of moderate or high intensity. Ten elite football players participated in three different trials: control, low-intensity resistance exercise (4 sets, 8-10 repetitions/set, 65-70% 1 repetition maximum [1RM]) and high-intensity resistance exercise (4 sets, 4-6 repetitions/set, 85-90% 1RM) in a counterbalanced manner. In each experimental condition, participants were evaluated pre, post, and at 24, 48, 72 h post exercise time points. Football skill performance was assessed through the Loughborough Soccer Passing Test, long passing, dribbling, shooting and heading. Delayed onset muscle soreness, knee joint range of motion, and muscle strength (1RM) in squat were considered as muscle damage markers. Blood samples analysed for creatine kinase activity, C-reactive protein, and leukocyte count. Passing and shooting performance declined (P < 0.05) post-exercise following resistance exercise. Strength declined post-exercise following high-intensity resistance exercise. Both trials induced only a mild muscle damage and inflammatory response in an intensity-dependent manner. These results indicate that football skill performance is minimally affected by acute resistance exercise independent of intensity suggesting that elite players may be able to participate in a football practice or match after only 24 h following a strength training session.

  11. Spectroscopic determination of electrical conductivity in an MHD duct from absolute intensity measurements

    NASA Technical Reports Server (NTRS)

    Wang, S. Y.; Smith, J. M.

    1977-01-01

    Measurements of the electrical conductivity in the NASA Lewis cesium seeded, H2-O2 MHD duct made by applying a voltage across the channel from one end electrode to the other, measuring the current, and using the inner electrodes as probes to monitor the voltage distribution along the channel were found to be in good agreement with theory except at low combustion pressures and/or high ratios of seed/oxygen mass flows. To corroborate these measurements and to analyze the possibility of nonuniform seed injection as a cause of the above deviations, a spectroscopic investigation of the plasma conductivity was undertaken. Radial profiles of emission coefficient were obtained from measured transverse profiles of the absolute integrated intensity by Abel inversion. Radial profiles of electrical conductivity were then obtained under two different assumptions. In the first the Cs seed fraction is assumed uniform and equal to the measured flow rate at the time when the temperature and conductivity were obtained. In the second method the local temperature and pressure are taken to be those given by a one-dimensional channel calculation including heat transfer and friction. The results of the two methods are compared to the previously measured conductivity.

  12. Seasonal absolute acoustic intensity, atmospheric forcing and currents in a tropical coral reef system

    NASA Astrophysics Data System (ADS)

    de Jesús Salas Pérez, José; Salas-Monreal, David; Monreal-Gómez, María Adela; Riveron-Enzastiga, Mayra Lorena; Llasat, Carme

    2012-03-01

    The seasonal patterns of marine circulation and biovolume were obtained from time-series measurements carried out in the "Parque Nacional Sistema Arrecifal Veracruzano" (PNSAV), located in the western continental shelf of the Gulf of Mexico, from June 2008 to September 2009. Two mechanisms were depicted as the responsible for the current pattern observed in the PNSAV and not only one as suggested in large-scale studies. The first mechanism is the wind generated currents. This mechanism by itself is responsible for up to 78% of total variation of the seasonal circulation in the PNSAV as estimated with the first mode of the EOF's (Empirical Orthogonal Functions), which was correlated (Normalized Lagged Correlation) with the north-south wind component. Therefore, the wind and the first mode were highly correlated for most of the year (r > 0.7). The second mode was attributed to the low frequency current, associated to the meso-scale circulation of the Gulf of Mexico, owing to the cyclonic eddy of the Campeche Bay. Both mechanisms were mostly observed throughout the year. Nevertheless, the cyclonic eddy of the Campeche Bay (meso-scale) was the first responsible for the current fluctuations observed during the summer of 2008 and 2009. The absolute acoustic intensity (plankton biovolumes) was highly correlated to currents, showing high spatial variability, attributed to advection produced by the meso-scale circulation and to river discharges, but also by eddy diffusion produced by atmospheric and coastal water fronts.

  13. Absolute intensity calibration of two-channel prototype ITER vacuum ultraviolet spectrometer with a collimating mirror.

    NASA Astrophysics Data System (ADS)

    Seon, Changrae; Hong, Joohwan; Cheon, Munseong; Pak, Sunil; Lee, Hyeongon; Biel, Wolfgang; Barnsley, Robin

    2012-10-01

    To optimize the design of ITER vacuum ultraviolet (VUV) spectrometer, a two-channel prototype spectrometer was implemented with No. 3 (14.4 nm -- 31.8 nm) and No. 4 (29.0 nm -- 60.0 nm) among the five channels. The prototype is composed of a toroidal mirror, and two toroidal diffraction gratings and two different detectors of the back-illuminated CCD and the micro-channel plate (MCP). To verify each optical component, the absolute intensity calibration was performed using the calibrated hollow cathode lamp. Inverse sensitivities of each spectrometer were derived by dividing the incident photon numbers with the measured detector counts. The measured sensitivity values were consistent with the sensitivities calculated from the grating and the detector efficiencies. Consequently the calibration curves of the two-channel VUV spectrometer were provided, and the mirror reflectivity and the detector efficiency could be confirmed experimentally. For the application of the calibrated spectrometer, measurements of impurity lines in KSTAR plasmas were performed, and the line integrated emissivity was derived from the calibration curve during impurity injection experiments.

  14. Intense exercise increases protein oxidation in spleen and liver of mice.

    PubMed

    Kobayashi, Yukiko; Nakatsuji, Aki; Aoi, Wataru; Wada, Sayori; Kuwahata, Masashi; Kido, Yasuhiro

    2014-01-01

    Studies have indicated that sports anemia is mainly associated with intravascular hemolysis induced by exercise. We hypothesized that such exercise-induced hemolysis leads to oxidative damage due to an increase in free iron caused by hematocyte destruction. Thirty-one male ICR mice were randomly divided into 3 groups: a rested control group, an intense-exercise group, and a group rested for 24 hours after intense exercise. The serum haptoglobin level of the intense-exercise group decreased compared with that of the rested control group, suggesting hemolysis. Tissue iron and protein carbonyl levels in the liver were increased after exercise, and the protein carbonyl level in the spleen on the day after exercise was significantly increased compared with that of the resting state. These results suggest that the spleen and liver, where extravascular hemolysis occurs, were subjected to oxidative modification by the free iron, which was released from large numbers of hemocytes that were destroyed due to the intense exercise.

  15. Absolute intensity measurements of the CO2 bands 401-III /backward arrow/ 000 and 411-III /backward arrow/ 010

    NASA Technical Reports Server (NTRS)

    Valero, F. P. J.

    1977-01-01

    The absolute intensities of the studied transitions of CO2 have been measured from spectra obtained under high resolution. Vibration-rotation line intensities and integrated band intensities are reported. The studied bands are characterized by origins at 7593.5 and 7584 cm to the minus 1. Spectra were obtained by an Ames' 25-m base path White-type absorption cell equipped with silver-coated mirrors together with a 5-m focal length Czerny-Turner scanning spectrometer. The procedures for calculating the widths and intensities are explained, and uncertainty limits of the reported values are considered.

  16. 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

  17. Intensity of swimming exercise influences aortic reactivity in rats

    PubMed Central

    Brito, A.F.; Silva, A.S.; Souza, I.L.L.; Pereira, J.C.; da Silva, B.A.

    2015-01-01

    Exercise is known to cause a vasodilatory response; however, the correlation between the vasorelaxant response and different training intensities has not been investigated. Therefore, this study evaluated the vascular reactivity and lipid peroxidation after different intensities of swimming exercise in rats. Male Wistar rats (aged 8 weeks; 250-300 g) underwent forced swimming for 1 h whilst tied to loads of 3, 4, 5, 6, and 8% of their body weight, respectively (groups G3, G4, G5, G6 and G8, respectively; n=5 each). Immediately after the test, the aorta was removed and suspended in an organ bath. Cumulative relaxation in response to acetylcholine (10−12-10−4 M) and contraction in response to phenylephrine (10−12-10−5 M) were measured. Oxidative stress was estimated by determining malondialdehyde concentration. The percentages of aorta relaxation were significantly higher in G3 (7.9±0.20), G4 (7.8±0.29), and G5 (7.9±0.21), compared to the control group (7.2±0.04), while relaxation in the G6 (7.4±0.25) and G8 (7.0±0.06) groups was similar to the control group. In contrast, the percentage of contraction was significantly higher in G6 (8.8 ±0.1) and G8 (9.7±0.29) compared to the control (7.1±0.1), G3 (7.3±0.2), G4 (7.2±0.1) and G5 (7.2±0.2%) groups. Lipid peroxidation levels in the aorta were similar to control levels in G3, G4 and G5, but higher in G6 and G8, and significantly higher in G8 (one-way ANOVA). These results indicate a reduction in vasorelaxing activity and an increase in contractile activity in rat aortas after high-intensity exercise, followed by an increase in lipid peroxidation. PMID:26397974

  18. 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…

  19. Absolute phase recovery in structured light illumination systems: Sinusoidal vs. intensity discrete patterns

    NASA Astrophysics Data System (ADS)

    Porras-Aguilar, Rosario; Falaggis, Konstantinos

    2016-09-01

    Structured light illumination is a well-established technology for noncontact 3D surface measurements. A common challenge in those systems is to obtain the absolute surface information using few measurement frames. This work discusses techniques based on the projection of multiple sinusoidal fringe patterns with different fringe period, as well as the projection of intensity discrete Gray Code and grey-level coded patterns. The use of sinusoidal multi-frequency techniques has been since years an on-going area of research, where various algorithms have been developed based on beats, look-up tables, or number-theoretical approaches. This work shows that a related technique, the so-called algebraic reconstruction technique that is borrowed from the area of multi-wavelength interferometry can be used for this purpose. This approach provides a robust analytical solution to the phase-unwrapping problem. However, this work argues that despite these advances, the acquisition of additional phase maps obtained with different fringe periods requires too many measurement frames, and hence is inefficient. Motivated by that, this work proposes a new grey level coding scheme that uses only few measurement frames, overcomes typical defocus errors, and has an error detecting feature. The latter feature makes the need of separate error detecting algorithms obsolete. This so-called closed-loop space filling curve can be implemented with an arbitrary number of N grey-levels enabling to code up to (2N) code-words. The performance of this so-called closed-loop space filling curve is demonstrated using experimental data.

  20. Metabolic and hormonal responses to isoenergetic high-intensity interval exercise and continuous moderate-intensity exercise.

    PubMed

    Peake, Jonathan M; Tan, Sok Joo; Markworth, James F; Broadbent, James A; Skinner, Tina L; Cameron-Smith, David

    2014-10-01

    This study investigated the effects of high-intensity interval training (HIIT) vs. work-matched moderate-intensity continuous exercise (MOD) on metabolism and counterregulatory stress hormones. In a randomized and counterbalanced order, 10 well-trained male cyclists and triathletes completed a HIIT session [81.6 ± 3.7% maximum oxygen consumption (V̇o2 max); 72.0 ± 3.2% peak power output; 792 ± 95 kJ] and a MOD session (66.7 ± 3.5% V̇o2 max; 48.5 ± 3.1% peak power output; 797 ± 95 kJ). Blood samples were collected before, immediately after, and 1 and 2 h postexercise. Carbohydrate oxidation was higher (P = 0.037; 20%), whereas fat oxidation was lower (P = 0.037; -47%) during HIIT vs. MOD. Immediately after exercise, plasma glucose (P = 0.024; 20%) and lactate (P < 0.01; 5.4×) were higher in HIIT vs. MOD, whereas total serum free fatty acid concentration was not significantly different (P = 0.33). Targeted gas chromatography-mass spectromtery metabolomics analysis identified and quantified 49 metabolites in plasma, among which 11 changed after both HIIT and MOD, 13 changed only after HIIT, and 5 changed only after MOD. Notable changes included substantial increases in tricarboxylic acid intermediates and monounsaturated fatty acids after HIIT and marked decreases in amino acids during recovery from both trials. Plasma adrenocorticotrophic hormone (P = 0.019), cortisol (P < 0.01), and growth hormone (P < 0.01) were all higher immediately after HIIT. Plasma norepinephrine (P = 0.11) and interleukin-6 (P = 0.20) immediately after exercise were not significantly different between trials. Plasma insulin decreased during recovery from both HIIT and MOD (P < 0.01). These data indicate distinct differences in specific metabolites and counterregulatory hormones following HIIT vs. MOD and highlight the value of targeted metabolomic analysis to provide more detailed insights into the metabolic demands of exercise.

  1. Blood Volume Changes Induced By Low-Intensity Intradialytic Exercise in Long-Term Hemodialysis Patients.

    PubMed

    Ookawara, Susumu; Miyazawa, Haruhisa; Ito, Kiyonori; Ueda, Yuichiro; Kaku, Yoshio; Hirai, Keiji; Hoshino, Taro; Mori, Honami; Yoshida, Izumi; Morishita, Yoshiyuki; Tabei, Kaoru

    2016-01-01

    Intradialytic exercise-induced blood volume (BV) reduction may cause intradialytic hypotension in hemodialysis (HD) patients. However, BV recovery time after intradialytic exercise remains unknown. Hemodialysis patients were recruited, and their relative BV change (%ΔBV) were measured with intradialytic exercise (n = 12). After confirming the linearity of %ΔBV for 30 min, patients exercised using a stationary cycle in the supine position. The target exercise intensity was a 10% increase in heart rate (HR), corresponding to relatively low-intensity exercise. Baseline %ΔBV (assumed baseline) were calculated for the 30 min before exercise using linear regression analysis. The mean intradialytic exercise start and end times after HD initiation were 93.0 ± 8.4 and 116.4 ± 8.3 min, respectively, a mean exercise duration of 23.5 ± 2.6 min. Percentage change in blood volume declined rapidly upon exercise initiation and gradually increased above the assumed baseline throughout HD. At the end of HD, %ΔBV in the exercise group was significantly higher than the assumed baseline (measured - assumed baseline %ΔBV: 2.17 ± 0.62%; p = 0.02). Intradialytic exercise with low intensity in the supine position attenuated ultrafiltration-induced BV reduction at the end of HD. Therefore, intradialytic exercise may prevent intradialytic hypotension during later HD, although its intensity was relatively low level. PMID:26720736

  2. Is Moderate Intensity Exercise Training Combined with High Intensity Interval Training More Effective at Improving Cardiorespiratory Fitness than Moderate Intensity Exercise Training Alone?

    PubMed Central

    Roxburgh, Brendon H.; Nolan, Paul B.; Weatherwax, Ryan M.; Dalleck, Lance C.

    2014-01-01

    The purpose of this study was to compare the effectiveness of either continuous moderate intensity exercise training (CMIET) alone vs. CMIET combined with a single weekly bout of high intensity interval training (HIIT) on cardiorespiratory fitness. Twenty nine sedentary participants (36.3 ± 6.9 yrs) at moderate risk of cardiovascular disease were recruited for 12 weeks of exercise training on a treadmill and cycle ergometer. Participants were randomised into three groups: CMIET + HIIT (n = 7; 8-12 x 60 sec at 100% VO2max, 150 sec active recovery), CMIET (n = 6; 30 min at 45-60% oxygen consumption reserve (VO2R)) and a sedentary control group (n = 7). Participants in the CMIET + HIIT group performed a single weekly bout of HIIT and four weekly sessions of CMIET, whilst the CMIET group performed five weekly CMIET sessions. Probabilistic magnitude-based inferences were determined to assess the likelihood that the true value of the effect represents substantial change. Relative VO2max increased by 10.1% (benefit possible relative to control) in in the CMIET + HIIT group (32.7 ± 9.2 to 36.0 ± 11.5 mL·kg-1·min-1) and 3.9% (benefit possible relative to control) in the CMIET group (33.2 ± 4.0 to 34.5 ± 6.1 mL·kg-1·min-1), whilst there was a 5.7% decrease in the control group (30.0 ± 4.6 to 28.3 ± 6.5 mL·kg-1·min-1). It was ‘unclear’ if a clinically significant difference existed between the effect of CMIET + HIIT and CMIET on the change in VO2max. Both exercising groups showed clinically meaningful improvements in VO2max. Nevertheless, it remains ‘unclear’ whether one type of exercise training regimen elicits a superior improvement in cardiorespiratory fitness relative to its counterpart. Key Points Both continuous moderate intensity exercise training (CMIET) alone and CMIET combined with a single weekly bout of high intensity interval training (CMIET + HIIT) elicit ‘possibly beneficial’ clinically meaningful improvements in cardiorespiratory

  3. 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.

  4. Decline in executive control during acute bouts of exercise as a function of exercise intensity and fitness level.

    PubMed

    Labelle, Véronique; Bosquet, Laurent; Mekary, Saïd; Bherer, Louis

    2013-02-01

    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 for key methodological confounds. Thirty-seven participants (M(age)=23. 8 years; SD=2.6) completed a computerized modified-Stroop task (involving denomination, inhibition and switching conditions) while pedalling at 40%, 60% and 80% of their peak power output (PPO). Results showed that in the switching condition of the task, error rates increased as a function of exercise intensity (from 60% to 80% of PPO) in all participants and that lower fit individuals showed increased reaction time variability. This suggests that acute bouts of cardiovascular exercise can momentarily alter executive control and increase performance instability in lower fit individuals. PMID:23146780

  5. Brain Glycogen Decreases During Intense Exercise Without Hypoglycemia: The Possible Involvement of Serotonin.

    PubMed

    Matsui, Takashi; Soya, Shingo; Kawanaka, Kentaro; Soya, Hideaki

    2015-07-01

    Brain glycogen stored in astrocytes, a source of lactate as a neuronal energy source, decreases during prolonged exercise with hypoglycemia. However, brain glycogen dynamics during exercise without hypoglycemia remain unknown. Since intense exercise increases brain noradrenaline and serotonin as known inducers for brain glycogenolysis, we hypothesized that brain glycogen decreases with intense exercise not accompanied by hypoglycemia. To test this hypothesis, we employed a well-established acute intense exercise model of swimming in rats. Rats swam for fourteen 20 s bouts with a weight equal to 8 % of their body mass and were sacrificed using high-power (10 kW) microwave irradiation to inactivate brain enzymes for accurate detection of brain glycogen and monoamines. Intense exercise did not alter blood glucose, but did increase blood lactate levels. Immediately after exercise, brain glycogen decreased and brain lactate increased in the hippocampus, cerebellum, cortex, and brainstem. Simultaneously, serotonin turnover in the hippocampus and brainstem mutually increased and were associated with decreased brain glycogen. Intense swimming exercise that does not induce hypoglycemia decreases brain glycogen associated with increased brain lactate, implying an importance of glycogen in brain energetics during intense exercise even without hypoglycemia. Activated serotonergic regulation is a possible underlying mechanism for intense exercise-induced glycogenolysis at least in the hippocampus and brainstem.

  6. The influence of acute intense exercise on exogenous spatial attention depends on physical fitness level.

    PubMed

    Llorens, Francesc; Sanabria, Daniel; Huertas, Florentino

    2015-01-01

    We investigated the effect of a previous bout of intense exercise on exogenous spatial attention. In Experiment 1, a group of participants performed an exogenous spatial task at rest (without prior effort), immediately after intense exercise, and after recovering from an intense exercise. The analyses revealed that the typical "facilitation effect" (i.e., faster reaction times on cued than on uncued trials) immediately after exercise was positively correlated with participants' fitness level. In Experiment 2, a high-fit and a low-fit group performed the same task at rest (without prior effort) and immediately after an intense exercise. Results revealed that, after the bout of exercise, only low-fit participants showed reduced attentional effects compared to the rest condition. We argue that the normal functioning of exogenous attention was influenced by intense effort, affecting low-fit participants to a larger extent than to high-fit participants. As a consequence, target processing was prioritized over irrelevant stimuli.

  7. 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. PMID:27377137

  8. 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.

  9. Investigation of Intensity Levels during Video Classroom Exercise Sessions

    ERIC Educational Resources Information Center

    Caldwell, Thad; Ratliffe, Tom

    2014-01-01

    Classroom Exercises for the Body and Brain was developed in the state of Georgia by the HealthMPowers organization to help classroom teachers provide structured physical activity for their elementary students in their classrooms. These brief video exercises were designed for students to participate at their desks as exercise breaks, as energy…

  10. 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.

  11. Responses of sex steroid hormones to different intensities of exercise in endurance athletes.

    PubMed

    Sato, Koji; Iemitsu, Motoyuki; Katayama, Keisho; Ishida, Koji; Kanao, Yoji; Saito, Mitsuru

    2016-01-01

    Previous studies have shown that acute exercise elevates sex steroid hormone concentrations in rodents and that sprint exercise increases circulating testosterone in healthy young men. However, the effect of different exercise intensities on sex steroid hormone responses at different levels of physical fitness is still unclear. In this study, we compared circulating sex steroid hormone responses at different exercise intensities in athletes and non-athletes. Eight male endurance athletes and 11 non-athletes performed two 15 min sessions of submaximal exercise at 40 and 70% peak oxygen uptake (V̇(O2peak)), respectively, and exercised at 90% V̇(O2peak) until exhaustion. Venous blood samples were collected during the last minute of each submaximal exercise session and immediately after exhaustion. Acute exercise at 40, 70 and 90% V̇(O2peak) induced significant increases in serum dehydroepiandrosterone (DHEA) and free testosterone concentrations in non-athletes. On the contrary, only 90% V̇O2 peak exercise led to an increase in serum DHEA and free testosterone concentrations in athletes. Serum 5α-dihydrotestosterone concentrations increased with 90% V̇(O2peak) exercise in both athletes and non-athletes. Additionally, serum estradiol concentrations were significantly increased at moderate and high exercise intensities in both athletes and non-athletes. These results indicate that in endurance athletes, serum sex steroid hormone concentrations, especially serum DHEA and 5α-dihydrotestosterone concentrations, increased only with high-intensity exercise, suggesting that different responses of sex steroid hormone secretion are induced by different exercise intensities in individuals with low and high levels of physical fitness. In athletes, therefore, high-intensity exercise may be required to increase circulating sex steroid hormone concentrations.

  12. 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…

  13. 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.

  14. Absolute integrated intensity and individual line parameters for the 6.2-micron band of NO2. [in solar spectrum

    NASA Technical Reports Server (NTRS)

    Goldman, A.; Bonomo, F. S.; Williams, W. J.; Murcray, D. G.; Snider, D. E.

    1975-01-01

    The absolute integrated intensity of the 6.2-micron band of NO2 at 40 C was determined from quantitative spectra at about 10 per cm resolution by the spectral band model technique. A value of 1430 plus or minus 300 per sq cm per atm was obtained. Individual line parameters, positions, intensities, and ground-state energies were derived, and line-by-line calculations were compared with the band model results and with the quantitative spectra obtained at about 0.5 per cm resolution.

  15. 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.

  16. 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.

  17. 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

  18. Neurophysiological and behavioral correlates of cognitive control during low and moderate intensity exercise.

    PubMed

    Olson, Ryan L; Chang, Yu-Kai; Brush, Christopher J; Kwok, Andrea N; Gordon, Valentina X; Alderman, Brandon L

    2016-05-01

    The aim of this study was to examine neurophysiological and behavioral correlates of cognitive control elicited by a modified flanker task while exercising at low and moderate intensities. A secondary aim was to examine cognitive control processes at several time points during an acute bout of exercise to determine whether cognition is selectively influenced by the duration of exercise. Twenty-seven healthy participants completed a modified version of the Eriksen flanker task while exercising on a cycle ergometer at 40% and 60% VO2 peak and during a no-exercise seated control across three separate days. During task performance, continuous EEG was collected to assess neurocognitive function using the N2 and P3 event-related brain potentials (ERPs). Neurocognitive performance was assessed at 5, 15, and 25min time points during steady-state exercise. Regardless of intensity, behavioral findings revealed impaired accuracy during both exercise conditions for the flanker task trials that require greater cognitive control. However, faster reaction times were found during moderate-intensity exercise. Neuroelectric measures revealed increased N2 and P3 amplitudes during both exercise conditions relative to rest. Together, these findings suggest divergent effects of exercise on behavioral performance measures accompanied by an upregulation of cognitive control during aerobic exercise. These impairments are discussed in terms of dual-task paradigms and the transient hypofrontality theory. PMID:26458515

  19. 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.

  20. High-Intensity Intermittent Exercise: Effect on Young People's Cardiometabolic Health and Cognition.

    PubMed

    Cooper, Simon B; Dring, Karah J; Nevill, Mary E

    2016-01-01

    With only a quarter of young people currently meeting physical activity guidelines, two key areas of concern are the effects of exercise on cardiometabolic health and cognition. Despite the fact that physical activity in young people is typically high intensity and intermittent in nature, much of the literature examines traditional endurance-type exercise. This review provides an update on the effects of high-intensity intermittent exercise on young people's cardiometabolic health and cognition. High-intensity intermittent exercise has acute beneficial effects on endothelial function and postprandial lipemia and chronic positive effects on weight management. In addition, there is emerging evidence regarding chronic benefits on the blood lipid profile, blood pressure, and proinflammatory and anti-inflammatory cytokines. Furthermore, emerging evidence suggests beneficial acute and chronic effects of high-intensity intermittent exercise on cognition. However, further research is required in both cardiometabolic health and cognition, particularly regarding the impact of school-based interventions in adolescents. PMID:27399821

  1. Absolute radiometric calibration of Als intensity data: effects on accuracy and target classification.

    PubMed

    Kaasalainen, Sanna; Pyysalo, Ulla; Krooks, Anssi; Vain, Ants; Kukko, Antero; Hyyppä, Juha; Kaasalainen, Mikko

    2011-01-01

    Radiometric calibration of airborne laser scanning (ALS) intensity data aims at retrieving a value related to the target scattering properties, which is independent on the instrument or flight parameters. The aim of a calibration procedure is also to be able to compare results from different flights and instruments, but practical applications are sparsely available, and the performance of calibration methods for this purpose needs to be further assessed. We have studied the radiometric calibration with data from three separate flights and two different instruments using external calibration targets. We find that the intensity data from different flights and instruments can be compared to each other only after a radiometric calibration process using separate calibration targets carefully selected for each flight. The calibration is also necessary for target classification purposes, such as separating vegetation from sand using intensity data from different flights. The classification results are meaningful only for calibrated intensity data.

  2. Absolute radiometric calibration of Als intensity data: effects on accuracy and target classification.

    PubMed

    Kaasalainen, Sanna; Pyysalo, Ulla; Krooks, Anssi; Vain, Ants; Kukko, Antero; Hyyppä, Juha; Kaasalainen, Mikko

    2011-01-01

    Radiometric calibration of airborne laser scanning (ALS) intensity data aims at retrieving a value related to the target scattering properties, which is independent on the instrument or flight parameters. The aim of a calibration procedure is also to be able to compare results from different flights and instruments, but practical applications are sparsely available, and the performance of calibration methods for this purpose needs to be further assessed. We have studied the radiometric calibration with data from three separate flights and two different instruments using external calibration targets. We find that the intensity data from different flights and instruments can be compared to each other only after a radiometric calibration process using separate calibration targets carefully selected for each flight. The calibration is also necessary for target classification purposes, such as separating vegetation from sand using intensity data from different flights. The classification results are meaningful only for calibrated intensity data. PMID:22346660

  3. 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

  4. Quantitative Vapor-phase IR Intensities and DFT Computations to Predict Absolute IR Spectra based on Molecular Structure: I. Alkanes

    SciTech Connect

    Williams, Stephen D.; Johnson, Timothy J.; Sharpe, Steven W.; Yavelak, Veronica; Oats, R. P.; Brauer, Carolyn S.

    2013-11-13

    Recently recorded quantitative IR spectra of a variety of gas-phase alkanes are shown to have integrated intensities in both the C-H stretching and C-H bending regions that depend linearly on the molecular size, i.e. the number of C-H bonds. This result is well predicted from CH4 to C15H32 by DFT computations of IR spectra at the B3LYP/6-31+G(d,p) level of DFT theory. A simple model predicting the absolute IR band intensities of alkanes based only on structural formula is proposed: For the C-H stretching band near 2930 cm-1 this is given by (in km/mol): CH¬_str = (34±3)*CH – (41±60) where CH is number of C-H bonds in the alkane. The linearity is explained in terms of coordinated motion of methylene groups rather than the summed intensities of autonomous -CH2- units. The effect of alkyl chain length on the intensity of a C-H bending mode is explored and interpreted in terms of conformer distribution. The relative intensity contribution of a methyl mode compared to the total C-H stretch intensity is shown to be linear in the number of terminal methyl groups in the alkane, and can be used to predict quantitative spectra a priori based on structure alone.

  5. Absolute Line Intensities in the ν 3Band of 12CH 3F by Diode-Laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Lepère, Muriel; Blanquet, Ghislain; Walrand, Jacques

    1996-06-01

    Infrared absolute line intensities of the ν 3band of 12CH 3F have been measured around 9.5 μm using a diode-laser spectrometer. These line strengths were obtained from the equivalent width method and, for a few lines, by fitting a Rautian profile to the measured shape of the lines. From these results, we have deduced the vibrational bandstrength ( Sv0= 379.2 ± 5.9 cm -2·atm -1at 296 K) and the first Herman-Wallis factor (α = 0.35 × 10 -3± 0.10 × 10 -3).

  6. Absolute Line Intensities in the 2ν 02 Band of Cyanogen Chloride at 12.8 μm

    NASA Astrophysics Data System (ADS)

    Lepère, Muriel; Blanquet, Ghislain; Walrand, Jacques

    2000-05-01

    Absolute line intensities were measured at high resolution with a tunable diode laser. This work concerns the 2ν02 band of cyanogen chloride ClCN in the region 780 cm-1. Thirty-two absorption lines were recorded for the isotopomer 35ClCN and 26 lines for 37ClCN. From the analysis of these lines, we determined the bandstrengths: S0v = 19.14 cm-2 atm-1 for 35ClCN and S0v = 17.84 cm-2 atm-1 for 37ClCN.

  7. Assessment of absolute added correlative coding in optical intensity modulation and direct detection channels

    NASA Astrophysics Data System (ADS)

    Dong-Nhat, Nguyen; Elsherif, Mohamed A.; Malekmohammadi, Amin

    2016-06-01

    The performance of absolute added correlative coding (AACC) modulation format with direct detection has been numerically and analytically reported, targeting metro data center interconnects. Hereby, the focus lies on the performance of the bit error rate, noise contributions, spectral efficiency, and chromatic dispersion tolerance. The signal space model of AACC, where the average electrical and optical power expressions are derived for the first time, is also delineated. The proposed modulation format was also compared to other well-known signaling, such as on-off-keying (OOK) and four-level pulse-amplitude modulation, at the same bit rate in a directly modulated vertical-cavity surface-emitting laser-based transmission system. The comparison results show a clear advantage of AACC in achieving longer fiber delivery distance due to the higher dispersion tolerance.

  8. Fatigue during high-intensity intermittent exercise: application to bodybuilding.

    PubMed

    Lambert, Charles P; Flynn, Michael G

    2002-01-01

    Resistance exercise is an activity performed by individuals interested in competition, those who wish to improve muscle mass and strength for other sports, and for individuals interested in improving their strength and physical appearance. In this review we present information suggesting that phosphocreatine depletion, intramuscular acidosis and carbohydrate depletion are all potential causes of the fatigue during resistance exercise. In addition, recommendations are provided for nutritional interventions, which might delay muscle fatigue during this type of activity.

  9. Low Intensity Exercise Training Improves Skeletal Muscle Regeneration Potential

    PubMed Central

    Pietrangelo, Tiziana; Di Filippo, Ester S.; Mancinelli, Rosa; Doria, Christian; Rotini, Alessio; Fanò-Illic, Giorgio; Fulle, Stefania

    2015-01-01

    Purpose: The aim of this study was to determine whether 12 days of low-to-moderate exercise training at low altitude (598 m a.s.l.) improves skeletal muscle regeneration in sedentary adult women. Methods: Satellite cells were obtained from the vastus lateralis skeletal muscle of seven women before and after this exercise training at low altitude. They were investigated for differentiation aspects, superoxide anion production, antioxidant enzymes, mitochondrial potential variation after a depolarizing insult, intracellular Ca2+ concentrations, and micro (mi)RNA expression (miR-1, miR-133, miR-206). Results: In these myogenic populations of adult stem cells, those obtained after exercise training, showed increased Fusion Index and intracellular Ca2+ concentrations. This exercise training also generally reduced superoxide anion production in cells (by 12–67%), although not in two women, where there was an increase of ~15% along with a reduced superoxide dismutase activity. miRNA expression showed an exercise-induced epigenetic transcription profile that was specific according to the reduced or increased superoxide anion production of the cells. Conclusions: The present study shows that low-to-moderate exercise training at low altitude improves the regenerative capacity of skeletal muscle in adult women. The differentiation of cells was favored by increased intracellular calcium concentration and increased the fusion index. This low-to-moderate training at low altitude also depicted the epigenetic signature of cells. PMID:26733888

  10. 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.

  11. Intense Exercise during the First Two Trimesters of Unapparent Pregnancy: Case Reports.

    ERIC Educational Resources Information Center

    Cohen, Gloria C.; And Others

    1989-01-01

    This report presents nonexperimental retrospective data on the weights, menstrual cycle intervals, pregnancy symptoms, and running programs of two women who exercised intensely during their first two trimesters. Although these two cases suggest that strenuous anaerobic exercise during pregnancy is not harmful, more studies are needed. (IAH)

  12. 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…

  13. Emotional Responsiveness after Low- and Moderate-Intensity Exercise and Seated Rest.

    ERIC Educational Resources Information Center

    Smith, J. Carson; O'Connor, Patrick J.; Crabbe, James B.; Dishman, Rod K.

    2002-01-01

    Examined whether anxiety-reducing conditions of low- and moderate-intensity cycling exercise would lead to changes in emotional responsiveness to pictures designed to elicit pleasant neutral, and unpleasant emotions among healthy female college students. Results indicated that cycling exercise resulted in decreased baseline activity of facial…

  14. The Time Course Effect of Moderate Intensity Exercise on Response Execution and Response Inhibition

    ERIC Educational Resources Information Center

    Joyce, Jennifer; Graydon, Jan; McMorris, Terry; Davranche, Karen

    2009-01-01

    This research aimed to investigate the time course effect of a moderate steady-state exercise session on response execution and response inhibition using a stop-task paradigm. Ten participants performed a stop-signal task whilst cycling at a carefully controlled workload intensity (40% of maximal aerobic power), immediately following exercise and…

  15. Hypoglycemia during moderate intensity exercise reduces counterregulatory responses to subsequent hypoglycemia.

    PubMed

    Cade, W Todd; Khoury, Nadia; Nelson, Suzanne; Shackleford, Angela; Semenkovich, Katherine; Krauss, Melissa J; Arbeláez, Ana María

    2016-09-01

    Hypoglycemia, which occurs commonly during and following exercise in people with diabetes, is thought to be due to attenuated counterregulation in the setting of therapeutic insulin excess. To better understand the pathophysiology of counterregulation, we aimed to determine if dextrose administration to maintain euglycemia during moderate intensity exercise alters the attenuation of counterregulatory responses to subsequent hypoglycemia in healthy adults : Counterregulatory responses to hypoglycemia were assessed in 18 healthy adults after bed rest and following exercise with (n = 9) and without (n = 9) dextrose infusion. Responses were measured during a stepped euglycemic-hypoglycemic clamp 24 h after either bed rest or two 90-min bouts of exercise at 70% peak oxygen uptake : Hypoglycemia occurred during the second bout of exercise without dextrose infusion. Plasma glucagon and epinephrine responses to stepped hypoglycemia after antecedent exercise without dextrose infusion were significantly lower at the 45 mg/dL glycemic level compared to after bed rest. However, no attenuation of the counterregulatory responses to hypoglycemia was evident after antecedent exercise when dextrose was infused. This study suggests that the attenuation of the counterregulatory responses during hypoglycemia after exercise is likely due to the hypoglycemia that occurs during moderate prolonged exercise and not solely due to exercise or its intensity. PMID:27597762

  16. 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. PMID:26951480

  17. 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

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

    PubMed

    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

  19. Transient Increase in Homocysteine but Not Hyperhomocysteinemia during Acute Exercise at Different Intensities in Sedentary Individuals

    PubMed Central

    Iglesias-Gutiérrez, Eduardo; Egan, Brendan; Díaz-Martínez, Ángel Enrique; Peñalvo, José Luis; González-Medina, Antonio; Martínez-Camblor, Pablo; O’Gorman, Donal J.; Úbeda, Natalia

    2012-01-01

    Considering that hyperhomocysteinemia is an independent risk factor for cardiovascular disease, the purpose of this study was to determine the kinetics of serum homocysteine (tHcy) and the vitamins involved in its metabolism (folates, B12, and B6) in response to acute exercise at different intensities. Eight sedentary males (18–27 yr) took part in the study. Subjects were required to complete two isocaloric (400 kcal) acute exercise trials on separate occasions at 40% (low intensity, LI) and 80% VO2peak (high intensity, HI). Blood samples were drawn at different points before (pre4 and pre0 h), during (exer10, exer20, exer30, exer45, and exer60 min), and after exercise (post0, post3, and post19 h). Dietary, genetic, and lifestyle factors were controlled. Maximum tHcy occurred during exercise, both at LI (8.6 (8.0–10.1) µmol/L, 9.3% increase from pre0) and HI (9.4 (8.2–10.6) µmol/L, 25.7% increase from pre0), coinciding with an accumulated energy expenditure independent of the exercise intensity. From this point onwards tHcy declined until the cessation of exercise and continued descending. At post19, tHcy was not different from pre-exercise values. No values of hyperhomocysteinemia were observed at any sampling point and intensity. In conclusion, acute exercise in sedentary individuals, even at HI, shows no negative effect on tHcy when at least 400 kcal are spent during exercise and the nutritional status for folate, B12, and B6 is adequate, since no hyperhomocysteinemia has been observed and basal concentrations were recovered in less than 24 h. This could be relevant for further informing healthy exercise recommendations. PMID:23236449

  20. 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.

  1. High Intensity Exercise in Multiple Sclerosis: Effects on Muscle Contractile Characteristics and Exercise Capacity, a Randomised Controlled Trial

    PubMed Central

    Vandenabeele, Frank; Grevendonk, Lotte; Verboven, Kenneth; Hansen, Dominique

    2015-01-01

    Introduction Low-to-moderate intensity exercise improves muscle contractile properties and endurance capacity in multiple sclerosis (MS). The impact of high intensity exercise remains unknown. Methods Thirty-four MS patients were randomized into a sedentary control group (SED, n = 11) and 2 exercise groups that performed 12 weeks of a high intensity interval (HITR, n = 12) or high intensity continuous cardiovascular training (HCTR, n = 11), both in combination with resistance training. M.vastus lateralis fiber cross sectional area (CSA) and proportion, knee-flexor/extensor strength, body composition, maximal endurance capacity and self-reported physical activity levels were assessed before and after 12 weeks. Results Compared to SED, 12 weeks of high intensity exercise increased mean fiber CSA (HITR: +21±7%, HCTR: +23±5%). Furthermore, fiber type I CSA increased in HCTR (+29±6%), whereas type II (+23±7%) and IIa (+23±6%,) CSA increased in HITR. Muscle strength improved in HITR and HCTR (between +13±7% and +45±20%) and body fat percentage tended to decrease (HITR: -3.9±2.0% and HCTR: -2.5±1.2%). Furthermore, endurance capacity (Wmax +21±4%, time to exhaustion +24±5%, VO2max +17±5%) and lean tissue mass (+1.4±0.5%) only increased in HITR. Finally self-reported physical activity levels increased 73±19% and 86±27% in HCTR and HITR, respectively. Conclusion High intensity cardiovascular exercise combined with resistance training was safe, well tolerated and improved muscle contractile characteristics and endurance capacity in MS. Trial Registration ClinicalTrials.gov NCT01845896 PMID:26418222

  2. Exercise Intensity and Recovery: Biomarkers of Injury, Inflammation, and Oxidative Stress.

    PubMed

    Bessa, Artur L; Oliveira, Vanessa N; Agostini, Guilherme G; Oliveira, Renato J S; Oliveira, Ana C S; White, Gillian E; Wells, Greg D; Teixeira, David N S; Espindola, Foued S

    2016-02-01

    Biomarkers of inflammation, muscle damage, and oxidative stress after high-intensity exercise have been described previously; however, further understanding of their role in the postexercise recovery period is necessary. Because these markers have been implicated in cell signaling, they may be specifically related to the training adaptations induced by high-intensity exercise. Thus, a clear model showing their responses to exercise may be useful in characterizing the relative recovery status of an athlete. The purpose of this study was twofold: (a) to investigate the time course of markers of muscle damage and inflammation in the blood from 3 to 72 hours after combined training exercises and (b) to investigate indicators of oxidative stress and damage associated with increased reactive oxygen species production during high-intensity exercise in elite athletes. Nineteen male athletes performed a combination of high-intensity aerobic and anaerobic training exercises. Samples were acquired immediately before and at 3, 6, 12, 24, 48, and 72 hours after exercise. The appearance and clearance of creatine kinase and lactate dehydrogenase in the blood occurred faster than previous studies have reported. The neutrophil/lymphocyte ratio summarizes the mobilization of 2 leukocyte subpopulations in a single marker and may be used to predict the end of the postexercise recovery period. Further analysis of the immune response using serum cytokines indicated that high-intensity exercise performed by highly trained athletes only generated inflammation that was localized to the skeletal muscle. Biomarkers are not a replacement for performance tests, but when used in conjunction, they may offer a better indication of metabolic recovery status. Therefore, the use of biomarkers can improve a coach's ability to assess the recovery period after an exercise session and to establish the intensity of subsequent training sessions.

  3. Moderate intensity of regular exercise improves cardiac SR Ca2+ uptake activity in ovariectomized rats.

    PubMed

    Bupha-Intr, Tepmanas; Laosiripisan, Jitanan; Wattanapermpool, Jonggonnee

    2009-10-01

    The impact of regular exercise in protecting cardiac deteriorating results of female sex hormone deprivation was evaluated by measuring changes in intracellular Ca2+ removal activity of sarcoplasmic reticulum (SR) in ovariectomized rats following 9-wk treadmill running exercise at moderate intensity. Despite induction of cardiac hypertrophy in exercised groups of both sham-operated and ovariectomized rats, exercise training had no effect on SR Ca2+ uptake and SR Ca(2+)-ATPase (SERCA) in hormone intact rat heart. However, exercise training normalized the suppressed maximum SR Ca2+ uptake and SERCA activity in ovariectomized rat heart. While exercise training normalized the leftward shift in pCa (-log[Ca2+])-SR Ca2+ uptake relation in ovariectomized rats, no effect was detected in exercised sham-operated rats. Similar phenomena were also observed on SERCA and on phospholamban (PLB) phosphorylation levels; exercise training in ovariectomized rats enhanced SERCA expression to reach the level as that in sham-operated rats, in which there were no differences in SERCA and phospho-PLB levels between sedentary and exercised groups. In addition, the reduction in phospho-Thr(17) PLB in myocardium of ovariectomized rats was abolished by exercise training. These results showed that regular exercise maintains the molecular activation of cardiac SR Ca2+ uptake under normal physiological conditions and is able to induce a protective impact on cardiac SR Ca2+ uptake in ovarian sex hormone-deprived status.

  4. Evidence that the talk test can be used to regulate exercise intensity.

    PubMed

    Woltmann, Michaela L; Foster, Carl; Porcari, John P; Camic, Clayton L; Dodge, Christopher; Haible, Stephanie; Mikat, Richard P

    2015-05-01

    The Talk Test (TT) has been shown to be a surrogate of the ventilatory threshold and to be a viable alternative to standard methods of prescribing exercise training intensity. The TT has also been shown to be responsive to manipulations known to change physiologic function including blood donation and training. Whether the TT can be used independently to regulated training intensity is not known. Physically active volunteers (N = 16) performed an incremental exercise test to identify stages of the TT (Last Positive [LP], Equivocal [EQ], and Negative [NEG]). In subsequent, randomly ordered, 30-minute steady-state runs, the running velocity was regulated solely by "clamping" the TT response desired and then monitoring the response of conventional markers of exercise intensity (heart rate, blood lactate, rating of perceived exertion). All subjects were able to complete the LP stage, but only 13 of 16 and 2 of 16 subjects were able to complete the EQ and NEG stages, respectively. Physiologic responses were broadly within those predicted from the incremental exercise test and within the appropriate range of physiologic responses for exercise training. Thus, in addition to correlating with convenient physiological markers, the TT can be used proactively to guide exercise training intensity. The LP stage produced training intensities compatible with appropriate training intensity in healthy adults and with recovery sessions or long duration training sessions in athletes. The EQ and NEG stages produced intensities compatible with higher intensity training in athletes. The results demonstrate that the TT can be used as a primary method to control exercise training intensity. PMID:25536539

  5. Absolute Rovibrational Intensities of C-12O2-16 Absorption Bands in the 3090-3850/ CM Spectral Region

    NASA Technical Reports Server (NTRS)

    Devi, V. Malathy; Benner, D. Chris; Rinsland, Curtis P.; Smith, Mary Ann H.

    1998-01-01

    A multispectrum nonlinear least-squares fitting technique has been used to determine the absolute intensities for approximately 1500 spectral lines in 36 vibration - rotation bands Of C-12O2-16 between 3090 and 3850/ cm. A total of six absorption spectra of a high- purity (99.995% minimum) natural sample of carbon dioxide were used in the analysis. The spectral data (0.01/cm resolution) were recorded at room temperature and low pressure (1 to 10 Torr) using the McMath-Pierce Fourier transform spectrometer of the National Solar Observatory (NSO) on Kitt Peak. The absorption path lengths for these spectra varied between 24.86 and 385.76 m. The first experimental determination of the intensity of the theoretically predicted 2(nu)(sub 2, sup 2) + nu(sub 3) "forbidden" band has been made. The measured line intensities obtained for each band have been analyzed to determine the vibrational band intensity, S(sub nu), in /cm/( molecule/sq cm) at 296 K, square of the rotationless transition dipole moment |R|(exp 2) in Debye, as well as the nonrigid rotor coefficients. The results are compared to the values listed in the 1996 HITRAN database which are obtained using the direct numerical diagonalization (DND) technique as well as to other published values where available.

  6. Moderate and Vigorous Intensity Exercise during Pregnancy and Gestational Weight Gain in Women with Gestational Diabetes

    PubMed Central

    Ehrlich, Samantha F.; Sternfeld, Barbara; Krefman, Amy E.; Hedderson, Monique M.; Brown, Susan D.; Mevi, Ashley; Chasan-Taber, Lisa; Quesenberry, Charles P.; Ferrara, Assiamira

    2016-01-01

    Objectives To estimate the associations of moderate and vigorous intensity exercise during pregnancy with the rate of gestational weight gain (GWG) from gestational diabetes (GDM) diagnosis to delivery, overall and stratified by prepregnancy overweight/obesity. Methods Prospective cohort study with physical activity reported shortly after the GDM diagnosis and prepregnancy weight and post-diagnosis GWG obtained from electronic medical records (n= 1,055). Multinomial logistic regression models in the full cohort and stratified by prepregnancy overweight/obesity estimated associations of moderate and vigorous intensity exercise with GWG below and above the Institute of Medicine’s (IOM) prepregnancy BMI-specific recommended ranges for weekly rate of GWG in the second and third trimesters. Results In the full cohort, any participation in vigorous intensity exercise was associated with decreased odds of GWG above recommended ranges as compared to no participation [Odds Ratio (95% Confidence Interval): 0.63 (0.40, 0.99)], with a significant trend for decreasing odds of excess GWG with increasing level of vigorous intensity exercise. Upon stratification by prepregnancy overweight/obesity, significant associations were only observed for BMI ≥ 25.0 kg/m2: any vigorous intensity exercise, as compared to none, was associated with 54% decreased odds of excess GWG [0.46 (0.27, 0.79)] and significant trends were detected for decreasing odds of GWG both below and above the IOM’s recommended ranges with increasing level of vigorous exercise (both P ≤ 0.03). No associations were observed for moderate intensity exercise. Conclusions In women with GDM, particularly overweight and obese women, vigorous intensity exercise during pregnancy may reduce the odds of excess GWG. PMID:26955997

  7. Absolute Intensities of γ Rays Emitted in the Decay of 239U

    NASA Astrophysics Data System (ADS)

    Griffin, Henry C.

    2008-08-01

    A source of 239U was produced by the 238U(n,γ)239U reactions and was purified by radiochemistry. Disintegration rates were determined by 4π counting in a liquid scintillation spectrometer, and gamma emission rates were determined by counting liquid samples with well-characterized HPGe spectrometers. The prominent 74.7-keV γ ray was found to occur in 53.9(5)% of the decays, and this value was used to obtain intensities for L and K x-rays and γ rays from 31 to 1102 keV.

  8. The effect of high intensity interval exercise on postprandial triacylglycerol and leukocyte activation--monitored for 48 h post exercise.

    PubMed

    Gabriel, Brendan Morris; Pugh, Jamie; Pruneta-Deloche, Valerie; Moulin, Philippe; Ratkevicius, Aivaras; Gray, Stuart Robert

    2013-01-01

    Postprandial phenomenon are thought to contribute to atherogenesis alongside activation of the immune system. A single bout of high intensity interval exercise attenuates postprandial triacylglycerol (TG), although the longevity and mechanisms underlying this observation are unknown. The aims of this study were to determine whether this attenuation in postprandial TG remained 2 days after high intensity interval exercise, to monitor markers of leukocyte activation and investigate the underlying mechanisms. Eight young men each completed two three day trials. On day 1: subjects rested (Control) or performed 5 x 30 s maximal sprints (high intensity interval exercise). On day 2 and 3 subjects consumed high fat meals for breakfast and 3 h later for lunch. Blood samples were taken at various times and analysed for TG, glucose and TG-rich lipoprotein (TRL)-bound LPL-dependent TRL-TG hydrolysis (LTTH). Flow cytometry was used to evaluate granulocyte, monocyte and lymphocyte CD11b and CD36 expression. On day 2 after high intensity interval exercise TG area under the curve was lower (P<0.05) (7.46 ± 1.53 mmol/l/7h) compared to the control trial (9.47 ± 3 .04 mmol/l/7h) with no differences during day 3 of the trial. LTTH activity was higher (P<0.05) after high intensity interval exercise, at 2 hours of day 2, compared to control. Granulocyte, monocyte and lymphocyte CD11b expression increased with time over day 2 and 3 of the study (P<0.0001). Lymphocyte and monocyte CD36 expression decreased with time over day 2 and 3 (P<0.05). There were no differences between trials in CD11b and CD36 expression on any leukocytes. A single session of high intensity interval exercise attenuated postprandial TG on day 2 of the study, with this effect abolished by day 3.The reduction in postprandial TG was associated with an increase in LTTH. High intensity interval exercise had no effect on postprandial responses of CD11b or CD36.

  9. Long term high intensity exercise and damage of small joints in rheumatoid arthritis

    PubMed Central

    de Jong, Z; Munneke, M; Zwinderman, A; Kroon, H; Ronday, K; Lems, W; Dijkmans, B; Breedveld, F; Vliet, V; Hazes, J; Huizinga, T

    2004-01-01

    Objective: To investigate the effect of long term high intensity weightbearing exercises on radiological damage of the joints of the hands and feet in patients with rheumatoid arthritis (RA). Methods: Data of the 281 completers of a 2 year randomised controlled trial comparing the effects of usual care physical therapy (UC) with high intensity weightbearing exercises were analysed for the rate of radiological joint damage (Larsen score) of the hands and feet. Potential determinants of outcome were defined: disease activity, use of drugs, change in physical capacity and in bone mineral density, and attendance rate at exercise sessions. Results: After 2 years, the 136 participants in high intensity weightbearing exercises developed significantly less radiological damage than the 145 participants in UC. The mean (SD) increase in damage was 3.5 (7.9) in the exercise group and 5.7 (10.2) in the UC group, p = 0.045. Separate analysis of the damage to the hands and feet suggests that this difference in rate of increase of damage is more pronounced in the joints of the feet than in the hands. The rate of damage was independently associated with less disease activity, less frequent use of glucocorticoids, and with an improvement in aerobic fitness. Conclusion: The progression of radiological joint damage of the hands and feet in patients with RA is not increased by long term high intensity weightbearing exercises. These exercises may have a protective effect on the joints of the feet. PMID:15479889

  10. Exercise Intensity Guidelines for Cancer Survivors: a Comparison with Reference Values.

    PubMed

    Gil-Rey, E; Quevedo-Jerez, K; Maldonado-Martin, S; Herrero-Román, F

    2014-11-27

    The optimal dose of physical activity (PA) in cancer survivors (CS) is unknown due to the large variety of types of cancer, illness stages and treatments, low cardiorespiratory fitness, and physical inactivity. It is recommended that CS follow current PA guidelines for healthy population. There are no specific exercise prescription guidelines for CS. To know the cardiorespiratory parameters of CS in order to create exercise prescription guidelines for this population, 152 inactive CS were recruited to perform a cardiopulmonary exercise test. Peak oxygen uptake (VO2peak), ventilatory threshold (VT) and respiratory compensation point (RCP) determined 3 exercise intensity zones to create exercise intensity classification guidelines for CS. VO2peak (18.7±4.6 mL·kg(-1)·min(-1)) and peak heart rate (HRpeak) (145.1±17.9 bpm) were lower than the estimated values (p<0.001). Moderate intensity zone for CS was different from the current PA guidelines for healthy population: 41-64% VO2max, 55-70% HRmax, 23-48% HRres, 2.5-4 METs and 8-14 points on RPE scale. Intensities in PA guidelines for healthy population are not adapted to the characteristics of CS. For individual exercise prescription in CS specific PA guidelines should be used in order to maximize the benefits obtained by the use of aerobic exercise training.

  11. Beta decay of the fission product 125Sb and a new complete evaluation of absolute gamma ray transition intensities

    NASA Astrophysics Data System (ADS)

    Rajput, M. U.; Ali, N.; Hussain, S.; Mujahid, S. A.; MacMahon, D.

    2012-04-01

    The radionuclide 125Sb is a long-lived fission product, which decays to 125Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

  12. Affective responses after different intensities of exercise in patients with traumatic brain injury

    PubMed Central

    Rzezak, Patricia; Caxa, Luciana; Santolia, Patricia; Antunes, Hanna K. M.; Suriano, Italo; Tufik, Sérgio; de Mello, Marco T.

    2015-01-01

    Background: Patients with traumatic brain injury (TBI) usually have mood and anxiety symptoms secondary to their brain injury. Exercise may be a cost-effective intervention for the regulation of the affective responses of this population. However, there are no studies evaluating the effects of exercise or the optimal intensity of exercise for this clinical group. Methods: Twelve male patients with moderate or severe TBI [mean age of 31.83 and SD of 9.53] and 12 age- and gender-matched healthy volunteers [mean age of 30.58 and SD of 9.53] participated in two sessions of exercise of high and moderate-intensity. Anxiety and mood was evaluated, and subjective assessment of experience pre- and post-exercise was assessed. A mixed between and within-subjects general linear model (GLM) analysis was conducted to compare groups [TBI, control] over condition [baseline, session 1, session 2] allowing for group by condition interaction to be determined. Planned comparisons were also conducted to test study hypotheses. Results: Although no group by condition interaction was observed, planned comparisons indicated that baseline differences between patients and controls in anxiety (Cohens’ d = 1.80), tension (d = 1.31), depression (d = 1.18), anger (d = 1.08), confusion (d = 1.70), psychological distress (d = 1.28), and physical symptoms (d = 1.42) disappear after one session of exercise, independently of the intensity of exercise. Conclusion: A single-section of exercise, regardless of exercise intensity, had a positive effect on the affective responses of patients with TBI both by increasing positive valence feelings and decreasing negative ones. Exercise can be an easily accessible intervention that may alleviate depressive symptoms related to brain injury. PMID:26161074

  13. Beta-endorphin immunoreactivity during high-intensity exercise with and without opiate blockade.

    PubMed

    Angelopoulos, T J

    2001-11-01

    Nine highly fit men [mean (SE) maximum oxygen uptake, VO2max: 63.9 (1.7) ml x kg(-1) x min(-1); age 27.6 (1.6) years] were studied during two treadmill exercise trials to determine plasma beta-endorphin immunoreactivity during intense exercise (80% VO2max). A double-blind experimental design was used, and subjects performed the two exercise trials in counterbalanced order. Exercise trials were 30 min in duration and were conducted 7 days apart. One exercise trial was undertaken following administration of naloxone (1.2 3 cm3) and the other after receiving a placebo (0.9% NaCl saline; 3 cm3). Prior to each experimental trial, a flexible catheter was placed into an antecubital vein and baseline blood samples were collected. Thereafter, each subject received either a naloxone or placebo bolus injection. Blood samples were also collected after 10, 20 and 30 min of continuous exercise. beta-Endorphin was higher (P < 0.05) during exercise when compared to pre-exercise in both trials. However, no statistically significant difference was found (P> 0.05) between exercise time points within either experimental trial. beta-endorphin immunoreactivity was greater (P < 0.05) in the naloxone than in the placebo trial during each exercise sampling time point [10 min: 63.7 (3.9) pg x ml(-1) vs 78.7 (3.8) pg x ml(-1); 20 min: 68.7 (4.1) pg x ml(-1) vs (4.3) pg x ml(-1); 30 min: 71.0 (4.3) pg x ml(-1) vs 82.5(3.2) pg x ml(-1)]. These data suggest that intense exer induces significant increases in beta-endorphin that are maintained over time during steady-rate exercise. Exercise and naloxone had an interactive effect on beta-endorphin release that warrants further investigation. PMID:11820329

  14. Effect of exercise intensity and volume on persistence of insulin sensitivity during training cessation.

    PubMed

    Bajpeyi, Sudip; Tanner, Charles J; Slentz, Cris A; Duscha, Brian D; McCartney, Jennifer S; Hickner, Robert C; Kraus, William E; Houmard, Joseph A

    2009-04-01

    The purpose of this study was to determine whether exercise prescriptions differing in volume or intensity also differ in their ability to retain insulin sensitivity during an ensuing period of training cessation. Sedentary, overweight/obese subjects were assigned to one of three 8-mo exercise programs: 1) low volume/moderate intensity [equivalent of approximately 12 miles/wk, 1,200 kcal/wk at 40-55% peak O(2) consumption (Vo(2peak)), 200 min exercise/wk], 2) low volume/vigorous intensity ( approximately 12 miles/wk, 1,200 kcal/wk at 65-80% Vo(2peak), 125 min/wk), and 3) high volume/vigorous intensity ( approximately 20 miles/wk, 2,000 kcal/wk at 65-80% Vo(2peak), 200 min/wk). Insulin sensitivity (intravenous glucose tolerance test, S(I)) was measured when subjects were sedentary and at 16-24 h and 15 days after the final training bout. S(I) increased with training compared with the sedentary condition (P < or = 0.05) at 16-24 h with all of the exercise prescriptions. S(I) decreased to sedentary, pretraining values after 15 days of training cessation in the low-volume/vigorous-intensity group. In contrast, at 15 days S(I) was significantly elevated compared with sedentary (P < or = 0.05) in the prescriptions utilizing 200 min/wk (low volume/moderate intensity, high volume/vigorous intensity). In the high-volume/vigorous-intensity group, indexes of muscle mitochondrial density followed a pattern paralleling insulin action by being elevated at 15 days compared with pretraining; this trend was not evident in the low-volume/moderate-intensity group. These findings suggest that in overweight/obese subjects a relatively chronic persistence of enhanced insulin action may be obtained with endurance-oriented exercise training; this persistence, however, is dependent on the characteristics of the exercise training performed.

  15. Achilles tendon biomechanics in response to acute intense exercise.

    PubMed

    Joseph, Michael F; Lillie, Kurtis R; Bergeron, Daniel J; Cota, Kevin C; Yoon, Joseph S; Kraemer, William J; Denegar, Craig R

    2014-05-01

    Achilles tendinopathy is a common disorder and is more prevalent in men. Although differences in tendon mechanics between men and women have been reported, understanding of tendon mechanics in young active people is limited. Moreover, there is limited understanding of changes in tendon mechanics in response to acute exercise. Our purpose was to compare Achilles tendon mechanics in active young adult men and women at rest and after light and strenuous activity in the form of repeated jumping with an added load. Participants consisted of 17 men and 14 women (18-30 years) who were classified as being at least moderately physically active as defined by the International Physical Activity Questionnaire. Tendon force/elongation measures were obtained during an isometric plantarflexion contraction on an isokinetic dynamometer with simultaneous ultrasound imaging of the Achilles tendon approximate to the soleus myotendinous junction. Data were collected at rest, after a 10-minute treadmill walk, and after a fatigue protocol of 100 toe jumps performed in a Smith machine, with a load equaling 20% of body mass. We found greater tendon elongation, decreased stiffness, and lower Young's modulus only in women after the jumping exercise. Force and stress were not different between groups but decreased subsequent to the jumping exercise bout. In general, women had greater elongation and strain, less stiffness, and a lower Young's modulus during plantarflexor contraction. These data demonstrate differences in tendon mechanics between men and women and suggest a potential protective mechanism explaining the lower incidence of Achilles tendinopathy in women.

  16. Effect of Short-Term, High-Intensity Exercise on Anaerobic Threshold in Women.

    ERIC Educational Resources Information Center

    Evans, Blanche W.

    This study investigated the effects of a six-week, high-intensity cycling program on anaerobic threshold (AT) in ten women. Subjects trained four days a week using high-intensity interval-type cycle exercises. Workouts included six 4-minute intervals cycling at 85 percent maximal oxygen uptake (VO sub 2 max), separated by 3-minute intervals of…

  17. Low-Volume Intense Exercise Elicits Post-exercise Hypotension and Subsequent Hypervolemia, Irrespective of Which Limbs Are Exercised

    PubMed Central

    Graham, Matthew J.; Lucas, Samuel J. E.; Francois, Monique E.; Stavrianeas, Stasinos; Parr, Evelyn B.; Thomas, Kate N.; Cotter, James D.

    2016-01-01

    Introduction: Exercise reduces arterial and central venous blood pressures during recovery, which contributes to its valuable anti-hypertensive effects and to facilitating hypervolemia. Repeated sprint exercise potently improves metabolic function, but its cardiovascular effects (esp. hematological) are less well-characterized, as are effects of exercising upper versus lower limbs. The purposes of this study were to identify the acute (<24 h) profiles of arterial blood pressure and blood volume for (i) sprint intervals versus endurance exercise, and (ii) sprint intervals using arms versus legs. Methods: Twelve untrained males completed three cycling exercise trials; 50-min endurance (legs), and 5*30-s intervals using legs or arms, in randomized and counterbalanced sequence, at a standardized time of day with at least 8 days between trials. Arterial pressure, hemoglobin concentration and hematocrit were measured before, during and across 22 h after exercise, the first 3 h of which were seated rest. Results: The post-exercise hypotensive response was larger after leg intervals than endurance (AUC: 7540 ± 3853 vs. 3897 ± 2757 mm Hg·min, p = 0.049, 95% CI: 20 to 6764), whereas exercising different limbs elicited similar hypotension (arms: 6420 ± 3947 mm Hg·min, p = 0.48, CI: −1261 to 3896). In contrast, arterial pressure at 22 h was reduced after endurance but not after leg intervals (−8 ± 8 vs. 0 ± 7 mm Hg, p = 0.04, CI: 7 ± 7) or reliably after arm intervals (−4 ± 8 mm Hg, p = 0.18 vs. leg intervals). Regardless, plasma volume expansion at 22 h was similar between leg intervals and endurance (both +5 ± 5%; CI: −5 to 5%) and between leg and arm intervals (arms: +5 ± 7%, CI: −8 to 5%). Conclusions: These results emphasize the relative importance of central and/or systemic factors in post-exercise hypotension, and indicate that markedly diverse exercise profiles can induce substantive hypotension and subsequent hypervolemia. At least for endurance

  18. The role of exercise intensity in the bone metabolic response to an acute bout of weight-bearing exercise.

    PubMed

    Scott, Jonathan P R; Sale, Craig; Greeves, Julie P; Casey, Anna; Dutton, John; Fraser, William D

    2011-02-01

    We compared the effects of exercise intensity (EI) on bone metabolism during and for 4 days after acute, weight-bearing endurance exercise. Ten males [mean ± SD maximum oxygen uptake (Vo(2max)): 56.2 ± 8.1 ml·min(-1)·kg(-1)] completed three counterbalanced 8-day trials. Following three control days, on day 4, subjects completed 60 min of running at 55%, 65%, and 75% Vo(2max). Markers of bone resorption [COOH-terminal telopeptide region of collagen type 1 (β-CTX)] and formation [NH(2)-terminal propeptides of procollagen type 1 (P1NP), osteocalcin (OC), bone-alkaline phosphatase (ALP)], osteoprotegerin (OPG), parathyroid hormone (PTH), albumin-adjusted calcium (ACa), phosphate (PO(4)), and cortisol were measured during and for 3 h after exercise and on four follow-up days (FU1-FU4). At 75% Vo(2max), β-CTX was not significantly increased from baseline by exercise but was higher compared with 55% (17-19%, P < 0.01) and 65% (11-13%, P < 0.05) Vo(2max) in the first hour postexercise. Concentrations were decreased from baseline in all three groups by 39-42% (P < 0.001) at 3 h postexercise but not thereafter. P1NP increased (P < 0.001) during exercise only, while bone-ALP was increased (P < 0.01) at FU3 and FU4, but neither were affected by EI. PTH and cortisol increased (P < 0.001) with exercise at 75% Vo(2max) only and were higher (P < 0.05) than at 55% and 65% Vo(2max) during and immediately after exercise. The increases (P < 0.001) in OPG, ACa, and PO(4) with exercise were not affected by EI. Increasing EI from 55% to 75% Vo(2max) during 60 min of running resulted in higher β-CTX concentrations in the first hour postexercise but had no effect on bone formation markers. Increased bone-ALP concentrations at 3 and 4 days postexercise suggest a beneficial effect of this type of exercise on bone mineralization. The increase in OPG was not influenced by exercise intensity, whereas PTH was increased at 75% Vo(2max) only, which cannot be fully explained by changes in

  19. Influence of Prior Intense Exercise and Cold Water Immersion in Recovery for Performance and Physiological Response during Subsequent Exercise.

    PubMed

    Christensen, Peter M; Bangsbo, Jens

    2016-01-01

    Athletes in intense endurance sports (e.g., 4000-m track cycling) often perform maximally (~4 min) twice a day due to qualifying and finals being placed on the same day. The purpose of the present study was to evaluate repeated performance on the same day in a competitive setting (part A) and the influence from prior intense exercise on subsequent performance and physiological response to moderate and maximal exercise with and without the use of cold water immersion (CWI) in recovery (part B). In part A, performance times during eight World championships for male track cyclists were extracted from the qualifying and final races in 4000-m individual pursuit. In part B, twelve trained cyclists with an average (±SD) ⩒O2-peak of 67 ± 5 mL/min/kg performed a protocol mimicking a qualifying race (QUAL) followed 3 h later by a performance test (PT) with each exercise period encompassing intense exercise for ~4 min preceded by an identical warm-up period in both a control setting (CON) and using cold water immersion in recovery (CWI; 15 min at 15°C). Performance was lowered (P < 0.001) from qualification to finals (259 ± 3 vs. 261 ± 3 s) for the track cyclists during World championships in part A. In part B, mean power in PT was not different in CWI relative to CON (406 ± 43 vs. 405 ± 38 W). Peak ⩒O2 (5.04 ± 0.50 vs. 5.00 ± 0.49 L/min) and blood lactate (13 ± 3 vs. 14 ± 3 mmol/L) did not differ between QUAL and PT and cycling economy and potassium handling was not impaired by prior intense exercise. In conclusion, performance is reduced with repeated maximal exercise in world-class track cyclists during 4000-m individual pursuit lasting ~4 min, however prior intense exercise do not appear to impair peak ⩒O2, peak lactate, cycling economy, or potassium handling in trained cyclists and CWI in recovery does not improve subsequent performance. PMID:27445857

  20. Influence of Prior Intense Exercise and Cold Water Immersion in Recovery for Performance and Physiological Response during Subsequent Exercise.

    PubMed

    Christensen, Peter M; Bangsbo, Jens

    2016-01-01

    Athletes in intense endurance sports (e.g., 4000-m track cycling) often perform maximally (~4 min) twice a day due to qualifying and finals being placed on the same day. The purpose of the present study was to evaluate repeated performance on the same day in a competitive setting (part A) and the influence from prior intense exercise on subsequent performance and physiological response to moderate and maximal exercise with and without the use of cold water immersion (CWI) in recovery (part B). In part A, performance times during eight World championships for male track cyclists were extracted from the qualifying and final races in 4000-m individual pursuit. In part B, twelve trained cyclists with an average (±SD) ⩒O2-peak of 67 ± 5 mL/min/kg performed a protocol mimicking a qualifying race (QUAL) followed 3 h later by a performance test (PT) with each exercise period encompassing intense exercise for ~4 min preceded by an identical warm-up period in both a control setting (CON) and using cold water immersion in recovery (CWI; 15 min at 15°C). Performance was lowered (P < 0.001) from qualification to finals (259 ± 3 vs. 261 ± 3 s) for the track cyclists during World championships in part A. In part B, mean power in PT was not different in CWI relative to CON (406 ± 43 vs. 405 ± 38 W). Peak ⩒O2 (5.04 ± 0.50 vs. 5.00 ± 0.49 L/min) and blood lactate (13 ± 3 vs. 14 ± 3 mmol/L) did not differ between QUAL and PT and cycling economy and potassium handling was not impaired by prior intense exercise. In conclusion, performance is reduced with repeated maximal exercise in world-class track cyclists during 4000-m individual pursuit lasting ~4 min, however prior intense exercise do not appear to impair peak ⩒O2, peak lactate, cycling economy, or potassium handling in trained cyclists and CWI in recovery does not improve subsequent performance.

  1. Influence of Prior Intense Exercise and Cold Water Immersion in Recovery for Performance and Physiological Response during Subsequent Exercise

    PubMed Central

    Christensen, Peter M.; Bangsbo, Jens

    2016-01-01

    Athletes in intense endurance sports (e.g., 4000-m track cycling) often perform maximally (~4 min) twice a day due to qualifying and finals being placed on the same day. The purpose of the present study was to evaluate repeated performance on the same day in a competitive setting (part A) and the influence from prior intense exercise on subsequent performance and physiological response to moderate and maximal exercise with and without the use of cold water immersion (CWI) in recovery (part B). In part A, performance times during eight World championships for male track cyclists were extracted from the qualifying and final races in 4000-m individual pursuit. In part B, twelve trained cyclists with an average (±SD) ⩒O2-peak of 67 ± 5 mL/min/kg performed a protocol mimicking a qualifying race (QUAL) followed 3 h later by a performance test (PT) with each exercise period encompassing intense exercise for ~4 min preceded by an identical warm-up period in both a control setting (CON) and using cold water immersion in recovery (CWI; 15 min at 15°C). Performance was lowered (P < 0.001) from qualification to finals (259 ± 3 vs. 261 ± 3 s) for the track cyclists during World championships in part A. In part B, mean power in PT was not different in CWI relative to CON (406 ± 43 vs. 405 ± 38 W). Peak ⩒O2 (5.04 ± 0.50 vs. 5.00 ± 0.49 L/min) and blood lactate (13 ± 3 vs. 14 ± 3 mmol/L) did not differ between QUAL and PT and cycling economy and potassium handling was not impaired by prior intense exercise. In conclusion, performance is reduced with repeated maximal exercise in world-class track cyclists during 4000-m individual pursuit lasting ~4 min, however prior intense exercise do not appear to impair peak ⩒O2, peak lactate, cycling economy, or potassium handling in trained cyclists and CWI in recovery does not improve subsequent performance. PMID:27445857

  2. Metabolic and hormonal responses during repeated bouts of brief and intense exercise: effects of pre-exercise glucose ingestion.

    PubMed

    Wouassi, D; Mercier, J; Ahmaidi, S; Brun, J F; Mercier, B; Orsetti, A; Préfaut, C

    1997-01-01

    We investigated metabolic and hormonal responses during repeated bouts of brief and intense exercise (a force-velocity test; Fv test) and examined the effect of glucose ingestion on these responses and on exercise performance. The test was performed twice by seven subjects [27 (2) years] according to a double-blind randomized crossover protocol. During the experimental trial (GLU), the subjects ingested 500 ml of glucose polymer solution containing 25 g glucose 15 min before starting the exercise. During the control trial (CON), the subjects received an equal volume of sweet placebo (aspartame). Exercise performance was assessed by calculating peak anaerobic power (W(an,peak)). Venous plasma lactate concentration increased significantly during the Fv test (P < 0.001), but no difference was found between CON and GLU. Blood glucose first decreased significantly from the beginning of exercise up to the 6-kg load (P < 0.001) and then increased significantly at W(an,peak) and for up to 10 min during the recovery period (P < 0.001) in both CON and GLU. Insulin concentrations decreased significantly in both groups, but were higher at W(an,peak) in GLU compared with CON (P < 0.05). Glucagon and epinephrine did not change significantly in either group, but epinephrine was significantly lower in GLU after glucose ingestion (P < 0.05) and at W(an,peak) (P < 0.05). W(an,peak) was not significantly different between CON and GLU. In conclusion, blood glucose and insulin concentrations decreased during repeated bouts of brief and intense exercise, while blood lactate concentration increased markedly without any significant change in glucagon and epinephrine concentrations. Glucose ingestion altered metabolic and hormonal responses during the Fv test, but the performance as measured by W(an,peak) was not changed.

  3. Absence of Respiratory Muscle Fatigue in High-Intensity Continuous or Interval Cycling Exercise.

    PubMed

    Kurti, Stephanie P; Smith, Joshua R; Emerson, Sam R; Castinado, Kenneth M; Harms, Craig A

    2015-11-01

    Respiratory muscle fatigue (RMF) occurs during prolonged exercise (∼15-20 minutes) at >85% V[Combining Dot Above]O2max. However, RMF has been reported to occur in ∼3-6 minutes in various modes of exercise at a high intensity. It is not known if continuous cycling exercise vs. repeated bouts of high-intensity interval training (HIT) at >85% V[Combining Dot Above]O2max will lead to RMF. We hypothesized that RMF would occur after a constant load test and would be present before end exercise in an HIT protocol. Eight moderately active healthy men (21.7 ± 1.7 years; 181.3 ± 5.2 cm; 81.3 ± 2.3 kg) completed a V[Combining Dot Above]O2max test on a cycle ergometer. Subjects then completed 2 bouts of HIT (7 × 1 minute, 2-minute recovery between intervals) and 3 bouts of continuous exercise (CE) tests at 90% of peak power (determined from an incremental exercise test to exhaustion). Maximal inspiratory pressure (PIMAX) and expiratory pressure (PEMAX) were measured pre- and post-exercise for both HIT and CE and after each interval during HIT. Decreases in postexercise PIMAX and PEMAX compared with baseline were used to determine RMF. There were no differences (p > 0.05) in PIMAX or PEMAX pre- to post-exercise for HIT (PIMAX pre: 134 ± 51, post: 135 ± 50 cmH2O; PEMAX pre: 143 ± 41, post: 148 ± 46 cmH2O) or CE (PIMAX pre: 135 ± 54, post: 133 ± 52 cmH2O; PEMAX pre: 146 ± 46, post: 148 ± 46 cmH2O) indicating RMF was not present following CE and HIT. These data suggest that repeated high-intensity cycling exercise at 90% peak power in a CE or HIT protocol does not lead to RMF.

  4. 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.

  5. Central hemodynamic responses during acute high-intensity interval exercise and moderate continuous exercise in patients with heart failure.

    PubMed

    Gayda, Mathieu; Normandin, Eve; Meyer, Philippe; Juneau, Martin; Haykowsky, Mark; Nigam, Anil

    2012-12-01

    The aim of this study was to compare the acute hemodynamic responses during high-intensity intermittent exercise (HIIE) session compared with moderate-intensity continuous exercise (MICE) session in patients with heart failure and reduced ejection fraction (HFREF). Thirteen patients with HFREF (age, 59 ± 6 years; left ventricular ejection fraction, 27% ± 6%; New York Heart Association class I to III) were randomly assigned to a single session of HIIE (2 × 8 min) corresponding to 30 s at 100% of peak power output (PPO) and 30 s passive recovery intervals or to a MICE (22 min) at 60% of PPO. Gas exchange and central hemodynamic parameters (cardiac bioimpedance) were measured continuously during exercise. Oxygen uptake, stroke volume (SV), cardiac output (CO), and arterio-venous difference (C(a-v)O(2)) were compared. Mean oxygen uptake and ventilation were lower during HIIE vs. MICE. CO, SV, and C(a-v)O(2)) were not different between MICE and HIIE. Optimized HIIE was well tolerated (similar perceived exertion) and no significant ventricular arrhythmias and (or) abnormal blood pressure responses occurred during HIEE session. Compared with MICE, optimized HIIE elicited similar central hemodynamic and C(a-v)O(2) responses in HFREF patients with lower oxygen uptake and ventilation. HIIE may be an efficient exercise training modality in patients with HFREF.

  6. Analog Exercise Hardware to Implement a High Intensity Exercise Program During Bed Rest

    NASA Technical Reports Server (NTRS)

    Loerch, Linda; Newby, Nate; Ploutz-Snyder, Lori

    2012-01-01

    Background: In order to evaluate novel countermeasure protocols in a space flight analog prior to validation on the International Space Station (ISS), NASA's Human Research Program (HRP) is sponsoring a multi-investigator bedrest campaign that utilizes a combination of commercial and custom-made exercise training hardware to conduct daily resistive and aerobic exercise protocols. This paper will describe these pieces of hardware and how they are used to support current bedrest studies at NASA's Flight Analog Research Unit in Galveston, TX. Discussion: To implement candidate exercise countermeasure studies during extended bed rest studies the following analog hardware are being utilized: Stand alone Zero-Gravity Locomotion Simulator (sZLS) -- a custom built device by NASA, the sZLS allows bedrest subjects to remain supine as they run on a vertically-oriented treadmill (0-15 miles/hour). The treadmill includes a pneumatic subject loading device to provide variable body loading (0-100%) and a harness to keep the subject in contact with the motorized treadmill to provide a ground reaction force at their feet that is quantified by a Kistler Force Plate. Supine Cycle Ergometer -- a commercially available supine cycle ergometer (Lode, Groningen, Netherlands) is used for all cycle ergometer sessions. The ergometer has adjustable shoulder supports and handgrips to help stabilize the subject during exercise. Horizontal Squat Device (HSD) -- a custom built device by Quantum Fitness Corp (Stafford, TX), the HSD allows for squat exercises to be performed while lying in a supine position. The HSD can provide 0 to 600 pounds of force in selectable 5 lb increments, and allows hip translation in both the vertical and horizontal planes. Prone Leg Curl -- a commercially available prone leg curl machine (Cybex International Inc., Medway, MA) is used to complete leg curl exercises. Horizontal Leg Press -- a commercially available horizontal leg press (Quantum Fitness Corporation) is

  7. Dissociation of Increases in PGC-1α and Its Regulators from Exercise Intensity and Muscle Activation Following Acute Exercise

    PubMed Central

    Hankinson, Paul B.; Simpson, Craig A.; Little, Jonathan P.; Graham, Ryan B.; Gurd, Brendon J.

    2013-01-01

    Muscle activation as well as changes in peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) following high-intensity interval exercise (HIIE) were examined in young healthy men (n  = 8; age, 21.9±2.2 yrs; VO2peak, 53.1±6.4 ml/min/kg; peak work rate, 317±23.5 watts). On each of 3 visits HIIE was performed on a cycle ergometer at a target intensity of 73, 100, or 133% of peak work rate. Muscle biopsies were taken at rest and three hours after each exercise condition. Total work was not different between conditions (∼730 kJ) while average power output (73%, 237±21; 100%, 323±26; 133%, 384±35 watts) and EMG derived muscle activation (73%, 1262±605; 100%, 2089±737; 133%, 3029±1206 total integrated EMG per interval) increased in an intensity dependent fashion. PGC-1α mRNA was elevated after all three conditions (p<0.05), with a greater increase observed following the 100% condition (∼9 fold, p<0.05) compared to both the 73 and 133% conditions (∼4 fold). When expressed relative to muscle activation, the increase in PGC-1α mRNA for the 133% condition was less than that for the 73 and 100% conditions (p<0.05). SIRT1 mRNA was also elevated after all three conditions (∼1.4 fold, p<0.05), with no difference between conditions. These findings suggest that intensity-dependent increases in PGC-1α mRNA following submaximal exercise are largely due to increases in muscle recruitment. As well, the blunted response of PGC-1α mRNA expression following supramaximal exercise may indicate that signalling mediated activation of PGC-1α may also be blunted. We also indentify that increases in PDK4, SIRT1, and RIP140 mRNA following acute exercise are dissociated from exercise intensity and muscle activation, while increases in EGR1 are augmented with supramaximal HIIE (p<0.05). PMID:23951207

  8. Effect of high-intensity interval exercise on basal triglyceride metabolism in non-obese men.

    PubMed

    Bellou, Elena; Magkos, Faidon; Kouka, Tonia; Bouchalaki, Eirini; Sklaveniti, Dimitra; Maraki, Maria; Tsekouras, Yiannis E; Panagiotakos, Demosthenes B; Kavouras, Stavros A; Sidossis, Labros S

    2013-08-01

    A single bout of high-intensity interval aerobic exercise has been shown to produce the same or greater metabolic benefits as continuous endurance exercise with considerably less energy expenditure, but whether this applies to very low density lipoprotein (VLDL) metabolism is not known. We sought to examine the effect of a single bout of high-intensity interval aerobic exercise on basal VLDL-triglyceride (TG) kinetics 14 and 48 h after exercise cessation to determine the acute and time-dependent effects of this type of exercise on VLDL-TG metabolism. Eight healthy sedentary men (age, 23.6 ± 6.1 years; body mass index, 23.1 ± 2.2 kg·m(-2), peak oxygen consumption (V̇O2peak), 36.3 ± 5.5 mL·kg(-1)·min(-1)) participated in three stable isotopically labeled tracer infusion studies: (i) 14 h and (ii) 48 h after a single bout of high-intensity aerobic interval exercise (60% and 90% of V̇O2peak in 4 min intervals for a total of 32 min; gross energy expenditure ∼500 kcal) and (iii) after an equivalent period of rest, in random order. Fasting plasma VLDL-TG concentration was 20% lower at 14 h (P = 0.046) but not at 48 h (P = 1.000) after exercise compared with the resting trial. VLDL-TG plasma clearance rate increased by 21% at 14 h (P < 0.001) but not at 48 h (P = 0.299) after exercise compared with rest, whereas hepatic VLDL-TG secretion rate was not different from rest at any time point after exercise. We conclude that high-intensity interval exercise reduces fasting plasma VLDL-TG concentrations in non-obese men the next day by augmenting VLDL-TG clearance, just like a single bout of continuous endurance exercise. This effect is short-lived and abolished by 48 h after exercise.

  9. Local infusion of ascorbate augments NO-dependent cutaneous vasodilatation during intense exercise in the heat.

    PubMed

    Meade, Robert D; Fujii, Naoto; Alexander, Lacy M; Paull, Gabrielle; Louie, Jeffrey C; Flouris, Andreas D; Kenny, Glen P

    2015-09-01

    Recent work demonstrates that nitric oxide (NO) contributes to cutaneous vasodilatation during moderate (400 W of metabolic heat production) but not high (700 W of metabolic heat production) intensity exercise bouts performed in the heat (35°C). The present study evaluated whether the impairment in NO-dependent cutaneous vasodilatation was the result of a greater accumulation of reactive oxygen species during high (700 W of metabolic heat production) relative to moderate (500 W of metabolic heat production) intensity exercise. It was shown that local infusion of ascorbate (an anti-oxidant) improves NO-dependent forearm cutaneous vasodilatation during high intensity exercise in the heat. These findings provide novel insight into the physiological mechanisms governing cutaneous blood flow during exercise-induced heat stress and provide direction for future research exploring whether oxidative stress underlies the impairments in heat dissipation that may occur in older adults, as well as in individuals with pathophysiological conditions such as type 2 diabetes. Nitric oxide (NO)-dependent cutaneous vasodilatation is reportedly diminished during exercise performed at a high (700 W) relative to moderate (400 W) rate of metabolic heat production. The present study evaluated whether this impairment results from increased oxidative stress associated with an accumulation of reactive oxygen species (ROS) during high intensity exercise. On two separate days, 11 young (mean ± SD, 24 ± 4 years) males cycled in the heat (35°C) at a moderate (500 W) or high (700 W) rate of metabolic heat production. Each session included two 30 min exercise bouts followed by 20 and 40 min of recovery, respectively. Cutaneous vascular conductance (CVC) was monitored at four forearm skin sites continuously perfused via intradermal microdialysis with: (1) lactated Ringer solution (Control); (2) 10 mm ascorbate (Ascorbate); (3) 10 mm l-NAME; or (4) 10 mm ascorbate + 10 mm l-NAME (Ascorbate + l

  10. Cardiorespiratory alterations induced by low-intensity exercise performed in water or on land.

    PubMed

    Ayme, Karine; Rossi, Pascal; Gavarry, Olivier; Chaumet, Guillaume; Boussuges, Alain

    2015-04-01

    The aim of this study was to compare the cardiorespiratory alterations induced by a low-intensity exercise performed on land or in water. Sixteen healthy subjects were investigated. The exercise consisted of a 1-h period of ergocycling at 35%-40% of peak oxygen uptake. Investigations were performed at rest and 45 min after the beginning of the exercises. Hemodynamic changes were studied by Doppler-echocardiography. Gas exchanges were continuously monitored by an oxygen gas analyzer. Blood samples were taken successively at baseline, within the last minutes of the exercise bout, and during recovery to measure total protein concentration and natriuretic peptides. Cardiovascular parameters were not significantly different during exercise performed on land or in water. As a result of an accelerated breathing frequency, ventilation output was significantly greater in water. Biological changes included a decrease in total protein concentration and an increase in natriuretic peptides in water. During low-intensity exercise, ventilatory alterations favoured increasing the work of breathing while in the water when compared with the same exercise performed on land. Hemodynamic changes were similar in the 2 conditions. Furthermore, biological findings suggest that the fluid transfer from intravascular sector toward interstitial sector could be facilitated in water.

  11. High-intensity interval exercise and cerebrovascular health: curiosity, cause, and consequence.

    PubMed

    Lucas, Samuel J E; Cotter, James D; Brassard, Patrice; Bailey, Damian M

    2015-06-01

    Exercise is a uniquely effective and pluripotent medicine against several noncommunicable diseases of westernised lifestyles, including protection against neurodegenerative disorders. High-intensity interval exercise training (HIT) is emerging as an effective alternative to current health-related exercise guidelines. Compared with traditional moderate-intensity continuous exercise training, HIT confers equivalent if not indeed superior metabolic, cardiac, and systemic vascular adaptation. Consequently, HIT is being promoted as a more time-efficient and practical approach to optimize health thereby reducing the burden of disease associated with physical inactivity. However, no studies to date have examined the impact of HIT on the cerebrovasculature and corresponding implications for cognitive function. This review critiques the implications of HIT for cerebrovascular function, with a focus on the mechanisms and translational impact for patient health and well-being. It also introduces similarly novel interventions currently under investigation as alternative means of accelerating exercise-induced cerebrovascular adaptation. We highlight a need for studies of the mechanisms and thereby also the optimal dose-response strategies to guide exercise prescription, and for studies to explore alternative approaches to optimize exercise outcomes in brain-related health and disease prevention. From a clinical perspective, interventions that selectively target the aging brain have the potential to prevent stroke and associated neurovascular diseases.

  12. Exercise intensities of gardening tasks within older adult allotment gardeners in Wales.

    PubMed

    Hawkins, Jemma L; Smith, Alexander; Backx, Karianne; Clayton, Deborah A

    2015-04-01

    Previous research has suggested that gardening activity could be an effective form of regular exercise for improving physical and psychological health in later life. However, there is a lack of data regarding the exercise intensities of various gardening tasks across different types of gardening and different populations. The purpose of this study was to examine the exercise intensity of gardening activity for older adult allotment gardeners in Wales, United Kingdom following a similar procedure used in previous studies conducted in the United States and South Korea by Park and colleagues (2008a; 2011). Oxygen consumption (VO2) and energy expenditure for six gardening tasks were measured via indirect calorimetery using the portable Oxycon mobile device. From these measures, estimated metabolic equivalent units (METs) were calculated. Consistent with Park et al. (2008a; 2011) the six gardening tasks were classified as low to moderate-high intensity physical activities based on their metabolic values (1.9-5.7 METs).

  13. The Effect of Vigorous Intensity Acute Exercise on Executive Function

    ERIC Educational Resources Information Center

    Phillips, David Spencer

    2012-01-01

    The effect of physical activity (PA) and consequent influence on cognition within adult seniors has been widely published. However, there is a paucity of causal research relating PA and cognition to schoolchildren within an authentic setting. Also, little is known about the required intensity and dosage of PA to effect executive function (EF)…

  14. Serum cardiac troponin I analysis to determine the excessiveness of exercise intensity: A novel equation.

    PubMed

    Voets, Philip J G M; Maas, Roderick P P W M

    2016-03-01

    Physical exertion is often promoted because of its beneficial health effects. This only holds true, however, as long as the optimal exercise intensity is not exceeded. If physical exertion becomes too strenuous or prolonged, cardiac injury or dysfunction may occur. Consequently, a significant elevation of the serum concentration of the sensitive and specific cardiac biomarker troponin I can be observed. In this article, we present the derivation of a novel equation that can be used to evaluate to what extent the intensity of conducted endurance exercise was excessive, based on a post-exercise assessment of serum cardiac troponin I. This is convenient, as exercise intensity is difficult for an athlete to quantify accurately and the currently used heart rate indices can be affected by various physiological and environmental factors. Serum cardiac troponin I, on the other hand, is a post-hoc parameter that directly reflects the actual effects on the myocardium and may therefore be a promising alternative. To our knowledge, this is the first method to determine relative exercise intensity in retrospect. We therefore believe that this equation can serve as a potentially valuable tool to objectively evaluate the benefits or harmful effects of physical exertion.

  15. Acute effects of moderate intensity aerobic exercise on affective withdrawal symptoms and cravings among women smokers.

    PubMed

    Williams, David M; Dunsiger, Shira; Whiteley, Jessica A; Ussher, Michael H; Ciccolo, Joseph T; Jennings, Ernestine G

    2011-08-01

    A growing number of laboratory studies have shown that acute bouts of aerobic exercise favorably impact affect and cravings among smokers. However, randomized trials have generally shown exercise to have no favorable effect on smoking cessation or withdrawal symptoms during quit attempts. The purpose of the present study was to explore this apparent contradiction by assessing acute changes in affect and cravings immediately prior to and following each exercise and contact control session during an eight-week smoking cessation trial. Sixty previously low-active, healthy, female smokers were randomized to an eight-week program consisting of brief baseline smoking cessation counseling and the nicotine patch plus either three sessions/week of moderate intensity aerobic exercise or contact control. Findings revealed a favorable impact of exercise on acute changes in positive activated affect (i.e., energy), negative deactivated affect (i.e., tiredness), and cigarette cravings relative to contact control. However, effects dissipated from session to session. Results suggest that aerobic exercise has potential as a smoking cessation treatment, but that it must be engaged in frequently and consistently over time in order to derive benefits. Thus, it is not surprising that previous randomized controlled trials-in which adherence to exercise programs has generally been poor-have been unsuccessful in showing effects of aerobic exercise on smoking cessation outcomes.

  16. The Metabolic Cost of a High Intensity Exercise Program During Bed Rest

    NASA Technical Reports Server (NTRS)

    Hackney, Kyle; Everett, Meghan; Guined, Jamie; Cunningham, Daid

    2012-01-01

    Background: Given that disuse-related skeletal muscle atrophy may be exacerbated by an imbalance between energy intake and output, the amount of energy required to complete exercise countermeasures is an important consideration in the well being of subject health during bed rest and spaceflight. Objective: To evaluate the energy cost of a high intensity exercise program performed during short duration bed rest. Methods: 9 subjects (8 male and 1 female; 34.5 +/- 8.2 years) underwent 14 days of bed rest and exercise countermeasures. Exercise energy expenditure and excess post exercise oxygen consumption (EPOC) were collected once in each of 5 different exercise protocols (30 second, 2 minute and 4 minute intervals, continuous aerobic and a variety of resistance exercises) during bed rest. Body mass, basal metabolic rate (BMR), upper and lower leg muscle, subcutaneous, and intramuscular adipose tissue (IMAT) volumes were assessed before and at the end of bed rest. Results: There were no significant differences in body mass (pre: 75.1 +/- 10.5 kg; post: 75.2 +/- 10.1 kg), BMR (pre: 1649 +/- 216 kcal; post: 1657 +/- 177 kcal), muscle subcutaneous, or IMAT volumes (Table 2) after 14 days of bed rest and exercise. Body mass was maintained with an average daily intake of 2710 +/- 262 kcal (36.2 +/- 2.1 kcal/kg/day), while average daily energy expenditure was 2579 +/-311 kcal (34.5 +/- 3.6 kcal/kg/day). Exercise energy expenditure was significantly greater as a result of continuous aerobic exercise than all other exercise protocols.

  17. Effects of Exercise Intensity on Postprandial Improvement in Glucose Disposal and Insulin Sensitivity in Prediabetic Adults

    PubMed Central

    Rynders, Corey A.; Weltman, Judy Y.; Jiang, Boyi; Breton, Marc; Patrie, James; Barrett, Eugene J.

    2014-01-01

    Background: A single bout of exercise improves postprandial glycemia and insulin sensitivity in prediabetic patients; however, the impact of exercise intensity is not well understood. The present study compared the effects of acute isocaloric moderate (MIE) and high-intensity (HIE) exercise on glucose disposal and insulin sensitivity in prediabetic adults. Methods: Subjects (n = 18; age 49 ± 14 y; fasting glucose 105 ± 11 mg/dL; 2 h glucose 170 ± 32 mg/dL) completed a peak O2 consumption/lactate threshold (LT) protocol plus three randomly assigned conditions: 1) control, 1 hour of seated rest, 2) MIE (at LT), and 3) HIE (75% of difference between LT and peak O2 consumption). One hour after exercise, subjects received an oral glucose tolerance test (OGTT). Plasma glucose, insulin, and C-peptide concentrations were sampled at 5- to 10-minute intervals at baseline, during exercise, after exercise, and for 3 hours after glucose ingestion. Total, early-phase, and late-phase area under the glucose and insulin response curves were compared between conditions. Indices of insulin sensitivity (SI) were derived from OGTT data using the oral minimal model. Results: Compared with control, SI improved by 51% (P = .02) and 85% (P < .001) on the MIE and HIE days, respectively. No differences in SI were observed between the exercise conditions (P = .62). Improvements in SI corresponded to significant reductions in the glucose, insulin, and C-peptide area under the curve values during the late phase of the OGTT after HIE (P < .05), with only a trend for reductions after MIE. Conclusion: These results suggest that in prediabetic adults, acute exercise has an immediate and intensity-dependent effect on improving postprandial glycemia and insulin sensitivity. PMID:24243632

  18. Left ventricular mechanics and arterial-ventricular coupling following high-intensity interval exercise.

    PubMed

    Cote, Anita T; Bredin, Shannon S D; Phillips, Aaron A; Koehle, Michael S; Glier, Melissa B; Devlin, Angela M; Warburton, Darren E R

    2013-12-01

    High-intensity exercise induces marked physiological stress affecting the secretion of catecholamines. Sustained elevations in catecholamines are thought to desensitize cardiac beta receptors and may be a possible mechanism in impaired cardiac function following strenuous exercise. In addition, attenuated arterial-ventricular coupling may identify vascular mechanisms in connection with postexercise attenuations in ventricular function. Thirty-nine normally active (NA) and endurance-trained (ET) men and women completed an echocardiographic evaluation of left ventricular function before and after an acute bout of high-intensity interval exercise (15 bouts of 1:2 min work:recovery cycling: 100% peak power output and 50 W, respectively). Following exercise, time to peak twist and peak untwisting velocity were delayed (P < 0.01) but did not differ by sex or training status. Interactions for sex and condition (rest vs. exercise) were found for longitudinal diastolic strain rate (men, 1.46 ± 0.19 to 1.28 ± 0.23 s(-1) vs. women, 1.62 ± 0.25 to 1.63 ± 0.26 s(-1); P = 0.01) and arterial elastance (men 2.20 ± 0.65 to 3.24 ± 1.02 mmHg · ml(-1) · m(-2) vs. women 2.51 ± 0.61 to 2.93 ± 0.68 mmHg · ml(-1) · m(-2); P = 0.04). No cardiac variables were found associated with catecholamine levels. The change in twist mechanics was associated with baseline aortic pulse-wave velocity (r(2) = 0.27, P = 0.001). We conclude that males display greater reductions in contractility in response to high-intensity interval exercise, independent of catecholamine concentrations. Furthermore, a novel association of arterial stiffness and twist mechanics following high-intensity acute exercise illustrates the influence of vascular integrity on cardiac mechanics.

  19. Decreasing Power Output Increases Aerobic Contribution During Low-Volume Severe-Intensity Intermittent Exercise.

    PubMed

    Lisbôa, Felipe D; Salvador, Amadeo F; Raimundo, João A G; Pereira, Kayo L; de Aguiar, Rafael A; Caputo, Fabrizio

    2015-09-01

    High-intensity interval training applied at submaximal, maximal, and supramaximal intensities for exercising at V[Combining Dot Above]O2max (t95V[Combining Dot Above]O2max) has shown similar adaptation to low-volume sprint interval training among active subjects. Thus, the aim of the present study was to investigate t95V[Combining Dot Above]O2max during 2 different intermittent exercises in the severe-intensity domain (e.g., range of power outputs over which V[Combining Dot Above]O2max can be elicited during constant-load exercise) and to identify an exercise protocol that reduces the time required to promote higher aerobic demand. Eight active men (22 ± 2 years, 72 ± 5 kg, 174 ± 4 cm, 47 ± 8 ml·kg·min) completed the following protocols on a cycle ergometer: (a) incremental test, (b) determination of critical power (CP), (c) determination of the highest constant intensity (IHIGH) and the lowest exercise duration (TLOW) in which V[Combining Dot Above]O2max is attained, and (d) 2 exercise sessions in a randomized order that consisted of a constant power output (CPO) session at IHIGH and a decreasing power output (DPO) session that applied a decreasing work rate profile from IHIGH to 110% of CP. Time to exhaustion was significantly longer in DPO (371 ± 57 seconds vs. 225 ± 33 seconds). Moreover, t95V[Combining Dot Above]O2max (186 ± 72 seconds vs. 76 ± 49 seconds) and O2 consumed (29 ± 4 L vs. 17 ± 3 L) were higher in DPO when compared with the CPO protocol. In conclusion, data suggest that the application of a DPO protocol during intermittent exercise increases the time spent at high percentages of V[Combining Dot Above]O2max.

  20. Comparing Fat Oxidation in an Exercise Test with Moderate-Intensity Interval Training

    PubMed Central

    Alkahtani, Shaea

    2014-01-01

    This study compared fat oxidation rate from a graded exercise test (GXT) with a moderate-intensity interval training session (MIIT) in obese men. Twelve sedentary obese males (age 29 ± 4.1 years; BMI 29.1 ± 2.4 kg·m-2; fat mass 31.7 ± 4.4 %body mass) completed two exercise sessions: GXT to determine maximal fat oxidation (MFO) and maximal aerobic power (VO2max), and an interval cycling session during which respiratory gases were measured. The 30-min MIIT involved 5-min repetitions of workloads 20% below and 20% above the MFO intensity. VO2max was 31.8 ± 5.5 ml·kg-1·min-1 and all participants achieved ≥ 3 of the designated VO2max test criteria. The MFO identified during the GXT was not significantly different compared with the average fat oxidation rate in the MIIT session. During the MIIT session, fat oxidation rate increased with time; the highest rate (0.18 ± 0.11 g·min- 1) in minute 25 was significantly higher than the rate at minute 5 and 15 (p ≤ 0.01 and 0.05 respectively). In this cohort with low aerobic fitness, fat oxidation during the MIIT session was comparable with the MFO determined during a GXT. Future research may consider if the varying workload in moderate-intensity interval training helps adherence to exercise without compromising fat oxidation. Key Points Fat oxidation during interval exercise is not com-promised by the undulating exercise intensity Physiological measures corresponding with the MFO measured during the GXT correlated well to the MIIT The validity of exercise intensity markers derived from a GXT to reflect the physiological responses during MIIT. PMID:24570605

  1. Comparing fat oxidation in an exercise test with moderate-intensity interval training.

    PubMed

    Alkahtani, Shaea

    2014-01-01

    This study compared fat oxidation rate from a graded exercise test (GXT) with a moderate-intensity interval training session (MIIT) in obese men. Twelve sedentary obese males (age 29 ± 4.1 years; BMI 29.1 ± 2.4 kg·m(-2); fat mass 31.7 ± 4.4 %body mass) completed two exercise sessions: GXT to determine maximal fat oxidation (MFO) and maximal aerobic power (VO2max), and an interval cycling session during which respiratory gases were measured. The 30-min MIIT involved 5-min repetitions of workloads 20% below and 20% above the MFO intensity. VO2max was 31.8 ± 5.5 ml·kg(-1)·min(-1) and all participants achieved ≥ 3 of the designated VO2max test criteria. The MFO identified during the GXT was not significantly different compared with the average fat oxidation rate in the MIIT session. During the MIIT session, fat oxidation rate increased with time; the highest rate (0.18 ± 0.11 g·min(- 1)) in minute 25 was significantly higher than the rate at minute 5 and 15 (p ≤ 0.01 and 0.05 respectively). In this cohort with low aerobic fitness, fat oxidation during the MIIT session was comparable with the MFO determined during a GXT. Future research may consider if the varying workload in moderate-intensity interval training helps adherence to exercise without compromising fat oxidation. Key PointsFat oxidation during interval exercise is not com-promised by the undulating exercise intensityPhysiological measures corresponding with the MFO measured during the GXT correlated well to the MIITThe validity of exercise intensity markers derived from a GXT to reflect the physiological responses during MIIT.

  2. Differential effects of exercise intensities in hippocampal BDNF, inflammatory cytokines and cell proliferation in rats during the postnatal brain development.

    PubMed

    de Almeida, Alexandre Aparecido; Gomes da Silva, Sérgio; Fernandes, Jansen; Peixinho-Pena, Luiz Fernando; Scorza, Fulvio Alexandre; Cavalheiro, Esper Abrão; Arida, Ricardo Mario

    2013-10-11

    It has been established that low intensities of exercise produce beneficial effects for the brain, while high intensities can cause some neuronal damage (e.g. exacerbated inflammatory response and cell death). Although these effects are documented in the mature brain, the influence of exercise intensities in the developing brain has been poorly explored. To investigate the impact of exercise intensity in developing rats, we evaluated the hippocampal level of brain derived neurotrophic factor (BDNF), inflammatory cytokines (TNFα, IL6 and IL10) and the occurrence of hippocampal cell degeneration and proliferation at different stages of postnatal brain development of rats submitted to two physical exercise intensities. To this point, male rats were divided into different age groups: P21, P31, P41 and P51. Each age group was submitted to two exercise intensities (low and high) on a treadmill over 10 consecutive days, except the control rats. We verified that the density of proliferating cells was significantly higher in the dentate gyrus of rats submitted to low-intensity exercise from P21 to P30 compared with high-intensity exercise and control rats. A significant increase of proliferative cell density was found in rats submitted to high-intensity exercise from P31 to P40 when compared to low-intensity exercise and control rats. Elevated hippocampal levels of IL6 were detected in rats submitted to high-intensity exercise from P21 to P30 compared to control rats. From P41 to P50 period, higher levels of BDNF, TNFα and IL10 were found in the hippocampal formation of rats submitted to high-intensity exercise in relation to their control rats. Our data show that exercise-induced neuroplastic effects on BDNF levels and cellular proliferation in the hippocampal region are dependent on exercise intensity and developmental period. Thus, exercise intensity is an inflammation-inducing factor and exercise-induced inflammatory response during the postnatal brain development is

  3. Similar Anti-Inflammatory Acute Responses from Moderate-Intensity Continuous and High-Intensity Intermittent Exercise

    PubMed Central

    Cabral-Santos, Carolina; Gerosa-Neto, José; Inoue, Daniela Sayuri; Panissa, Valéria Leme Gonçalves; Gobbo, Luís Alberto; Zagatto, Alessandro Moura; Campos, Eduardo Zapaterra; Lira, Fábio Santos

    2015-01-01

    The purpose of this study was to compare the effect of high-intensity intermittent exercise (HIIE) versus volume matched steady state exercise (SSE) on inflammatory and metabolic responses. Eight physically active male subjects completed two experimental sessions, a 5-km run on a treadmill either continuously (70% vVO2max) or intermittently (1:1 min at vVO2max). Blood samples were collected at rest, immediately, 30 and 60 minutes after the exercise session. Blood was analyzed for glucose, non-ester fatty acid (NEFA), uric acid, lactate, cortisol, and cytokines (IL-6, IL-10 and TNF-α) levels. The lactate levels exhibited higher values immediately post-exercise than at rest (HIIE 1.34 ± 0.24 to 7.11 ± 2.85, and SSE 1.35 ± 0.14 to 4.06±1.60 mmol·L-1, p < 0.05), but HIIE promoted higher values than SSE (p < 0.05); the NEFA levels were higher immediately post-exercise than at rest only in the SSE condition (0.71 ± 0.04 to 0.82±0.09 mEq/L, respectively, p < 0.05), yet, SSE promoted higher values than HIIE immediately after exercise (HIIE 0.72±0.03 vs SSE 0.82±0.09 mEq·L-1, p < 0.05). Glucose and uric acid levels did not show changes under the different conditions (p > 0.05). Cortisol, IL-6, IL-10 and TNF-α levels showed time-dependent changes under the different conditions (p < 0.05), however, the area under the curve of TNF-α in the SSE were higher than HIIE (p < 0.05), and the area under the curve of IL-6 in the HIIE showed higher values than SSE (p < 0.05). In addition, both exercise conditions promote increased IL-10 levels and IL-10/TNF-α ratio (p < 0.05). In conclusion, our results demonstrated that both exercise protocols, when volume is matched, promote similar inflammatory responses, leading to an anti-inflammatory status; however, the metabolic responses are different. Key points Metabolic contribution of both exercise, HIIE and SSE, was different. Both protocols leading to an anti-inflammatory status. HIIE induce a higher energy expenditure take

  4. Regulation of glycogen synthase and phosphorylase during recovery from high-intensity exercise in the rat.

    PubMed Central

    Bräu, L; Ferreira, L D; Nikolovski, S; Raja, G; Palmer, T N; Fournier, P A

    1997-01-01

    The aim of this study was to determine the role of the phosphorylation state of glycogen synthase and glycogen phosphorylase in the regulation of muscle glycogen repletion in fasted animals recovering from high-intensity exercise. Groups of rats were swum to exhaustion and allowed to recover for up to 120 min without access to food. Swimming to exhaustion caused substantial glycogen breakdown and lactate accumulation in the red, white and mixed gastrocnemius muscles, whereas the glycogen content in the soleus muscle remained stable. During the first 40 min of recovery, significant repletion of glycogen occurred in all muscles examined except the soleus muscle. At the onset of recovery, the activity ratios and fractional velocities of glycogen synthase in the red, white and mixed gastrocnemius muscles were higher than basal, but returned to pre-exercise levels within 20 min after exercise. In contrast, after exercise the activity ratios of glycogen phosphorylase in the same muscles were lower than basal, and increased to pre-exercise levels within 20 min. This pattern of changes in glycogen synthase and phosphorylase activities, never reported before, suggests that the integrated regulation of the phosphorylation state of both glycogen synthase and phosphorylase might be involved in the control of glycogen deposition after high-intensity exercise. PMID:9078277

  5. Effect of high-intensity exercise on aged mouse brain mitochondria, neurogenesis, and inflammation.

    PubMed

    E, Lezi; Burns, Jeffrey M; Swerdlow, Russell H

    2014-11-01

    In aged mice, we assessed how intensive exercise affects brain bioenergetics, inflammation, and neurogenesis-relevant parameters. After 8 weeks of a supra-lactate threshold treadmill exercise intervention, 21-month-old C57BL/6 mice showed increased brain peroxisome proliferator-activated receptor gamma coactivator-1α protein, mammalian target of rapamycin and phospho-mammalian target of rapamycin protein, citrate synthase messenger RNA, and mitochondrial DNA copy number. Hippocampal vascular endothelial growth factor A (VEGF-A) gene expression trended higher, and a positive correlation between VEGF-A and PRC messenger RNA levels was observed. Brain doublecortin, brain-derived neurotrophic factor, tumor necrosis factor-α, and CCL11 gene expression, as well as plasma CCL11 protein levels, were unchanged. Despite these apparent negative findings, a negative correlation between plasma CCL11 protein levels and hippocampal doublecortin gene expression was observed; further analysis indicated exercise may mitigate this relationship. Overall, our data suggest supra-lactate threshold exercise activates a partial mitochondrial biogenesis in aged mice, and a gene (VEGF-A) known to support neurogenesis. Our data are consistent with another study that found systemic inflammation in general, and CCL11 protein specifically, suppresses hippocampal neurogenesis. Our study supports the view that intense exercise above the lactate threshold may benefit the aging brain; future studies to address the extent to which exercise-generated lactate mediates the observed effects are warranted.

  6. Vertical ground reaction force during water exercises performed at different intensities.

    PubMed

    Alberton, C L; Tartaruga, M P; Pinto, S S; Cadore, E L; Antunes, A H; Finatto, P; Kruel, L F M

    2013-10-01

    The aim of the present study was to compare the peak vertical ground reaction force (V-GRF(peak)) and impulse of women performing water aerobic exercises at different intensities in aquatic and dry land environments. 15 young women performed 1 session in each environment consisting of 3 water aerobic exercises (stationary running, frontal kick and cross country skiing) performed at 3 cadences (first ventilatory threshold, second ventilatory threshold and maximum effort, as determined during exercise in water) in a randomized order. 2-way and 3-way repeated measures ANOVA were used to analyze the impulse and V-GRF(peak), respectively. Significantly lower values of V-GRF(peak) and impulse (p<0.001) were observed for the aquatic environment. Significant differences were observed among all cadences for V-GRF(peak) and impulse (p<0.001) in both environments except for the V-GRF(peak) between the cadences corresponding to the second ventilatory threshold and maximum effort in the aquatic environment. In addition, significantly lower V-GRF(peak) values in the aquatic environment were found for cross country skiing compared to the other exercises (p<0.001). Thus, water exercises are safe for people that need to minimize vertical ground reaction force; however, an important issue to be considered during water aerobics training is the exercise and intensity to be prescribed.

  7. Analog Exercise Hardware to Implement a High Intensity Exercise Program During Bed Rest

    NASA Astrophysics Data System (ADS)

    Loerch, Linda; Newby, Nate; Sinka, Joe; Ploutz-Snyder, Lori

    2013-02-01

    To evaluate novel countermeasure protocols in a spaceflight analog setting before validation on the International Space Station, NASA’s Human Research Program is sponsoring a multi-investigator bed rest campaign that uses a combination of commercial and custom-made exercise training hardware to conduct daily resistance and aerobic exercise protocols. These devices include the stand alone zero-gravity locomotion simulator, horizontal squat device, Lode commercial supine cycle ergometer, Cybex commercial prone leg curl machine, and Quantum Fitness commercial horizontal leg press. This paper will describe these pieces of hardware that are used to support current bed rest studies at NASA’s Flight Analog Research Unit in Galveston, Texas, USA.

  8. Influence of repeated bouts of eccentric exercise on high-intensity aerobic performance

    PubMed Central

    Higino, Wonder Passoni; Aparecido de Souza, Renato; Cavalcanti, Fabio de Sousa; Cardoso, Anderlei dos Santos; Vasconcelos, Murilo Victor; Fernandes da Silva, Fabiano; Leme, José Alexandre C.A.

    2016-01-01

    [Purpose] It is believed that eccentric high-intensity exercise can decrease performance in subsequent exercise. However, with repetition, the deleterious effects can be minimized. Thus, this study evaluated the influence of repeated bouts of eccentric exercise on subsequent high-intensity aerobic performance. [Subjects and Methods] Seven healthy and sedentary male volunteers were recruited. a) Visit 1: determination of maximum oxygen uptake (VO2max) and speed associated with maximum oxygen uptake (vVO2max) in incremental treadmill testing; b) Visit 2: run to exhaustion at vVO2max (Tlim control); c) Visit 3: 10 sets of 10 depth jumps, followed by a run to exhaustion at vVO2max (Tlim 1); d) Visit 4: after 6 weeks without any physical training, the volunteers carried out the same procedures as on the third visit (Tlim 2). Data were analyzed using one-way analysis of variance (ANOVA) with the post-hoc Tukey test. [Results] Significant differences were found between Tlim control and Tlim 1 (283.4 ± 47.7 s vs. 125.2 ± 64.1 s, respectively), these were not different from Tlim 2. [Conclusion] Eccentric exercise showed deleterious effects on subsequent high-intensity aerobic performance. These effects were minimized after the exercise protocol was repeated 6 weeks after the first event.

  9. Influence of repeated bouts of eccentric exercise on high-intensity aerobic performance.

    PubMed

    Higino, Wonder Passoni; Aparecido de Souza, Renato; Cavalcanti, Fabio de Sousa; Cardoso, Anderlei Dos Santos; Vasconcelos, Murilo Victor; Fernandes da Silva, Fabiano; Leme, José Alexandre C A

    2016-08-01

    [Purpose] It is believed that eccentric high-intensity exercise can decrease performance in subsequent exercise. However, with repetition, the deleterious effects can be minimized. Thus, this study evaluated the influence of repeated bouts of eccentric exercise on subsequent high-intensity aerobic performance. [Subjects and Methods] Seven healthy and sedentary male volunteers were recruited. a) Visit 1: determination of maximum oxygen uptake (VO2max) and speed associated with maximum oxygen uptake (vVO2max) in incremental treadmill testing; b) Visit 2: run to exhaustion at vVO2max (Tlim control); c) Visit 3: 10 sets of 10 depth jumps, followed by a run to exhaustion at vVO2max (Tlim 1); d) Visit 4: after 6 weeks without any physical training, the volunteers carried out the same procedures as on the third visit (Tlim 2). Data were analyzed using one-way analysis of variance (ANOVA) with the post-hoc Tukey test. [Results] Significant differences were found between Tlim control and Tlim 1 (283.4 ± 47.7 s vs. 125.2 ± 64.1 s, respectively), these were not different from Tlim 2. [Conclusion] Eccentric exercise showed deleterious effects on subsequent high-intensity aerobic performance. These effects were minimized after the exercise protocol was repeated 6 weeks after the first event.

  10. Postprandial lipoprotein profile in two modes of high-intensity intermittent exercise

    PubMed Central

    Panissa, Valéria Leme Gonçalves; Julio, Ursula Ferreira; Diniz, Tiego Aparecido; de Moura Mello Antunes, Barbara; Lira, Fabio Santos; Takito, Monica Yuri; Franchini, Emerson

    2016-01-01

    The aim of present study was to compare blood lipid postprandial profile response in two modes of high-intensity intermittent exercise. Twelve individuals (6 men and 6 women) were submitted to a maximal incremental test (to determine maximal aerobic power [MAP] and V. O2peak [peak oxygen uptake]), high-intensity intermittent all-out exercise (60×8-sec bouts interspersed by 12-sec passive recovery) and fixed high-intensity intermittent exercise (100% maximal aerobic speed, consisted of 1-min repetitions at MAP [70 rpm] separated by 1-min of passive recovery). Blood samples were collected pre, immediately, 45 and 90-min postexercise. Serum was analyzed for total cholesterol and its ratio, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), very low-density lipoprotein (VLDL) cholesterol, and triacylglycerol (TAG). For TAG there was a main effect of moment with higher values immediately postexercise compared to 45-min postexercise. For VLDL there was a main effect to moment with higher values immediately post exercise than pre and 45-min postexercise; higher values 90-min postexercise than 45-min postexercise. There was no effect for HDL-c, LDL-c, and cholesterol. For area under the curve there was no difference for any variable. Our results indicated that both kinds of acute exercise session lead to no improvement in the acute response of serum lipid profile of healthy young. PMID:27807528

  11. Influence of repeated bouts of eccentric exercise on high-intensity aerobic performance.

    PubMed

    Higino, Wonder Passoni; Aparecido de Souza, Renato; Cavalcanti, Fabio de Sousa; Cardoso, Anderlei Dos Santos; Vasconcelos, Murilo Victor; Fernandes da Silva, Fabiano; Leme, José Alexandre C A

    2016-08-01

    [Purpose] It is believed that eccentric high-intensity exercise can decrease performance in subsequent exercise. However, with repetition, the deleterious effects can be minimized. Thus, this study evaluated the influence of repeated bouts of eccentric exercise on subsequent high-intensity aerobic performance. [Subjects and Methods] Seven healthy and sedentary male volunteers were recruited. a) Visit 1: determination of maximum oxygen uptake (VO2max) and speed associated with maximum oxygen uptake (vVO2max) in incremental treadmill testing; b) Visit 2: run to exhaustion at vVO2max (Tlim control); c) Visit 3: 10 sets of 10 depth jumps, followed by a run to exhaustion at vVO2max (Tlim 1); d) Visit 4: after 6 weeks without any physical training, the volunteers carried out the same procedures as on the third visit (Tlim 2). Data were analyzed using one-way analysis of variance (ANOVA) with the post-hoc Tukey test. [Results] Significant differences were found between Tlim control and Tlim 1 (283.4 ± 47.7 s vs. 125.2 ± 64.1 s, respectively), these were not different from Tlim 2. [Conclusion] Eccentric exercise showed deleterious effects on subsequent high-intensity aerobic performance. These effects were minimized after the exercise protocol was repeated 6 weeks after the first event. PMID:27630434

  12. Influence of repeated bouts of eccentric exercise on high-intensity aerobic performance

    PubMed Central

    Higino, Wonder Passoni; Aparecido de Souza, Renato; Cavalcanti, Fabio de Sousa; Cardoso, Anderlei dos Santos; Vasconcelos, Murilo Victor; Fernandes da Silva, Fabiano; Leme, José Alexandre C.A.

    2016-01-01

    [Purpose] It is believed that eccentric high-intensity exercise can decrease performance in subsequent exercise. However, with repetition, the deleterious effects can be minimized. Thus, this study evaluated the influence of repeated bouts of eccentric exercise on subsequent high-intensity aerobic performance. [Subjects and Methods] Seven healthy and sedentary male volunteers were recruited. a) Visit 1: determination of maximum oxygen uptake (VO2max) and speed associated with maximum oxygen uptake (vVO2max) in incremental treadmill testing; b) Visit 2: run to exhaustion at vVO2max (Tlim control); c) Visit 3: 10 sets of 10 depth jumps, followed by a run to exhaustion at vVO2max (Tlim 1); d) Visit 4: after 6 weeks without any physical training, the volunteers carried out the same procedures as on the third visit (Tlim 2). Data were analyzed using one-way analysis of variance (ANOVA) with the post-hoc Tukey test. [Results] Significant differences were found between Tlim control and Tlim 1 (283.4 ± 47.7 s vs. 125.2 ± 64.1 s, respectively), these were not different from Tlim 2. [Conclusion] Eccentric exercise showed deleterious effects on subsequent high-intensity aerobic performance. These effects were minimized after the exercise protocol was repeated 6 weeks after the first event. PMID:27630434

  13. Absolute geomagnetic intensity determinations on Formative potsherds (1400-700 BC) from the Oaxaca Valley, Southwestern Mexico

    NASA Astrophysics Data System (ADS)

    Pétronille, Marie; Goguitchaichvili, Avto; Morales, Juan; Carvallo, Claire; Hueda-Tanabe, Yuki

    2012-11-01

    New Thellier-Coe archeointensity determinations have been measured on 15 potsherds from the Oaxaca Valley belonging to three of the four Formative Periods (Pre-Classical) of Mesoamerica, spanning 1400-700 BC. Seven of these are considered to be reliable and indicate a geomagnetic field strength of about 30 μT. This value is some 75% of the present geomagnetic field strength but is in agreement with the absolute intensities predicted from global models for this time and location, and consistent with coeval published determinations. These data thus provide significant evidence for the geomagnetic field strength in an area and for a time that was previously poorly constrained, thus providing an important contribution towards establishing a local master curve for the last 3500 yr. When established, such a curve would be a useful dating tool and also enable establishing for field strength correlations with climatic events and civilization evolutions in a region that is particularly strong in archeological and geological features. Such potential is examined for aridity events, although such observations can only be considered tentative at this stage.

  14. 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.…

  15. Movement velocity as a measure of exercise intensity in three lower limb exercises.

    PubMed

    Conceição, Filipe; Fernandes, Juvenal; Lewis, Martin; Gonzaléz-Badillo, Juan José; Jimenéz-Reyes, Pedro

    2016-01-01

    The purpose of this study was to investigate the relationship between movement velocity and relative load in three lower limbs exercises commonly used to develop strength: leg press, full squat and half squat. The percentage of one repetition maximum (%1RM) has typically been used as the main parameter to control resistance training; however, more recent research has proposed movement velocity as an alternative. Fifteen participants performed a load progression with a range of loads until they reached their 1RM. Maximum instantaneous velocity (Vmax) and mean propulsive velocity (MPV) of the knee extension phase of each exercise were assessed. For all exercises, a strong relationship between Vmax and the %1RM was found: leg press (r(2)adj = 0.96; 95% CI for slope is [-0.0244, -0.0258], P < 0.0001), full squat (r(2)adj = 0.94; 95% CI for slope is [-0.0144, -0.0139], P < 0.0001) and half squat (r(2)adj = 0.97; 95% CI for slope is [-0.0135, -0.00143], P < 0.0001); for MPV, leg press (r(2)adj = 0.96; 95% CI for slope is [-0.0169, -0.0175], P < 0.0001, full squat (r(2)adj = 0.95; 95% CI for slope is [-0.0136, -0.0128], P < 0.0001) and half squat (r(2)adj = 0.96; 95% CI for slope is [-0.0116, 0.0124], P < 0.0001). The 1RM was attained with a MPV and Vmax of 0.21 ± 0.06 m s(-1) and 0.63 ± 0.15 m s(-1), 0.29 ± 0.05 m s(-1) and 0.89 ± 0.17 m s(-1), 0.33 ± 0.05 m s(-1) and 0.95 ± 0.13 m s(-1) for leg press, full squat and half squat, respectively. Results indicate that it is possible to determine an exercise-specific %1RM by measuring movement velocity for that exercise. PMID:26395837

  16. Movement velocity as a measure of exercise intensity in three lower limb exercises.

    PubMed

    Conceição, Filipe; Fernandes, Juvenal; Lewis, Martin; Gonzaléz-Badillo, Juan José; Jimenéz-Reyes, Pedro

    2016-01-01

    The purpose of this study was to investigate the relationship between movement velocity and relative load in three lower limbs exercises commonly used to develop strength: leg press, full squat and half squat. The percentage of one repetition maximum (%1RM) has typically been used as the main parameter to control resistance training; however, more recent research has proposed movement velocity as an alternative. Fifteen participants performed a load progression with a range of loads until they reached their 1RM. Maximum instantaneous velocity (Vmax) and mean propulsive velocity (MPV) of the knee extension phase of each exercise were assessed. For all exercises, a strong relationship between Vmax and the %1RM was found: leg press (r(2)adj = 0.96; 95% CI for slope is [-0.0244, -0.0258], P < 0.0001), full squat (r(2)adj = 0.94; 95% CI for slope is [-0.0144, -0.0139], P < 0.0001) and half squat (r(2)adj = 0.97; 95% CI for slope is [-0.0135, -0.00143], P < 0.0001); for MPV, leg press (r(2)adj = 0.96; 95% CI for slope is [-0.0169, -0.0175], P < 0.0001, full squat (r(2)adj = 0.95; 95% CI for slope is [-0.0136, -0.0128], P < 0.0001) and half squat (r(2)adj = 0.96; 95% CI for slope is [-0.0116, 0.0124], P < 0.0001). The 1RM was attained with a MPV and Vmax of 0.21 ± 0.06 m s(-1) and 0.63 ± 0.15 m s(-1), 0.29 ± 0.05 m s(-1) and 0.89 ± 0.17 m s(-1), 0.33 ± 0.05 m s(-1) and 0.95 ± 0.13 m s(-1) for leg press, full squat and half squat, respectively. Results indicate that it is possible to determine an exercise-specific %1RM by measuring movement velocity for that exercise.

  17. Activation of autophagy in human skeletal muscle is dependent on exercise intensity and AMPK activation.

    PubMed

    Schwalm, Céline; Jamart, Cécile; Benoit, Nicolas; Naslain, Damien; Prémont, Christophe; Prévet, Jérémy; Van Thienen, Ruud; Deldicque, Louise; Francaux, Marc

    2015-08-01

    In humans, nutrient deprivation and extreme endurance exercise both activate autophagy. We hypothesized that cumulating fasting and cycling exercise would potentiate activation of autophagy in skeletal muscle. Well-trained athletes were divided into control (n = 8), low-intensity (LI, n = 8), and high-intensity (HI, n = 7) exercise groups and submitted to fed and fasting sessions. Muscle biopsy samples were obtained from the vastus lateralis before, at the end, and 1 h after a 2 h LI or HI bout of exercise. Phosphorylation of ULK1(Ser317) was higher after exercise (P < 0.001). In both the fed and the fasted states, LC3bII protein level and LC3bII/I were decreased after LI and HI (P < 0.05), while p62/SQSTM1 was decreased only 1 h after HI (P < 0.05), indicating an increased autophagic flux after HI. The autophagic transcriptional program was also activated, as evidenced by the increased level of LC3b, p62/SQSTM1, GabarapL1, and Cathepsin L mRNAs observed after HI but not after LI. The increased autophagic flux after HI exercise could be due to increased AMP-activated protein kinase α (AMPKα) activity, as both AMPKα(Thr172) and ACC(Ser79) had a higher phosphorylation state after HI (P < 0.001). In summary, the most effective strategy to activate autophagy in human skeletal muscle seems to rely on exercise intensity more than diet. PMID:25957282

  18. Effect of Exercise Intensity on Differentiated and Undifferentiated Ratings of Perceived Exertion During Cycle and Treadmill Exercise in Recreationally Active and Trained Women

    PubMed Central

    Bolgar, Melinda R.; Baker, Carol E.; Goss, Fredric. L.; Nagle, Elizabeth; Robertson, Robert J.

    2010-01-01

    The purpose of the study is to examine the effect of aerobic exercise intensity on components of the differentiated perceived exertion model in young women performing weight bearing and non-weight bearing aerobic exercise. Subjects were 18-25 yr old women who were recreationally active (n = 19; VO2max = 33.40 ml·kg-1·min-1) and trained (N = 22; VO2max = 43.3 ml·kg-1·min-1). Subjects underwent two graded exercise tests (GXT) on a treadmill and bike which were separated by 48 hours. RPE-Overall, -Legs, and -Chest, as well as oxygen uptake (VO2) and heart rate were recorded each minute. Individual regression analyses were used to identify RPE-Overall,-Legs, and -Chest at 40, 60, 80% VO2max/peak. Separate two factor (site (3) x intensity (3)) ANOVAs with repeated measures on site and intensity were computed for each training status. Furthermore, RPE responses were also examined with a one factor (site (3)) within subject ANOVA with repeated measure on site at the ventilatory breakpoint. For both the recreationally active and trained groups no significant differences were observed for RPE-Overall, -Legs, and -Chest during treadmill exercise. However, for cycling exercise results indicated that RPE-Legs was significantly greater at all exercise intensities than RPE-Overall and RPE-Chest for trained subjects while for recreationally active subjects RPE-Legs was only significantly higher at the highest exercise intensity. Responses at the ventilatory breakpoint during cycle exercise indicated that RPE-Legs was significantly greater than RPE-Chest and RPE-Overall for trained subjects but not for recreationally active subjects. Signal dominance was not observed at an intensity equivalent to the ventilatory breakpoint during treadmill exercise in either of the groups. In recreationally active and trained females signal dominance was demonstrated only during cycling exercise, but not during treadmill exercise. Signal integration could not be demonstrated during cycling and

  19. Joint Cooling does not Hinder Athletic Performance during High-intensity Intermittent Exercise.

    PubMed

    Kim, H; Lee, D; Choi, H-M; Park, J

    2016-07-01

    We examined the effects of ankle and knee joint cooling on 20-m sprint times and maximal vertical jump heights during high-intensity intermittent exercise. 21 healthy collegiate male basketball (n=14) and handball players (n=7) underwent 3 experimental sessions. Each session consisted of four 15-min quarters of high-intensity intermittent exercises including various intensities of 20-m shuttle running and jumping. A 20-min bilateral joint cooling (ankle, knee, or control-no cooling: in a counterbalanced order) was applied before quarters 1 and 3. After joint cooling, no warm-up activity other than the exercise protocol was given. The 20-m sprint times and maximal vertical jump heights in each experimental session were recorded at baseline (prior to quarter-1) and during each quarter. To test joint cooling effects over time, we performed 3×5 mixed model ANOVAs. Neither ankle nor knee joint cooling changed 20-m sprint times (F8,280=1.45; p=0.18) or maximal vertical jump heights (F8,280=0.76; p=0.64). However, a trend was observed in which joint cooling immediately decreased (quarters 1 and 3) but active warm-up for approximately 20 min improved 20-min sprint times (quarters 2 and 4). Our study suggests that athletic performance such as sprinting and jumping are not altered by joint cooling applied prior to or during high-intensity intermittent exercise. PMID:27119166

  20. Exercise intensity and gender difference of 3 different salsa dancing conditions.

    PubMed

    Emerenziani, G P; Guidetti, L; Gallotta, M C; Franciosi, E; Buzzachera, C F; Baldari, C

    2013-04-01

    The aims of this study were to estimate the difference in exercise intensity (METs), energy cost (EE) and gender difference between a typical salsa lesson (TSL), rueda de casino lesson (RCL), and salsa dancing at a night club (SDN). Subjects performed 1 pre-testing session and 3 testing conditions. During the pre-testing session height, weight and V˙O2max were assessed. During the testing conditions all subjects performed 3 different kinds of salsa dance. Heart rate was assessed during each dance condition. The exercise intensity of the 3 salsa dancing conditions was moderate ranging from 3.9 to 5.5 METs. A significant difference between genders for HRpeak (P=0.01), max%HRR (P=0.006) and mean EE (P=0.02) were observed. Significant gender×condition interactions for HRpeak (P=0.03), mean %HRR (P=0.02), mean METs (P=0.02) and mean EE (P=0.02) were found. In addition, a significant main effect for each condition was found in all variables (P<0.01). Our results showed that the exercise intensities of all 3 salsa dancing conditions were moderate. Findings showed some significant differences in exercise intensity between males and females and within conditions. Salsa dancing could be useful in achieving a significant training effect in people who have a low level of fitness.

  1. The Influence of Exercise Intensity on Frontal Electroencephalographic Asymmetry and Self-Reported Affect

    ERIC Educational Resources Information Center

    Woo, Minjung; Kim, Sungwoon; Kim, Jingu; Petruzzello, Steven J.; Hatfield, Bradley D.

    2010-01-01

    The "feel better" effect of exercise has been well established, but the optimal intensity needed to elicit a positive affective response is controversial. In addition, the mechanisms underlying such a response are unclear. To clarify these issues, female undergraduate students were monitored for electroencephalographic (EEG) and self-reported…

  2. Thymus recovery after intensive physical exercise under conditions of immunocorrection and without it.

    PubMed

    Sapin, M R; Tkachuk, M G

    2005-11-01

    Exogenous antioxidants, e.g. tocopherol, prevent undesirable changes in the thymus and accelerate its recovery after intensive physical exercise. Four weeks after the end of training (swimming) the general structure of the thymus and content of LPO products in rats treated with tocopherol corresponded to the control values, in contrast to animals receiving no correction.

  3. Joint Cooling does not Hinder Athletic Performance during High-intensity Intermittent Exercise.

    PubMed

    Kim, H; Lee, D; Choi, H-M; Park, J

    2016-07-01

    We examined the effects of ankle and knee joint cooling on 20-m sprint times and maximal vertical jump heights during high-intensity intermittent exercise. 21 healthy collegiate male basketball (n=14) and handball players (n=7) underwent 3 experimental sessions. Each session consisted of four 15-min quarters of high-intensity intermittent exercises including various intensities of 20-m shuttle running and jumping. A 20-min bilateral joint cooling (ankle, knee, or control-no cooling: in a counterbalanced order) was applied before quarters 1 and 3. After joint cooling, no warm-up activity other than the exercise protocol was given. The 20-m sprint times and maximal vertical jump heights in each experimental session were recorded at baseline (prior to quarter-1) and during each quarter. To test joint cooling effects over time, we performed 3×5 mixed model ANOVAs. Neither ankle nor knee joint cooling changed 20-m sprint times (F8,280=1.45; p=0.18) or maximal vertical jump heights (F8,280=0.76; p=0.64). However, a trend was observed in which joint cooling immediately decreased (quarters 1 and 3) but active warm-up for approximately 20 min improved 20-min sprint times (quarters 2 and 4). Our study suggests that athletic performance such as sprinting and jumping are not altered by joint cooling applied prior to or during high-intensity intermittent exercise.

  4. Exercise intensity and the protection from postprandial vascular dysfunction in adolescents.

    PubMed

    Bond, B; Gates, P E; Jackman, S R; Corless, L M; Williams, C A; Barker, A R

    2015-06-01

    Acute exercise transiently improves endothelial function and protects the vasculature from the deleterious effects of a high-fat meal (HFM). We sought to identify whether this response is dependent on exercise intensity in adolescents. Twenty adolescents (10 male, 14.3 ± 0.3 yr) completed three 1-day trials: 1) rest (CON); 2) 8 × 1 min cycling at 90% peak power with 75 s recovery [high-intensity interval exercise (HIIE)]; and 3) cycling at 90% of the gas exchange threshold [moderate-intensity exercise (MIE)] 1 h before consuming a HFM (1.50 g/kg fat). Macrovascular and microvascular endothelial function was assessed before and immediately after exercise and 3 h after the HFM by flow-mediated dilation (FMD) and laser Doppler imaging [peak reactive hyperemia (PRH)]. FMD and PRH increased 1 h after HIIE [P < 0.001, effect size (ES) = 1.20 and P = 0.048, ES = 0.56] but were unchanged after MIE. FMD and PRH were attenuated 3 h after the HFM in CON (P < 0.001, ES = 1.78 and P = 0.02, ES = 0.59). FMD remained greater 3 h after the HFM in HIIE compared with MIE (P < 0.001, ES = 1.47) and CON (P < 0.001, ES = 2.54), and in MIE compared with CON (P < 0.001, ES = 1.40). Compared with CON, PRH was greater 3 h after the HFM in HIIE (P = 0.02, ES = 0.71) and MIE (P = 0.02, ES = 0.84), with no differences between HIIE and MIE (P = 0.72, ES = 0.16). Plasma triacylglycerol concentration and total antioxidant status concentration were not different between trials. We conclude that exercise intensity plays an important role in protecting the vasculature from the deleterious effects of a HFM. Performing HIIE may provide superior vascular benefits than MIE in adolescent groups. PMID:25820392

  5. 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. PMID:24091353

  6. Exercise intensity and oxygen uptake kinetics in African-American and Caucasian women

    PubMed Central

    Lai, Nicola; Tolentino-Silva, Fatima; Nasca, Melita M.; Silva, Marco A.; Gladden, L. Bruce; Cabrera, Marco E.

    2012-01-01

    The effect of exercise intensity on the on- and off-transient kinetics of oxygen uptake (VO2) was investigated in African American (AA) and Caucasian (C) women. African American (n=7) and Caucasian (n=6) women of similar age, body mass index and weight, performed an incremental test and bouts of square-wave exercise at moderate, heavy and very heavy intensities on a cycle ergometer. Gas exchange threshold (LTGE) was lower in AA (13.6±2.3mL·kg−1min−1) than C (18.6±5.6mL·kg−1min−1). The dynamic exercise and recovery VO2 responses were characterized by mathematical models. There were no significant differences in 1) peak oxygen uptake (VO2peak) between AA (28.5±5mL kg−1min−1) and C (31.1±6.6mL kg−1min−1) and 2) VO2 kinetics at any exercise intensity. At moderate exercise, the on- and off- VO2 kinetics was described by a mono-exponential function with similar time constants τ1,on (39.4±12.5s;38.8±15s) and τ1,off (52.7±10.1s;40.7±4.4s) for AA and C, respectively. At heavy and very heavy exercise, the VO2 kinetics was described by a double-exponential function. The parameter values for heavy and very heavy exercise in the AA group were respectively: τ1,on (47.0±10.8;44.3±10s), τ2,on (289±63;219±90s), τ1,off (45.9±6.2;50.7±10s), τ2,off (259±120;243±93s) while in the C group were respectively: τ1,on (41±12;43.2±15s); τ2,on(277±81;215±36s), τ1,off (40.2±3.4;42.3±7.2s), τ2,off (215±133;228±64s). The on- and off-transients were symmetrical with respect to model order and dependent on exercise intensity regardless of race. Despite similar VO2 kinetics, LTGE and gain of the VO2 on-kinetics at moderate intensity were lower in AA than C. However, generalization to the African American and Caucasian populations is constrained by the small subject numbers. PMID:21717119

  7. Intensity and duration of intermittent exercise and recovery during a soccer match.

    PubMed

    Orendurff, Michael S; Walker, Jason D; Jovanovic, Mladen; Tulchin, Kirsten L; Levy, Morris; Hoffmann, David K

    2010-10-01

    Soccer is a sport consisting of high-intensity intermittent exercise, with players making forays across their anaerobic threshold for tactical advantage followed by periods of recovery. The intensity and duration of these work and recovery bouts were defined during a men's soccer match using StepWatch Activity Monitors recording step rate for each 3-second period. The data were coded by custom software to separate work bouts (step rate ≥ 4) from recovery bouts (step rate < 4), and a square wave of the pattern of bouts was plotted for 5 players: center forward, central midfielder, wing midfielder, central defender, and wing defender. Four values were calculated for each work and recovery bout identified: duration, and mean, maximum, and minimum step rate (intensity). This novel technique provided detailed graphical information on the duration and exercise intensity of each position throughout the match. The center midfielder was able to sustain work and recovery bout characteristics throughout the match and appeared to recover at higher intensity levels than other players. The forward showed the consequence of accumulated fatigue late in the match and was unable to sustain the duration of high-intensity work bouts observed earlier in the match. The central defender attenuated the intensity of his work and recovery bouts late in the match staying closer to a more moderate work rate with fewer high- or low-intensity bouts. Having objective data qualifying players' work and recovery bout characteristics might prove valuable for tactical decision making, substitution timing, and for planning future training sessions.

  8. Intensive aerobic and muscle endurance exercise in patients with systemic sclerosis: a pilot study

    PubMed Central

    2014-01-01

    Background No previous studies have examined the effect of intensive exercise in systemic sclerosis patients with pulmonary impairment. The objective of this study was to examine the effect of an eight-week intensive aerobic exercise and muscle endurance training program for patients with systemic sclerosis with 50–100% of forced vital capacity. Methods A single-subject experimental design with repeated systematic measures during a six week A-phase (non-interventional baseline period) and an eight week B-phase (exercise intervention period) was used. Three women and one man with median age 66 years and median disease duration of 3.5 years completed aerobic exercise corresponding to 15 on the Borg RPE scale (strenuous) and muscular endurance training three times/week. Physical capacity (six-minute walk test), aerobic capacity (submaximal treadmill test) and muscle endurance in shoulder and hip flexion (Functional Index 2) were assessed every other week throughout the 14-week study. Activity limitation (Health Assessment Questionnaire), quality of life (Short Form 36), Raynaud, Fatigue and Global Health during the recent week (Visual Analogue Scales) were assessed at weeks 0, 6, 14. Results Three participants improved significantly in muscular endurance, and two participants improved significantly or clinically relevant in aerobic capacity. All other variables remained unchanged, except for a trend towards reduced fatigue. Conclusions This eight week exercise program was largely successful with positive effects on aerobic capacity and muscle endurance. Trial registration Clinicaltrials.gov Identifier: NCT01813578 PMID:24507585

  9. Repeated high-intensity interval exercise shortens the positive effect on executive function during post-exercise recovery in healthy young males.

    PubMed

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

    2016-06-01

    A single bout of aerobic exercise improves executive function (EF), but only for a short period. Compared with a single bout of aerobic exercise, we recently found that high-intensity interval exercise (HIIE) could maintain a longer improvement in EF. However, the mechanism underlying the effect of different exercise modes on the modifications of EF remains unclear. The purpose of the current investigation was to test our hypothesis that the amount of exercise-induced lactate production and its accumulation affects human brain function during and after exercise, thereby affecting post-exercise EF. Ten healthy male subjects performed cycle ergometer exercise. The HIIE protocol consisted of four 4-min bouts at 90% peak VO2 with a 3-min active recovery period at 60% peak VO2. The amount of lactate produced during exercise was manipulated by repeating the HIIE twice with a resting period of 60min between the 1st HIIE and 2nd HIIE. To evaluate EF, a color-word Stroop task was performed, and reverse-Stroop interference scores were obtained. EF immediately after the 1st HIIE was significantly improved compared to that before exercise, and the improved EF was sustained during 40min of the post-exercise recovery. However, for the 2nd HIIE, the improved EF was sustained for only 10min of the post-exercise recovery period, despite the performance of the same exercise. In addition, during and following HIIE, the glucose and lactate accumulation induced by the 2nd HIIE was significantly lower than that induced by the 1st HIIE. Furthermore, there was an inverse relationship between lactate and EF by plotting the changes in lactate levels against changes in EF from pre-exercise during the late phase of post-exercise recovery. These findings suggested the possibility that repeated bouts of HIIE, which decreases lactate accumulation, may dampen the positive effect of exercise on EF during the post-exercise recovery.

  10. Repeated high-intensity interval exercise shortens the positive effect on executive function during post-exercise recovery in healthy young males.

    PubMed

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

    2016-06-01

    A single bout of aerobic exercise improves executive function (EF), but only for a short period. Compared with a single bout of aerobic exercise, we recently found that high-intensity interval exercise (HIIE) could maintain a longer improvement in EF. However, the mechanism underlying the effect of different exercise modes on the modifications of EF remains unclear. The purpose of the current investigation was to test our hypothesis that the amount of exercise-induced lactate production and its accumulation affects human brain function during and after exercise, thereby affecting post-exercise EF. Ten healthy male subjects performed cycle ergometer exercise. The HIIE protocol consisted of four 4-min bouts at 90% peak VO2 with a 3-min active recovery period at 60% peak VO2. The amount of lactate produced during exercise was manipulated by repeating the HIIE twice with a resting period of 60min between the 1st HIIE and 2nd HIIE. To evaluate EF, a color-word Stroop task was performed, and reverse-Stroop interference scores were obtained. EF immediately after the 1st HIIE was significantly improved compared to that before exercise, and the improved EF was sustained during 40min of the post-exercise recovery. However, for the 2nd HIIE, the improved EF was sustained for only 10min of the post-exercise recovery period, despite the performance of the same exercise. In addition, during and following HIIE, the glucose and lactate accumulation induced by the 2nd HIIE was significantly lower than that induced by the 1st HIIE. Furthermore, there was an inverse relationship between lactate and EF by plotting the changes in lactate levels against changes in EF from pre-exercise during the late phase of post-exercise recovery. These findings suggested the possibility that repeated bouts of HIIE, which decreases lactate accumulation, may dampen the positive effect of exercise on EF during the post-exercise recovery. PMID:27060507

  11. Locomotor Muscle Fatigue Does Not Alter Oxygen Uptake Kinetics during High-Intensity Exercise

    PubMed Central

    Hopker, James G.; Caporaso, Giuseppe; Azzalin, Andrea; Carpenter, Roger; Marcora, Samuele M.

    2016-01-01

    The V˙O2 slow component (V˙O2sc) that develops during high-intensity aerobic exercise is thought to be strongly associated with locomotor muscle fatigue. We sought to experimentally test this hypothesis by pre-fatiguing the locomotor muscles used during subsequent high-intensity cycling exercise. Over two separate visits, eight healthy male participants were asked to either perform a non-metabolically stressful 100 intermittent drop-jumps protocol (pre-fatigue condition) or rest for 33 min (control condition) according to a random and counterbalanced order. Locomotor muscle fatigue was quantified with 6-s maximal sprints at a fixed pedaling cadence of 90 rev·min−1. Oxygen kinetics and other responses (heart rate, capillary blood lactate concentration and rating of perceived exertion, RPE) were measured during two subsequent bouts of 6 min cycling exercise at 50% of the delta between the lactate threshold and V˙O2max determined during a preliminary incremental exercise test. All tests were performed on the same cycle ergometer. Despite significant locomotor muscle fatigue (P = 0.03), the V˙O2sc was not significantly different between the pre-fatigue (464 ± 301 mL·min−1) and the control (556 ± 223 mL·min−1) condition (P = 0.50). Blood lactate response was not significantly different between conditions (P = 0.48) but RPE was significantly higher following the pre-fatiguing exercise protocol compared with the control condition (P < 0.01) suggesting higher muscle recruitment. These results demonstrate experimentally that locomotor muscle fatigue does not significantly alter the V˙O2 kinetic response to high intensity aerobic exercise, and challenge the hypothesis that the V˙O2sc is strongly associated with locomotor muscle fatigue. PMID:27790156

  12. Effects of high-intensity interval vs. continuous moderate exercise on intraocular pressure.

    PubMed

    Conte, M; Baldin, A D; Russo, M R R R; Storti, L R; Caldara, A A; Cozza, H F P; Ciolac, E G

    2014-09-01

    Our purpose was to compare the acute effects of high-intensity interval training (HIT) vs. continuous moderate exercise (CME) on intraocular pressure (IOP) in healthy subjects. Fifteen young men (age=22.1±6 years) underwent 30 min of HIT (2 min of walking at 50% of reserve heart rate (HR) alternated with 1 min of running at 80% of reserve HR) and CME sessions (30 min of jogging/running at 60% of reserve HR) in random order (2-5 days between sessions). IOP was measured before (baseline), immediately after (post--exercise), 5 min after (Rec5) and 10 min after (Rec10) each exercise session. IOP was reduced post-exercise and remained reduced at Rec5 during both HIT and CME session, with no significant difference between interventions (~16% between 23%). However, IOP remained reduced at Rec10 only after HIT intervention (~19%), whereas IOP at Rec10 returned to levels similar to the observed at baseline during CME intervention. In summary, both HIT and CME equally reduced IOP immediately and 5 min after exercise session. However, only HIT was able to remain IOP reduced 10 min after exercise. These results suggest that HIT may be more effective than CME for reducing IOP in young healthy men.

  13. Cardiorespiratory responses and reduced apneic time to cold-water face immersion after high intensity exercise.

    PubMed

    Konstantinidou, Sylvia; Soultanakis, Helen

    2016-01-01

    Apnea after exercise may evoke a neurally mediated conflict that may affect apneic time and create a cardiovascular strain. The physiological responses, induced by apnea with face immersion in cold water (10 °C), after a 3-min exercise bout, at 85% of VO2max,were examined in 10 swimmers. A pre-selected 40-s apnea, completed after rest (AAR), could not be met after exercise (AAE), and was terminated with an agonal gasp reflex, and a reduction of apneic time, by 75%. Bradycardia was evident with immersion after both, 40-s of AAR and after AAE (P<0.05). The dramatic elevation of, systolic pressure and pulse pressure, after AAE, were indicative of cardiovascular stress. Blood pressure after exercise without apnea was not equally elevated. The activation of neurally opposing functions as those elicited by the diving reflex after high intensity exercise may create an autonomic conflict possibly related to oxygen-conserving reflexes stimulated by the trigeminal nerve, and those elicited by exercise. PMID:26343750

  14. Cardiorespiratory responses and reduced apneic time to cold-water face immersion after high intensity exercise.

    PubMed

    Konstantinidou, Sylvia; Soultanakis, Helen

    2016-01-01

    Apnea after exercise may evoke a neurally mediated conflict that may affect apneic time and create a cardiovascular strain. The physiological responses, induced by apnea with face immersion in cold water (10 °C), after a 3-min exercise bout, at 85% of VO2max,were examined in 10 swimmers. A pre-selected 40-s apnea, completed after rest (AAR), could not be met after exercise (AAE), and was terminated with an agonal gasp reflex, and a reduction of apneic time, by 75%. Bradycardia was evident with immersion after both, 40-s of AAR and after AAE (P<0.05). The dramatic elevation of, systolic pressure and pulse pressure, after AAE, were indicative of cardiovascular stress. Blood pressure after exercise without apnea was not equally elevated. The activation of neurally opposing functions as those elicited by the diving reflex after high intensity exercise may create an autonomic conflict possibly related to oxygen-conserving reflexes stimulated by the trigeminal nerve, and those elicited by exercise.

  15. Effect of high-intensity intermittent exercise on postprandial plasma triacylglycerol in sedentary young women.

    PubMed

    Tan, Martin; Chan Moy Fat, Rachel; Boutcher, Yati N; Boutcher, Stephen H

    2014-02-01

    High-intensity intermittent exercise (HIIE) such as the 30-s Wingate test attenuates postprandial triacylglycerol (TG), however, the ability of shorter versions of HIIE to reduce postprandial TG is undetermined. Thus, the effect of 8-s sprinting bouts of HIIE on blood TG levels of 12 females after consumption of a high-fat meal (HFM) was examined. Twelve young, sedentary women (BMI 25.1 ± 2.3 kg/m²; age 21.3 ± 2.1 years) completed a maximal oxygen uptake test and then on different days underwent either an exercise or a no-exercise postprandial TG condition. Both conditions involved consuming a HFM after a 12-hr fast. The HFM, in milkshake form provided 4170 kJ (993 Kcal) of energy and 98 g fat. Order was counter-balanced. In the exercise condition participants completed 20-min of HIIE cycling consisting of repeated bouts of 8 s sprint cycling (100-115 rpm) and 12 s of active rest (easy pedaling) 14 hr before consuming the HFM. Blood samples were collected hourly after the HFM for 4 hr. Total postprandial TG was 13% lower, p = .004, in the exercise (5.84 ± 1.08 mmol L⁻¹ 4 h⁻¹) compared with the no-exercise condition (6.71 ± 1.63 mmol L⁻¹ 4 h⁻¹). In conclusion, HIIE significantly attenuated postprandial TG in sedentary young women. PMID:24092770

  16. Reliability of telemetric electromyography and near-infrared spectroscopy during high-intensity resistance exercise.

    PubMed

    Scott, Brendan R; Slattery, Katie M; Sculley, Dean V; Lockie, Robert G; Dascombe, Ben J

    2014-10-01

    This study quantified the inter- and intra-test reliability of telemetric surface electromyography (EMG) and near infrared spectroscopy (NIRS) during resistance exercise. Twelve well-trained young men performed high-intensity back squat exercise (12 sets at 70-90% 1-repetition maximum) on two occasions, during which EMG and NIRS continuously monitored muscle activation and oxygenation of the thigh muscles. Intra-test reliability for EMG and NIRS variables was generally higher than inter-test reliability. EMG median frequency variables were generally more reliable than amplitude-based variables. The reliability of EMG measures was not related to the intensity or number of repetitions performed during the set. No notable differences were evident in the reliability of EMG between different agonist muscles. NIRS-derived measures of oxyhaemoglobin, deoxyhaemoglobin and tissue saturation index were generally more reliable during single-repetition sets than multiple-repetition sets at the same intensity. Tissue saturation index was the most reliable NIRS variable. Although the reliability of the EMG and NIRS measures varied across the exercise protocol, the precise causes of this variability are not yet understood. However, it is likely that biological variation during multi-joint isotonic resistance exercise may account for some of the variation in the observed results.

  17. Effect of dietary nitrate supplementation on tolerance to supramaximal intensity intermittent exercise.

    PubMed

    Aucouturier, Julien; Boissière, Julien; Pawlak-Chaouch, Mehdi; Cuvelier, Grégory; Gamelin, François-Xavier

    2015-09-15

    Dietary nitrate (NO3(-)) supplementation has been shown to increase exercise tolerance and improve oxidative efficiency during aerobic exercise in healthy subjects. We tested the hypothesis that a 3-day supplementation in beetroot juice (BJ) rich in NO3(-) would improve the tolerance to supramaximal intensity intermittent exercise consisting of 15-s exercise periods at 170% of the maximal aerobic power interspersed with 30-s passive recovery periods. The number of repetitions completed before reaching volitional exhaustion was significantly higher in the BJ than in the placebo condition (26.1 ± 10.7 versus 21.8 ± 8.0 respectively, P < 0.05). In contrast to previous findings during exercise performed at intensity below the peak oxygen uptake (VO2peak), oxygen uptake (VO2) was unaffected (BJ: 2735 ± 345 mL kg(-1) min(-1) vs. placebo: 2787 ± 346 mL kg(-1) min(-1), NS). However, the Area Under the Curve for microvascular total hemoglobin (AUC-THb) in the vastus lateralis muscle assessed by near infrared spectroscopy during 3 time-matched repetitions was significantly increased with NO3(-) supplementation (BJ: 9662 ± 1228 a.u. vs. placebo:8178 ± 1589 a.u.; P < 0.05). Thus, increased NO3(-) (BJ: 421.5 ± 107.4 μM vs placebo:39.4 ± 18.0 μM) and NO2(-) (BJ: 441 ± 184 nM vs placebo: 212 ± 119 nM) plasma levels (P < 0.001 for both) are associated with improved muscle microvascular Red Blood Cell (RBC) concentration and O2 delivery during intense exercise, despite no effect on resting femoral artery blood flow, and vascular conductance. Maximal voluntary force during an isometric leg extensor exercise, and blood lactate levels were also unaffected by NO3(-) supplementation. To conclude, dietary NO3(-) supplementation enhances tolerance to exercise at supramaximal intensity, with increased microvascular total RBC concentration in the working muscle, in the absence of effect on contractile function and resting hemodynamic parameters. PMID:26028570

  18. Sex difference in substrate oxidation during low-intensity isometric exercise in young adults.

    PubMed

    Sarafian, Delphine; Schutz, Yves; Montani, Jean-Pierre; Dulloo, Abdul G; Miles-Chan, Jennifer L

    2016-09-01

    Low-intensity physical activity is increasingly promoted as an alternative to sedentary behavior. However, much research to date has focused on moderate- to vigorous-intensity physical activity, and in particular dynamic work, with the effect of low-intensity isometric exercise (<4 METs) on substrate utilization yet to be explored. Here we investigate the effects of such exercise on respiratory quotient (RQ) and determine the extent of intra- and inter-individual variability in response. Energy expenditure, RQ, and substrate oxidation were measured by ventilated-hood indirect calorimetry at rest and in response to standardized, intermittent, low-level isometric leg-press exercises at 5 loads (+5, +10, +15, +20, +25 kg) in 26 healthy, young adults. Nine participants repeated the experiment on 3 separate days to assess within-subject, between-day variability. There was no significant difference in energy cost and heart rate responses to low-intensity isometric exercise (<2 METs) between men and women. However, a sex difference was apparent in terms of substrate oxidation - with men increasing both fat and carbohydrate oxidation, and women only increasing fat oxidation while maintaining carbohydrate oxidation at baseline, resting levels. This sex difference was repeatable and persisted when substrate oxidation was adjusted for differences in body weight or body composition. Individual variability in RQ was relatively low, with both intra- and inter-individual coefficients of variation in the range of 3%-6% in both sexes. These results suggest that women preferentially increase fat oxidation during low-level isometric exercise. Whether such physical activity could be incorporated into treatment/prevention strategies aimed at optimizing fat oxidation in women warrants further investigation.

  19. Sex difference in substrate oxidation during low-intensity isometric exercise in young adults.

    PubMed

    Sarafian, Delphine; Schutz, Yves; Montani, Jean-Pierre; Dulloo, Abdul G; Miles-Chan, Jennifer L

    2016-09-01

    Low-intensity physical activity is increasingly promoted as an alternative to sedentary behavior. However, much research to date has focused on moderate- to vigorous-intensity physical activity, and in particular dynamic work, with the effect of low-intensity isometric exercise (<4 METs) on substrate utilization yet to be explored. Here we investigate the effects of such exercise on respiratory quotient (RQ) and determine the extent of intra- and inter-individual variability in response. Energy expenditure, RQ, and substrate oxidation were measured by ventilated-hood indirect calorimetry at rest and in response to standardized, intermittent, low-level isometric leg-press exercises at 5 loads (+5, +10, +15, +20, +25 kg) in 26 healthy, young adults. Nine participants repeated the experiment on 3 separate days to assess within-subject, between-day variability. There was no significant difference in energy cost and heart rate responses to low-intensity isometric exercise (<2 METs) between men and women. However, a sex difference was apparent in terms of substrate oxidation - with men increasing both fat and carbohydrate oxidation, and women only increasing fat oxidation while maintaining carbohydrate oxidation at baseline, resting levels. This sex difference was repeatable and persisted when substrate oxidation was adjusted for differences in body weight or body composition. Individual variability in RQ was relatively low, with both intra- and inter-individual coefficients of variation in the range of 3%-6% in both sexes. These results suggest that women preferentially increase fat oxidation during low-level isometric exercise. Whether such physical activity could be incorporated into treatment/prevention strategies aimed at optimizing fat oxidation in women warrants further investigation. PMID:27540628

  20. Exercise at anaerobic threshold intensity and insulin secretion by isolated pancreatic islets of rats

    PubMed Central

    de Oliveira, Camila Aparecida Machado; Paiva, Mauricio Ferreira; Mota, Clécia Alencar Soares; Ribeiro, Carla; de Almeida Leme, José Alexandre Curiacos; Luciano, Eliete

    2010-01-01

    To evaluate the effect of acute exercise and exercise training at the anaerobic threshold (AT) intensity on aerobic conditioning and insulin secretion by pancreatic islets, adult male Wistar rats were submitted to the lactate minimum test (LMT) for AT determination. Half of the animals were submitted to swimming exercise training (trained), 1 h/day, 5 days/week during 8 weeks, with an overload equivalent to the AT. The other half was kept sedentary. At the end of the experimental period, the rats were submitted to an oral glucose tolerance test and to another LMT. Then, the animals were sacrificed at rest or immediately after 20 minutes of swimming exercise at the AT intensity for pancreatic islets isolation. At the end of the experiment mean workload (% bw) at AT was higher and blood lactate concentration (mmol/L) was lower in the trained than in the control group. Rats trained at the AT intensity showed no alteration in the areas under blood glucose and insulin during OGTT test. Islet insulin content of trained rats was higher than in the sedentary rats while islet glucose uptake did not differ among the groups. The static insulin secretion in response to the high glucose concentration (16.7 mM) of the sedentary group at rest was lower than the sedentary group submitted to the acute exercise and the inverse was observed in relation to the trained groups. Physical training at the AT intensity improved the aerobic condition and altered insulin secretory pattern by pancreatic islets. PMID:21099318

  1. Neuromuscular function following prolonged intense self-paced exercise in hot climatic conditions.

    PubMed

    Périard, Julien D; Cramer, Matthew N; Chapman, Phillip G; Caillaud, Corinne; Thompson, Martin W

    2011-08-01

    Muscle weakness following constant load exercise under heat stress has been associated with hyperthermia-induced central fatigue. However, evidence of central fatigue influencing intense self-paced exercise in the heat is lacking. The purpose of this investigation was to evaluate force production capacity and central nervous system drive in skeletal muscle pre- and post-cycle ergometer exercise in hot and cool conditions. Nine trained male cyclists performed a 20-s maximal voluntary isometric contraction (MVC) prior to (control) and following a 40-km time trial in hot (35°C) and cool (20°C) conditions. MVC force production and voluntary activation of the knee extensors was evaluated via percutaneous tetanic stimulation. In the cool condition, rectal temperature increased to 39.0°C and reached 39.8°C in the heat (P < 0.01). Following exercise in the hot and cool conditions, peak force declined by ~90 and ~99 N, respectively, compared with control (P < 0.01). Mean force decreased by 15% (hot) and 14% (cool) (P < 0.01 vs. control). Voluntary activation during the post-exercise MVC declined to 93.7% (hot) and 93.9% (cool) (P < 0.05 vs. control). The post-exercise decline in voluntary activation represented ~20% of the decrease in mean force production in both conditions. Therefore, the additional increase in rectal temperature did not exacerbate the loss of force production following self-paced exercise in the heat. The impairment in force production indicates that the fatigue exhibited by the quadriceps is mainly of peripheral origin and a consequence of the prolonged contractile activity associated with exercise. PMID:21188412

  2. Quantification of absolute myocardial perfusion at rest and during exercise with positron emission tomography after human cardiac transplantation

    SciTech Connect

    Krivokapich, J.; Stevenson, L.W.; Kobashigawa, J.; Huang, S.C.; Schelbert, H.R. )

    1991-08-01

    The maximal exercise capacity of cardiac transplant recipients is reduced compared with that of normal subjects. To determine if this reduced exercise capacity is related to inadequate myocardial perfusion during exercise, myocardial perfusion was measured noninvasively with use of positron emission tomography and nitrogen (N)-13 ammonia. Twelve transplant recipients with no angiographic evidence of accelerated coronary atherosclerosis were studied. Serial N-13 ammonia imaging was performed at rest and during supine bicycle exercise. The results were compared with those from 10 normal volunteers with a low probability of having cardiac disease. A two-compartment kinetic model for estimating myocardial perfusion was applied to the data. Transplant recipients achieved a significant lower exercise work load than did the volunteers (42 {plus minus} 16 vs. 128 {plus minus} 22 W), but a higher venous lactate concentration (31.3 {plus minus} 14.9 vs. 13.7 {plus minus} 4.1 mg/100 ml). Despite the difference in exercise work load, there was no significant difference in the cardiac work achieved by transplant recipients and normal subjects as evidenced by similar rate-pressure products of 24,000 {plus minus} 3,400 versus 21,300 {plus minus} 2,800 betas/min per mm Hg, respectively. In addition, myocardial blood flow during exercise was not significantly different between the two groups (1.70 {plus minus} 0.60 vs. 1.56 {plus minus} 0.71 ml/min per g, respectively). This study demonstrates that the myocardial flow response to the physiologic stress of exercise is appropriate in transplant recipients and does not appear to explain the decreased exercise capacity in these patients.

  3. Exercise intensity self-regulation using the OMNI scale in children with cystic fibrosis.

    PubMed

    Higgins, Linda W; Robertson, Robert J; Kelsey, Sheryl F; Olson, Marian B; Hoffman, Leslie A; Rebovich, Paul J; Haile, Luke; Orenstein, David M

    2013-05-01

    Prescribing exercise at intensities that improve fitness is difficult in children with cystic fibrosis (CF) due to ventilatory limitations and fluctuating health status. Our aim was to determine if children with CF could regulate the intensity of cycle ergometer and treadmill exercise using target ratings of perceived exertion (RPE) derived from the Children's OMNI Scale. We examined prescription congruence (similar oxygen consumption [VO₂] and heart rate [HR] for target RPE) and intensity discrimination (different VO₂ and HR for different RPEs), from cycle to cycle and cycle to treadmill. Subjects were 24 children (12 male, 12 female), aged 10-17 years with varying disease severity. Each child participated in one orientation, one estimation trial (graded maximal exercise test), and two production trials (cycle and treadmill, alternating between RPE 4 and 7). At RPE 4, congruence was evident for both VO₂ and HR on the treadmill. On the cycle at RPE 4, VO₂ was significantly higher only in the first production trial, although HRs tended to be higher in the production trials than the estimation trial. Prescription congruence was also supported at RPE 7, with no significant differences in VO₂ or HR between estimation and production trials on cycle or treadmill. Results fully supported intensity discrimination, with significant differences between VO₂ and HR at RPE 4 and 7 (P < 0.0001). Children with CF appear capable of using the OMNI Scale to regulate cycle and treadmill exercise intensity. Training using this methodology has the potential to promote fitness in children with CF of varying severity. PMID:22997144

  4. Exercise Intensity Self-Regulation using the OMNI Scale in Children with Cystic Fibrosis

    PubMed Central

    Higgins, Linda W.; Robertson, Robert J.; Kelsey, Sheryl F.; Olson, Marian B.; Hoffman, Leslie A.; Rebovich, Paul J.; Haile, Luke; Orenstein, David M.

    2012-01-01

    Summary Prescribing exercise at intensities that improve fitness is difficult in children with cystic fibrosis (CF) due to ventilatory limitations and fluctuating health status. Our aim was to determine if children with CF could regulate the intensity of cycle ergometer and treadmill exercise using target ratings of perceived exertion (RPE) derived from the Children’s OMNI Scale. We examined prescription congruence [similar oxygen consumption (VO2) and heart rate (HR) for target RPE] and intensity discrimination (different VO2 and HR for different RPEs), from cycle to cycle and cycle to treadmill. Subjects were 24 children (12 male, 12 female), aged 10–17 years with varying disease severity. Each child participated in one orientation, one estimation trial (graded maximal exercise test), and two production trials (cycle and treadmill, alternating between RPE 4 and 7). At RPE 4, congruence was evident for both VO2 and HR on the treadmill. On the cycle at RPE 4, VO2 was significantly higher only in the first production trial, although HRs tended to be higher in the production trials than the estimation trial. Prescription congruence was also supported at RPE 7, with no significant differences in VO2 or HR between estimation and production trials on cycle or treadmill. Results fully supported intensity discrimination, with significant differences between VO2 and HR at RPE 4 and 7 (p<0.0001). Children with CF appear capable of using the OMNI Scale to regulate cycle and treadmill exercise intensity. Training using this methodology has the potential to promote fitness in children with CF of varying severity. PMID:22997144

  5. Concurrent Validity of a Velocity Perception Scale to Monitor Back Squat Exercise Intensity in Young Skiers.

    PubMed

    Bautista, Iker J; Chirosa, Ignacio J; Robinson, Joseph E; Chirosa, Luis J; Martínez, Isidoro

    2016-02-01

    Execution velocity is among the main variables used to quantify resistance exercise intensity. The velocity at which a given load is displaced is one of the factors, which determine the training adaptations induced in the muscles. The purpose of this study was to assess the validity of the scale of perceived velocity (SPV) applied to the back squat. The study participants were 11 international level young elite skiers (8 men and 3 women) of mean age, height, weight, and estimated 1-repetition maximum/body weight ratio (1RMest/BW) 15.4 ± 1.12 years, 166.8 ± 8.83 cm, 63.6 ± 11.56 kg, and 1.61 ± 0.40, respectively. Participants performed a 2-stage protocol. In the first stage (familiarization), subjects were instructed on how to use the scale and performed an incremental load test to determine their 1RMest. In the second, or validation stage (72 hours later), exercises were executed at 6 relative intensities (20, 30, 40, 50, 60, and 70% of 1RMest) in random order in 2 sessions separated by 72 hours. Real velocity (Velreal) and perceived velocity (Velscale) values were linearly distributed showing excellent coefficients of determination (R(2) = 0.98 and R(2) = 0.99 for the 2-session trial). A 2-way repeated measures analysis of variance (scale [2] × session [2] × intensity [6]) revealed significant differences in the factor intensity and the interaction scale × intensity (no significant differences were detected in scale, session, scale × session, or scale × session × intensity). These data support the validity of SPV to monitor exercise intensity during lower-body strength training. PMID:26244826

  6. Local infusion of ascorbate augments NO-dependent cutaneous vasodilatation during intense exercise in the heat

    PubMed Central

    Meade, Robert D; Fujii, Naoto; Alexander, Lacy M; Paull, Gabrielle; Louie, Jeffrey C; Flouris, Andreas D; Kenny, Glen P

    2015-01-01

    Abstract Nitric oxide (NO)-dependent cutaneous vasodilatation is reportedly diminished during exercise performed at a high (700 W) relative to moderate (400 W) rate of metabolic heat production. The present study evaluated whether this impairment results from increased oxidative stress associated with an accumuluation of reactive oxygen species (ROS) during high intensity exercise. On two separate days, 11 young (mean ± SD, 24 ± 4 years) males cycled in the heat (35°C) at a moderate (500 W) or high (700 W) rate of metabolic heat production. Each session included two 30 min exercise bouts followed by 20 and 40 min of recovery, respectively. Cutaneous vascular conductance (CVC) was monitored at four forearm skin sites continuously perfused via intradermal microdialysis with: (1) lactated Ringer solution (Control); (2) 10 mm ascorbate (Ascorbate); (3) 10 mm l-NAME; or (4) 10 mm ascorbate + 10 mm l-NAME (Ascorbate + l-NAME). At the end of each 500 W exercise bout, CVC was attenuated with l-NAME (∼35% CVCmax) and Ascorbate + l-NAME (∼43% CVCmax) compared to Control (∼60% CVCmax; all P < 0.04); however, Ascorbate did not modulate CVC during exercise (∼60% CVCmax; both P > 0.87). Conversely, CVC was elevated with Ascorbate (∼72% CVCmax; both P < 0.03) but remained similar to Control (∼59% CVCmax) with l-NAME (∼50% CVCmax) and Ascorbate + l-NAME (∼47% CVCmax; all P > 0.05) at the end of both 700 W exercise bouts. We conclude that oxidative stress associated with an accumulation of ascorbate-sensitive ROS impairs NO-dependent cutaneous vasodilatation during intense exercise. Key points Recent work demonstrates that nitric oxide (NO) contributes to cutaneous vasodilatation during moderate (400 W of metabolic heat production) but not high (700 W of metabolic heat production) intensity exercise bouts performed in the heat (35°C). The present study evaluated whether the impairment in NO-dependent cutaneous vasodilatation

  7. How to regulate the acute physiological response to "aerobic" high-intensity interval exercise.

    PubMed

    Tschakert, Gerhard; Kroepfl, Julia; Mueller, Alexander; Moser, Othmar; Groeschl, Werner; Hofmann, Peter

    2015-03-01

    The acute physiological processes during "aerobic" high-intensity interval exercise (HIIE) and their regulation are inadequately studied. The main goal of this study was to investigate the acute metabolic and cardiorespiratory response to long and short HIIE compared to continuous exercise (CE) as well as its regulation and predictability. Six healthy well-trained sport students (5 males, 1 female; age: 25.7 ± 3.1 years; height: 1.80 ± 0.04 m; weight: 76.7 ± 6.4 kg; VO2max: 4.33 ± 0.7 l·min(-1)) performed a maximal incremental exercise test (IET) and subsequently three different exercise sessions matched for mean load (Pmean) and exercise duration (28 min): 1) long HIIE with submaximal peak workloads (Ppeak = power output at 95 % of maximum heart rate), peak workload durations (tpeak) of 4 min, and recovery durations (trec) of 3 min, 2) short HIIE with Ppeak according to the maximum power output (Pmax) from IET, tpeak of 20 s, and individually calculated trec (26.7 ± 13.4 s), and 3) CE with a target workload (Ptarget) equating to Pmean of HIIE. In short HIIE, mean lactate (Lamean) (5.22 ± 1.41 mmol·l(-1)), peak La (7.14 ± 2.48 mmol·l(-1)), and peak heart rate (HRpeak) (181.00 ± 6.66 b·min(-1)) were significantly lower compared to long HIIE (Lamean: 9.83 ± 2.78 mmol·l(-1); Lapeak: 12.37 ± 4.17 mmol·l(-1), HRpeak: 187.67 ± 5.72 b·min(-1)). No significant differences in any parameters were found between short HIIE and CE despite considerably higher peak workloads in short HIIE. The acute metabolic and peak cardiorespiratory demand during "aerobic" short HIIE was significantly lower compared to long HIIE and regulable via Pmean. Consequently, short HIIE allows a consciously aimed triggering of specific and desired or required acute physiological responses. Key pointsHigh-intensity interval exercise (HIIE) with short peak workload durations (tpeak) induce a lower acute metabolic and peak cardiorespiratory response compared to intervals with long tpeak

  8. Low volume-high intensity interval exercise elicits antioxidant and anti-inflammatory effects in humans.

    PubMed

    Wadley, Alex J; Chen, Yu-Wen; Lip, Gregory Y H; Fisher, James P; Aldred, Sarah

    2016-01-01

    The purpose of the present study was to compare acute changes in oxidative stress and inflammation in response to steady state and low volume, high intensity interval exercise (LV-HIIE). Untrained healthy males (n = 10, mean ± s: age 22 ± 3 years; VO2MAX 42.7 ± 5.0 ml · kg(-1) · min(-1)) undertook three exercise bouts: a bout of LV-HIIE (10 × 1 min 90% VO2MAX intervals) and two energy-matched steady-state cycling bouts at a moderate (60% VO2MAX; 27 min, MOD) and high (80% VO2MAX; 20 min, HIGH) intensity on separate days. Markers of oxidative stress, inflammation and physiological stress were assessed before, at the end of exercise and 30 min post-exercise (post+30). At the end of all exercise bouts, significant changes in lipid hydroperoxides (LOOH) and protein carbonyls (PCs) (LOOH (nM): MOD +0.36; HIGH +3.09; LV-HIIE +5.51 and PC (nmol · mg(-1) protein): MOD -0.24; HIGH -0.11; LV-HIIE -0.37) were observed. Total antioxidant capacity (TAC) increased post+30, relative to the end of all exercise bouts (TAC (µM): MOD +189; HIGH +135; LV-HIIE +102). Interleukin (IL)-6 and IL-10 increased post+30 in HIGH and LV-HIIE only (P < 0.05). HIGH caused the greatest lymphocytosis, adrenaline and cardiovascular response (P < 0.05). At a reduced energy cost and physiological stress, LV-HIIE elicited similar cytokine and oxidative stress responses to HIGH.

  9. Low Intensity Physical Exercise Attenuates Cardiac Remodeling and Myocardial Oxidative Stress and Dysfunction in Diabetic Rats

    PubMed Central

    Gimenes, C.; Gimenes, R.; Rosa, C. M.; Xavier, N. P.; Campos, D. H. S.; Fernandes, A. A. H.; Cezar, M. D. M.; Guirado, G. N.; Cicogna, A. C.; Takamoto, A. H. R.; Okoshi, M. P.; Okoshi, K.

    2015-01-01

    We evaluated the effects of a low intensity aerobic exercise protocol on cardiac remodeling and myocardial function in diabetic rats. Wistar rats were assigned into four groups: sedentary control (C-Sed), exercised control (C-Ex), sedentary diabetes (DM-Sed), and exercised diabetes (DM-Ex). Diabetes was induced by intraperitoneal injection of streptozotocin. Rats exercised for 9 weeks in treadmill at 11 m/min, 18 min/day. Myocardial function was evaluated in left ventricular (LV) papillary muscles and oxidative stress in LV tissue. Statistical analysis was given by ANOVA or Kruskal-Wallis. Echocardiogram showed diabetic groups with higher LV diastolic diameter-to-body weight ratio and lower posterior wall shortening velocity than controls. Left atrium diameter was lower in DM-Ex than DM-Sed (C-Sed: 5.73 ± 0.49; C-Ex: 5.67 ± 0.53; DM-Sed: 6.41 ± 0.54; DM-Ex: 5.81 ± 0.50 mm; P < 0.05 DM-Sed vs C-Sed and DM-Ex). Papillary muscle function was depressed in DM-Sed compared to C-Sed. Exercise attenuated this change in DM-Ex. Lipid hydroperoxide concentration was higher in DM-Sed than C-Sed and DM-Ex. Catalase and superoxide dismutase activities were lower in diabetics than controls and higher in DM-Ex than DM-Sed. Glutathione peroxidase activity was lower in DM-Sed than C-Sed and DM-Ex. Conclusion. Low intensity exercise attenuates left atrium dilation and myocardial oxidative stress and dysfunction in type 1 diabetic rats. PMID:26509175

  10. The effect of different intensities of treadmill exercise on cognitive function deficit following a severe controlled cortical impact in rats.

    PubMed

    Shen, Xiafeng; Li, Aiping; Zhang, Yuling; Dong, Xiaomin; Shan, Tian; Wu, Yi; Jia, Jie; Hu, Yongshan

    2013-01-01

    Exercise has been proposed for the treatment of traumatic brain injury (TBI). However, the proper intensity of exercise in the early phase following a severe TBI is largely unknown. To compare two different treadmill exercise intensities on the cognitive function following a severe TBI in its early phase, rats experienced a controlled cortical impact (CCI) and were forced to treadmill exercise for 14 days. The results revealed that the rats in the low intensity exercise group had a shorter latency to locate a platform and a significantly better improvement in spatial memory in the Morris water maze (MWM) compared to the control group (p < 0.05). The high intensity exercise group showed a longer latency and a mild improvement in spatial memory compared to the control group rats in the MWM; however, this difference was not statistically significant (p > 0.05). The brain-derived neurotrophic factor (BDNF) and p-CREB protein levels in the contralateral hippocampus were increased significantly in the low intensity exercise group. Our results suggest that 2 weeks of low intensity of treadmill exercise is beneficial for improving cognitive function and increasing hippocampal BDNF expression after a severe TBI in its early phase.

  11. Metabolic response of different high-intensity aerobic interval exercise protocols.

    PubMed

    Gosselin, Luc E; Kozlowski, Karl F; DeVinney-Boymel, Lee; Hambridge, Caitlin

    2012-10-01

    Although high-intensity sprint interval training (SIT) employing the Wingate protocol results in significant physiological adaptations, it is conducted at supramaximal intensity and is potentially unsafe for sedentary middle-aged adults. We therefore evaluated the metabolic and cardiovascular response in healthy young individuals performing 4 high-intensity (~90% VO2max) aerobic interval training (HIT) protocols with similar total work output but different work-to-rest ratio. Eight young physically active subjects participated in 5 different bouts of exercise over a 3-week period. Protocol 1 consisted of 20-minute continuous exercise at approximately 70% of VO2max, whereas protocols 2-5 were interval based with a work-active rest duration (in seconds) of 30/30, 60/30, 90/30, and 60/60, respectively. Each interval protocol resulted in approximately 10 minutes of exercise at a workload corresponding to approximately 90% VO2max, but differed in the total rest duration. The 90/30 HIT protocol resulted in the highest VO2, HR, rating of perceived exertion, and blood lactate, whereas the 30/30 protocol resulted in the lowest of these parameters. The total caloric energy expenditure was lowest in the 90/30 and 60/30 protocols (~150 kcal), whereas the other 3 protocols did not differ (~195 kcal) from one another. The immediate postexercise blood pressure response was similar across all the protocols. These finding indicate that HIT performed at approximately 90% of VO2max is no more physiologically taxing than is steady-state exercise conducted at 70% VO2max, but the response during HIT is influenced by the work-to-rest ratio. This interval protocol may be used as an alternative approach to steady-state exercise training but with less time commitment.

  12. Exercise training at the intensity of maximal fat oxidation in obese boys.

    PubMed

    Tan, Sijie; Wang, Jianxiong; Cao, Liquan

    2016-01-01

    The objectives of this study were to explore the effects of 10 weeks of exercise training at the intensity of maximal fat oxidation rate (FATmax) on body composition, cardiovascular fitness, and functional capacity in 8- to 10-year-old obese boys. This is a school-based interventional study. Twenty-six obese boys and 20 lean boys were randomly allocated into the exercise and control groups. Measurements of body composition, FATmax through gas analyses, predicted maximal oxygen uptake, and functional capacity (run, jump, abdominal muscle function, and body flexibility) were conducted at baseline and at the end of experiments. Two exercise groups participated in 10 weeks of supervised exercise training at individualized FATmax intensities, for 1 h per day and 5 days per week. FATmax training decreased body mass (-1.0 kg, p < 0.05), body mass index (-1.2 kg/m(2), p < 0.01), fat mass (-1.2 kg, p < 0.01), and abdominal fat (-0.13 kg, p < 0.01) of the trained obese boys. Their cardiovascular fitness (p < 0.05) and body flexibility (p < 0.05) were also improved after training. The lean boys showed improvements in cardiovascular fitness after training (p < 0.05). FATmax training increased the FATmax in obese boys from 0.35 ± 0.12 g/min to 0.38 ± 0.13 g/min, but this change was not statistically significant. In addition, there was no change in daily energy intake for all participants before and after the experimental period. Results of this study suggest that FATmax is an effective exercise training intensity for the treatment of childhood obesity.

  13. Social cognitive theory correlates of moderate-intensity exercise among adults with type 2 diabetes.

    PubMed

    Heiss, Valerie J; Petosa, R L

    2016-01-01

    The purpose of this study was to identify social cognitive theory (SCT) correlates of moderate- to vigorous-intensity exercise (MVPA) among adults with type 2 diabetes. Adults with type 2 diabetes (N = 181) participated in the study. Participants were recruited through ResearchMatch.org to complete an online survey. The survey used previously validated instruments to measure dimensions of self-efficacy, self-regulation, social support, outcome expectations, the physical environment, and minutes of MVPA per week. Spearman Rank Correlations were used to determine the relationship between SCT variables and MVPA. Classification and Regression Analysis using a decision tree model was used to determine the amount of variance in MVPA explained by SCT variables. Due to low levels of vigorous activity, only moderate-intensity exercise (MIE) was analyzed. SCT variables explained 42.4% of the variance in MIE. Self-monitoring, social support from family, social support from friends, and self-evaluative outcome expectations all contributed to the variability in MIE. Other contributing variables included self-reward, task self-efficacy, social outcome expectations, overcoming barriers, and self-efficacy for making time for exercise. SCT is a useful theory for identifying correlates of MIE among adults with type 2 diabetes. The SCT correlates can be used to refine diabetes education programs to target the adoption and maintenance of regular exercise.

  14. Treating NAFLD in OLETF Rats with Vigorous-Intensity Interval Exercise Training

    PubMed Central

    Linden, Melissa A.; Fletcher, Justin A.; Morris, E. Matthew; Meers, Grace M.; Laughlin, M. Harold; Booth, Frank W.; Sowers, James R.; Ibdah, Jamal A.; Thyfault, John P.; Rector, R. Scott

    2014-01-01

    Background There is increasing use of high intensity, interval type exercise training in the management of many lifestyle-related diseases. Purpose To test the hypothesis that vigorous-intensity, interval exercise is as effective as traditional, moderate-intensity aerobic exercise training on nonalcoholic fatty liver disease (NAFLD) outcomes in obese, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Methods OLETF rats (age 20 wks; n= 8–10/group) were assigned to sedentary (O-SED), moderate-intensity exercise training (O-MOD EX; 20 meters/min, 15% incline, 60 min/d, 5 d/wk treadmill running), or vigorous-intensity interval exercise training (O-VIG EX; 40 meters/min, 15% incline, 6×2.5 min bouts/d, 5 d/wk treadmill running) groups for 12 weeks. Results Both MOD EX and VIG EX effectively lowered hepatic triglycerides (TGs), serum ALTs, perivenular fibrosis, and hepatic collagen 1α1 mRNA expression (vs. O-SED, p<0.05). In addition, both interventions increased hepatic mitochondrial markers (citrate synthase activity and fatty acid oxidation) and suppressed markers of de novo lipogenesis (FAS, ACC, Elovl6, and SCD-1); whereas, only MOD EX increased hepatic mitochondrial β-HAD activity and hepatic TG export marker apoB100 and lowered fatty acid transporter CD36 compared with O-SED. Moreover, while total hepatic macrophage population markers (CD68 and F4/80 mRNA) did not differ among groups, MOD EX and VIG EX lowered M1 macrophage polarization markers (CD11c, IL-1β, and TNFα mRNA) and MOD EX increased M2 macrophage marker, CD206 mRNA, compared with O-SED. Conclusions The accumulation of 15 min/day of VIG EX for 12 weeks had similar effectiveness as 60 min/day of MOD EX in the management of NAFLD in OLETF rats. These findings may have important health outcome implications as we work to design better exercise training programs for NAFLD patients. PMID:24983336

  15. Hippocampal-Brainstem Connectivity Associated with Vagal Modulation after an Intense Exercise Intervention in Healthy Men

    PubMed Central

    Bär, Karl-Jürgen; Herbsleb, Marco; Schumann, Andy; de la Cruz, Feliberto; Gabriel, Holger W.; Wagner, Gerd

    2016-01-01

    Regular physical exercise leads to increased vagal modulation of the cardiovascular system. A combination of peripheral and central processes has been proposed to underlie this adaptation. However, specific changes in the central autonomic network have not been described in human in more detail. We hypothesized that the anterior hippocampus known to be influenced by regular physical activity might be involved in the development of increased vagal modulation after a 6 weeks high intensity intervention in young healthy men (exercise group: n = 17, control group: n = 17). In addition to the determination of physical capacity before and after the intervention, we used resting state functional magnetic resonance imaging and simultaneous heart rate variability assessment. We detected a significant increase of the power output at the anaerobic threshold of 11.4% (p < 0.001), the maximum power output Pmax of 11.2% (p < 0.001), and VO2max adjusted for body weight of 4.7% (p < 0.001) in the exercise group (EG). Comparing baseline (T0) and post-exercise (T1) values of parasympathetic modulation of the exercise group, we observed a trend for a decrease in heart rate (p < 0.06) and a significant increase of vagal modulation as indicated by RMSSD (p < 0.026) during resting state. In the whole brain analysis, we found that the connectivity pattern of the right anterior hippocampus (aHC) was specifically altered to the ventromedial anterior cortex, the dorsal striatum and to the dorsal vagal complex (DVC) in the brainstem. Moreover, we observed a highly significant negative correlation between increased RMSSD after exercise and decreased functional connectivity from the right aHC to DVC (r = −0.69, p = 0.003). This indicates that increased vagal modulation was associated with functional connectivity between aHC and the DVC. In conclusion, our findings suggest that exercise associated changes in anterior hippocampal function might be involved in increased vagal modulation. PMID

  16. High-intensity exercise of short duration alters bovine bone density and shape.

    PubMed

    Hiney, K M; Nielsen, B D; Rosenstein, D; Orth, M W; Marks, B P

    2004-06-01

    The ability of short-duration high-intensity exercise to stimulate bone formation in confinement was investigated using immature Holstein bull calves as a model. Eighteen bull calves, 8 wk of age, were assigned to one of three treatment groups: 1) group-housed (GR, which served as a control), 2) confined with no exercise (CF), or 3) confined with exercise (EX). The exercise protocol consisted of running 50 m on a concrete surface once daily, 5 d/wk. Confined calves remained stalled for the 42-d duration of the trial. Blood samples were taken to analyze concentrations of osteocalcin and deoxypyridinoline, markers of bone formation and resorption. At the completion of the trial, calves were humanely killed, and both forelegs were collected. The fused third and fourth metacarpal bone was scanned using computed tomography for determination of cross-sectional geometry and bone mineral density. Three-point bending tests to failure were performed on metacarpal bones. The exercise protocol resulted in the formation of a rounder bone in EX as well as in increased dorsal cortex thickness compared with those in the GR and CF. The exercised calves had a significantly smaller medullary cavity than CF and GR (P < 0.01) and a larger percentage of cortical bone area than CF (P < 0.01). Dorsal, palmar, and total bone mineral density was greater in EX than in CF (P < 0.05), and palmar and total bone mineral densities were greater (P < 0.05) in EX than in GR. There was a trend for the bones of EX to have a higher fracture force than CF (P < 0.10). Osteocalcin concentrations normalized from d 0 were higher in EX than CF (P < 0.05). Therefore, the exercise protocol altered bone shape and seemed to increase bone formation comparison with the stalled and group-housed calves. PMID:15216986

  17. Effects of an acute bout of moderate-intensity exercise on postprandial lipemia and airway inflammation.

    PubMed

    Johnson, Ariel M; Kurti, Stephanie P; Smith, Joshua R; Rosenkranz, Sara K; Harms, Craig A

    2016-03-01

    A high-fat meal (HFM) induces an increase in blood lipids (postprandial lipemia; PPL), systemic inflammation, and acute airway inflammation. While acute exercise has been shown to have anti-inflammatory and lipid-lowering effects, it is unknown whether exercise prior to an HFM will translate to reduced airway inflammation post-HFM. Our purpose was to determine the effects of an acute bout of exercise on airway inflammation post-HFM and to identify whether any protective effect of exercise on airway inflammation was associated with a reduction in PPL or systemic inflammation. In a randomized cross-over study, 12 healthy, 18- to 29-year-old men (age, 23.0 ± 3.2 years; height, 178.9 ± 5.5 cm; weight, 78.5 ± 11.7 kg) consumed an HFM (1 g fat/1 kg body weight) 12 h following exercise (EX; 60 min at 60% maximal oxygen uptake) or without exercise (CON). Fractional exhaled nitric oxide (FENO; measure of airway inflammation), triglycerides (TG), and inflammatory markers (high-sensitivity C-reactive protein, tumor-necrosis factor-alpha, and interleukin-6) were measured while fasted at 2 h and 4 h post-HFM. FENO increased over time (2 h: CON, p = 0.001; EX, p = 0.002, but not by condition (p = 0.991). TG significantly increased 2 and 4 h post-HFM (p < 0.001), but was not significant between conditions (p = 0.256). Inflammatory markers did not significantly increase by time or condition (p > 0.05). There were no relationships between FENO and TG or systemic inflammatory markers for any time point or condition (p > 0.05). In summary, an acute bout of moderate-intensity exercise performed 12 h prior to an HFM did not change postprandial airway inflammation or lipemia in healthy, 18- to 29-year-old men. PMID:26872295

  18. Muscle recruitment patterns regulate physiological responses during exercise of the same intensity.

    PubMed

    Deschenes, M R; Kraemer, W J; McCoy, R W; Volek, J S; Turner, B M; Weinlein, J C

    2000-12-01

    On different days, 10 men performed 30-min sessions of cycling at 50-55% of their peak oxygen uptake (VO(2)); one at 40 rpm and another at 80 rpm. Rectal temperature, heart rate (HR), mean arterial pressure (MAP), plasma lactate, glucose, insulin, and cortisol were measured before exercise, during the 15th and 30th min of exercise, and at 5 and 10 min postexercise. Rating of perceived exertion (RPE) was assessed 15 and 30 min into exercise. Electromyography established cadence-specific different intensities of quadriceps activation during cycling. At minute 30 of exercise and 5 min postexercise, HR was significantly (P < 0.05) greater at 40 rpm than at 80 rpm. MAP remained elevated longer after the 40-rpm than after the 80-rpm bout. Similarly, exercise-induced increases in plasma lactate persisted longer after the 40-rpm bout. Cortisol levels were elevated only at 40 rpm. RPE was higher during the slower cadence. These data indicated that the more pronounced muscle activation pattern associated with pedaling at 40 rpm resulted in greater physiological and psychophysiological stress than that observed at 80 rpm even though VO(2) was the same.

  19. 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

  20. High- versus moderate-intensity aerobic exercise training effects on skeletal muscle of infarcted rats.

    PubMed

    Moreira, José B N; Bechara, Luiz R G; Bozi, Luiz H M; Jannig, Paulo R; Monteiro, Alex W A; Dourado, Paulo M; Wisløff, Ulrik; Brum, Patricia C

    2013-04-01

    Poor skeletal muscle performance was shown to strongly predict mortality and long-term prognosis in a variety of diseases, including heart failure (HF). Despite the known benefits of aerobic exercise training (AET) in improving the skeletal muscle phenotype in HF, the optimal exercise intensity to elicit maximal outcomes is still under debate. Therefore, the aim of the present study was to compare the effects of high-intensity AET with those of a moderate-intensity protocol on skeletal muscle of infarcted rats. Wistar rats underwent myocardial infarction (MI) or sham surgery. MI groups were submitted either to an untrained (MI-UNT); moderate-intensity (MI-CMT, 60% Vo(2)(max)); or matched volume, high-intensity AET (MI-HIT, intervals at 85% Vo(2)(max)) protocol. High-intensity AET (HIT) was superior to moderate-intensity AET (CMT) in improving aerobic capacity, assessed by treadmill running tests. Cardiac contractile function, measured by echocardiography, was equally improved by both AET protocols. CMT and HIT prevented the MI-induced decay of skeletal muscle citrate synthase and hexokinase maximal activities, and increased glycogen content, without significant differences between protocols. Similar improvements in skeletal muscle redox balance and deactivation of the ubiquitin-proteasome system were also observed after CMT and HIT. Such intracellular findings were accompanied by prevented skeletal muscle atrophy in both MI-CMT and MI-HIT groups, whereas no major differences were observed between protocols. Taken together, our data suggest that despite superior effects of HIT in improving functional capacity, skeletal muscle adaptations were remarkably similar among protocols, leading to the conclusion that skeletal myopathy in infarcted rats was equally prevented by either moderate-intensity or high-intensity AET.

  1. Acute molecular responses to concurrent resistance and high-intensity interval exercise in untrained skeletal muscle.

    PubMed

    Pugh, Jamie K; Faulkner, Steve H; Jackson, Andrew P; King, James A; Nimmo, Myra A

    2015-04-01

    Concurrent training involving resistance and endurance exercise may augment the benefits of single-mode training for the purpose of improving health. However, muscle adaptations, associated with resistance exercise, may be blunted by a subsequent bout of endurance exercise, via molecular interference. High-intensity interval training (HIIT), generating similar adaptations to endurance exercise, may offer an alternative exercise mode to traditional endurance exercise. This study examined the influence of an acute HIIT session on the molecular responses following resistance exercise in untrained skeletal muscle. Ten male participants performed resistance exercise (4 × 8 leg extensions, 70% 1RM, (RE)) or RE followed by HIIT (10 × 1 min at 90% HRmax, (RE+HIIT)). Muscle biopsies were collected from the vastus lateralis before, 2 and 6 h post-RE to determine intramuscular protein phosphorylation and mRNA responses. Phosphorylation of Akt (Ser(473)) decreased at 6 h in both trials (P < 0.05). Phosphorylation of mTOR (Ser(2448)) was higher in RE+HIIT (P < 0.05). All PGC-1α mRNA variants increased at 2 h in RE+HIIT with PGC-1α and PGC-1α-ex1b remaining elevated at 6 h, whereas RE-induced increases at 2 and 6 h for PGC-1α-ex1b only (P < 0.05). Myostatin expression decreased at 2 and 6 h in both trials (P < 0.05). MuRF-1 was elevated in RE+HIIT versus RE at 2 and 6 h (P < 0.05). Atrogin-1 was lower at 2 h, with FOXO3A downregulated at 6 h (P < 0.05). These data do not support the existence of an acute interference effect on protein signaling and mRNA expression, and suggest that HIIT may be an alternative to endurance exercise when performed after resistance exercise in the same training session to optimize adaptations.

  2. A novel method to determine the electron temperature and density from the absolute intensity of line and continuum emission: application to atmospheric microwave induced Ar plasmas

    NASA Astrophysics Data System (ADS)

    Iordanova, E.; Palomares, J. M.; Gamero, A.; Sola, A.; van der Mullen, J. J. A. M.

    2009-08-01

    An absolute intensity measurement (AIM) technique is presented that combines the absolute measurements of the line and the continuum emitted by strongly ionizing argon plasmas. AIM is an iterative combination of the absolute line intensity-collisional radiative model (ALI-CRM) and the absolute continuum intensity (ACI) method. The basis of ALI-CRM is that the excitation temperature T13 determined by the method of ALI is transformed into the electron temperature Te using a CRM. This gives Te as a weak function of electron density ne. The ACI method is based on the absolute value of the continuum radiation and determines the electron density in a way that depends on Te. The iterative combination gives ne and Te. As a case study the AIM method is applied to plasmas created by torche à injection axiale (TIA) at atmospheric pressure and fixed frequency at 2.45 GHz. The standard operating settings are a gas flow of 1 slm and a power of 800 W; the measurements have been performed at a position of 1 mm above the nozzle. With AIM we found an electron temperature of 1.2 eV and electron density values around 1021 m-3. There is not much dependence of these values on the plasma control parameters (power and gas flow). From the error analysis we can conclude that the determination of Te is within 7% and thus rather accurate but comparison with other studies shows strong deviations. The ne determination comes with an error of 40% but is in reasonable agreement with other experimental results.

  3. Effect of β-alanine supplementation on high-intensity exercise performance.

    PubMed

    Harris, Roger C; Stellingwerff, Trent

    2013-01-01

    Carnosine is a dipeptide of β-alanine and L-histidine found in high concentrations in skeletal muscle. Combined with β-alanine, the pKa of the histidine imidazole ring is raised to ∼6.8, placing it within the muscle intracellular pH high-intensity exercise transit range. Combination with β-alanine renders the dipeptide inert to intracellular enzymic hydrolysis and blocks the histidinyl residue from participation in proteogenesis, thus making it an ideal, stable intracellular buffer. For vegetarians, synthesis is limited by β-alanine availability; for meat-eaters, hepatic synthesis is supplemented with β-alanine from the hydrolysis of dietary carnosine. Direct oral β-alanine supplementation will compensate for low meat and fish intake, significantly raising the muscle carnosine concentration. This is best achieved with a sustained-release formulation of β-alanine to avoid paresthesia symptoms and decreasing urinary spillover. In humans, increased levels of carnosine through β-alanine supplementation have been shown to increase exercise capacity and performance of several types, particularly where the high-intensity exercise range is 1-4 min. β-Alanine supplementation is used by athletes competing in high-intensity track and field cycling, rowing, swimming events and other competitions.

  4. Effect of β-alanine supplementation on high-intensity exercise performance.

    PubMed

    Harris, Roger C; Stellingwerff, Trent

    2013-01-01

    Carnosine is a dipeptide of β-alanine and L-histidine found in high concentrations in skeletal muscle. Combined with β-alanine, the pKa of the histidine imidazole ring is raised to ∼6.8, placing it within the muscle intracellular pH high-intensity exercise transit range. Combination with β-alanine renders the dipeptide inert to intracellular enzymic hydrolysis and blocks the histidinyl residue from participation in proteogenesis, thus making it an ideal, stable intracellular buffer. For vegetarians, synthesis is limited by β-alanine availability; for meat-eaters, hepatic synthesis is supplemented with β-alanine from the hydrolysis of dietary carnosine. Direct oral β-alanine supplementation will compensate for low meat and fish intake, significantly raising the muscle carnosine concentration. This is best achieved with a sustained-release formulation of β-alanine to avoid paresthesia symptoms and decreasing urinary spillover. In humans, increased levels of carnosine through β-alanine supplementation have been shown to increase exercise capacity and performance of several types, particularly where the high-intensity exercise range is 1-4 min. β-Alanine supplementation is used by athletes competing in high-intensity track and field cycling, rowing, swimming events and other competitions. PMID:23899755

  5. Does aerobic exercise intensity affect health-related parameters in overweight women?

    PubMed

    Botero, João P; Prado, Wagner L; Guerra, Ricardo L F; Speretta, Guilherme F F; Leite, Richard D; Prestes, Jonato; Sanz, Adrián V; Lyons, Scott; de Azevedo, Paulo H S M; Baldissera, Vilmar; Perez, Sergio E A; Dâmaso, Ana; da Silva, Rozinaldo G

    2014-03-01

    The aim of this study was to compare the effect of a cycling training programme performed at intensity corresponding to the lowest value of the respiratory quotient (RQ) versus at intensity corresponding to the ventilatory threshold (VT), on body composition and health-related parameters in overweight women. Thirty-two sedentary obese women (27-42 years old) were studied in a randomized trial of either RQ (n = 17) or VT (n = 15). RQ and VT training sessions were equalized by time (60 min) and performed in a cycloergometer. Anthropometry, body composition, lipid profile, glucose, basal metabolic rate (BMR) and fitness (maximal oxygen uptake) were evaluated before and after 12 weeks of intervention. Body weight, body mass index, fatness and fitness were improved in both groups (P<0·001). Triglycerides (TG) levels decreased only in response to RQ (P<0·001) and fat-free mass (FFM) to VT (P = 0·002). No differences were observed between groups. Both exercise intensities seem to be effective for improving health in overweight women. However, low-intensity compared with the high-intensity exercise training appears to have additional benefits on TG levels and to maintenance of FFM.

  6. Effects of high-intensity intermittent running exercise in overweight children.

    PubMed

    Lau, Patrick W C; Wong, Del P; Ngo, Jake K; Liang, Y; Kim, C G; Kim, H S

    2015-01-01

    This study examined the effects of a 6-week intermittent exercise training, at different intensities, on body composition, functional walking and aerobic endurance in overweight children. Forty-eight overweight children (age: 10.4 ± 0.9 years) were randomly assigned to either intervention or control group. Lower and higher intensity intermittent exercise groups (LIIE and HIIE) performed intermittent running three times a week. LIIE performed more intervals at a lower intensity [16 intervals at 100% of individual maximal aerobic speed (MAS), 8 minutes in total], and HIIE performed fewer intervals at a higher intensity (12 intervals at 120% of MAS, 6 minutes in total). Each interval consisted of a 15-second run at the required speed, followed by a 15-second passive recovery. After 6 weeks, HIIE had a significantly (p < 0.05) higher percentage reduction in sum of skinfolds (i.e. calf and triceps), and significantly (p < 0.05) fewer steps during the functional obstacle performance, as compared with LIIE and control group. Significant improvement (p < 0.05) was found in intermittent aerobic endurance for HIIE as compared to the control group. Higher intensity intermittent training is an effective and time-efficient intervention for improving body composition, functional walking and aerobic endurance in overweight children. PMID:25012183

  7. Effects of High-Intensity Endurance Exercise on Epidermal Barriers against Microbial Invasion

    PubMed Central

    Eda, Nobuhiko; Shimizu, Kazuhiro; Suzuki, Satomi; Lee, Eunjae; Akama, Takao

    2013-01-01

    For athletes, preventing infectious disease on skin is important. Examination measurement of epidermal barriers could provide valuable information on the risk of skin infections. The aim of this study was to determine the effects of high-intensity endurance exercise on epidermal barriers. Six healthy adult males (age; 22.3 ± 1.6 years) performed bicycle exercise at 75%HRmax for 60 min from 18:30 to 19:30. Skin surface samples were measured 18:30 (pre), 19:30 (post), 20:30 (60 min), and 21:30 (120 min). Secretory immunoglobulin A (SIgA) and human β-defensin 2 (HBD-2) concentrations were measured using an enzyme-linked immunosorbent assay (ELISA). SIgA concentration at pre was significantly higher than at post, 60 min and 120 min (p < 0.05). HBD-2 concentration at post and 120 min was significantly higher than at pre (p < 0. 05). Moisture content of the stratum corneum was significantly higher at post than at pre, 60 min, and 120 min (p < 0.05). On the chest, moisture content of the stratum corneum was significantly lower at 120 min than at pre (p < 0.05). The number of staphylococci was significantly higher at post than at pre (p < 0.05), and tended to be higher at 60 min than at pre on the chest (p = 0. 08). High-intensity endurance exercise might depress the immune barrier and physical barrier and enhance the risk of skin infection. On the other hand, the biochemical barrier increases after exercise, and our findings suggest that this barrier might supplement the compromised function of other skin barriers. Key points The immune barrier and physical barrier might be depressed and the risk of skin infection might be enhanced by high-intensity endurance exercise. The biochemical barrier increases after high-intensity endurance exercise and might supplement the compromised function of other skin barriers. We recommend that athletes maintain their skin surface in good condition, for example, by showering immediately after sports activities and using moisturizers

  8. Hyperthermia, but not muscle water deficit, increases glycogen use during intense exercise.

    PubMed

    Fernández-Elías, V E; Hamouti, N; Ortega, J F; Mora-Rodríguez, R

    2015-06-01

    We determined if dehydration alone or in combination with hyperthermia accelerates muscle glycogen use during intense exercise. Seven endurance-trained cyclists (VO2max  = 54.4 ± 1.05 mL/kg/min) dehydrated 4.6% of body mass (BM) during exercise in the heat (150 min at 33 ± 1 °C, 25 ± 2% humidity). During recovery (4 h), subjects remained dehydrated (HYPO trial) or recovered all fluid losses (REH trials). Finally, subjects exercised intensely (75% VO2max ) for 40 min in a neutral (25 ± 1 °C; HYPO and REH trials) or in a hot environment (36 ± 1 °C; REHHOT ). Before the final exercise bout vastus lateralis glycogen concentration was similar in all three trials (434 ± 57 mmol/kg of dry muscle (dm)) but muscle water content was lower in the HYPO (357 ± 14 mL/100 g dm) than in REH trials (389 ± 25 and 386 ± 25 mL/100 g dm; P < 0.05). After 40 min of intense exercise, intestinal temperature was similar between the HYPO and REHHOT trials (39.2 ± 0.5 and 39.2 ± 0.4 °C, respectively) and glycogen use was similar (172 ± 86 and 185 ± 97 mmol/kg dm, respectively) despite large differences in muscle water content. In contrast, during REH, intestinal temperature (38.5 ± 0.4 °C) and glycogen use (117 ± 52 mmol/kg dm) were significantly lower than during HYPO and REHHOT . Our data suggest that hyperthermia stimulates glycogen use during intense exercise while muscle water deficit has a minor role.

  9. Effect of motivational music on lactate levels during recovery from intense exercise.

    PubMed

    Eliakim, Michal; Bodner, Ehud; Eliakim, Alon; Nemet, Dan; Meckel, Yoav

    2012-01-01

    The effects of music played during an exercise task on athletic performance have been previously studied. Yet, these results are not applicable for competitive athletes, who can use music only during warm-up or recovery from exercise. Therefore, the aim of this study was to determine the effect of motivational music (music that stimulates or inspires physical activity) during recovery from intense exercise, on activity pattern, rate of perceived exertion (RPE), and blood lactate concentration. Twenty young, active men (mean age 26.2 ± 2.1 years) performed a 6-minute run at peak oxygen consumption speed (predetermined from the VO(2) max test). The mean heart rate (HR), RPE, number of steps (determined by step counter), and blood lactate concentrations were determined at 3, 6, 9, 12, and 15 minutes during the recovery from the exercise, with and without motivational music (2 separate sessions, at random order). There was no difference in the mean HR during the recovery with and without music. Listening to motivational music during the recovery was associated with increased voluntary activity of the participants, determined by increased number of steps (499.4 ± 220.1 vs. 413.2 ± 150.6 steps, with and without music, respectively; p ≤ 0.05). The increased number of steps during the recovery was accompanied by a significantly greater decrease in blood lactate concentration percentage (28.1 ± 12.2 vs. 22.8 ± 10.9%, with and without music, respectively, p ≤ 0.05). This was associated with a greater decrease in RPE (77.7 ± 14.4 vs. 73.1 ± 14.7% with and without music, respectively; p ≤ 0.05). Our results suggest that listening to motivational music during nonstructured recovery from intense exercise leads to increased activity, faster lactate clearance, and reduced RPE and therefore may be used by athletes in their effort to enhance recovery.

  10. Neuromuscular fatigue during high-intensity intermittent exercise in individuals with intellectual disability.

    PubMed

    Borji, Rihab; Sahli, Sonia; Zarrouk, Nidhal; Zghal, Firas; Rebai, Haithem

    2013-12-01

    This study examined neuromuscular fatigue after high-intensity intermittent exercise in 10 men with mild intellectual disability (ID) in comparison with 10 controls. Both groups performed three maximal voluntary contractions (MVC) of knee extension with 5 min in-between. The highest level achieved was selected as reference MVC. The fatiguing exercise consists of five sets with a maximal number of flexion-extension cycles at 80% of the one maximal repetition (1RM) for the right leg at 90° with 90 s rest interval between sets. The MVC was tested again after the last set. Peak force and electromyography (EMG) signals were measured during the MVC tests. Root Mean Square (RMS) and Median Frequency (MF) were calculated. Neuromuscular efficiency (NME) was calculated as the ratio of peak force to the RMS. Before exercise, individuals with ID had a lower MVC (p<0.05) and a lower RMS (p<0.05). No significant difference between groups in MF and NME. After exercise, MVC decreases significantly in both groups (p<0.001). Individuals with ID have greater force decline (p<0.001 vs. p<0.01). RMS decreased significantly (p<0.001) whereas the NME increased significantly (p<0.05) in individuals with ID, but both remained unchanged in controls. The MF decreased significantly in both groups (p<0.001). In conclusion, individuals with ID presented a lower peak force than individuals without ID. After a high-intensity intermittent exercise, individuals with ID demonstrated a greater force decline caused by neural activation failure. When rehabilitation and sport train ID individuals, they should consider this nervous system weakness.

  11. Physical performance during high-intensity resistance exercise in normoxic and hypoxic conditions.

    PubMed

    Scott, Brendan R; Slattery, Katie M; Sculley, Dean V; Hodson, Jacob A; Dascombe, Ben J

    2015-03-01

    This study aimed to determine whether different levels of hypoxia affect physical performance during high-intensity resistance exercise or subsequent cardiovascular and perceptual responses. Twelve resistance-trained young men (age, 25.3 ± 4.3 years; height, 179.0 ± 4.5 cm; body mass, 83.4 ± 9.1 kg) were tested for 1 repetition maximum (1RM) in the back squat and deadlift. Following this, participants completed 3 separate randomized trials of 5 × 5 repetitions at 80% 1RM, with 3 minutes rest between sets, in normoxia (NORM; fraction of inspired oxygen [FIO2] = 0.21), moderate-level hypoxia (FIO2 = 0.16), or high-level hypoxia (FIO2 = 0.13) by a portable hypoxic unit. Peak and mean force and power variables were monitored during exercise. Arterial oxygen saturation (SpO2), heart rate (HR), and rating of perceived exertion (RPE) were assessed immediately following each set. No differences in force or power variables were evident between conditions. Similar trends were evident in these variables across each set and across the exercise session in each condition. SpO2 was lower in hypoxic conditions than in NORM, whereas HR was higher following sets performed in hypoxia. There were no differences between conditions in RPE. These results indicate that a hypoxic stimulus during high-intensity resistance exercise does not alter physical performance during repetitions and sets or affect how strenuous exercise is perceived to be. This novel training strategy can be used without adversely affecting the physical training dose experienced and may provide benefits over the equivalent training in NORM. PMID:25226332

  12. Self-pacing increases critical power and improves performance during severe-intensity exercise.

    PubMed

    Black, Matthew I; Jones, Andrew M; Bailey, Stephen J; Vanhatalo, Anni

    2015-07-01

    The parameters of the power-duration relationship for severe-intensity exercise (i.e., the critical power (CP) and the curvature constant (W')) are related to the kinetics of pulmonary O2 uptake, which may be altered by pacing strategy. We tested the hypothesis that the CP would be higher when derived from a series of self-paced time-trials (TT) than when derived from the conventional series of constant work-rate (CWR) exercise tests. Ten male subjects (age, 21.5 ± 1.9 years; mass, 75.2 ± 11.5 kg) completed 3-4 CWR and 3-4 TT prediction trial protocols on a cycle ergometer for the determination of the CP and W'. The CP derived from the TT protocol (265 ± 44 W) was greater (P < 0.05) than the CP derived from the CWR protocol (250 ± 47 W), while the W' was not different between protocols (TT: 18.1 ± 5.7 kJ, CWR: 20.6 ± 7.4 kJ, P > 0.05). The mean response time of pulmonary O2 uptake was shorter during the TTs than the CWR trials (TT: 34 ± 16, CWR: 39 ± 19 s, P < 0.05). The CP was correlated with the total O2 consumed in the first 60 s across both protocols (r = 0.88, P < 0.05, n = 20). These results suggest that in comparison with the conventional CWR exercise protocol, a self-selected pacing strategy enhances CP and improves severe-intensity exercise performance. The greater CP during TT compared with CWR exercise has important implications for performance prediction, suggesting that TT completion times may be overestimated by CP and W' parameters derived from CWR protocols.

  13. Reliability of a Novel High Intensity One Leg Dynamic Exercise Protocol to Measure Muscle Endurance

    PubMed Central

    Lepers, Romuald; Marcora, Samuele M.

    2016-01-01

    We recently developed a high intensity one leg dynamic exercise (OLDE) protocol to measure muscle endurance and investigate the central and peripheral mechanisms of muscle fatigue. The aims of the present study were to establish the reliability of this novel protocol and describe the isokinetic muscle fatigue induced by high intensity OLDE and its recovery. Eight subjects performed the OLDE protocol (time to exhaustion test of the right leg at 85% of peak power output) three times over a week period. Isokinetic maximal voluntary contraction torque at 60 (MVC60), 100 (MVC100) and 140 (MVC140) deg/s was measured pre-exercise, shortly after exhaustion (13 ± 4 s), 20 s (P20) and 40 s (P40) post-exercise. Electromyographic (EMG) signal was analyzed via the root mean square (RMS) for all three superficial knee extensors. Mean time to exhaustion was 5.96 ± 1.40 min, coefficient of variation was 8.42 ± 6.24%, typical error of measurement was 0.30 min and intraclass correlation was 0.795. MVC torque decreased shortly after exhaustion for all angular velocities (all P < 0.001). MVC60 and MVC100 recovered between P20 (P < 0.05) and exhaustion and then plateaued. MVC140 recovered only at P40 (P < 0.05). High intensity OLDE did not alter maximal EMG RMS of the three superficial knee extensors during MVC. The results of this study demonstrate that this novel high intensity OLDE protocol could be reliably used to measure muscle endurance, and that muscle fatigue induced by high intensity OLDE should be examined within ~ 30 s following exhaustion. PMID:27706196

  14. Effect of low-intensity treadmill exercise on behavioural measures and hippocampal parvalbumin immunoreactivity in the rat.

    PubMed

    Nguyen, Jason C D; Killcross, A Simon; Jenkins, Trisha A

    2013-11-01

    Exercise has been demonstrated to have positive effects on both the body and brain. The present study aimed to determine the behavioural and morphological consequence of low-intensity running. Rats were exercised on a treadmill for a total of 30 days, 30 min/day. Social interaction, locomotor activity and behaviour on an elevated plus maze were assessed post-treatment. Exercised animals demonstrated more passive interaction and less time not interacting than control animals that were not exercised. Conversely, locomotor and anxiety measures showed no effect of exercise. Analysis of brains demonstrated an increase in expression of parvalbumin immunoreactive neurons in the hippocampus localised to the CA1 and CA2/3 regions. These results demonstrate that low-intensity exercise leads to changes in social behaviour as well as neuroplastic morphological changes within the hippocampus.

  15. Easy Absolute Values? Absolutely

    ERIC Educational Resources Information Center

    Taylor, Sharon E.; Mittag, Kathleen Cage

    2015-01-01

    The authors teach a problem-solving course for preservice middle-grades education majors that includes concepts dealing with absolute-value computations, equations, and inequalities. Many of these students like mathematics and plan to teach it, so they are adept at symbolic manipulations. Getting them to think differently about a concept that they…

  16. The effects of mouthpiece use on cortisol levels during an intense bout of resistance exercise.

    PubMed

    Garner, Dena P; Dudgeon, Wesley D; McDivitt, Erica J

    2011-10-01

    Research has suggested mouthpiece use during exercise results in an increase in muscle strength and endurance. However, the research is difficult to replicate, and the methodology suggested measures that were too subjective to determine a mouthpiece effect. Thus, the purpose of this study was to use an objective measure to determine a possible physiological mechanism occurring during and after exercise with mouthpiece use. A within-subjects design was used in which 28 division I football players, aged 18-22 years, performed 2 identical bouts of a 1-hour intense resistance exercise, with each subject being randomly assigned the use of a custom-fit mouthpiece either during the first or second session. During both exercise sessions, saliva was analyzed for cortisol at the following time points: pre-exercise, 25, 45, and 60 minutes of exercise, and 10 minutes postexercise. The results revealed a significant difference in cortisol levels with the use of a mouthpiece vs. no mouthpiece (p = 0.019) at 10 minutes postexercise. Additionally, although the expected increase in cortisol levels from pre to 10 minutes postexercise was present in the no-mouthpiece group (p = 0.01), no such increase was observed in the mouthpiece group. These observations are most likely because of the decrease in cortisol from post to 10 minutes post (p = 0.04) in the mouthpiece group. These data demonstrate that although cortisol continued to increase in the no-mouthpiece session, there was a significant decrease in cortisol in the no-mouthpiece condition 10 minutes postexercise.

  17. Nutritional Strategies to Modulate Intracellular and Extracellular Buffering Capacity During High-Intensity Exercise.

    PubMed

    Lancha Junior, Antonio Herbert; Painelli, Vitor de Salles; Saunders, Bryan; Artioli, Guilherme Giannini

    2015-11-01

    Intramuscular acidosis is a contributing factor to fatigue during high-intensity exercise. Many nutritional strategies aiming to increase intra- and extracellular buffering capacity have been investigated. Among these, supplementation of beta-alanine (~3-6.4 g/day for 4 weeks or longer), the rate-limiting factor to the intramuscular synthesis of carnosine (i.e. an intracellular buffer), has been shown to result in positive effects on exercise performance in which acidosis is a contributing factor to fatigue. Furthermore, sodium bicarbonate, sodium citrate and sodium/calcium lactate supplementation have been employed in an attempt to increase the extracellular buffering capacity. Although all attempts have increased blood bicarbonate concentrations, evidence indicates that sodium bicarbonate (0.3 g/kg body mass) is the most effective in improving high-intensity exercise performance. The evidence supporting the ergogenic effects of sodium citrate and lactate remain weak. These nutritional strategies are not without side effects, as gastrointestinal distress is often associated with the effective doses of sodium bicarbonate, sodium citrate and calcium lactate. Similarly, paresthesia (i.e. tingling sensation of the skin) is currently the only known side effect associated with beta-alanine supplementation, and it is caused by the acute elevation in plasma beta-alanine concentration after a single dose of beta-alanine. Finally, the co-supplementation of beta-alanine and sodium bicarbonate may result in additive ergogenic gains during high-intensity exercise, although studies are required to investigate this combination in a wide range of sports.

  18. Effects of exercise intensity on postexercise hypotension after resistance training session in overweight hypertensive patients.

    PubMed

    Cavalcante, Paula Andréa M; Rica, Roberta L; Evangelista, Alexandre L; Serra, Andrey J; Figueira, Aylton; Pontes, Francisco Luciano; Kilgore, Lon; Baker, Julien S; Bocalini, Danilo S

    2015-01-01

    Among all nonpharmacological treatments, aerobic or resistance training (RT) has been indicated as a significantly important strategy to control hypertension. However, postexercise hypotension responses after intensity alterations in RT are not yet fully understood. The purpose of this study was to compare the outcomes of differing intensities of RT on hypertensive older women. Twenty hypertensive older women participated voluntarily in this study. After a maximum voluntary contraction test (one repetition maximum) and determination of 40% and 80% experimental loads, the protocol (3 sets/90″ interset rest) was performed in a single session with the following exercises: leg press, leg extension, leg curl, chest press, elbow flexion, elbow extension, upper back row, and abdominal flexion. Systolic and diastolic blood pressures were evaluated at rest, during exercise peak, and after 5, 10, 15, 30, 45, and 60 minutes of exercise and compared to the control. Both experimental loads were effective (P<0.01) in promoting postexercise systolic hypotension (mmHg) compared to controls, after 30, 45, and 60 minutes, respectively, at 40% (113±2, 112±4, and 110±3 mmHg) and 80% (111±3, 111±4, and 110±4 mmHg). Both procedures promoted hypotension with similar systolic blood pressures (40%: -11%±1.0% and 80%: -13%±0.5%), mean arterial blood pressures (40%: -12%±5.5% and 80%: -12%±3.4%), and rate-pressure products (40%: -15%±2.1% and 80%: -17%±2.4%) compared to control measures (systolic blood pressure: 1%±1%, mean arterial blood pressure:\\ 0.6%±1.5%, rate-pressure product: 0.33%±1.1%). No differences were found in diastolic blood pressure and heart rate measures. In conclusion, hypertensive older women exhibit postexercise hypotension independently of exercise intensity without expressed cardiovascular overload during the session. PMID:26425078

  19. Raman intensities of liquids: Absolute scattering activities and electro-optical parameters (EOPs) of arsenate and selenate ions in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Eysel, Hans H.; Wagner, Rüdiger

    1993-04-01

    Absolute Raman scattering activities of aqueous solutions of sodium arsenate and sodium selenate have been measured against NaClO 4 as an external standard. Electro-optical parameters (EOPs) for the AsO and SeO bonds were calculated. Changes of the previously published force fields (GVFF) were necessary to adjust the eigenvectors to the experimental frequencies and intensities in aqueous environment. Equilibrium bond polarizabilities were estimated from refractive index measurements in connection with Raman intensities of bending modes. The EOPs of these two isoelectronic compounds are discussed in comparison with the series phosphate, sulphate, perchlorate.

  20. Abnormal EKG stress test in rats with type 1 diabetes is deterred with low-intensity exercise programme.

    PubMed

    Smirnova, I V; Kibiryeva, N; Vidoni, E; Bunag, R; Stehno-Bittel, L

    2006-11-01

    The focus of this study was to determine whether minimal levels of exercise could halt the formation of diabetes-induced heart pathology. Seven-week-old male rats were divided into four groups: sedentary nondiabetic, exercise-trained non-diabetic, sedentary diabetic and exercise-trained diabetic. Individualised exercise programmes were based on the animal's tolerance, and continued for 7 weeks after the induction of diabetes. At the completion of the study, no differences were found in skeletal muscle citrate synthase activity between diabetic sedentary and exercise-trained rats, indicating that the exercise was low intensity. Diabetes-induced heart hypertrophy was not reversed with exercise as measured by heart-to-body weight ratios and EKG (R wave height). There was no statistical difference between groups in the response to an exercise stress test prior to the induction of diabetes. However, 4 weeks of diabetes resulted in a significant decrease in resting and post-stress test heart rates (9% and 20%, respectively), which remained depressed at week 7. The sedentary diabetic animals demonstrated an abnormal response during the recovery period of the EKG exercise test, which was not present in non-diabetic or exercise-trained diabetic animals. In conclusion, lowintensity exercise training improved the cardiac response to an exercise stress test in diabetic animals.

  1. Differential Effects of Differing Intensities of Acute Exercise on Speed and Accuracy of Cognition: A Meta-Analytical Investigation

    ERIC Educational Resources Information Center

    McMorris, Terry; Hale, Beverley J.

    2012-01-01

    The primary purpose of this study was to examine, using meta-analytical techniques, the differential effects of differing intensities of acute exercise on speed and accuracy of cognition. Overall, exercise demonstrated a small, significant mean effect size (g = 0.14, p less than 0.01) on cognition. Examination of the comparison between speed and…

  2. Muscle soreness, swelling, stiffness and strength loss after intense eccentric exercise.

    PubMed

    Cleak, M J; Eston, R G

    1992-12-01

    High-intensity eccentric contractions induce performance decrements and delayed onset muscle soreness. The purpose of this investigation was to study the magnitude and time course of such decrements and their interrelationships in 26 young women of mean(s.d.) age 21.4(3.3) years. Subjects performed 70 maximal eccentric contractions of the elbow flexors on a pulley system, specially designed for the study. The non-exercised arm acted as the control. Measures of soreness, tenderness, swelling (SW), relaxed elbow joint angle (RANG) and isometric strength (STR) were taken before exercise, immediately after exercise (AE), analysis of variance and at 24-h intervals for 11 days. There were significant (P < 0.01, analysis of variance) changes in all factors. Peak effects were observed between 24 and 96 h AE. With the exception of STR, which remained lower (P < 0.01), all variables returned to baseline levels by day 11. A non-significant correlation between pain and STR indicated that pain was not a major factor in strength loss. Also, although no pain was evident, RANG was decreased immediately AE. There was no relationship between SW, RANG and pain. The prolonged nature of these symptoms indicates that repair to damaged soft tissue is a slow process. Strength loss is considered particularly important as it continues when protective pain and tenderness have disappeared. This has implications for the therapeutic management of patients with myopathologies and those receiving eccentric exercise for rehabilitation.

  3. 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. PMID:27688431

  4. 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.

  5. Ambulatory blood pressure reduction following high-intensity interval exercise performed in water or dryland condition.

    PubMed

    Sosner, Philippe; Gayda, Mathieu; Dupuy, Olivier; Garzon, Mauricio; Lemasson, Christopher; Gremeaux, Vincent; Lalongé, Julie; Gonzales, Mariel; Hayami, Douglas; Juneau, Martin; Nigam, Anil; Bosquet, Laurent

    2016-05-01

    We aimed to compare blood pressure (BP) responses following moderate-intensity continuous exercise (MICE), high-intensity interval exercise (HIIE) in dry land or HIIE in immersed condition, using 24-hour ambulatory BP monitoring. Forty-two individuals (65 ± 7 years, 52% men) with a baseline BP ≥ 130/85 mm Hg (systolic/diastolic blood pressures [SBP/DBP]) were randomly assigned to perform one of the three following exercises on a stationary cycle: MICE (24 minutes at 50% peak power output) or HIIE in dry land (two sets of 10 minutes with phases of 15 seconds 100% peak power output interspersed by 15 seconds of passive recovery) or HIIE in up-to-the-chest immersed condition. While MICE modified none of the 24-hour average hemodynamic variables, dryland HIIE induced a 24-hour BP decrease (SBP: -3.6 ± 5.7/DBP: -2.8 ± 3.0 mm Hg, P < .05) and, to a much greater extent, immersed HIIE (SBP: -6.8 ± 9.5/DBP: -3.0 ± 4.5 mm Hg, P < .05). The one condition that modified 24-hour pulse-wave velocity was immersed HIIE (-0.21 ± 0.30 m/s, P < .05).

  6. High-intensity interval training (HIT) for effective and time-efficient pre-surgical exercise interventions.

    PubMed

    Weston, Matthew; Weston, Kathryn L; Prentis, James M; Snowden, Chris P

    2016-01-01

    The advancement of perioperative medicine is leading to greater diversity in development of pre-surgical interventions, implemented to reduce patient surgical risk and enhance post-surgical recovery. Of these interventions, the prescription of pre-operative exercise training is gathering momentum as a realistic means for enhancing patient surgical outcome. Indeed, the general benefits of exercise training have the potential to pre-operatively optimise several pre-surgical risks factors, including cardiorespiratory function, frailty and cognitive function. Any exercise programme incorporated into the pre-operative pathway of care needs to be effective and time efficient in that any fitness gains are achievable in the limited period between the decision for surgery and operation (e.g. 4 weeks). Fortunately, there is a large volume of research describing effective and time-efficient exercise training programmes within the discipline of sports science. Accordingly, the objective of our commentary is to synthesise contemporary exercise training research, both from non-clinical and clinical populations, with the overarching aim of informing the development of effective and time-efficient pre-surgical exercise training programmes. The development of such exercise training programmes requires the careful consideration of several key principles, namely frequency, intensity, time, type and progression of exercise. Therefore, in light of more recent evidence demonstrating the effectiveness and time efficiency of high-intensity interval training-which involves brief bouts of intense exercise interspersed with longer recovery periods-the principles of exercise training programme design will be discussed mainly in the context of such high-intensity interval training programmes. Other issues pertinent to the development, implementation and evaluation of pre-operative exercise training programmes, such as individual exercise prescription, training session monitoring and potential

  7. High-intensity interval training (HIT) for effective and time-efficient pre-surgical exercise interventions.

    PubMed

    Weston, Matthew; Weston, Kathryn L; Prentis, James M; Snowden, Chris P

    2016-01-01

    The advancement of perioperative medicine is leading to greater diversity in development of pre-surgical interventions, implemented to reduce patient surgical risk and enhance post-surgical recovery. Of these interventions, the prescription of pre-operative exercise training is gathering momentum as a realistic means for enhancing patient surgical outcome. Indeed, the general benefits of exercise training have the potential to pre-operatively optimise several pre-surgical risks factors, including cardiorespiratory function, frailty and cognitive function. Any exercise programme incorporated into the pre-operative pathway of care needs to be effective and time efficient in that any fitness gains are achievable in the limited period between the decision for surgery and operation (e.g. 4 weeks). Fortunately, there is a large volume of research describing effective and time-efficient exercise training programmes within the discipline of sports science. Accordingly, the objective of our commentary is to synthesise contemporary exercise training research, both from non-clinical and clinical populations, with the overarching aim of informing the development of effective and time-efficient pre-surgical exercise training programmes. The development of such exercise training programmes requires the careful consideration of several key principles, namely frequency, intensity, time, type and progression of exercise. Therefore, in light of more recent evidence demonstrating the effectiveness and time efficiency of high-intensity interval training-which involves brief bouts of intense exercise interspersed with longer recovery periods-the principles of exercise training programme design will be discussed mainly in the context of such high-intensity interval training programmes. Other issues pertinent to the development, implementation and evaluation of pre-operative exercise training programmes, such as individual exercise prescription, training session monitoring and potential

  8. Matching of postcontraction perfusion to oxygen consumption across submaximal contraction intensities in exercising humans

    PubMed Central

    Elder, Christopher P.; Donahue, Manus J.; Damon, Bruce M.

    2015-01-01

    Studying the magnitude and kinetics of blood flow, oxygen extraction, and oxygen consumption at exercise onset and during the recovery from exercise can lead to insights into both the normal control of metabolism and blood flow and the disturbances to these processes in metabolic and cardiovascular diseases. The purpose of this study was to examine the on- and off-kinetics for oxygen delivery, extraction, and consumption as functions of submaximal contraction intensity. Eight healthy subjects performed four 1-min isometric dorsiflexion contractions, with two at 20% MVC and two at 40% MVC. During one contraction at each intensity, relative perfusion changes were measured by using arterial spin labeling, and the deoxyhemoglobin percentage (%HHb) was estimated using the spin- and gradient-echo sequence and a previously published empirical calibration. For the whole group, the mean perfusion did not increase during contraction. The %HHb increased from ∼28 to 38% during contractions of each intensity, with kinetics well described by an exponential function and mean response times (MRTs) of 22.7 and 21.6 s for 20 and 40% MVC, respectively. Following contraction, perfusion increased ∼2.5-fold. The %HHb, oxygen consumption, and perfusion returned to precontraction levels with MRTs of 27.5, 46.4, and 50.0 s, respectively (20% MVC), and 29.2, 75.3, and 86.0 s, respectively (40% MVC). These data demonstrate in human subjects the varied recovery rates of perfusion and oxygen consumption, along with the similar rates of %HHb recovery, across these exercise intensities. PMID:26066829

  9. Matching of postcontraction perfusion to oxygen consumption across submaximal contraction intensities in exercising humans.

    PubMed

    Buck, Amanda K W; Elder, Christopher P; Donahue, Manus J; Damon, Bruce M

    2015-08-01

    Studying the magnitude and kinetics of blood flow, oxygen extraction, and oxygen consumption at exercise onset and during the recovery from exercise can lead to insights into both the normal control of metabolism and blood flow and the disturbances to these processes in metabolic and cardiovascular diseases. The purpose of this study was to examine the on- and off-kinetics for oxygen delivery, extraction, and consumption as functions of submaximal contraction intensity. Eight healthy subjects performed four 1-min isometric dorsiflexion contractions, with two at 20% MVC and two at 40% MVC. During one contraction at each intensity, relative perfusion changes were measured by using arterial spin labeling, and the deoxyhemoglobin percentage (%HHb) was estimated using the spin- and gradient-echo sequence and a previously published empirical calibration. For the whole group, the mean perfusion did not increase during contraction. The %HHb increased from ∼28 to 38% during contractions of each intensity, with kinetics well described by an exponential function and mean response times (MRTs) of 22.7 and 21.6 s for 20 and 40% MVC, respectively. Following contraction, perfusion increased ∼2.5-fold. The %HHb, oxygen consumption, and perfusion returned to precontraction levels with MRTs of 27.5, 46.4, and 50.0 s, respectively (20% MVC), and 29.2, 75.3, and 86.0 s, respectively (40% MVC). These data demonstrate in human subjects the varied recovery rates of perfusion and oxygen consumption, along with the similar rates of %HHb recovery, across these exercise intensities.

  10. Motor effort training with low exercise intensity improves muscle strength and descending command in aging.

    PubMed

    Jiang, Changhao; Ranganathan, Vinoth K; Zhang, Junmei; Siemionow, Vlodek; Yue, Guang H

    2016-06-01

    This study explored the effect of high mental effort training (MET) and conventional strength training (CST) on increasing voluntary muscle strength and brain signal associated with producing maximal muscle force in healthy aging. Twenty-seven older adults (age: 75 ± 7.9 yr, 8 women) were assigned into 1 of 3 groups: MET group-trained with low-intensity (30% maximal voluntary contraction [MVC]) physical exercise combined with MET, CST group-trained with high-intensity muscle contractions, or control (CTRL) group-no training of any kind. MET and CST lasted for 12 weeks (5 sessions/week). The participants' elbow flexion strength of the right arm, electromyography (EMG), and motor activity-related cortical potential (MRCP) directly related to the strength production were measured before and after training. The CST group had the highest strength gain (17.6%, P <0.001), the MET group also had significant strength gain (13.8%, P <0.001), which was not statistically different from that of the CST group even though the exercise intensity for the MET group was only at 30% MVC level. The CTRL group did not have significant strength changes. Surprisingly, only the MET group demonstrated a significant augmentation in the MRCP (29.3%, P <0.001); the MRCP increase in CST group was at boarder-line significance level (12.11%, P = 0.061) and that for CTRL group was only 4.9% (P = 0.539). These results suggest that high mental effort training combined with low-intensity physical exercise is an effective method for voluntary muscle strengthening and this approach is especially beneficial for those who are physically weak and have difficulty undergoing conventional strength training.

  11. Motor effort training with low exercise intensity improves muscle strength and descending command in aging

    PubMed Central

    Jiang, Changhao; Ranganathan, Vinoth K.; Zhang, Junmei; Siemionow, Vlodek; Yue, Guang H.

    2016-01-01

    Abstract This study explored the effect of high mental effort training (MET) and conventional strength training (CST) on increasing voluntary muscle strength and brain signal associated with producing maximal muscle force in healthy aging. Twenty-seven older adults (age: 75 ± 7.9 yr, 8 women) were assigned into 1 of 3 groups: MET group—trained with low-intensity (30% maximal voluntary contraction [MVC]) physical exercise combined with MET, CST group—trained with high-intensity muscle contractions, or control (CTRL) group—no training of any kind. MET and CST lasted for 12 weeks (5 sessions/week). The participants’ elbow flexion strength of the right arm, electromyography (EMG), and motor activity-related cortical potential (MRCP) directly related to the strength production were measured before and after training. The CST group had the highest strength gain (17.6%, P <0.001), the MET group also had significant strength gain (13.8%, P <0.001), which was not statistically different from that of the CST group even though the exercise intensity for the MET group was only at 30% MVC level. The CTRL group did not have significant strength changes. Surprisingly, only the MET group demonstrated a significant augmentation in the MRCP (29.3%, P <0.001); the MRCP increase in CST group was at boarder-line significance level (12.11%, P = 0.061) and that for CTRL group was only 4.9% (P = 0.539). These results suggest that high mental effort training combined with low-intensity physical exercise is an effective method for voluntary muscle strengthening and this approach is especially beneficial for those who are physically weak and have difficulty undergoing conventional strength training. PMID:27310942

  12. Role of exercise intensity on GLUT4 content, aerobic fitness and fasting plasma glucose in type 2 diabetic mice.

    PubMed

    Cunha, Verusca Najara; de Paula Lima, Mérica; Motta-Santos, Daisy; Pesquero, Jorge Luiz; de Andrade, Rosangela Vieira; de Almeida, Jeeser Alves; Araujo, Ronaldo Carvalho; Grubert Campbell, Carmen Silvia; Lewis, John E; Simões, Herbert Gustavo

    2015-10-01

    Type 2 diabetes mellitus (T2D) results in several metabolic and cardiovascular dysfunctions, clinically characterized by hyperglycaemia due to lower glucose uptake and oxidation. Physical exercise is an effective intervention for glycaemic control. However, the effects of exercising at different intensities have not yet been addressed. The present study analysed the effects of 8 weeks of training performed at different exercise intensities on type 4 glucose transporters (GLUT4) content and glycaemic control of T2D (ob/ob) and non-diabetic mice (ob/OB). The animals were divided into six groups, with four groups being subjected either to low-intensity (ob/obL and ob/OBL: 3% body weight, three times/week/40 min) or high-intensity (ob/obH and ob/OBH: 6% body weight, three times per week per 20 min) swimming training. An incremental swimming test was performed to measure aerobic fitness. After the training intervention period, glycaemia and the content of GLUT4 were quantified. Although both training intensities were beneficial, the high-intensity regimen induced a more significant improvement in GLUT4 levels and glycaemic profile compared with sedentary controls (p < 0.05). Only animals in the high-intensity exercise group improved aerobic fitness. Thus, our study shows that high-intensity training was more effective for increasing GLUT4 content and glycaemia reduction in insulin-resistant mice, perhaps because of a higher metabolic demand imposed by this form of exercise.

  13. Versatility of `hemorheologic fitness' according to exercise intensity: emphasis on the "healthy primitive lifestyle"

    NASA Astrophysics Data System (ADS)

    Brun, Jean-Frédéric; Varlet-Marie, Emmanuelle; Chevance, Guillaume; Pollatz, Marion; Fedou, Christine; de Mauverger, Eric Raynaud

    2014-05-01

    We recently proposed a unifying hypothesis to reconcile unexpected findings in exercise hemorheology and the classical concepts of "hemorheologic fitness" and the "triphasic effects of exercise", based on the "healthy primitive lifestyle" paradigm. This paradigm assumes that evolution has selected genetic polymorphisms leading to insulin resistance as an adaptative strategy to cope with continuous low intensity physical activity and a special alimentation moderately high in protein, rich in low glycemic index carbohydrates, and poor in saturated fat. According to this protocol the true physiological picture would be that of an individual whose exercise and nutritional habits are close from this lifestyle, both sedentary subjects and trained athletes representing situations on the edge of this model. Unfortunately samples of people truly adhering to this ancestral lifestyle are hard to obtain. In order to address this picture we tried to compare databases obtained with our preceding published studies. As a model of the "healthy primitive lifestyle" we selected patients trained at low intensity (LI) and given an advice of protein intake around 1.2 g/kg/day. Results show a continuum for plasma viscosity which seems to be lower in athletes than LI-trained and even more sedentaries. When sedentary subjects become obese the most obvious characteristic is an increase in red blood cell (RBC) aggregation correlated to the size of fat stores. It is clear that 3 months of LI are not a perfect model of "healthy primitive lifestyle", but these data suggest that the most important effect of LI regular exercise is to decrease plasma viscosity and that sedentarity increases RBC aggregation mostly when it results in increased fat storage.

  14. Improve the Absolute Accuracy of Ozone Intensities in the 9-11 μm Region via Mw/ir Multi-Wavelength Spectroscopy

    NASA Astrophysics Data System (ADS)

    Yu, Shanshan; Drouin, Brian

    2016-06-01

    Ozone (O_3) is crucial for studies of air quality, human and crop health, and radiative forcing. Spectroscopic remote sensing techniques have been extensively employed to investigate ozone globally and regionally. Infrared intensities of ≤1% accuracy are desired by the remote sensing community. The accuracy of the current state-of-the-art infrared ozone intensities is on the order of 4-10%, resulting in ad hoc intensity scaling factors for consistent atmospheric retrievals. The large uncertainties on the infrared ozone intensities arise from the fact that pure ozone is very difficult to generate and sustain in the laboratory. Best estimates have employed IR/UV cross beam experiments to determine the accurate O_3 volume mixing ratio of the sample through its standard cross section value at 254 nm. This presentation reports our effort to improve the absolute accuracy of ozone intensities in the 9-11 μm region via a transfer of the precision of the rotational dipole moment onto the infrared measurement (MW/IR). Our approach was to use MW/IR cross beam experiments and determine the O_3 mixing ratio through alternately measuring pure rotation ozone lines from 692 to 779 GHz. The uncertainty of these pure rotation line intensities is better than 0.1%. The sample cell was a slow flow cross cell and the total pressure inside the sample cell was maintained constant through a proportional-integral-derivative (PID) flow control. Five infrared O_3 spectra were obtained, with a path length of 3.74 m, pressures ranging from 30 to 120 mTorr, and mixing ratio ranging from 0.5 to 0.9. A multi spectrum fitting technique was employed to fit all the FTS spectra simultaneously. The results show that we can determine intensities of the 9.6μm band with absolute accuracy better than 4%.

  15. 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.

  16. Much potential but many unanswered questions for high-intensity intermittent exercise training for patients with heart failure.

    PubMed

    Pinkstaff, Sherry O

    2015-01-01

    There is a robust trove of scientific studies that support the positive physical and mental health benefits associated with aerobic exercise for healthy individuals. These recommendations suggest that more vigorous exercise can be performed on fewer days for the same benefit. High-intensity intermittent exercise (HIIE) training has begun to show promise. HIIE seems safe and improves physiology, quality of life, and functional capacity. This review defines HIIE, discusses its physiologic benefit for patients with heart failure, outlines the studies that have been conducted to date, and places it in the context of the current clinical environment of exercise training for these patients.

  17. Comparison of the effect of different intensity exercise on a bicycle ergometer on postprandial lipidemia in type II diabetic patients

    PubMed Central

    Argani, Narges; Sharifi, Gholamreza; Golshahi, Jafar

    2014-01-01

    BACKGROUND Postprandial lipid clearance failure and lipoprotein disorders, which are independent risk factors for cardiovascular diseases are well-recognized in type II diabetes. Reduction of fats through exercise has been proved, though the mechanism is not well-defined, and the effects of different intensity exercise on postprandial lipidemia in diabetes type II is unknown. This study aims to find these effects using a cycle ergometer. METHODS On three different days, 15 type II diabetics (10 women and 5 men, with a mean age 42.07 ± 6.05 years, weight 94.64 ± 4.37 kg, height 159.78 ± 9.09 cm, and body mass index29.83 ± 3.93 kg/m2), consumed a full fat breakfast (750-800 kcal, 85% fat), and 150 min later, blood samples were taken from them to measure their lipid profile. The 1st day was the control day, without any exercises. Seven days later, 90 min after enriched breakfast, they did 30 min of exercise on the cycle ergometer with intensity of 55-70% of maximum heart rate (HRmax), and 14 days later, 90 min after enriched breakfast, they did 30 min of exercise with intensity of 70-85% of HRmax. RESULTS According to Friedman non-parametric test, high-density lipoprotein (HDL) cholesterol serum level significantly increased after 30 min of moderate intensity exercise (P > 0.05, from 39.4 ± 5.2 to 48.6 ± 9.3), while this increase was insignificant after a higher intensity exercise. Neither intensity levels had any significant effects on triglyceride or on low-density lipoprotein cholesterol. CONCLUSION Results showed that moderate intensity exercise was more effective in increasing HDL cholesterol level in type II diabetics. PMID:25161685

  18. Reduction in mdx mouse muscle degeneration by low-intensity endurance exercise: a proteomic analysis in quadriceps muscle of exercised compared with sedentary mdx mice

    PubMed Central

    Fontana, Simona; Schillaci, Odessa; Frinchi, Monica; Giallombardo, Marco; Morici, Giuseppe; Liberto, Valentina Di; Alessandro, Riccardo; De Leo, Giacomo; Perciavalle, Vincenzo; Belluardo, Natale; Mudò, Giuseppa

    2015-01-01

    In our recent study was shown a significant recovery of damaged skeletal muscle of mice with X-linked muscular dystrophy (mdx) following low-intensity endurance exercise, probably by reducing the degeneration of dystrophic muscle. Consequently, in the present work, we aimed to identify proteins involved in the observed reduction in degenerating fibres. To this end, we used proteomic analysis to evaluate changes in the protein profile of quadriceps dystrophic muscles of exercised compared with sedentary mdx mice. Four protein spots were found to be significantly changed and were identified as three isoforms of carbonic anhydrase 3 (CA3) and superoxide dismutase [Cu-Zn] (SODC). Protein levels of CA3 isoforms were significantly up-regulated in quadriceps of sedentary mdx mice and were completely restored to wild–type (WT) mice values, both sedentary and exercised, in quadriceps of exercised mdx mice. Protein levels of SODC were down-regulated in quadriceps of sedentary mdx mice and were significantly restored to WT mice values, both sedentary and exercised, in quadriceps of exercised mdx mice. Western blot data were in agreement with those obtained using proteomic analysis and revealed the presence of one more CA3 isoform that was significantly changed. Based on data found in the present study, it seems that low-intensity endurance exercise may in part contribute to reduce cell degeneration process in mdx muscles, by counteracting oxidative stress. PMID:26182375

  19. Reduction in mdx mouse muscle degeneration by low-intensity endurance exercise: a proteomic analysis in quadriceps muscle of exercised compared with sedentary mdx mice.

    PubMed

    Fontana, Simona; Schillaci, Odessa; Frinchi, Monica; Giallombardo, Marco; Morici, Giuseppe; Di Liberto, Valentina; Alessandro, Riccardo; De Leo, Giacomo; Perciavalle, Vincenzo; Belluardo, Natale; Mudò, Giuseppa

    2015-01-01

    In our recent study was shown a significant recovery of damaged skeletal muscle of mice with X-linked muscular dystrophy (mdx) following low-intensity endurance exercise, probably by reducing the degeneration of dystrophic muscle. Consequently, in the present work, we aimed to identify proteins involved in the observed reduction in degenerating fibres. To this end, we used proteomic analysis to evaluate changes in the protein profile of quadriceps dystrophic muscles of exercised compared with sedentary mdx mice. Four protein spots were found to be significantly changed and were identified as three isoforms of carbonic anhydrase 3 (CA3) and superoxide dismutase [Cu-Zn] (SODC). Protein levels of CA3 isoforms were significantly up-regulated in quadriceps of sedentary mdx mice and were completely restored to wild-type (WT) mice values, both sedentary and exercised, in quadriceps of exercised mdx mice. Protein levels of SODC were down-regulated in quadriceps of sedentary mdx mice and were significantly restored to WT mice values, both sedentary and exercised, in quadriceps of exercised mdx mice. Western blot data were in agreement with those obtained using proteomic analysis and revealed the presence of one more CA3 isoform that was significantly changed. Based on data found in the present study, it seems that low-intensity endurance exercise may in part contribute to reduce cell degeneration process in mdx muscles, by counteracting oxidative stress. PMID:26182375

  20. Acetazolamide attenuates transvascular fluid flux in equine lungs during intense exercise.

    PubMed

    Vengust, Modest; Staempfli, Henry; Viel, Laurent; Swenson, Erik R; Heigenhauser, George

    2013-09-15

      During intense exercise in horses the transvascular fluid flux in the pulmonary circulation (Jv-a) represents 4% of cardiac output (Q). This fluid flux has been attributed to an increase in pulmonary transmural hydrostatic forces, increases in perfused microvascular surface area, and reversible alterations in capillary permeability under conditions of high flow and pressure. Erythrocyte fluid efflux, however, accounts for a significant fraction of Jv-a. In the lung the Jacobs-Stewart cycle occurs with diffusion of CO2 into alveolar space with possible accompanying chloride (Cl-) and water movement from the erythrocyte directly into the pulmonary interstitium. We hypothesised that inhibition of carbonic anhydrase in erythrocytes inhibits the Jacobs-Stewart cycle and attenuates Jv-a. Five horses were exercised on a treadmill until fatigue without (control) and with acetazolamide treatment (30 mg kg(-1) 30 min before exercise). Erythrocyte fluid efflux, plasma fluid flux across the lung and Jv-a were calculated using haemoglobin, haematocrit, plasma protein and Q. Fluid fluxes were used to calculate erythrocyte, plasma and whole blood Cl- fluxes across the lung. Cardiac output was not different between control and acetazolamide treatment. During exercise erythrocyte fluid efflux and Jv-a increased in control (9.3±3.3 and 11.0±4.4 l min(-1), respectively) and was higher than after acetazolamide treatment (3.8±1.6 and 1.2±1.2 l min(-1), respectively) (P<0.05). Plasma fluid flux did not change from rest in control and decreased after acetazolamide treatment (-4.5±1.5 l min(-1)) (P<0.05). Erythrocyte Cl- flux increased during exercise in control and after acetazolamide treatment (P<0.05). During exercise plasma Cl- flux across the lung did not change in control; however, it increased with acetazolamide treatment (P=0.0001). During exercise whole blood Cl- flux increased across the lung in control (P<0.05) but not after acetazolamide treatment. The results

  1. Comparison of memory and combined exercise and memory-anchoring procedures on ratings of perceived exertion during short duration, near-peak-intensity cycle ergometer exercise.

    PubMed

    Gearhart, Randall F; Becque, M Daniel; Hutchins, Matthew D; Palm, Chad M

    2004-12-01

    The purpose of this study was to compare ratings of perceived exertion (RPE) following memory-anchoring and two different types of combined exercise and memory-anchoring during short duration, near-peak-intensity cycle exercise. Thirty recreationally trained males volunteered to participate. The M group, n = 10, received only verbal instructions prior to the experimental trial. The EM1 group, n = 10, and the EM2 group, n = 10, received the same verbal instructions, but these were administered while participants performed maximal, graded cycle ergometer exercise. The low perceptual anchor was established during light pedaling for both EM1 and EM2. The high perceptual anchor was established during the final stage of the maximal cycle test for EM1 and during a 30-sec. sprint immediately following the final stage of the maximal cycle ergometer testing for EM2. On the experimental trial pedaling at maximal intensity for 30-sec. was against a resistance equal to .10 x body mass (kg) on a cycle ergometer. The Borg 15-category RPE scale was used to record exertional perceptions. RPE was reported at 8, 13, 18, 23, and 28 sec. each trial. Ratings were similar among the three groups. Their linear regression slopes and intercepts were also similar. Memory-anchoring produced similar RPE for two different combined exercise and memory-anchoring procedures. In conclusion, memory-anchoring and combined exercise and memory-anchoring produce similar RPE during high intensity, short duration cycle exercise in young recreationally trained athletes.

  2. Changes in technique and efficiency after high-intensity exercise in cross-country skiers.

    PubMed

    Åsan Grasaas, Christina; Ettema, Gertjan; Hegge, Ann Magdalen; Skovereng, Knut; Sandbakk, Øyvind

    2014-01-01

    This study investigated changes in technique and efficiency after high-intensity exercise to exhaustion in elite cross-country skiers. Twelve elite male skiers completed 4 min submaximal exercise before and after a high-intensity incremental test to exhaustion with the G3 skating technique on a 5% inclined roller-ski treadmill. Kinematics and kinetics were monitored by instrumented roller skis, work rate was calculated as power against roller friction and gravity, aerobic metabolic cost was determined from gas exchange, and blood lactate values indicated the anaerobic contribution. Gross efficiency was the work rate divided by aerobic metabolic rate. A recovery period of 10 min between the incremental test and the posttest was included to allow the metabolic values to return to baseline. Changes in neuromuscular fatigue in upper and lower limbs before and after the incremental test were indicated by peak power in concentric bench press and squat-jump height. From pretest to posttest, cycle length decreased and cycle rate increased by approximately 5% (P < 0.001), whereas the amount of ski forces did not change significantly. Oxygen uptake increased by 4%, and gross efficiency decreased from 15.5% ± 0.7% to 15.2% ± 0.5% from pretest to posttest (both P < .02). Correspondingly, blood lactate concentration increased from 2.4 ± 1.0 to 6.2 ± 2.5 mmol/L (P < .001). Bench-press and squat-jump performance remained unaltered. Elite cross-country skiers demonstrated a less efficient technique and shorter cycle length during submaximal roller-ski skating after high-intensity exercise. However, there were no changes in ski forces or peak power in the upper and lower limbs that could explain these differences.

  3. Low-intensity isometric handgrip exercise has no transient effect on blood pressure in patients with coronary artery disease.

    PubMed

    Goessler, Karla; Buys, Roselien; Cornelissen, Véronique A

    2016-08-01

    Hypertension is highly prevalent among patients with coronary artery disease (CAD). Exercise-based cardiac rehabilitation reduces blood pressure (BP). However, less is known about the transient effect of a single bout of exercise on BP. Isometric handgrip exercise has been proposed as a new nonpharmacologic tool to lower BP. We aimed to investigate the acute effect of isometric handgrip exercise on BP in CAD patients. Twenty-one male CAD patients were included. All patients completed two experimental sessions in random order: one control and one low-intensity isometric handgrip session. BP was measured by means of a 24-hour ambulatory BP monitor preintervention, for 1 hour in the office and subsequently for 24 hours. Our results suggest that isometric handgrip exercise performed at low intensity is safe in patients with CAD but does not induce a transient reduction in BP.

  4. Acute high-intensity exercise-induced cognitive enhancement and brain-derived neurotrophic factor in young, healthy adults.

    PubMed

    Hwang, Jungyun; Brothers, R Matthew; Castelli, Darla M; Glowacki, Elizabeth M; Chen, Yen T; Salinas, Mandy M; Kim, Jihoon; Jung, Yeonhak; Calvert, Hannah G

    2016-09-01

    Acute exercise can positively impact cognition. The present study examined the effect of acute high-intensity aerobic exercise on prefrontal-dependent cognitive performance and brain-derived neurotrophic factor (BDNF). Fifty-eight young adults were randomly assigned to one of two experimental groups: (a) an acute bout of high-intensity exercise (n=29) or (b) a non-exercise control (n=29). Participants in the exercise group improved performance on inhibitory control in Stroop interference and on cognitive flexibility in Trail Making Test (TMT) Part-B compared with participants in the control group and increased BDNF immediately after exercise. There was a significant relationship between BDNF and TMT Part-B on the pre-post change following exercise. These findings provide support for the association between improved prefrontal-dependent cognitive performance and increased BDNF in response to acute exercise. We conclude that the changes in BDNF concentration may be partially responsible for prefrontal-dependent cognitive functioning following an acute bout of exercise. PMID:27450438

  5. Acute high-intensity exercise-induced cognitive enhancement and brain-derived neurotrophic factor in young, healthy adults.

    PubMed

    Hwang, Jungyun; Brothers, R Matthew; Castelli, Darla M; Glowacki, Elizabeth M; Chen, Yen T; Salinas, Mandy M; Kim, Jihoon; Jung, Yeonhak; Calvert, Hannah G

    2016-09-01

    Acute exercise can positively impact cognition. The present study examined the effect of acute high-intensity aerobic exercise on prefrontal-dependent cognitive performance and brain-derived neurotrophic factor (BDNF). Fifty-eight young adults were randomly assigned to one of two experimental groups: (a) an acute bout of high-intensity exercise (n=29) or (b) a non-exercise control (n=29). Participants in the exercise group improved performance on inhibitory control in Stroop interference and on cognitive flexibility in Trail Making Test (TMT) Part-B compared with participants in the control group and increased BDNF immediately after exercise. There was a significant relationship between BDNF and TMT Part-B on the pre-post change following exercise. These findings provide support for the association between improved prefrontal-dependent cognitive performance and increased BDNF in response to acute exercise. We conclude that the changes in BDNF concentration may be partially responsible for prefrontal-dependent cognitive functioning following an acute bout of exercise.

  6. [Rhabdomyolysis in a well-trained woman after unusually intense exercise].

    PubMed

    Larsen, Christian; Jensen, Mogens Pfeiffer

    2014-06-16

    A 35-year-old woman was acutely hospitalized with oedema of the upper limbs, reduced force, severe movement reduction and muscle pain in both upper extremities. Her symptoms started after three days of intense exercise doing kayaking and a lot of pull-ups in crossfit. Rhabdomyolysis is a syndrome, characterized by muscle necrosis. Usually there is a marked elevation of creatine kinase (CK) concentration with symptoms as described and myoglobinuria (dark coloured urine). After hard muscular work there will often be asymptomatic, but significant elevations in CK concentration, and in rare cases life-threatening rhabdomyolysis with electrolyte imbalances and acute kidney failure.

  7. Hatha Yoga Practices: Energy Expenditure, Respiratory Changes and Intensity of Exercise

    PubMed Central

    Ray, Uday Sankar; Pathak, Anjana; Tomer, Omveer Singh

    2011-01-01

    The aim of this study was to critically observe the energy expenditure, exercise intensity and respiratory changes during a full yoga practice session. Oxygen consumption (V˙O2), carbon dioxide output (V˙CO2), pulmonary ventilation (V˙E), respiratory rate (Fr) and tidal volume (VT), were measured in 16 physical posture (asanas), five yoga breathing maneuvers (BM) and two types of meditation. Twenty male (age 27.3 ± 3.5 years, height 166.6 ± 5.4 cm and body weight 58.8 ± 9.6 kg) yoga instructors were studied. Their maximal oxygen consumption (V˙O2max) was recorded. The exercise intensity in asanas was expressed in percentage V˙O2max . In asanas, exercise intensity varied from 9.9 to 26.5% of V˙O2max . Highest energy cost was 3.02 kcal min−1. In BM highest V˙E was 53.7 ± 15.5 l min−1. VT was 0.97 ± 0.59, 1.41 ± 1.27 and 1.28 ± l/breath with corresponding Fr of 14.0 ± 5.3, 10.0 ± 6.35, 10.0 ± 5.8 breaths/min. Average energy expenditure in asanas, BM and meditation were 2.29, 1.91 and 1.37 kcal min−1, respectively. Metabolic rate was generally in the range of 1-2 metabolic equivalents (MET) except in three asanas where it was >2 MET. V˙O2 was 0.27 ± 0.05 and 0.24 ± 0.04 l min−1 in meditation and Shavasana, respectively. Although yogic practices are low intensity exercises within lactate threshold, physical performance improvement is possible owing to both better economy of breathing by BM and also by improvement in cardiovascular reserve. Other factors such as psycho-physiological and better relaxation may contribute to it. PMID:21799675

  8. [Rhabdomyolysis in a well-trained woman after unusually intense exercise].

    PubMed

    Larsen, Christian; Jensen, Mogens Pfeiffer

    2014-06-16

    A 35-year-old woman was acutely hospitalized with oedema of the upper limbs, reduced force, severe movement reduction and muscle pain in both upper extremities. Her symptoms started after three days of intense exercise doing kayaking and a lot of pull-ups in crossfit. Rhabdomyolysis is a syndrome, characterized by muscle necrosis. Usually there is a marked elevation of creatine kinase (CK) concentration with symptoms as described and myoglobinuria (dark coloured urine). After hard muscular work there will often be asymptomatic, but significant elevations in CK concentration, and in rare cases life-threatening rhabdomyolysis with electrolyte imbalances and acute kidney failure. PMID:25352283

  9. Crystalline sulfur dioxide: Crystal field splittings, absolute band intensities and complex refractive indices derived from infrared spectra

    NASA Technical Reports Server (NTRS)

    Khanna, R. K.; Zhao, Guizhi

    1986-01-01

    The infrared absorption spectra of thin crystalline films of sulfur dioxide at 90 K are reported in the 2700 to 450/cm region. The observed multiplicity of the spectral features in the regions of fundamentals is attributed to factor group splittings of the modes in a biaxial crystal lattice and the naturally present minor S-34, S-36, and O-18 isotopic species. Complex refractive indices determined by an iterative Kramers-Kronig analysis of the extinction data, and absolute band strengths derived from them, are also reported in this region.

  10. Increased mortality in patients with severe COPD associated with high-intensity exercise: a preliminary cohort study

    PubMed Central

    Schaadt, Lone; Christensen, Robin; Kristensen, Lars Erik; Henriksen, Marius

    2016-01-01

    Introduction Intensity of exercise is believed to be a key determinant of response to chronic obstructive pulmonary disease (COPD) rehabilitation. We hypothesized that a higher intensity of exercise, in combination with physiotherapist-led instructions and education in management of breathlessness, would lead to better self-management, possibly delaying calls to the emergency service and preventing hospitalization. Objective We aimed to test this hypothesis in a subsequent randomized trial, and in order to test study processes and estimate hospitalization rates, we did a small preliminary prospective cohort study on severe COPD patients referred to outpatient rehabilitation. Methods In 2013, four rehabilitation courses were scheduled (spring, summer, autumn, and winter) each lasting 8 weeks and including eight to ten patients. This preliminary study was designed as a controlled cohort study. The bi-weekly exercise sessions in the spring and autumn courses included a high-intensity walking exercise at 95% of estimated VO2 max for as long as possible. The other two rehabilitation courses included the usual walking exercise intensity (85% of estimated VO2 max). Hospitalization rates were assessed from the participants’ medical records in an 18-month period. Results We were able to enroll 31 patients in total (15 in the high-intensity exercise group and 16 in regular intensity). There were no group differences in the hospitalization rates. However, during review of the medical records, we observed a striking mortality rate among participants who had attended the high-intensity rehabilitation courses (five deaths) compared to the standard rehabilitation (zero deaths). Four of the five deaths were COPD exacerbations. Fisher’s exact test was statistically significant (P=0.046), as was a log-rank test (P=0.019) of the Kaplan–Meier estimated survival rates. Conclusion These results from this small preliminary cohort study are alarming and raise concerns about the

  11. 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

  12. Continuous Exercise but Not High Intensity Interval Training Improves Fat Distribution in Overweight Adults

    PubMed Central

    Keating, Shelley E.; Machan, Elizabeth A.; O'Connor, Helen T.; Gerofi, James A.; Sainsbury, Amanda; Caterson, Ian D.; Johnson, Nathan A.

    2014-01-01

    Objective. The purpose of this study was to assess the effect of high intensity interval training (HIIT) versus continuous aerobic exercise training (CONT) or placebo (PLA) on body composition by randomized controlled design. Methods. Work capacity and body composition (dual-energy X-ray absorptiometry) were measured before and after 12 weeks of intervention in 38 previously inactive overweight adults. Results. There was a significant group × time interaction for change in work capacity (P < 0.001), which increased significantly in CONT (23.8 ± 3.0%) and HIIT (22.3 ± 3.5%) but not PLA (3.1 ± 5.0%). There was a near-significant main effect for percentage trunk fat, with trunk fat reducing in CONT by 3.1 ± 1.6% and in PLA by 1.1 ± 0.4%, but not in HIIT (increase of 0.7 ± 1.0%) (P = 0.07). There was a significant reduction in android fat percentage in CONT (2.7 ± 1.3%) and PLA (1.4 ± 0.8%) but not HIIT (increase of 0.8 ± 0.7%) (P = 0.04). Conclusion. These data suggest that HIIT may be advocated as a time-efficient strategy for eliciting comparable fitness benefits to traditional continuous exercise in inactive, overweight adults. However, in this population HIIT does not confer the same benefit to body fat levels as continuous exercise training. PMID:24669314

  13. Effect of Exercise Intensity on Spontaneous Physical Activity Energy Expenditure in Overweight Boys: A Crossover Study

    PubMed Central

    Paravidino, Vitor Barreto; Mediano, Mauro Felippe Felix; Hoffman, Daniel J.; Sichieri, Rosely

    2016-01-01

    Objective Evaluate the effect of different exercise intensities on spontaneous physical activity energy expenditure in overweight adolescents. Methods A crossover study was developed with a control session, followed by moderate and vigorous exercise sessions, with six days of monitoring each. Twenty-four adolescents, 11–13 years old, male and overweight were selected. Spontaneous physical activity energy expenditure was assessed by accelerometers. Linear mixed effects models were used to evaluate the differences per session across time. Results Energy expenditure during the 1st hour was different between all three sessions, with averages of 82, 286 and 343 kcal to the control, moderate and vigorous sessions, respectively (p <0.001). The same pattern of difference in energy expenditure between the sessions remained after 24 hours (704 vs 970 vs 1056 kcal, p <0.001). However, energy expenditure during the six days indicates compensation from second to the sixth day, although small differences remained at the end of the 6-day period (5102 vs 5193 vs 5271 kcal, p <0.001). Conclusions A single aerobic session seems to modify the spontaneous physical activities in overweight adolescents but still keeping the vigorous session with higher total energy expenditure during the follow-up period. Despite the observed compensatory effect, the greater energy expenditure observed in both moderate and vigorous exercise sessions indicates that physical activity should be recommended to promote an increased energy expenditure in adolescents. Trial Registration ClinicalTrials.gov NCT 02272088 PMID:26771742

  14. Effects of High-Intensity Blood Flow Restriction Exercise on Muscle Fatigue

    PubMed Central

    Neto, Gabriel R.; Santos, Heleodório H.; Sousa, Juliana B. C.; Júnior, Adenilson T. A.; Araújo, Joamira P.; Aniceto, Rodrigo R.; Sousa, Maria S. C.

    2014-01-01

    Strength training combined with blood flow restriction (BFR) have been used to improve the levels of muscle adaptation. The aim of this paper was to investigate the acute effect of high intensity squats with and without blood flow restriction on muscular fatigue levels. Twelve athletes (aged 25.95 ± 0.84 years) were randomized into two groups: without Blood Flow Restriction (NFR, n = 6) and With Blood Flow Restriction (WFR, n = 6) that performed a series of free weight squats with 80% 1-RM until concentric failure. The strength of the quadriceps extensors was assessed in a maximum voluntary isometric contraction integrated to signals from the surface electromyogram. The average frequency showed significant reductions in the WFR group for the vastus lateralis and vastus medialis muscles, and intergroup only for the vastus medialis. In conclusion, a set of squats at high intensity with BFR could compromise muscle strength immediately after exercise, however, differences were not significant between groups. PMID:25114743

  15. The physiology of soccer--with special reference to intense intermittent exercise.

    PubMed

    Bangsbo, J

    1994-01-01

    The present thesis is based on 14 original articles published in international journals (I-XIV, see page 8) and a summarizing review. The thesis deals with the physiological demands of soccer, with a particular focus on the physiological response to repeated intense exercise. In chapter I the specific issues are presented and in chapter II the physiological demands in soccer are discussed based on the results of the studies performed. Chapter III contains a short survey of the experiments performed to study specifically muscle metabolism and muscle fatigue with repeated intense muscle contractions. With reference to the topics covered in chapters II and III, fatigue during a soccer match is discussed in chapter IV, and chapter V deals with applications for physical training in soccer. Measurements have been performed during soccer matches and training, as well as in experiments simulating the activities of a soccer match. The information obtained has been compared to results from studies of the physical capacity of top-class soccer players and from laboratory experiments aimed at investigating metabolism and fatigue in intermittent exercise. Studies with whole-body and single muscle group exercises have been performed, the latter mainly with the application of a knee-extension model. In the studies on isolated muscle groups, biopsies taken from exercising muscles as well as arterial and femoral venous blood samples have allowed for detailed analysis of muscle ionic transportation and metabolism. In addition, the magnetic resonance technique has been used for the continuous determination of changes in muscle metabolites and pH during intermittent exercise. Analysis of activities during soccer matches showed that a top-class soccer player covers an average distance of approximately 11 km during a match. The distance differs highly between players and is partly related to the position in a team. Midfield players run more at low speed than defenders and forwards

  16. Fat oxidation over a range of exercise intensities: fitness versus fatness.

    PubMed

    Croci, Ilaria; Hickman, Ingrid J; Wood, Rachel E; Borrani, Fabio; Macdonald, Graeme A; Byrne, Nuala M

    2014-12-01

    Maximal fat oxidation (MFO), as well as the exercise intensity at which it occurs (Fatmax), have been reported as lower in sedentary overweight individuals but have not been studied in trained overweight individuals. The aim of this study was to compare Fatmax and MFO in lean and overweight recreationally trained males matched for cardiorespiratory fitness (CRF) and to study the relationships between these variables, anthropometric characteristics, and CRF. Twelve recreationally trained overweight (high fatness (HiFat) group, 30.0% ± 5.3% body fat) and 12 lean males (low fatness (LoFat), 17.2% ± 5.7% body fat) matched for CRF (maximal oxygen consumption (V̇O2max) 39.0 ± 5.5 vs. 41.4 ± 7.6 mL·kg(-1)·min(-1), p = 0.31) and age (p = 0.93) performed a graded exercise test on a cycle ergometer. V̇O2max and fat and carbohydrate oxidation rates were determined using indirect calorimetry; Fatmax and MFO were determined with a mathematical model (SIN); and % body fat was assessed by air displacement plethysmography. MFO (0.38 ± 0.19 vs. 0.42 ± 0.16 g·min(-1), p = 0.58), Fatmax (46.7% ± 8.6% vs. 45.4% ± 7.2% V̇O2max, p = 0.71), and fat oxidation rates over a wide range of exercise intensities were not significantly different (p > 0.05) between HiFat and LoFat groups. In the overall cohort (n = 24), MFO and Fatmax were correlated with V̇O2max (r = 0.46, p = 0.02; r = 0.61, p = 0.002) but not with % body fat or body mass index (p > 0.05). Fat oxidation during exercise was similar in recreationally trained overweight and lean males matched for CRF. Consistently, substrate oxidation rates during exercise were not related to adiposity (% body fat) but were related to CRF. The benefits of high CRF independent of body weight and % body fat should be further highlighted in the management of obesity.

  17. Exercises

    MedlinePlus

    ... Obstructive Pulmonary Disease (COPD) COPD: Lifestyle Management Exercises Exercises Make an Appointment Refer a Patient Ask a ... riding a stationary bike. Medication to Help You Exercise People with COPD often use a metered-dose ...

  18. Increasing Exercise Intensity Reduces Heterogeneity of Glucose Uptake in Human Skeletal Muscles

    PubMed Central

    Kemppainen, Jukka; Fujimoto, Toshihiko; Knuuti, Juhani; Kalliokoski, Kari K.

    2012-01-01

    Proper muscle activation is a key feature of survival in different tasks in daily life as well as sports performance, but can be impaired in elderly and in diseases. Therefore it is also clinically important to better understand the phenomenon that can be elucidated in humans non-invasively by positron emission tomography (PET) with measurements of spatial heterogeneity of glucose uptake within and among muscles during exercise. We studied six healthy young men during 35 minutes of cycling at relative intensities of 30% (low), 55% (moderate), and 75% (high) of maximal oxygen consumption on three separate days. Glucose uptake in the quadriceps femoris muscle group (QF), the main force producing muscle group in recreational cycling, and its four individual muscles, was directly measured using PET and 18F-fluoro-deoxy-glucose. Within-muscle heterogeneity was determined by calculating the coefficient of variance (CV) of glucose uptake in PET image voxels within the muscle of interest, and among-muscles heterogeneity of glucose uptake in QF was expressed as CV of the mean glucose uptake values of its separate muscles. With increasing intensity, within-muscle heterogeneity decreased in the entire QF as well as within its all four individual parts. Among-muscles glucose uptake heterogeneity also decreased with increasing intensity. However, mean glucose uptake was consistently lower and heterogeneity higher in rectus femoris muscle that is known to consist of the highest percentage of fast twitch type II fibers, compared to the other three QF muscles. In conclusion, these results show that in addition to increased contribution of distinct muscle parts, with increases in exercise intensity there is also an enhanced recruitment of muscle fibers within all of the four heads of QF, despite established differences in muscle-part specific fiber type distributions. Glucose uptake heterogeneity may serve as a useful non-invasive tool to elucidate muscle activation in aging and

  19. Short-Wave Diathermy Pretreatment and Inflammatory Myokine Response After High-Intensity Eccentric Exercise

    PubMed Central

    Vardiman, John P.; Moodie, Nicole; Siedlik, Jacob A.; Kudrna, Rebecca A.; Graham, Zachary; Gallagher, Philip

    2015-01-01

    Context Various modalities have been used to pretreat skeletal muscle to attenuate inflammation. Objective To determine the effects of short-wave diathermy (SWD) preheating treatment on inflammation and stress markers after eccentric exercise. Design Controlled laboratory study. Setting University laboratory setting. Patients or Other Participants Fifteen male (age = 22 ± 4.9 years, height = 179.75 ± 9.56 cm, mass = 82.22 ± 12.67 kg) college-aged students. Intervention(s) Seven participants were selected randomly to receive 40 minutes of SWD heat treatment (HT), and 8 participants served as the control (CON) group and rested without SWD. Both groups completed 7 sets of 10 repetitions of a high-intensity eccentric exercise protocol (EEP) at 120% of the 1-repetition maximum (1-RM) leg extension. Main Outcome Measure(s) We biopsied muscles on days 1, 3 (24 hours post-EEP), and 4 (48 hours post-EEP) and collected blood samples on days 1, 2 (4 hours post-EEP), 3, and 4. We determined 1-RM on day 2 (24 hours post-SWD) and measured 1-RM on days 3 and 4. We analyzed the muscle samples for interleukin 6 (IL-6), tumor necrosis factor α, and heat shock protein 70 and the blood for serum creatine kinase. Results We found a group × time interaction for intramuscular IL-6 levels after SWD (F2,26 = 7.13, P = .003). The IL-6 decreased in HT (F1,6 = 17.8, P = .006), whereas CON showed no change (P > .05). We found a group × time interaction for tumor necrosis factor α levels (F2,26 = 3.71, P = .04), which increased in CON (F2,14 = 7.16, P = .007), but saw no changes for HT (P > .05). No group × time interactions were noted for 1-RM, heat shock protein 70, or creatine kinase (P > .05). Conclusions The SWD preheating treatment provided a treatment effect for intramuscular inflammatory myokines induced through high-intensity eccentric exercise but did not affect other factors associated with intense exercise and inflammation. PMID:25844857

  20. High-Intensity Intermittent Exercise and its Effects on Heart Rate Variability and Subsequent Strength Performance

    PubMed Central

    Panissa, Valéria L. G.; Cal Abad, Cesar C.; Julio, Ursula F.; Andreato, Leonardo V.; Franchini, Emerson

    2016-01-01

    Prupose: To investigate the effects of a 5-km high-intensity interval exercise (HIIE) on heart rate variability (HRV) and subsequent strength performance. Methods: Nine trained males performed a control session composed of a half-squat strength exercise (4 × 80% of one repetition maximum—1 RM) in isolation and 30-min, 1-, 4-, 8-, and 24-h after an HIIE (1-min at the velocity peak:1-min passive recovery). All experimental sessions were performed on different days. The maximum number of repetitions (MNR) and total weight lifted (TWL) during the strength exercise were registered in all conditions; in addition, prior to each session, HRV were assessed [beat-to-beat intervals (RR) and log-transformed of root means square of successive differences in the normal-to-normal intervals (lnRMSSD)]. Results: Performance in the strength exercise dropped at 30-min (31%) and 1-h (19%) post-HIIE concomitantly with lower values of RR (781 ± 79 ms; 799 ± 134 ms, respectively) in the same recovery intervals compared to the control (1015 ± 197 ms). Inferential analysis did not detect any effect of condition on lnRMSSD, however, values were lower after 30-min (3.5 ± 0.4 ms) and 1-h (3.3 ± 0.5 ms) with moderate and large effect sizes (0.9 and 1.2, respectively) compared with the control condition (3.9 ± 0.4 ms). Conclusion: Both RR and lnRMSSD seem to be associated with deleterious effects on strength performance, although further studies should be conducted to clarify this association. PMID:26973543

  1. Augmented baroreflex heart rate gain after moderate-intensity, dynamic exercise

    NASA Technical Reports Server (NTRS)

    Halliwill, J. R.; Taylor, J. A.; Hartwig, T. D.; Eckberg, D. L.

    1996-01-01

    The occurrence of a sustained vasodilation and hypotension after acute, dynamic exercise suggests that exercise may alter arterial baroreflex mechanisms. Therefore, we assessed systemic hemodynamics, baroreflex regulation of heart rate, and cardiac vagal tone after 60 min of cycling at 60% peak oxygen consumption in 12 healthy, untrained men and women (ages 21-28 yr). We derived sigmoidal carotid-cardiac baroreflex relations by measurement of R-R interval changes induced by ramped, stepwise, R-wave-triggered changes in external neck pressure from 40 to -65 mmHg. We estimated tonic cardiac vagal control with power spectral analysis of R-R interval variability in the respiratory frequency band (0.2-0.3 Hz) during frequency- and tidal volume-controlled breathing. Both mean arterial pressure and total peripheral resistance were reduced postexercise [pressure: from 86 +/- 2 (mean +/- SE) to 81 +/- 2 mmHg; resistance: from 23 +/- 2 to 16 +/- 1 units; both P < 0.05]. Cardiac output was increased postexercise (from 3.9 +/- 0.3 to 5.5 +/- 0.5 l/min, P < 0.05). Both slope and range of the carotid-cardiac baroreflex relation were increased postexercise (slope: from 4.7 +/- 0.7 to 6.1 +/- 0.9 ms/mmHg; range: from 186 +/- 23 to 238 +/- 30 ms, P < 0.05). Respiratory R-R interval variability (cardiac vagal tone) was not changed at any time after exercise, whereas heart rate and plasma norepinephrine levels were elevated. Thus moderate-intensity, dynamic exercise increases heart rate and cardiac output, reduces peripheral vascular resistance, and augments baroreflex responsiveness. Our data suggest that augmented baroreflex heart rate gain restrains rather than contributes to postexercise hypotension, which appears to be mediated predominately by vasodilation.

  2. Absolute intensities for the Q-branch of the 3 nu(sub 2) (-) nu(sub 1) (465.161/cm) band of nitrous oxide

    NASA Technical Reports Server (NTRS)

    Sirota, J. Marcos; Reuter, Dennis C.

    1993-01-01

    The absolute intensities of four lines, Q 15-Q 18 in the 03(sup 1)0-10(sup 0)0 band, of N2O have been measured using a tunable diode laser spectrometer at temperatures between 380 and 420 K and pressures between 4 and 15 torr. Even though these transitions are weak and produced only about 2% of absorption at the line center for a pathlength of 52 m, they were measured with a signal to noise ratio of about 20 due to the high sensitivity of the instrument. The band strength derived is 1.03 x 10(exp -24) cm/molec at 296 K.

  3. Plasma glutamine changes after high-intensity exercise in elite male swimmers.

    PubMed

    Kargotich, Stephen; Rowbottom, David G; Keast, David; Goodman, Carmél; Dawson, Brian; Morton, Alan R

    2005-01-01

    The aim of this study was to establish the pattern and time course of plasma glutamine recovery after acute, high-intensity exercise in well-trained swimmers. In Study 1, elite male swimmers (n=8) performed 15 x 100 m swimming intervals (ITS) at 70% and 95% of maximal 100m freestyle time. Resting plasma glutaminle levels were determined on a nonexercise control day (0% ITS). Venous blood samples were obtained prior to, immediately afte;, and 30, 60, 120, and 150 mini postexercise. In Study 2, the 95% ITS was repeated in elite male swuimmers (n=8), while control subjects (n=8) did not exercise, to test for any diurnal variation in plasma glutamine levels. Venous blood samples were obtained prior to and 2, 4, 6, and 8 h postexercise. In Study 1, no change was observed in plasma glutamine following the 0% (control) and 70% ITS, but following the 95% ITS glutamine decreased significantly (p < 0.01) over the recovery period. In Study 2, plasma glutamine again decreased over the recovery period in the swimmers, but no changes were observed in the controls. It was concluded that intensive swim traininlg results in postexercise decreases in plasma glutamine levels. Because glutamine has been suggested as a marker of overtraining, a need to measure glutaminle at standard times within training programs is indicated. PMID:16389883

  4. The Utility of a High-intensity Exercise Protocol to Prospectively Assess ACL Injury Risk.

    PubMed

    Bossuyt, F M; García-Pinillos, F; Raja Azidin, R M F; Vanrenterghem, J; Robinson, M A

    2016-02-01

    This study investigated the utility of a 5-min high-intensity exercise protocol (SAFT(5)) to include in prospective cohort studies investigating ACL injury risk. 15 active females were tested on 2 occasions during which their non-dominant leg was analysed before SAFT(5) (PRE), immediately after (POST0), 15 min after (POST15), and 30 min after (POST30). On the first occasion, testing included 5 maximum isokinetic contractions for eccentric and concentric hamstring and concentric quadriceps and on the second occasion, 3 trials of 2 landing tasks (i. e., single-leg hop and drop vertical jump) were conducted. Results showed a reduced eccentric hamstring peak torque at POST0, POST15 and POST30 (p<0.05) and a reduced functional HQ ratio (Hecc/Qcon) at POST15 and POST30 (p<0.05). Additionally, a more extended knee angle at POST30 (p<0.05) and increased knee internal rotation angle at POST0 and POST15 (p<0.05) were found in a single-leg hop. SAFT(5) altered landing strategies associated with increased ACL injury risk and similar to observations from match simulations. Our findings therefore support the utility of a high-intensity exercise protocol such as SAFT(5) to strengthen injury screening tests and to include in prospective cohort studies where time constraints apply. PMID:26509378

  5. The Effects of Acute Intense Physical Exercise on Postural Stability in Children With Cerebral Palsy.

    PubMed

    Leineweber, Matthew J; Wyss, Dominik; Dufour, Sophie-Krystale; Gane, Claire; Zabjek, Karl; Bouyer, Laurent J; Maltais, Désirée B; Voisin, Julien I; Andrysek, Jan

    2016-07-01

    This study evaluated the effects of intense physical exercise on postural stability of children with cerebral palsy (CP). Center of pressure (CoP) was measured in 9 typically developing (TD) children and 8 with CP before and after a maximal aerobic shuttle-run test (SRT) using a single force plate. Anteroposterior and mediolateral sway velocities, sway area, and sway regularity were calculated from the CoP data and compared between pre- and postexercise levels and between groups. Children with CP demonstrated significantly higher pre-SRT CoP velocities than TD children in the sagittal (18.6 ± 7.6 vs. 6.75 1.78 m/s) and frontal planes (15.4 ± 5.3 vs. 8.04 ± 1.51 m/s). Post-SRT, CoP velocities significantly increased for children with CP in the sagittal plane (27.0 ± 1.2 m/s), with near-significant increases in the frontal plane (25.0 ± 1.5m/s). Similarly, children with CP evidenced larger sway areas than the TD children both pre- and postexercise. The diminished postural stability in children with CP after short but intense physical exercise may have important implications including increased risk of falls and injury. PMID:27623610

  6. Energy cost, exercise intensity, and gait efficiency of standard versus rocker-bottom axillary crutch walking.

    PubMed

    Nielsen, D H; Harris, J M; Minton, Y M; Motley, N S; Rowley, J L; Wadsworth, C T

    1990-08-01

    The purpose of this study was to investigate differences in selected biomechanical and physiological measurements and subjective preferences for ambulation with the standard single-tip axillary crutch versus the rocker-bottom-type axillary crutch. Self-selected walking velocities (S-SWVs) and stride length for each crutch type were determined for a two-point, non-weight-bearing, swing-through gait in 24 healthy volunteers. Relative exercise intensity, oxygen uptake (VO2), and gait efficiency were assessed for each crutch type at both S-SWVs. Subjects negotiated two architectural barriers (stairs and ramp) and completed a subjective questionnaire concerning crutch preferences. Walking with either crutch type resulted in slower S-SWVs, greater VO2, higher relative exercise intensity, and reduced gait efficiency compared with values for normal unassisted ambulation. An analysis of variance for these variables revealed nonsignificant between-crutch differences. Based on the subjective data, a preference for the standard single-tip crutch was evident. Within the scope of the study, the results supported no apparent advantage relative to energy expenditure to using the rocker-bottom crutch.

  7. Intense basketball-simulated exercise induces muscle damage in men with elevated anterior compartment pressure.

    PubMed

    Kostopoulos, Nikos; Fatouros, Ioannis G; Siatitsas, Ioannis; Baltopoulos, Panagiotis; Kambas, Antonios; Jamurtas, Athanasios Z; Fotinakis, Panagiotis

    2004-08-01

    The purpose of the present investigation was to examine the levels of muscle soreness, muscle damage, and performance output in men with (S, n = 24) or without (A, n = 24) chronic compartment syndrome (CACS)-related symptoms after an intense 10-minute basketball-simulated exercise. Anterior compartment pressure (ICP), muscle soreness perception, creatine kinase (CK) and lactate dehydrogenase (LDH) activities, myoglobin (Mb) concentration, leg strength, and knee joint range of motion (KJRM) were measured at rest, immediately after exercise, and at 24, 48, 72 and 96 hours postexercise (ICP was also measured at 5, 15, and 30 minutes postexercise). ICP, muscle soreness, CK, LDH, and myoglobin increased (p < 0.05) immediately postexercise and during the next 4 days of recovery in both groups. However, S demonstrated a far more pronounced and prolonged (p < 0.05) response than A. Leg strength and KJRM declined (p < 0.05) in both groups, but S demonstrated a greater (p < 0.05) performance deterioration than A. The results of this study suggest that intense basketball-simulated exercise increases ICP, muscle soreness, and indices of muscle damage with a concomitant decrease of performance. Men with CACS-related symptoms and/or history appear more sensitive to muscle damage and soreness than asymptomatic men, probably due to a compromised blood flow to the muscle producing fluid shifts from vascular to interstitial space and further increasing compartment pressure and muscle cell disruption. Results of the present investigation provide evidence to support proper diagnosis, monitoring, care, and preventive measures for symptomatic individuals prior to participation in activities such as basketball.

  8. 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.

  9. 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. PMID:25636207

  10. The diurnal patterns of cortisol and dehydroepiandrosterone in relation to intense aerobic exercise in recreationally trained soccer players.

    PubMed

    Labsy, Z; Prieur, F; Le Panse, B; Do, M C; Gagey, O; Lasne, F; Collomp, K

    2013-03-01

    Diurnal patterns of cortisol and dehydroepiandrosterone (DHEA) secretion, the two main peripheral secretory products of the hypothalamic-pituitary-adrenal neuroendocrine stress axis, have been well characterized in rest conditions but not in relation to physical exercise. The purpose of this investigation was therefore to determine the effects of an intense 90-min aerobic exercise on the waking diurnal cortisol and DHEA cycles on three separate days [without exercise, with morning exercise (10:00-11:30 h), and with afternoon exercise (14:00-15:30 h)] in nine recreationally trained soccer players. Saliva samples were collected at awakening, 30 min after awakening, and then every 2 h from 08:00 to 22:00 h. A burst of secretory activity was found for cortisol (p < 0.01) but not for DHEA after awakening. Overall, diurnal decline for both adrenal steroids was observed on resting and exercise days under all conditions. However, there was a significant increase in salivary cortisol concentrations on the morning-exercise and afternoon-exercise days at, respectively, 12:00 h (p < 0.05) and 16:00 h (p < 0.01), versus the other trials. This acute response to exercise was not evident for DHEA. The results of this investigation indicate that 90 min of intense aerobic exercise does not affect the circadian pattern of salivary adrenal steroids in recreationally trained athletes over a 16-h waking period, despite a transitory increase in post-exercise cortisol concentration. Further studies are necessary to determine whether these results are applicable to elite athletes or patients with cortisol or DHEA deficiency.

  11. Exercise and improved insulin sensitivity in older women: evidence of the enduring benefits of higher intensity training.

    PubMed

    DiPietro, Loretta; Dziura, James; Yeckel, Catherine W; Neufer, P Darrell

    2006-01-01

    Few studies have compared the relative benefits of moderate- vs. higher intensity exercise training on improving insulin sensitivity in older people while holding exercise volume constant. Healthy older (73 +/- 10 yr) women (N = 25) who were inactive, but not obese, were randomized into one of three training programs (9-mo duration): 1) high-intensity [80% peak aerobic capacity (V(O2)peak); T(H)] aerobic training; 2) moderate-intensity (65% V(O2)peak; T(M)) aerobic training; or 3) low-intensity (stretching) placebo control (50% V(O2)peak); C(TB)). Importantly, exercise volume (300 kcal/session) was held constant for subjects in both the T(H) and the T(M) groups. V(O2)peak was determined by using a graded exercise challenge on a treadmill. Total body fat and lean mass were determined with dual-energy X-ray absorptiometry. The rate of insulin-stimulated glucose utilization as well as the suppression of lipolysis were determined approximately 72 h after the final exercise bout by using a two-step euglycemic-hyperinsulinemic clamp. We observed improved glucose utilization at the higher insulin dose with training, but these improvements were statistically significant only in the T(H) (21%; P = 0.02) compared with the T(M) (16%; P = 0.17) and C(TB) (8%; P = 0.37) groups and were observed without changes in either body composition or V(O2)peak. Likewise in the T(H) group, we detected a significant improvement in insulin-stimulated suppression (%) of adipose tissue lipolysis at the low-insulin dose (38-55%, P < 0.05). Our findings suggest that long-term higher intensity exercise training provides more enduring benefits to insulin action compared with moderate- or low-intensity exercise, likely due to greater transient effects.

  12. The Accumulative Effect of Concentric-Biased and Eccentric-Biased Exercise on Cardiorespiratory and Metabolic Responses to Subsequent Low-Intensity Exercise: A Preliminary Study

    PubMed Central

    Gavin, James Peter; Myers, Stephen; Willems, Mark Elisabeth Theodorus

    2015-01-01

    The study investigated the accumulative effect of concentric-biased and eccentric-biased exercise on cardiorespiratory, metabolic and neuromuscular responses to low-intensity exercise performed hours later. Fourteen young men cycled at low-intensity (~60 rpm at 50% maximal oxygen uptake) for 10 min before, and 12 h after: concentric-biased, single-leg cycling exercise (CON) (performed ~19:30 h) and eccentric-biased, double-leg knee extension exercise (ECC) (~06:30 h the following morning). Respiratory measures were sampled breath-by-breath, with oxidation values derived from stoichiometry equations. Knee extensor neuromuscular function was assessed before and after CON and ECC. Cardiorespiratory responses during low-intensity cycling were unchanged by accumulative CON and ECC. The RER was lower during low-intensity exercise 12 h after CON and ECC (0.88 ± 0.08), when compared to baseline (0.92 ± 0.09; p = 0.02). Fat oxidation increased from baseline (0.24 ± 0.2 g·min−1) to 12 h after CON and ECC (0.39 ± 0.2 g·min−1; p = 0.01). Carbohydrate oxidation decreased from baseline (1.59 ± 0.4 g·min−1) to 12 h after CON and ECC (1.36 ± 0.4 g·min−1; p = 0.03). These were accompanied by knee extensor force loss (right leg: −11.6%, p < 0.001; left leg: −10.6%, p = 0.02) and muscle soreness (right leg: 2.5 ± 0.9, p < 0.0001; left leg: 2.3 ± 1.2, p < 0.01). Subsequent concentric-biased and eccentric-biased exercise led to increased fat oxidation and decreased carbohydrate oxidation, without impairing cardiorespiration, during low-intensity cycling. An accumulation of fatiguing and damaging exercise increases fat utilisation during low intensity exercise performed as little as 12 h later. PMID:26839613

  13. The Accumulative Effect of Concentric-Biased and Eccentric-Biased Exercise on Cardiorespiratory and Metabolic Responses to Subsequent Low-Intensity Exercise: A Preliminary Study.

    PubMed

    Gavin, James Peter; Myers, Stephen; Willems, Mark Elisabeth Theodorus

    2015-12-22

    The study investigated the accumulative effect of concentric-biased and eccentric-biased exercise on cardiorespiratory, metabolic and neuromuscular responses to low-intensity exercise performed hours later. Fourteen young men cycled at low-intensity (~60 rpm at 50% maximal oxygen uptake) for 10 min before, and 12 h after: concentric-biased, single-leg cycling exercise (CON) (performed ~19:30 h) and eccentric-biased, double-leg knee extension exercise (ECC) (~06:30 h the following morning). Respiratory measures were sampled breath-by-breath, with oxidation values derived from stoichiometry equations. Knee extensor neuromuscular function was assessed before and after CON and ECC. Cardiorespiratory responses during low-intensity cycling were unchanged by accumulative CON and ECC. The RER was lower during low-intensity exercise 12 h after CON and ECC (0.88 ± 0.08), when compared to baseline (0.92 ± 0.09; p = 0.02). Fat oxidation increased from baseline (0.24 ± 0.2 g·min(-1)) to 12 h after CON and ECC (0.39 ± 0.2 g·min(-1); p = 0.01). Carbohydrate oxidation decreased from baseline (1.59 ± 0.4 g·min(-1)) to 12 h after CON and ECC (1.36 ± 0.4 g·min(-1); p = 0.03). These were accompanied by knee extensor force loss (right leg: -11.6%, p < 0.001; left leg: -10.6%, p = 0.02) and muscle soreness (right leg: 2.5 ± 0.9, p < 0.0001; left leg: 2.3 ± 1.2, p < 0.01). Subsequent concentric-biased and eccentric-biased exercise led to increased fat oxidation and decreased carbohydrate oxidation, without impairing cardiorespiration, during low-intensity cycling. An accumulation of fatiguing and damaging exercise increases fat utilisation during low intensity exercise performed as little as 12 h later.

  14. Exercise intensity and load during different races in youth and junior cyclists.

    PubMed

    Rodríguez-Marroyo, Jose A; Pernía, Raúl; Cejuela, Roberto; García-López, Juan; Llopis, Juan; Villa, José G

    2011-02-01

    This study analyzed and compared the exercise intensity exerted by Youth and Junior cyclists in single-day and stage races. Heart rate was measured during the races and categorized according to 3 intensity zones: Z1 (below the ventilatory threshold [VT]), Z2 (between the VT and the respiratory compensation threshold [RCT]), and Z3 (above the RCT). The training impulse (TRIMP) was calculated by multiplying the sum of the time spent in each zone by 1, 2, and 3, respectively. Time spent in Z1, Z2, and daily TRIMP were significantly higher (p < 0.05) in Junior than in Youth in both single-day races (21.6 ± 1.9 min vs. 14.8 ± 1.6 min, 55.4 ± 2.3 min vs. 34.7 ± 1.9 min, and 257 ± 6 vs. 194 ± 6, respectively) and stage races (49.2 ± 3.4 min vs. 23.5 ± 4.7 min, 51.2 ± 2.6 min vs. 35.3 ± 3.7 min, and 201 ± 10 vs. 147 ± 7, respectively). In Youth and Junior, time and percentage time spent in Z3 and daily TRIMP were also significantly higher (p < 0.05) in single-day races (39.0 ± 1.9 min, 40.2 ± 1.9% and 225 ± 7) than in stage races (13.9 ± 1.8 min, 15.2 ± 1.8% and 174 ± 8). In conclusion, the present study showed that races in both Youth and Junior categories are highly demanding and that their intensity and exercise load are related to the total race duration.

  15. Does low serum carnosinase activity favor high-intensity exercise capacity?

    PubMed

    Baguet, Audrey; Everaert, Inge; Yard, Benito; Peters, Verena; Zschocke, Johannes; Zutinic, Ana; De Heer, Emile; Podgórski, Tomasz; Domaszewska, Katarzyna; Derave, Wim

    2014-03-01

    Given the ergogenic properties of β-alanyl-L-histidine (carnosine) in skeletal muscle, it can be hypothesized that elevated levels of circulating carnosine could equally be advantageous for high-intensity exercises. Serum carnosinase (CN1), the enzyme hydrolyzing the dipeptide, is highly active in the human circulation. Consequently, dietary intake of carnosine usually results in rapid degradation upon absorption, yet this is less pronounced in subjects with low CN1 activity. Therefore, acute carnosine supplementation before high-intensity exercise could be ergogenic in these subjects. In a cross-sectional study, we determined plasma CN1 activity and content in 235 subjects, including 154 untrained controls and 45 explosive and 36 middle- to long-distance elite athletes. In a subsequent double-blind, placebo-controlled, crossover study, 12 men performed a cycling capacity test at 110% maximal power output (CCT 110%) following acute carnosine (20 mg/kg body wt) or placebo supplementation. Blood samples were collected to measure CN1 content, carnosine, and acid-base balance. Both male and female explosive athletes had significantly lower CN1 activity (14% and 21% lower, respectively) and content (30% and 33% lower, respectively) than controls. Acute carnosine supplementation resulted only in three subjects in carnosinemia. The CCT 110% performance was not improved after carnosine supplementation, even when accounting for low/high CN1 content. No differences were found in acid-base balance, except for elevated resting bicarbonate following carnosine supplementation and in low CN1 subjects. In conclusion, explosive athletes have lower serum CN1 activity and content compared with untrained controls, possibly resulting from genetic selection. Acute carnosine supplementation does not improve high-intensity performance.

  16. Pre-exercise low-level laser therapy improves performance and levels of oxidative stress markers in mdx mice subjected to muscle fatigue by high-intensity exercise.

    PubMed

    Silva, Andreia Aparecida de Oliveira; Leal-Junior, Ernesto Cesar Pinto; D'Avila, Katia de Angelis Lobo; Serra, Andrey Jorge; Albertini, Regiane; França, Cristiane Miranda; Nishida, Joen Akemi; de Carvalho, Paulo de Tarso Camillo

    2015-08-01

    This study was designed to determine if the levels of oxidative stress markers are influenced by low-level laser therapy (LLLT) in mdx mice subjected to high-intensity exercise training on an electric treadmill. We used 21 C57BL/10ScSn-Dmdmdx/J mice and 7 C57BL/10ScSn mice, all aged 4 weeks. The mice were divided into four groups: a positive control group of normal, wild-type mice (WT); a negative control group of untreated mdx mice; a group of mdx mice that underwent forced high-intensity exercise on a treadmill (mdx fatigue); and another group of mdx mice with the same characteristics that were treated with LLLT at a single point on the gastrocnemius muscle of the hind paw and underwent forced high-intensity exercise on a treadmill. The mdx mice treated with LLLT showed significantly lower levels of creatine kinase (CK) and oxidative stress than mdx mice that underwent forced high-intensity exercise on a treadmill. The activities of the antioxidant enzyme superoxide dismutase (SOD) were higher in control mdx mice than in WT mice. LLLT also significantly reduced the level of this marker. LLLT had a beneficial effect also on the skeletal muscle performance of mdx mice. However, the single application of LLLT and the dose parameters used in this study were not able to change the morphology of a dystrophic muscle.

  17. Mild-to-moderate intensity exercise improves cardiac autonomic drive in type 2 diabetes

    PubMed Central

    Goit, Rajesh Kumar; Paudel, Bishnu Hari; Khadka, Rita; Roy, Roshan Kumar; Shrewastwa, Mukesh Kumar

    2014-01-01

    Aims/Introduction The aim of the present study was to determine the effect of moderate aerobic exercise on cardiac autonomic function in type 2 diabetic patients. Materials and Methods Heart rate variability of 20 patients with type 2 diabetes was assessed. Resting electrocardiogram for the heart rate variability analysis at spontaneous respiration was recorded for 5 min in the supine position before and after 6 months of supervised aerobic training given three times per week. Results In time domain measures, the square root of the mean of the sum of the squares of differences between adjacent R-R intervals (RMSSD; 29.7 [26–34.5] vs 46.4 [29.8–52.2] ms, P = 0.023) and the percentage of consecutive RR intervals that differ by more than 50 ms (pNN50; 10.7 [5.5–12.7] vs 26.1 [6.6–37.2]%, P = 0.025] were significantly increased after exercise. In frequency domain measures, low frequency (62.4 [59.1–79.2] vs 37 [31.3–43.3] nu, P = 0.003) and low frequency/high frequency (1.67 [1.44–3.8] vs 0.58 [0.46–0.59]%, P = 0.009) were significantly decreased, whereas high frequency (95 [67–149] vs 229 [98–427] ms2, P = 0.006) and high frequency (37.6 [20.8–40.9] vs 63 [56.7–68.7] normalized units, P = 0.003) were significantly increased after exercise. In a Poincaré plot, standard deviation perpendicular to the line of the Poincaré plot (SD1; 21.3 [18.5–24.8]–33.1 [21.5–37.2] ms, P = 0.027) was significantly increased after exercise. Conclusions These data suggest that three times per week moderate intensity aerobic exercise for 6 months improves cardiac rhythm regulation as measured by heart rate variability in type 2 diabetic patients. PMID:25422774

  18. Effect of Muscle-Damaging Eccentric Exercise on Running Kinematics and Economy for Running at Different Intensities.

    PubMed

    Satkunskienė, Danguolė; Stasiulis, Arvydas; Zaičenkovienė, Kristina; Sakalauskaitė, Raminta; Rauktys, Donatas

    2015-09-01

    The objective of this study was to explore the changes in running kinematics and economy during running at different intensities 1 and 24 hours after a muscle-damaging bench-stepping exercise. Healthy, physically active adult women were recruited for this study. The subjects' running kinematics, heart rate, gas exchange, minute ventilation, and perceived exertion were continuously recorded during the increasing-intensity running test on a treadmill for different testing conditions: a control condition and 1 and 24 hours after the bench-stepping exercise test. Two muscle damage markers, muscle soreness and blood creatine kinase (CK) activity, were measured before and 24 hours after the stepping exercise. Muscle soreness and blood CK activity were significantly altered (exact p ≤ 0.05, Monte Carlo test) 24 hours after the bench-stepping exercise. The stride length, stride frequency, and support time at different running intensities did not change. Twenty-four hours after the previous step exercise, ankle dorsiflexion in the support phase was significantly higher during severe-intensity running, the range of knee flexion at the stance phase was significantly lower during moderate-intensity running, and knee flexion at the end of the amortization phase was significantly lower during heavy-intensity running compared with the control values (exact p ≤ 0.05, Monte Carlo test). The running economy at moderate and heavy intensities, maximum ventilation, and maximum heart rate did not change. We conclude that, given moderate soreness in the calf muscles 24 hours after eccentric exercise, the running kinematics are slightly but significantly changed without a detectable effect on running economy.

  19. Intermittent and continuous high-intensity exercise training induce similar acute but different chronic muscle adaptations.

    PubMed

    Cochran, Andrew J R; Percival, Michael E; Tricarico, Steven; Little, Jonathan P; Cermak, Naomi; Gillen, Jenna B; Tarnopolsky, Mark A; Gibala, Martin J

    2014-05-01

    High-intensity interval training (HIIT) performed in an 'all-out' manner (e.g. repeated Wingate tests) is a time-efficient strategy to induce skeletal muscle remodelling towards a more oxidative phenotype. A fundamental question that remains unclear, however, is whether the intermittent or 'pulsed' nature of the stimulus is critical to the adaptive response. In study 1, we examined whether the activation of signalling cascades linked to mitochondrial biogenesis was dependent on the manner in which an acute high-intensity exercise stimulus was applied. Subjects performed either four 30 s Wingate tests interspersed with 4 min of rest (INT) or a bout of continuous exercise (CONT) that was matched for total work (67 ± 7 kJ) and which required ∼4 min to complete as fast as possible. Both protocols elicited similar increases in markers of adenosine monophosphate-activated protein kinase (AMPK) and p38 mitogen-activated protein kinase activation, as well as Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) mRNA expression (main effects for time, P ≤ 0.05). In study 2, we determined whether 6 weeks of the CONT protocol (3 days per week) would increase skeletal muscle mitochondrial content to a similar extent to what we have previously reported after 6 weeks of INT. Despite similar acute signalling responses to the CONT and INT protocols, training with CONT did not increase the maximal activity or protein content of a range of mitochondrial markers. However, peak oxygen uptake was higher after CONT training (from 45.7 ± 5.4 to 48.3 ± 6.5 ml kg(-1) min(-1); P < 0.05) and 250 kJ time trial performance was improved (from 26:32 ± 4:48 to 23:55 ± 4:16 min:s; P < 0.001) in our recreationally active participants. We conclude that the intermittent nature of the stimulus is important for maximizing skeletal muscle adaptations to low-volume, all-out HIIT. Despite the lack of skeletal muscle mitochondrial adaptations

  20. Low-intensity and moderate exercise training improves autonomic nervous system activity imbalanced by postnatal early overfeeding in rats

    PubMed Central

    2014-01-01

    Background Postnatal early overfeeding and physical inactivity are serious risk factors for obesity. Physical activity enhances energy expenditure and consumes fat stocks, thereby decreasing body weight (bw). This study aimed to examine whether low-intensity and moderate exercise training in different post-weaning stages of life is capable of modulating the autonomic nervous system (ANS) activity and inhibiting perinatal overfeeding-induced obesity in rats. Methods The obesity-promoting regimen was begun two days after birth when the litter size was adjusted to 3 pups (small litter, SL) or to 9 pups (normal litter, NL). The rats were organized into exercised groups as follows: from weaning until 90-day-old, from weaning until 50-day-old, or from 60- until 90-days-old. All experimental procedures were performed just one day after the exercise training protocol. Results The SL-no-exercised (SL-N-EXE) group exhibited excess weight and increased fat accumulation. We also observed fasting hyperglycemia and glucose intolerance in these rats. In addition, the SL-N-EXE group exhibited an increase in the vagus nerve firing rate, whereas the firing of the greater splanchnic nerve was not altered. Independent of the timing of exercise and the age of the rats, exercise training was able to significantly blocks obesity onset in the SL rats; even SL animals whose exercise training was stopped at the end of puberty, exhibited resistance to obesity progression. Fasting glycemia was maintained normal in all SL rats that underwent the exercise training, independent of the period. These results demonstrate that moderate exercise, regardless of the time of onset, is capable on improve the vagus nerves imbalanced tonus and blocks the onset of early overfeeding-induced obesity. Conclusions Low-intensity and moderate exercise training can promote the maintenance of glucose homeostasis, reduces the large fat pad stores associated to improvement of the ANS activity in adult rats that were

  1. Adrenal cortical responses to high-intensity, short rest, resistance exercise in men and women.

    PubMed

    Szivak, Tunde K; Hooper, David R; Dunn-Lewis, Courtenay; Comstock, Brett A; Kupchak, Brian R; Apicella, Jenna M; Saenz, Catherine; Maresh, Carl M; Denegar, Craig R; Kraemer, William J

    2013-03-01

    Commercial high-intensity, short rest (HI/SR) protocols have been anecdotally postured to be extremely demanding. However, limited prior studies have demonstrated HI/SR protocols to produce hyperreactions in metabolic and adrenal function; thus, the purpose of this study was to evaluate the physiological effects of an acute, high-intensity (75% 1-repetition maximum), short rest resistance exercise protocol. Nine trained men (age: 23.5 ± 3.5 years, height: 172.4 ± 4.0 cm, weight: 77.8 ± 8.8 kg) and 9 trained women (age: 22.9 ± 2.0 years, height: 168.4 ± 9.4 cm, weight: 68.5 ± 10.4 kg) participated in the HI/SR protocol, which consisted of a descending pyramid scheme of back squat, bench press, and deadlift, beginning with 10 repetitions of each, then 9, then 8, and so on until 1 repetition on the final set. Significant time effects were observed in lactate (immediate post [IP], +15, +60) and cortisol (IP, +15, +60) response. Significant sex effects were observed in lactate response (IP, +15) but not in cortisol response. Total work was higher in men and influenced magnitude of increase in lactate but not cortisol. No significant sex differences were noted in time to completion, average relative intensity, heart rate response or rating of perceived exertion scores. Highest lactate (IP men: 17.3 mmol·L(-1); IP women: 13.8 mmol·L(-1)) and cortisol (+15 men: 1,860.2 nmol·L(-1); +15 women: 1,831.7 nmol·L(-1)) values were considerably greater than those produced in typical resistance exercise programs, confirming that relative intensity and rest period length are important factors determining magnitude of metabolic and adrenal stress. Practical applications for the coach include cautious implementation of HI/SR protocols, as long-term sequential use may promote overtraining. A gradual reduction in rest interval length with concurrent gradual increase in intensity should be used to minimize potential negative effects such as nonfunctional overreaching. PMID

  2. Influence of Differences in Exercise-intensity and Kilograms/Set on Energy Expenditure During and After Maximally Explosive Resistance Exercise

    PubMed Central

    MAZZETTI, SCOTT A.; WOLFF, CHRISTOPHER; COLLINS, BRITTANY; KOLANKOWSKI, MICHAEL T.; WILKERSON, BRITTANY; OVERSTREET, MATTHEW; GRUBE, TROY

    2011-01-01

    With resistance exercise, greater intensity typically elicits increased energy expenditure, but heavier loads require that the lifter perform more sets of fewer repetitions, which alters the kilograms lifted per set. Thus, the effect of exercise-intensity on energy expenditure has yielded varying results, especially with explosive resistance exercise. This study was designed to examine the effect of exercise-intensity and kilograms/set on energy expenditure during explosive resistance exercise. Ten resistance-trained men (22±3.6 years; 84±6.4 kg, 180±5.1 cm, and 13±3.8 %fat) performed squat and bench press protocols once/week using different exercise-intensities including 48% (LIGHT-48), 60% (MODERATE-60), and 72% of 1-repetition-maximum (1-RM) (HEAVY-72), plus a no-exercise protocol (CONTROL). To examine the effects of kilograms/set, an additional protocol using 72% of 1-RM was performed (HEAVY-72MATCHED) with kilograms/set matched with LIGHT-48 and MODERATE-60. LIGHT-48 was 4 sets of 10 repetitions (4×10); MODERATE-60 4×8; HEAVY-72 5×5; and HEAVY-72MATCHED 4×6.5. Eccentric and concentric repetition speeds, ranges-of-motion, rest-intervals, and total kilograms were identical between protocols. Expired air was collected continuously throughout each protocol using a metabolic cart, [Blood lactate] using a portable analyzer, and bench press peak power were measured. Rates of energy expenditure were significantly greater (p≤0.05) with LIGHT-48 and HEAVY-72MATCHED than HEAVY-72 during squat (7.3±0.7; 6.9±0.6 > 6.1±0.7 kcal/min), bench press (4.8±0.3; 4.7±0.3 > 4.0±0.4 kcal/min), and +5min after (3.7±0.1; 3.7±0.2 > 3.3±0.3 kcal/min), but there were no significant differences in total kcal among protocols. Therefore, exercise-intensity may not effect energy expenditure with explosive contractions, but light loads (~50% of 1-RM) may be preferred because of higher rates of energy expenditure, and since heavier loading requires more sets with lower

  3. High Intensity Resistive and Rowing Exercise Countermeasures Do Not Prevent Orthostatic Intolerance Following 70 Days of Bed Rest

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    More than 60% of US astronauts participating in Mir and early International Space Station missions (greater than 5 months) were unable to complete a 10-min 80 deg head-up tilt test on landing day. This high incidence of post-spaceflight orthostatic intolerance may be related to limitations of the inflight exercise hardware that prevented high intensity training. PURPOSE: This study sought to determine if a countermeasure program that included intense lower-body resistive and rowing exercises designed to prevent cardiovascular and musculoskeletal deconditioning during 70 days of 6 deg head-down tilt bed rest (BR), a spaceflight analog, also would protect against post- BR orthostatic intolerance. METHODS: Sixteen males participated in this study and performed no exercise (Control, n=10) or performed an intense supine exercise protocol with resistive and aerobic components (Exercise, n=6). On 3 days/week, exercise subjects performed lower body resistive exercise and a 30-min continuous bout of rowing (greater than or equal to 75% max heart rate). On 3 other days/week, subjects performed only high-intensity, interval-style rowing. Orthostatic intolerance was assessed using a 15-min 80 deg head-up tilt test performed 2 days (BR-2) before and on the last day of BR (BR70). Plasma volume was measured using a carbon monoxide rebreathing technique on BR-3 and before rising on the first recovery day (BR+0). RESULTS: Following 70 days of BR, tilt tolerance time decreased significantly in both the Control (BR-2: 15.0 +/- 0.0, BR70: 9.9 +/- 4.6 min, mean +/- SD) and Exercise (BR-2: 12.2 +/- 4.7, BR70: 4.9 +/- 1.9 min) subjects, but the decreased tilt tolerance time was not different between groups (Control: -34 +/- 31, Exercise: -56 +/- 16%). Plasma volume also decreased (Control: -0.56 +/- 0.40, Exercise: -0.48 +/- 0.33 L) from pre to post-BR, with no differences between groups (Control: -18 +/- 11%, Exerciser: -15 +/-1 0%). CONCLUSIONS: These findings confirm previous reports

  4. Exercise Intensity Modulates Glucose-Stimulated Insulin Secretion when Adjusted for Adipose, Liver and Skeletal Muscle Insulin Resistance

    PubMed Central

    Malin, Steven K.; Rynders, Corey A.; Weltman, Judy Y.; Barrett, Eugene J.; Weltman, Arthur

    2016-01-01

    Little is known about the effects of exercise intensity on compensatory changes in glucose-stimulated insulin secretion (GSIS) when adjusted for adipose, liver and skeletal muscle insulin resistance (IR). Fifteen participants (8F, Age: 49.9±3.6yr; BMI: 31.0±1.5kg/m2; VO2peak: 23.2±1.2mg/kg/min) with prediabetes (ADA criteria, 75g OGTT and/or HbA1c) underwent a time-course matched Control, and isocaloric (200kcal) exercise at moderate (MIE; at lactate threshold (LT)), and high-intensity (HIE; 75% of difference between LT and VO2peak). A 75g OGTT was conducted 1 hour post-exercise/Control, and plasma glucose, insulin, C-peptide and free fatty acids were determined for calculations of skeletal muscle (1/Oral Minimal Model; SMIR), hepatic (HOMAIR), and adipose (ADIPOSEIR) IR. Insulin secretion rates were determined by deconvolution modeling for GSIS, and disposition index (DI; GSIS/IR; DISMIR, DIHOMAIR, DIADIPOSEIR) calculations. Compared to Control, exercise lowered SMIR independent of intensity (P<0.05), with HIE raising HOMAIR and ADIPOSEIR compared with Control (P<0.05). GSIS was not reduced following exercise, but DIHOMAIR and DIADIPOSEIR were lowered more following HIE compared with Control (P<0.05). However, DISMIR increased in an intensity based manner relative to Control (P<0.05), which corresponded with lower post-prandial blood glucose levels. Taken together, pancreatic insulin secretion adjusts in an exercise intensity dependent manner to match the level of insulin resistance in skeletal muscle, liver and adipose tissue. Further work is warranted to understand the mechanism by which exercise influences the cross-talk between tissues that regulate blood glucose in people with prediabetes. PMID:27111219

  5. High Intensity Physical Exercise and Pain in the Neck and Upper Limb among Slaughterhouse Workers: Cross-Sectional Study

    PubMed Central

    Sundstrup, Emil; Jakobsen, Markus D.; Jay, Kenneth; Brandt, Mikkel; Andersen, Lars L.

    2014-01-01

    Slaughterhouse work involves a high degree of repetitive and forceful upper limb movements and thus implies an elevated risk of work-related musculoskeletal disorders. High intensity strength training effectively rehabilitates musculoskeletal disorders among sedentary employees, but less is known about the effect among workers with repetitive and forceful work demands. Before performing randomized controlled trials it may be beneficial to assess the cross-sectional connection between exercise and musculoskeletal pain. We investigated the association between high intensity physical exercise and pain among 595 slaughterhouse workers in Denmark, Europe. Using logistic regression analyses, odds ratios for pain and work disability as a function of physical exercise, gender, age, BMI, smoking, and job position were estimated. The prevalence of pain in the neck, shoulder, elbow, and hand/wrist was 48%, 60%, 40%, and 52%, respectively. The odds for experiencing neck pain were significantly lower among slaughterhouse workers performing physical exercise (OR = 0.70, CI: 0.49–0.997), whereas the odds for pain in the shoulders, elbow, or hand/wrist were not associated with exercise. The present study can be used as general reference of pain in the neck and upper extremity among slaughterhouse workers. Future studies should investigate the effect of high intensity physical exercise on neck and upper limb pain in slaughterhouse workers. PMID:24527440

  6. Endurance capacity and high-intensity exercise performance responses to a high fat diet.

    PubMed

    Fleming, Jesse; Sharman, Matthew J; Avery, Neva G; Love, Dawn M; Gómez, Ana L; Scheett, Timothy P; Kraemer, William J; Volek, Jeff S

    2003-12-01

    The effects of adaptation to a high-fat diet on endurance performance are equivocal, and there is little data regarding the effects on high-intensity exercise performance. This study examined the effects of a high-fat/moderate protein diet on submaximal, maximal, and supramaximal performance. Twenty non-highly trained men were assigned to either a high-fat/moderate protein (HFMP; 61% fat diet) (n = 12) or a control (C; 25% fat) group (n = 8). A maximal oxygen consumption test, two 30-s Wingate anaerobic tests, and a 45-min timed ride were performed before and after 6 weeks of diet and training. Body mass decreased significantly (-2.2 kg; p < or = .05) in HFMP subjects. Maximal oxygen consumption significantly decreased in the HFMP group (3.5 +/- 0.14 to 3.27 +/- 0.09 L x min(-1)) but was unaffected when corrected for body mass. Perceived exertion was significantly higher during this test in the HFMP group. Main time effects indicated that peak and mean power decreased significantly during bout 1 of the Wingate sprints in the HFMP (-10 and -20%, respectively) group but not the C (-8 and -16%, respectively) group. Only peak power was lower during bout 1 in the HFMP group when corrected for body mass. Despite significantly reduced RER values in the HFMP group during the 45-min cycling bout, work output was significantly decreased (-18%). Adaptation to a 6-week HFMP diet in non-highly trained men resulted in increased fat oxidation during exercise and small decrements in peak power output and endurance performance. These deleterious effects on exercise performance may be accounted for in part by a reduction in body mass and/or increased ratings of perceived exertion.

  7. Redesigning an intensive insulin service for patients with type 1 diabetes: a patient consultation exercise

    PubMed Central

    Ozcan, Seyda; Rogers, Helen; Choudhary, Pratik; Amiel, Stephanie A; Cox, Alison; Forbes, Angus

    2013-01-01

    Context Providing effective support for patients in using insulin effectively is essential for good diabetes care. For that support to be effective it must reflect and attend to the needs of patients. Purpose To explore the perspectives of adult type 1 diabetes patients on their current diabetes care in order to generate ideas for creating a new patient centered intensive insulin clinic. Methods A multi-method approach was used, comprising: an observational exercise of current clinical care; three focus groups (n = 17); and a survey of service users (n = 419) to test the ideas generated from the observational exercise and focus groups (rating 1 to 5 in terms of importance). The ideas generated by the multi-method approach were organized thematically and mapped onto the Chronic Care Model (CCM). Results The themes and preferences for service redesign in relation to CCM components were: health care organization, there was an interest in having enhanced systems for sharing clinical information; self-management support, patients would like more flexible and easy to access resources and more help with diabetes technology and psychosocial support; delivery system design and clinical information systems, the need for greater integration of care and better use of clinic time; productive relationships, participants would like more continuity; access to health professionals, patient involvement and care planning. The findings from the patient survey indicate high preferences for most of the areas for service enhancement identified in the focus groups and observational exercise. Clinical feedback and professional continuity (median = 5, interquartile range = 1) were the most highly rated. Conclusion The patient consultation process had generated important ideas on how the clinical team and service can improve the care provided. Key areas for service development were: a stronger emphasis of collaborative care planning; improved patient choice in the use of health technology

  8. Low intensity peripheral muscle conditioning improves exercise tolerance and breathlessness in COPD.

    PubMed

    Clark, C J; Cochrane, L; Mackay, E

    1996-12-01

    This randomized, controlled study investigated the physiological effects of a specially designed 12 week programme of isolated conditioning of peripheral skeletal muscle groups. The programme required minimal infrastructure in order to allow continued rehabilitation at home after familiarization within hospital. Forty eight patients, aged 40-72 yrs with chronic obstructive pulmonary disease (COPD) (mean (SD) forced expiratory volume in one second (FEV1) 61 (27)% of predicted normal) were randomly allocated into training (n = 32) and control (n = 16) groups. Physiological assessments were performed before and after the 12 week study period, and included peripheral muscle endurance and strength, whole body endurance, maximal exercise capacity (maximum oxygen consumption (V'O2,max)) and lung function. The training group showed significant improvement in a variety of measures of upper and lower peripheral muscle performance, with no additional breathlessness. Whole body endurance measured by free arm treadmill walking increased by 6,372 (3,932-8,812) 3 (p < 0.001). Symptom-limited maximal V'O2 was unchanged. However, the training group showed a reduction in ventilatory equivalents for oxygen and carbon dioxide, both at peak exercise and at equivalent work rate (Wmax). In summary, low intensity isolated peripheral muscle conditioning is well-tolerated, simple and easy to perform at home. The various physiological benefits should enable patients across the range of severity of chronic obstructive pulmonary disease to improve daily functioning. PMID:8980974

  9. Intensity and physiological strain of competitive ultra-endurance exercise in humans.

    PubMed

    Lucas, Samuel J E; Anglem, Nat; Roberts, Warren S; Anson, J Greg; Palmer, Craig D; Walker, Robert J; Cook, Christian J; Cotter, James D

    2008-03-01

    The aim of this study was to determine the magnitude and pattern of intensity, and physiological strain, of competitive exercise performed across several days, as in adventure racing. Data were obtained from three teams of four athletes (7 males, 5 females; mean age 36 years, s = 11; cycling .VO(2 peak) 53.9 ml . kg(-1) . min(-1), s = 6.3) in an international race (2003 Southern Traverse; 96 - 116 h). Heart rates (HR) averaged 64% (95% confidence interval: +/- 4%) of heart rate range [%HRR = (HR - HR(min))/(HR(max) - HR(min)) x 100] during the first 12 h of racing, fell to 41% (+/-4%) by 24 h, and remained so thereafter. The level and pattern of heart rate were similar across teams, despite one leading and one trailing all other teams. Core temperature remained between 36.0 and 39.2 degrees C despite widely varying thermal stress. Venous samples, obtained before, during, and after the race, revealed increased neutrophil, monocyte and lymphocyte concentrations (P < 0.01), and increased plasma volume (25 +/- 10%; P < 0.01) with a stable sodium concentration. Standardized exercise tests, performed pre and post race, showed little change in the heart rate-work rate relationship (P = 0.53), but a higher perception of effort post race (P < 0.01). These results provide the first comprehensive report of physiological strain associated with adventure racing. PMID:18274945

  10. 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.

  11. Combined Low-Intensity Exercise and Ascorbic Acid Attenuates Kainic Acid-Induced Seizure and Oxidative Stress in Mice.

    PubMed

    Kim, Hee-Jae; Song, Wook; Jin, Eun Hee; Kim, Jongkyu; Chun, Yoonseok; An, Eung Nam; Park, Sok

    2016-05-01

    Physical exercise and vitamins such as ascorbic acid (ASC) have been recognized as an effective strategy in neuroprotection and neurorehabilitatioin. However, there is a need to find an efficient treatment regimen that includes ASC and low-intensity exercise to diminish the risk of overtraining and nutritional treatment by attenuating oxidative stress. In the present study, we investigated the combined effect of low-intensity physical exercise (EX) and ASC on kainic acid (KA)-induced seizure activity and oxidative stress in mice. The mice were randomly assigned into groups as follows: "KA only" (n = 11), "ASC + KA" (n = 11), "Ex + KA" (n = 11), "ASC + Ex + KA" (n = 11). In the present study, low intensity of swimming training period lasted 8 weeks and consisted of 30-min sessions daily (three times per week) without tail weighting. Although no preventive effect of low-intensity exercise or ASC on KA seizure occurrence was evident, there was a decrease of seizure activity, seizure development (latency to first seizures), and mortality in "ASC + Ex + KA" compared to "ASC + KA", "Ex + KA", and "KA only" group. In addition, a preventive synergistic coordination of low-intensity exercise and ASC was evident in glutathione peroxidase and superoxide dismutase activity compared to separate treatment. These results suggest that low-intensity exercise and ASC treatment have preventive effects on seizure activity and development with alternation of oxidative status. PMID:26646003

  12. 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. PMID:26791827

  13. The effects of high-intensity intermittent exercise training on cardiovascular response to mental and physical challenge.

    PubMed

    Heydari, Mehrdad; Boutcher, Yati N; Boutcher, Stephen H

    2013-02-01

    The purpose was to examine the effect of a 12-week exercise intervention on the cardiovascular and autonomic response of males to mental and physical challenge. Thirty four young overweight males were randomly assigned to either an exercise or control group. The exercise group completed a high-intensity intermittent exercise (HIIE) program three times per week for 12weeks. Cardiovascular response to the Stroop task was determined before and after the intervention by assessing heart rate (HR), stroke volume (SV), arterial stiffness, baroreflex sensitivity (BRS), and skeletal muscle blood flow. The exercise group improved their aerobic fitness levels by 17% and reduced their body weight by 1.6kg. Exercisers compared to controls experienced a significant reduction in HR (p<0.001) and a significant increase in SV (p<0.001) at rest and during Stroop and exercise. For exercisers, arterial stiffness significantly decreased at rest and during Stroop (p<0.01), whereas BRS was increased at rest and during Stroop (p<0.01). Forearm blood flow was significantly increased during the first two minutes of Stroop (p<0.05). HIIE induced significant cardiovascular and autonomic changes at rest and during mental and physical challenge after 12weeks of training. PMID:23220158

  14. Intense exercise increases circulating endocannabinoid and BDNF levels in humans--possible implications for reward and depression.

    PubMed

    Heyman, E; Gamelin, F-X; Goekint, M; Piscitelli, F; Roelands, B; Leclair, E; Di Marzo, V; Meeusen, R

    2012-06-01

    The endocannabinoid system is known to have positive effects on depression partly through its actions on neurotrophins, such as Brain-Derived Neurotrophic Factor (BDNF). As BDNF is also considered the major candidate molecule for exercise-induced brain plasticity, we hypothesized that the endocannabinoid system represents a crucial signaling system mediating the beneficial antidepressant effects of exercise. Here we investigated, in 11 healthy trained male cyclists, the effects of an intense exercise (60 min at 55% followed by 30 min at 75% W(max)) on plasma levels of endocannabinoids (anandamide, AEA and 2-arachidonoylglycerol, 2-AG) and their possible link with serum BDNF. AEA levels increased during exercise and the 15 min recovery (P<0.001), whereas 2-AG concentrations remained stable. BDNF levels increased significantly during exercise and then decreased during the 15 min of recovery (P<0.01). Noteworthy, AEA and BDNF concentrations were positively correlated at the end of exercise and after the 15 min recovery (r>0.66, P<0.05), suggesting that AEA increment during exercise might be one of the factors involved in exercise-induced increase in peripheral BDNF levels and that AEA high levels during recovery might delay the return of BDNF to basal levels. AEA production during exercise might be triggered by cortisol since we found positive correlations between these two compounds and because corticosteroids are known to stimulate endocannabinoid biosynthesis. These findings provide evidence in humans that acute exercise represents a physiological stressor able to increase peripheral levels of AEA and that BDNF might be a mechanism by which AEA influences the neuroplastic and antidepressant effects of exercise. PMID:22029953

  15. Comparison of chest pain, electrocardiographic changes and thallium-201 scintigraphy during varying exercise intensities in men with stable angina pectoris

    SciTech Connect

    Heller, G.V.; Ahmed, I.; Tilkemeier, P.L.; Barbour, M.M.; Garber, C.E. )

    1991-09-01

    This study was performed to evaluate the presence of angina pectoris, electrocardiographic changes and reversible thallium-201 defects resulting from 2 different levels of exercise in 19 patients with known coronary artery disease and evidence of exercise-induced ischemia. The exercise protocols consisted of a symptom-limited incremental exercise test (Bruce protocol) followed within 3 to 14 days by a submaximal, steady-state exercise test performed at 70% of the maximal heart rate achieved during the Bruce protocol. The presence and time of onset of angina and electrocardiographic changes (greater than or equal to 0.1 mV ST-segment depression) as well as oxygen uptake, exercise duration and pressure-rate product were recorded. Thallium-201 (2.5 to 3.0 mCi) was injected during the last minute of exercise during both protocols, and the images were analyzed using both computer-assisted quantitation and visual interpretations. Incremental exercise resulted in anginal symptoms in 84% of patients, and electrocardiographic changes and reversible thallium-201 defects in all patients. In contrast, submaximal exercise produced anginal symptoms in only 26% (p less than 0.01) and electrocardiographic changes in only 47% (p less than 0.05), but resulted in thallium-201 defects in 89% of patients (p = not significant). The locations of the thallium-201 defects, when present, were not different between the 2 exercise protocols. These findings confirm the sequence of the ischemic cascade using 2 levels of exercise and demonstrate that the cascade theory is applicable during varying ischemic intensities in the same patient.

  16. The assessment of dyspnea during the vigorous intensity exercise by three Dyspnea Rating Scales in inactive medical personnel.

    PubMed

    Intarakamhang, Patrawut; Wangjongmeechaikul, Piyathida

    2013-07-24

    It is well recognized that exercise is good for health especially as it's known to prevent metabolic syndromes such as diabetes, hypertension and heart disease. To reap the benefits from exercise the most appropriate level of intensity must be determined, the level of intensity ranging from low, low to moderate to hard (vigorous). This study is aimed to 1. To investigate and evaluate 3 subjective rating scales. The Borg scale, the Combined Numerical Rating Scale (NRS) + FACES Dyspnea Rating Scale (FACES) and the Likert scale, during hard (vigorous) exercise. 2. To compare the effectiveness of the Borg scale and Combined Numerical Rating Scale (NRS) + FACES Dyspnea Rating Scale during the hard (vigorous) intensity exercise. This study uses a descriptive methodology. The sample group was 73 medical personnel that were leading an inactive life style, volunteers from Phramongkutklao Hospital. Participants were randomly divided into 3 groups. Group 1, those to report using the Borg Scale, group 2 using NRS + FACES, and group 3 to subjectively assess the intensity of the exercise using the Likert scale during a treadmill Exercise Stress Test (EST) using the Bruce protocol. The upper limit of the intensity in the study was equal to 85% of the maximal heart rate of all participants. The subjective reporting of the experienced level of dyspnea was undertaken immediately after the completion of exercise. The average age of participants was 23.37 years old. The 26 participants reporting using the Borg scale had mean Borg scale score of 13.46+1.77, a mode score of 15. The 24 participants reporting intensity levels through NRS +FACES had a mean NRS + FACES score of 6.83+1.09 and mode on the NRS + FACES scale equal to 7. The Likert scale group evaluated 23 participants with a mean Likert scale score of 2.74. That is those choosing Levels 2 and 3 were 6 (26.9%) and 17 participants (73.95%), respectively. Comparing the two groups with the Borg scale at equal to or greater than 15

  17. Changes of thioredoxin, oxidative stress markers, inflammation and muscle/renal damage following intensive endurance exercise.

    PubMed

    Sugama, Kaoru; Suzuki, Katsuhiko; Yoshitani, Kayo; Shiraishi, Koso; Miura, Shigeki; Yoshioka, Hiroshi; Mori, Yuichi; Kometani, Takashi

    2015-01-01

    Thioredoxin (TRX) is a 12 kDa protein that is induced by oxidative stress, scavenges reactive oxygen species (ROS) and modulates chemotaxis. Furthermore it is thought to play a protective role in renal ischemia/reperfusion injury. Complement 5a (C5a) is a chemotactic factor of neutrophils and is produced after ischemia/reperfusion injury in the kidney. Both TRX and C5a increase after endurance exercise. Therefore, it may be possible that TRX has an association with C5a in renal disorders and/or renal protection caused by endurance exercise. Accordingly, the aim of this study was to investigate relationships among the changes of urine levels of TRX, C5a and acute kidney injury (AKI) caused by ischemia/reperfusion, inflammatory responses, and oxidative stress following intensive endurance exercise. Also, we applied a newly-developed measurement system of neutrophil migratory activity and ROS-production by use of ex vivo hydrogel methodology with an extracellular matrix to investigate the mechanisms of muscle damage. Fourteen male triathletes participated in a duathlon race consisting of 5 km of running, 40 km of cycling and 5 km of running were recruited to the study. Venous blood and urine samples were collected before, immediately following, 1.5 h and 3 h after the race. Plasma, serum and urine were analyzed using enzyme-linked immunosorbent assays, a free radical analytical system, and the ex vivo neutrophil functional measurement system. These data were analyzed by assigning participants to damaged and minor-damage groups by the presence and absence of renal tubular epithelial cells in the urinary sediments. We found strong associations among urinary TRX, C5a, interleukin (IL)-2, IL-4, IL-8, IL-10, interferon (IFN)-γ and monocyte chemotactic protein (MCP)-1. From the data it might be inferred that urinary TRX, MCP-1 and β-N-acetyl-D-glucosaminidase (NAG) were associated with renal tubular injury. Furthermore, TRX may be influenced by levels of IL-10, regulate

  18. Influence of acute high-intensity aerobic interval exercise bout on selective attention and short-term memory tasks.

    PubMed

    Alves, Christiano R R; Tessaro, Victor H; Teixeira, Luis A C; Murakava, Karina; Roschel, Hamilton; Gualano, Bruno; Takito, Monica Y

    2014-02-01

    Acute moderate intensity continuous aerobic exercise can improve specific cognitive functions, such as short-term memory and selective attention. Moreover, high-intensity interval training (HIT) has been recently proposed as a time-efficient alternative to traditional cardiorespiratory exercise. However, considering previous speculations that the exercise intensity affects cognition in a U-shaped fashion, it was hypothesized that a HIT session may impair cognitive performance. Therefore, this study assessed the effects of an acute HIT session on selective attention and short-term memory tasks. 22 healthy middle-aged individuals (M age = 53.7 yr.) engaged in both (1) a HIT session, 10 1 min. cycling bouts at the intensity corresponding to 80% of the reserve heart rate interspersed by 1 min. active pauses cycling at 60% of the reserve heart rate and (2) a control session, consisting of an active condition with low-intensity active stretching exercise. Before and after each experimental session, cognitive performance was assessed by the Victoria Version of the Stroop test (a selective attention test) and the Digit Span test (a short-term memory test). Following the HIT session, the time to complete the Stroop "Color word" test was significantly lower when compared with that of the control session. The performances in the other subtasks of the Stroop test as well as in the Digit Span test were not significantly different. A HIT session can improve cognitive function.

  19. Effects of treadmill exercise-intensity on short-term memory in the rats born of the lipopolysaccharide-exposed maternal rats.

    PubMed

    Kim, Kijeong; Sung, Yun-Hee; Seo, Jin-Hee; Lee, Sang-Won; Lim, Baek-Vin; Lee, Choong-Yeol; Chung, Yong-Rak

    2015-12-01

    Maternal infection is an important factor causing neonatal brain injury and later developmental disability. In the present study, we investigated the effects of treadmill exercise intensity on short-term memory, hippocampal neurogenesis, and expression of brain-derived neurotrophic factor (BDNF), and tyrosine kinase receptor B (TrkB) in the rats born of lipopolysaccharide (LPS)-exposed maternal rats. The rats were divided into six groups: control group, mild-intensity exercise group, moderate-intensity exercise group, maternal LPS-exposed group, maternal LPS-exposed and mild-intensity exercise group, maternal LPS-exposed and moderate-intensity exercise group. The rats in the exercise groups were forced to run on a treadmill for 30 min 5 times a week for 4 weeks. The exercise load consisted of running at the speed of 8 m/min for the mild-intensity exercise groups and 14 m/min for moderate-intensity exercise groups. The latency in the step-down avoidance task was deter-mined for the short-term memory. Immunohistochemistry for 5-bro-mo-2'-deoxyuridine was performed to determine hippocampal cell proliferation and neurogenesis. Western blot analysis was performed for the detection of BDNF and TrkB expression. In the present study, tread-mill exercise improved short-term memory deteriorated by maternal LPS exposure. Treadmill exercise increased cell proliferation and neurogenesis in the hippocampal dentate gyrus of the rats born of the LPS-exposed maternal rats. Treadmill exercise increased BDNF and TrkB expression in the hippocampus of the rats born of the LPS-exposed maternal rats. These effects of treadmill exercise were similarly appeared at both mild-intensity and moderate-intensity.

  20. Effects of treadmill exercise-intensity on short-term memory in the rats born of the lipopolysaccharide-exposed maternal rats

    PubMed Central

    Kim, Kijeong; Sung, Yun-Hee; Seo, Jin-Hee; Lee, Sang-Won; Lim, Baek-Vin; Lee, Choong-Yeol; Chung, Yong-Rak

    2015-01-01

    Maternal infection is an important factor causing neonatal brain injury and later developmental disability. In the present study, we investigated the effects of treadmill exercise intensity on short-term memory, hippocampal neurogenesis, and expression of brain-derived neurotrophic factor (BDNF), and tyrosine kinase receptor B (TrkB) in the rats born of lipopolysaccharide (LPS)-exposed maternal rats. The rats were divided into six groups: control group, mild-intensity exercise group, moderate-intensity exercise group, maternal LPS-exposed group, maternal LPS-exposed and mild-intensity exercise group, maternal LPS-exposed and moderate-intensity exercise group. The rats in the exercise groups were forced to run on a treadmill for 30 min 5 times a week for 4 weeks. The exercise load consisted of running at the speed of 8 m/min for the mild-intensity exercise groups and 14 m/min for moderate-intensity exercise groups. The latency in the step-down avoidance task was deter-mined for the short-term memory. Immunohistochemistry for 5-bro-mo-2′-deoxyuridine was performed to determine hippocampal cell proliferation and neurogenesis. Western blot analysis was performed for the detection of BDNF and TrkB expression. In the present study, tread-mill exercise improved short-term memory deteriorated by maternal LPS exposure. Treadmill exercise increased cell proliferation and neurogenesis in the hippocampal dentate gyrus of the rats born of the LPS-exposed maternal rats. Treadmill exercise increased BDNF and TrkB expression in the hippocampus of the rats born of the LPS-exposed maternal rats. These effects of treadmill exercise were similarly appeared at both mild-intensity and moderate-intensity. PMID:26730379

  1. Is high-intensity interval training a time-efficient exercise strategy to improve health and fitness?

    PubMed

    Gillen, Jenna B; Gibala, Martin J

    2014-03-01

    Growing research suggests that high-intensity interval training (HIIT) is a time-efficient exercise strategy to improve cardiorespiratory and metabolic health. "All out" HIIT models such as Wingate-type exercise are particularly effective, but this type of training may not be safe, tolerable or practical for many individuals. Recent studies, however, have revealed the potential for other models of HIIT, which may be more feasible but are still time-efficient, to stimulate adaptations similar to more demanding low-volume HIIT models and high-volume endurance-type training. As little as 3 HIIT sessions per week, involving ≤10 min of intense exercise within a time commitment of ≤30 min per session, including warm-up, recovery between intervals and cool down, has been shown to improve aerobic capacity, skeletal muscle oxidative capacity, exercise tolerance and markers of disease risk after only a few weeks in both healthy individuals and people with cardiometabolic disorders. Additional research is warranted, as studies conducted have been relatively short-term, with a limited number of measurements performed on small groups of subjects. However, given that "lack of time" remains one of the most commonly cited barriers to regular exercise participation, low-volume HIIT is a time-efficient exercise strategy that warrants consideration by health practitioners and fitness professionals.

  2. Intensity-level assessment of lower body plyometric exercises based on mechanical output of lower limb joints.

    PubMed

    Sugisaki, Norihide; Okada, Junichi; Kanehisa, Hiroaki

    2013-01-01

    The present study aimed to quantify the intensity of lower extremity plyometric exercises by determining joint mechanical output. Ten men (age, 27.3 ± 4.1 years; height, 173.6 ± 5.4 cm; weight, 69.4 ± 6.0 kg; 1-repetition maximum [1RM] load in back squat 118.5 ± 12.0 kg) performed the following seven plyometric exercises: two-foot ankle hop, repeated squat jump, double-leg hop, depth jumps from 30 and 60 cm, and single-leg and double-leg tuck jumps. Mechanical output variables (torque, angular impulse, power, and work) at the lower limb joints were determined using inverse-dynamics analysis. For all measured variables, ANOVA revealed significant main effects of exercise type for all joints (P < 0.05) along with significant interactions between joint and exercise (P < 0.01), indicating that the influence of exercise type on mechanical output varied among joints. Paired comparisons revealed that there were marked differences in mechanical output at the ankle and hip joints; most of the variables at the ankle joint were greatest for two-foot ankle hop and tuck jumps, while most hip joint variables were greatest for repeated squat jump or double-leg hop. The present results indicate the necessity for determining mechanical output for each joint when evaluating the intensity of plyometric exercises.

  3. Intensity-level assessment of lower body plyometric exercises based on mechanical output of lower limb joints.

    PubMed

    Sugisaki, Norihide; Okada, Junichi; Kanehisa, Hiroaki

    2013-01-01

    The present study aimed to quantify the intensity of lower extremity plyometric exercises by determining joint mechanical output. Ten men (age, 27.3 ± 4.1 years; height, 173.6 ± 5.4 cm; weight, 69.4 ± 6.0 kg; 1-repetition maximum [1RM] load in back squat 118.5 ± 12.0 kg) performed the following seven plyometric exercises: two-foot ankle hop, repeated squat jump, double-leg hop, depth jumps from 30 and 60 cm, and single-leg and double-leg tuck jumps. Mechanical output variables (torque, angular impulse, power, and work) at the lower limb joints were determined using inverse-dynamics analysis. For all measured variables, ANOVA revealed significant main effects of exercise type for all joints (P < 0.05) along with significant interactions between joint and exercise (P < 0.01), indicating that the influence of exercise type on mechanical output varied among joints. Paired comparisons revealed that there were marked differences in mechanical output at the ankle and hip joints; most of the variables at the ankle joint were greatest for two-foot ankle hop and tuck jumps, while most hip joint variables were greatest for repeated squat jump or double-leg hop. The present results indicate the necessity for determining mechanical output for each joint when evaluating the intensity of plyometric exercises. PMID:23327555

  4. Adding sprints to continuous exercise at the intensity that maximises fat oxidation: implications for acute energy balance and enjoyment.

    PubMed

    Crisp, Nicole A; Fournier, Paul A; Licari, Melissa K; Braham, Rebecca; Guelfi, Kym J

    2012-09-01

    The objective was to examine the effect of adding sprints to continuous exercise at the intensity that maximises fat oxidation (Fat(max)) on energy expenditure, substrate oxidation, enjoyment and post-exercise energy intake in boys. Nine overweight and nine normal weight boys (8-12 years) attended the laboratory on three mornings. First, body anthropometrics, peak aerobic capacity and Fat(max) were assessed. On the remaining two sessions, resting metabolic rate was determined before participants completed 30 min of either continuous cycling at Fat(max) (MOD) or sprint interval exercise consisting of continuous cycling at Fat(max) interspersed with four-second maximal sprints every two minutes (SI). Energy expenditure and substrate oxidation were measured during exercise and for 30 min post-exercise, while participants completed a modified Physical Activity Enjoyment Scale (PACES). This was followed by a buffet-like breakfast to measure post-exercise energy intake. Fat oxidation rate was similar between groups and protocols (P>0.05). Both groups expended more energy with SI compared to MOD, resulting from increased carbohydrate oxidation (P<0.05), which was not compensated by increased energy intake. Participants indicated that they preferred SI more than MOD, although there was no significant difference in PACES score between the protocols (P>0.05). In summary, the addition of short sprints to continuous exercise at Fat(max) increased energy expenditure without compromising fat oxidation or stimulating increased post-exercise energy intake. The boys preferred SI and did not perceive it to be any harder than MOD, indicating that sprint interval exercise should be considered in exercise prescription for this population.

  5. Influence of exercise intensity on atrophied quadriceps muscle in the rat

    PubMed Central

    Tanaka, Shoji; Obatake, Taishi; Hoshino, Koichi; Nakagawa, Takao

    2015-01-01

    [Purpose] The aim of this study was to determine the effect of resistance training on atrophied skeletal muscle in rats based on evidence derived from physical therapy. [Subjects and Methods] Rats were forced to undergo squats as resistance training for 3 weeks after atrophying the rectus femoris muscle by hindlimb suspension for 2 weeks. The intensity of resistance training was adjusted to 50% and 70% of the maximum lifted weight, i.e., 50% of the one-repetition maximum and 70% of the one-repetition maximum, respectively. [Results] Three weeks of training did not alter the one-repetition maximum, and muscle fibers were injured while measuring the one-repetition maximum and reloading. The decrease in cross-sectional area in the rectus femoris muscle induced by unloading for 2 weeks was significantly recovered after training at 70% of the one-repetition maximum. The levels of muscle RING-finger protein-1 mRNA expression were significantly lower in muscles trained at 70% of the one-repetition maximum than in untrained muscles. [Conclusion] These results suggest that high-intensity resistance training can promote atrophic muscle recovery, which provides a scientific basis for therapeutic exercise methods for treatment of atrophic muscle in physical therapy. PMID:26696716

  6. [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).

  7. High-intensity physical exercise disrupts implicit memory in mice: involvement of the striatal glutathione antioxidant system and intracellular signaling.

    PubMed

    Aguiar, A S; Boemer, G; Rial, D; Cordova, F M; Mancini, G; Walz, R; de Bem, A F; Latini, A; Leal, R B; Pinho, R A; Prediger, R D S

    2010-12-29

    Physical exercise is a widely accepted behavioral strategy to enhance overall health, including mental function. However, there is controversial evidence showing brain mitochondrial dysfunction, oxidative damage and decreased neurotrophin levels after high-intensity exercise, which presumably worsens cognitive performance. Here we investigated learning and memory performance dependent on different brain regions, glutathione antioxidant system, and extracellular signal-regulated protein kinase 1/2 (ERK1/2), serine/threonine protein kinase (AKT), cAMP response element binding (CREB) and dopamine- and cyclic AMP-regulated phosphoprotein (DARPP)-32 signaling in adult Swiss mice submitted to 9 weeks of high-intensity exercise. The exercise did not alter the animals' performance in the reference and working memory versions of the water maze task. On the other hand, we observed a significant impairment in the procedural memory (an implicit memory that depends on basal ganglia) accompanied by a reduced antioxidant capacity and ERK1/2 and CREB signaling in this region. In addition, we found increased striatal DARPP-32-Thr-75 phosphorylation in trained mice. These findings indicate an increased vulnerability of the striatum to high-intensity exercise associated with the disruption of implicit memory in mice and accompanied by alteration of signaling proteins involved in the plasticity of this brain structure.

  8. Effects of anabolic steroids and high-intensity aerobic exercise on skeletal muscle of transgenic mice.

    PubMed

    Fontana, Karina; Campos, Gerson E R; Staron, Robert S; da Cruz-Höfling, Maria Alice

    2013-01-01

    In an attempt to shorten recovery time and improve performance, strength and endurance athletes occasionally turn to the illicit use of anabolic-androgenic steroids (AAS). This study evaluated the effects of AAS treatment on the muscle mass and phenotypic characteristics of transgenic mice subjected to a high-intensity, aerobic training program (5d/wk for 6 weeks). The transgenic mice (CETP(+/-)LDLr(-/+)) were engineered to exhibit a lipid profile closer to humans. Animals were divided into groups of sedentary (Sed) and/or training (Ex) mice (each treated orally with AAS or gum arabic/vehicle: Sed-C, Sed-M, ex-C, ex-M). The effects of AAS (mesterolone: M) on specific phenotypic adaptations (muscle wet weight, cross-sectional area, and fiber type composition) in three hindlimb muscles (soleus:SOL, tibialis anterior:TA and gastrocnemius:GAS) were assessed. In order to detect subtle changes in fiber type profile, the entire range of fiber types (I, IC, IIAC, IIA, IIAD, IID, IIDB, IIB) was delineated using mATPase histochemistry. Body weight gain occurred throughout the study for all groups. However, the body weight gain was significantly minimized with exercise. This effect was blunted with mesterolone treatment. Both AAS treatment (Sed-M) and high-intensity, aerobic training (ex-C) increased the wet weights of all three muscles and induced differential hypertrophy of pure and hybrid fibers. Combination of AAS and training (ex-M) resulted in enhanced hypertrophy. In the SOL, mesterolone treatment (Sed-M and ex-M) caused dramatic increases in the percentages of fiber types IC, IIAC, IIAD, IID, with concomitant decrease in IIA, but had minimal impact on fiber type percentages in the predominantly fast muscles. Overall, the AAS-induced differential adaptive changes amounted to significant fiber type transformations in the fast-to-slow direction in SOL. AAS treatment had a significant effect on muscle weights and fiber type composition in SOL, TA and GAS which was even

  9. Randomized trial comparing exercise therapy, alternating cold and hot therapy, and low intensity laser therapy for chronic lumbar muscle strain

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoguang; Li, Jie; Liu, Timon Chengyi; Yuan, Jianqin; Luo, Qingming

    2008-12-01

    The purpose of this study was to compare the effects of exercise therapy, alternating cold and hot (ACH) therapy and low intensity laser (LIL) therapy in patients with chronic lumbar muscle strain (CLMS). Thirty-two patients were randomly allocated to four groups: exercise group, ACH group, LIL group, and combination group of exercise, ACH and LIL, eight in each group. Sixteen treatments were given over the course of 4 weeks. Lumbar muscle endurance, flexion and lateral flexion measures, visual analogue scale (VAS) and lumbar disability questionnaire (LDQ) were used in the clinical and functional evaluations before, immediately after, and 4 weeks after treatment. It was found that the values of endurance, VAS and LDQ in all groups were significantly improved from before to after treatment (P < 0.01). The combination group showed significantly larger reduction on pain level and functional disability than the other groups immediately and 4 weeks after treatment (P < 0.01). Pain level reduced significantly more in the ACH group than in the exercise group or the LIL group immediately and 4 weeks after treatment (P < 0.05). Lumbar muscle endurance and spinal ranges of motion in all groups were improved after treatment but there was no significant difference between any therapy groups. In conclusion, exercise therapy, ACH therapy and LIL therapy were effective in the treatment of CLMS. ACH therapy was more effective than exercise therapy or LIL therapy. The combination therapy of exercise, ACH and LIL had still better rehabilitative effects on CLMS.

  10. Effects of aerobic exercise intensity on 24-h ambulatory blood pressure in individuals with type 2 diabetes and prehypertension

    PubMed Central

    Karoline de Morais, Pâmella; Sales, Marcelo Magalhães; Alves de Almeida, Jeeser; Motta-Santos, Daisy; Victor de Sousa, Caio; Simões, Herbert Gustavo

    2015-01-01

    [Purpose] To verify the effects of different intensities of aerobic exercise on 24-hour ambulatory blood pressure (BP) responses in individuals with type 2 diabetes mellitus (T2D) and prehypertension. [Subjects and Methods] Ten individuals with T2D and prehypertension (55.8 ± 7.7 years old; blood glucose 133.0 ± 36.7 mg·dL−1 and awake BP 130.6 ± 1.6/ 80.5 ± 1.8 mmHg) completed three randomly assigned experiments: non-exercise control (CON) and exercise at moderate (MOD) and maximal (MAX) intensities. Heart rate (HR), BP, blood lactate concentrations ([Lac]), oxygen uptake (VO2), and rate of perceived exertion (RPE) were measured at rest, during the experimental sessions, and during the 60 min recovery period. After this period, ambulatory blood pressure was monitored for 24 h. [Results] The results indicate that [Lac] (MAX: 6.7±2.0 vs. MOD: 3.8±1.2 mM), RPE (MAX: 19±1.3 vs. MOD: 11±2.3) and VO2peak (MAX: 20.2±4.1 vs. MOD: 14.0±3.0 mL·kg−1·min−1) were highest following the MAX session. Compared with CON, only MAX elicited post-exercise BP reduction that lasted for 8 h after exercise and during sleep. [Conclusion] A single session of aerobic exercise resulted in 24 h BP reductions in individuals with T2D, especially while sleeping, and this reduction seems to be dependent on the intensity of the exercise performed. PMID:25642036

  11. Comparison of responses to two high-intensity intermittent exercise protocols.

    PubMed

    Gist, Nicholas H; Freese, Eric C; Cureton, Kirk J

    2014-11-01

    The purpose of this study was to compare peak cardiorespiratory, metabolic, and perceptual responses to acute bouts of sprint interval cycling (SIC) and a high-intensity intermittent calisthenics (HIC) protocol consisting of modified "burpees." Eleven (8 men and 3 women) moderately trained, college-aged participants (age = 21.9 ± 2.1, body mass index = 24.8 ± 1.9, V[Combining Dot Above]O2peak = 54.1 ± 5.4 ml·kg·min) completed 4 testing sessions across 9 days with each session separated by 48-72 hours. Using a protocol of 4 repeated bouts of 30-second "all-out" efforts interspersed with 4-minute active recovery periods, responses to SIC and HIC were classified relative to peak values. Mean values for %V[Combining Dot Above]O2peak and %HRpeak for SIC (80.4 ± 5.3% and 86.8 ± 3.9%) and HIC (77.6 ± 6.9% and 84.6 ± 5.3%) were not significantly different (p > 0.05). Effect sizes (95% confidence interval) calculated for mean differences were: %V[Combining Dot Above]O2peak Cohen's d = 0.51 (0.48-0.53) and %HRpeak Cohen's d = 0.57 (0.55-0.59). A low-volume, high-intensity bout of repeated whole-body calisthenic exercise induced cardiovascular responses that were not significantly different but were ∼1/2SD lower than "all-out" SIC. These results suggest that in addition to the benefit of reduced time commitment, a high-intensity interval protocol of calisthenics elicits vigorous cardiorespiratory and perceptual responses and may confer physiological adaptations and performance improvements similar to those reported for SIC. The potential efficacy of this alternative interval training method provides support for its application by athletes, coaches, and strength and conditioning professionals.

  12. An attempt to determine the absolute geomagnetic field intensity in Southwestern Iceland during the Gauss-Matuyama reversal

    NASA Astrophysics Data System (ADS)

    Goguitchaichvili, Avto; Prévot, Michel; Thompson, John; Roberts, Neil

    1999-08-01

    We have measured the variation in the intensity of the geomagnetic field during the Gauss-Matuyama (N4-R3) polarity reversal by application of the Thelliers' method to specimens of lava flows from Hvalfjördur district in Western Iceland (Reynivallahals Mts.). Eleven lava flows all show very similar directions corresponding to an equatorial VGP (Plat=2.9°N, Plong=81.9°E, A95=4.2, K=119). Twenty-nine specimens from nine of the flows were pre-selected for palaeointensity determination on the basis that specimens from the same drill cores showed a single component of magnetisation upon thermal or AF demagnetisation, and possessed low magnetic viscosity and reversible susceptibility curves upon heating at 600-650°C. Observation that the directional data obtained in the course of the palaeointensity experiments occasionally showed substantial non-linearity indicates that a significant chemical remanent magnetization (CRM) can be acquired in the direction of the laboratory field during heating at T. For each double heating step we calculated the ratio of CRM( T) to the magnitude of the natural remanent magnetization (NRM( T)) in the direction of characteristic remanence (obtained independently from another specimen from the same core). When this ratio exceeded 15%, the paleointensity data was rejected. In addition, specimens for which the quality factor was less than 5 were rejected. Twelve reliable palaeointensity values were obtained from specimens representing five lava flows. The results confirm that the palaeointensity was substantially reduced during the N4-R3 reversal. The range of mean palaeointensity values obtained for the five flows is 8.8 to 20.5 and the overall mean is 14.8±4.6 μT. This corresponds to an equivalent VDM of 3.81±1.19 (10 22 A m 2). A comparison of all Thellier palaeointensity data from the R3 magnetozone in the Rayinivallahals Mts. area reveals a progressive although irregular increase in the palaeointensity between the Gauss

  13. High-Intensity Resistance Exercise Promotes Postexercise Hypotension Greater than Moderate Intensity and Affects Cardiac Autonomic Responses in Women Who Are Hypertensive.

    PubMed

    de Freitas Brito, Aline; Brasileiro-Santos, Maria do S; Coutinho de Oliveira, Caio V; Sarmento da Nóbrega, Thereza K; Lúcia de Moraes Forjaz, Cláudia; da Cruz Santos, Amilton

    2015-12-01

    The purpose of this study was to evaluate the effect of high-intensity resistance exercise (RE) sessions on blood pressure (BP), heart rate (HR), cardiac autonomic modulation, and forearm blood flow (FBF). Sixteen trained hypertensive women (n = 16, 56 ± 3 years) completed the following 3 experimental sessions: control (CS), RE at 50% (EX50%), and RE at 80% (EX80%) of 1 repetition maximum (1RM). Both EX50% and EX80% comprised a set of 10 repetitions of 10 exercises, with an interval of 90 seconds between exercises. Measurements were taken preintervention and postintervention (at 10, 30, 50, 70, and 90 minutes of recovery). Reductions in systolic/diastolic BP after exercise were greater in EX80% (largest declines, -29 ± 4/-14 ± 5 mm Hg) than EX50% (largest declines, -18 ± 6/-8 ± 5 mm Hg, p ≤ 0.05). Heart rate and cardiac sympathovagal balance (LF/HF) increased more in relation to pre-exercise values in EX80% than EX50% (largest increases 96 ± 3 vs. 90 ± 4 b·min, LF/HF = 1.77 ± 0.25 vs. 1.40 ± 0.20, respectively, p ≤ 0.05). Increases in FBF and hyperemia was also higher in EX80% than EX50% compared with pre-exercise (4.97 ± 0.28 vs. 4.36 ± 0.27 ml·min·100 ml and 5.90 ± 0.20 vs. 5.38 ± 0.25 ml·min·100 ml; p ≤ 0.05, respectively). These results suggest that RE of higher intensity promoted greater postexercise hypotension accompanied by greater increases in FBF, vasodilator response, HR, and cardiac sympathovagal balance. PMID:25992658

  14. Influence of exercise intensity and joint angle on endurance time prediction of sustained submaximal isometric knee extensions.

    PubMed

    Boyas, Sébastien; Guével, Arnaud

    2011-06-01

    The purpose of endurance time (T (lim)) prediction is to determine the exertion time of a muscle contraction before it occurs. T (lim) prediction would then allow the evaluation of muscle capacities limiting fatigue and deleterious effects associated with exhaustive exercises. The present study aimed to analyze the influence of exercise intensity and joint angle on T (lim) prediction using changes in surface electromyographic (sEMG) signals recorded during the first moments of the exercise. Fifteen male performed four knee extensions sustained until exhaustion that were different in exercise intensity (20% or 50% of maximal voluntary torque-MVT) and in joint angle (40 or 70º, 0° = full extension). T (lim) prediction was explored using some parameters of the sEMG signals from rectus femoris, vastus medialis and vastus lateralis muscles. Changes in sEMG parameters (root mean square, mean power frequency and frequency banding 6-30 Hz) were expressed using the slope of the linear regression and the area ratio index. Results indicated that relationships between changes in sEMG signal and T (lim) (0.51 < r < 0.83) were greater for experimental conditions associated with higher exercise intensity (50% MVT) and so to lower time duration. Knee joint angle had little influence on T (lim) prediction results. Results also showed higher T (lim) prediction considering spectral parameters and area ratio. This could be in relation to differences in relative contribution of central and peripheral fatigue that seems to change according to the exercise intensity, but also to the influence of psychological factors that increases with the duration of the task.

  15. Recovery facilitation with Montmorency cherries following high-intensity, metabolically challenging exercise.

    PubMed

    Bell, Phillip G; Walshe, Ian H; Davison, Gareth W; Stevenson, Emma J; Howatson, Glyn

    2015-04-01

    The impact of Montmorency tart cherry (Prunus cerasus L.) concentrate (MC) on physiological indices and functional performance was examined following a bout of high-intensity stochastic cycling. Trained cyclists (n = 16) were equally divided into 2 groups (MC or isoenergetic placebo (PLA)) and consumed 30 mL of supplement, twice per day for 8 consecutive days. On the fifth day of supplementation, participants completed a 109-min cycling trial designed to replicate road race demands. Functional performance (maximum voluntary isometric contraction (MVIC), cycling efficiency, 6-s peak cycling power) and delayed onset muscle soreness were assessed at baseline, 24, 48, and 72 h post-trial. Blood samples collected at baseline, immediately pre- and post-trial, and at 1, 3, 5, 24, 48, and 72 h post-trial were analysed for indices of inflammation (interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor alpha, high-sensitivity C-reactive protein (hsCRP)), oxidative stress (lipid hydroperoxides), and muscle damage (creatine kinase). MVIC (P < 0.05) did not decline in the MC group (vs. PLA) across the 72-h post-trial period and economy (P < 0.05) was improved in the MC group at 24 h. IL-6 (P < 0.001) and hsCRP (P < 0.05) responses to the trial were attenuated with MC (vs. PLA). No other blood markers were significantly different between MC and PLA groups. The results of the study suggest that Montmorency cherry concentrate can be an efficacious functional food for accelerating recovery and reducing exercise-induced inflammation following strenuous cycling exercise. PMID:25794236

  16. High intensity exercise affects diurnal variation of some biological markers in trained subjects.

    PubMed

    Hammouda, O; Chtourou, H; Chahed, H; Ferchichi, S; Chaouachi, A; Kallel, C; Miled, A; Chamari, K; Souissi, N

    2012-11-01

    The study investigated if markers of muscle injury and antioxidant status were affected by a Wingate test performed at 2 different times of day. 15 young male footballers performed 2 tests (randomized) at 07:00-h and 17:00-h. Fasting blood samples were collected before and 3 min after each test for assessment of markers of muscle injury and antioxidant status. Resting oral temperature was recorded during each session. Peak power (10.76 ± 1.05 vs. 11.15 ± 0.83 W.kg( - 1)) and fatigue index (0.41 ± 0.04 vs. 0.49 ± 0.13%) during the Wingate test, and core temperature, were significantly higher (all p<0.05) in the evening. Markers of muscle injury were significantly higher in the evening before and after exercise (e. g., 148.7 ± 67.05 vs. 195 ± 74.6 and 191.6 ± 79.52 vs. 263.6 ± 96.06 IU.L (- 1), respectively, for creatine kinase; both p<0.001). Antioxidant parameters increased after the Wingate test but only resting values were significantly higher in the morning (e. g., 1.33 ± 0.19 vs. 1.19 ± 0.14 µmol.L (- 1) for total antioxidant status; p<0.05). The results indicate that muscle injury and antioxidant activity after the Wingate test were higher in the evening, suggesting a possible link between the biochemical measures and the diurnal fluctuation of anaerobic performance. However, repetition of this study after prescribed rather than self-selected exercise intensity is recommended. PMID:22791622

  17. Recovery facilitation with Montmorency cherries following high-intensity, metabolically challenging exercise.

    PubMed

    Bell, Phillip G; Walshe, Ian H; Davison, Gareth W; Stevenson, Emma J; Howatson, Glyn

    2015-04-01

    The impact of Montmorency tart cherry (Prunus cerasus L.) concentrate (MC) on physiological indices and functional performance was examined following a bout of high-intensity stochastic cycling. Trained cyclists (n = 16) were equally divided into 2 groups (MC or isoenergetic placebo (PLA)) and consumed 30 mL of supplement, twice per day for 8 consecutive days. On the fifth day of supplementation, participants completed a 109-min cycling trial designed to replicate road race demands. Functional performance (maximum voluntary isometric contraction (MVIC), cycling efficiency, 6-s peak cycling power) and delayed onset muscle soreness were assessed at baseline, 24, 48, and 72 h post-trial. Blood samples collected at baseline, immediately pre- and post-trial, and at 1, 3, 5, 24, 48, and 72 h post-trial were analysed for indices of inflammation (interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor alpha, high-sensitivity C-reactive protein (hsCRP)), oxidative stress (lipid hydroperoxides), and muscle damage (creatine kinase). MVIC (P < 0.05) did not decline in the MC group (vs. PLA) across the 72-h post-trial period and economy (P < 0.05) was improved in the MC group at 24 h. IL-6 (P < 0.001) and hsCRP (P < 0.05) responses to the trial were attenuated with MC (vs. PLA). No other blood markers were significantly different between MC and PLA groups. The results of the study suggest that Montmorency cherry concentrate can be an efficacious functional food for accelerating recovery and reducing exercise-induced inflammation following strenuous cycling exercise.

  18. Evaluating a Nationwide Recreational Football Intervention: Recruitment, Attendance, Adherence, Exercise Intensity, and Health Effects.

    PubMed

    Fløtum, Liljan Av; Ottesen, Laila S; Krustrup, Peter; Mohr, Magni

    2016-01-01

    The present study evaluated a nationwide exercise intervention with Football Fitness in a small-scale society. In all, 741 adult participants (20-72 yrs) were successfully recruited for Football Fitness training in local football clubs, corresponding to 2.1% of the adult population. A preintervention test battery including resting heart rate (RHR), blood pressure, and body mass measurements along with performance tests (Yo-Yo Intermittent Endurance level 1 (Yo-Yo IE1), the Arrowhead Agility Test, and the Flamingo Balance Test) were performed (n = 502). Training attendance (n = 310) was 1.6 ± 0.2 sessions per week (range: 0.6-2.9), corresponding to 28.8 ± 1.0 sessions during the 18 wk intervention period. After 18 wks mean arterial pressure (MAP) was -2.7 ± 0.7 mmHg lower (P < 0.05; n = 151) with even greater (P < 0.05) reductions for those with baseline MAP values >99 mmHg (-5.6 ± 1.5 mmHg; n = 50). RHR was lowered (P < 0.05) by 6 bpm after intervention (77 ± 1 to 71 ± 1 bpm). Yo-Yo IE1 performance increased by 41% (540 ± 27 to 752 ± 45 m), while agility and postural balance were improved (P < 0.05) by ~6 and ~45%, respectively. In conclusion, Football Fitness was shown to be a successful health-promoting nationwide training intervention for adult participants with an extraordinary recruitment, a high attendance rate, moderate adherence, high exercise intensity, and marked benefits in cardiovascular health profile and fitness. PMID:27437401

  19. Evaluating a Nationwide Recreational Football Intervention: Recruitment, Attendance, Adherence, Exercise Intensity, and Health Effects

    PubMed Central

    Fløtum, Liljan av; Ottesen, Laila S.; Krustrup, Peter

    2016-01-01

    The present study evaluated a nationwide exercise intervention with Football Fitness in a small-scale society. In all, 741 adult participants (20–72 yrs) were successfully recruited for Football Fitness training in local football clubs, corresponding to 2.1% of the adult population. A preintervention test battery including resting heart rate (RHR), blood pressure, and body mass measurements along with performance tests (Yo-Yo Intermittent Endurance level 1 (Yo-Yo IE1), the Arrowhead Agility Test, and the Flamingo Balance Test) were performed (n = 502). Training attendance (n = 310) was 1.6 ± 0.2 sessions per week (range: 0.6–2.9), corresponding to 28.8 ± 1.0 sessions during the 18 wk intervention period. After 18 wks mean arterial pressure (MAP) was −2.7 ± 0.7 mmHg lower (P < 0.05; n = 151) with even greater (P < 0.05) reductions for those with baseline MAP values >99 mmHg (−5.6 ± 1.5 mmHg; n = 50). RHR was lowered (P < 0.05) by 6 bpm after intervention (77 ± 1 to 71 ± 1 bpm). Yo-Yo IE1 performance increased by 41% (540 ± 27 to 752 ± 45 m), while agility and postural balance were improved (P < 0.05) by ~6 and ~45%, respectively. In conclusion, Football Fitness was shown to be a successful health-promoting nationwide training intervention for adult participants with an extraordinary recruitment, a high attendance rate, moderate adherence, high exercise intensity, and marked benefits in cardiovascular health profile and fitness. PMID:27437401

  20. Plasma cytokine and exertional responses in relation to exercise intensity and volume of exercising muscle mass during arm-crank ergometry.

    PubMed

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

    2015-08-01

    This original study investigated the effect of submaximal exercise intensity and volume of contracting muscle mass on plasma inflammation-mediating cytokine and perceived exertional responses to acute arm-crank ergometry (ACE). Twelve recreationally active but upper limb untrained males performed 30 min of (i) low-intensity (40% peak oxygen uptake) ACE (LOW); (ii) moderate-intensity (60% peak oxygen uptake) ACE (MOD); and (iii) concurrent low-intensity (40% peak oxygen uptake) ACE plus lower limb cycle ergometry to match total power output in MOD (HYB). Plasma concentrations of interleukin (IL)-6, IL-10, IL-1ra, adrenaline, and cortisol were determined at rest, immediately postexercise, and 1 h and 2 h postexercise. Heart rate (HR) and differentiated ratings of perceived exertion (RPE) were also recorded. Plasma IL-6 concentrations were elevated (p < 0.05) immediately postexercise and 1 h postexercise (∼ 2.5-fold) in all trials and 2 h postexercise in MOD (3-fold). Plasma IL-1ra concentrations were elevated (p < 0.05) 2 h postexercise in MOD only (2-fold). No plasma IL-10, cortisol, and adrenaline responses were observed. HR and differentiated RPE were significantly higher during MOD than HYB and LOW. Peripheral RPE were significantly higher than central and overall RPE in each trial. Thirty minutes of moderate intensity ACE initiated a plasma cytokine response associated with the protective effect of regular exercise against cardiovascular and metabolic disease risk. Further work is required to establish an optimal intensity and duration of upper limb exercise to maximise the anti-inflammatory potential whilst managing the risk of over-use injury.

  1. Supplemental vitamin D enhances the recovery in peak isometric force shortly after intense exercise

    PubMed Central

    2013-01-01

    that supplemental vitamin D may serve as an attractive complementary approach to enhance the recovery of skeletal muscle strength following intense exercise in reportedly active adults with a sufficient vitamin D status prior to supplementation. PMID:24313936

  2. Yerba Maté (Illex Paraguariensis) ingestion augments fat oxidation and energy expenditure during exercise at various submaximal intensities

    PubMed Central

    2014-01-01

    Background Ingesting Yerba Maté (YM) has become widely popular for health promotion, obesity prevention and body weight reduction, primarily due its thermogenic effectiveness. However, the YM effects on fat metabolism during exercise, when fat metabolism is already increased several fold, are unknown. The present study investigated whether acute YM ingestion augments fat metabolism parameters of fatty acid oxidation (FAO) and energy expenditure derived from FAO (EEFAO) during exercise with several intensities. Methods Fourteen healthy males and females were randomised in a repeated measures crossover experimental design. All participants ingested either 1000 mg of YM or placebo capsules (PLC) 60 min before performing two incremental exercise ergometry tests. Power output was initiated at and increased by 0.5 W.kg-1 of body weight every 3 min stage, until reaching peak oxygen uptake V˙O2Peak. Expired gases and stoichiometric indirect calorimetry were used to analyse FAO and EEFAO. Capillary blood samples were collected and analysed for blood lactate concentration (BLC) at rest and at each submaximal and maximal power output. Results YM significantly increased FAO and EEFAO by 24% in all submaximal exercise intensities below 70% of V˙O2peak (p < 0.001, ANOVA main effects) with post hoc tests showing a higher FAO and EEFAO (p < 0.05) at the lower exercise intensities (e.g. 0.26 ± 0.09 vs. 0.35 ± 0.10 and 0.25 ± 0.12 vs. 0.33 ± 0.11 g.min-1 at 40 and 50% of V˙O2peak respectively). These changes were combined with a trend towards a decrease in BLC (P = 0.066), and without a significant difference in V˙O2peak, peak power, peak RER, or peak BLC. Conclusions Acute YM ingestion augments the exercise dependent increase in FAO and EEFAO at submaximal exercise intensities without negatively affecting maximal exercise performance, suggesting a potential role for YM ingestion to increase the exercise effectiveness for weight loss and

  3. Open-ended time durations for stationary start intense cycle ergometer exercise testing.

    PubMed

    Klopp, Dawn Marie; Vargas, Nicole Theresa; Robergs, Robert Andrew

    2013-05-01

    The study involved application of different applied loads to measure altered test durations, time to peak power, peak power, and peak cadence during intense cycle ergometry exercise. Healthy, physically active male (n = 11) and female (n = 11) subjects (18-45 years) performed the following 3 bouts of intense cycle ergometry at peak cadence to volitional exhaustion on 3 separate days, 48 h to 1 week apart: (i) 85 g·kg(-1) body mass load; (ii) 75 g·kg(-1) body mass load; and (iii) 100 g·kg(-1) body mass load. Trials (ii) and (iii) were performed in random order after trial (i). Exercise consisted of a stationary start, where test termination occurred when cadence decreased to <35 r·min(-1). Mean (±SD) for gender main effects for time to peak power were 7.64 ± 2.76 vs. 9.49 ± 2.76 s (p < 0.001) for males and females, respectively. Relative peak power data for males vs. females for 75, 85, and 100 g·kg(-1) were 10.01 ± 1.371 vs. 7.81 ± 1.25, 10.16 ± 1.61 vs. 7.67 ± 1.35, and 10.91 ± 2.03 vs. 7.31 ± 1.37 W·kg(-1), respectively. The means for test duration for the GENDER × LOAD interaction (p = 0.09) were 68.25 ± 17.80 vs. 56.5 ± 11.56, 63.70 ± 17.21 vs.57.95 ± 10.45, and 51.99 ± 14.59 vs. 49.54 ± 12.45 s for males vs. females for each of 75, 85, and 100 g·kg(-1), respectively. Stepwise multiple regression involving load and gender resulted in an explanation of variance (R(2)) of only 31.2%. Open-ended testing should be performed at a load of 100 g·kg(-1) body mass for males and 85 g·kg(-1) body mass females, causing volitional exhaustion in approximately 60 s and should allow test duration to be another measured variable.

  4. Intensity-dependent alterations in the excitability of cortical and spinal projections to the knee extensors during isometric and locomotor exercise

    PubMed Central

    Weavil, J. C.; Sidhu, S. K.; Mangum, T. S.; Richardson, R. S.

    2015-01-01

    We investigated the role of exercise intensity and associated central motor drive in determining corticomotoneuronal excitability. Ten participants performed a series of nonfatiguing (3 s) isometric single-leg knee extensions (ISO; 10–100% of maximal voluntary contractions, MVC) and cycling bouts (30–160% peak aerobic capacity, Wpeak). At various exercise intensities, electrical potentials were evoked in the vastus lateralis (VL) and rectus femoris (RF) via transcranial magnetic stimulation (motor-evoked potentials, MEP), and electrical stimulation of both the cervicomedullary junction (cervicomedullary evoked potentials, CMEP) and the femoral nerve (maximal M-waves, Mmax). Whereas Mmax remained unchanged in both muscles (P > 0.40), voluntary electromyographic activity (EMG) increased in an exercise intensity-dependent manner for ISO and cycling exercise in VL and RF (both P < 0.001). During ISO exercise, MEPs and CMEPs progressively increased in VL and RF until a plateau was reached at ∼75% MVC; further increases in contraction intensity did not cause additional changes (P > 0.35). During cycling exercise, VL-MEPs and CMEPs progressively increased by ∼65% until a plateau was reached at Wpeak. In contrast, RF MEPs and CMEPs progressively increased by ∼110% throughout the tested cycling intensities without the occurrence of a plateau. Furthermore, alterations in EMG below the plateau influenced corticomotoneuronal excitability similarly between exercise modalities. In both exercise modalities, the MEP-to-CMEP ratio did not change with exercise intensity (P > 0.22). In conclusion, increases in exercise intensity and EMG facilitates the corticomotoneuronal pathway similarly in isometric knee extension and locomotor exercise until a plateau occurs at a submaximal exercise intensity. This facilitation appears to be primarily mediated by increases in excitability of the motoneuron pool. PMID:25876651

  5. Intensity-dependent alterations in the excitability of cortical and spinal projections to the knee extensors during isometric and locomotor exercise.

    PubMed

    Weavil, J C; Sidhu, S K; Mangum, T S; Richardson, R S; Amann, M

    2015-06-15

    We investigated the role of exercise intensity and associated central motor drive in determining corticomotoneuronal excitability. Ten participants performed a series of nonfatiguing (3 s) isometric single-leg knee extensions (ISO; 10-100% of maximal voluntary contractions, MVC) and cycling bouts (30-160% peak aerobic capacity, W peak). At various exercise intensities, electrical potentials were evoked in the vastus lateralis (VL) and rectus femoris (RF) via transcranial magnetic stimulation (motor-evoked potentials, MEP), and electrical stimulation of both the cervicomedullary junction (cervicomedullary evoked potentials, CMEP) and the femoral nerve (maximal M-waves, M max). Whereas M max remained unchanged in both muscles (P > 0.40), voluntary electromyographic activity (EMG) increased in an exercise intensity-dependent manner for ISO and cycling exercise in VL and RF (both P < 0.001). During ISO exercise, MEPs and CMEPs progressively increased in VL and RF until a plateau was reached at ∼ 75% MVC; further increases in contraction intensity did not cause additional changes (P > 0.35). During cycling exercise, VL-MEPs and CMEPs progressively increased by ∼ 65% until a plateau was reached at W peak. In contrast, RF MEPs and CMEPs progressively increased by ∼ 110% throughout the tested cycling intensities without the occurrence of a plateau. Furthermore, alterations in EMG below the plateau influenced corticomotoneuronal excitability similarly between exercise modalities. In both exercise modalities, the MEP-to-CMEP ratio did not change with exercise intensity (P > 0.22). In conclusion, increases in exercise intensity and EMG facilitates the corticomotoneuronal pathway similarly in isometric knee extension and locomotor exercise until a plateau occurs at a submaximal exercise intensity. This facilitation appears to be primarily mediated by increases in excitability of the motoneuron pool. PMID:25876651

  6. Complex network models reveal correlations among network metrics, exercise intensity and role of body changes in the fatigue process.

    PubMed

    Pereira, Vanessa Helena; Gama, Maria Carolina Traina; Sousa, Filipe Antônio Barros; Lewis, Theodore Gyle; Gobatto, Claudio Alexandre; Manchado-Gobatto, Fúlvia Barros

    2015-05-21

    The aims of the present study were analyze the fatigue process at distinct intensity efforts and to investigate its occurrence as interactions at distinct body changes during exercise, using complex network models. For this, participants were submitted to four different running intensities until exhaustion, accomplished in a non-motorized treadmill using a tethered system. The intensities were selected according to critical power model. Mechanical (force, peak power, mean power, velocity and work) and physiological related parameters (heart rate, blood lactate, time until peak blood lactate concentration (lactate time), lean mass, anaerobic and aerobic capacities) and IPAQ score were obtained during exercises and it was used to construction of four complex network models. Such models have both, theoretical and mathematical value, and enables us to perceive new insights that go beyond conventional analysis. From these, we ranked the influences of each node at the fatigue process. Our results shows that nodes, links and network metrics are sensibility according to increase of efforts intensities, been the velocity a key factor to exercise maintenance at models/intensities 1 and 2 (higher time efforts) and force and power at models 3 and 4, highlighting mechanical variables in the exhaustion occurrence and even training prescription applications.

  7. Complex network models reveal correlations among network metrics, exercise intensity and role of body changes in the fatigue process

    NASA Astrophysics Data System (ADS)

    Pereira, Vanessa Helena; Gama, Maria Carolina Traina; Sousa, Filipe Antônio Barros; Lewis, Theodore Gyle; Gobatto, Claudio Alexandre; Manchado-Gobatto, Fúlvia Barros

    2015-05-01

    The aims of the present study were analyze the fatigue process at distinct intensity efforts and to investigate its occurrence as interactions at distinct body changes during exercise, using complex network models. For this, participants were submitted to four different running intensities until exhaustion, accomplished in a non-motorized treadmill using a tethered system. The intensities were selected according to critical power model. Mechanical (force, peak power, mean power, velocity and work) and physiological related parameters (heart rate, blood lactate, time until peak blood lactate concentration (lactate time), lean mass, anaerobic and aerobic capacities) and IPAQ score were obtained during exercises and it was used to construction of four complex network models. Such models have both, theoretical and mathematical value, and enables us to perceive new insights that go beyond conventional analysis. From these, we ranked the influences of each node at the fatigue process. Our results shows that nodes, links and network metrics are sensibility according to increase of efforts intensities, been the velocity a key factor to exercise maintenance at models/intensities 1 and 2 (higher time efforts) and force and power at models 3 and 4, highlighting mechanical variables in the exhaustion occurrence and even training prescription applications.

  8. Complex network models reveal correlations among network metrics, exercise intensity and role of body changes in the fatigue process.

    PubMed

    Pereira, Vanessa Helena; Gama, Maria Carolina Traina; Sousa, Filipe Antônio Barros; Lewis, Theodore Gyle; Gobatto, Claudio Alexandre; Manchado-Gobatto, Fúlvia Barros

    2015-01-01

    The aims of the present study were analyze the fatigue process at distinct intensity efforts and to investigate its occurrence as interactions at distinct body changes during exercise, using complex network models. For this, participants were submitted to four different running intensities until exhaustion, accomplished in a non-motorized treadmill using a tethered system. The intensities were selected according to critical power model. Mechanical (force, peak power, mean power, velocity and work) and physiological related parameters (heart rate, blood lactate, time until peak blood lactate concentration (lactate time), lean mass, anaerobic and aerobic capacities) and IPAQ score were obtained during exercises and it was used to construction of four complex network models. Such models have both, theoretical and mathematical value, and enables us to perceive new insights that go beyond conventional analysis. From these, we ranked the influences of each node at the fatigue process. Our results shows that nodes, links and network metrics are sensibility according to increase of efforts intensities, been the velocity a key factor to exercise maintenance at models/intensities 1 and 2 (higher time efforts) and force and power at models 3 and 4, highlighting mechanical variables in the exhaustion occurrence and even training prescription applications. PMID:25994386

  9. Locomotor muscle fatigue increases cardiorespiratory responses and reduces performance during intense cycling exercise independently from metabolic stress.

    PubMed

    Marcora, Samuele M; Bosio, Andrea; de Morree, Helma M

    2008-03-01

    Locomotor muscle fatigue, defined as an exercise-induced reduction in maximal voluntary force, occurs during prolonged exercise, but its effects on cardiorespiratory responses and exercise performance are unknown. In this investigation, a significant reduction in locomotor muscle force (-18%, P < 0.05) was isolated from the metabolic stress usually associated with fatiguing exercise using a 100-drop-jumps protocol consisting of one jump every 20 s from a 40-cm-high platform. The effect of this treatment on time to exhaustion during high-intensity constant-power cycling was measured in study 1 (n = 10). In study 2 (n = 14), test duration (871 +/- 280 s) was matched between fatigue and control condition (rest). In study 1, locomotor muscle fatigue caused a significant curtailment in time to exhaustion (636 +/- 278 s) compared with control (750 +/- 281 s) (P = 0.003) and increased cardiac output. Breathing frequency was significantly higher in the fatigue condition in both studies despite similar oxygen consumption and blood lactate accumulation. In study 2, high-intensity cycling did not induce further fatigue to eccentrically-fatigued locomotor muscles. In both studies, there was a significant increase in heart rate in the fatigue condition, and perceived exertion was significantly increased in study 2 compared with control. These results suggest that locomotor muscle fatigue has a significant influence on cardiorespiratory responses and exercise performance during high-intensity cycling independently from metabolic stress. These effects seem to be mediated by the increased central motor command and perception of effort required to exercise with weaker locomotor muscles. PMID:18184760

  10. Short-term high-intensity interval exercise training attenuates oxidative stress responses and improves antioxidant status in healthy humans.

    PubMed

    Bogdanis, G C; Stavrinou, P; Fatouros, I G; Philippou, A; Chatzinikolaou, A; Draganidis, D; Ermidis, G; Maridaki, M

    2013-11-01

    This study investigated the changes in oxidative stress biomarkers and antioxidant status indices caused by a 3-week high-intensity interval training (HIT) regimen. Eight physically active males performed three HIT sessions/week over 3 weeks. Each session included four to six 30-s bouts of high-intensity cycling separated by 4 min of recovery. Before training, acute exercise elevated protein carbonyls (PC), thiobarbituric acid reactive substances (TBARS), glutathione peroxidase (GPX) activity, total antioxidant capacity (TAC) and creatine kinase (CK), which peaked 24h post-exercise (252 ± 30%, 135 ± 17%, 10 ± 2%, 85 ± 14% and 36 ± 13%, above baseline, respectively; p<0.01), while catalase activity (CAT) peaked 30 min post-exercise (56 ± 18% above baseline; p<0.01). Training attenuated the exercise-induced increase in oxidative stress markers (PC by 13.3 ± 3.7%; TBARS by 7.2 ± 2.7%, p<0.01) and CK activity, despite the fact that total work done was 10.9 ± 3.6% greater in the post- compared with the pre-training exercise test. Training also induced a marked elevation of antioxidant status indices (TAC by 38.4 ± 7.2%; CAT by 26.2 ± 10.1%; GPX by 3.0 ± 0.6%, p<0.01). Short-term HIT attenuates oxidative stress and up-regulates antioxidant activity after only nine training sessions totaling 22 min of high intensity exercise, further supporting its positive effect not only on physical conditioning but also on health promotion.

  11. Influence of aerobic exercise intensity on myofibrillar and mitochondrial protein synthesis in young men during early and late postexercise recovery.

    PubMed

    Di Donato, Danielle M; West, Daniel W D; Churchward-Venne, Tyler A; Breen, Leigh; Baker, Steven K; Phillips, Stuart M

    2014-05-01

    Aerobic exercise is typically associated with expansion of the mitochondrial protein pool and improvements in muscle oxidative capacity. The impact of aerobic exercise intensity on the synthesis of specific skeletal muscle protein subfractions is not known. We aimed to study the effect of aerobic exercise intensity on rates of myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis over an early (0.5-4.5 h) and late (24-28 h) period during postexercise recovery. Using a within-subject crossover design, eight males (21 ± 1 yr, Vo2peak 46.7 ± 2.0 ml·kg(-1)·min(-1)) performed two work-matched cycle ergometry exercise trials (LOW: 60 min at 30% Wmax; HIGH: 30 min at 60% Wmax) in the fasted state while undergoing a primed constant infusion of l-[ring-(13)C6]phenylalanine. Muscle biopsies were obtained at rest and 0.5, 4.5, 24, and 28 h postexercise to determine both the "early" and "late" response of MyoPS and MitoPS and the phosphorylation status of selected proteins within both the Akt/mTOR and MAPK pathways. Over 24-28 h postexercise, MitoPS was significantly greater after the HIGH vs. LOW exercise trial (P < 0.05). Rates of MyoPS were increased equivalently over 0.5-4.5 h postexercise recovery (P < 0.05) but remained elevated at 24-28 h postexercise only following the HIGH trial. In conclusion, an acute bout of high- but not low-intensity aerobic exercise in the fasted state resulted in a sustained elevation of both MitoPS and MyoPS at 24-28 h postexercise recovery.

  12. Cardiac troponin T and echocardiographic dimensions after repeated sprint vs. moderate intensity continuous exercise in healthy young males

    PubMed Central

    Weippert, Matthias; Divchev, Dimitar; Schmidt, Paul; Gettel, Hannes; Neugebauer, Antina; Behrens, Kristin; Wolfarth, Bernd; Braumann, Klaus-Michael; Nienaber, Christoph A.

    2016-01-01

    Regular physical exercise can positively influence cardiac function; however, investigations have shown an increase of myocardial damage biomarkers after acute prolonged endurance exercises. We investigated the effect of repeated sprint vs. moderate long duration exercise on markers of myocardial necrosis, as well as cardiac dimensions and functions. Thirteen healthy males performed two different running sessions (randomized, single blinded cross-over design): 60 minutes moderate intensity continuous training (MCT, at 70% of peak heart rate (HRpeak)) and two series of 12 × 30-second sprints with set recovery periods in-between (RST, at 90% HRpeak). Venous blood samples for cardiac troponin T (cTnT), creatine kinase (CK) and MB isoenzyme (CK-MB) were taken 1 and 4 hours after exercise sessions. After each session electrocardiographic (ECG) and transthoracic echocardiographic (TTE) data were recorded. Results showed that all variables - average heart rate, serum lactate concentration during RST, subjective exertion and cTnT after RST - were significantly higher compared to MCT. CK and CK-MB significantly increased regardless of exercise protocol, while ECG and TTE indicated normal cardiac function. Our results provide evidence that RST contributes significantly to cTnT and CK release. This biomarker increase seems to reflect a physiological rather than a pathological phenomenon in healthy, exercising subjects. PMID:27090032

  13. Hippocampal structure, metabolism, and inflammatory response after a 6-week intense aerobic exercise in healthy young adults: a controlled trial.

    PubMed

    Wagner, Gerd; Herbsleb, Marco; de la Cruz, Feliberto; Schumann, Andy; Brünner, Franziska; Schachtzabel, Claudia; Gussew, Alexander; Puta, Christian; Smesny, Stefan; Gabriel, Holger W; Reichenbach, Jürgen R; Bär, Karl-Jürgen

    2015-10-01

    Interventional studies suggest that changes in physical fitness affect brain function and structure. We studied the influence of high intensity physical exercise on hippocampal volume and metabolism in 17 young healthy male adults during a 6-week exercise program compared with matched controls. We further aimed to relate these changes to hypothesized changes in exercised-induced brain-derived neurotrophic factor (BDNF), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α). We show profound improvement of physical fitness in most subjects and a positive correlation between the degree of fitness improvement and increased BDNF levels. We unexpectedly observed an average volume decrease of about 2%, which was restricted to right hippocampal subfields CA2/3, subiculum, and dentate gyrus and which correlated with fitness improvement and increased BDNF levels negatively. This result indicates that mainly those subjects who did not benefit from the exercise program show decreased hippocampal volume, reduced BDNF levels, and increased TNF-α concentrations. While spectroscopy results do not indicate any neuronal loss (unchanged N-acetylaspartate levels) decreased glutamate-glutamine levels were observed in the right anterior hippocampus in the exercise group only. Responder characteristics need to be studied in more detail. Our results point to an important role of the inflammatory response after exercise on changes in hippocampal structure. PMID:26082010

  14. Hippocampal structure, metabolism, and inflammatory response after a 6-week intense aerobic exercise in healthy young adults: a controlled trial.

    PubMed

    Wagner, Gerd; Herbsleb, Marco; de la Cruz, Feliberto; Schumann, Andy; Brünner, Franziska; Schachtzabel, Claudia; Gussew, Alexander; Puta, Christian; Smesny, Stefan; Gabriel, Holger W; Reichenbach, Jürgen R; Bär, Karl-Jürgen

    2015-10-01

    Interventional studies suggest that changes in physical fitness affect brain function and structure. We studied the influence of high intensity physical exercise on hippocampal volume and metabolism in 17 young healthy male adults during a 6-week exercise program compared with matched controls. We further aimed to relate these changes to hypothesized changes in exercised-induced brain-derived neurotrophic factor (BDNF), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α). We show profound improvement of physical fitness in most subjects and a positive correlation between the degree of fitness improvement and increased BDNF levels. We unexpectedly observed an average volume decrease of about 2%, which was restricted to right hippocampal subfields CA2/3, subiculum, and dentate gyrus and which correlated with fitness improvement and increased BDNF levels negatively. This result indicates that mainly those subjects who did not benefit from the exercise program show decreased hippocampal volume, reduced BDNF levels, and increased TNF-α concentrations. While spectroscopy results do not indicate any neuronal loss (unchanged N-acetylaspartate levels) decreased glutamate-glutamine levels were observed in the right anterior hippocampus in the exercise group only. Responder characteristics need to be studied in more detail. Our results point to an important role of the inflammatory response after exercise on changes in hippocampal structure.

  15. The development of peripheral fatigue and short-term recovery during self-paced high-intensity exercise.

    PubMed

    Froyd, Christian; Millet, Guillaume Y; Noakes, Timothy D

    2013-03-01

    The time course of muscular fatigue that develops during and after an intense bout of self-paced dynamic exercise was characterized by using different forms of electrical stimulation (ES) of the exercising muscles. Ten active subjects performed a time trial (TT) involving repetitive concentric extension/flexion of the right knee using a Biodex dynamometer. Neuromuscular function (NMF), including ES and a 5 s maximal isometric voluntary contraction (MVC), was assessed before the start of the TT and immediately (<5 s) after each 20% of the TT had been completed, as well as 1, 2, 4 and 8 min after TT termination. The TT time was 347 ± 98 s. MVCs were 52% of baseline values at TT termination. Torque responses from ES were reduced to 33-68% of baseline using different methods of stimulation, suggesting that the extent to which peripheral fatigue is documented during exercise depends upon NMF assessment methodology. The major changes in muscle function occurred within the first 40% of exercise. Significant recovery in skeletal muscle function occurs within the first 1-2 min after exercise, showing that previous studies may have underestimated the extent to which peripheral fatigue develops during exercise.

  16. Effect of intensive aerobic exercise on respiratory capacity and walking ability with chronic stroke patients: a randomized controlled pilot trial

    PubMed Central

    Bang, Dae-Hyouk; Son, Young-Lan

    2016-01-01

    [Purpose] To investigate the effects of intensive aerobic exercise on respiratory capacity and walking ability in chronic stroke patients. [Subjects and Methods] The subjects were randomly assigned to an experimental group (n=6) or a control group (n=6). Patients in the experimental group received intensive aerobic exercise for 30 minutes and traditional physical therapy once a day, five days a week, for four weeks. The control group received aerobic exercise for 30 minutes and traditional physical therapy for 30 minutes a day, five days a week, for four weeks. [Results] After the intervention, both groups showed significant improvements in the forced vital capacity, forced expiratory volume in one second, 10-meter walking test, and six-minute walking test over the baseline results. The comparison of the two groups after the intervention revealed that the experimental group showed more significant improvements in the forced vital capacity, forced expiratory volume in one second, and six-minute walking test. There was no significant difference in saturation pulse oximetry oxygen and 10-meter walking test between the groups. [Conclusion] The results of this study suggest that intensive aerobic exercise has a positive effect on respiratory capacity and walking endurance in patients with chronic stroke. PMID:27630438

  17. Effect of intensive aerobic exercise on respiratory capacity and walking ability with chronic stroke patients: a randomized controlled pilot trial.

    PubMed

    Bang, Dae-Hyouk; Son, Young-Lan

    2016-08-01

    [Purpose] To investigate the effects of intensive aerobic exercise on respiratory capacity and walking ability in chronic stroke patients. [Subjects and Methods] The subjects were randomly assigned to an experimental group (n=6) or a control group (n=6). Patients in the experimental group received intensive aerobic exercise for 30 minutes and traditional physical therapy once a day, five days a week, for four weeks. The control group received aerobic exercise for 30 minutes and traditional physical therapy for 30 minutes a day, five days a week, for four weeks. [Results] After the intervention, both groups showed significant improvements in the forced vital capacity, forced expiratory volume in one second, 10-meter walking test, and six-minute walking test over the baseline results. The comparison of the two groups after the intervention revealed that the experimental group showed more significant improvements in the forced vital capacity, forced expiratory volume in one second, and six-minute walking test. There was no significant difference in saturation pulse oximetry oxygen and 10-meter walking test between the groups. [Conclusion] The results of this study suggest that intensive aerobic exercise has a positive effect on respiratory capacity and walking endurance in patients with chronic stroke.

  18. Acute, intermediate intensity exercise, and speed and accuracy in working memory tasks: a meta-analytical comparison of effects.

    PubMed

    McMorris, Terry; Sproule, John; Turner, Anthony; Hale, Beverley J

    2011-03-01

    The purpose of this study was to compare, using meta-analytic techniques, the effect of acute, intermediate intensity exercise on the speed and accuracy of performance of working memory tasks. It was hypothesized that acute, intermediate intensity exercise would have a significant beneficial effect on response time and that effect sizes for response time and accuracy data would differ significantly. Random-effects meta-analysis showed a significant, beneficial effect size for response time, g=-1.41 (p<0.001) but a significant detrimental effect size, g=0.40 (p<0.01), for accuracy. There was a significant difference between effect sizes (Z(diff)=3.85, p<0.001). It was concluded that acute, intermediate intensity exercise has a strong beneficial effect on speed of response in working memory tasks but a low to moderate, detrimental one on accuracy. There was no support for a speed-accuracy trade-off. It was argued that exercise-induced increases in brain concentrations of catecholamines result in faster processing but increases in neural noise may negatively affect accuracy.

  19. Effect of intensive aerobic exercise on respiratory capacity and walking ability with chronic stroke patients: a randomized controlled pilot trial.

    PubMed

    Bang, Dae-Hyouk; Son, Young-Lan

    2016-08-01

    [Purpose] To investigate the effects of intensive aerobic exercise on respiratory capacity and walking ability in chronic stroke patients. [Subjects and Methods] The subjects were randomly assigned to an experimental group (n=6) or a control group (n=6). Patients in the experimental group received intensive aerobic exercise for 30 minutes and traditional physical therapy once a day, five days a week, for four weeks. The control group received aerobic exercise for 30 minutes and traditional physical therapy for 30 minutes a day, five days a week, for four weeks. [Results] After the intervention, both groups showed significant improvements in the forced vital capacity, forced expiratory volume in one second, 10-meter walking test, and six-minute walking test over the baseline results. The comparison of the two groups after the intervention revealed that the experimental group showed more significant improvements in the forced vital capacity, forced expiratory volume in one second, and six-minute walking test. There was no significant difference in saturation pulse oximetry oxygen and 10-meter walking test between the groups. [Conclusion] The results of this study suggest that intensive aerobic exercise has a positive effect on respiratory capacity and walking endurance in patients with chronic stroke. PMID:27630438

  20. Effect of intensive aerobic exercise on respiratory capacity and walking ability with chronic stroke patients: a randomized controlled pilot trial

    PubMed Central

    Bang, Dae-Hyouk; Son, Young-Lan

    2016-01-01

    [Purpose] To investigate the effects of intensive aerobic exercise on respiratory capacity and walking ability in chronic stroke patients. [Subjects and Methods] The subjects were randomly assigned to an experimental group (n=6) or a control group (n=6). Patients in the experimental group received intensive aerobic exercise for 30 minutes and traditional physical therapy once a day, five days a week, for four weeks. The control group received aerobic exercise for 30 minutes and traditional physical therapy for 30 minutes a day, five days a week, for four weeks. [Results] After the intervention, both groups showed significant improvements in the forced vital capacity, forced expiratory volume in one second, 10-meter walking test, and six-minute walking test over the baseline results. The comparison of the two groups after the intervention revealed that the experimental group showed more significant improvements in the forced vital capacity, forced expiratory volume in one second, and six-minute walking test. There was no significant difference in saturation pulse oximetry oxygen and 10-meter walking test between the groups. [Conclusion] The results of this study suggest that intensive aerobic exercise has a positive effect on respiratory capacity and walking endurance in patients with chronic stroke.

  1. Exercise Training in Group 2 Pulmonary Hypertension: Which Intensity and What Modality.

    PubMed

    Arena, Ross; Lavie, Carl J; Borghi-Silva, Audrey; Daugherty, John; Bond, Samantha; Phillips, Shane A; Guazzi, Marco

    2016-01-01

    Pulmonary hypertension (PH) due to left-sided heart disease (LSHD) is a common and disconcerting occurrence. For example, both heart failure (HF) with preserved and reduced ejection fraction (HFpEF and HFrEF) often lead to PH as a consequence of a chronic elevation in left atrial filling pressure. A wealth of literature demonstrates the value of exercise training (ET) in patients with LSHD, which is particularly robust in patients with HFrEF and growing in patients with HFpEF. While the effects of ET have not been specifically explored in the LSHD-PH phenotype (i.e., composite pathophysiologic characteristics of patients in this advanced disease state), the overall body of evidence supports clinical application in this subgroup. Moderate intensity aerobic ET significantly improves peak oxygen consumption, quality of life and prognosis in patients with HF. Resistance ET significantly improves muscle strength and endurance in patients with HF, which further enhance functional capacity. When warranted, inspiratory muscle training and neuromuscular electrical stimulation are becoming recognized as important components of a comprehensive rehabilitation program. This review will provide a detailed account of ET programing considerations in patients with LSHD with a particular focus on those concomitantly diagnosed with PH. PMID:26569571

  2. Cardiorespiratory and Metabolic Responses to Loaded Half Squat Exercise Executed at an Intensity Corresponding to the Lactate Threshold.

    PubMed

    Maté-Muñoz, José Luis; Domínguez, Raúl; Barba, Manuel; Monroy, Antonio J; Rodríguez, Bárbara; Ruiz-Solano, Pedro; Garnacho-Castaño, Manuel V

    2015-09-01

    This study was designed to identify the blood lactate threshold (LT2) for the half squat (HS) and to examine cardiorespiratory and metabolic variables during a HS test performed at a work intensity corresponding to the LT2. Twenty-four healthy men completed 3 test sessions. In the first, their one-repetition maximum (1RM) was determined for the HS. In the second session, a resistance HS incremental-load test was performed to determine LT2. Finally, in the third session, subjects performed a constant-load HS exercise at the load corresponding to the LT2 (21 sets of 15 repetitions with 1 min of rest between sets). In this last test, blood samples were collected for lactate determination before the test and 30 s after the end of set (S) 3, S6, S9, S12, S15, S18 and S21. During the test, heart rate (HR) was telemetrically monitored and oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), respiratory exchange ratio (RER), ventilatory equivalent for O2 (VE·VO2 (-1)) and ventilatory equivalent for CO2 (VE·VCO2 (-1)) were monitored using a breath-by-breath respiratory gas analyzer. The mean LT2 for the participants was 24.8 ± 4.8% 1RM. Blood lactate concentrations showed no significant differences between sets 3 and 21 of exercise (p = 1.000). HR failed to vary between S6 and S21 (p > 1.000). The respiratory variables VO2, VCO2, and VE·VCO2 (-1) stabilized from S3 to the end of the constant-load HS test (p = 0.471, p = 0.136, p = 1.000), while VE and VE·VO2 (-1) stabilized from S6 to S21. RER did not vary significantly across exercise sets (p = 0.103). The LT2 was readily identified in the incremental HS test. Cardiorespiratory and metabolic variables remained stable during this resistance exercise conducted at an exercise intensity corresponding to the LT2. These responses need to be confirmed for other resistance exercises and adaptations in these responses after a training program also need to be addressed. Key pointsIt can be

  3. Cardiorespiratory and Metabolic Responses to Loaded Half Squat Exercise Executed at an Intensity Corresponding to the Lactate Threshold

    PubMed Central

    Maté-Muñoz, José Luis; Domínguez, Raúl; Barba, Manuel; Monroy, Antonio J.; Rodríguez, Bárbara; Ruiz-Solano, Pedro; Garnacho-Castaño, Manuel V.

    2015-01-01

    This study was designed to identify the blood lactate threshold (LT2) for the half squat (HS) and to examine cardiorespiratory and metabolic variables during a HS test performed at a work intensity corresponding to the LT2. Twenty-four healthy men completed 3 test sessions. In the first, their one-repetition maximum (1RM) was determined for the HS. In the second session, a resistance HS incremental-load test was performed to determine LT2. Finally, in the third session, subjects performed a constant-load HS exercise at the load corresponding to the LT2 (21 sets of 15 repetitions with 1 min of rest between sets). In this last test, blood samples were collected for lactate determination before the test and 30 s after the end of set (S) 3, S6, S9, S12, S15, S18 and S21. During the test, heart rate (HR) was telemetrically monitored and oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), respiratory exchange ratio (RER), ventilatory equivalent for O2 (VE·VO2-1) and ventilatory equivalent for CO2 (VE·VCO2-1) were monitored using a breath-by-breath respiratory gas analyzer. The mean LT2 for the participants was 24.8 ± 4.8% 1RM. Blood lactate concentrations showed no significant differences between sets 3 and 21 of exercise (p = 1.000). HR failed to vary between S6 and S21 (p > 1.000). The respiratory variables VO2, VCO2, and VE·VCO2-1 stabilized from S3 to the end of the constant-load HS test (p = 0.471, p = 0.136, p = 1.000), while VE and VE·VO2-1 stabilized from S6 to S21. RER did not vary significantly across exercise sets (p = 0.103). The LT2 was readily identified in the incremental HS test. Cardiorespiratory and metabolic variables remained stable during this resistance exercise conducted at an exercise intensity corresponding to the LT2. These responses need to be confirmed for other resistance exercises and adaptations in these responses after a training program also need to be addressed. Key points It can be identified

  4. Exercise intensity and muscle hypertrophy in blood flow-restricted limbs and non-restricted muscles: a brief review.

    PubMed

    Abe, Takashi; Loenneke, Jeremy P; Fahs, Christopher A; Rossow, Lindy M; Thiebaud, Robert S; Bemben, Michael G

    2012-07-01

    Although evidence for high-intensity resistance training-induced muscle hypertrophy has accumulated over the last several decades, the basic concept of the training can be traced back to ancient Greece: Milo of Croton lifted a bull-calf daily until it was fully grown, which would be known today as progressive overload. Now, in the 21st century, different types of training are being tested and studied, such as low-intensity exercise combined with arterial as well as venous blood flow restriction (BFR) to/from the working muscles. Because BFR training requires the use of a cuff that is placed at the proximal ends of the arms and/or legs, the BFR is only applicable to limb muscles. Consequently, most previous BFR training studies have focused on the physiological adaptations of BFR limb muscles. Muscle adaptations in non-BFR muscles of the hip and trunk are lesser known. Recent studies that have reported both limb and trunk muscle adaptations following BFR exercise training suggest that low-intensity (20-30% of 1RM) resistance training combined with BFR elicits muscle hypertrophy in both BFR limb and non-BFR muscles. However, the combination of leg muscle BFR with walk training elicits muscle hypertrophy only in the BFR leg muscles. In contrast to resistance exercise with BFR, the exercise intensity may be too low during BFR walk training to cause muscle hypertrophy in the non-BFR gluteus maximus and other trunk muscles. Other mechanisms including hypoxia, local and systemic growth factors and muscle cell swelling may also potentially affect the hypertrophic response of non-BFR muscles to BFR resistance exercise.

  5. Effect of moderate-intensity exercise training on the cognitive function of young adults with intellectual disabilities.

    PubMed

    Pastula, Robert M; Stopka, Christine B; Delisle, Anthony T; Hass, Chris J

    2012-12-01

    In addition to cognitive impairment, young adults with intellectual disabilities (IDs) are also more likely to be in poor health. Exercise may help ameliorate both of these deficits. While the health benefits of exercise are well documented and understood, the cognitive benefits of exercise are emerging. Exercise has been shown to improve the cognitive function of young, old, and diseased populations but few studies have evaluated the effect of exercise training on the cognitive functioning of individuals with IDs. The purpose of this study was to determine the effect of moderate-intensity exercise training on the cognitive function of young adults with IDs. Fourteen students (age, 19.4 ± 1.3 years) with mild to moderate IDs participated in an 8-week comprehensive exercise intervention program based on circuit training, aerobic dancing, and adapted sport activities. Sessions lasted 45 minutes, and intensity was maintained at 60-70% of maximum heart rate (HR(max)). Aerobic fitness was assessed via the Young Men's Christian Association (YMCA) step test, and intellectual functioning was assessed via 3 subtests from the Woodcock-Johnson III Tests of Cognitive Abilities once before and after the intervention. Performance was significantly improved on all 3 cognitive tests (all, p < 0.002). Aerobic fitness also significantly improved (p < 0.002). The mean percent increase in processing speed, a measure taking into account each individual's performance on the 3 subtests, was 103%. The mean individual improvement in aerobic fitness was 17.5%. Moderate-intensity exercise training can yield robust improvements in the cognitive functioning and aerobic fitness of young adults with IDs. These effects support the inclusion of exercise into the lives of young adults with ID to promote their physical and cognitive health. Fourteen students (age, 19.4 ± 1.3 years) with mild to moderate IDs participated in an 8-week comprehensive exercise intervention program based on circuit

  6. Association between the increase in brain temperature and physical performance at different exercise intensities and protocols in a temperate environment

    PubMed Central

    Kunstetter, A.C.; Wanner, S.P.; Madeira, L.G.; Wilke, C.F.; Rodrigues, L.O.C.; Lima, N.R.V.

    2014-01-01

    There is evidence that brain temperature (Tbrain) provides a more sensitive index than other core body temperatures in determining physical performance. However, no study has addressed whether the association between performance and increases in Tbrain in a temperate environment is dependent upon exercise intensity, and this was the primary aim of the present study. Adult male Wistar rats were subjected to constant exercise at three different speeds (18, 21, and 24 m/min) until the onset of volitional fatigue. Tbrain was continuously measured by a thermistor inserted through a brain guide cannula. Exercise induced a speed-dependent increase in Tbrain, with the fastest speed associated with a higher rate of Tbrain increase. Rats subjected to constant exercise had similar Tbrain values at the time of fatigue, although a pronounced individual variability was observed (38.7-41.7°C). There were negative correlations between the rate of Tbrain increase and performance for all speeds that were studied. These results indicate that performance during constant exercise is negatively associated with the increase in Tbrain, particularly with its rate of increase. We then investigated how an incremental-speed protocol affected the association between the increase in Tbrain and performance. At volitional fatigue, Tbrain was lower during incremental exercise compared with the Tbrain resulting from constant exercise (39.3±0.3 vs 40.3±0.1°C; P<0.05), and no association between the rate of Tbrain increase and performance was observed. These findings suggest that the influence of Tbrain on performance under temperate conditions is dependent on exercise protocol. PMID:25003543

  7. Association between the increase in brain temperature and physical performance at different exercise intensities and protocols in a temperate environment.

    PubMed

    Kunstetter, A C; Wanner, S P; Madeira, L G; Wilke, C F; Rodrigues, L O C; Lima, N R V

    2014-08-01

    There is evidence that brain temperature (T brain) provides a more sensitive index than other core body temperatures in determining physical performance. However, no study has addressed whether the association between performance and increases in T brain in a temperate environment is dependent upon exercise intensity, and this was the primary aim of the present study. Adult male Wistar rats were subjected to constant exercise at three different speeds (18, 21, and 24 m/min) until the onset of volitional fatigue. T brain was continuously measured by a thermistor inserted through a brain guide cannula. Exercise induced a speed-dependent increase in T brain, with the fastest speed associated with a higher rate of T brain increase. Rats subjected to constant exercise had similar T brain values at the time of fatigue, although a pronounced individual variability was observed (38.7-41.7°C). There were negative correlations between the rate of T brain increase and performance for all speeds that were studied. These results indicate that performance during constant exercise is negatively associated with the increase in T brain, particularly with its rate of increase. We then investigated how an incremental-speed protocol affected the association between the increase in T brain and performance. At volitional fatigue, T brain was lower during incremental exercise compared with the T brain resulting from constant exercise (39.3 ± 0.3 vs 40.3 ± 0.1°C; P<0.05), and no association between the rate of T brain increase and performance was observed. These findings suggest that the influence of T brain on performance under temperate conditions is dependent on exercise protocol.

  8. 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. PMID:27467217

  9. 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.

  10. 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.

  11. Erythropoietin does not reduce plasma lactate, H⁺, and K⁺ during intense exercise.

    PubMed

    Nordsborg, N B; Robach, P; Boushel, R; Calbet, J A L; Lundby, C

    2015-12-01

    It is investigated if recombinant human erythropoietin (rHuEPO) treatment for 15 weeks (n = 8) reduces extracellular accumulation of metabolic stress markers such as lactate, H(+) , and K(+) during incremental exhaustive exercise. After rHuEPO treatment, normalization of blood volume and composition by hemodilution preceded an additional incremental test. Group averages were calculated for an exercise intensity ∼80% of pre-rHuEPO peak power output. After rHuEPO treatment, leg lactate release to the plasma compartment was similar to before (4.3 ± 1.6 vs 3.9 ± 2.5 mmol/min) and remained similar after hemodilution. Venous lactate concentration was higher (P < 0.05) after rHuEPO treatment (7.1 ± 1.6 vs 5.2 ± 2.1 mM). Leg H(+) release to the plasma compartment after rHuEPO was similar to before (19.6 ± 5.4 vs 17.6 ± 6.0 mmol/min) and remained similar after hemodilution. Nevertheless, venous pH was lower (P < 0.05) after rHuEPO treatment (7.18 ± 0.04 vs 7.22 ± 0.05). Leg K(+) release to the plasma compartment after rHuEPO treatment was similar to before (0.8 ± 0.5 vs 0.7 ± 0.7 mmol/min) and remained similar after hemodilution. Additionally, venous K(+) concentrations were similar after vs before rHuEPO (5.3 ± 0.3 vs 5.1 ± 0.4 mM). In conclusion, rHuEPO does not reduce plasma accumulation of lactate, H(+) , and K(+) at work rates corresponding to ∼80% of peak power output. PMID:25556620

  12. Physiological effects of two different postactivation potentiation training loads on power profiles generated during high intensity cycle ergometer exercise.

    PubMed

    Parry, Sian; Hancock, Stuart; Shiells, Matthew; Passfield, Louis; Davies, Bruce; Baker, Julien S

    2008-01-01

    The purpose of this study was to investigate whether postactivation potentiation (PAP) would have any effect on high intensity cycle ergometer performance. Two different squatting exercises of different loads were presented in a random fashion prior to ergometric exercise. Seven male rugby players volunteered to participate in the study. There were no significant differences observed between peak power output (PPO) measurements for all three testing conditions (P > 0.05). There were also no differences recorded between mean power outputs (MPOs) and end power outputs (EPOs) (P > 0.05). The decrease in power output (FI %) also was found to be nonsignificant for all conditions (P > 0.05). The findings of this study indicate that performance of repeated heavy squats prior to a 30-second maximal cycle ergometer exercise did not improve the power profiles recorded and did not induce PAP at the time of testing.

  13. Absolute biological needs.

    PubMed

    McLeod, Stephen

    2014-07-01

    Absolute needs (as against instrumental needs) are independent of the ends, goals and purposes of personal agents. Against the view that the only needs are instrumental needs, David Wiggins and Garrett Thomson have defended absolute needs on the grounds that the verb 'need' has instrumental and absolute senses. While remaining neutral about it, this article does not adopt that approach. Instead, it suggests that there are absolute biological needs. The absolute nature of these needs is defended by appeal to: their objectivity (as against mind-dependence); the universality of the phenomenon of needing across the plant and animal kingdoms; the impossibility that biological needs depend wholly upon the exercise of the abilities characteristic of personal agency; the contention that the possession of biological needs is prior to the possession of the abilities characteristic of personal agency. Finally, three philosophical usages of 'normative' are distinguished. On two of these, to describe a phenomenon or claim as 'normative' is to describe it as value-dependent. A description of a phenomenon or claim as 'normative' in the third sense does not entail such value-dependency, though it leaves open the possibility that value depends upon the phenomenon or upon the truth of the claim. It is argued that while survival needs (or claims about them) may well be normative in this third sense, they are normative in neither of the first two. Thus, the idea of absolute need is not inherently normative in either of the first two senses. PMID:23586876

  14. Absolute biological needs.

    PubMed

    McLeod, Stephen

    2014-07-01

    Absolute needs (as against instrumental needs) are independent of the ends, goals and purposes of personal agents. Against the view that the only needs are instrumental needs, David Wiggins and Garrett Thomson have defended absolute needs on the grounds that the verb 'need' has instrumental and absolute senses. While remaining neutral about it, this article does not adopt that approach. Instead, it suggests that there are absolute biological needs. The absolute nature of these needs is defended by appeal to: their objectivity (as against mind-dependence); the universality of the phenomenon of needing across the plant and animal kingdoms; the impossibility that biological needs depend wholly upon the exercise of the abilities characteristic of personal agency; the contention that the possession of biological needs is prior to the possession of the abilities characteristic of personal agency. Finally, three philosophical usages of 'normative' are distinguished. On two of these, to describe a phenomenon or claim as 'normative' is to describe it as value-dependent. A description of a phenomenon or claim as 'normative' in the third sense does not entail such value-dependency, though it leaves open the possibility that value depends upon the phenomenon or upon the truth of the claim. It is argued that while survival needs (or claims about them) may well be normative in this third sense, they are normative in neither of the first two. Thus, the idea of absolute need is not inherently normative in either of the first two senses.

  15. Construct and Concurrent Validation of a New Resistance Intensity Scale for Exercise with Thera-Band® Elastic Bands

    PubMed Central

    Colado, Juan C.; Garcia-Masso, Xavier; Triplett, N. Travis; Calatayud, Joaquin; Flandez, Jorge; Behm, David; Rogers, Michael E.

    2014-01-01

    The construct and concurrent validity of the Thera-Band Perceived Exertion Scale for Resistance Exercise with elastic bands (EB) was examined. Twenty subjects performed two separate sets of 15 repetitions of both frontal and lateral raise exercise over two sessions. The criterion variables were myoelectric activity and heart rate. One set was performed with an elastic band grip width that permitted 15 maximum repetitions in the selected exercise, and another set was performed with a grip width 50% more than the 15RM grip. Following the final repetition of each set, active muscle (AM) and overall body (O) ratings of perceived exertion (RPE) were collected from the Thera-Band® resistance exercise scale and the OMNI-Resistance Exercise Scale of perceived exertion with Thera-Band® resistance bands (OMNI-RES EB). Construct validity was established by correlating the RPE from the OMNI-RES EB with the Thera-Band RPE scale using regression analysis. The results showed significant differences (p ≤ 0.05) in myoelectric activity, heart rate, and RPE scores between the low- and high-intensity sets. The intraclass correlation coefficient for active muscles and overall RPE scale scores was 0.67 and 0.58, respectively. There was a positive linear relationship between the RPE from the OMNI-RES EB and the Thera-Band scale. Validity coefficients for the RPE AM were r2 = 0.87 and ranged from r2 = 0.76 to 0.85 for the RPE O. Therefore, the Thera-Band Perceived Exertion Scale for Resistance Exercise can be used for monitoring elastic band exercise intensity. This would allow the training dosage to be better controlled within and between sessions. Moreover, the construct and concurrent validity indicates that the OMNI-RES EB measures similar properties of exertion as the Thera-Band RPE scale during elastic resistance exercise. Key points This new resistance intensity scale is an appropriate and valid tool for assessing perceived exertion during strength training with elastic bands

  16. Low intensity exercise prevents disturbances in rat cardiac insulin signaling and endothelial nitric oxide synthase induced by high fructose diet.

    PubMed

    Stanišić, Jelena; Korićanac, Goran; Ćulafić, Tijana; Romić, Snježana; Stojiljković, Mojca; Kostić, Milan; Pantelić, Marija; Tepavčević, Snežana

    2016-01-15

    Increase in fructose consumption together with decrease in physical activity contributes to the development of metabolic syndrome and consequently cardiovascular diseases. The current study examined the preventive role of exercise on defects in cardiac insulin signaling and function of endothelial nitric oxide synthase (eNOS) in fructose fed rats. Male Wistar rats were divided into control, sedentary fructose (received 10% fructose for 9 weeks) and exercise fructose (additionally exposed to low intensity exercise) groups. Concentration of triglycerides, glucose, insulin and visceral adipose tissue weight were determined to estimate metabolic syndrome development. Expression and/or phosphorylation of cardiac insulin receptor (IR), insulin receptor substrate 1 (IRS1), tyrosine-specific protein phosphatase 1B (PTP1B), Akt, extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and eNOS were evaluated. Fructose overload increased visceral adipose tissue, insulin concentration and homeostasis model assessment index. Exercise managed to decrease visceral adiposity and insulin level and to increase insulin sensitivity. Fructose diet increased level of cardiac PTP1B and pIRS1 (Ser307), while levels of IR and ERK1/2, as well as pIRS1 (Tyr 632), pAkt (Ser473, Thr308) and pERK1/2 were decreased. These disturbances were accompanied by reduced phosphorylation of eNOS at Ser1177. Exercise managed to prevent most of the disturbances in insulin signaling caused by fructose diet (except phosphorylation of IRS1 at Tyr 632 and phosphorylation and protein expression of ERK1/2) and consequently restored function of eNOS. Low intensity exercise could be considered as efficient treatment of cardiac insulin resistance induced by fructose diet.

  17. Effects of elevated core temperature and normoxic 30% nitrous oxide on human ventilation during short duration, high intensity exercise.

    PubMed

    Yogev, A; Hall, A M; Jay, O; White, M D

    2015-01-15

    It was hypothesized that normoxic 30% nitrous oxide (N2O) would suppress and hyperthermia would increase exercise ventilation during short duration, high intensity exercise. Thirteen males (24.2±0.8y; mean±SE), of normal physique (BMI, 23.8±1.0kgm(-2)), performed 4 separate 30s Wingate tests on a cycle ergometer. Exercise ventilation and its components, as well as mean skin and esophageal temperature (TES), were assessed in 2 way experimental design with factors of Thermal State (Normothermia or Hyperthermia) and Gas Type (Air or 30% Normomoxic N2O). In the 2 hyperthermic tests TES was elevated to ∼38.5°C in a 40°C bath. The main results indicated a significant interaction (F=7.14, P=0.02) between Gas Type and Thermal state for the exercise-induced increase in ventilation (ΔV˙E). During both the normothermia and hyperthermia conditions with AIR breathing, the exercise ΔV˙E was ∼80Lmin(-1) and it was significantly decreased to 73.1±24.1Lmin(-1) in the normothermia condition with N2O breathing relative to that of 92.0±25.0Lmin(-1) in the hyperthermia condition with N2O breathing. In conclusion, normoxic N2O breathing suppressed high intensity exercise ventilation during normothermia relative to that during hyperthermia on account of decreases in the tidal volume and this led CO2 retention.

  18. Intensive resistance exercise and circadian salivary testosterone concentrations among young male recreational lifters.

    PubMed

    Shariat, Ardalan; Kargarfard, Mehdi; Danaee, Mahmoud; Bahri Mohd Tamrin, Shamsul

    2015-01-01

    Strength and morphological adaptations to resistance exercise are mediated in part by anabolic hormones such as testosterone, yet the time course of variability in circadian hormone concentrations is not well characterized. This study, investigated how the circadian rhythm of salivary testosterone is altered by resistance exercise in young men. Twenty healthy young male recreational lifters (age, 18.0 ± 1.3 years) with 2 years of experience in weightlifting were recruited. A randomized controlled trial was conducted, and subjects were randomly assigned to either the resistance exercise group (n = 10), who completed a series of resistance exercise (3 times a week, in the afternoon, 6-7 repetitions, at 85% of 1 repetition maximum for 3 weeks), or a control group (n = 10), who did not exercise during the 3 weeks. Before and after the study, an unstimulated saliva sample (2 ml) was taken every 2 hours for a maximum of 16 hours during each day. A significant decrease was observed in the resistance exercise (44.2%, p = 0.001) and control group (46.1%, p = 0.001) for salivary testosterone at each time point compared with baseline (p = 0.001). There was also no significant difference between the exercise and resting conditions in both groups for salivary testosterone (p > 0.05), except a significantly higher increase by 38.4% vs. -0.02% (p = 0.001), at 1730 hours during exercise sessions in the resistance exercise group compared with the control group. Resistance exercise has no noteworthy effect on circadian secretion of salivary testosterone throughout the 16 waking hours. These results indicate that athletes can undertake resistance exercise in either the morning or afternoon with the knowledge that a similar testosterone response can be expected regardless of the time of day.

  19. Vitamin D3 supplementation modulates inflammatory responses from the muscle damage induced by high-intensity exercise in SD rats.

    PubMed

    Choi, Munji; Park, Hyon; Cho, Seongsuk; Lee, Myoungsook

    2013-07-01

    Vitamin D is an important factor for calcium and phosphorus homeostasis. A negative relationship has been observed between vitamin D status and diseases such as cancer, arthritis, diabetes, and muscle fiber atrophy. However, the relationship between vitamin D and prevention of skeletal muscle damage has not been clearly elucidated. The purpose of this study was to investigate the effects of vitamin D on exercise-induced muscle changes. Rats were divided into 3 groups: (1) sedentary control (C: n=10), (2) high-intensity exercise (HE: n=10), and (3) high-intensity exercise with vitamin D supplementation (HED: n=10; i.p. 1000 IU/kg body weight). Rats were trained for 30 min/day on treadmills (5 days/week for 8 weeks) with the running speed gradually increased up to 30 m/min at a 3° incline. At the end of the training period, the running speed was 38 m/min at a 5° incline. The high-intensity exercise significantly increased plasma creatine kinase (CK) and lactate dehydrogenase (LDH) activity. In addition, IL-6 and TNF-α levels as well as phosphorylation of AMPK, p38, ERK1/2, IKK, and IκB were significantly increased. Vitamin D-treated rats showed a significant decrease in plasma CK level, phosphorylation of AMPK, p38, ERK1/2, IKK, and IκB, and gene expression of IL-6 and TNF-α. Furthermore, the protein expression of vitamin D receptor (VDR) was highly increased in the muscles of HED-treated rats, respectively. Therefore, we concluded that vitamin D may play a pivotal role in exercise-induced muscle damage and inflammation through the modulation of MAPK and NF-κB involved with VDR. PMID:23669253

  20. Novel, high-intensity exercise prescription improves muscle mass, mitochondrial function, and physical capacity in individuals with Parkinson's disease

    PubMed Central

    Kelly, Neil A.; Ford, Matthew P.; Standaert, David G.; Watts, Ray L.; Bickel, C. Scott; Moellering, Douglas R.; Tuggle, S. Craig; Williams, Jeri Y.; Lieb, Laura; Windham, Samuel T.

    2014-01-01

    We conducted, in persons with Parkinson's disease (PD), a thorough assessment of neuromotor function and performance in conjunction with phenotypic analyses of skeletal muscle tissue, and further tested the adaptability of PD muscle to high-intensity exercise training. Fifteen participants with PD (Hoehn and Yahr stage 2–3) completed 16 wk of high-intensity exercise training designed to simultaneously challenge strength, power, endurance, balance, and mobility function. Skeletal muscle adaptations (P < 0.05) to exercise training in PD included myofiber hypertrophy (type I: +14%, type II: +36%), shift to less fatigable myofiber type profile, and increased mitochondrial complex activity in both subsarcolemmal and intermyofibrillar fractions (I: +45–56%, IV: +39–54%). These adaptations were accompanied by a host of functional and clinical improvements (P < 0.05): total body strength (+30–56%); leg power (+42%); single leg balance (+34%); sit-to-stand motor unit activation requirement (−30%); 6-min walk (+43 m), Parkinson's Disease Quality of Life Scale (PDQ-39, −7.8pts); Unified Parkinson's Disease Rating Scale (UPDRS) total (−5.7 pts) and motor (−2.7 pts); and fatigue severity (−17%). Additionally, PD subjects in the pretraining state were compared with a group of matched, non-PD controls (CON; did not exercise). A combined assessment of muscle tissue phenotype and neuromuscular function revealed a higher distribution and larger cross-sectional area of type I myofibers and greater type II myofiber size heterogeneity in PD vs. CON (P < 0.05). In conclusion, persons with moderately advanced PD adapt to high-intensity exercise training with favorable changes in skeletal muscle at the cellular and subcellular levels that are associated with improvements in motor function, physical capacity, and fatigue perception. PMID:24408997

  1. High-intensity interval exercise induces 24-h energy expenditure similar to traditional endurance exercise despite reduced time commitment.

    PubMed

    Skelly, Lauren E; Andrews, Patricia C; Gillen, Jenna B; Martin, Brian J; Percival, Michael E; Gibala, Martin J

    2014-07-01

    Subjects performed high-intensity interval training (HIIT) and continuous moderate-intensity training (END) to evaluate 24-h oxygen consumption. Oxygen consumption during HIIT was lower versus END; however, total oxygen consumption over 24 h was similar. These data demonstrate that HIIT and END induce similar 24-h energy expenditure, which may explain the comparable changes in body composition reported despite lower total training volume and time commitment.

  2. Acute effects of a thermogenic nutritional supplement on energy expenditure and cardiovascular function at rest, during low-intensity exercise, and recovery from exercise.

    PubMed

    Ryan, Eric D; Beck, Travis W; Herda, Trent J; Smith, Abbie E; Walter, Ashley A; Stout, Jeffrey R; Cramer, Joel T

    2009-05-01

    The purpose of present study was to examine the acute effects of a thermogenic nutritional supplement on energy expenditure (EE) and cardiovascular function at rest, during low-intensity exercise, and recovery from exercise. Twenty-eight healthy sedentary participants (mean +/- SD; age, 22.3 +/- 1.9 years; body mass index, 24.0 +/- 3.7) volunteered for this randomized, double-blinded, placebo-controlled, crossover study. Each experimental trial was divided into 4 phases: (a) 30 minutes of initial resting, followed by the placebo or thermogenic nutritional supplementation, (b) 50 minutes of postsupplementation resting, (c) 60 minutes of treadmill walking (3.2-4.8 km x h), and (d) 50 minutes of postexercise recovery. Gas exchange variables measured by indirect calorimetry and heart rate (HR) were recorded during all 4 phases, blood pressure was only measured at rest, and rating of perceived exertion (RPE) was only recorded during exercise. EE and oxygen consumption rate (Vo2) were greater for the supplement than the placebo at 50 minutes after supplementation. Also, during the postsupplementation period, diastolic blood pressure (DBP) was higher at all time periods, whereas the respiratory exchange ratio (RER) was higher at 20 and 30 minutes for the supplement. During exercise, only Vo2 and minute ventilation (VE) were greater for the supplement than the placebo, with HR being less than the placebo at 20 minutes for the men. Postexercise EE, Vo2, systolic blood pressure (SBP), DBP, and HR (men only) at 10, 20, 30, and 50 minutes were greater for the supplement than the placebo. These findings indicated that the thermogenic nutritional supplement increased resting EE and exercise Vo2 with only minimal effects on blood pressure and HR and no meaningful effects on RER or RPE. These results suggested that the combination of thermogenic ingredients in this nutritional supplement may be useful to help maintain a negative caloric balance but may not influence substrate use

  3. Small angle neutron scattering on an absolute intensity scale and the internal surface of diatom frustules from three species of differing morphologies.

    PubMed

    Garvey, C J; Strobl, M; Percot, A; Saroun, J; Haug, J; Vyverman, W; Chepurnov, V A; Ferris, J M

    2013-05-01

    The internal nanostructure of the diatoms Cyclotella meneghiniana, Seminavis robusta and Achnanthes subsessilis was investigated using small angle neutron scattering (SANS) to examine thin biosilica samples, consisting of isotropic (powder) from their isolated cell walls. The interpretation of SANS data was assisted by several other measurements. The N2 adsorption, interpreted within the Branuer-Emmet-Teller isotherm, yielded the specific surface area of the material. Fourier transform infrared (FTIR) and Raman spectroscopy indicates that the isolated material is amorphous silica with small amounts of organic cell wall materials acting as a filling material between the silica particles. A two-phase (air and amorphous silica) model was used to interpret small angle neutron scattering data. After correction for instrumental resolution, the measurements on two SANS instruments covered an extended range of scattering vectors 0.0011 nm(-1) < q < 5.6 nm(-1), giving an almost continuous SANS curve over a range of scattering vectors, q, on an absolute scale of intensity for each sample. Each of the samples gave a characteristic scattering curve where log (intensity) versus log (q) has a -4 dependence, with other features superimposed. In the high-q regime, departure from this behaviour was observed at a length-scales equivalent to the proposed unitary silica particle. The limiting Porod scattering law was used to determine the specific area per unit of volume of each sample illuminated by the neutron beam. The Porod behaviour, and divergence from this behaviour, is discussed in terms of various structural features and the proposed mechanisms for the bio-assembly of unitary silica particles in frustules.

  4. A High-Intensity, Intermittent Exercise Protocol and Dynamic Postural Control in Men and Women

    PubMed Central

    Whyte, Enda; Burke, Aoife; White, Elaine; Moran, Kieran

    2015-01-01

    Context: Deficits in dynamic postural control predict lower limb injury. Differing fatiguing protocols negatively affect dynamic postural control. The effect of high-intensity, intermittent exercise on dynamic postural control has not been investigated. Objective: To investigate the effect of a high-intensity, intermittent exercise protocol (HIIP) on the dynamic postural control of men and women as measured by the Star Excursion Balance Test (SEBT). Design: Descriptive laboratory study. Setting: University gymnasium. Patients or Other Participants: Twenty male (age = 20.83 ± 1.50 years, height = 179.24 ± 7.94 cm, mass = 77.67 ± 10.82 kg) and 20 female (age = 20.45 ± 1.34 years, height = 166.08 ± 5.83 cm, mass = 63.02 ± 6.67 kg) athletes. Intervention(s): We recorded SEBT measurements at baseline, pre-HIIP, and post-HIIP. The HIIP consisted of 4 repetitions of 10-m forward sprinting with a 90° change of direction and then backward sprinting for 5 m, 2 repetitions of 2-legged jumping over 5 hurdles, 2 repetitions of high-knee side stepping over 5 hurdles, and 4 repetitions of lateral 5-m shuffles. Participants rested for 30 seconds before repeating the circuit until they reported a score of 18 on the Borg rating of perceived exertion scale. Main Outcome Measure(s): A mixed between- and within–subjects analysis of variance was conducted to assess time (pre-HIIP, post-HIIP) × sex interaction effects. Subsequent investigations assessed the main effect of time and sex on normalized maximal SEBT scores. We used intraclass correlation coefficients to determine the test-retest reliability of the SEBT and paired-samples t tests to assess the HIIP effect on circuit times. Results: We found a time × sex effect (F8,69 = 3.5; P range, <.001–.04; η2 range, 0.057–0.219), with women less negatively affected. We also noted a main effect for time, with worse normalized maximal SEBT scores postfatigue (F8,69 = 22.39; P < .001; η2 range, 0.324–0.695), and for sex, as

  5. Absolute intensity measurements of the optical second-harmonic response of metals from 0.9 to 2.5 eV

    NASA Astrophysics Data System (ADS)

    Matranga, Christopher; Guyot-Sionnest, Philippe

    2001-11-01

    The absolute intensity of the optical second-harmonic response and its spectral (ωfund≈0.9-2.5 eV) dependence has been measured for Ag(111), polycrystalline Ag, 4-Aminothiophenol/Ag (4-ATP/Ag) and decanethiol/Ag (DT/Ag) surfaces in contact with a liquid electrolyte. Preliminary spectra are also reported for polycrystalline Au and Cu(111) samples. For second-harmonic energies below the plasmon resonance, the magnitude of the nonlinear optical response of clean Ag samples increases as electrode potentials are made more positive. This trend reverses itself for energies above the plasmon resonance. The adsorbate-covered surfaces show a weak or nonexistent potential dependence. A unique feature is found in the 4-ATP/Ag spectra which could possibly be due to a surface charge-transfer state. The Ag results are discussed in the context of a free-electron response from which the spectral and potential dependence of the complex microscopic parameter, a(ω), are extracted. The features in the Au and Cu(111) spectra are not adequately described by this free-electron model and must be related to the effects of interband transitions on the nonlinear optical response.

  6. Do Changes in Tympanic Temperature Predict Changes in Affective Valence during High-Intensity Exercise?

    ERIC Educational Resources Information Center

    Legrand, Fabien D.; Joly, Philippe M.; Bertucci, William M.

    2015-01-01

    Purpose: Increased core (brain or body) temperature that accompanies exercise has been posited to play an influential role in affective responses to exercise. However, findings in support of this hypothesis have been equivocal, and most of the performed studies have been done in relation to anxiety. The aim of the present study was to investigate…

  7. Two percent hypohydration does not impair self-selected high-intensity intermittent exercise performance.

    PubMed

    Yamashita, Naoyuki; Ito, Ryo; Nakano, Masataka; Matsumoto, Takaaki

    2015-01-01

    The level of hypohydration at which power output during intermittent exercise performance starts to decrease is not fully understood. The purpose of this study was to investigate the effects of 2% hypohydration without hyperthermia on intermittent exercise performance. Eight collegiate amateur boxers completed 2 exercise tests. On day 1, subjects hypohydrated by 2% of body mass by exercising in a hot environment, and on day 2, subjects performed intermittent exercise (4 × 2 minute per round [R] separated by 1-minute recovery) under a randomly assigned condition of with (HYP) or without (EUH) hypohydration. Each bout consisted of 8 × 5 seconds of maximal cycling exercise (0.05 kp × body mass) separated by 10 seconds of passive recovery. Mean power output per kilogram (MPO), total power output per kilogram (TPO), energy system relative contribution, and core rectal temperature (Tre) were measured. Changes in body mass before the exercise tests were -2.25 ± 0.18% (HYP) and -0.17 ± 0.19% (EUH) (p < 0.001). Mean power output, TPO, and each energy contribution ratio were not significantly different between the trials, and pre- and postexercise test Tre did not differ significantly between trials. Results demonstrated that approximately 2% hypohydration lies below the point at which power output during intermittent exercise starts to decline.

  8. Expiratory muscle fatigue does not regulate operating lung volumes during high-intensity exercise in healthy humans.

    PubMed

    Taylor, Bryan J; How, Stephen C; Romer, Lee M

    2013-06-01

    To determine whether expiratory muscle fatigue (EMF) is involved in regulating operating lung volumes during exercise, nine recreationally active subjects cycled at 90% of peak work rate to the limit of tolerance with prior induction of EMF (EMF-ex) and for a time equal to that achieved in EMF-ex without prior induction of EMF (ISO-ex). EMF was assessed by measuring changes in magnetically evoked gastric twitch pressure. Changes in end-expiratory and end-inspiratory lung volume (EELV and EILV) and the degree of expiratory flow limitation (EFL) were quantified using maximal expiratory flow-volume curves and inspiratory capacity maneuvers. Resistive breathing reduced gastric twitch pressure (-24 ± 14%, P = 0.004). During EMF-ex, EELV decreased from rest to the 3rd min of exercise [39 ± 8 vs. 27 ± 7% of forced vital capacity (FVC), P = 0.001] before increasing toward baseline (34 ± 8% of FVC end exercise, P = 0.073 vs. rest). EILV increased from rest to the 3rd min of exercise (54 ± 8 vs. 84 ± 9% of FVC, P = 0.006) and remained elevated to end exercise (88 ± 9% of FVC). Neither EELV (P = 0.18) nor EILV (P = 0.26) was different at any time point during EMF-ex vs. ISO-ex. Four subjects became expiratory flow limited during the final minute of EMF-ex and ISO-ex; the degree of EFL was not different between trials (37 ± 18 vs. 35 ± 16% of tidal volume, P = 0.38). At end exercise in both trials, EELV was greater in subjects without vs. subjects with EFL. These findings suggest that 1) contractile fatigue of the expiratory muscles in healthy humans does not regulate operating lung volumes during high-intensity sustained cycle exercise; and 2) factors other than "frank" EFL cause the terminal increase in EELV.

  9. The roles of catecholamines in glucoregulation in intense exercise as defined by the islet cell clamp technique.

    PubMed

    Sigal, R J; Fisher, S; Halter, J B; Vranic, M; Marliss, E B

    1996-02-01

    Exercise at > 85% VO2max causes the greatest known physiological increases in glucose production rates (Ra). To define the relative roles of catecholamine versus glucagon/insulin responses in stimulating Ra, normal subjects in the postabsorptive state exercised at 87 +/- 2% VO2max during an islet cell clamp (IC): intravenous octreotide (somatostatin analog), 30 ng.kg-1.min-1; glucagon, 0.8 ng.kg-1.min-1; growth hormone, 10 ng.kg-1.min-1; and insulin adjusted to achieve euglycemia, then constant 56 +/- 7 min before exercise. Seven control subjects exercised without an IC. In four subjects (IC-1) with hormone infusions held constant during exercise, plasma insulin rose 76% and glucagon 35%, perhaps because of altered hemodynamics. In seven subjects (IC-2), hormone infusions were decreased stepwise during exercise and returned stepwise to initial rates during early recovery. Ra increased sixfold in control and both IC groups. Plasma norepinephrine and epinephrine likewise increased > 12-fold with no differences among groups; both catecholamines correlated closely with Ra. Because mixed venous blood plasma insulin declined and glucagon did not change in control subjects, the glucagon-to-insulin ratio increased from 0.20 to 0.26 (P = 0.02). In IC subjects, plasma insulin increased and glucagon was either constant (IC-2) or increased less than insulin, resulting in nonsignificant declines in the immunoreactive glucose-to-immunoreactive insulin ratio. Although a rise in insulin would have been expected to attenuate the Ra increment, this effect was overridden. The strong correlations of Ra with catecholamines and the similar Ra responses despite divergent glucagon-to-insulin responses are consistent with the primacy of catecholamines in regulation of Ra in intense exercise.

  10. Changes in mechanisms proposed to mediate fat loss following an acute bout of high-intensity interval and endurance exercise.

    PubMed

    Williams, Cameron B; Zelt, Jason G E; Castellani, Laura N; Little, Jonathan P; Jung, Mary E; Wright, David C; Tschakovsky, Michael E; Gurd, Brendon J

    2013-12-01

    The purpose of this study was to investigate the acute effects of endurance exercise (END; 65% V̇O2peak for 60 min) and high-intensity interval exercise (HIE; four 30 s Wingates separated by 4.5 min of active rest) on cardiorespiratory, hormonal, and subjective appetite measures that may account for the previously reported superior fat loss with low volume HIE compared with END. Recreationally active males (n = 18) completed END, HIE, and control (CON) protocols. On each test day, cardiorespiratory measures including oxygen uptake (V̇O2), respiratory exchange ratio (RER), and heart rate were recorded and blood samples were obtained at baseline (BSL), 60 min after exercise, and 180 min after exercise (equivalent times for CON). Subjective measures of appetite (hunger, fullness, nausea, and prospective consumption) were assessed using visual analogue scales, administered at BSL, 0, 60, 120, and 180 min after exercise. No significant differences in excess postexercise oxygen consumption (EPOC) were observed between conditions. RER was significantly (P < 0.05) depressed in HIE compared with CON at 60 min after exercise, yet estimates of total fat oxidation over CON were not different between HIE and END. No differences in plasma adiponectin concentrations between protocols or time points were present. Epinephrine and norepinephrine were significantly (P < 0.05) elevated immediately after exercise in HIE compared with CON. Several subjective measures of appetite were significantly (P < 0.05) depressed immediately following HIE. Our data indicate that increases in EPOC or fat oxidation following HIE appear unlikely to contribute to the reported superior fat loss compared with END.

  11. Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise.

    PubMed

    Place, Nicolas; Ivarsson, Niklas; Venckunas, Tomas; Neyroud, Daria; Brazaitis, Marius; Cheng, Arthur J; Ochala, Julien; Kamandulis, Sigitas; Girard, Sebastien; Volungevičius, Gintautas; Paužas, Henrikas; Mekideche, Abdelhafid; Kayser, Bengt; Martinez-Redondo, Vicente; Ruas, Jorge L; Bruton, Joseph; Truffert, Andre; Lanner, Johanna T; Skurvydas, Albertas; Westerblad, Håkan

    2015-12-15

    High-intensity interval training (HIIT) is a time-efficient way of improving physical performance in healthy subjects and in patients with common chronic diseases, but less so in elite endurance athletes. The mechanisms underlying the effectiveness of HIIT are uncertain. Here, recreationally active human subjects performed highly demanding HIIT consisting of 30-s bouts of all-out cycling with 4-min rest in between bouts (≤3 min total exercise time). Skeletal muscle biopsies taken 24 h after the HIIT exercise showed an extensive fragmentation of the sarcoplasmic reticulum (SR) Ca(2+) release channel, the ryanodine receptor type 1 (RyR1). The HIIT exercise also caused a prolonged force depression and triggered major changes in the expression of genes related to endurance exercise. Subsequent experiments on elite endurance athletes performing the same HIIT exercise showed no RyR1 fragmentation or prolonged changes in the expression of endurance-related genes. Finally, mechanistic experiments performed on isolated mouse muscles exposed to HIIT-mimicking stimulation showed reactive oxygen/nitrogen species (ROS)-dependent RyR1 fragmentation, calpain activation, increased SR Ca(2+) leak at rest, and depressed force production due to impaired SR Ca(2+) release upon stimulation. In conclusion, HIIT exercise induces a ROS-dependent RyR1 fragmentation in muscles of recreationally active subjects, and the resulting changes in muscle fiber Ca(2+)-handling trigger muscular adaptations. However, the same HIIT exercise does not cause RyR1 fragmentation in muscles of elite endurance athletes, which may explain why HIIT is less effective in this group.

  12. Expiratory muscle fatigue does not regulate operating lung volumes during high-intensity exercise in healthy humans.

    PubMed

    Taylor, Bryan J; How, Stephen C; Romer, Lee M

    2013-06-01

    To determine whether expiratory muscle fatigue (EMF) is involved in regulating operating lung volumes during exercise, nine recreationally active subjects cycled at 90% of peak work rate to the limit of tolerance with prior induction of EMF (EMF-ex) and for a time equal to that achieved in EMF-ex without prior induction of EMF (ISO-ex). EMF was assessed by measuring changes in magnetically evoked gastric twitch pressure. Changes in end-expiratory and end-inspiratory lung volume (EELV and EILV) and the degree of expiratory flow limitation (EFL) were quantified using maximal expiratory flow-volume curves and inspiratory capacity maneuvers. Resistive breathing reduced gastric twitch pressure (-24 ± 14%, P = 0.004). During EMF-ex, EELV decreased from rest to the 3rd min of exercise [39 ± 8 vs. 27 ± 7% of forced vital capacity (FVC), P = 0.001] before increasing toward baseline (34 ± 8% of FVC end exercise, P = 0.073 vs. rest). EILV increased from rest to the 3rd min of exercise (54 ± 8 vs. 84 ± 9% of FVC, P = 0.006) and remained elevated to end exercise (88 ± 9% of FVC). Neither EELV (P = 0.18) nor EILV (P = 0.26) was different at any time point during EMF-ex vs. ISO-ex. Four subjects became expiratory flow limited during the final minute of EMF-ex and ISO-ex; the degree of EFL was not different between trials (37 ± 18 vs. 35 ± 16% of tidal volume, P = 0.38). At end exercise in both trials, EELV was greater in subjects without vs. subjects with EFL. These findings suggest that 1) contractile fatigue of the expiratory muscles in healthy humans does not regulate operating lung volumes during high-intensity sustained cycle exercise; and 2) factors other than "frank" EFL cause the terminal increase in EELV. PMID:23558390

  13. Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise.

    PubMed

    Place, Nicolas; Ivarsson, Niklas; Venckunas, Tomas; Neyroud, Daria; Brazaitis, Marius; Cheng, Arthur J; Ochala, Julien; Kamandulis, Sigitas; Girard, Sebastien; Volungevičius, Gintautas; Paužas, Henrikas; Mekideche, Abdelhafid; Kayser, Bengt; Martinez-Redondo, Vicente; Ruas, Jorge L; Bruton, Joseph; Truffert, Andre; Lanner, Johanna T; Skurvydas, Albertas; Westerblad, Håkan

    2015-12-15

    High-intensity interval training (HIIT) is a time-efficient way of improving physical performance in healthy subjects and in patients with common chronic diseases, but less so in elite endurance athletes. The mechanisms underlying the effectiveness of HIIT are uncertain. Here, recreationally active human subjects performed highly demanding HIIT consisting of 30-s bouts of all-out cycling with 4-min rest in between bouts (≤3 min total exercise time). Skeletal muscle biopsies taken 24 h after the HIIT exercise showed an extensive fragmentation of the sarcoplasmic reticulum (SR) Ca(2+) release channel, the ryanodine receptor type 1 (RyR1). The HIIT exercise also caused a prolonged force depression and triggered major changes in the expression of genes related to endurance exercise. Subsequent experiments on elite endurance athletes performing the same HIIT exercise showed no RyR1 fragmentation or prolonged changes in the expression of endurance-related genes. Finally, mechanistic experiments performed on isolated mouse muscles exposed to HIIT-mimicking stimulation showed reactive oxygen/nitrogen species (ROS)-dependent RyR1 fragmentation, calpain activation, increased SR Ca(2+) leak at rest, and depressed force production due to impaired SR Ca(2+) release upon stimulation. In conclusion, HIIT exercise induces a ROS-dependent RyR1 fragmentation in muscles of recreationally active subjects, and the resulting changes in muscle fiber Ca(2+)-handling trigger muscular adaptations. However, the same HIIT exercise does not cause RyR1 fragmentation in muscles of elite endurance athletes, which may explain why HIIT is less effective in this group. PMID:26575622

  14. Efficacy of acute caffeine ingestion for short-term high-intensity exercise performance: a systematic review.

    PubMed

    Astorino, Todd A; Roberson, Daniel W

    2010-01-01

    Caffeine is the most widely used drug in the world, commonly ingested in coffee, tea, soda, and energy drinks. Its ability to enhance muscular work has been apparent since the early 1900s. Caffeine typically increases endurance performance; however, efficacy of caffeine ingestion for short-term high-intensity exercise is equivocal, which may be explained by discrepancies in exercise protocols, dosing, and subjects' training status and habitual caffeine intake found across studies. The primary aim of this review is to critically examine studies that have tested caffeine's ability to augment performance during exercise dependent on nonoxidative metabolism such as sprinting, team sports, and resistance training. A review of the literature revealed 29 studies that measured alterations in short-term performance after caffeine ingestion. Each study was critically analyzed using the Physiotherapy Evidence Database (PEDro) scale. The mean PEDro score was 7.76 +/- 0.87. Eleven of 17 studies revealed significant improvements in team sports exercise and power-based sports with caffeine ingestion, yet these effects were more common in elite athletes who do not regularly ingest caffeine. Six of 11 studies revealed significant benefits of caffeine for resistance training. Some studies show decreased performance with caffeine ingestion when repeated bouts are completed. The exact mechanism explaining the ergogenic effect of caffeine for short-term exercise is unknown.

  15. Efficacy of acute caffeine ingestion for short-term high-intensity exercise performance: a systematic review.

    PubMed

    Astorino, Todd A; Roberson, Daniel W

    2010-01-01

    Caffeine is the most widely used drug in the world, commonly ingested in coffee, tea, soda, and energy drinks. Its ability to enhance muscular work has been apparent since the early 1900s. Caffeine typically increases endurance performance; however, efficacy of caffeine ingestion for short-term high-intensity exercise is equivocal, which may be explained by discrepancies in exercise protocols, dosing, and subjects' training status and habitual caffeine intake found across studies. The primary aim of this review is to critically examine studies that have tested caffeine's ability to augment performance during exercise dependent on nonoxidative metabolism such as sprinting, team sports, and resistance training. A review of the literature revealed 29 studies that measured alterations in short-term performance after caffeine ingestion. Each study was critically analyzed using the Physiotherapy Evidence Database (PEDro) scale. The mean PEDro score was 7.76 +/- 0.87. Eleven of 17 studies revealed significant improvements in team sports exercise and power-based sports with caffeine ingestion, yet these effects were more common in elite athletes who do not regularly ingest caffeine. Six of 11 studies revealed significant benefits of caffeine for resistance training. Some studies show decreased performance with caffeine ingestion when repeated bouts are completed. The exact mechanism explaining the ergogenic effect of caffeine for short-term exercise is unknown. PMID:19924012

  16. Role of self-reported individual differences in preference for and tolerance of exercise intensity in fitness testing performance.

    PubMed

    Hall, Eric E; Petruzzello, Steven J; Ekkekakis, Panteleimon; Miller, Paul C; Bixby, Walter R

    2014-09-01

    Performance in fitness tests could depend on factors beyond the bioenergetic and skeletomuscular systems, such as individual differences in preference for and tolerance of different levels of exercise-induced somatosensory stimulation. Although such individual-difference variables could play a role in exercise testing and prescription, they have been understudied. The purpose of these studies was to examine the relationships of self-reported preference for and tolerance of exercise intensity with performance in fitness tests. Participants in study I were 516 men and women volunteers from a campus community, and participants in study II were 42 men recruit firefighters undergoing a 6-week training program. Both the Preference and Tolerance scores exhibited significant relationships with performance in several fitness tests and with body composition and physical activity participation. Preference and Tolerance did not change after the training program in study II, despite improvements in objective and perceived fitness, supporting their conceptualization as dispositional traits. Preference and Tolerance scores could be useful not only in ameliorating the current understanding of the determinants of physical performance, but also in personalizing exercise prescriptions and, thus, delivering exercise experiences that are more pleasant, tolerable, and sustainable.

  17. Effect of Locomotor Respiratory Coupling Induced by Cortical Oxygenated Hemoglobin Levels During Cycle Ergometer Exercise of Light Intensity.

    PubMed

    Oyanagi, Keiichi; Tsubaki, Atsuhiro; Yasufuku, Yuichi; Takai, Haruna; Kera, Takeshi; Tamaki, Akira; Iwata, Kentaro; Onishi, Hideaki

    2016-01-01

    This study aimed to clarify the effects of locomotor-respiratory coupling (LRC) induced by light load cycle ergometer exercise on oxygenated hemoglobin (O2Hb) in the dorsolateral prefrontal cortex (DLPFC), supplementary motor area (SMA), and sensorimotor cortex (SMC). The participants were 15 young healthy adults (9 men and 6 women, mean age: 23.1 ± 1.8 (SEM) years). We conducted a task in both LRC-inducing and LRC-non-inducing conditions for all participants. O2Hb was measured using near-infrared spectroscopy. The LRC frequency ratio during induction was 2:1; pedaling rate, 50 rpm; and intensity of load, 30 % peak volume of oxygen uptake. The test protocol included a 3-min rest prior to exercise, steady loading motion for 10 min, and 10-min rest post exercise (a total of 23 min). In the measurement of O2Hb, we focused on the DLPFC, SMA, and SMC. The LRC frequency was significantly higher in the LRC-inducing condition (p < 0.05). O2Hb during exercise was significantly lower in the DLPFC and SMA, under the LRC-inducing condition (p < 0.05). The study revealed that even light load could induce LRC and that O2Hb in the DLPFC and SMA decreases during exercise via LRC induction.

  18. Lymphocyte Redox Imbalance and Reduced Proliferation after a Single Session of High Intensity Interval Exercise.

    PubMed

    Tossige-Gomes, Rosalina; Costa, Karine Beatriz; Ottone, Vinícius de Oliveira; Magalhães, Flávio de Castro; Amorim, Fabiano Trigueiro; Rocha-Vieira, Etel

    2016-01-01

    This study investigated whether an acute session of high-intensity interval training (HIIT) is sufficient to alter lymphocyte function and redox status. Sixteen young healthy men underwent a HIIT session on a cycloergometer, consisting of eight bouts of 1 min at 90-100% of peak power, with 75 seconds of active recovery at 30 W between bouts. Venous blood was collected before, immediately after, and 30 minutes after the HIIT session. In response to Staphylococcus aureus superantigen B (SEB) stimulation, lymphocyte proliferation decreased and the IL-2 concentration increased after the HIIT session. However, the HIIT session had no effect on lymphocyte proliferation or IL-2 response to phytohemagglutinin stimulation. The HIIT session also induced lymphocyte redox imbalance, characterized by an increase in the concentration of thiobarbituric acid reactive substances and a decrease in the activity of the antioxidant enzyme catalase. Lymphocyte viability was not affected by the HIIT session. The frequencies of CD25+ and CD69+ T helper and B lymphocytes in response to superantigen stimulation were lower after exercise, suggesting that superantigen-induced lymphocyte activation was reduced by HIIT. However, HIIT also led to a reduction in the frequency of CD4+ and CD19+ cells, so the frequencies of CD25+ and CD69+ cells within the CD4 and CD19 cell populations were not affected by HIIT. These data indicate that the reduced lymphocyte proliferation observed after HIIT is not due to reduced early lymphocyte activation by superantigen. Our findings show that an acute HIIT session promotes lymphocyte redox imbalance and reduces lymphocyte proliferation in response to superantigenic, but not to mitogenic stimulation. This observation cannot be explained by alteration of the early lymphocyte activation response to superantigen. The manner in which lymphocyte function modulation by an acute HIIT session can affect individual immunity and susceptibility to infection is important

  19. Lymphocyte Redox Imbalance and Reduced Proliferation after a Single Session of High Intensity Interval Exercise

    PubMed Central

    Tossige-Gomes, Rosalina; Costa, Karine Beatriz; Ottone, Vinícius de Oliveira; Magalhães, Flávio de Castro; Amorim, Fabiano Trigueiro; Rocha-Vieira, Etel

    2016-01-01

    This study investigated whether an acute session of high-intensity interval training (HIIT) is sufficient to alter lymphocyte function and redox status. Sixteen young healthy men underwent a HIIT session on a cycloergometer, consisting of eight bouts of 1 min at 90–100% of peak power, with 75 seconds of active recovery at 30 W between bouts. Venous blood was collected before, immediately after, and 30 minutes after the HIIT session. In response to Staphylococcus aureus superantigen B (SEB) stimulation, lymphocyte proliferation decreased and the IL-2 concentration increased after the HIIT session. However, the HIIT session had no effect on lymphocyte proliferation or IL-2 response to phytohemagglutinin stimulation. The HIIT session also induced lymphocyte redox imbalance, characterized by an increase in the concentration of thiobarbituric acid reactive substances and a decrease in the activity of the antioxidant enzyme catalase. Lymphocyte viability was not affected by the HIIT session. The frequencies of CD25+ and CD69+ T helper and B lymphocytes in response to superantigen stimulation were lower after exercise, suggesting that superantigen-induced lymphocyte activation was reduced by HIIT. However, HIIT also led to a reduction in the frequency of CD4+ and CD19+ cells, so the frequencies of CD25+ and CD69+ cells within the CD4 and CD19 cell populations were not affected by HIIT. These data indicate that the reduced lymphocyte proliferation observed after HIIT is not due to reduced early lymphocyte activation by superantigen. Our findings show that an acute HIIT session promotes lymphocyte redox imbalance and reduces lymphocyte proliferation in response to superantigenic, but not to mitogenic stimulation. This observation cannot be explained by alteration of the early lymphocyte activation response to superantigen. The manner in which lymphocyte function modulation by an acute HIIT session can affect individual immunity and susceptibility to infection is important

  20. Lymphocyte Redox Imbalance and Reduced Proliferation after a Single Session of High Intensity Interval Exercise.

    PubMed

    Tossige-Gomes, Rosalina; Costa, Karine Beatriz; Ottone, Vinícius de Oliveira; Magalhães, Flávio de Castro; Amorim, Fabiano Trigueiro; Rocha-Vieira, Etel

    2016-01-01

    This study investigated whether an acute session of high-intensity interval training (HIIT) is sufficient to alter lymphocyte function and redox status. Sixteen young healthy men underwent a HIIT session on a cycloergometer, consisting of eight bouts of 1 min at 90-100% of peak power, with 75 seconds of active recovery at 30 W between bouts. Venous blood was collected before, immediately after, and 30 minutes after the HIIT session. In response to Staphylococcus aureus superantigen B (SEB) stimulation, lymphocyte proliferation decreased and the IL-2 concentration increased after the HIIT session. However, the HIIT session had no effect on lymphocyte proliferation or IL-2 response to phytohemagglutinin stimulation. The HIIT session also induced lymphocyte redox imbalance, characterized by an increase in the concentration of thiobarbituric acid reactive substances and a decrease in the activity of the antioxidant enzyme catalase. Lymphocyte viability was not affected by the HIIT session. The frequencies of CD25+ and CD69+ T helper and B lymphocytes in response to superantigen stimulation were lower after exercise, suggesting that superantigen-induced lymphocyte activation was reduced by HIIT. However, HIIT also led to a reduction in the frequency of CD4+ and CD19+ cells, so the frequencies of CD25+ and CD69+ cells within the CD4 and CD19 cell populations were not affected by HIIT. These data indicate that the reduced lymphocyte proliferation observed after HIIT is not due to reduced early lymphocyte activation by superantigen. Our findings show that an acute HIIT session promotes lymphocyte redox imbalance and reduces lymphocyte proliferation in response to superantigenic, but not to mitogenic stimulation. This observation cannot be explained by alteration of the early lymphocyte activation response to superantigen. The manner in which lymphocyte function modulation by an acute HIIT session can affect individual immunity and susceptibility to infection is important

  1. Is performance of intermittent intense exercise enhanced by use of a commercial palm cooling device?

    PubMed

    Walker, Thomas B; Zupan, Michael F; McGregor, Julia N; Cantwell, Andrew R; Norris, Torrance D

    2009-12-01

    The purpose of this study was to determine if using the CoreControl Rapid Thermal Exchange (RTX), a commercial palm cooling device, during active rest periods of multiple set training is an effective means to increase performance. Ten volunteers (5 men, 5 women) completed a VO2max test on a motorized treadmill and 3 interval running tests on a human powered treadmill. This treadmill allowed the subjects to quickly reach their running speed while allowing for measurement of distance, speed, and force. During the interval running tests the subjects completed eight 30-second intervals at a hard/fast pace followed by a 90-second walking or light jogging recovery period. During the recovery period, the subjects placed their left hand on 1 of 3 media: the RTX held at 15 degrees C (R), a 15 degrees C standard refrigerant gel pack (P), or nothing at all (C). Although there were differences in core temperature (Tc), subjective heat stress ratings, distance, and power generated between intervals, there were no significant differences (p < 0.05) found between treatments for any of these variables, nor was the interaction effect of interval*treatment found to be significant. Mean distance completed per trial was 717.1 m +/- 124.4 m (R), 724.8 m +/- 130.3 m (P), and 728.6 m +/- 110.6 m (C). Change in Tc from baseline to end-test averaged 1.41 degrees C +/- 0.37 degrees C (R), 1.41 degrees C +/- 0.39 degrees C (P), and 1.41 degrees C +/- 0.59 degrees C (C). There were no significant differences (p < 0.05) in Tc, heart rate (HR), or VO2 between intervals or treatments. We conclude that the RTX, in its current iteration, is ineffective at improving performance and/or mitigating thermal stress during high-intensity intermittent exercise. PMID:19910808

  2. High-intensity Exercise Modifies the Effects of Stanozolol on Brain Oxidative Stress in Rats.

    PubMed

    Camiletti-Moirón, D; Aparicio, V A; Nebot, E; Medina, G; Martínez, R; Kapravelou, G; Andrade, A; Porres, J M; López-Jurado, M; Aranda, P

    2015-11-01

    We analyzed the effects of high-intensity exercise (HIE) and anabolic androgenic steroids (AAS) on brain redox status. 40 male Wistar rats were randomly distributed in 4 experimental groups (n=10) with or without HIE and with or without weekly Stanozolol administration. Thiobarbituric acid-reactive substances (TBARs) and protein carbonyl content (PCC) were assessed. Total superoxide dismutase (tSOD), manganese superoxide dismutase (Mn-SOD), copper/zinc superoxide dismutase (CuZn-SOD) and catalase (CAT) activities were measured. Finally, protein expression levels of glutathione peroxidase (GPx), NAD(P)H dehydrogenase, Quinone 1 (NQO1), NF-E2-Related Factor 2 (Nrf2), glial fibrillary acidic protein (GFAP), nuclear factor kappa β p65 (NF-κβ) and signal transducer and activator of transcription 3 were determined. Brain PCC concentrations were lower in the HIE groups compared to the untrained controls, whereas CAT activity was higher (both, p<0.01). Both HIE and AAS groups exhibited higher expression levels of GFAP and GPx, but lower NQO1 levels (all, p<0.05). There were increased expression levels of NF-κβ in the AAS groups (p<0.01). In addition, there was increased expression of Nrf2 in the HIE groups (p<0.001). HIE*AAS interactions were found on TBARs content and GFAP expression, with HIE downregulating and upregulating AAS-mediated increases in TBARs and GFAP, respectively (p<0.05). Overall, HIE appeared to reduce the AAS-mediated negative effect on brain redox status. PMID:26252547

  3. High-intensity Exercise Modifies the Effects of Stanozolol on Brain Oxidative Stress in Rats.

    PubMed

    Camiletti-Moirón, D; Aparicio, V A; Nebot, E; Medina, G; Martínez, R; Kapravelou, G; Andrade, A; Porres, J M; López-Jurado, M; Aranda, P

    2015-11-01

    We analyzed the effects of high-intensity exercise (HIE) and anabolic androgenic steroids (AAS) on brain redox status. 40 male Wistar rats were randomly distributed in 4 experimental groups (n=10) with or without HIE and with or without weekly Stanozolol administration. Thiobarbituric acid-reactive substances (TBARs) and protein carbonyl content (PCC) were assessed. Total superoxide dismutase (tSOD), manganese superoxide dismutase (Mn-SOD), copper/zinc superoxide dismutase (CuZn-SOD) and catalase (CAT) activities were measured. Finally, protein expression levels of glutathione peroxidase (GPx), NAD(P)H dehydrogenase, Quinone 1 (NQO1), NF-E2-Related Factor 2 (Nrf2), glial fibrillary acidic protein (GFAP), nuclear factor kappa β p65 (NF-κβ) and signal transducer and activator of transcription 3 were determined. Brain PCC concentrations were lower in the HIE groups compared to the untrained controls, whereas CAT activity was higher (both, p<0.01). Both HIE and AAS groups exhibited higher expression levels of GFAP and GPx, but lower NQO1 levels (all, p<0.05). There were increased expression levels of NF-κβ in the AAS groups (p<0.01). In addition, there was increased expression of Nrf2 in the HIE groups (p<0.001). HIE*AAS interactions were found on TBARs content and GFAP expression, with HIE downregulating and upregulating AAS-mediated increases in TBARs and GFAP, respectively (p<0.05). Overall, HIE appeared to reduce the AAS-mediated negative effect on brain redox status.

  4. Effect of hypoxia on cerebrovascular and cognitive function during moderate intensity exercise.

    PubMed

    Lefferts, Wesley K; Babcock, Matthew C; Tiss, Matthew J; Ives, Stephen J; White, Corey N; Brutsaert, Tom D; Heffernan, Kevin S

    2016-10-15

    Exercise in hypoxia places added demands on the brain and cerebrovasculature that can impact cognitive function. The purpose of this study was to investigate the effect of acute hypoxia on cerebrovascular hemodynamics, markers of neuro-steroidal modulation and brain-blood barrier (BBB) integrity, and cognition during exercise. Thirty healthy participants (21±4yrs., BMI 24.0±2.6kg∙m(-2); 15 men) were randomized to both a≈2.5h normoxic (FiO2 20.0%) and hypoxic (FiO2 12.5%) condition on two separate days. After 1.25h, participants underwent 10min of exercise-alone (cycling at 55% HRmax) and 15min of exercise+cognitive testing. Prefrontal cortex (PFC) tissue oxygenation and middle cerebral artery (MCA) mean blood velocity (MnV) were measured using near-infrared spectroscopy and transcranial Doppler respectively at rest, during exercise-alone, and during exercise+cognitive testing. Salivary levels of dehydroepiandosterone [DHEA], DHEA-sulfate [DHEAS]) and neuron specific enolase (NSE) were measured pre and post exercise. Cognition was assessed using standard metrics of accuracy and reaction time (RT), and advanced metrics from drift-diffusion modeling across memory recognition, N-Back and Flanker tasks. MCA MnV increased from rest to exercise (p<0.01) and was unchanged with addition of cognitive testing during exercise in both normoxia and hypoxia. PFC oxygenation increased during exercise (p<0.05) and was further increased with addition of cognitive challenge in normoxia but decreased during exercise in hypoxia (p<0.05) with further reductions occurring with addition of cognitive tasks (p<0.05). DHEA and NSE increased and decreased post-exercise, respectively, in both normoxia and hypoxia (p<0.01). Accuracy on cognitive tasks was similar in normoxia compared to hypoxia, while RT was slower in hypoxia vs normoxia across memory recognition (p<0.01) and Flanker tasks (p=0.04). Drift-diffusion modeling suggested changes in memory RT were due to increases in caution

  5. Effect of hypoxia on cerebrovascular and cognitive function during moderate intensity exercise.

    PubMed

    Lefferts, Wesley K; Babcock, Matthew C; Tiss, Matthew J; Ives, Stephen J; White, Corey N; Brutsaert, Tom D; Heffernan, Kevin S

    2016-10-15

    Exercise in hypoxia places added demands on the brain and cerebrovasculature that can impact cognitive function. The purpose of this study was to investigate the effect of acute hypoxia on cerebrovascular hemodynamics, markers of neuro-steroidal modulation and brain-blood barrier (BBB) integrity, and cognition during exercise. Thirty healthy participants (21±4yrs., BMI 24.0±2.6kg∙m(-2); 15 men) were randomized to both a≈2.5h normoxic (FiO2 20.0%) and hypoxic (FiO2 12.5%) condition on two separate days. After 1.25h, participants underwent 10min of exercise-alone (cycling at 55% HRmax) and 15min of exercise+cognitive testing. Prefrontal cortex (PFC) tissue oxygenation and middle cerebral artery (MCA) mean blood velocity (MnV) were measured using near-infrared spectroscopy and transcranial Doppler respectively at rest, during exercise-alone, and during exercise+cognitive testing. Salivary levels of dehydroepiandosterone [DHEA], DHEA-sulfate [DHEAS]) and neuron specific enolase (NSE) were measured pre and post exercise. Cognition was assessed using standard metrics of accuracy and reaction time (RT), and advanced metrics from drift-diffusion modeling across memory recognition, N-Back and Flanker tasks. MCA MnV increased from rest to exercise (p<0.01) and was unchanged with addition of cognitive testing during exercise in both normoxia and hypoxia. PFC oxygenation increased during exercise (p<0.05) and was further increased with addition of cognitive challenge in normoxia but decreased during exercise in hypoxia (p<0.05) with further reductions occurring with addition of cognitive tasks (p<0.05). DHEA and NSE increased and decreased post-exercise, respectively, in both normoxia and hypoxia (p<0.01). Accuracy on cognitive tasks was similar in normoxia compared to hypoxia, while RT was slower in hypoxia vs normoxia across memory recognition (p<0.01) and Flanker tasks (p=0.04). Drift-diffusion modeling suggested changes in memory RT were due to increases in caution

  6. Acute Physiological Responses to Short- and Long-Stage High-Intensity Interval Exercise in Cardiac Rehabilitation: A Pilot Study.

    PubMed

    Tschakert, Gerhard; Kroepfl, Julia M; Mueller, Alexander; Harpf, Hanns; Harpf, Leonhard; Traninger, Heimo; Wallner-Liebmann, Sandra; Stojakovic, Tatjana; Scharnagl, Hubert; Meinitzer, Andreas; Pichlhoefer, Patriz; Hofmann, Peter

    2016-03-01

    Despite described benefits of aerobic high-intensity interval exercise (HIIE), the acute responses during different HIIE modes and associated health risks have only been sparsely discovered in heart disease patients. Therefore, the aim of this study was to investigate the acute responses for physiological parameters, cardiovascular and inflammatory biomarkers, and catecholamines yielded by two different aerobic HIIE protocols compared to continuous exercise (CE) in phase III cardiac rehabilitation. Eight cardiac patients (7 with coronary heart disease, 1 with myocarditis; 7 males, 1 female; age: 63.0 ± 9.4 years; height: 1.74 ± 0.05 m; weight: 83.6 ± 8.7 kg), all but one treated with ß-blocking agents, performed a maximal symptom-limited incremental exercise test (IET) and three different exercise tests matched for mean load (Pmean) and total duration: 1) short HIIE with a peak workload duration (tpeak) of 20 s and a peak workload (Ppeak) equal to the maximum power output (Pmax) from IET; 2) long HIIE with a tpeak of 4 min, Ppeak was corresponding to the power output at 85 % of maximal heart rate (HRmax) from IET; 3) CE with a target workload equal to Pmean of both HIIE modes. Acute metabolic and peak cardiorespiratory responses were significantly higher during long HIIE compared to short HIIE and CE (p < 0.05) except HRpeak which tended to be higher in long HIIE than in short HIIE (p = 0.08). Between short HIIE and CE, no significant difference was found for any parameter. Acute responses of cardiovascular and inflammatory biomarkers and catecholamines didn't show any significant difference between tests (p > 0.05). All health-related variables remained in a normal range in any test except NT-proBNP, which was already elevated at baseline. Despite a high Ppeak particularly in short HIIE, both HIIE modes were as safe and as well tolerated as moderate CE in cardiac patients by using our methodological approach. Key pointsHigh-intensity interval exercise (HIIE

  7. Acute Physiological Responses to Short- and Long-Stage High-Intensity Interval Exercise in Cardiac Rehabilitation: A Pilot Study

    PubMed Central

    Tschakert, Gerhard; Kroepfl, Julia M.; Mueller, Alexander; Harpf, Hanns; Harpf, Leonhard; Traninger, Heimo; Wallner-Liebmann, Sandra; Stojakovic, Tatjana; Scharnagl, Hubert; Meinitzer, Andreas; Pichlhoefer, Patriz; Hofmann, Peter

    2016-01-01

    Despite described benefits of aerobic high-intensity interval exercise (HIIE), the acute responses during different HIIE modes and associated health risks have only been sparsely discovered in heart disease patients. Therefore, the aim of this study was to investigate the acute responses for physiological parameters, cardiovascular and inflammatory biomarkers, and catecholamines yielded by two different aerobic HIIE protocols compared to continuous exercise (CE) in phase III cardiac rehabilitation. Eight cardiac patients (7 with coronary heart disease, 1 with myocarditis; 7 males, 1 female; age: 63.0 ± 9.4 years; height: 1.74 ± 0.05 m; weight: 83.6 ± 8.7 kg), all but one treated with ß-blocking agents, performed a maximal symptom-limited incremental exercise test (IET) and three different exercise tests matched for mean load (Pmean) and total duration: 1) short HIIE with a peak workload duration (tpeak) of 20 s and a peak workload (Ppeak) equal to the maximum power output (Pmax) from IET; 2) long HIIE with a tpeak of 4 min, Ppeak was corresponding to the power output at 85 % of maximal heart rate (HRmax) from IET; 3) CE with a target workload equal to Pmean of both HIIE modes. Acute metabolic and peak cardiorespiratory responses were significantly higher during long HIIE compared to short HIIE and CE (p < 0.05) except HRpeak which tended to be higher in long HIIE than in short HIIE (p = 0.08). Between short HIIE and CE, no significant difference was found for any parameter. Acute responses of cardiovascular and inflammatory biomarkers and catecholamines didn’t show any significant difference between tests (p > 0.05). All health-related variables remained in a normal range in any test except NT-proBNP, which was already elevated at baseline. Despite a high Ppeak particularly in short HIIE, both HIIE modes were as safe and as well tolerated as moderate CE in cardiac patients by using our methodological approach. Key points High-intensity interval exercise (HIIE

  8. Exercise

    MedlinePlus

    ... article Exercise / physical activity with MS Judy Boone, physical therapist Lynn Williams, Dan Melfi and Dave Altman discuss ... adjusted as changes occur in MS symptoms. A physical therapist experienced with MS can be helpful in designing, ...

  9. Plasma glutamine responses to high-intensity exercise before and after endurance training.

    PubMed

    Kargotich, Stephen; Goodman, Carmél; Dawson, Brian; Morton, Alan R; Keast, David; Joske, David J L

    2005-01-01

    Glutamine responses to strenuous interval exercise were examined before and after 6 weeks of endurance training. Glutamine measures were obtained before and after the interval exercise sessions and training in untrained males assigned to training (T; n = 10) or control (C; n = 10) groups. Before training, C and T group glutamine progressively decreased (p < 0.05) by 18% and 16%, respectively, by 150-min postinterval exercise. Over the training period C group glutamine did not change, while T group values increased (p < 0.05) by 14%. After training, glutamine again decreased (p < 0.05) by similar percentages (C = 16% and T = 15%) by 150-min postinterval exercise, but the T group recorded higher (p < 0.05) resting and postexercise glutamine concentrations than the C group. Training induced increases in glutamine may prevent the decline in glutamine levels following strenuous exercise falling below a threshold where immune function might be acutely compromised. PMID:16440504

  10. Physiological Responses to High-Intensity Interval Exercise Differing in Interval Duration.

    PubMed

    Tucker, Wesley J; Sawyer, Brandon J; Jarrett, Catherine L; Bhammar, Dharini M; Gaesser, Glenn A

    2015-12-01

    We determined the oxygen uptake (V[Combining Dot Above]O2), heart rate (HR), and blood lactate responses to 2 high-intensity interval exercise protocols differing in interval length. On separate days, 14 recreationally active males performed a 4 × 4 (four 4-minute intervals at 90-95% HRpeak, separated by 3-minute recovery at 50 W) and 16 × 1 (sixteen 1-minute intervals at 90-95% HRpeak, separated by 1-minute recovery at 50 W) protocol on a cycle ergometer. The 4 × 4 elicited a higher mean V[Combining Dot Above]O2 (2.44 ± 0.4 vs. 2.36 ± 0.4 L·min) and "peak" V[Combining Dot Above]O2 (90-99% vs. 76-85% V[Combining Dot Above]O2peak) and HR (95-98% HRpeak vs. 81-95% HRpeak) during the high-intensity intervals. Average power maintained was higher for the 16 × 1 (241 ± 45 vs. 204 ± 37 W), and recovery interval V[Combining Dot Above]O2 and HR were higher during the 16 × 1. No differences were observed for blood lactate concentrations at the midpoint (12.1 ± 2.2 vs. 10.8 ± 3.1 mmol·L) and end (10.6 ± 1.5 vs. 10.6 ± 2.4 mmol·L) of the protocols or ratings of perceived exertion (7.0 ± 1.6 vs. 7.0 ± 1.4) and Physical Activity Enjoyment Scale scores (91 ± 15 vs. 93 ± 12). Despite a 4-fold difference in interval duration that produced greater between-interval transitions in V[Combining Dot Above]O2 and HR and slightly higher mean V[Combining Dot Above]O2 during the 4 × 4, mean HR during each protocol was the same, and both protocols were rated similarly for perceived exertion and enjoyment. The major difference was that power output had to be reduced during the 4 × 4 protocol to maintain the desired HR.

  11. Carbohydrate supplementation and prolonged intermittent high-intensity exercise in adolescents: research findings, ethical issues and suggestions for the future.

    PubMed

    Phillips, Shaun M

    2012-10-01

    knowledge while safeguarding the health and well-being of young participants. It could be deemed unethical to continue study into carbohydrate supplementation while ignoring the potential health concerns and the possibility of generating similar performance enhancements using natural dietary interventions. Therefore, future work should investigate the influence o