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Sample records for heart rate performance

  1. Fighter pilots' heart rate, heart rate variation and performance during an instrument flight rules proficiency test.

    PubMed

    Mansikka, Heikki; Virtanen, Kai; Harris, Don; Simola, Petteri

    2016-09-01

    Increased task demand will increase the pilot mental workload (PMWL). When PMWL is increased, mental overload may occur resulting in degraded performance. During pilots' instrument flight rules (IFR) proficiency test, PMWL is typically not measured. Therefore, little is known about workload during the proficiency test and pilots' potential to cope with higher task demands than those experienced during the test. In this study, fighter pilots' performance and PMWL was measured during a real IFR proficiency test in an F/A-18 simulator. PMWL was measured using heart rate (HR) and heart rate variation (HRV). Performance was rated using Finnish Air Force's official rating scales. Results indicated that HR and HRV differentiate varying task demands in situations where variations in performance are insignificant. It was concluded that during a proficiency test, PMWL should be measured together with the task performance measurement. PMID:27109324

  2. Correlation between heart rate and performance during Olympic windsurfing competition.

    PubMed

    Chamari, Karim; Moussa-Chamari, Imen; Galy, Olivier; Chaouachi, Mustapha; Koubaa, Donia; Hassen, Chokri Ben; Hue, Olivier

    2003-05-01

    The aim of this study was to examine the heart rate (HR) response to Olympic windsurfing competition and to check if there was any correlation between racing HR, performance, and the variables measured during laboratory maximal exercise. Ten elite windsurfers [age: 20.93 (3.46) years; height: 178.10 (6.34) cm; body mass: 66.79 (5.90) kg] performed a laboratory maximal oxygen consumption (.VO(2max)) trial and national windsurf competitions wearing a HR monitor. One hundred and forty-three individual races were examined. Racing HR was expressed as a percentage of (1) HR(max) (maximal treadmill HR) and (2) HR(reserve) (HR(max)-HR(rest)). The performance (racing classification: RC, which is inversely proportional to performance) was significantly correlated to the racing HR response in both light wind (LW): LW-RC=-0.12(%HR(reserve))+13.03; r=-0.71, r(2)=0.50, p<0.001, and medium wind (MW): MW-RC=-0.11(%HR(reserve))+10.99; r=-0.66, r(2)=0.43, p<0.001. The results showed similar correlations between performance and %HR(max). Post racing lactate concentration was higher in LW compared to MW [7.14 (0.21) and 5.18 (2.02) mmol.l(-1), respectively]. There was a negative correlation between the highest racing HR (%HR(reserve)) of each athlete and the second ventilatory threshold expressed as a percentage of .VO(2max) ( r=-0.71, p<0.05). To summarize, this study showed that light and medium wind Olympic windsurfing performances are highly dependent on the capacity of the athlete to maintain a high HR for long periods of time. Furthermore, windsurfing is highly dependent on the athlete's physical fitness level as shown by the correlations between racing HRs and laboratory physiological variables. PMID:12682836

  3. Deceleration and acceleration capacities of heart rate associated with heart failure with high discriminating performance

    PubMed Central

    Hu, Wei; Jin, Xian; Zhang, Peng; Yu, Qiang; Yin, Guizhi; Lu, Yi; Xiao, Hongbing; Chen, Yueguang; Zhang, Dadong

    2016-01-01

    Accurate measurements of autonomic nerve regulation in heart failure (HF) were unresolved. The discriminating performance of deceleration and acceleration capacities of heart rate in HF was evaluated in 130 HF patients and 212 controls. Acceleration capacity and deceleration capacity were independent risk factors for HF in males, evaluated by multiple logistic regression analysis, with odds ratios (ORs) of 5.94 and 0.13, respectively. Acceleration capacity was also an independent risk factor for HF in females, with an OR of 8.58. Deceleration capacity was the best cardiac electrophysiological index to classify HF in males, with an area under the receiver operating characteristic curve (AUC) of 0.88. Deceleration capacity was the best classification factor of HF in females with an AUC of 0.97, significantly higher than even left ventricular ejection fraction (LVEF). Acceleration capacity also showed high performance in classifying HF in males (0.84) and females (0.92). The cut-off values of deceleration capacity for HF classification in males and females were 4.55 ms and 4.85 ms, respectively. The cut-off values of acceleration capacity for HF classification in males and females were −6.15 ms and −5.75 ms, respectively. Our study illustrates the role of acceleration and deceleration capacity measurements in the neuro-pathophysiology of HF. PMID:27005970

  4. Comparison of body composition, heart rate variability, aerobic and anaerobic performance between competitive cyclists and triathletes

    PubMed Central

    Arslan, Erşan; Aras, Dicle

    2016-01-01

    [Purpose] The aim of this study was to compare the body composition, heart rate variability, and aerobic and anaerobic performance between competitive cyclists and triathletes. [Subjects] Six cyclists and eight triathletes with experience in competitions voluntarily participated in this study. [Methods] The subjects’ body composition was measured with an anthropometric tape and skinfold caliper. Maximal oxygen consumption and maximum heart rate were determined using the incremental treadmill test. Heart rate variability was measured by 7 min electrocardiographic recording. The Wingate test was conducted to determine anaerobic physical performance. [Results] There were significant differences in minimum power and relative minimum power between the triathletes and cyclists. Anthropometric characteristics and heart rate variability responses were similar among the triathletes and cyclists. However, triathletes had higher maximal oxygen consumption and lower resting heart rates. This study demonstrated that athletes in both sports have similar body composition and aerobic performance characteristics. PMID:27190476

  5. Cortisol release, heart rate and heart rate variability in the horse and its rider: different responses to training and performance.

    PubMed

    von Lewinski, Mareike; Biau, Sophie; Erber, Regina; Ille, Natascha; Aurich, Jörg; Faure, Jean-Michel; Möstl, Erich; Aurich, Christine

    2013-08-01

    Although some information exists on the stress response of horses in equestrian sports, the horse-rider team is much less well understood. In this study, salivary cortisol concentrations, heart rate (HR) and heart rate variability (HRV), SDRR (standard deviation of beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat intervals) were analysed in horses and their riders (n=6 each) at a public performance and an identical rehearsal that was not open to the public. Cortisol concentrations increased in both horses and riders (P<0.001) but did not differ between performance and rehearsal. HR in horses and riders increased during the rehearsal and the public performance (P<0.001) but the increase in HR was more pronounced (P<0.01) in riders than in their horses during the public performance (from 91 ± 10 to 150 ± 15 beats/min) compared to the rehearsal (from 94 ± 10 to 118 ± 12 beats/min). The SDRR decreased significantly during the equestrian tasks in riders (P<0.001), but not in their horses. The RMSSD decreased in horses and riders (P<0.001) during rehearsal and performance, indicating a decrease in parasympathetic tone. The decrease in RMSSD in the riders was more pronounced (P<0.05) during the performance (from 32.6 ± 6.6 to 3.8 ± 0.3 ms) than during the rehearsal (from 27.5 ± 4.2 to 6.6 ± 0.6 ms). The study has shown that the presence of spectators caused more pronounced changes in cardiac activity in the riders than it did in their horses. PMID:23380228

  6. Attentional Focus and Performance Anxiety: Effects on Simulated Race-Driving Performance and Heart Rate Variability

    PubMed Central

    Mullen, Richard; Faull, Andrea; Jones, Eleri S.; Kingston, Kieran

    2012-01-01

    Previous studies have demonstrated that an external focus can enhance motor learning compared to an internal focus. The benefits of adopting an external focus are attributed to the use of less effortful automatic control processes, while an internal focus relies upon more effort-intensive consciously controlled processes. The aim of this study was to compare the effectiveness of a distal external focus with an internal focus in the acquisition of a simulated driving task and subsequent performance in a competitive condition designed to increase state anxiety. To provide further evidence for the automatic nature of externally controlled movements, the study included heart rate variability (HRV) as an index of mental effort. Sixteen participants completed eight blocks of four laps in either a distal external or internal focus condition, followed by two blocks of four laps in the competitive condition. During acquisition, the performance of both groups improved; however, the distal external focus group outperformed the internal focus group. The poorer performance of the internal focus group was accompanied by a larger reduction in HRV, indicating a greater investment of mental effort. In the competition condition, state anxiety increased, and for both groups, performance improved as a function of the increased anxiety. Increased heart rate and self-reported mental effort accompanied the performance improvement. The distal external focus group also outperformed the internal focus group across both neutral and competitive conditions and this more effective performance was again associated with lower levels of HRV. Overall, the results offer support for the suggestion that an external focus promotes a more automatic mode of functioning. In the competitive condition, both foci enhanced performance and while the improved performance may have been achieved at the expense of greater compensatory mental effort, this was not reflected in HRV scores. PMID:23133431

  7. Cognitive Performance and Heart Rate Variability: The Influence of Fitness Level

    PubMed Central

    Luque-Casado, Antonio; Zabala, Mikel; Morales, Esther; Mateo-March, Manuel; Sanabria, Daniel

    2013-01-01

    In the present study, we investigated the relation between cognitive performance and heart rate variability as a function of fitness level. We measured the effect of three cognitive tasks (the psychomotor vigilance task, a temporal orienting task, and a duration discrimination task) on the heart rate variability of two groups of participants: a high-fit group and a low-fit group. Two major novel findings emerged from this study. First, the lowest values of heart rate variability were found during performance of the duration discrimination task, compared to the other two tasks. Second, the results showed a decrement in heart rate variability as a function of the time on task, although only in the low-fit group. Moreover, the high-fit group showed overall faster reaction times than the low-fit group in the psychomotor vigilance task, while there were not significant differences in performance between the two groups of participants in the other two cognitive tasks. In sum, our results highlighted the influence of cognitive processing on heart rate variability. Importantly, both behavioral and physiological results suggested that the main benefit obtained as a result of fitness level appeared to be associated with processes involving sustained attention. PMID:23437276

  8. Acute Effect of Decaffeinated Coffee on Heart Rate, Blood Pressure, and Exercise Performance in Healthy Subjects

    PubMed Central

    Prakash, Ravi; Kaushik, Vidya S.

    1988-01-01

    The effect of decaffeinated coffee on the cardiovascular exercise performance in nine healthy volunteers was evaluated in a double-blind randomized fashion. The heart rate, blood pressure, and duration of exercise were unchanged, and no arrhythmias or ischemic changes were seen on the electrocardiogram after drinking decaffeinated coffee. It was concluded that decaffeinated coffee has no discernible, acute, adverse cardiovascular effects. PMID:3339645

  9. Target Heart Rate Calculator

    MedlinePlus

    ... My Saved Articles » My ACS » + - Text Size Target Heart Rate Calculator Compute your best workout Enter your age ... is your age? years. How to Check Your Heart Rate Right after you stop exercising, take your pulse: ...

  10. Success rates and prognosis of heart valvuloplasty and valve replacement performed for elderly patients

    PubMed Central

    Liu, Weichao; He, Fei; Shi, Gongning

    2015-01-01

    Objective: To analyze the success rates and prognosis of heart valvuloplasty and valve replacement for elderly patients, and to provide clinical evidence. Methods: A total of 1240 patients who received heart valve surgeries in our hospital from June 2004 to October 2014 were selected and retrospectively analyzed. They were divided into two groups based on age (60), and those older than 60 (Group B) suffered from rheumatic valvular heart disease and nonrheumatic valvular heart disease including degenerative valve disease. Mitral valve replacement (MVR), tricuspid valve replacement (TVR), aortic valve replacement (AVR), double valve replacement (DVR), mitral valvuloplasty (MVP) and tricuspid valvuloplasty (TVP) were performed by using bioprosthetic and mechanical valves. Before surgery, coronary angiography, coronary artery bypass grafting (CABG), left atrial thrombectomy, left atrial wall folding and radiofrequency ablation were conducted. For the patients younger than 60 (Group A) who had congenital heart disease, rheumatic valvular heart disease and valvular heart disease, MVR, AVR, DVR, MVP, TVP and closed cuspid commissurotomy were performed with bioprosthetic and mechanical valves. The two groups were then monitored. Results: The mortality rates of Group A and Group B were 2.7% (16 cases) and 3.1% (20 cases) respectively. They died mainly of malignant ventricular arrhythmias, multiple organ failure, left ventricular rupture, low cardiac output syndrome, acute renal failure, respiratory failure, upper gastrointestinal bleeding, mechanical valve failure and cerebrovascular accident. The two groups had significantly different application rates of bioprosthetic valve, times of auxiliary ventilation and hospitalization stay lengths (P<0.05), but left ventricular ejection fractions, left ventricular end-diastolic diameters (LVEDDs), mortality rates as well as times of aortic cross-clamping and cardiopulmonary bypass were similar (P>0.05). LVEDD, complicated coronary

  11. Heart rate, anxiety and performance of residents during a simulated critical clinical encounter: a pilot study

    PubMed Central

    2014-01-01

    Background High-fidelity patient simulation has been praised for its ability to recreate lifelike training conditions. The degree to which high fidelity simulation elicits acute emotional and physiologic stress among participants – and the influence of acute stress on clinical performance in the simulation setting – remain areas of active exploration. We examined the relationship between residents’ self-reported anxiety and a proxy of physiologic stress (heart rate) as well as their clinical performance in a simulation exam using a validated assessment of non-technical skills, the Ottawa Crisis Resource Management Global Rating Scale (Ottawa GRS). Methods This was a prospective observational cohort study of emergency medicine residents at a single academic center. Participants managed a simulated clinical encounter. Anxiety was assessed using a pre- and post-simulation survey, and continuous cardiac monitoring was performed on each participant during the scenario. Performance in the simulation scenario was graded by faculty raters using a critical actions checklist and the Ottawa GRS instrument. Results Data collection occurred during the 2011 academic year. Of 40 eligible residents, 34 were included in the analysis. The median baseline heart rate for participants was 70 beats per minute (IQR: 62 – 78). During the simulation, the median maximum heart rate was 140 beats per minute (IQR: 137 – 151). The median minimum heart rate during simulation was 81 beats per minute (IQR: 72 – 92), and mean heart rate was 117 beats per minute (95% CI: 111 – 123). Pre- and post-simulation anxiety scores were equal (mean 3.3, IQR: 3 to 4). The minimum and maximum Overall Ottawa GRS scores were 2.33 and 6.67, respectively. The median Overall score was 5.63 (IQR: 5.0 to 6.0). Of the candidate predictors of Overall performance in a multivariate logistic regression model, only PGY status showed statistical significance (P = 0.02). Conclusions Simulation is associated

  12. Autonomic response to tactical pistol performance measured by heart rate variability.

    PubMed

    Thompson, Andrew G; Swain, David P; Branch, J David; Spina, Robert J; Grieco, Carmine R

    2015-04-01

    This study evaluated changes in autonomic tone during a tactical pistol competition. At rest and during a match, heart rate variability (HRV) was examined in 28 healthy subjects. Heart rate variability time-domain variables (including interbeat interval [IBI]) and frequency-domain variables (low frequency [LF], high frequency [HF], total power [TP]) measured during shooting were subtracted from those measured during rest to produce Δs. The shooting task involved several, rapid tactical maneuvers. Raw time to completion and inaccurate shots (points down [PDs]) were recorded and combined to form a match score where lower values indicated superior shooting performance. Mean (±SD) raw time was 135.9 ± 34.1 seconds, PDs were 78 ± 34, and match score was 175.3 ± 39.8. Shooting decreased IBI (i.e., increased heart rate) and LF. ΔLF, ΔHF, and ΔTP were independent of ΔIBI. Raw time was significantly (p ≤ 0.05) correlated to shooting IBI (r = 0.404) and ΔIBI (r = -0.426). Points down were significantly correlated to ΔTP (r = 0.416) and ΔLF (r = 0.376). Match score was significantly correlated to ΔIBI (r = -0.458), ΔHF (r = 0.467), ΔLF (r = 0.377), and ΔTP (r = 0.451). In conclusion, individuals with a greater decrease in IBI (and thus heart rate) performed better by accomplishing the match faster. Individuals with less change in stress-related HRV measures (LF, HF, and TP) performed better through improved accuracy. Thus, HRV-derived sympathetic response is significantly related to shooting performance and should be used to assess marksmanship effectiveness under duress. PMID:25029000

  13. Failure to uncover the effects of unconscious symbiotic fantasies on heart rate and fine motor performance.

    PubMed

    Malik, R; Apel, S; Nelham, C; Rutkowski, C; Ladd, H

    1997-12-01

    18 men and 18 women were tachistoscopically shown the stimuli MOMMY AND I ARE ONE, DADDY AND I ARE ONE, and MYMMO NAD I REA ENO, at subjective thresholds (subliminal condition) and at 500 msec. (supraliminal condition). Following exposure to each stimulus, subjects performed a fine motor line-tracing task. Heart rate was monitored continuously during stimulus presentation and the fine motor task. Analysis showed subjects did not respond more positively with decreased heart rate or fewer errors on the fine motor task following the MOMMY message than the anagram phrase, thereby providing no support for the hypotheses. No correlation was found between responsiveness to the MOMMY message and scores on measures of self-perception and kinship. In the light of mounting negative evidence, the validity of the method of subliminal psychodynamic activation is questioned. PMID:9450275

  14. Heart Rate Monitors

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Under a NASA grant, Dr. Robert M. Davis and Dr. William M. Portnoy came up with a new type of electrocardiographic electrode that would enable long term use on astronauts. Their invention was an insulated capacitive electrode constructed of a thin dielectric film. NASA subsequently licensed the electrode technology to Richard Charnitski, inventor of the VersaClimber, who founded Heart Rate, Inc., to further develop and manufacture personal heart monitors and to produce exercise machines using the technology for the physical fitness, medical and home markets. Same technology is on both the Home and Institutional Model VersaClimbers. On the Home Model an infrared heart beat transmitter is worn under exercise clothing. Transmitted heart rate is used to control the work intensity on the VersaClimber using the heart rate as the speedometer of the exercise. This offers advantages to a full range of users from the cardiac rehab patient to the high level physical conditioning of elite athletes. The company manufactures and markets five models of the 1*2*3 HEART RATE monitors that are used wherever people exercise to accurately monitor their heart rate. Company is developing a talking heart rate monitor that works with portable headset radios. A version of the heart beat transmitter will be available to the manufacturers of other aerobic exercise machines.

  15. The effect of heart rate variability biofeedback on performance psychology of basketball players.

    PubMed

    Paul, Maman; Garg, Kanupriya

    2012-06-01

    Coping with pressure and anxiety is an ineluctable demand of sports performance. Heart rate variability (HRV) Biofeedback (BFB) shall be used as a tool for self regulating physiological responses resulting in improved psycho physiological interactions. For further analysis, the present study has been designed to examine the relationship between anxiety and performance and also effectiveness of biofeedback protocol to create stress-eliciting situation in basketball players. Thirty basketball players of university level and above (both male and female) aged 18-28 years, who scored a minimum of 20 in state trait anxiety inventory, were randomly divided into three equal groups- Experimental (Biofeedback) group, Placebo group and Control (No Treatment) group. The BFB group received HRV BFB training for 10 consecutive days for 20 min that included breathing at individual's resonant frequency through a pacing stimulus; Placebo group was shown motivational video clips for 10 consecutive days for 10 min, whereas No Treatment Control group was not given any intervention. Two way repeated measure ANOVA was applied to analyze the differences within and between the groups. Anxiety, coping self-efficacy, heart rate variability, respiration rate, and performance (dribbling, passing and shooting) at session 1, 10 and 1 month follow up were statistically significant in each group along with interaction of group and time (p < 0.001). Also, all the measures showed statistically significant inter group difference (p < 0.05). The findings are harmonious with existing data on HRV BFB as a strategy for dealing with anxiety. The Placebo group showed improvement in self efficacy and performance post training. The Control group showed no change in any variable except performance. The results of the study support the idea that HRV BFB lowers the anxiety and thus there seems to be a potential association between HRV BFB and performance optimization. PMID:22402913

  16. Heart rate turbulence.

    PubMed

    Cygankiewicz, Iwona

    2013-01-01

    Heart rate turbulence (HRT) is a baroreflex-mediated biphasic reaction of heart rate in response to premature ventricular beats. Heart rate turbulence is quantified by: turbulence onset (TO) reflecting the initial acceleration of heart rate following premature beat and turbulence slope (TS) describing subsequent deceleration of heart rate. Abnormal HRT identifies patients with autonomic dysfunction or impaired baroreflex sensitivity due to variety of disorders, but also may reflect changes in autonomic nervous system induced by different therapeutic modalities such as drugs, revascularization, or cardiac resynchronization therapy. More importantly, impaired HRT has been shown to identify patients at high risk of all-cause mortality and sudden death, particularly in postinfarction and congestive heart failure patients. It should be emphasized that abnormal HRT has a well-established role in stratification of postinfarction and heart failure patients with relatively preserved left ventricular ejection fraction. The ongoing clinical trials will document whether HRT can be used to guide implantation of cardioverter-defibrillators in this subset of patients, not covered yet by ICD guidelines. This review focuses on the current state-of-the-art knowledge regarding clinical significance of HRT in detection of autonomic dysfunction and regarding the prognostic significance of this parameter in predicting all-cause mortality and sudden death. PMID:24215748

  17. Heart Rate Monitor

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the mid 70's, NASA saw a need for a long term electrocardiographic electrode suitable for use on astronauts. Heart Rate Inc.'s insulated capacitive electrode is constructed of thin dielectric film applied to stainless steel surface, originally developed under a grant by Texas Technical University. HRI, Inc. was awarded NASA license and continued development of heart rate monitor for use on exercise machines for physical fitness and medical markets.

  18. Heart failure performance measures: do they have an impact on 30-day readmission rates?

    PubMed

    Mazimba, Sula; Grant, Nakash; Parikh, Analkumar; Mwandia, George; Makola, Diklar; Chilomo, Christine; Redko, Cristina; Hahn, Harvey S

    2013-01-01

    Congestive heart failure (CHF) accounts for more health care costs than any other diagnosis. Readmissions contribute to this expenditure. The authors evaluated the relationship between adherence to performance metrics and 30-day readmissions. This was a retrospective study of 6063 patients with CHF between 2001 and 2008. Data were collected for 30-day readmissions and compliance with CHF performance measures at discharge. Rates of readmission for CHF increased from 16.8% in 2002 to 24.8% in 2008. Adherence to performance measures increased concurrently from 95.8% to 99.9%. Except for left ventricular function (LVF) assessment, the 30-day readmission rate was not associated with adherence to performance measures. Readmitted patients had twice the odds of not having their LVF assessed (odds ratio = 2.0; P < .00005; 95% confidence interval = 1.45-2.63). CHF performance measures, except for the LVF assessment, have little relationship to 30-day readmissions. Further studies are needed to identify performance measures that correlate with quality of care. PMID:23110998

  19. The performance and reliability of wavelet denoising for Doppler ultrasound fetal heart rate signal preprocessing.

    PubMed

    Papadimitriou, S; Papadopoulos, V; Gatzounas, D; Tzigounis, V; Bezerianos, A

    1997-01-01

    The present paper deals with the performance and the reliability of a Wavelet Denoising method for Doppler ultrasound Fetal Heart Rate (FHR) recordings. It displays strong evidence that the denoising process extracts the actual noise components. The analysis is approached with three methods. First, the power spectrum of the denoised FHR displays more clearly an 1/fa scaling law, i.e. the characteristic of fractal time series. Second, the rescaled scale analysis technique reveals a Hurst exponent at the range of 0.7-0.8 that corresponds to a long memory persistent process. Moreover, the variance of the Hurst exponent across time scales is smaller at the denoised signal. Third, a chaotic attractor reconstructed with the embedding dimension technique becomes evident at the denoised signals, while it is completely obscured at the unfiltered ones. PMID:10179728

  20. The Role of Shape and Heart Rate on the Performance of the Left Ventricle.

    PubMed

    Song, Zeying; Borazjani, Iman

    2015-11-01

    The left ventricle function is to pump the oxygenated blood through the circulatory system. Ejection fraction is the main noninvasive parameter for detecting heart disease (healthy >55%), and it is thought to be the main parameter affecting efficiency. However, the effects of other parameters on efficiency have yet to be investigated. We investigate the effect of heart rate and left ventricle shape by carrying out 3D numerical simulations of a left ventricle at different heart rates and perturbed geometries under constant, normal ejection fraction. The simulation using the immersed boundary method provide the 3D flow and pressure fields, which enable direct calculation of a new hemodynamic efficiency (H-efficiency) parameter, which does not depend on any reference pressure. The H-efficiency is defined as the ratio of flux of kinetic energy (useful power) to the total cardiac power into the left ventricle control volume. Our simulations show that H-efficiency is not that sensitive to heart rate but is maximized at around normal heart rate (72 bpm). Nevertheless, it is more sensitive to the shape of the left ventricle, which affects the H-efficiency by as much as 15% under constant ejection fraction. PMID:26312776

  1. Modelling Heart Rate Kinetics

    PubMed Central

    Zakynthinaki, Maria S.

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual’s cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women). PMID:25876164

  2. Modelling heart rate kinetics.

    PubMed

    Zakynthinaki, Maria S

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual's cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women). PMID:25876164

  3. Monitoring changes in physical performance with heart rate measures in young soccer players.

    PubMed

    Buchheit, M; Simpson, M B; Al Haddad, H; Bourdon, P C; Mendez-Villanueva, A

    2012-02-01

    The aim of the present study was to verify the validity of using exercise heart rate (HRex), HR recovery (HRR) and post-exercise HR variability (HRV) during and after a submaximal running test to predict changes in physical performance over an entire competitive season in highly trained young soccer players. Sixty-five complete data sets were analyzed comparing two consecutive testing sessions (3-4 months apart) collected on 46 players (age 15.1 ± 1.5 years). Physical performance tests included a 5-min run at 9 km h(-1) followed by a seated 5-min recovery period to measure HRex, HRR and HRV, a counter movement jump, acceleration and maximal sprinting speed obtained during a 40-m sprint with 10-m splits, repeated-sprint performance and an incremental running test to estimate maximal cardiorespiratory function (end test velocity V (Vam-Eval)). Possible changes in physical performance were examined for the players presenting a substantial change in HR measures over two consecutive testing sessions (greater than 3, 13 and 10% for HRex, HRR and HRV, respectively). A decrease in HRex or increase in HRV was associated with likely improvements in V (Vam-Eval); opposite changes led to unclear changes in V (Vam-Eval). Moderate relationships were also found between individual changes in HRR and sprint [r = 0.39, 90% CL (0.07;0.64)] and repeated-sprint performance [r = -0.38 (-0.05;-0.64)]. To conclude, while monitoring HRex and HRV was effective in tracking improvements in V (Vam-Eval), changes in HRR were moderately associated with changes in (repeated-)sprint performance. The present data also question the use of HRex and HRV as systematic markers of physical performance decrements in youth soccer players. PMID:21656232

  4. The Effects of Guided Imagery on Heart Rate Variability in Simulated Spaceflight Emergency Tasks Performers

    PubMed Central

    Yijing, Zhang; Xiaoping, Du; Fang, Liu; Xiaolu, Jing; Bin, Wu

    2015-01-01

    Objectives. The present study aimed to investigate the effects of guided imagery training on heart rate variability in individuals while performing spaceflight emergency tasks. Materials and Methods. Twenty-one student subjects were recruited for the experiment and randomly divided into two groups: imagery group (n = 11) and control group (n = 10). The imagery group received instructor-guided imagery (session 1) and self-guided imagery training (session 2) consecutively, while the control group only received conventional training. Electrocardiograms of the subjects were recorded during their performance of nine spaceflight emergency tasks after imagery training. Results. In both of the sessions, the root mean square of successive differences (RMSSD), the standard deviation of all normal NN (SDNN), the proportion of NN50 divided by the total number of NNs (PNN50), the very low frequency (VLF), the low frequency (LF), the high frequency (HF), and the total power (TP) in the imagery group were significantly higher than those in the control group. Moreover, LF/HF of the subjects after instructor-guided imagery training was lower than that after self-guided imagery training. Conclusions. Guided imagery was an effective regulator for HRV indices and could be a potential stress countermeasure in performing spaceflight tasks. PMID:26137491

  5. 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

  6. Seasonal changes in physical performance and heart rate variability in high level futsal players.

    PubMed

    Oliveira, R S; Leicht, A S; Bishop, D; Barbero-Álvarez, J C; Nakamura, F Y

    2013-05-01

    The aim of this study was to determine the changes in physical performance and resting heart rate variability (HRV) in professional futsal players during the pre-season and in-season training periods. 11 athletes took part in the study (age=24.3±2.9 years; height=176.3±5.2 cm; weight=76.1±6.3 kg), and performed a repeated-sprint ability (RSA) test [6×40 m (20+20 m with a 180° change of direction) sprints separated by 20 s of passive recovery] and Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) at 3 different moments (M1=beginning of pre-season; M2=end of pre-season; M3=mid in-season). The HRV indices were assessed at the same moments. After the short pre-season (3-week), mean RSA time (RSAmean) (M1=7.43±0.2 s; M2=7.24±0.2 s; P=0.003), decrement in RSA performance (RSAdecrement) (M1=6.7±0.3%; M2=5.0±0.9%; P=0.001), and Yo-Yo IR1 distance (M1=1.244±298 m; M2=1.491±396 m; P=0.002) were significantly improved (P<0.05). During the in-season (i. e., M3), performance in Yo-Yo IR1 and RSAmean were maintained. In contrast, RSAbest (M2=6.89±0.2 to M3=6.69±0.3; P=0.001) was improved and RSAdecrement (M2=5.0±0.9% to M3=6.6±0.9%; P=0.001) was impaired. At M2, there was an increase in HRV vagal-related indices compared with M1 that was maintained at M3. In conclusion, after a short pre-season, futsal players improved their RSA and Yo-Yo IR1 performance with concomitant improvements in HRV. These indices were maintained during the in-season period while RSAbest was improved and RSAdecrement impaired. Frequent monitoring of these performances and HRV indices may assist with identification of individual training adaptations and/or early signs of maladaption. PMID:23143705

  7. All about Heart Rate (Pulse)

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More All About Heart Rate (Pulse) Updated:Apr 19,2016 ... Sodium and Salt 3 Low Blood Pressure 4 All About Heart Rate (Pulse) 5 How to Eat ...

  8. A higher illuminance induces alertness even during office hours: findings on subjective measures, task performance and heart rate measures.

    PubMed

    Smolders, K C H J; de Kort, Y A W; Cluitmans, P J M

    2012-08-20

    Nocturnal white light exposure has shown marked results on subjective and objective indicators of alertness, vitality and mood, yet effects of white light during daytime and under usual office work conditions have not been investigated extensively. The current study employed a mixed-group design (N=32), testing effects of two illuminance levels (200lx or 1000lx at eye level, 4000K) during one hour of morning versus afternoon exposure. In four repeated blocks, subjective reports, objective performance and physiological arousal were measured. Results showed effects of illuminance on subjective alertness and vitality, sustained attention in tasks, and heart rate and heart rate variability. Participants felt less sleepy and more energetic in the high versus the low lighting condition, had shorter reaction times on the psychomotor vigilance task and increased physiological arousal. Effects of illuminance on the subjective measures, as well as those on heart rate were not dependent on time of day or duration of exposure. Performance effects were most pronounced in the morning sessions and towards the end of the one-hour exposure period. The effect on heart rate variability was also most pronounced at the end of the one-hour exposure. The results demonstrate that even under normal, i.e., neither sleep nor light deprived conditions, more intense light can improve feelings of alertness and vitality, as well as objective performance and physiological arousal. PMID:22564492

  9. Physiological and performance adaptations to an in-season soccer camp in the heat: associations with heart rate and heart rate variability.

    PubMed

    Buchheit, M; Voss, S C; Nybo, L; Mohr, M; Racinais, S

    2011-12-01

    The aim of the present study was to examine the associations between adaptive responses to an in-season soccer training camp in the heat and changes in submaximal exercising heart rate (HRex, 5-min run at 9  km/h), postexercise HR recovery (HRR) and HR variability (HRV). Fifteen well-trained but non-heat-acclimatized male adult players performed a training week in Qatar (34.6 ± 1.9°C wet bulb globe temperature). HRex, HRR, HRV (i.e. the standard deviation of instantaneous beat-to-beat R-R interval variability measured from Poincaré plots SD1, a vagal-related index), creatine kinase (CK) activity, plasma volume (PV) changes, and post-5-min run rate of perceived exertion (RPE) were collected at six occasions in temperate environmental conditions (22°C). Players also performed the yo-yo intermittent recovery test level 1 (Yo-Yo IR1) in the same environmental conditions (22°C), both at the beginning and at the end of the training week. Throughout the intervention, HRex and HRV showed decreasing (P < 0.001) and increasing (P < 0.001) trends, respectively, while HRR remained unaffected (P = 0.84). Changes in HRex [-0.52, 90% confidence limits (-0.64; -0.38), P < 0.001] and SD1 [0.35 (0.19; 0.49), P < 0.001] were correlated with those in PV. There was no change in RPE (P = 0.92), while CK varied according to training contents (P < 0.001), without association with HR-derived measures. Yo-Yo IR1 performance increased by 7 ± 9% (P = 0.009), which was correlated with changes in HRex [-0.64 (-0.84; -0.28), P = 0.01]. In conclusion, we found that an in-season soccer training camp in the heat can significantly improve PV and soccer-specific physical performance; both of which are associated with changes in HRex during a 5-min submaximal run. PMID:22092960

  10. Effects of the presentation of false heart-rate feedback on the performance of two common heartbeat-detection tasks.

    PubMed

    Phillips, G C; Jones, G E; Rieger, E J; Snell, J B

    1999-07-01

    Research has indicated that performance on heartbeat counting tasks may be influenced by beliefs about heart rate. Sixty male subjects were administered the Schandry heartbeat counting task after viewing fast, slow, or no heart rate feedback. Subjects were also administered the Whitehead signal-detection type task. Results indicated that subjects who received fast or no heartbeat feedback performed better on the Schandry task than subjects who received slow feedback. Feedback presentation did not affect performance on the Whitehead task. These results suggest that the Schandry task is influenced by external variables (expectations, beliefs) beyond pure awareness of "discrete" visceral sensations and, thus, may not be as powerful a method for determining awareness of individual heartbeats as some other paradigms. PMID:10432800

  11. Supplemental Protein during Heavy Cycling Training and Recovery Impacts Skeletal Muscle and Heart Rate Responses but Not Performance.

    PubMed

    D'Lugos, Andrew C; Luden, Nicholas D; Faller, Justin M; Akers, Jeremy D; McKenzie, Alec I; Saunders, Michael J

    2016-01-01

    The effects of protein supplementation on cycling performance, skeletal muscle function, and heart rate responses to exercise were examined following intensified (ICT) and reduced-volume training (RVT). Seven cyclists performed consecutive periods of normal training (NT), ICT (10 days; average training duration 220% of NT), and RVT (10 days; training duration 66% of NT). In a crossover design, subjects consumed supplemental carbohydrate (CHO) or an equal amount of carbohydrate with added protein (CP) during and following each exercise session (CP = +0.94 g/kg/day protein during ICT; +0.39 g/kg/day during RVT). A 30-kilometer time trial performance (following 120 min at 50% Wmax) was modestly impaired following ICT (+2.4 ± 6.4% versus NT) and returned to baseline levels following RVT (-0.7 ± 4.5% versus NT), with similar responses between CHO and CP. Skeletal muscle torque at 120 deg/s benefited from CP, compared to CHO, following ICT. However, this effect was no longer present at RVT. Following ICT, muscle fiber cross-sectional area was increased with CP, while there were no clear changes with CHO. Reductions in constant-load heart rates (at 50% Wmax) following RVT were likely greater with CP than CHO (-9 ± 9 bpm). Overall it appears that CP supplementation impacted skeletal muscle and heart rate responses during a period of heavy training and recovery, but this did not result in meaningful changes in time trial performance. PMID:27618091

  12. Heart rate variability and heart rate recovery as prognostic factors

    PubMed Central

    GRAD, COSMIN

    2015-01-01

    Background and aim Heart rate (HR) can appear static and regular at rest, during exercise or recovery after exercise. However, HR is constantly adjusted due to factors such as breathing, blood pressure control, thermoregulation and the renin-angiotensin system, leading to a more dynamic response that can be quantified using HRV (heart rate variability). HRV is defined as the deviation in time between successive normal heart beat and is a noninvasive method to measure the total variation in a number of HR interval. HRV can serve as measure of autonomic activity of sino-atrial node. The aim of the study was to determine the influence of certain clinical and paraclinical parameters on heart rate recovery after exercise in patients with ischemic heart disease and the relation with HRV using 24 h Holter monitoring. Methods The study included 46 patients who were submitted to cardiovascular exercise stress test and also to 24 h Holter EKG monitoring. Subjects had a mean age of 56.2±11.2 years, with a minimum of 25 and a maximum of 79 years. The study included 22 (47.8%) men and 24 (52.2%) women. Statistical analysis was performed using MedCalc software version 14.8.1. Multivariate analysis consisted of the construction of several multiple linear regression models. A p value of 0.05 was considered statistically significant. Results The HRV values (time domain) were all lower in the IHD compared with the group without coronary heart disease, even if the difference is not statistically significant. Also rest and maximal HR values were similar but during the test varies in the sense that those with IHD had higher values of rest and maximal HR and lower HRR, but not statistically significant. Conclusions HRV is a very easy and safe method if there is an available device and it is used for evaluation of the autonomic nervous system in many cardiovascular diseases, but also in other pathologies. In uncomplicated ischemic heart disease HRV is depressed, but not significant. HRR

  13. Tachycardia | Fast Heart Rate

    MedlinePlus

    ... Prevention & Treatment of High Blood Pressure High Blood Pressure Tools & Resources ... signals in the heart's upper chambers fire abnormally, which interferes with electrical signals coming from ...

  14. Measures of skin conductance and heart rate in alcoholic men and women during memory performance

    PubMed Central

    Poey, Alan; Ruiz, Susan Mosher; Marinkovic, Ksenija; Oscar-Berman, Marlene

    2015-01-01

    We examined abnormalities in physiological responses to emotional stimuli associated with long-term chronic alcoholism. Skin conductance responses (SCR) and heart rate (HR) responses were measured in 32 abstinent alcoholic (ALC) and 30 healthy nonalcoholic (NC) men and women undergoing an emotional memory task in an MRI scanner. The task required participants to remember the identity of two emotionally-valenced faces presented at the onset of each trial during functional magnetic resonance imaging (fMRI) scanning. After viewing the faces, participants saw a distractor image (an alcoholic beverage, nonalcoholic beverage, or scrambled image) followed by a single probe face. The task was to decide whether the probe face matched one of the two encoded faces. Skin conductance measurements (before and after the encoded faces, distractor, and probe) were obtained from electrodes on the index and middle fingers on the left hand. HR measurements (beats per minute before and after the encoded faces, distractor, and probe) were obtained by a pulse oximeter placed on the little finger on the left hand. We expected that, relative to NC participants, the ALC participants would show reduced SCR and HR responses to the face stimuli, and that we would identify greater reactivity to the alcoholic beverage stimuli than to the distractor stimuli unrelated to alcohol. While the beverage type did not differentiate the groups, the ALC group did have reduced skin conductance and HR responses to elements of the task, as compared to the NC group. PMID:26020002

  15. Target Heart Rates

    MedlinePlus

    ... a Healthy Heart Healthy Kids Our Kids Programs Childhood Obesity What is childhood obesity? Overweight in Children BMI in Children Is Childhood Obesity an Issue in Your Home? Addressing your Child's ...

  16. Effects of Ramadan Fasting on Body Composition, Aerobic Performance and Lactate, Heart Rate and Perceptual Responses in Young Soccer Players

    PubMed Central

    Güvenç, Alpay

    2011-01-01

    The purpose of this study was to examine the effects of Ramadan fasting on body composition, aerobic exercise performance and blood lactate, heart rate and perceived exertion in regularly trained young soccer players. Sixteen male soccer players participated in this study. Mean age, stature, body mass and training age of the players were 17.4±1.2 years, 175.4±3.6 cm, 69.6±4.3 kg and 5.1±1.3 years, respectively. During the Ramadan period, all subjects voluntarily chose to follow the fasting guidelines and abstained from eating and drinking from sunrise to sunset. Body composition, hydration status, dietary intake and sleep duration were assessed on four occasions: before Ramadan, at the beginning of Ramadan, at the end of Ramadan and 2 weeks after the end of Ramadan. On each occasion, aerobic exercise performance and blood lactate, heart rate and rating of perceived exertion responses of players were also determined during an incremental running test. Repeated measures of ANOVA revealed that body mass, percentage of body fat, fat-free mass, hydration status, daily sleeping time and daily energy and macronutrient intake of players did not vary significantly throughout the study period (p>0.05). However, players experienced a small but significant decrease in skinfold thicknesses over the course of the study (p<0.05). Although ratings of perceived exertion at submaximal workloads increased during Ramadan (p<0.05), blood lactate and heart rate responses had decreased by the end of Ramadan (p<0.05). In line with these changes, peak running performance and running velocity at anaerobic threshold also improved by the end of Ramadan (p<0.05). Improvements in aerobic exercise performance with time were probably due to the effects of pre-season training program that was performed after the break of the fast (Iftar) during the month of Ramadan. The results of the present study suggest that if regular training regimen, body fluid balance, daily energy intake and sleep

  17. Blood Pressure vs. Heart Rate

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Blood Pressure vs. Heart Rate Updated:Aug 30,2016 Blood ... last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

  18. Fetal Heart Rate Response to Maternal Exercise.

    PubMed

    Monga, Manju

    2016-09-01

    Current guidelines regarding recommended exercise in pregnancy appear consistent with reported research regarding fetal heart changes in response to maternal exercise. Fetal heart rate increases during pregnancy, but maternal exercise appears well tolerated if performed in uncomplicated pregnancies and not in the supine position. Maximal levels of exercise that are well tolerated by the fetus have not yet been well defined; however, recent literature suggests that sustained exercise during pregnancy may have beneficial effects on autonomic control of fetal heart rate and variability that may lead to long-term health benefits. PMID:27388963

  19. Dimensional analysis of heart rate variability in heart transplant recipients

    SciTech Connect

    Zbilut, J.P.; Mayer-Kress, G.; Geist, K.

    1987-01-01

    We discuss periodicities in the heart rate in normal and transplanted hearts. We then consider the possibility of dimensional analysis of these periodicities in transplanted hearts and problems associated with the record.

  20. Assessment of gravitational stress on heart rate variability during maneuvers on high performance jet flights.

    PubMed

    Di Rienzo, Marco; Castiglioni, Paolo; Meriggi, Paolo; Rizzo, Francesco; Trivelloni, Pierandrea; Cacopardo, Salvatore; Guadagno, Anton Giulio

    2010-01-01

    The Push-Pull Effect (PPE) is a physiological phenomenon defined as a reduction of +Gz tolerance induced by a previous exposure to a -Gz acceleration, that may lead to loss of consciousness. Aim of this study was to evaluate, for the first time, the cardiac rhythm changes associated with PPE during real flights. Data were collected in 3 pilots during flights on the Aermacchi MB- 339-CD aircraft. In each flight, lasting about 60 minutes, ECG, respiration and 3D accelerations were recorded by a new smart garment (the MagIC System). The flight protocol included a maneuver eliciting a reference +5Gz acceleration for 15 seconds (Ref+5G), followed, after a while, by a push-pull maneuver with a profile characterized by a 5-s acceleration at -1Gz (PP-1G) and, with a 1G/s onset, by 15 seconds at +5Gz (PP+5G), so to induce the push-pull gravitational stress. From each ECG recording, a beat-by-beat RR Interval (RRI) series was derived. RRI mean, standard deviation (SDNN) and the RRI Root Mean Square of Successive Difference (RMSSD) were estimated in each pilot during the Ref+5G and the PP+5G maneuvers. As compared with Ref+5G, all pilots displayed significant reductions in RRI mean, SDNN and RMSSD during PP+5G. These findings are compatible with a PP-induced enhancement in the sympathetic drive to the heart -as shown by the reduction in RRI mean and SDNN- and a concomitant deactivation of the parasympathetic control as shown by the reduction in RMSSD. PMID:21097262

  1. The Effects of an Intervention Strategy on Children's Heart Rates and Skill Performance

    ERIC Educational Resources Information Center

    Ignico, Arlene; Corson, Arleen; Vidoni, Carla

    2006-01-01

    The purpose of this project was to examine the effectiveness of a fitness infusion instructional strategy (FI) on children's activity levels and skill performance scores. This strategy included aerobic activity within the skill practice tasks and game play. In other words, students performed short bouts of activity between the practice and…

  2. HEART RATE VARIABILITY AND 24-HOUR MINIMUM HEART RATE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heart rate variability (HRV) indices based on 24-hour electrocardiograph recordings have been used in clinical research studies to assess the aggregate activity of the autonomic nervous system. While 24-hour HRV is generally considered non-invasive, use in research protocols typically involves cons...

  3. Is Heart Rate a Norepiphenomenon in Heart Failure?

    PubMed

    Hensey, Mark; O'Neill, James

    2016-09-01

    There has been an increased focus on heart rate as a target in the management of cardiovascular disease and more specifically in heart failure with preserved ejection fraction in recent years with several studies showing the benefit of a lower resting heart rate on outcomes. This review paper examines the pathophysiology behind the benefits of lowering heart rate in heart failure and also the evidence for and against the pharmacological agents available to achieve this. PMID:27457085

  4. Evaluating the Ability of Heart Rate and EEG to Control Alertness during Performance

    NASA Technical Reports Server (NTRS)

    Freeman, Fred

    2002-01-01

    The major focus of the present proposal was to examine psychophysiological indices that show promise for invoking different modes of automation in an adaptive automation system. With the increased use of automation in today's work environment, people's roles in the work place are being redefined from that of active participant to one of passive monitor. Although the introduction of automated systems has a number of benefits, there are also a number of disadvantages regarding worker performance. Byrne and Parasuraman have argued for the use of psychophysiological measures in the development and the implementation of adaptive automation. While performance based, model based, and psychophysiologically based adaptive automation systems have been studied, the combined use of several psychophysiological measures has never been investigated. Such a combination provides the advantage of real time evaluation of the state of the subject in two relevant dimensions and offers a more realistic approach to the implementation of adaptive automation compared to the use of either dimension by itself.

  5. The contribution of coping-related variables and heart rate variability to visual search performance under pressure.

    PubMed

    Laborde, Sylvain; Lautenbach, Franziska; Allen, Mark S

    2015-02-01

    Visual search performance under pressure is explored within the predictions of the neurovisceral integration model. The experimental aims of this study were: 1) to investigate the contribution of coping-related variables to baseline, task, and reactivity (task-baseline) high-frequency heart rate variability (HF-HRV), and 2) to investigate the contribution of coping-related variables and HF-HRV to visual search performance under pressure. Participants (n=96) completed self-report measures of coping-related variables (emotional intelligence, coping style, perceived stress intensity, perceived control of stress, coping effectiveness, challenge and threat, and attention strategy) and HF-HRV was measured during a visual search task under pressure. The data show that baseline HF-HRV was predicted by a trait coping-related variable, task HF-HRV was predicted by a combination of trait and state coping-related variables, and reactivity HF-HRV was predicted by a state coping-related variable. Visual search performance was predicted by coping-related variables but not by HF-HRV. PMID:25481358

  6. Effects of In-Water Passive Recovery on Sprint Swimming Performance and Heart Rate in Adolescent Swimmers

    PubMed Central

    Casuso, Rafael A.; Martínez-López, Emilio; Hita-Contreras, Fidel; Ruiz-Cazalilla, Irene; Cruz-Díaz, David; Martínez-Amat, Antonio

    2014-01-01

    The aim of the present study is to test the hypothesis that sprint swimming performance is enhanced by in-water passive recovery (IN) after sprint swimming bouts in well-trained adolescent swimmers. Using a randomized crossover study design, twelve well-trained adolescent swimmers performed two tests at the swimming pool after preliminary testing. They performed 5 bouts of 100m all-out swimming separated by 5 minutes of passive rest. Their individual in- or out-of-water passive recovery condition was randomized on the first day. In their second visit to the swimming pool the opposite recovery condition was indicated. More than 60% of the subjects which rested in-water were faster in the 5th bout when compared to the OUT group. However, no significant differences were found in blood lactate when IN and OUT were compared. After the first bout peak heart rate (HR peak) was lower in subsequent bouts for IN recovery when compared with OUT (p < 0.001). Thus, coaches and researchers should take into account that IN passive recovery may decrease loss of performance and diminish HR peak during sprint swimming bouts. This is particularly important given the use that many coaches give to HR as a tool in daily training. Key points In-water passive recovery minimizes the loss of performance during high intensity swimming Maximal HR is significantly reduced by in-water recovery Coaches should take this information into account when using HR to control swimming intensity Future research should study long-term effects induced by in-water passive recovery PMID:25435791

  7. Resting Heart Rate and Auditory Evoked Potential

    PubMed Central

    Fiuza Regaçone, Simone; Baptista de Lima, Daiane Damaris; Engrácia Valenti, Vitor; Figueiredo Frizzo, Ana Cláudia

    2015-01-01

    The objective of this study was to evaluate the association between rest heart rate (HR) and the components of the auditory evoked-related potentials (ERPs) at rest in women. We investigated 21 healthy female university students between 18 and 24 years old. We performed complete audiological evaluation and measurement of heart rate for 10 minutes at rest (heart rate monitor Polar RS800CX) and performed ERPs analysis (discrepancy in frequency and duration). There was a moderate negative correlation of the N1 and P3a with rest HR and a strong positive correlation of the P2 and N2 components with rest HR. Larger components of the ERP are associated with higher rest HR. PMID:26504838

  8. Relationship of efficiency indices with performance, heart rate, oxygen consumption, blood parameters, and estimated heat production in Nellore steers.

    PubMed

    Chaves, A S; Nascimento, M L; Tullio, R R; Rosa, A N; Alencar, M M; Lanna, D P

    2015-10-01

    The objective of this study was to examine the relationship of efficiency indices with performance, heart rate, oxygen consumption, blood parameters, and estimated heat production (EHP) in Nellore steers. Eighteen steers were individually lot-fed diets of 2.7 Mcal ME/kg DM for 84 d. Estimated heat production was determined using oxygen pulse (OP) methodology, in which heart rate (HR) was monitored for 4 consecutive days. Oxygen pulse was obtained by simultaneously measuring HR and oxygen consumption during a 10- to 15-min period. Efficiency traits studied were feed efficiency (G:F) and residual feed intake (RFI) obtained by regression of DMI in relation to ADG and midtest metabolic BW (RFI). Alternatively, RFI was also obtained based on equations reported by the NRC's to estimate individual requirement and DMI (RFI calculated by the NRC [1996] equation [RFI]). The slope of the regression equation and its significance was used to evaluate the effect of efficiency indices (RFI, RFI, or G:F) on the traits studied. A mixed model was used considering RFI, RFI, or G:F and pen type as fixed effects and initial age as a covariate. For HR and EHP variables, day was included as a random effect. There was no relationship between efficiency indices and back fat depth measured by ultrasound or daily HR and EHP ( > 0.05). Because G:F is obtained in relation to BW, the slope of G:F was positive and significant ( < 0.05). Regardless of the method used, efficient steers had lower DMI ( < 0.05). The initial LM area was indirectly related to RFI and RFI ( < 0.05); however, the final muscle area was related to only RFI. Oxygen consumption per beat was not related to G:F; however, it was lower for RFI- and RFI-efficient steers, and consequently, oxygen volume (mL·min·kg) and OP (μL O·beat·kg) were also lower ( < 0.05). Blood parameters were not related to RFI and RFI ( > 0.05); however, G:F-efficient steers showed lower hematocrit and hemoglobin concentrations ( < 0

  9. Heart rate reduction in coronary artery disease and heart failure.

    PubMed

    Ferrari, Roberto; Fox, Kim

    2016-08-01

    Elevated heart rate is known to induce myocardial ischaemia in patients with coronary artery disease (CAD), and heart rate reduction is a recognized strategy to prevent ischaemic episodes. In addition, clinical evidence shows that slowing the heart rate reduces the symptoms of angina by improving microcirculation and coronary flow. Elevated heart rate is an established risk factor for cardiovascular events in patients with CAD and in those with chronic heart failure (HF). Accordingly, reducing heart rate improves prognosis in patients with HF, as demonstrated in SHIFT. By contrast, data from SIGNIFY indicate that heart rate is not a modifiable risk factor in patients with CAD who do not also have HF. Heart rate is also an important determinant of cardiac arrhythmias; low heart rate can be associated with atrial fibrillation, and high heart rate after exercise can be associated with sudden cardiac death. In this Review, we critically assess these clinical findings, and propose hypotheses for the variable effect of heart rate reduction in cardiovascular disease. PMID:27226153

  10. Heart rate deflection related to lactate performance curve and plasma catecholamine response during incremental cycle ergometer exercise.

    PubMed

    Pokan, R; Hofmann, P; Lehmann, M; Leitner, H; Eber, B; Gasser, R; Schwaberger, G; Schmid, P; Keul, J; Klein, W

    1995-01-01

    The correlation between the behaviour of the heart rate/work performance (fc/W) curve and blood lactate ([la]b) and plasma adrenaline/noradrenaline concentrations ([A]/[NA]) during incremental cycle ergometer exercise was investigated. A group of 21 male sports students was divided into two groups: group I, with a clear deflection of the fc/W curve; group II, without or with an inverse deflection of the fc/W curve. The aerobic threshold (Thaer) and the lactate turn point (LTP) were defined. Between Thaer and maximal work performance (Wmax) the behaviour of the fc/W curve as well as the behaviour of [la-]b and [A]. [NA] were described mathematically. The fc, systolic blood pressure (BPs), W, [la-]b, [A] and [NA] at rest, Thaer, LTP, Wmax, after 3 and 6 min of recovery (Re3/Re6) were calculated. A significant difference between the two groups could only be detected for fc at LTP, Re3 and Re6 (P < 0.05). No significant correlation could be found between individual fc/W-behaviour and individual time course of [la-]b, [A] and [NA]. However, a significant correlation was visible between [la-]b/W-behaviour and individual catecholamine response. These results and the fact that the different flattening at the top of the fc/W curve was related to diminished stress-dependent myocardial function led us to the conclusion that it is possible that sympathetic drive is not directly involved in mechanisms of regulation between load dependent fc and myocardial function. In addition, individual fc/W behaviour was independent of BPs and Wmax, or individual conditions of energy supply. PMID:7768241

  11. Multifractality and heart rate variability

    NASA Astrophysics Data System (ADS)

    Sassi, Roberto; Signorini, Maria Gabriella; Cerutti, Sergio

    2009-06-01

    In this paper, we participate to the discussion set forth by the editor of Chaos for the controversy, "Is the normal heart rate chaotic?" Our objective was to debate the question, "Is there some more appropriate term to characterize the heart rate variability (HRV) fluctuations?" We focused on the ≈24 h RR series prepared for this topic and tried to verify with two different techniques, generalized structure functions and wavelet transform modulus maxima, if they might be described as being multifractal. For normal and congestive heart failure subjects, the hq exponents showed to be decreasing for increasing q with both methods, as it should be for multifractal signals. We then built 40 surrogate series to further verify such hypothesis. For most of the series (≈75%-80% of cases) multifractality stood the test of the surrogate data employed. On the other hand, series coming from patients in atrial fibrillation showed a small, if any, degree of multifractality. The population analyzed is too small for definite conclusions, but the study supports the use of multifractal series to model HRV. Also it suggests that the regulatory action of autonomous nervous system might play a role in the observed multifractality.

  12. Wearable sensor for heart rate detection

    NASA Astrophysics Data System (ADS)

    Shi, Cong; Liu, Xiaohua; Kong, Lingqin; Wu, Jizhe; Liu, Ming; Dong, Liquan; Hui, Mei; Zhao, Yuejin

    2015-08-01

    In recent years heart and blood vessel diseases kill more people than everything else combined. The daily test of heart rate for the prevention and treatment of the heart head blood-vessel disease has the vital significance. In order to adapt the transformation of medical model and solve the low accuracy problem of the traditional method of heart rate measuring, we present a new method to monitor heart rate in this paper. The heart rate detection is designed for daily heart rate detection .The heart rate signal is collected by the heart rate sensor. The signal through signal processing circuits converts into sine wave and square wave in turn. And then the signal is transmitted to the computer by data collection card. Finally, we use LABVIEW and MATLAB to show the heart rate wave and calculate the heart rate. By doing contrast experiment with medical heart rate product, experimental results show that the system can realize rapidly and accurately measure the heart rate value. A measurement can be completed within 10 seconds and the error is less than 3beat/min. And the result shows that the method in this paper has a strong anti-interference ability. It can effectively suppress the movement interference. Beyond that the result is insensitive to light.

  13. How to Take Your Heart Rate

    MedlinePlus

    ... Page 1 of 2 The chart illustrates target heart rate ranges for exercise based on the maximal heart rate for selected ... to the next older age listed. - Compare your heart rate to the target exercise range. • If you are doing moderate exercise, your ...

  14. Heart rate detection from plantar bioimpedance measurements.

    PubMed

    González Landaeta, R; Casas, O; Pallàs-Areny, R

    2006-01-01

    The heart rate is a basic health indicator, useful in both clinical measurements and home health care. Current home care systems often require the attachment of electrodes or other sensors to the body, which can be cumbersome to the patient. Moreover, some measurements are sensitive to movement artifacts, are not user-friendly and require a specialized supervision. In this paper, a novel technique for heart rate measurement for a standing subject is proposed, which is based on plantar bioimpedance measurements, such as those performed by some bathroom weighting scales for body composition analysis. Because of the low level of heart-related impedance variations, the measurement system has a gain of 1400. We have implemented a fully differential AC amplifier with a common-mode rejection ratio (CMRR) of 105 dB at 10 kHz. Coherent demodulation based on synchronous sampling yields a signal-to-noise ratio (SNR) of 55 dB. The system has a sensitivity of 1.9 V/Omega. The technique has been demonstrated on 18 volunteers, whose bioimpedance signal and ECG were simultaneously measured to validate the results. The average cross-correlation coefficient between the heart rates determined from these two signals was 0.998 (std. dev. 0.001). PMID:17946677

  15. Assessing resting heart rate in adolescents: determinants and correlates.

    PubMed

    Rabbia, F; Grosso, T; Cat Genova, G; Conterno, A; De Vito, B; Mulatero, P; Chiandussi, L; Veglio, F

    2002-05-01

    The aim of this study was to evaluate the distribution of resting heart rate and its biological and environmental determinants in adolescents. The study was cross- sectional and the population consisted of 2230 children and adolescents, age range 12-18 years, enrolled randomly from state schools in Turin, Italy. In all participants the following parameters were evaluated: heart rate, blood pressure (BP), weight, height, degree of sexual development, physical activity, parental socio-cultural level. Heart rate and BP were measured after 5, 10 and 15 min in a sitting position. Furthermore, to obtain regression equations to define heart rate as a function of the other variables available, a multiple regression analysis was performed. In both sexes BP, but not heart rate, declined significantly from the first to the last determination. Heart rate was positively and significantly correlated to BP level in both sexes; heart rate was higher in girls (3 bpm) and followed a progressive decreasing trend with age in both sexes, that was opposite to BP values. Age, sexual maturation, height, physical activity and parental socio-cultural level were independent determinants of resting heart rate. In conclusion, resting heart rate in adolescents is related to several methodological, constitutional and environmental factors that have to be taken into account when assessing heart rate values and constructing tables of normal values. PMID:12082493

  16. Bluetooth Heart Rate Monitors For Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, R. E.; West, M. R.; Kalogera, K. L.; Hanson, A. M.

    2016-01-01

    Heart rate monitoring is required for crewmembers during exercise aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data are required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth heart rate monitors (BT_HRM) and their ability to provide high quality heart rate data to monitor crew health aboard the ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT_HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) were worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT_HRM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the 2 data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. RESULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6% error), followed by CS4 (3.3% error), CS3 (6.4% error), and CS2 (9.2% error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, but unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to obtain the best quality data. CS2 will be

  17. Bluetooth Heart Rate Monitors for Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, R. E.; West, M. R.; Kalogera, K. L.; Hanson, A. M.

    2016-01-01

    Heart rate monitoring is required for crewmembers during exercise aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data are required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth heart rate monitors (BT HRM) and their ability to provide high quality heart rate data to monitor crew health aboard the ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) were worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT HRM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the 2 data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. RESULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6% error), followed by CS4 (3.3% error), CS3 (6.4% error), and CS2 (9.2% error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, but unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to obtain the best quality data. CS2 will be

  18. Fetal heart rate classification using generative models.

    PubMed

    Dash, Shishir; Quirk, J Gerald; Djurić, Petar M

    2014-11-01

    This paper presents novel methods for classification of fetal heart rate (FHR) signals into categories that are meaningful for clinical implementation. They are based on generative models (GMs) and Bayesian theory. Instead of using scalar features that summarize information obtained from long-duration data, the models allow for explicit use of feature sequences derived from local patterns of FHR evolution. We compare our methods with a deterministic expert system for classification and with a support vector machine approach that relies on system-identification and heart rate variability features. We tested the classifiers on 83 retrospectively collected FHR records, with the gold-standard true diagnosis defined using umbilical cord pH values. We found that our methods consistently performed as well as or better than these, suggesting that the use of GMs and the Bayesian paradigm can bring significant improvement to automatic FHR classification approaches. PMID:24951678

  19. Acoustically based fetal heart rate monitor

    NASA Technical Reports Server (NTRS)

    Baker, Donald A.; Zuckerwar, Allan J.

    1991-01-01

    The acoustically based fetal heart rate monitor permits an expectant mother to perform the fetal Non-Stress Test in her home. The potential market would include the one million U.S. pregnancies per year requiring this type of prenatal surveillance. The monitor uses polyvinylidene fluoride (PVF2) piezoelectric polymer film for the acoustic sensors, which are mounted in a seven-element array on a cummerbund. Evaluation of the sensor ouput signals utilizes a digital signal processor, which performs a linear prediction routine in real time. Clinical tests reveal that the acoustically based monitor provides Non-Stress Test records which are comparable to those obtained with a commercial ultrasonic transducer.

  20. Heart-Rate and Breath-Rate Monitor

    NASA Technical Reports Server (NTRS)

    Cooper, T. G.

    1983-01-01

    Circuit requiring only four integrated circuits (IC's) measures both heart rate and breath rate. Phase-locked loops lock on heart-rate and respiration-rate input signals. Each loop IC contains two phase comparators. Positive-edge-triggered circuit used in making monitors insensitive to dutycycle variations.

  1. Heart Rate and Reinforcement Sensitivity in ADHD

    ERIC Educational Resources Information Center

    Luman, Marjolein; Oosterlaan, Jaap; Hyde, Christopher; van Meel, Catharina S.; Sergeant, Joseph A.

    2007-01-01

    Background: Both theoretical and clinical accounts of attention-deficit/hyperactivity disorder (ADHD) implicate a dysfunctional reinforcement system. This study investigated heart rate parameters in response to feedback associated with reward and response cost in ADHD children and controls aged 8 to 12. Methods: Heart rate responses (HRRs)…

  2. Volitional control of the heart rate.

    PubMed

    Abukonna, Ahmed; Yu, Xiaolin; Zhang, Chong; Zhang, Jianbao

    2013-11-01

    The heart rate is largely under control of the autonomic nervous system. The aim of the present study is to investigate the interactions between the brain and heart underlying volitional control of the heart and to explore the effectiveness of volition as a strategy to control the heart rate without biofeedback. Twenty seven healthy male subjects voluntarily participated in the study and were instructed to decrease and increase their heart beats according to rhythmic, computer generated sound either 10% faster or slower than the subjects' measured heart rate. Sympathetic and parasympathetic activities were estimated with the heart rate variability (HRV) obtained by power spectral analysis of RR intervals. Functional coupling patterns of cerebral cortex with the heart were determined by Partial directed coherence (PDC). In HR(slow) task; HR and sympathetic activity significantly decreased. However parasympathetic activity and power spectral density of EEG in low Alpha (8-10.5 Hz) band significantly increased. Moreover information flow from parietal area (P3 and P4) to RR interval significantly increased. During HR(quick) task; HR, sympathetic activity and power spectral density of EEG in low Beta (14-24 Hz) band significantly increased. Parasympathetic activity significantly decreased. Information flow from FT8, CZ and T8 electrodes to RR interval significantly increased. Our findings suggested that the heart beat can be controlled by volition and is related to some special areas in the cortex. PMID:23810994

  3. A New Approach to Detect Congestive Heart Failure Using Short-Term Heart Rate Variability Measures

    PubMed Central

    Wang, Qian; Zhou, GuangMin; Wang, Ying; Jiang, Qing

    2014-01-01

    Heart rate variability (HRV) analysis has quantified the functioning of the autonomic regulation of the heart and heart's ability to respond. However, majority of studies on HRV report several differences between patients with congestive heart failure (CHF) and healthy subjects, such as time-domain, frequency domain and nonlinear HRV measures. In the paper, we mainly presented a new approach to detect congestive heart failure (CHF) based on combination support vector machine (SVM) and three nonstandard heart rate variability (HRV) measures (e.g. SUM_TD, SUM_FD and SUM_IE). The CHF classification model was presented by using SVM classifier with the combination SUM_TD and SUM_FD. In the analysis performed, we found that the CHF classification algorithm could obtain the best performance with the CHF classification accuracy, sensitivity and specificity of 100%, 100%, 100%, respectively. PMID:24747432

  4. Heart Rate and Respiratory Rate Influence on Heart Rate Variability Repeatability: Effects of the Correction for the Prevailing Heart Rate

    PubMed Central

    Gąsior, Jakub S.; Sacha, Jerzy; Jeleń, Piotr J.; Zieliński, Jakub; Przybylski, Jacek

    2016-01-01

    Background: Since heart rate variability (HRV) is associated with average heart rate (HR) and respiratory rate (RespRate), alterations in these parameters may impose changes in HRV. Hence the repeatability of HRV measurements may be affected by differences in HR and RespRate. The study aimed to evaluate HRV repeatability and its association with changes in HR and RespRate. Methods: Forty healthy volunteers underwent two ECG examinations 7 days apart. Standard HRV indices were calculated from 5-min ECG recordings. The ECG-derived respiration signal was estimated to assess RespRate. To investigate HR impact on HRV, HRV parameters were corrected for prevailing HR. Results: Differences in HRV parameters between the measurements were associated with the changes in HR and RespRate. However, in multiple regression analysis only HR alteration proved to be independent determinant of the HRV differences—every change in HR by 1 bpm changed HRV values by 16.5% on average. After overall removal of HR impact on HRV, coefficients of variation of the HRV parameters significantly dropped on average by 26.8% (p < 0.001), i.e., by the same extent HRV reproducibility improved. Additionally, the HRV correction for HR decreased association between RespRate and HRV. Conclusions: In stable conditions, HR but not RespRate is the most powerful factor determining HRV reproducibility and even a minimal change of HR may considerably alter HRV. However, the removal of HR impact may significantly improve HRV repeatability. The association between HRV and RespRate seems to be, at least in part, HR dependent. PMID:27588006

  5. FPGA Implementation of Heart Rate Monitoring System.

    PubMed

    Panigrahy, D; Rakshit, M; Sahu, P K

    2016-03-01

    This paper describes a field programmable gate array (FPGA) implementation of a system that calculates the heart rate from Electrocardiogram (ECG) signal. After heart rate calculation, tachycardia, bradycardia or normal heart rate can easily be detected. ECG is a diagnosis tool routinely used to access the electrical activities and muscular function of the heart. Heart rate is calculated by detecting the R peaks from the ECG signal. To provide a portable and the continuous heart rate monitoring system for patients using ECG, needs a dedicated hardware. FPGA provides easy testability, allows faster implementation and verification option for implementing a new design. We have proposed a five-stage based methodology by using basic VHDL blocks like addition, multiplication and data conversion (real to the fixed point and vice-versa). Our proposed heart rate calculation (R-peak detection) method has been validated, using 48 first channel ECG records of the MIT-BIH arrhythmia database. It shows an accuracy of 99.84%, the sensitivity of 99.94% and the positive predictive value of 99.89%. Our proposed method outperforms other well-known methods in case of pathological ECG signals and successfully implemented in FPGA. PMID:26643079

  6. Effects of additional repeated sprint training during preseason on performance, heart rate variability, and stress symptoms in futsal players: a randomized controlled trial.

    PubMed

    Soares-Caldeira, Lúcio F; de Souza, Eberton A; de Freitas, Victor H; de Moraes, Solange M F; Leicht, Anthony S; Nakamura, Fábio Y

    2014-10-01

    The aim of this study was to investigate whether supplementing regular preseason futsal training with weekly sessions of repeated sprints (RS) training would have positive effects on repeated sprint ability (RSA) and field test performance. Thirteen players from a professional futsal team (22.6 ± 6.7 years, 72.8 ± 8.7 kg, 173.2 ± 6.2 cm) were divided randomly into 2 groups (AddT: n = 6 and normal training group: n = 7). Both groups performed a RSA test, Yo-Yo intermittent recovery test level 1 (YoYo IR1), squat (SJ) and countermovement jumps (CMJ), body composition, and heart rate variability (HRV) measures at rest before and after 4 weeks of preseason training. Athletes weekly stress symptoms were recorded by psychometric responses using the Daily Analysis of Life Demands for Athletes questionnaire and subjective ratings of well-being scale, respectively. The daily training load (arbitrary units) was assessed using the session of rating perceived exertion method. After the preseason training, there were no significant changes for body composition, SJ, CMJ, and RSAbest. The YoYo IR1, RSAmean, RSAworst, and RSAdecreament were significantly improved for both groups (p ≤ 0.05). The HRV parameters improved significantly within both groups (p ≤ 0.05) except for high frequency (HF, absolute and normalized units, [n.u.]), low frequency (LF) (n.u.), and the LF/HF ratio. A moderate effect size for the AddT group was observed for resting heart rate and several HRV measures. Training load and psychometric responses were similar between both groups. Additional RS training resulted in slightly greater positive changes for vagal-related HRV with similar improvements in performance and training stress during the preseason training in futsal players. PMID:24662230

  7. Fetal Heart Rate Monitoring during Labor

    MedlinePlus

    ... fetal heart rate. The other belt measures the length of contractions and the time between them. How ... uterus. Doppler Transducer: A device that uses sound waves to reflect motion—such as the fetal heartbeat— ...

  8. Heart rate indication using musical data.

    PubMed

    Yokoyama, Kiyoko; Ushida, Jun-ichiroh; Sugiura, Yasue; Mizuno, Mikako; Mizuno, Yasufumi; Takata, Kazuyuki

    2002-07-01

    Heart rate data reflects various physiological states such as biological workload, stress at work and concentration on tasks, drowsiness and the active state of the autonomic nervous system. This paper proposes system to indicate heart rate using musical data. Music changes physiological states for the better by relaxing people, or contributing to patient treatment through music therapy. Information in the form of music is advantageous because it does not hinder work as does verbal information and it contains more information than warning noises. We introduce and evaluate a prototype heart rate indication system and describe evaluation results of biofeedback effects on the worker during mental workload. The prototype system sequentially inputs the instantaneous heart rate into the computer, converts the data into musical instrument digital interface, the digital music format, and outputs it from the sound source. PMID:12083308

  9. Verification of the heart rate threshold.

    PubMed

    Bunc, V; Hofmann, P; Leitner, H; Gaisl, G

    1995-01-01

    Among the methods for determining anaerobic threshold (AT), the heart rate (HR) method seems to be the simplest. On the other hand, many conflicting results from comparing this method with others have been presented over the last 10 years. Therefore, the aim of this study was to compare the heart rate threshold (HRT) with the lactate turn point (LTP)-"second" break point of dependence of lactate (LA) to power output, ventilatory threshold (VT) and threshold determined by electromyography (EMGAT), all determined by the same exercise test and evaluated by the same computer algorithm. A group of 24 female students [mean age 20.5 (SD 1.6) years, maximal oxygen consumption 48.8 (SD 4.7) ml.kg-1.min-1] performed an incremental exercise test on a cycle ergometer (modified Conconi test) starting with an initial power output (PO) of 40 W with intensity increments of 10 W.min-1 until the subjects were exhausted. The HRT, LTP and EMGAT determination was done by computer-aided break-point regression analysis from dependence of functional measures on PO. The same computer algorithm was used for VT determination from the relationship between ventilation (V) and oxygen uptake (VO2) or carbon dioxide output (VCO2).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7607203

  10. Inverse Correlation between Heart Rate Variability and Heart Rate Demonstrated by Linear and Nonlinear Analysis.

    PubMed

    Kazmi, Syed Zaki Hassan; Zhang, Henggui; Aziz, Wajid; Monfredi, Oliver; Abbas, Syed Ali; Shah, Saeed Arif; Kazmi, Syeda Sobia Hassan; Butt, Wasi Haider

    2016-01-01

    The dynamical fluctuations in the rhythms of biological systems provide valuable information about the underlying functioning of these systems. During the past few decades analysis of cardiac function based on the heart rate variability (HRV; variation in R wave to R wave intervals) has attracted great attention, resulting in more than 17000-publications (PubMed list). However, it is still controversial about the underling mechanisms of HRV. In this study, we performed both linear (time domain and frequency domain) and nonlinear analysis of HRV data acquired from humans and animals to identify the relationship between HRV and heart rate (HR). The HRV data consists of the following groups: (a) human normal sinus rhythm (n = 72); (b) human congestive heart failure (n = 44); (c) rabbit sinoatrial node cells (SANC; n = 67); (d) conscious rat (n = 11). In both human and animal data at variant pathological conditions, both linear and nonlinear analysis techniques showed an inverse correlation between HRV and HR, supporting the concept that HRV is dependent on HR, and therefore, HRV cannot be used in an ordinary manner to analyse autonomic nerve activity of a heart. PMID:27336907

  11. Inverse Correlation between Heart Rate Variability and Heart Rate Demonstrated by Linear and Nonlinear Analysis

    PubMed Central

    Zhang, Henggui; Aziz, Wajid; Monfredi, Oliver; Abbas, Syed Ali; Shah, Saeed Arif; Kazmi, Syeda Sobia Hassan; Butt, Wasi Haider

    2016-01-01

    The dynamical fluctuations in the rhythms of biological systems provide valuable information about the underlying functioning of these systems. During the past few decades analysis of cardiac function based on the heart rate variability (HRV; variation in R wave to R wave intervals) has attracted great attention, resulting in more than 17000-publications (PubMed list). However, it is still controversial about the underling mechanisms of HRV. In this study, we performed both linear (time domain and frequency domain) and nonlinear analysis of HRV data acquired from humans and animals to identify the relationship between HRV and heart rate (HR). The HRV data consists of the following groups: (a) human normal sinus rhythm (n = 72); (b) human congestive heart failure (n = 44); (c) rabbit sinoatrial node cells (SANC; n = 67); (d) conscious rat (n = 11). In both human and animal data at variant pathological conditions, both linear and nonlinear analysis techniques showed an inverse correlation between HRV and HR, supporting the concept that HRV is dependent on HR, and therefore, HRV cannot be used in an ordinary manner to analyse autonomic nerve activity of a heart. PMID:27336907

  12. Elevated heart rate and nondipping heart rate as potential targets for melatonin: a review.

    PubMed

    Simko, Fedor; Baka, Tomas; Paulis, Ludovit; Reiter, Russel J

    2016-09-01

    Elevated heart rate is a risk factor for cardiovascular and all-cause mortalities in the general population and various cardiovascular pathologies. Insufficient heart rate decline during the night, that is, nondipping heart rate, also increases cardiovascular risk. Abnormal heart rate reflects an autonomic nervous system imbalance in terms of relative dominance of sympathetic tone. There are only a few prospective studies concerning the effect of heart rate reduction in coronary heart disease and heart failure. In hypertensive patients, retrospective analyses show no additional benefit of slowing down the heart rate by beta-blockade to blood pressure reduction. Melatonin, a secretory product of the pineal gland, has several attributes, which predict melatonin to be a promising candidate in the struggle against elevated heart rate and its consequences in the hypertensive population. First, melatonin production depends on the sympathetic stimulation of the pineal gland. On the other hand, melatonin inhibits the sympathetic system in several ways representing potentially the counter-regulatory mechanism to normalize excessive sympathetic drive. Second, administration of melatonin reduces heart rate in animals and humans. Third, the chronobiological action of melatonin may normalize the insufficient nocturnal decline of heart rate. Moreover, melatonin reduces the development of endothelial dysfunction and atherosclerosis, which are considered a crucial pathophysiological disorder of increased heart rate and pulsatile blood flow. The antihypertensive and antiremodeling action of melatonin along with its beneficial effects on lipid profile and insulin resistance may be of additional benefit. A clinical trial investigating melatonin actions in hypertensive patients with increased heart rate is warranted. PMID:27264986

  13. Heart Rate Sensor for Freshwater Mussels

    NASA Astrophysics Data System (ADS)

    Just, C. L.; Vial, D. P.; Kruger, A.; Niemeier, J. J.; Lee, H. W.; Schroer, H. W.

    2014-12-01

    Researchers have long been interested the cardiac activity of mollusks. First, it is important as a basic measure of the animal's metabolism. Further, activities such as feeding and burrowing affect heart rate, as do environmental factors such as water salinity, water temperature, exposure, and predation. We have developed a small, noninvasive sensor for measuring freshwater mussel heart rate. Its working principle is as follows. An infrared (IR) light-emitting diode is placed in contact with the mussel shell. Some of the IR penetrates through the shell, reflects off internal organs, and traverses back. A photodetector detects this IR, and electronics condition the signal. The heartbeat of the animal modulates the IR, allowing one to measure the heart rate. The technique is widely-used in finger heart-rate monitors in humans. The sensors do not have to be positioned above the heart and several locations on the mussel shell work well. The sensor is small (8 mm × 10 mm) and consumes less than 1 mA, and has a simple one-wire interface that allows for easy integration into data acquisition hardware. We present heart rate measurements for the common pocketbook (lampsilis cardium) freshwater mussel.

  14. Dynamic heart rate measurements from video sequences

    PubMed Central

    Yu, Yong-Poh; Raveendran, P.; Lim, Chern-Loon

    2015-01-01

    This paper shows how dynamic heart rate measurements that are typically obtained from sensors mounted near to the heart can also be obtained from video sequences. In this study, two experiments are carried out where a video camera captures the facial images of the seven subjects. The first experiment involves the measurement of subjects’ increasing heart rates (79 to 150 beats per minute (BPM)) while cycling whereas the second involves falling heart beats (153 to 88 BPM). In this study, independent component analysis (ICA) is combined with mutual information to ensure accuracy is not compromised in the use of short video duration. While both experiments are going on measures of heartbeat using the Polar heart rate monitor is also taken to compare with the findings of the proposed method. Overall experimental results show the proposed method can be used to measure dynamic heart rates where the root mean square error (RMSE) and the correlation coefficient are 1.88 BPM and 0.99 respectively. PMID:26203374

  15. Heart rate recovery and prognosis in heart failure patients

    PubMed Central

    Kubrychtova, Vera; Bailey, Kent R.; Thapa, Prabin; Allison, Thomas G.; Johnson, Bruce D.

    2009-01-01

    The aim of this study is to evaluate the usefulness of heart rate recovery (HRRec) for assessing risk of death in heart failure (HF) patients. Echocardiographic and clinical exercise data were analyzed retrospectively on 712 HF patients (EF ≤ 45%). HRRec was calculated as peak exercise heart rateheart rate at 1 min of active recovery. Patients were followed for all-cause mortality (5.9 ± 3.3 years follow-up). Groups were identified according to HRRec: group-1 (HRR ≤ 4 bpm), group-2 (5 ≤ HRR ≤ 9 bpm), and group-3 (HRR ≥ 10). Kaplan–Meier analysis estimated survival of 91, 64, and 43% (group-1); 94, 76, and 63% (group-2); and 92, 82, and 70% (group-3) at 1, 5, and 10 years, respectively. Ranked HRRec independently predicted mortality after adjusting for age, gender, NYHA class, LVEF and BMI, but was not independent of exercise time, peak VO2 and VE/VCO2 at nadir. HRRec is a useful prognostic marker in patients with HF, particularly when gas exchange measures are not available. PMID:18797918

  16. How Live Performance Moves the Human Heart.

    PubMed

    Shoda, Haruka; Adachi, Mayumi; Umeda, Tomohiro

    2016-01-01

    We investigated how the audience member's physiological reactions differ as a function of listening context (i.e., live versus recorded music contexts). Thirty-seven audience members were assigned to one of seven pianists' performances and listened to his/her live performances of six pieces (fast and slow pieces by Bach, Schumann, and Debussy). Approximately 10 weeks after the live performance, each of the audience members returned to the same room and listened to the recorded performances of the same pianists' via speakers. We recorded the audience members' electrocardiograms in listening to the performances in both conditions, and analyzed their heart rates and the spectral features of the heart-rate variability (i.e., HF/TF, LF/HF). Results showed that the audience's heart rate was higher for the faster than the slower piece only in the live condition. As compared with the recorded condition, the audience's sympathovagal balance (LF/HF) was less while their vagal nervous system (HF/TF) was activated more in the live condition, which appears to suggest that sharing the ongoing musical moments with the pianist reduces the audience's physiological stress. The results are discussed in terms of the audience's superior attention and temporal entrainment to live performance. PMID:27104377

  17. How Live Performance Moves the Human Heart

    PubMed Central

    Shoda, Haruka; Adachi, Mayumi; Umeda, Tomohiro

    2016-01-01

    We investigated how the audience member’s physiological reactions differ as a function of listening context (i.e., live versus recorded music contexts). Thirty-seven audience members were assigned to one of seven pianists’ performances and listened to his/her live performances of six pieces (fast and slow pieces by Bach, Schumann, and Debussy). Approximately 10 weeks after the live performance, each of the audience members returned to the same room and listened to the recorded performances of the same pianists’ via speakers. We recorded the audience members’ electrocardiograms in listening to the performances in both conditions, and analyzed their heart rates and the spectral features of the heart-rate variability (i.e., HF/TF, LF/HF). Results showed that the audience’s heart rate was higher for the faster than the slower piece only in the live condition. As compared with the recorded condition, the audience’s sympathovagal balance (LF/HF) was less while their vagal nervous system (HF/TF) was activated more in the live condition, which appears to suggest that sharing the ongoing musical moments with the pianist reduces the audience’s physiological stress. The results are discussed in terms of the audience’s superior attention and temporal entrainment to live performance. PMID:27104377

  18. [Hypoxaemia, peripheral chemoreceptors and fetal heart rate].

    PubMed

    Secourgeon, J-F

    2012-02-01

    The perinatal results of the widespread adoption of the continuous electronic fetal heart rate monitoring during labor remain rather disappointing. This is due in part to a lack of consistent interpretation of the fetal heart tracings. Despite efforts by referral agencies over the past decade the situation has not improved. In defense of practitioners the heterogeneity and complexity of definitions and classifications patterns especially morphological currently proposed should be noted. Whereas with the recent advances in the field of neuroscience, it is now possible to visualize the chain of pathophysiological events that lead from the hypoxemic stimulus of the glomus cell to changes in the morphology of the fetal heart rate tracing. Thus by taking some examples of real situations, we propose a method of analysis that dissects the fetal heart tracing and take into account the functional specifications of the chemoreceptor when exposed to a hypoxic environment. Furthermore we can identify tracings with a "threshold effect" and also "sensitization and desensitization effects" according to the intensity, duration and recurrence of hypoxaemic episodes. This new approach based upon specific research into the mechanism behind the fetal heart rate abnormalities may be useful to complement the morphological study of the fetal heart tracing, to provide a better idea of the fetal status and to better define the indications of fetal blood sampling procedures. PMID:21798673

  19. Heart-rate pulse-shift detector

    NASA Technical Reports Server (NTRS)

    Anderson, M.

    1974-01-01

    Detector circuit accurately separates and counts phase-shift pulses over wide range of basic pulse-rate frequency, and also provides reasonable representation of full repetitive EKG waveform. Single telemeter implanted in small animal monitors not only body temperature but also animal movement and heart rate.

  20. Heart to Heart: Using Heart Rate Telemetry to Meet Physical Education Outcomes.

    ERIC Educational Resources Information Center

    Deal, Tami Benham; Deal, Laurence O.

    1995-01-01

    Presents a foundation for establishing measurable physical education outcomes, demonstrating how heart rate telemetry can help measure and achieve such outcomes. After explaining heart rate telemetry function, the article examines student and teacher outcomes that could be included in school physical education outcomes and achieved using heart…

  1. Heart Rate Conditioning in Newborn Infants: Relationships Among Conditionability, Heart Rate Variability, and Sex

    ERIC Educational Resources Information Center

    Stamps, Leighton E.; Porges, Stephen W.

    1975-01-01

    Trace conditioning was evaluated in newborn infants by measurements of heart rate responses to a conditioned stimulus in anticipation of or in absence of the unconditioned stimulus. Data suggest females have higher levels of heart rate variability than males, which parallels their greater conditionability. (GO)

  2. The heart field effect: Synchronization of healer-subject heart rates in energy therapy.

    PubMed

    Bair, Christine Caldwell

    2008-01-01

    Recent health research has focused on subtle energy and vibrational frequency as key components of health and healing. In particular, intentional direction of bioenergy is receiving increasing scientific attention. This study investigates the effect of the healer's electromagnetic (EM) heart field upon subjects during energy healing as measured by synchronization of heart rates and scores on a Subjective Units of Distress (SUD) scale and a Profile of Mood States (POMS) inventory. A nonequivalent pretest-posttest design was used based on heart rate comparisons between healer and subject and correlated with pre-and posttest SUD and POMS scores. Subjects included those who sat within the 3- to 4-foot "strong" range of the independent variable, the healer's heart field, while performing self-application of WHEE (the wholistic hybrid derived from EMDR [eye movement desensitization and reprocessing], and EFT [emotional freedom technique]), a meridian-based tapping technique (n=50); and those who performed the same process beyond the 15- to 18-foot range of the healer's EM heart field (n=41). The dependent variables were heart rate, SUD, and POMS inventory. All subjects completed these measures within 1 hour. Study results showed statistically significant heart-rate synchronization with the intervention population. In addition, SUD and POMS scores demonstrated considerably more improvement than in the control population, indicating additional benefit beyond the meridian-based therapies, such as WHEE, alone. Additional findings and future research recommendations are presented in this article. PMID:20664147

  3. Effect of Short-Term Mobile Phone Base Station Exposure on Cognitive Performance, Body Temperature, Heart Rate and Blood Pressure of Malaysians.

    PubMed

    Malek, F; Rani, K A; Rahim, H A; Omar, M H

    2015-01-01

    Individuals who report their sensitivity to electromagnetic fields often undergo cognitive impairments that they believe are due to the exposure of mobile phone technology. The aim of this study is to clarify whether short-term exposure at 1 V/m to the typical Global System for Mobile Communication and Universal Mobile Telecommunications System (UMTS) affects cognitive performance and physiological parameters (body temperature, blood pressure and heart rate). This study applies counterbalanced randomizing single blind tests to determine if sensitive individuals experience more negative health effects when they are exposed to base station signals compared with sham (control) individuals. The sample size is 200 subjects with 50.0% Idiopathic Environmental Intolerance attributed to electromagnetic fields (IEI-EMF) also known as sensitive and 50.0% (non-IEI-EMF). The computer-administered Cambridge Neuropsychological Test Automated Battery (CANTAB eclipse(TM)) is used to examine cognitive performance. Four tests are chosen to evaluate Cognitive performance in CANTAB: Reaction Time (RTI), Rapid Visual Processing (RVP), Paired Associates Learning (PAL) and Spatial Span (SSP). Paired sample t-test on the other hand, is used to examine the physiological parameters. Generally, in both groups, there is no statistical significant difference between the exposure and sham exposure towards cognitive performance and physiological effects (P's > 0.05). PMID:26286015

  4. Effect of Short-Term Mobile Phone Base Station Exposure on Cognitive Performance, Body Temperature, Heart Rate and Blood Pressure of Malaysians

    PubMed Central

    Malek, F.; Rani, K. A.; Rahim, H. A.; Omar, M. H.

    2015-01-01

    Individuals who report their sensitivity to electromagnetic fields often undergo cognitive impairments that they believe are due to the exposure of mobile phone technology. The aim of this study is to clarify whether short-term exposure at 1 V/m to the typical Global System for Mobile Communication and Universal Mobile Telecommunications System (UMTS) affects cognitive performance and physiological parameters (body temperature, blood pressure and heart rate). This study applies counterbalanced randomizing single blind tests to determine if sensitive individuals experience more negative health effects when they are exposed to base station signals compared with sham (control) individuals. The sample size is 200 subjects with 50.0% Idiopathic Environmental Intolerance attributed to electromagnetic fields (IEI-EMF) also known as sensitive and 50.0% (non-IEI-EMF). The computer-administered Cambridge Neuropsychological Test Automated Battery (CANTAB eclipseTM) is used to examine cognitive performance. Four tests are chosen to evaluate Cognitive performance in CANTAB: Reaction Time (RTI), Rapid Visual Processing (RVP), Paired Associates Learning (PAL) and Spatial Span (SSP). Paired sample t-test on the other hand, is used to examine the physiological parameters. Generally, in both groups, there is no statistical significant difference between the exposure and sham exposure towards cognitive performance and physiological effects (P’s > 0.05). PMID:26286015

  5. Estimation of heart rate and heart rate variability from pulse oximeter recordings using localized model fitting.

    PubMed

    Wadehn, Federico; Carnal, David; Loeliger, Hans-Andrea

    2015-08-01

    Heart rate variability is one of the key parameters for assessing the health status of a subject's cardiovascular system. This paper presents a local model fitting algorithm used for finding single heart beats in photoplethysmogram recordings. The local fit of exponentially decaying cosines of frequencies within the physiological range is used to detect the presence of a heart beat. Using 42 subjects from the CapnoBase database, the average heart rate error was 0.16 BPM and the standard deviation of the absolute estimation error was 0.24 BPM. PMID:26737125

  6. Using photoplethysmography in heart rate monitoring of patients with epilepsy.

    PubMed

    van Andel, Judith; Ungureanu, Constantin; Aarts, Ronald; Leijten, Frans; Arends, Johan

    2015-04-01

    Heart rate is a useful neurophysiological sign when monitoring seizures in patients with epilepsy. In an ambulatory setting, heart rate is measured with ECG involving electrodes on the skin. This method is uncomfortable which is burdensome for patients and is sensitive to motion artifacts, which decrease the usability of measurements. In this study, green light photoplethysmography, an optical technique arising from the fitness industry, was evaluated for usefulness in a medical setting. Simultaneous overnight measurements of HR with a commercially available optical heart rate (OHR) sensor and with ECG (HRECG) were performed in 7 patients with epilepsy. Overall, there was no significant difference between OHR and HRECG in random 10-minute periods during wakefulness (p=0.69) and sleep (p=1.00). The Bland-Altman analysis showed negligible mean differences. Limits of agreement were higher during wakefulness and during the occurrence of two seizures possibly because of less reliable HRECG measurements due to motion artifacts. Optical heart rate seems less sensitive to these motion artifacts, and measurements are more user-friendly. The optical heart rate sensor may fill the gap of systems for ambulatory heart rate monitoring and can be especially useful in the context of seizure detection in patients with epilepsy. PMID:25812938

  7. Accuracy of Heart Rate Watches: Implications for Weight Management

    PubMed Central

    2016-01-01

    Background Wrist-worn monitors claim to provide accurate measures of heart rate and energy expenditure. People wishing to lose weight use these devices to monitor energy balance, however the accuracy of these devices to measure such parameters has not been established. Aim To determine the accuracy of four wrist-worn devices (Apple Watch, Fitbit Charge HR, Samsung Gear S and Mio Alpha) to measure heart rate and energy expenditure at rest and during exercise. Methods Twenty-two healthy volunteers (50% female; aged 24 ± 5.6 years) completed ~1-hr protocols involving supine and seated rest, walking and running on a treadmill and cycling on an ergometer. Data from the devices collected during the protocol were compared with reference methods: electrocardiography (heart rate) and indirect calorimetry (energy expenditure). Results None of the devices performed significantly better overall, however heart rate was consistently more accurate than energy expenditure across all four devices. Correlations between the devices and reference methods were moderate to strong for heart rate (0.67–0.95 [0.35 to 0.98]) and weak to strong for energy expenditure (0.16–0.86 [-0.25 to 0.95]). All devices underestimated both outcomes compared to reference methods. The percentage error for heart rate was small across the devices (range: 1–9%) but greater for energy expenditure (9–43%). Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm) than energy expenditure (ranging from -266.7 to 65.7 kcals) across devices. Conclusion These devices accurately measure heart rate. However, estimates of energy expenditure are poor and would have implications for people using these devices for weight loss. PMID:27232714

  8. Age differences in high frequency phasic heart rate variability and performance response to increased executive function load in three executive function tasks

    PubMed Central

    Byrd, Dana L.; Reuther, Erin T.; McNamara, Joseph P. H.; DeLucca, Teri L.; Berg, William K.

    2015-01-01

    The current study examines similarity or disparity of a frontally mediated physiological response of mental effort among multiple executive functioning tasks between children and adults. Task performance and phasic heart rate variability (HRV) were recorded in children (6 to 10 years old) and adults in an examination of age differences in executive functioning skills during periods of increased demand. Executive load levels were varied by increasing the difficulty levels of three executive functioning tasks: inhibition (IN), working memory (WM), and planning/problem solving (PL). Behavioral performance decreased in all tasks with increased executive demand in both children and adults. Adults’ phasic high frequency HRV was suppressed during the management of increased IN and WM load. Children’s phasic HRV was suppressed during the management of moderate WM load. HRV was not suppressed during either children’s or adults’ increasing load during the PL task. High frequency phasic HRV may be most sensitive to executive function tasks that have a time-response pressure, and simply requiring performance on a self-paced task requiring frontal lobe activation may not be enough to generate HRV responsitivity to increasing demand. PMID:25798113

  9. Current clinical applications of heart rate variability.

    PubMed

    Stys, A; Stys, T

    1998-10-01

    Heart rate variability (HRV) has become a popular method for the studies of physiologic mechanisms responsible for the control of heart rate fluctuations, in which the autonomic nervous system appears to play a primary role. Depression of HRV has been observed in many clinical scenarios, including autonomic neuropathy, heart transplantation, congestive heart failure, myocardial infarction (MI), and other cardiac and noncardiac diseases. However, it is important to realize that clinical implication of HRV analysis has been clearly recognized in only two clinical conditions: (1) as a predictor of risk of arrhythmic events or sudden cardiac death after acute MI, and (2) as a clinical marker of evolving diabetic neuropathy. Recently, its role in evaluation and management of heart failure has also been recognized. It is pertinent to recognize the limitations of HRV as far as its clinical utility at present is concerned. The methodology of HRV had remained poorly standardized until the recent publication of the Special Report of the Task Force of ESC/NASPE, and thus has been presenting difficulty in comparing earlier existing data. Also, determination of the exact sensitivity, specificity, and predictive value of HRV, as well as the normal values of standard measures in the general population, still require further investigation before better standards can be set for existing and future clinical applications. This article reviews the major concepts of HRV measurements, their clinical relevance, and the recent advances in this field. PMID:9789691

  10. Influence of Rest Interval Length Between Sets on Blood Pressure and Heart Rate Variability After a Strength Training Session Performed By Prehypertensive Men.

    PubMed

    Figueiredo, Tiago; Willardson, Jeffrey M; Miranda, Humberto; Bentes, Claudio M; Machado Reis, Victor; Freitas de Salles, Belmiro; Simão, Roberto

    2016-07-01

    Figueiredo, T, Willardson, JM, Miranda, H, Bentes, CM, Machado Reis, V, Freitas de Salles, B, and Simão, R. Influence of rest interval length between sets on blood pressure and heart rate variability after a strength training session performed by prehypertensive men. J Strength Cond Res 30(7): 1813-1824, 2016-The purposes of this study were to compare the effects of 2 different rest interval lengths between sets and exercises during strength training (ST) on blood pressure (BP) and heart rate variability (HRV) in prehypertensive trained men, and to verify how HRV influences BP. Eleven volunteer subjects (age: 26.1 ± 3.6 years; body mass: 74.1 ± 7.9 kg; height: 172.1 ± 4.1 cm; % body fat: 18.3 ± 6.3; ST experience: 1.7 ± 0.8 years) participated in this study. After assessing one repetition maximum (1RM) loads for the free weight bench press, lat pull-down, shoulder press, biceps curl, triceps extension, leg press, leg extension, and leg curl exercises; subjects performed 2 sessions with different rest intervals between sets and exercises in random order and 72 hours apart. Each ST session consisted of performing 3 sets of eight to 10 repetitions at 70% of a 1RM for each exercise, with either 1-minute (sequence 1 [SEQ1]) or 2-minute (sequence 2 [SEQ2]) rest intervals between sets and exercises, respectively. Before and after each session, BP and HRV (low frequency band, high frequency [HF] band, and square root of the mean squared difference of successive RR-interval index) were tracked for 60 minutes. The results demonstrated a postexercise hypotensive response (PEH) after both rest interval conditions (p ≤ 0.05). Additionally, increases in cardiac stress were noted after SEQ1, with a greater withdrawal in parasympathetic activity vs. baseline as noted in the HF band at 1-, 10-, and 20-minute postexercise (p ≤ 0.05). These results indicate that both sequences provided an effective stimulus for a PEH. Therefore, strength and conditioning professionals may

  11. Heart Rate and Lactate Levels during Weight-Training Exercise in Trained and Untrained Men.

    ERIC Educational Resources Information Center

    Stone, Michael H.; And Others

    1987-01-01

    A study of effects of squatting exercise on heart rate and blood lactate levels in trained and untrained males indicated that trained subjects performed more work and had higher heart rates and lactate levels at exhaustion untrained subjects, though heart rate and lactate levels were lower for trained subjects at a given bar mass or submaximal…

  12. Lessons from the Heart: Individualizing Physical Education with Heart Rate Monitors.

    ERIC Educational Resources Information Center

    Kirkpatrick, Beth; Birnbaum, Burton H.

    Learning about the relationship between heart rate and physical activity is an important aspect of fitness education. Use of a heart rate monitor (HRM) helps a student to understand how stretching and large muscle movements gradually increase the heart rate and blood flow, and enables students to measure their exercise heart rates and set goals…

  13. Gaussian Mixture Model of Heart Rate Variability

    PubMed Central

    Costa, Tommaso; Boccignone, Giuseppe; Ferraro, Mario

    2012-01-01

    Heart rate variability (HRV) is an important measure of sympathetic and parasympathetic functions of the autonomic nervous system and a key indicator of cardiovascular condition. This paper proposes a novel method to investigate HRV, namely by modelling it as a linear combination of Gaussians. Results show that three Gaussians are enough to describe the stationary statistics of heart variability and to provide a straightforward interpretation of the HRV power spectrum. Comparisons have been made also with synthetic data generated from different physiologically based models showing the plausibility of the Gaussian mixture parameters. PMID:22666386

  14. Effects of different training amplitudes on heart rate and heart rate variability in young rowers.

    PubMed

    Vaz, Marcelo S; Picanço, Luan M; Del Vecchio, Fabrício B

    2014-10-01

    The aim of this study was to investigate the autonomic nervous system recovery and the psychological response as a result of 3 training amplitudes on heart rate (HR), heart rate variability (HRV), and rate of perceived exertion (RPE) in rowing. Eight young rowers (16.8 ± 1.4 years) performed, in a randomized fashion, 2 sessions of high-intensity interval training, with high and low amplitude and a continuous training (CT) session, with the same exercise duration (10 minutes) and mean intensity (60% of maximal stroke test). The data of HR, HRV, and RPE were collected 5 minutes before, immediately after each session, and 24 hours later. High amplitude promoted higher impact in maximum HR (p ≤ 0.05) and RPE (p < 0.001) when compared with CT. For the time domain HRV variable, there was a statistically significant difference between moments of rest (pretraining or post 24 hours) and posttraining in all training sessions. Originally, we conclude that training with higher load variation between effort and recovery impacts HRV, HR, and RPE with greater intensity, but the younger rowers were ready for new training sessions 24 hours after either training method. Coaches can use the polarized training method, observing the stimulus nature and time required for recovery, because it may be an adequate strategy for the development of rower's conditioning. PMID:24736775

  15. Determination of Anaerobic Threshold by Heart Rate or Heart Rate Variability using Discontinuous Cycle Ergometry

    PubMed Central

    PARK, SUNG WOOK; BRENNEMAN, MICHAEL; COOKE, WILLIAM H.; CORDOVA, ALBERTO; FOGT, DONOVAN

    2014-01-01

    The purpose was to determine if heart rate (HR) and heart rate variability (HRV) responses would reflect anaerobic threshold (AT) using a discontinuous, incremental, cycle test. AT was determined by ventilatory threshold (VT). Cyclists (30.6±5.9y; 7 males, 8 females) completed a discontinuous cycle test consisting of 7 stages (6 min each with 3 min of rest between). Three stages were performed at power outputs (W) below those corresponding to a previously established AT, one at W corresponding to AT, and 3 at W above those corresponding to AT. The W at the intersection of the trend lines was considered each metric’s “threshold”. The averaged stage data for Ve, HR, and time- and frequency-domain HRV metrics were plotted versus W. The W at the “threshold” for the metrics of interest were compared using correlation analysis and paired-sample t-test. In all, several heart rate-related parameters accurately reflected AT with significant correlations (p≤0.05) were observed between AT W and HR, mean RR interval (MRR), low and high frequency spectral energy (LF and HR, respectively), high frequency peak (fHF), and HFxfHF metrics’ threshold W (i.e., MRRTW, etc.). Differences in HR or HRV metric threshold W and AT for all subjects were less than 14 W. The steady state data from discontinuous protocols may allow for a true indication of steady-state physiologic stress responses and corresponding W at AT, compared to continuous protocols using 1–2 min exercise stages. PMID:27182400

  16. AUTONOMIC CONTROL OF HEART RATE AFTER EXERCISE IN TRAINED WRESTLERS

    PubMed Central

    Báez, San Martín E.; Von Oetinger, A.; Cañas, Jamett R.; Ramírez, Campillo R.

    2013-01-01

    The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability – SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR60s (p <0.05) and in the non linear analysis of HRV from SD130-45s (p <0.05) and SD145-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW. PMID:24744476

  17. Autonomic control of heart rate after exercise in trained wrestlers.

    PubMed

    Henríquez, Olguín C; Báez, San Martín E; Von Oetinger, A; Cañas, Jamett R; Ramírez, Campillo R

    2013-06-01

    The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability - SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR60s (p <0.05) and in the non linear analysis of HRV from SD130-45s (p <0.05) and SD145-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW. PMID:24744476

  18. Investigation of determinism in heart rate variability

    NASA Astrophysics Data System (ADS)

    Gomes, M. E. D.; Souza, A. V. P.; Guimarães, H. N.; Aguirre, L. A.

    2000-06-01

    The article searches for the possible presence of determinism in heart rate variability (HRV) signals by using a new approach based on NARMA (nonlinear autoregressive moving average) modeling and free-run prediction. Thirty-three 256-point HRV time series obtained from Wistar rats submitted to different autonomic blockade protocols are considered, and a collection of surrogate data sets are generated from each one of them. These surrogate sequences are assumed to be nondeterministic and therefore they may not be predictable. The original HRV time series and related surrogates are submitted to NARMA modeling and prediction. Special attention has been paid to the problem of stationarity. The results consistently show that the surrogate data sets cannot be predicted better than the trivial predictor—the mean—while most of the HRV control sequences are predictable to a certain degree. This suggests that the normal HRV signals have a deterministic signature. The HRV time series derived from the autonomic blockade segments of the experimental protocols do not show the same predictability performance, albeit the physiological interpretation is not obvious. These results have important implications to the methodology of HRV analysis, indicating that techniques from nonlinear dynamics and deterministic chaos may be applied to elicit more information about the autonomic modulation of the cardiovascular activity.

  19. Analysis of Heart Rate and Heart Rate Variation During Cardiac CT Examinations

    PubMed Central

    Zhang, Jie; Fletcher, Joel G.; Harmsen, W. Scott; Araoz, Philip A.; Williamson, Eric E.; Primak, Andrew N.; McCollough, Cynthia H.

    2009-01-01

    Rationale and Objectives We sought to examine heart rate and heart rate variability during cardiac computed tomography (CT). Materials and Methods Ninety patients (59.0 ± 13.5 years) underwent coronary CT angiography (CTA), with 52 patients also undergoing coronary artery calcium scanning (CAC). Forty-two patients with heart rate greater than 70 bpm were pretreated with oral β-blockers (in five patients, use of β-blocker was not known). Sixty-four patients were given sublingual nitroglycerin. Mean heart rate and percentage of beats outside a ±5 bpm region about the mean were compared between baseline (free breathing), prescan hyperventilation, and scan acquisition (breath-hold). Results Mean scan acquisition time was 13.1 ± 1.5 seconds for CAC scanning and 14.2 ± 2.9 seconds for coronary CTA. Mean heart rate during scan acquisition was significantly lower than at baseline (CAC 58.2 ± 8.5 bpm; CTA 59.2 ± 8.8 bpm; baseline 62.8 ± 8.9 bpm; P < .001). The percentage of beats outside a ±5 bpm about the mean were not different between baseline and CTA scanning (3.5% versus 3.3%, P = .87). The injection of contrast had no significant effect on heart rate (58.2 bpm versus 59.2 bpm, P = .24) or percentage of beats outside a ±5 bpm about the mean (3.0% versus 3.3%, P = .64). No significant difference was found between gender and age groups (P > .05). Conclusions Breath-holding during cardiac CT scan acquisition significantly lowers the mean heart rate by approximately 4 bpm, but heart rate variability is the same or less compared with normal breathing. PMID:18078905

  20. Heart Rate Variability – A Historical Perspective

    PubMed Central

    Billman, George E.

    2011-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R–R interval – the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration – the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of HRV. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the “Physician’s Pulse Watch” (a watch with a second hand that could be stopped) in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733) was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895) and advent of digital signal processing techniques in the 1960s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations) that are commonly used to measure HRV. PMID:22144961

  1. Heart rate variability - a historical perspective.

    PubMed

    Billman, George E

    2011-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R-R interval - the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration - the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of HRV. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the "Physician's Pulse Watch" (a watch with a second hand that could be stopped) in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733) was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895) and advent of digital signal processing techniques in the 1960s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations) that are commonly used to measure HRV. PMID:22144961

  2. Modeling heart rate variability by stochastic feedback

    NASA Technical Reports Server (NTRS)

    Amaral, L. A.; Goldberger, A. L.; Stanley, H. E.

    1999-01-01

    We consider the question of how the cardiac rhythm spontaneously self-regulates and propose a new mechanism as a possible answer. We model the neuroautonomic regulation of the heart rate as a stochastic feedback system and find that the model successfully accounts for key characteristics of cardiac variability, including the 1/f power spectrum, the functional form and scaling of the distribution of variations of the interbeat intervals, and the correlations in the Fourier phases which indicate nonlinear dynamics.

  3. Multiscale power analysis for heart rate variability

    NASA Astrophysics Data System (ADS)

    Zeng, Peng; Liu, Hongxing; Ni, Huangjing; Zhou, Jing; Xia, Lan; Ning, Xinbao

    2015-06-01

    We first introduce multiscale power (MSP) method to assess the power distribution of physiological signals on multiple time scales. Simulation on synthetic data and experiments on heart rate variability (HRV) are tested to support the approach. Results show that both physical and psychological changes influence power distribution significantly. A quantitative parameter, termed power difference (PD), is introduced to evaluate the degree of power distribution alteration. We find that dynamical correlation of HRV will be destroyed completely when PD>0.7.

  4. Neuroanatomical substrates for the volitional regulation of heart rate.

    PubMed

    Jones, Catherine L; Minati, Ludovico; Nagai, Yoko; Medford, Nick; Harrison, Neil A; Gray, Marcus; Ward, Jamie; Critchley, Hugo D

    2015-01-01

    The control of physiological arousal can assist in the regulation of emotional state. A subset cortical and subcortical brain regions are implicated in autonomic control of bodily arousal during emotional behaviors. Here, we combined human functional neuroimaging with autonomic monitoring to identify neural mechanisms that support the volitional regulation of heart rate, a process that may be assisted by visual feedback. During functional magnetic resonance imaging (fMRI), 15 healthy adults performed an experimental task in which they were prompted voluntarily to increase or decrease cardiovascular arousal (heart rate) during true, false, or absent visual feedback. Participants achieved appropriate changes in heart rate, without significant modulation of respiratory rate, and were overall not influenced by the presence of visual feedback. Increased activity in right amygdala, striatum and brainstem occurred when participants attempted to increase heart rate. In contrast, activation of ventrolateral prefrontal and parietal cortices occurred when attempting to decrease heart rate. Biofeedback enhanced activity within occipito-temporal cortices, but there was no significant interaction with task conditions. Activity in regions including pregenual anterior cingulate and ventral striatum reflected the magnitude of successful task performance, which was negatively related to subclinical anxiety symptoms. Measured changes in respiration correlated with posterior insula activation and heart rate, at a more lenient threshold, change correlated with insula, caudate, and midbrain activity. Our findings highlight a set of brain regions, notably ventrolateral prefrontal cortex, supporting volitional control of cardiovascular arousal. These data are relevant to understanding neural substrates supporting interaction between intentional and interoceptive states related to anxiety, with implications for biofeedback interventions, e.g., real-time fMRI, that target emotional

  5. Unobtrusive heart rate monitor based on a fiber specklegram sensor and a single-board computer

    NASA Astrophysics Data System (ADS)

    Benevides, Alessandro B.; Frizera, Anselmo; Cotrina, Anibal; Ribeiro, Moisés. R. N.; Segatto, Marcelo E. V.; Pontes, Maria José

    2015-09-01

    This paper proposes a portable and unobtrusive heart rate monitor based on fiber specklegram sensors. The proposed module uses the Raspberry Pi module to perform the image acquisition and the fiber specklegram sensor, which is based on multimode plastic optical fibers. The heart rate is obtained by welch power spectral density estimate and the heart beats are identified by means of a threshold analysis.

  6. Passive fetal heart rate monitoring apparatus and method with enhanced fetal heart beat discrimination

    NASA Technical Reports Server (NTRS)

    Zahorian, Stephen A. (Inventor); Livingston, David L. (Inventor); Pretlow, III, Robert A. (Inventor)

    1996-01-01

    An apparatus for acquiring signals emitted by a fetus, identifying fetal heart beats and determining a fetal heart rate. Multiple sensor signals are outputted by a passive fetal heart rate monitoring sensor. Multiple parallel nonlinear filters filter these multiple sensor signals to identify fetal heart beats in the signal data. A processor determines a fetal heart rate based on these identified fetal heart beats. The processor includes the use of a figure of merit weighting of heart rate estimates based on the identified heart beats from each filter for each signal. The fetal heart rate thus determined is outputted to a display, storage, or communications channel. A method for enhanced fetal heart beat discrimination includes acquiring signals from a fetus, identifying fetal heart beats from the signals by multiple parallel nonlinear filtering, and determining a fetal heart rate based on the identified fetal heart beats. A figure of merit operation in this method provides for weighting a plurality of fetal heart rate estimates based on the identified fetal heart beats and selecting the highest ranking fetal heart rate estimate.

  7. The mitochondrial uniporter controls fight or flight heart rate increases

    PubMed Central

    Wu, Yuejin; Rasmussen, Tyler P.; Koval, Olha M.; Joiner, Mei-ling A.; Hall, Duane D.; Chen, Biyi; Luczak, Elizabeth D.; Wang, Qiongling; Rokita, Adam G.; Wehrens, Xander H. T.; Song, Longsheng; Anderson, Mark E.

    2015-01-01

    Heart rate increases are a fundamental adaptation to physiological stress, while inappropriate heart rate increases are resistant to current therapies. However, the metabolic mechanisms driving heart rate acceleration in cardiac pacemaker cells remain incompletely understood. The mitochondrial calcium uniporter (MCU) facilitates calcium entry into the mitochondrial matrix to stimulate metabolism. We developed mice with myocardial MCU inhibition by transgenic expression of a dominant negative (DN) MCU. Here we show that DN-MCU mice had normal resting heart rates but were incapable of physiological fight or flight heart rate acceleration. We found MCU function was essential for rapidly increasing mitochondrial calcium in pacemaker cells and that MCU enhanced oxidative phoshorylation was required to accelerate reloading of an intracellular calcium compartment prior to each heartbeat. Our findings show the MCU is necessary for complete physiological heart rate acceleration and suggest MCU inhibition could reduce inappropriate heart rate increases without affecting resting heart rate. PMID:25603276

  8. BIOPHYSICAL CHARACTERISATION OF THE UNDER-APPRECIATED AND IMPORTANT RELATIONSHIP BETWEEN HEART RATE VARIABILITY AND HEART RATE

    PubMed Central

    Monfredi, Oliver; Lyashkov, Alexey E; Johnsen, Anne-Berit; Inada, Shin; Schneider, Heiko; Wang, Ruoxi; Nirmalan, Mahesh; Wisloff, Ulrik; Maltsev, Victor A; Lakatta, Edward G; Zhang, Henggui; Boyett, Mark R

    2014-01-01

    Heart rate variability (beat-to-beat changes in the RR interval) has attracted considerable attention over the last 30+ years (PubMed currently lists >17,000 publications). Clinically, a decrease in heart rate variability is correlated to higher morbidity and mortality in diverse conditions, from heart disease to foetal distress. It is usually attributed to fluctuation in cardiac autonomic nerve activity. We calculated heart rate variability parameters from a variety of cardiac preparations (including humans, living animals, Langendorff-perfused heart and single sinoatrial nodal cell) in diverse species, combining this with data from previously published papers. We show that regardless of conditions, there is a universal exponential decay-like relationship between heart rate variability and heart rate. Using two biophysical models, we develop a theory for this, and confirm that heart rate variability is primarily dependent on heart rate and cannot be used in any simple way to assess autonomic nerve activity to the heart. We suggest that the correlation between a change in heart rate variability and altered morbidity and mortality is substantially attributable to the concurrent change in heart rate. This calls for re-evaluation of the findings from many papers that have not adjusted properly or at all for heart rate differences when comparing heart rate variability in multiple circumstances. PMID:25225208

  9. A healthy heart is not a metronome: an integrative review of the heart's anatomy and heart rate variability

    PubMed Central

    Shaffer, Fred; McCraty, Rollin; Zerr, Christopher L.

    2014-01-01

    Heart rate variability (HRV), the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operate on different time scales to adapt to challenges and achieve optimal performance. This article briefly reviews neural regulation of the heart, and its basic anatomy, the cardiac cycle, and the sinoatrial and atrioventricular pacemakers. The cardiovascular regulation center in the medulla integrates sensory information and input from higher brain centers, and afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. This article reviews sympathetic and parasympathetic influences on the heart, and examines the interpretation of HRV and the association between reduced HRV, risk of disease and mortality, and the loss of regulatory capacity. This article also discusses the intrinsic cardiac nervous system and the heart-brain connection, through which afferent information can influence activity in the subcortical and frontocortical areas, and motor cortex. It also considers new perspectives on the putative underlying physiological mechanisms and properties of the ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands. Additionally, it reviews the most common time and frequency domain measurements as well as standardized data collection protocols. In its final section, this article integrates Porges' polyvagal theory, Thayer and colleagues' neurovisceral integration model, Lehrer et al.'s resonance frequency model, and the Institute of HeartMath's coherence model. The authors conclude that a coherent heart is not a metronome because its rhythms are characterized by both complexity and stability over longer time scales. Future research should expand understanding of how the heart and its intrinsic nervous system influence the brain. PMID:25324790

  10. A comparison between heart rate and heart rate variability as indicators of cardiac health and fitness.

    PubMed

    Grant, Catharina C; Murray, Carien; Janse van Rensburg, Dina C; Fletcher, Lizelle

    2013-01-01

    Quantification of cardiac autonomic activity and control via heart rate (HR) and heart rate variability (HRV) is known to provide prognostic information in clinical populations. Issues with regard to standardization and interpretation of HRV data make the use of the more easily accessible HR on its own as an indicator of autonomic cardiac control very appealing. The aim of this study was to investigate the strength of associations between an important cardio vascular health metric such as VO2max and the following: HR, HRV indicators, and HR normalized HRV indicators. A cross sectional descriptive study was done including 145 healthy volunteers aged between 18 and 22 years. HRV was quantified by time domain, frequency domain and Poincaré plot analysis. Indirect VO2max was determined using the Multistage Coopers test. The Pearson correlation coefficient was calculated to quantify the strength of the associations. Both simple linear and multiple stepwise regressions were performed to be able to discriminate between the role of the individual indicators as well as their combined association with VO2max. Only HR, RR interval, and pNN50 showed significant (p < 0.01, p < 0.01, and p = 0.03) correlations with VO2max. Stepwise multiple regression indicated that, when combining all HRV indicators the most important predictor of cardio vascular fitness as represented by VO2max, is HR. HR explains 17% of the variation, while the inclusion of HF (high frequency HRV indicator) added only an additional 3.1% to the coefficient of determination. Results also showed when testing the normalized indicators, HR explained of the largest percentage of the changes in VO2max (16.5%). Thus, HR on its own is the most important predictor of changes in an important cardiac health metric such as VO2max. These results may indicate that during investigation of exercise ability (VO2max) phenomena, quantification of HRV may not add significant value. PMID:24312058

  11. Interaction Between Heart Rate Variability and Heart Rate in Pediatric Population

    PubMed Central

    Gąsior, Jakub S.; Sacha, Jerzy; Jeleń, Piotr J.; Pawłowski, Mariusz; Werner, Bożena; Dąbrowski, Marek J.

    2015-01-01

    Background: Heart rate variability (HRV) is primarily heart rate (HR) dependent, and therefore, different HR may exert different impact on HRV. The objectives of the study were to evaluate the effect of HR on HRV in children and to determine whether HRV indices normalized to HR are sex- and age-related. Methods: Short-term ECG recordings were performed in 346 healthy children. Standard time and frequency domain HRV parameters and HR were analyzed in four age subgroups (6–7, 8–9, 10–11, and 12–13 years old). To investigate the HR impact on HRV, standard HRV parameters were normalized to prevailing HR. Results: Standard HRV measures did not differ between age subgroups, however, HR significantly decreased with subjects age and turned out to be the strongest determinant of HRV. The normalization of HRV to prevailing HR allowed to show that sex-related differences in standard HRV resulted from differences in HR between boys and girls. The normalized HRV significantly decreased with age—before the normalization this effect was masked by age-related HR alterations. Conclusions: HR significantly impacts HRV in pediatric population and turns out to be the strongest determinant of all standard HRV indices. The differences in standard HRV between boys and girls result from differences in their HR. The normalized HRV is decreasing with age in healthy children and it is accompanied by the reduction of HR—as a net result, the standard HRV is constant in children at different ages. This may reflect the maturation of the autonomic nervous system. PMID:26733878

  12. Wavelet and receiver operating characteristic analysis of heart rate variability

    NASA Astrophysics Data System (ADS)

    McCaffery, G.; Griffith, T. M.; Naka, K.; Frennaux, M. P.; Matthai, C. C.

    2002-02-01

    Multiresolution wavelet analysis has been used to study the heart rate variability in two classes of patients with different pathological conditions. The scale dependent measure of Thurner et al. was found to be statistically significant in discriminating patients suffering from hypercardiomyopathy from a control set of normal subjects. We have performed Receiver Operating Characteristc (ROC) analysis and found the ROC area to be a useful measure by which to label the significance of the discrimination, as well as to describe the severity of heart dysfunction.

  13. Heart rate variability in free diving athletes.

    PubMed

    Christoforidi, Vassiliki; Koutlianos, Nikolaos; Deligiannis, Pantazis; Kouidi, Evangelia; Deligiannis, Asterios

    2012-03-01

    The aim of the study was to evaluate the cardiac autonomic activity in free diving (FD) athletes. Thirteen Greek male free divers (group I, aged 33.4 ± 6.3 years, 6.6 ± 4.5 years of training experience) volunteered to participate while 13 age-matched sedentary subjects served as control group (group II). All subjects were submitted to ambulatory 24-h ECG recording for heart rate variability (HRV) analysis on a day of regular activities with no exercise or training. The results showed that group I had significantly lower minimum and mean heart rate by 23.9% (P < 0.001) and 20.6% (P < 0.001), respectively. All the measured time and frequency domain indices of HRV which reflect cardiac parasympathetic activity were higher in group I than in group II by 37.6% to 146% (P < 0.001). Conclusively, the resting cardiac autonomic activity and especially the parasympathetic branch was significantly increased in free divers compared to untrained subjects. This finding should be rather attributed to the accumulated effect of both exercise training and frequent exposure to FD stimulus. PMID:22296638

  14. Vaginal intercourse frequency and heart rate variability.

    PubMed

    Brody, Stuart; Preut, Ragnar

    2003-01-01

    We examined the relationship between recalled and diary recorded frequency of penile-vaginal intercourse (FSI) and both resting heart rate variability (HRV; an index of cardiac autonomic control and parasympathetic tone associated with cardiovascular health outcomes) and resting diastolic blood pressure (DBP) in 120 healthy adults aged 19-38 (subjects scoring above the 87th percentile on the Lie scale of the Eysenck Personality Inventory were excluded from analyses). As in a previous smaller study, greater HRV was associated with greater FSI (but not masturbation or non-coital sex with a partner) and rated importance of intercourse. There were no sex differences in the HRV-FSI relationship, and the relationship was not explained by including measures of Extraversion, Neuroticism, Depression, Trait Anxiety, or partnership satisfaction. However, the previously obtained negative association of FSI with DBP was not replicated. PMID:14504008

  15. Renyi entropy measures of heart rate Gaussianity.

    PubMed

    Lake, Douglas E

    2006-01-01

    Sample entropy and approximate entropy are measures that have been successfully utilized to study the deterministic dynamics of heart rate (HR). A complementary stochastic point of view and a heuristic argument using the Central Limit Theorem suggests that the Gaussianity of HR is a complementary measure of the physiological complexity of the underlying signal transduction processes. Renyi entropy (or q-entropy) is a widely used measure of Gaussianity in many applications. Particularly important members of this family are differential (or Shannon) entropy (q = 1) and quadratic entropy (q = 2). We introduce the concepts of differential and conditional Renyi entropy rate and, in conjunction with Burg's theorem, develop a measure of the Gaussianity of a linear random process. Robust algorithms for estimating these quantities are presented along with estimates of their standard errors. PMID:16402599

  16. A PC-aided optical foetal heart rate detection system.

    PubMed

    Oweis, Rami J; As'ad, Hala; Aldarawsheh, Amany; Al-Khdeirat, Rawan; Lwissy, Kaldoun

    2014-01-01

    Safe monitoring of foetal heart rate is a valuable tool for the healthy evolution and wellbeing of both foetus and mother. This paper presents a non-invasive optical technique that allows for foetal heart rate detection using a photovoltaic infrared (IR) detector placed on the mother's abdomen. The system presented here consists of a photoplethysmography (PPG) circuit, abdomen circuit and a personal computer equipped with MATLAB. A near IR beam having a wavelength of 880 nm is transmitted through the mother's abdomen and foetal tissue. The received abdominal signal that conveys information pertaining to the mother and foetal heart rate is sensed by a low noise photodetector. The PC receives the signal through the National Instrumentation Data Acquisition Card (NIDAQ). After synchronous detection of the abdominal and finger PPG signals, the designed MATLAB-based software saves, analyses and extracts information related to the foetal heart rate. Extraction is carried out using recursive least squares adaptive filtration. Measurements on eight pregnant women with gestational periods ranging from 35-39 weeks were performed using the proposed system and CTG. Results show a correlation coefficient of 0.978 and a correlation confidence interval between 88-99.6%. The t test results in a p value of 0.034, which is less than 0.05. Low power, low cost, high signal-to-noise ratio, reduction of ambient light effect and ease of use are the main characteristics of the proposed system. PMID:24195701

  17. Adaptation of autonomic heart rate regulation in astronauts after spaceflight

    PubMed Central

    Vandeput, Steven; Widjaja, Devy; Aubert, Andre E.; Van Huffel, Sabine

    2013-01-01

    Background Spaceflight causes changes in the cardiovascular control system. The aim of this study was to evaluate postflight recovery of linear and nonlinear neural markers of heart rate modulation, with a special focus on day-night variations. Material/Methods Twenty-four-hour Holter ECG recordings were obtained in 8 astronauts participating in space missions aboard the International Space Station (ISS). Data recording was performed 1 month before launch, and 5 and 30 days after return to Earth from short- and long-term flights. Cardiovascular control was inferred from linear and nonlinear heart rate variability (HRV) parameters, separately during 2-hour day and 2-hour night recordings. Results No remarkable differences were found in the postflight recovery between astronauts from short- and long-duration spaceflights. Five days after return to Earth, vagal modulation was significantly decreased compared to the preflight condition (day: p=0.001; night: p=0.019), while the sympathovagal balance was strongly increased, but only at night (p=0.017). A few nonlinear parameters were reduced early postflight compared to preflight values, but these were not always statistically significant. No significant differences remained after 30 days of postflight recovery. Conclusions Our results show that 5 days after return from both short- and long-duration space missions, neural mechanisms of heart rate regulation are still disturbed. After 1 month, autonomic control of heart rate recovered almost completely. PMID:23291736

  18. Comparison of heart rate responses. Water walking versus treadmill walking.

    PubMed

    Whitley, J D; Schoene, L L

    1987-10-01

    The purpose of this study was to compare heart rate responses to water walking versus treadmill walking to determine whether the responses were of sufficient magnitude to elicit cardiorespiratory training effects. The heart rates of 12 healthy, female college students were measured immediately after walking in waist-deep water and on a treadmill at the same distance, durations, and speeds (2.55, 2.77, 3.02, and 3.31 km/hr). A significant increase in heart rate with increased speeds resulted from water walking (p less than .05); from rest to the fastest speed, it was 135% (96 bpm). For treadmill walking, the increase of 19% (13 bpm) was not significant. The heart rates for the water condition were significantly higher (p less than .05) at each speed. These findings indicate that water walking could serve as an effective exercise mode, for example, for cardiorespiratory fitness for individuals who are unable to perform such weight-bearing activities as jogging, fast walking, cycling, and dancing. PMID:3659133

  19. Aerobic Fitness, Heart Rate Recovery and Heart Rate Recovery Time in Indian School Children.

    PubMed

    Fernando, Rajesh Jeniton; Ravichandran, K; Vaz, Mario

    2015-01-01

    Data on aerobic fitness and heart rate recovery in children are limited. This study was done to evaluate the relation between them in Indian school going children. Three hundred children of 7 to 10.5 years were recruited and their aerobic fitness was predicted using modified Harvard's step test (VO₂max) and 20 meter shuttle test (VO₂peak). The heart rate was monitored for 12 minutes post modified Harvard's step test. The difference between the maximum and the 1st minute HR was noted as HRR1 and the time taken to reach the resting heart rate was also recorded. VO₂max was inversely correlated with HRR1 (r = -0.64, p<0.001). However, the partial correlation of the two was not significant (r(partial) = -0.037, p = 0.55), indicating children with higher basal HR had higher HRR1 and that accounted for the observed association with aerobic fitness. Cox regression analysis showed that the recovery rate per unit time was 3% greater with increasing VO₂max (HR = 1.03, 95% CI:1.01 to 1.05, p = 0.013). The heart rate parameters did not show any associat with VO₂peak This study demonstrates that there is no relation between VO₂max and HRR1 after 3 minutes of modified Harvard's step test in Indian children of 7 to 10.5 years. However, aerobic fitness is a positive predictor of heart rate recovery time in this group. PMID:27530008

  20. A Performance of the Heart

    ERIC Educational Resources Information Center

    Williams, Joan; McCauley, Joyce; Grumble, Melissa

    2013-01-01

    How the heart works is found in "A Framework for K-12 Science Education" and connects to Life Sciences Core and Component Ideas, From Molecules to Organisms: Structures and Processes (NRC 2012). By the end of grade 2, students should understand that all organisms have external parts, which they use in various ways to seek, find, and take…

  1. The heart rate VO2 relationship of aerobic dance: a comparison of target heart rate methods.

    PubMed

    Scharff-Olson, M; Williford, H N; Smith, F H

    1992-12-01

    The purpose of this study was to examine the relationship between heart rate (HR) and oxygen consumption (VO2) for aerobic dance exercise. Therefore, eleven females completed 20 minutes of aerobic dance with continuous monitoring of HR and VO2. These physiological responses were analyzed with correlation/regression techniques. The results showed that for aerobic dance to produce a response in excess of 50% of VO2 max, the target HR must be approximately 80% of the age-predicted HR max or greater. In contrast, previously reported data for treadmill running shows that 50% of VO2 max is achieved at approximately 65% of age-predicted HR max in females. The maximum heart rate reserve (Karvonen) method was also found to underestimate the actual VO2 of AD. With the Karvonen method, the target heart rate must approximate 65% of maximum HR reserve in order to elicit a VO2 response which is representative of 50% of VO2 max. These data support recent research which illustrates that target heart rate prescriptions derived from treadmill testing may fail to accurately place AD participants in the recommended training zone. PMID:1293420

  2. Music structure determines heart rate variability of singers.

    PubMed

    Vickhoff, Björn; Malmgren, Helge; Aström, Rickard; Nyberg, Gunnar; Ekström, Seth-Reino; Engwall, Mathias; Snygg, Johan; Nilsson, Michael; Jörnsten, Rebecka

    2013-01-01

    Choir singing is known to promote wellbeing. One reason for this may be that singing demands a slower than normal respiration, which may in turn affect heart activity. Coupling of heart rate variability (HRV) to respiration is called Respiratory sinus arrhythmia (RSA). This coupling has a subjective as well as a biologically soothing effect, and it is beneficial for cardiovascular function. RSA is seen to be more marked during slow-paced breathing and at lower respiration rates (0.1 Hz and below). In this study, we investigate how singing, which is a form of guided breathing, affects HRV and RSA. The study comprises a group of healthy 18 year olds of mixed gender. The subjects are asked to; (1) hum a single tone and breathe whenever they need to; (2) sing a hymn with free, unguided breathing; and (3) sing a slow mantra and breathe solely between phrases. Heart rate (HR) is measured continuously during the study. The study design makes it possible to compare above three levels of song structure. In a separate case study, we examine five individuals performing singing tasks (1-3). We collect data with more advanced equipment, simultaneously recording HR, respiration, skin conductance and finger temperature. We show how song structure, respiration and HR are connected. Unison singing of regular song structures makes the hearts of the singers accelerate and decelerate simultaneously. Implications concerning the effect on wellbeing and health are discussed as well as the question how this inner entrainment may affect perception and behavior. PMID:23847555

  3. Procedural pain heart rate responses in massaged preterm infants.

    PubMed

    Diego, Miguel A; Field, Tiffany; Hernandez-Reif, Maria

    2009-04-01

    Heart rate (HR) responses to the removal of a monitoring lead were assessed in 56 preterm infants who received moderate pressure, light pressure or no massage therapy. The infants who received moderate pressure massage therapy exhibited lower increases in HR suggesting an attenuated pain response. The heart rate of infants who received moderate pressure massage also returned to baseline faster than the heart rate of the other two groups, suggesting a faster recovery rate. PMID:19185352

  4. Ordinal pattern statistics for the assessment of heart rate variability

    NASA Astrophysics Data System (ADS)

    Graff, G.; Graff, B.; Kaczkowska, A.; Makowiec, D.; Amigó, J. M.; Piskorski, J.; Narkiewicz, K.; Guzik, P.

    2013-06-01

    The recognition of all main features of a healthy heart rhythm (the so-called sinus rhythm) is still one of the biggest challenges in contemporary cardiology. Recently the interesting physiological phenomenon of heart rate asymmetry has been observed. This phenomenon is related to unbalanced contributions of heart rate decelerations and accelerations to heart rate variability. In this paper we apply methods based on the concept of ordinal pattern to the analysis of electrocardiograms (inter-peak intervals) of healthy subjects in the supine position. This way we observe new regularities of the heart rhythm related to the distribution of ordinal patterns of lengths 3 and 4.

  5. Harmonic relationship between preferred tempi and heart rate.

    PubMed

    Iwanaga, M

    1995-08-01

    Since people tend to prefer musical tempi ranging from 70 to 100 beats per minute, cyclic physiological response like heart rate is considered on of the factors affected by tempo preference. The present study aimed to examine the relationship between preferred tempi and heart rate. Subjects were instructed to find their favorite tempi while their hart rates were being measured. The presented tone stimulus was 440 Hz, 60 dB pressure of pure tone, and the presented tempo varied from 10 to 300 cycles per minute. The relationship between heart rate and preferred tempo was examined to calculate the density function of ratios of preferred tempi to heart rate. This density function indicated that preferred tempi were distributed mostly one, one and a half, and two times as fast as heart rate. This finding indicated preferred tempi had a simple harmonic relationship to heart rate. PMID:8532483

  6. Classifying work rate from heart rate measurements using an adaptive neuro-fuzzy inference system.

    PubMed

    Kolus, Ahmet; Imbeau, Daniel; Dubé, Philippe-Antoine; Dubeau, Denise

    2016-05-01

    In a new approach based on adaptive neuro-fuzzy inference systems (ANFIS), field heart rate (HR) measurements were used to classify work rate into four categories: very light, light, moderate, and heavy. Inter-participant variability (physiological and physical differences) was considered. Twenty-eight participants performed Meyer and Flenghi's step-test and a maximal treadmill test, during which heart rate and oxygen consumption (VO2) were measured. Results indicated that heart rate monitoring (HR, HRmax, and HRrest) and body weight are significant variables for classifying work rate. The ANFIS classifier showed superior sensitivity, specificity, and accuracy compared to current practice using established work rate categories based on percent heart rate reserve (%HRR). The ANFIS classifier showed an overall 29.6% difference in classification accuracy and a good balance between sensitivity (90.7%) and specificity (95.2%) on average. With its ease of implementation and variable measurement, the ANFIS classifier shows potential for widespread use by practitioners for work rate assessment. PMID:26851475

  7. Bluetooth(Registered Trademark) Heart Rate Monitors for Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, Roxanne E.; West, Michael R.; Kalogera, Kent L.; Hanson, Andrea M.

    2016-01-01

    Heart rate monitoring is required during exercise for crewmembers aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data is required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth® heart rate monitors (BT_HRM) and their ability to provide high quality heart rate data to monitor crew health on board ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT_HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) was worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT_RHM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the two data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. REULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6%error), followed by CS4 (3.3%error), CS3 (6.4%error), and CS2 (9.2%error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to get the best quality data. CS2 will be used in an

  8. Heart rate dynamics preceding hemorrhage in the intensive care unit.

    PubMed

    Moss, Travis J; Clark, Matthew T; Lake, Douglas E; Moorman, J Randall; Calland, J Forrest

    2015-01-01

    Occult hemorrhage in surgical/trauma intensive care unit (STICU) patients is common and may lead to circulatory collapse. Continuous electrocardiography (ECG) monitoring may allow for early identification and treatment, and could improve outcomes. We studied 4,259 consecutive admissions to the STICU at the University of Virginia Health System. We collected ECG waveform data captured by bedside monitors and calculated linear and non-linear measures of the RR interbeat intervals. We tested the hypothesis that a transfusion requirement of 3 or more PRBC transfusions in a 24 hour period is preceded by dynamical changes in these heart rate measures and performed logistic regression modeling. We identified 308 hemorrhage events. A multivariate model including heart rate, standard deviation of the RR intervals, detrended fluctuation analysis, and local dynamics density had a C-statistic of 0.62. Earlier detection of hemorrhage might improve outcomes by allowing earlier resuscitation in STICU patients. PMID:26342251

  9. Qigong Effects on Heart Rate Variability and Peripheral Vasomotor Responses.

    PubMed

    Chang, Mei-Ying

    2015-11-01

    Population aging is occurring worldwide, and preventing cardiovascular event in older people is a unique challenge. The aim of this study was to examine the effects of a 12-week qigong (eight-form moving meditation) training program on the heart rate variability and peripheral vasomotor response of middle-aged and elderly people in the community. This was a quasi-experimental study that included the pre-test, post-test, and nonequivalent control group designs. Seventy-seven participants (experimental group = 47; control group = 30) were recruited. The experimental group performed 30 min of eight-form moving meditation 3 times per week for 12 weeks, and the control group continued their normal daily activities. After 12 weeks, the interaction effects indicated that compared with the control group, the experimental group exhibited significantly improved heart rate variability and peripheral vasomotor responses. PMID:24869492

  10. The precision and accuracy of a portable heart rate monitor.

    PubMed

    Seaward, B L; Sleamaker, R H; McAuliffe, T; Clapp, J F

    1990-01-01

    A device that would comfortably and accurately measure exercise heart rate during field performance could be valuable for athletes, fitness participants, and investigators in the field of exercise physiology. Such a device, a portable telemeterized microprocessor, was compared with direct EKG measurements in a laboratory setting under several conditions to assess its accuracy. Twenty-four subjects were studied at rest and during light-, moderate-, high-, and maximal-intensity endurance activities (walking, running, aerobic dancing, and Nordic Track simulated cross-country skiing. Differences between values obtained by the two measuring devices were not statistically significant, with correlation coefficient (r) values ranging from 0.998 to 0.999. The two methods proved equally reliable for measuring heart rate in a host of varied aerobic activities at varying intensities. PMID:2306564

  11. gHRV: Heart rate variability analysis made easy.

    PubMed

    Rodríguez-Liñares, L; Lado, M J; Vila, X A; Méndez, A J; Cuesta, P

    2014-08-01

    In this paper, the gHRV software tool is presented. It is a simple, free and portable tool developed in python for analysing heart rate variability. It includes a graphical user interface and it can import files in multiple formats, analyse time intervals in the signal, test statistical significance and export the results. This paper also contains, as an example of use, a clinical analysis performed with the gHRV tool, namely to determine whether the heart rate variability indexes change across different stages of sleep. Results from tests completed by researchers who have tried gHRV are also explained: in general the application was positively valued and results reflect a high level of satisfaction. gHRV is in continuous development and new versions will include suggestions made by testers. PMID:24854108

  12. Monitoring of heart and respiratory rates by photoplethysmography using a digital filtering technique.

    PubMed

    Nakajima, K; Tamura, T; Miike, H

    1996-07-01

    An apparatus for simultaneously monitoring heart and respiratory rates was developed using photoplethysmography (PPG) and digital filters, and compared with conventional methods. The PPG signal, which includes both heart and respiratory components, was measured at the earlobe with an original transmission mode photoplethysmographic device. A digital filtering technique was used to distinguish heart and respiratory signals from the PPG signal. The cut-off frequency of the respiratory signal filter was selected automatically depending on the heart rate. Using digital filtering techniques, heart and respiratory signals were separated at rest and during exercise. The digital signal processor was employed to realize an adaptive and real-time filtering. The heart rate was calculated by the zero-crossing method and the respiratory rate from the peak interval of the filtered signal. To evaluate the newly developed monitor, an ECG for heart rate and a transthoracic impedance plethysmogram for respiratory rate were monitored simultaneously. To obtain higher heart and respiratory rates, exercise was performed on an electrical bicycle ergometer. Heart and respiratory rates calculated by the new method compare to those obtained from ECG and the transthoracic impedance plethysmogram. The maximum error of heart and respiratory rates was 10 beats/min and 7 breaths/min, respectively. PMID:8818134

  13. Controlling the emotional heart: heart rate biofeedback improves cardiac control during emotional reactions.

    PubMed

    Peira, Nathalie; Fredrikson, Mats; Pourtois, Gilles

    2014-03-01

    When regulating negative emotional reactions, one goal is to reduce physiological reactions. However, not all regulation strategies succeed in doing that. We tested whether heart rate biofeedback helped participants reduce physiological reactions in response to negative and neutral pictures. When viewing neutral pictures, participants could regulate their heart rate whether the heart rate feedback was real or not. In contrast, when viewing negative pictures, participants could regulate heart rate only when feedback was real. Ratings of task success paralleled heart rate. Participants' general level of anxiety, emotion awareness, or cognitive emotion regulation strategies did not influence the results. Our findings show that accurate online heart rate biofeedback provides an efficient way to down-regulate autonomic physiological reactions when encountering negative stimuli. PMID:24373886

  14. Unconstrained Evaluation System for Heart Rate Using Ultrasonic Vibrograph

    NASA Astrophysics Data System (ADS)

    Nagamune, Kouki; Kobashi, Syoji; Kondo, Katsuya; Hata, Yutaka; Taniguchi, Kazuhiko; Sawayama, Toshiyuki

    2004-05-01

    Unconstrained health monitoring systems have received much considerable attention in medical applications, because such system can examine a subject without constraint. In this study, we propose a detection method based on a fuzzy logic for evaluating heart rate using our ultrasonic vibrograph. In the experiment for confirming heart rate, our method has been successfully used to detect the heart rates of four subjects, compared with a method using an electrocardiograph.

  15. Dissociation of heart rate variability and heart rate recovery in well-trained athletes.

    PubMed

    Lee, C Matthew; Mendoza, Albert

    2012-07-01

    The purpose of this investigation was to examine the relationships between aerobic fitness, volume of physical activity (PA), heart rate variability (HRV), and heart rate recovery (HRR) in a group of well-trained endurance athletes. Nineteen endurance athletes participated in this study and had aerobic capacities that placed them above the 99th percentile based on normative values (VO(2max): 67.1 ± 2 ml kg(-1) min(-1)). HRV was obtained via an EKG collected during supine rest and reported as high-frequency (HF), low-frequency (LF), and total power (TP). Natural log (ln) transformation was applied when variables violated assumptions of normality. HRR recovery was reported as the reduction in heart rate from peak exercise to the heart rate 1 min after cessation of exercise and PA was estimated from a questionnaire. HRR was significantly correlated with PA and VO(2max) (r = 0.67, P = 0.003 and 0.51, P = 0.039, respectively), but not with any index of HRV. Age was significantly correlated with lnHF (r = -0.49, P = 0.033), lnLF/lnHF (r = 0.48, P = 0.037), and normalized units (NU) of LF (r = 0.47, P = 0.042) and HF (r = -0.47, P = 0.042). Stepwise regression revealed that the strongest predictor of HRR was PA (R (2) = 0.45) and that VO(2max) did not add significant predictive value to the model. The relationship between HRV and age is evident in well-trained endurance athletes, whereas the relationship between HRV and PA/aerobic fitness is not. The maintained relationship between HRR and PA/aerobic fitness suggests that HRR may be a better marker of fitness-related differences in autonomic control in this population. PMID:22124525

  16. A Bayesian classification of heart rate variability data

    NASA Astrophysics Data System (ADS)

    Muirhead, R. J.; Puff, R. D.

    2004-05-01

    We propose a simple Bayesian method for the classification of time series signals originating from mutually exclusive sources. In particular, the method is used to address the question of whether a 24-h recording of human heart rate data is produced by a normally functioning heart or by one exhibiting symptoms of congestive heart failure. Our method correctly classifies 18 of 18 normal heart data sets, and 38 of 44 congestive failure data sets.

  17. Biophysical characterization of the underappreciated and important relationship between heart rate variability and heart rate.

    PubMed

    Monfredi, Oliver; Lyashkov, Alexey E; Johnsen, Anne-Berit; Inada, Shin; Schneider, Heiko; Wang, Ruoxi; Nirmalan, Mahesh; Wisloff, Ulrik; Maltsev, Victor A; Lakatta, Edward G; Zhang, Henggui; Boyett, Mark R

    2014-12-01

    Heart rate (HR) variability (HRV; beat-to-beat changes in the R-wave to R-wave interval) has attracted considerable attention during the past 30+ years (PubMed currently lists >17 000 publications). Clinically, a decrease in HRV is correlated to higher morbidity and mortality in diverse conditions, from heart disease to fetal distress. It is usually attributed to fluctuation in cardiac autonomic nerve activity. We calculated HRV parameters from a variety of cardiac preparations (including humans, living animals, Langendorff-perfused heart, and single sinoatrial nodal cell) in diverse species, combining this with data from previously published articles. We show that regardless of conditions, there is a universal exponential decay-like relationship between HRV and HR. Using 2 biophysical models, we develop a theory for this and confirm that HRV is primarily dependent on HR and cannot be used in any simple way to assess autonomic nerve activity to the heart. We suggest that the correlation between a change in HRV and altered morbidity and mortality is substantially attributable to the concurrent change in HR. This calls for re-evaluation of the findings from many articles that have not adjusted properly or at all for HR differences when comparing HRV in multiple circumstances. PMID:25225208

  18. Critical Scale Invariance in a Healthy Human Heart Rate

    NASA Astrophysics Data System (ADS)

    Kiyono, Ken; Struzik, Zbigniew R.; Aoyagi, Naoko; Sakata, Seiichiro; Hayano, Junichiro; Yamamoto, Yoshiharu

    2004-10-01

    We demonstrate the robust scale-invariance in the probability density function (PDF) of detrended healthy human heart rate increments, which is preserved not only in a quiescent condition, but also in a dynamic state where the mean level of the heart rate is dramatically changing. This scale-independent and fractal structure is markedly different from the scale-dependent PDF evolution observed in a turbulentlike, cascade heart rate model. These results strongly support the view that a healthy human heart rate is controlled to converge continually to a critical state.

  19. Heart rate variability and suicidal behavior.

    PubMed

    Wilson, Scott T; Chesin, Megan; Fertuck, Eric; Keilp, John; Brodsky, Beth; Mann, J John; Sönmez, Cemile Ceren; Benjamin-Phillips, Christopher; Stanley, Barbara

    2016-06-30

    Identification of biological indicators of suicide risk is important given advantages of biomarker-based models. Decreased high frequency heart rate variability (HF HRV) may be a biomarker of suicide risk. The aim of this research was to determine whether HF HRV differs between suicide attempters and non-attempters. Using the Trier Social Stress Test (TSST), we compared HF HRV between females with and without a history of suicide attempt, all with a lifetime diagnosis of a mood disorder. To investigate a potential mechanism explaining association between HF HRV and suicide, we examined the association between self-reported anger and HF HRV. Results of an Area under the Curve (AUC) analysis showed attempters had a lower cumulative HF HRV during the TSST than non-attempters. In addition, while there was no difference in self-reported anger at baseline, the increase in anger was greater in attempters, and negatively associated with HF HRV. Results suggest that suicide attempters have a reduced capacity to regulate their response to stress, and that reduced capacity to regulate anger may be a mechanism through which decreased HF HRV can lead to an increase in suicide risk. Our results have implications for the prevention of suicidal behavior in at-risk populations. PMID:27124209

  20. Drowsiness detection using heart rate variability.

    PubMed

    Vicente, José; Laguna, Pablo; Bartra, Ariadna; Bailón, Raquel

    2016-06-01

    It is estimated that 10-30 % of road fatalities are related to drowsy driving. Driver's drowsiness detection based on biological and vehicle signals is being studied in preventive car safety. Autonomous nervous system activity, which can be measured noninvasively from the heart rate variability (HRV) signal obtained from surface electrocardiogram, presents alterations during stress, extreme fatigue and drowsiness episodes. We hypothesized that these alterations manifest on HRV and thus could be used to detect driver's drowsiness. We analyzed three driving databases in which drivers presented different sleep-deprivation levels, and in which each driving minute was annotated as drowsy or awake. We developed two different drowsiness detectors based on HRV. While the drowsiness episodes detector assessed each minute of driving as "awake" or "drowsy" with seven HRV derived features (positive predictive value 0.96, sensitivity 0.59, specificity 0.98 on 3475 min of driving), the sleep-deprivation detector discerned if a driver was suitable for driving or not, at driving onset, as function of his sleep-deprivation state. Sleep-deprivation state was estimated from the first three minutes of driving using only one HRV feature (positive predictive value 0.80, sensitivity 0.62, specificity 0.88 on 30 drivers). Incorporating drowsiness assessment based on HRV signal may add significant improvements to existing car safety systems. PMID:26780463

  1. Heart Rate and Risk of Cancer Death in Healthy Men

    PubMed Central

    Jouven, Xavier; Escolano, Sylvie; Celermajer, David; Empana, Jean-Philippe; Bingham, Annie; Hermine, Olivier; Desnos, Michel; Perier, Marie-Cécile; Marijon, Eloi; Ducimetière, Pierre

    2011-01-01

    Background Data from several previous studies examining heart-rate and cardiovascular risk have hinted at a possible relationship between heart-rate and non-cardiac mortality. We thus systematically examined the predictive value of heart-rate variables on the subsequent risk of death from cancer. Methods In the Paris Prospective Study I, 6101 asymptomatic French working men aged 42 to 53 years, free of clinically detectable cardiovascular disease and cancer, underwent a standardized graded exercise test between 1967 and 1972. Resting heart-rate, heart-rate increase during exercise, and decrease during recovery were measured. Change in resting heart-rate over 5 years was also available in 5139 men. Mortality including 758 cancer deaths was assessed over the 25 years of follow-up. Findings There were strong, graded and significant relationships between all heart-rate parameters and subsequent cancer deaths. After adjustment for age and tobacco consumption and, compared with the lowest quartile, those with the highest quartile for resting heart-rate had a relative risk of 2.4 for cancer deaths (95% confidence interval: 1.9–2.9, p<0.0001) This was similar after adjustment for traditional cardiovascular risk factors and was observed for the commonest malignancies (respiratory and gastrointestinal). Similarly, significant relationships with cancer death were observed between poor heart rate increase during exercise, poor decrease during recovery and greater heart-rate increase over time (p<0.0001 for all). Interpretation Resting and exercise heart rate had consistent, graded and highly significant associations with subsequent cancer mortality in men. PMID:21826196

  2. Assessing Heart Rate in Physical Education. Assessment Series: K-12 Physical Education.

    ERIC Educational Resources Information Center

    Buck, Marilyn M.

    This guide discusses the assessment of heart rate and, in particular, the assessment of heart rate using a heart monitor. Part 1, "Foundation for the Use of Heart Rate," reviews literature about heart rate assessment and heart rate monitors, offering an overview of national guidelines for physical activity. It focuses on the importance of physical…

  3. Using Target Heart-Rate Zones in Your Class

    ERIC Educational Resources Information Center

    Gilbert, Jennie A.

    2005-01-01

    Should teachers teach the calculation of target heart rate to students? And when is it appropriate to engage students in the attainment of these heart rates during physical education class activities? The answers to these questions are not easy. One might be tempted to state a simple yes or no and to identify a specific age to begin using training…

  4. Effect of Age and Other Factors on Maximal Heart Rate.

    ERIC Educational Resources Information Center

    Londeree, Ben R.; Moeschberger, Melvin L.

    1982-01-01

    To reduce confusion regarding reported effects of age on maximal exercise heart rate, a comprehensive review of the relevant English literature was conducted. Data on maximal heart rate after exercising with a bicycle, a treadmill, and after swimming were analyzed with regard to physical fitness and to age, sex, and racial differences. (Authors/PP)

  5. Heart Rate Variability in Depressed Elderly

    PubMed Central

    Jindal, Ripu D.; Vasko, Raymond C.; Jennings, J. Richard; Fasiczka, Amy L.; Thase, Michael E.; Reynolds, Charles F.

    2009-01-01

    Objective The present study examines a measure of cardiac autonomic function, the heart rate variability (HRV), in a group of depressed elderly. Cardiac autonomic abnormalities have been implicated as a potential mediator of cardiovascular events and sudden death in depression. Because aging is associated with decreased cardiac vagal activity, it is possible that autonomic abnormalities are even more pronounced in the older depressed patients. Design Cross-sectional comparison between those with or without depression. The groups were compared using the Wilcoxon matched-pair sign-rank test. Setting Advanced Center for Interventions and Services Research for Late-Life Mood Disorders at University of Pittsburgh Medical Center. Participants Fifty-three patients with major depression (mean age: 73.3; SD: 7.4; range: 60–93) and an equal number of age and gender-matched subjects as a comparison group. Intervention None. Measurements Time domain and frequency domain measures of HRV. Results The groups did not differ in any of the time domain or frequency domain measures of HRV. As expected, subjects without depression displayed decreasing cardiac vagal function with aging (Spearman correlation coefficient rs = −0.33, p = 0.02). However, there was no significant change in vagal function with age in the depressed (r = 0.12, p = 0.38). Post-hoc analysis using Fisher’s zr transformation revealed that the relationship between age and cardiac vagal function was significantly different between the groups (z = 2.32, p = 0.02). Conclusions Our findings suggest that age has differential influence on vagal function in individuals with and without depression, a difference with implications for cardiovascular disease risk in depression. Prospective studies of cardiac vagal activity in depressed patients with or without preexisting cardiac disease in different age groups are needed to replicate and extend these findings. PMID:18978247

  6. Impact of basal heart rate on long-term prognosis of heart transplant patients.

    PubMed

    Melero-Ferrer, Josep L; Sánchez-Lázaro, Ignacio J; Almenar-Bonet, Luis; Martínez-Dolz, Luis; Buendía-Fuentes, Francisco; Portolés-Sanz, Manuel; Rivera-Otero, Miguel; Salvador-Sanz, Antonio

    2013-05-01

    Previous studies in patients with heart failure have shown that an elevated basal heart rate (HR) is associated with a poor outcome. Our aim with this study was to investigate if this relationship is also present in heart transplantation (HTx) recipients. From 2003 until 2010, 256 HTx performed in our center were recruited. Patients who required pacemaker, heart-lung transplants, pediatrics, retransplants, and those patients with a survival of less than 1 year were excluded. The final number included in the analysis was 191. Using the HR obtained by EKG during elective admission at 1 year post-HTx and the survival rate, an ROC-curve was performed. The best point under the curve was achieved with 101 beats per minute (bpm), so patients were divided in two groups according to their HR. A comparison between survival curves of both groups was performed (Kaplan-Meier). Subsequently, a multivariate analysis considering HR and other variables with influence on survival according to the literature was carried out. A total of 136 patients were included in the group with HR ≤100 bpm, and 55 in the one with HR >100 bpm. There were no basal differences in both groups except for primary graft failure, which was more frequent in the >100 bpm group (30.9 vs. 17%, P = 0.033). Patients with ≤100 bpm had a better long prognosis (P < 0.001). The multivariate analysis proved that high HR was an independent predictor of mortality. Our study shows that HR should be considered as a prognosis factor in HTx patients. PMID:23489468

  7. Effects of Vibration and G-Loading on Heart Rate, Breathing Rate, and Response Time

    NASA Technical Reports Server (NTRS)

    Godinez, Angelica; Ayzenberg, Ruthie; Liston, Dorian B.; Stone, Leland S.

    2013-01-01

    Aerospace and applied environments commonly expose pilots and astronauts to G-loading and vibration, alone and in combination, with well-known sensorimotor (Cohen, 1970) and performance consequences (Adelstein et al., 2008). Physiological variables such as heart rate (HR) and breathing rate (BR) have been shown to increase with G-loading (Yajima et al., 1994) and vibration (e.g. Guignard, 1965, 1985) alone. To examine the effects of G-loading and vibration, alone and in combination, we measured heart rate and breathing rate under aerospace-relevant conditions (G-loads of 1 Gx and 3.8 Gx; vibration of 0.5 gx at 8, 12, and 16 Hz).

  8. Interpretation of the electronic fetal heart rate during labor.

    PubMed

    Sweha, A; Hacker, T W; Nuovo, J

    1999-05-01

    Electronic fetal heart rate monitoring is commonly used to assess fetal well-being during labor. Although detection of fetal compromise is one benefit of fetal monitoring, there are also risks, including false-positive tests that may result in unnecessary surgical intervention. Since variable and inconsistent interpretation of fetal heart rate tracings may affect management, a systematic approach to interpreting the patterns is important. The fetal heart rate undergoes constant and minute adjustments in response to the fetal environment and stimuli. Fetal heart rate patterns are classified as reassuring, nonreassuring or ominous. Nonreassuring patterns such as fetal tachycardia, bradycardia and late decelerations with good short-term variability require intervention to rule out fetal acidosis. Ominous patterns require emergency intrauterine fetal resuscitation and immediate delivery. Differentiating between a reassuring and nonreassuring fetal heart rate pattern is the essence of accurate interpretation, which is essential to guide appropriate triage decisions. PMID:10323356

  9. Learning by Heart: Students Use Heart Rate Patterns To Identify Nervous System Imbalances.

    ERIC Educational Resources Information Center

    Ackerly, Spafford C.

    2001-01-01

    Introduces a science unit on heart rate variability (HVR) patterns. Uses spectral analysis to determine the effects of environmental stimulants such as music and emotional stress on heart rate. Observes relaxation techniques and their effects on the autonomous nervous system. (Contains 12 references.) (YDS)

  10. Heart Rate Dependency of Large Artery Stiffness.

    PubMed

    Tan, Isabella; Spronck, Bart; Kiat, Hosen; Barin, Edward; Reesink, Koen D; Delhaas, Tammo; Avolio, Alberto P; Butlin, Mark

    2016-07-01

    Carotid-femoral pulse wave velocity (cfPWV) quantifies large artery stiffness, it is used in hemodynamic research and is considered a useful cardiovascular clinical marker. cfPWV is blood pressure (BP) dependent. Intrinsic heart rate (HR) dependency of cfPWV is unknown because increasing HR is commonly accompanied by increasing BP. This study aims to quantify cfPWV dependency on acute, sympathovagal-independent changes in HR, independent of BP. Individuals (n=52, age 40-93 years, 11 female) with in situ cardiac pacemakers or cardioverter defibrillators were paced at 60, 70, 80, 90, and 100 bpm. BP and cfPWV were measured at each HR. Both cfPWV (mean [95% CI], 0.31 [0.26-0.37] m/s per 10 bpm; P<0.001) and central aortic diastolic pressure (3.78 [3.40-4.17] mm Hg/10 bpm; P<0.001) increased with HR. The HR effect on cfPWV was isolated by correcting the BP effects by 3 different methods: (1) statistically, by a linear mixed model; (2) mathematically, using an exponential relationship between BP and cross-sectional lumen area; and (3) using measured BP dependency of cfPWV derived from changes in BP induced by orthostatic changes (seated and supine) in a subset of subjects (n=17). The BP-independent effects of HR on cfPWV were quantified as 0.20 [0.11-0.28] m/s per 10 bpm (P<0.001, method 1), 0.16 [0.11-0.22] m/s per 10 bpm (P<0.001, method 2), and 0.16 [0.11-0.21] m/s per 10 bpm (P<0.001, method 3). With a mean HR dependency in the range of 0.16 to 0.20 m/s per 10 bpm, cfPWV may be considered to have minimal physiologically relevant changes for small changes in HR, but larger differences in HR must be considered as contributing to significant differences in cfPWV. PMID:27245180

  11. Effect of suprachiasmatic lesions on diurnal heart rate rhythm in the rat

    NASA Technical Reports Server (NTRS)

    Saleh, M. A.; Winget, C. M.

    1977-01-01

    Heart rate and locomotor activity of rats kept under 12L/12D illumination regimen were recorded every six minutes for ten days using implantable radio transmitters. Some of the rats then received bilateral RF lesions into the suprachiasmatic nucleus (SCN). Control sham operations were performed on the rest of the animals. After recovery from surgery, recording of heart rate and locomotor activity was continued for ten days. SCN-lesioned rats showed no significant diurnal fluctuation in heart rate, while normal and sham-operated rats showed the normal diurnal rhythm in that function. The arrhythmic diurnal heart-rate pattern of SCN rats appeared to be correlated with their sporadic activity pattern. The integrity of the suprachiasmatic nucleus is therefore necessary for the generation and/or expression of diurnal rhythmicity in heart rate in the rat.

  12. Visual discrimination learning in dwarf goats and associated changes in heart rate and heart rate variability.

    PubMed

    Langbein, Jan; Nürnberg, G; Manteuffel, G

    2004-09-30

    We studied visual discrimination learning in a group of Nigerian dwarf goats using a computer-based learning device which was integrated in the animals' home pen. We conducted three consecutive learning tasks (T1, T2 and T3), each of which lasted for 13 days. In each task, a different set of four visual stimuli was presented on a computer screen in a four-choice design. Predefined sequences of stimulus combinations were presented in a pseudorandom order. Animals were rewarded with drinking water when they chose the positive stimulus by pressing a button next to it. Noninvasive measurements of goats' heartbeat intervals were carried out on the first and the last 2 days of each learning task. We analysed heart rate (HR) and heart rate variability (HRV) of resting animals to study sustained physiological effects related to general learning challenge rather than acute excitement during an actual learning session. The number of trials to reach the learning criterion was 1000 in T1, when visual stimuli were presented to the goats for the first time, but decreased to 210 in T2 and 240 in T3, respectively. A stable plateau of correct choices between 70% and 80% was reached on Day 10 in T1, on Day 8 in T2 and on Day 6 in T3. We found a significant influence of the task and of the interaction between task and day on learning success. Whereas HR increased throughout T1, this relationship was inverted in T2 and T3, indicating different effects on the HR depending on how familiar goats were with the learning task. We found a significant influence of the task and the interaction between task and time within the task on HRV parameters, indicating changes of vagal activity at the heart. The results suggest that changes in HR related to learning were predominantly caused by a withdrawal of vagal activity at the heart. With regard to nonlinear processes in heartbeat regulation, increased deterministic shares of HRV indicated that the animals did not really relax until the end of T3

  13. Prosthetic heart valves: Objective Performance Criteria versus randomized clinical trial.

    PubMed

    Grunkemeier, Gary L; Jin, Ruyun; Starr, Albert

    2006-09-01

    The current Food and Drug Administration (FDA) heart valve guidance document uses an objective performance criteria (OPC) methodology to evaluate the clinical performance of prosthetic heart valves. OPC are essentially historical controls, but they have turned out to be an adequate, and perhaps optimal, study design in this situation. Heart valves have a simple open-and-close mechanism, device effectiveness is easy to document, and the common complications (thromboembolism, thrombosis, bleeding, leak, and infection) are well known and easily detected. Thus, randomized clinical trials (RCTs) have not been deemed necessary for the regulatory approval of prosthetic heart valves. The OPC are derived from the average complication rates of all approved heart valves. Studies based on OPC have been shown to work well; many different valve models have gained FDA market approval based on this methodology. Although heart valve RCTs are not required by the FDA, they have been done to compare valves or treatment regimens after approval. Recently, the Artificial Valve Endocarditis Reduction Trial (AVERT) was designed to compare a new Silzone sewing ring, designed to reduce infection, with the Standard sewing ring on a St. Jude Medical heart valve. This was the largest heart valve RCT ever proposed (4,400 valve patients, followed for as long as 4 years), but it was stopped prematurely because of a high leak rate associated with the Silzone valve. Examining the results showed that a much smaller, OPC-based study with 800 patient-years would have been sufficient to disclose this complication of the Silzone valve. PMID:16928482

  14. Optimized Treatment and Heart Rate Reduction in Chronic Heart Failure

    PubMed Central

    Moreno, Irineu Blanco; Del Carlo, Carlos Henrique; Pereira-Barretto, Antônio Carlos

    2013-01-01

    Background Heart failure (HF) is a syndrome that leads to poor outcome in advanced forms. The neurohormonal blockade modifies this natural history; however, it is often suboptimal. Objective The aim of this study is to assess at what percentage cardiologists used to treating HF can prescribe target doses of drugs of proven efficacy. Methods A total of 104 outpatients with systolic dysfunction were consecutively enrolled, all under stabilized treatment. Demographic and treatment data were evaluated and the doses achieved were verified. The findings are shown as percentages and correlations are made between different variables. Results The mean age of patients was 64.1 ± 14.2 years, with SBP =115.4 ± 15.3, HR = 67.8 ± 9.4 bpm, weight = 76.0 ± 17.0 kg and sinus rhythm (90.4%). As for treatment, 93.3% received a RAS blocker (ACEI 52.9%), all received beta-blockers (BB), the most often prescribed being carvedilol (92.3%). As for the doses: 97.1% of those receiving an ARB were below the optimal dose and of those who received ACEI, 52.7% received an optimized dose. As for the BB, target doses were prescribed to 76.0% of them. In this group of patients, most with BB target dose, it can be seen that 36.5% had HR ≥ 70 bpm in sinus rhythm. Conclusion Cardiologists used to treating HF can prescribe target doses of ACEI and BB to most patients. Even though they receive the recommended doses, about one third of patients persists with HR > 70 bpm and should have their treatment optimized. PMID:24100693

  15. Stochastic heart-rate model can reveal pathologic cardiac dynamics

    NASA Astrophysics Data System (ADS)

    Kuusela, Tom

    2004-03-01

    A simple one-dimensional Langevin-type stochastic difference equation can simulate the heart-rate fluctuations in a time scale from minutes to hours. The model consists of a deterministic nonlinear part and a stochastic part typical of Gaussian noise, and both parts can be directly determined from measured heart-rate data. Data from healthy subjects typically exhibit the deterministic part with two or more stable fixed points. Studies of 15 congestive heart-failure subjects reveal that the deterministic part of pathologic heart dynamics has no clear stable fixed points. Direct simulations of the stochastic model for normal and pathologic cases can produce statistical parameters similar to those of real subjects. Results directly indicate that pathologic situations simplify the heart-rate control system.

  16. Phase Transition in a Healthy Human Heart Rate

    NASA Astrophysics Data System (ADS)

    Kiyono, Ken; Struzik, Zbigniew R.; Aoyagi, Naoko; Togo, Fumiharu; Yamamoto, Yoshiharu

    2005-07-01

    A healthy human heart rate displays complex fluctuations which share characteristics of physical systems in a critical state. We demonstrate that the human heart rate in healthy individuals undergoes a dramatic breakdown of criticality characteristics, reminiscent of continuous second order phase transitions. By studying the germane determinants, we show that the hallmark of criticality—highly correlated fluctuations—is observed only during usual daily activity, and a breakdown of these characteristics occurs in prolonged, strenuous exercise and sleep. This finding is the first reported discovery of the dynamical phase transition phenomenon in a biological control system and will be a key to understanding the heart rate control system in health and disease.

  17. Heart Rate Turbulence as Risk-Predictor after Myocardial Infarction

    PubMed Central

    Zuern, Christine S.; Barthel, Petra; Bauer, Axel

    2011-01-01

    Heart rate turbulence (HRT) is the baroreflex-mediated short-term oscillation of cardiac cycle lengths after spontaneous ventricular premature complexes. HRT is composed of a brief heart rate acceleration followed by a gradual heart rate deceleration. In high risk patients after myocardial infarction (MI) HRT is blunted or diminished. Since its first description in 1999 HRT emerged as one of the most potent risk factors after MI. Predictive power of HRT has been studied in more than 10,000 post-infarction patients. This review is intended to provide an overview of HRT as risk-predictor after MI. PMID:22180744

  18. Fetal heart rate monitoring: from Doppler to computerized analysis.

    PubMed

    Kwon, Ji Young; Park, In Yang

    2016-03-01

    The monitoring of fetal heart rate (FHR) status is an important method to check well-being of the baby during labor. Since the electronic FHR monitoring was introduced 40 years ago, it has been expected to be an innovative screening test to detect fetuses who are becoming hypoxic and who may benefit from cesarean delivery or operative vaginal delivery. However, several randomized controlled trials have failed to prove that electronic FHR monitoring had any benefit of reducing the perinatal mortality and morbidity. Also it is now clear that the FHR monitoring had high intra- and interobserver disagreements and increased the rate of cesarean delivery. Despite such limitations, the FHR monitoring is still one of the most important obstetric procedures in clinical practice, and the cardiotocogram is the most-used equipment. To supplement cardiotocogram, new methods of computerized FHR analysis and electrocardiogram have been developed, and several clinical researches have been currently performed. Computerized equipment makes us to analyze beat-to-beat variability and short term heart rate patterns. Furthermore, researches about multiparameters of FHR variability will be ongoing. PMID:27004196

  19. Fetal heart rate monitoring: from Doppler to computerized analysis

    PubMed Central

    Kwon, Ji Young

    2016-01-01

    The monitoring of fetal heart rate (FHR) status is an important method to check well-being of the baby during labor. Since the electronic FHR monitoring was introduced 40 years ago, it has been expected to be an innovative screening test to detect fetuses who are becoming hypoxic and who may benefit from cesarean delivery or operative vaginal delivery. However, several randomized controlled trials have failed to prove that electronic FHR monitoring had any benefit of reducing the perinatal mortality and morbidity. Also it is now clear that the FHR monitoring had high intra- and interobserver disagreements and increased the rate of cesarean delivery. Despite such limitations, the FHR monitoring is still one of the most important obstetric procedures in clinical practice, and the cardiotocogram is the most-used equipment. To supplement cardiotocogram, new methods of computerized FHR analysis and electrocardiogram have been developed, and several clinical researches have been currently performed. Computerized equipment makes us to analyze beat-to-beat variability and short term heart rate patterns. Furthermore, researches about multiparameters of FHR variability will be ongoing. PMID:27004196

  20. Heart Rate at Hospital Discharge in Patients With Heart Failure Is Associated With Mortality and Rehospitalization

    PubMed Central

    Laskey, Warren K.; Alomari, Ihab; Cox, Margueritte; Schulte, Phillip J.; Zhao, Xin; Hernandez, Adrian F.; Heidenreich, Paul A.; Eapen, Zubin J.; Yancy, Clyde; Bhatt, Deepak L.; Fonarow, Gregg C.

    2015-01-01

    Background Whether heart rate upon discharge following hospitalization for heart failure is associated with long‐term adverse outcomes and whether this association differs between patients with sinus rhythm (SR) and atrial fibrillation (AF) have not been well studied. Methods and Results We conducted a retrospective cohort study from clinical registry data linked to Medicare claims for 46 217 patients participating in Get With The Guidelines®–Heart Failure. Cox proportional‐hazards models were used to estimate the association between discharge heart rate and all‐cause mortality, all‐cause readmission, and the composite outcome of mortality/readmission through 1 year. For SR and AF patients with heart rate ≥75, the association between heart rate and mortality (expressed as hazard ratio [HR] per 10 beats‐per‐minute increment) was significant at 0 to 30 days (SR: HR 1.30, 95% CI 1.22 to 1.39; AF: HR 1.23, 95% CI 1.16 to 1.29) and 31 to 365 days (SR: HR 1.15, 95% CI 1.12 to 1.20; AF: HR 1.05, 95% CI 1.01 to 1.08). Similar associations between heart rate and all‐cause readmission and the composite outcome were obtained for SR and AF patients from 0 to 30 days but only in the composite outcome for SR patients over the longer term. The HR from 0 to 30 days exceeded that from 31 to 365 days for both SR and AF patients. At heart rates <75, an association was significant for mortality only for both SR and AF patients. Conclusions Among older patients hospitalized with heart failure, higher discharge heart rate was associated with increased risks of death and rehospitalization, with higher risk in the first 30 days and for SR compared with AF. PMID:25904590

  1. Dominant Parasympathetic Modulation of Heart Rate and Heart Rate Variability in a Wild-Caught Seabird.

    PubMed

    Carravieri, Alice; Müller, Martina S; Yoda, Ken; Hayama, Shin-Ichi; Yamamoto, Maki

    2016-01-01

    Heart rate (HR) and heart rate variability (HRV) provide noninvasive measures of the relative activity of the parasympathetic nervous system (PNS), which promotes self-maintenance and restoration, and the sympathetic nervous system (SNS), which prepares an animal for danger. The PNS decreases HR, whereas the SNS increases HR. The PNS and SNS also contribute to oscillations in heartbeat intervals at different frequencies, producing HRV. HRV promotes resilience and adjustment capacity in the organism to intrinsic and extrinsic changes. Measuring HRV can reveal the condition and emotional state of animals, including aspects of their stress physiology. Until now, the functioning of the PNS and SNS and their relationship with other physiological systems have been studied almost exclusively in humans. In this study, we tested their influence on HR and HRV for the first time in a wild-caught seabird, the streaked shearwater (Calonectris leucomelas). We analyzed electrocardiograms collected from birds carrying externally attached HR loggers and that received injections that pharmacologically blocked the PNS, the SNS, or both, as well as those that received a saline (sham) injection or no injection (control). The PNS strongly dominated modulation of HR and also HRV across all frequencies, whereas the SNS contributed only slightly to low-frequency oscillations. The saline injection itself acted as a stressor, causing a dramatic drop in PNS activity in HRV and an increase in HR, though PNS activity continued to dominate even during acute stress. Dominant PNS activity is expected for long-lived species, which should employ physiological strategies that minimize somatic deterioration coming from stress. PMID:27327178

  2. Signal processing methodologies for an acoustic fetal heart rate monitor

    NASA Technical Reports Server (NTRS)

    Pretlow, Robert A., III; Stoughton, John W.

    1992-01-01

    Research and development is presented of real time signal processing methodologies for the detection of fetal heart tones within a noise-contaminated signal from a passive acoustic sensor. A linear predictor algorithm is utilized for detection of the heart tone event and additional processing derives heart rate. The linear predictor is adaptively 'trained' in a least mean square error sense on generic fetal heart tones recorded from patients. A real time monitor system is described which outputs to a strip chart recorder for plotting the time history of the fetal heart rate. The system is validated in the context of the fetal nonstress test. Comparisons are made with ultrasonic nonstress tests on a series of patients. Comparative data provides favorable indications of the feasibility of the acoustic monitor for clinical use.

  3. Method of Discriminant Gravity Tolerance using Heart Rate Variability

    NASA Astrophysics Data System (ADS)

    Yoshida, Yutaka; Yokoyama, Kiyoko; Takada, Hiroki; Iwase, Satoshi

    When returning on the earth by the space flight, the space deconditioning may be developed. As this countermeasure, the artificial gravity load device using the centrifuge is proposed in the space station. But the gravity load might cause the faint, and safe gravity load is uncertainty. We proposed that discriminate strength of gravity tolerance using heart rate variability time series. Step function was inputted to AR model estimated from heart rate variability time series during rest or under light gravity load, and strength of the gravity tolerance was discriminated by the step response function. On the result, discriminant accuracy was 87.5% by using heart rate variability time series when gravity load of 1.0 G was added to the human lying on the supine. Therefore, possibility of discriminant of gravity tolerance was obtained by using heart rate variability time series when sympathetic hyperactivity. Discriminant of the gravity tolerance is expected before countermeasure of space deconditioning is executed.

  4. Heart Rate Response and Lactic Acid Concentration in Squash Players.

    ERIC Educational Resources Information Center

    Beaudin, Paula; And Others

    1978-01-01

    It was concluded that playing squash is an activity that results in heart rate responses of sufficient intensity to elicit aerobic training effects without producing high lactic acid concentration in the blood. (MM)

  5. Heart rate and estimated energy expenditure during ballroom dancing.

    PubMed Central

    Blanksby, B A; Reidy, P W

    1988-01-01

    Ten competitive ballroom dance couples performed simulated competitive sequences of Modern and Latin American dance. Heart rate was telemetered during the dance sequences and related to direct measures of oxygen uptake and heart rate obtained while walking on a treadmill. Linear regression was employed to estimate gross and net energy expenditures of the dance sequences. A multivariate analysis of variance with repeated measures on the dance factor was applied to the data to test for interaction and main effects on the sex and dance factors. Overall mean heart rate values for the Modern dance sequence were 170 beats.min-1 and 173 beats.min-1 for males and females respectively. During the Latin American sequence mean overall heart rate for males was 168 beats.min-1 and 177 beats.min-1 for females. Predicted mean gross values of oxygen consumption for the males were 42.8 +/- 5.7 ml.kg-1 min-1 and 42.8 +/- 6.9 ml.kg-1 min-1 for the Modern and Latin American sequences respectively. Corresponding gross estimates of oxygen consumption for the females were 34.7 +/- 3.8 ml.kg-1 min-1 and 36.1 +/- 4.1 ml.kg-1 min-1. Males were estimated to expand 54.1 +/- 8.1 kJ.min-1 of energy during the Modern sequence and 54.0 +/- 9.6 kJ.min-1 during the Latin American sequence, while predicted energy expenditure for females was 34.7 +/- 3.8 kJ.min-1 and 36.1 +/- 4.1 kJ.min-1 for Modern and Latin American dance respectively. The results suggested that both males and females were dancing at greater than 80% of their maximum oxygen consumption. A significant difference between males and females was observed for predicted gross and net values of oxygen consumption (in L.min-1 and ml.kg-1 min-1). PMID:3167503

  6. Heart rate and estimated energy expenditure during ballroom dancing.

    PubMed

    Blanksby, B A; Reidy, P W

    1988-06-01

    Ten competitive ballroom dance couples performed simulated competitive sequences of Modern and Latin American dance. Heart rate was telemetered during the dance sequences and related to direct measures of oxygen uptake and heart rate obtained while walking on a treadmill. Linear regression was employed to estimate gross and net energy expenditures of the dance sequences. A multivariate analysis of variance with repeated measures on the dance factor was applied to the data to test for interaction and main effects on the sex and dance factors. Overall mean heart rate values for the Modern dance sequence were 170 beats.min-1 and 173 beats.min-1 for males and females respectively. During the Latin American sequence mean overall heart rate for males was 168 beats.min-1 and 177 beats.min-1 for females. Predicted mean gross values of oxygen consumption for the males were 42.8 +/- 5.7 ml.kg-1 min-1 and 42.8 +/- 6.9 ml.kg-1 min-1 for the Modern and Latin American sequences respectively. Corresponding gross estimates of oxygen consumption for the females were 34.7 +/- 3.8 ml.kg-1 min-1 and 36.1 +/- 4.1 ml.kg-1 min-1. Males were estimated to expand 54.1 +/- 8.1 kJ.min-1 of energy during the Modern sequence and 54.0 +/- 9.6 kJ.min-1 during the Latin American sequence, while predicted energy expenditure for females was 34.7 +/- 3.8 kJ.min-1 and 36.1 +/- 4.1 kJ.min-1 for Modern and Latin American dance respectively. The results suggested that both males and females were dancing at greater than 80% of their maximum oxygen consumption. A significant difference between males and females was observed for predicted gross and net values of oxygen consumption (in L.min-1 and ml.kg-1 min-1). PMID:3167503

  7. Discrimination power of long-term heart rate variability measures for chronic heart failure detection.

    PubMed

    Melillo, Paolo; Fusco, Roberta; Sansone, Mario; Bracale, Marcello; Pecchia, Leandro

    2011-01-01

    The aim of this study was to investigate the discrimination power of standard long-term heart rate variability (HRV) measures for the diagnosis of chronic heart failure (CHF). The authors performed a retrospective analysis on four public Holter databases, analyzing the data of 72 normal subjects and 44 patients suffering from CHF. To assess the discrimination power of HRV measures, an exhaustive search of all possible combinations of HRV measures was adopted and classifiers based on Classification and Regression Tree (CART) method was developed, which is a non-parametric statistical technique. It was found that the best combination of features is: Total spectral power of all NN intervals up to 0.4 Hz (TOTPWR), square root of the mean of the sum of the squares of differences between adjacent NN intervals (RMSSD) and standard deviation of the averages of NN intervals in all 5-min segments of a 24-h recording (SDANN). The classifiers based on this combination achieved a specificity rate and a sensitivity rate of 100.00 and 89.74%, respectively. The results are comparable with other similar studies, but the method used is particularly valuable because it provides an easy to understand description of classification procedures, in terms of intelligible "if … then …" rules. Finally, the rules obtained by CART are consistent with previous clinical studies. PMID:21203855

  8. Assessment of anxiety using heart rate nonlinear dynamics

    NASA Astrophysics Data System (ADS)

    Thayer, Julian F.; Friedman, Bruce H.

    1993-11-01

    Various anxiety states have been linked with disorders of the autonomic nervous system. These autonomic disorders may be revealed by analysis of physiological time series such as the heart rate interbeat interval series. The present paper reports a general model of biological system functioning and related assessment indices based on recent nonlinear dynamical systems approaches. In particular, two experimental studies are reported which suggest the utility of heart rate nonlinear dynamics in the assessment of anxiety.

  9. Heart rate variability in natural time and 1/f "noise"

    NASA Astrophysics Data System (ADS)

    Sarlis, N. V.; Skordas, E. S.; Varotsos, P. A.

    2009-07-01

    Several studies have shown that heart rate fluctuations exhibit the ubiquitous 1/f behavior which is altered in desease. Furthermore, the analysis of electrocardiograms in natural time reveals that important malfunctions in the complex system of the human heart can be identified. Here, we present a simple evolution model in natural time that exhibits the 1/fa behavior with a close to unity. The results of this model are consistent with a progressive modification of heart rate variability in healthy children and adolescents. The model results in complexity measures that separate healthy dynamics from patients as well as from sudden cardiac death individuals.

  10. Human heart rate variability relation is unchanged during motion sickness

    NASA Technical Reports Server (NTRS)

    Mullen, T. J.; Berger, R. D.; Oman, C. M.; Cohen, R. J.

    1998-01-01

    In a study of 18 human subjects, we applied a new technique, estimation of the transfer function between instantaneous lung volume (ILV) and instantaneous heart rate (HR), to assess autonomic activity during motion sickness. Two control recordings of ILV and electrocardiogram (ECG) were made prior to the development of motion sickness. During the first, subjects were seated motionless, and during the second they were seated rotating sinusoidally about an earth vertical axis. Subjects then wore prism goggles that reverse the left-right visual field and performed manual tasks until they developed moderate motion sickness. Finally, ILV and ECG were recorded while subjects maintained a relatively constant level of sickness by intermittent eye closure during rotation with the goggles. Based on analyses of ILV to HR transfer functions from the three conditions, we were unable to demonstrate a change in autonomic control of heart rate due to rotation alone or due to motion sickness. These findings do not support the notion that moderate motion sickness is manifested as a generalized autonomic response.

  11. Abnormal intermittency of heart rate in patients with neurocardiogenic syncope

    NASA Astrophysics Data System (ADS)

    Yum, Myung-Kul; Kim, Kyung-Sik; Kim, June-Soo

    2002-03-01

    Introduction: We aim to test our hypothesis that, during daily activity, though not as prominent as during HUT test, the patients may show different degree of intermittency in heart rates compared to healthy persons. METHOD AND RESULTS: Thirty patients with neurocardiogenic syncope who showed a positive HUT test and thirty healthy controls without history of syncope were included. Their twenty-four hour ambulatory electrocardiograms were digitized and RR interval (RRI) data of six-hour interval were analyzed. To quantify the intermittency (C1) behavior, The intermittency analysis was performed using Mexican hat wavelet. For the syncope group, the values of C1 were significantly higher at 6AM-6PM and lower at 6AM-midnight, respectively. However, the values were not different at midnight-6AM. The significant night-day circadian change shown in the control group was lost in C1. CONCLUSION: When compared to healthy control, the patients with neurocardiogenic syncope shows increased intermittency of heart rates in daytime during daily activity, and abnormal circadian rhythms of the index. These new findings may be useful for investigating the pathophysiology of neurocardiogenic syncope and early identification of the patients.

  12. Transcontinental and translational high-tech acupuncture research using computer-based heart rate and "Fire of Life" heart rate variability analysis.

    PubMed

    Litscher, Gerhard

    2010-09-01

    A variable heartbeat was considered a sign of good health by ancient Asian physicians. Today, new computer-based methods (e.g., "Fire of Life" analysis) allow quantification of heart rate and heart rate variability during acupuncture. The objective of this article is to compare different acupuncture methods to evaluate the influence of acupuncture on heart rhythm in short-term and long-term measurements. There were four main sections in this study: (A) a randomized controlled study using needle acupuncture and acupressure at Yintang (Ex1); (B) an innovative blue (violet) laser acupuncture randomized controlled study in Asian volunteers; (C) a comparative study using moxibustion methods; and (D) teleacupuncture. A total of 72 patients (mean age ± SD: 27.9 ± 8.6 years) were monitored over periods of 20 minutes to 24 hours in Asia and Austria. Acupuncture was performed with metal needles (in sections A, C and D) or blue laser (in section B) on Yintang, Neiguan, Guanyuan or a special acupuncture regimen for stress disorders (in sections A, B, C and D, respectively). Significant decreases in heart rate after verum intervention at Yintang, Neiguan and Guanyuan were found. Improvements in state of health following teleacupuncture were also noted. Computer-based heart rate and heart rate variability analysis was demonstrated to be effective in evaluating the status of health during acupuncture. PMID:20869016

  13. 1/f scaling in heart rate requires antagonistic autonomic control

    NASA Astrophysics Data System (ADS)

    Struzik, Zbigniew R.; Hayano, Junichiro; Sakata, Seiichiro; Kwak, Shin; Yamamoto, Yoshiharu

    2004-11-01

    We present systematic evidence for the origins of 1/f -type temporal scaling in human heart rate. The heart rate is regulated by the activity of two branches of the autonomic nervous system: the parasympathetic (PNS) and the sympathetic (SNS) nervous systems. We examine alterations in the scaling property when the balance between PNS and SNS activity is modified, and find that the relative PNS suppression by congestive heart failure results in a substantial increase in the Hurst exponent H towards random-walk scaling 1/f2 and a similar breakdown is observed with relative SNS suppression by primary autonomic failure. These results suggest that 1/f scaling in heart rate requires the intricate balance between the antagonistic activity of PNS and SNS.

  14. Effect of energy drink dose on exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise

    PubMed Central

    An, Sang Min; Park, Jong Suk; Kim, Sang Ho

    2014-01-01

    [Purpose] The purpose of this research was to investigate the effects of exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise on caffeine concentration of energy drink. [Methods] The volunteers for this study were 15 male university student. 15 subjects were taken basic physical examinations such as height, weight and BMI before the experiment. Primary tests were examined of VO2max per weight of each subjects by graded exercise test using Bruce protocol. Each of five subject was divided 3 groups (CON, ECGⅠ, ECGⅡ) by matched method based on weight and VO2max per weight what gained of primary test for minimize the differences of exercise capacity and ingestion of each groups. For the secondary tests, the groups of subjects were taken their materials before and after exercise as a blind test. After the ingestion, subjects were experimented on exercise test of VO2max 80% by treadmill until the all-out. Heart rate was measured by 1minute interval, and respiratory variables were analyzed VO2, VE, VT, RR and so on by automatic respiratory analyzer. And exercise exhaustion time was determined by stopwatch. Moreover, HRV was measured after exercise and recovery 3 min. [Results] Among the intake groups, ECGⅡ was showed the longest of exercise exhaustion time more than CON group (p = .05). Result of heart rate during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). Result of RPE during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). [Conclusion] In conclusion, EDGⅡ showed the significant increase of exercise exhaustion time more than CON group (p=.05) and not significant differences in HR, RPE, RER, HRV, HRR, blood pressure (p > .05). Therefore, 2.5 mg/kg-1 ingestion

  15. Gender- and age-related differences in heart rate dynamics: are women more complex than men?

    NASA Technical Reports Server (NTRS)

    Ryan, S. M.; Goldberger, A. L.; Pincus, S. M.; Mietus, J.; Lipsitz, L. A.

    1994-01-01

    OBJECTIVES. This study aimed to quantify the complex dynamics of beat-to-beat sinus rhythm heart rate fluctuations and to determine their differences as a function of gender and age. BACKGROUND. Recently, measures of heart rate variability and the nonlinear "complexity" of heart rate dynamics have been used as indicators of cardiovascular health. Because women have lower cardiovascular risk and greater longevity than men, we postulated that there are important gender-related differences in beat-to-beat heart rate dynamics. METHODS. We analyzed heart rate dynamics during 8-min segments of continuous electrocardiographic recording in healthy young (20 to 39 years old), middle-aged (40 to 64 years old) and elderly (65 to 90 years old) men (n = 40) and women (n = 27) while they performed spontaneous and metronomic (15 breaths/min) breathing. Relatively high (0.15 to 0.40 Hz) and low (0.01 to 0.15 Hz) frequency components of heart rate variability were computed using spectral analysis. The overall "complexity" of each heart rate time series was quantified by its approximate entropy, a measure of regularity derived from nonlinear dynamics ("chaos" theory). RESULTS. Mean heart rate did not differ between the age groups or genders. High frequency heart rate power and the high/low frequency power ratio decreased with age in both men and women (p < 0.05). The high/low frequency power ratio during spontaneous and metronomic breathing was greater in women than men (p < 0.05). Heart rate approximate entropy decreased with age and was higher in women than men (p < 0.05). CONCLUSIONS. High frequency heart rate spectral power (associated with parasympathetic activity) and the overall complexity of heart rate dynamics are higher in women than men. These complementary findings indicate the need to account for gender-as well as age-related differences in heart rate dynamics. Whether these gender differences are related to lower cardiovascular disease risk and greater longevity in

  16. Validity of a heart rate monitor during work in the laboratory and on the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Moore, A. D. Jr; Lee, S. M.; Greenisen, M. C.; Bishop, P.

    1997-01-01

    Accurate heart rate measurement during work is required for many industrial hygiene and ergonomics situations. The purpose of this investigation was to determine the validity of heart rate measurements obtained by a simple, lightweight, commercially available wrist-worn heart rate monitor (HRM) during work (cycle exercise) sessions conducted in the laboratory and also during the particularly challenging work environment of space flight. Three different comparisons were made. The first compared HRM data to simultaneous electrocardiogram (ECG) recordings of varying heart rates that were generated by an ECG simulator. The second compared HRM data to ECG recordings collected during work sessions of 14 subjects in the laboratory. Finally, ECG downlink and HRM data were compared in four astronauts who performed cycle exercise during space flight. The data were analyzed using regression techniques. The results were that the HRM recorded virtually identical heart rates compared with ECG recordings for the data set generated by an ECG simulator. The regression equation for the relationship between ECG versus HRM heart rate data during work in the laboratory was: ECG HR = 0.99 x (HRM) + 0.82 (r2 = 0.99). Finally, the agreement between ECG downlink data and HRM data during space flight was also very high, with the regression equation being: Downlink ECG HR = 1.05 x (HRM) -5.71 (r2 = 0.99). The results of this study indicate that the HRM provides accurate data and may be used to reliably obtain valid data regarding heart rate responses during work.

  17. Nonlinear systems dynamics in cardiovascular physiology: The heart rate delay map and lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Hooker, John C.

    1990-01-01

    A preliminary study of the applicability of nonlinear dynamic systems analysis techniques to low body negative pressure (LBNP) studies. In particular, the applicability of the heart rate delay map is investigated. It is suggested that the heart rate delay map has potential as a supplemental tool in the assessment of subject performance in LBNP tests and possibly in the determination of susceptibility to cardiovascular deconditioning with spaceflight.

  18. Assessing positive emotional states in dogs using heart rate and heart rate variability.

    PubMed

    Zupan, Manja; Buskas, Julia; Altimiras, Jordi; Keeling, Linda J

    2016-03-01

    Since most animal species have been recognized as sentient beings, emotional state may be a good indicator of welfare in animals. The goal of this study was to manipulate the environment of nine beagle research dogs to highlight physiological responses indicative of different emotional experiences. Stimuli were selected to be a more or a less positive food (meatball or food pellet) or social reward (familiar person or less familiar person). That all the stimuli were positive and of different reward value was confirmed in a runway motivation test. Dogs were tested individually while standing facing a display theatre where the different stimuli could be shown by lifting a shutter. The dogs approached and remained voluntarily in the test system. They were tested in four sessions (of 20s each) for each of the four stimuli. A test session consisted of four presentation phases (1st exposure to stimulus, post exposure, 2nd exposure, and access to reward). Heart rate (HR) and heart rate variability (HRV) responses were recorded during testing in the experimental room and also when lying resting in a quiet familiar room. A new method of 'stitching' short periods of HRV data together was used in the analysis. When testing different stimuli, no significant differences were observed in HR and LF:HF ratio (relative power in low frequency (LF) and the high-frequency (HF) range), implying that the sympathetic tone was activated similarly for all the stimuli and may suggest that dogs were in a state of positive arousal. A decrease of HF was associated with the meatball stimulus compared to the food pellet and the reward phase (interacting with the person or eating the food) was associated with a decrease in HF and RMSSD (root mean square of successive differences of inter-beat intervals) compared to the preceding phase (looking at the person or food). This suggests that parasympathetic deactivation is associated with a more positive emotional state in the dog. A similar reduction

  19. Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots

    NASA Astrophysics Data System (ADS)

    Georgieva, A. E.; Payne, S. J.; Moulden, M.; Redman, C. W. G.

    2010-10-01

    Electronic fetal heart rate (FHR) recording is a standard way of monitoring fetal health in labor. Decelerations and accelerations usually indicate fetal distress and normality respectively. But one type of acceleration may differ, namely an overshoot that may atypically reflect fetal stress. Here we describe a new method for detecting decelerations, accelerations and overshoots as part of a novel system for computerized FHR analysis (OxSyS). There was poor agreement between clinicians when identifying these FHR features visually, which precluded setting a gold standard of interpretation. We therefore introduced `modified' Sensitivity (SE°) and `modified' Positive Predictive Value (PPV°) as appropriate performance measures with which the algorithm was optimized. The relation between overshoots and fetal compromise in labor was studied in 15 cases and 15 controls. Overshoots showed promise as an indicator of fetal compromise. Unlike ordinary accelerations, overshoots cannot be considered to be reassuring features of fetal health.

  20. Breathing frequency bias in fractal analysis of heart rate variability.

    PubMed

    Perakakis, Pandelis; Taylor, Michael; Martinez-Nieto, Eduardo; Revithi, Ioanna; Vila, Jaime

    2009-09-01

    Detrended Fluctuation Analysis (DFA) is an algorithm widely used to determine fractal long-range correlations in physiological signals. Its application to heart rate variability (HRV) has proven useful in distinguishing healthy subjects from patients with cardiovascular disease. In this study we examined the effect of respiratory sinus arrhythmia (RSA) on the performance of DFA applied to HRV. Predictions based on a mathematical model were compared with those obtained from a sample of 14 normal subjects at three breathing frequencies: 0.1Hz, 0.2Hz and 0.25Hz. Results revealed that: (1) the periodical properties of RSA produce a change of the correlation exponent in HRV at a scale corresponding to the respiratory period, (2) the short-term DFA exponent is significantly reduced when breathing frequency rises from 0.1Hz to 0.2Hz. These findings raise important methodological questions regarding the application of fractal measures to short-term HRV. PMID:19559748

  1. Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots

    SciTech Connect

    Georgieva, A. E.; Payne, S. J.; Moulden, M.; Redman, C. W. G.

    2010-10-25

    Electronic fetal heart rate (FHR) recording is a standard way of monitoring fetal health in labor. Decelerations and accelerations usually indicate fetal distress and normality respectively. But one type of acceleration may differ, namely an overshoot that may atypically reflect fetal stress. Here we describe a new method for detecting decelerations, accelerations and overshoots as part of a novel system for computerized FHR analysis (OxSyS). There was poor agreement between clinicians when identifying these FHR features visually, which precluded setting a gold standard of interpretation. We therefore introduced 'modified' Sensitivity (SE deg.) and 'modified' Positive Predictive Value (PPV deg.) as appropriate performance measures with which the algorithm was optimized. The relation between overshoots and fetal compromise in labor was studied in 15 cases and 15 controls. Overshoots showed promise as an indicator of fetal compromise. Unlike ordinary accelerations, overshoots cannot be considered to be reassuring features of fetal health.

  2. Heart Rate Variability Dynamics for the Prognosis of Cardiovascular Risk

    PubMed Central

    Ramirez-Villegas, Juan F.; Lam-Espinosa, Eric; Ramirez-Moreno, David F.; Calvo-Echeverry, Paulo C.; Agredo-Rodriguez, Wilfredo

    2011-01-01

    Statistical, spectral, multi-resolution and non-linear methods were applied to heart rate variability (HRV) series linked with classification schemes for the prognosis of cardiovascular risk. A total of 90 HRV records were analyzed: 45 from healthy subjects and 45 from cardiovascular risk patients. A total of 52 features from all the analysis methods were evaluated using standard two-sample Kolmogorov-Smirnov test (KS-test). The results of the statistical procedure provided input to multi-layer perceptron (MLP) neural networks, radial basis function (RBF) neural networks and support vector machines (SVM) for data classification. These schemes showed high performances with both training and test sets and many combinations of features (with a maximum accuracy of 96.67%). Additionally, there was a strong consideration for breathing frequency as a relevant feature in the HRV analysis. PMID:21386966

  3. Quantification of fetal heart rate regularity using symbolic dynamics

    NASA Astrophysics Data System (ADS)

    van Leeuwen, P.; Cysarz, D.; Lange, S.; Geue, D.; Groenemeyer, D.

    2007-03-01

    Fetal heart rate complexity was examined on the basis of RR interval time series obtained in the second and third trimester of pregnancy. In each fetal RR interval time series, short term beat-to-beat heart rate changes were coded in 8bit binary sequences. Redundancies of the 28 different binary patterns were reduced by two different procedures. The complexity of these sequences was quantified using the approximate entropy (ApEn), resulting in discrete ApEn values which were used for classifying the sequences into 17 pattern sets. Also, the sequences were grouped into 20 pattern classes with respect to identity after rotation or inversion of the binary value. There was a specific, nonuniform distribution of the sequences in the pattern sets and this differed from the distribution found in surrogate data. In the course of gestation, the number of sequences increased in seven pattern sets, decreased in four and remained unchanged in six. Sequences that occurred less often over time, both regular and irregular, were characterized by patterns reflecting frequent beat-to-beat reversals in heart rate. They were also predominant in the surrogate data, suggesting that these patterns are associated with stochastic heart beat trains. Sequences that occurred more frequently over time were relatively rare in the surrogate data. Some of these sequences had a high degree of regularity and corresponded to prolonged heart rate accelerations or decelerations which may be associated with directed fetal activity or movement or baroreflex activity. Application of the pattern classes revealed that those sequences with a high degree of irregularity correspond to heart rate patterns resulting from complex physiological activity such as fetal breathing movements. The results suggest that the development of the autonomic nervous system and the emergence of fetal behavioral states lead to increases in not only irregular but also regular heart rate patterns. Using symbolic dynamics to

  4. Heart rate variability and target organ damage in hypertensive patients

    PubMed Central

    2012-01-01

    Background We evaluated the association between linear standard Heart Rate Variability (HRV) measures and vascular, renal and cardiac target organ damage (TOD). Methods A retrospective analysis was performed including 200 patients registered in the Regione Campania network (aged 62.4 ± 12, male 64%). HRV analysis was performed by 24-h holter ECG. Renal damage was assessed by estimated glomerular filtration rate (eGFR), vascular damage by carotid intima-media thickness (IMT), and cardiac damage by left ventricular mass index. Results Significantly lower values of the ratio of low to high frequency power (LF/HF) were found in the patients with moderate or severe eGFR (p-value < 0.001). Similarly, depressed values of indexes of the overall autonomic modulation on heart were found in patients with plaque compared to those with a normal IMT (p-value <0.05). These associations remained significant after adjustment for other factors known to contribute to the development of target organ damage, such as age. Moreover, depressed LF/HF was found also in patients with left ventricular hypertrophy but this association was not significant after adjustment for other factors. Conclusions Depressed HRV appeared to be associated with vascular and renal TOD, suggesting the involvement of autonomic imbalance in the TOD. However, as the mechanisms by which abnormal autonomic balance may lead to TOD, and, particularly, to renal organ damage are not clearly known, further prospective studies with longitudinal design are needed to determine the association between HRV and the development of TOD. PMID:23153340

  5. Effect of bucindolol on heart failure outcomes and heart rate response in patients with reduced ejection fraction heart failure and atrial fibrillation

    PubMed Central

    Kao, David P.; Davis, Gordon; Aleong, Ryan; O'Connor, Christopher M.; Fiuzat, Mona; Carson, Peter E.; Anand, Inder S.; Plehn, Jonathan F.; Gottlieb, Stephen S.; Silver, Marc A.; Lindenfeld, JoAnn; Miller, Alan B.; White, Michel; Murphy, Guinevere A.; Sauer, Will; Bristow, Michael R.

    2013-01-01

    Aims There is little evidence of beta-blocker treatment benefit in patients with heart failure and reduced left ventricular ejection fraction (HFREF) and atrial fibrillation (AF). We investigated the effects of bucindolol in HFREF patients with AF enrolled in the Beta-blocker Evaluation of Survival Trial (BEST). Methods and results A post-hoc analysis of patients in BEST with and without AF was performed to estimate the effect of bucindolol on mortality and hospitalization. Patients were also evaluated for treatment effects on heart rate and the influence of beta1-adrenergic receptor position 389 (β1389) arginine (Arg) vs. glycine (Gly) genotypes. In the 303/2708 patients in AF, patients receiving bucindolol were more likely to achieve a resting heart rate ≤80 b.p.m. at 3 months (P < 0.005) in the absence of treatment-limiting bradycardia. In AF patients and sinus rhythm (SR) patients who achieved a resting heart rate ≤80 b.p.m., there were beneficial treatment effects on cardiovascular mortality/cardiovascular hospitalization [hazard ratio (HR) 0.61, P = 0.025, and 0.79, P = 0.002]. Without achieving a resting heart rate ≤80 b.p.m., there were no treatment effects on events in either group. β1389-Arg/Arg AF patients had nominally significant reductions in all-cause mortality/HF hospitalization and cardiovascular mortality/hospitalization with bucindolol (HR 0.23, P = 0.037 and 0.28, P = 0.039), whereas Gly carriers did not. There was no evidence of diminished heart rate response in β1389-Arg homozygotes. Conclusion In HFREF patients with AF, bucindolol was associated with reductions in composite HF endpoints in those who achieved a resting heart rate ≤80 b.p.m. and nominally in those with the β1389-Arg homozygous genotype. PMID:23223178

  6. Heart rate variability interventions for concussion and rehabilitation

    PubMed Central

    Conder, Robert L.; Conder, Alanna A.

    2014-01-01

    The study of heart rate variability (HRV) has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain). It is well-established that lack of HRV implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal HRV has been associated with good cardiovascular health, autonomic nervous system (ANS) control, emotional regulation, and enhanced neurocognitive processing. In addition to health benefits, optimal HRV has been shown to improve neurocognitive performance by enhancing focus, visual acuity and readiness, and by promoting emotional regulation needed for peak performance. In concussed athletes and soldiers, concussions not only alter brain connectivity, but also alter cardiac functioning and impair cardiovascular performance upon exertion. Altered sympathetic and parasympathetic balance in the ANS has been postulated as a critical factor in refractory post concussive syndrome (PCS). This article will review both the pathological aspects of reduced HRV on athletic performance, as well as the cardiovascular and cerebrovascular components of concussion and PCS. Additionally, this article will review interventions with HRV biofeedback (HRV BFB) training as a promising and underutilized treatment for sports and military-related concussion. Finally, this article will review research and promising case studies pertaining to use of HRV BFB for enhancement of cognition and performance, with applicability to concussion rehabilitation. PMID:25165461

  7. Heart rate variability interventions for concussion and rehabilitation.

    PubMed

    Conder, Robert L; Conder, Alanna A

    2014-01-01

    The study of heart rate variability (HRV) has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain). It is well-established that lack of HRV implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal HRV has been associated with good cardiovascular health, autonomic nervous system (ANS) control, emotional regulation, and enhanced neurocognitive processing. In addition to health benefits, optimal HRV has been shown to improve neurocognitive performance by enhancing focus, visual acuity and readiness, and by promoting emotional regulation needed for peak performance. In concussed athletes and soldiers, concussions not only alter brain connectivity, but also alter cardiac functioning and impair cardiovascular performance upon exertion. Altered sympathetic and parasympathetic balance in the ANS has been postulated as a critical factor in refractory post concussive syndrome (PCS). This article will review both the pathological aspects of reduced HRV on athletic performance, as well as the cardiovascular and cerebrovascular components of concussion and PCS. Additionally, this article will review interventions with HRV biofeedback (HRV BFB) training as a promising and underutilized treatment for sports and military-related concussion. Finally, this article will review research and promising case studies pertaining to use of HRV BFB for enhancement of cognition and performance, with applicability to concussion rehabilitation. PMID:25165461

  8. Concurrent validity of the Armour39 heart rate monitor strap.

    PubMed

    Flanagan, Shawn D; Comstock, Brett A; Dupont, William H; Sterczala, Adam R; Looney, Dave P; Dombrowski, Dylan H; McDermott, Danielle M; Bryce, Alexander; Maladouangdock, Jesse; Dunn-Lewis, Courtenay; Luk, Hui-Ying; Szivak, Tunde K; Hooper, David R; Kraemer, William J

    2014-03-01

    New technology offers potential advantages in physically demanding environments where convenience and comfort are important and accurate and reliable data collection is challenging. Nevertheless, it is important to validate the accuracy and reliability of such biological monitoring systems (BMS) before they are adopted. The purpose of this investigation was to assess the concurrent validity of a new heart rate monitor across a range of exercise intensities and with a large and diverse group of male subjects in a large cohort with diverse physical fitness characteristics. Seventy-five men (age, 23 ± 4 years; height, 181 ± 8 cm; body mass, 83 ± 12 kg; estimated V[Combining Dot Above]O2peak, 3.16 ± 0.63 [L·min]) volunteered and completed a graded cycle ergometer exercise protocol while heart rate was continuously monitored before, during, and after exercise with the new device (Armour39) and the gold standard (electrocardiogram). The 2-minute stages included sitting, standing, and cycling with 35 W increments until volitional fatigue. The coefficient of determination between mean heart rate values at each stage was R = 0.99, whereas Pearson correlations (r) at each stage were ≥ 0.99. Heart rates during exercise were typically within 1 beat of each other. The Armour39 BMS, therefore, is an acceptable means for the valid and reliable determination of heart rate under various bodily positions and levels of exertion, including maximal exercise intensity. PMID:23860286

  9. Heart rate detection from an electronic weighing scale.

    PubMed

    González-Landaeta, R; Casas, O; Pallàs-Areny, R

    2007-01-01

    We propose a novel technique for heart rate detection on a subject that stands on a common electronic weighing scale. The detection relies on sensing force variations related to the blood acceleration in the aorta, works even if wearing footwear, and does not require any sensors attached to the body. We have applied our method to three different weighing scales, and estimated whether their sensitivity and frequency response suited heart rate detection. Scale sensitivities were from 490 nV/V/N to 1670 nV/V/N, all had an underdamped transient response and their dynamic gain error was below 19% at 10 Hz, which are acceptable values for heart rate estimation. We also designed a pulse detection system based on off-the-shelf integrated circuits, whose gain was about 70x10(3) and able to sense force variations about 240 mN. The signal-to-noise ratio (SNR) of the main peaks of the pulse signal detected was higher than 48 dB, which is large enough to estimate the heart rate by simple signal processing methods. To validate the method, the ECG and the force signal were simultaneously recorded on 12 volunteers. The maximal error obtained from heart rates determined from these two signals was +/-0.6 beats/minute. PMID:18003457

  10. The Use of Heart Rate Monitors in Physical Education

    ERIC Educational Resources Information Center

    Nichols, Randall; Davis, Kathryn L.; McCord, Tim; Schmidt, Dave; Slezak, Alex M.

    2009-01-01

    The ever-rising rate of obesity and the need for increased physical activity for young children is well documented. Data suggests that today's youth are not participating in enough quality health-enhancing physical activity either in or outside of school. Heart rate monitors have been used by adult exercisers for many years to monitor and assess…

  11. Heart rate and heart rate variability in pregnant dairy cows and their fetuses determined by fetomaternal electrocardiography.

    PubMed

    Trenk, Lisa; Kuhl, Juliane; Aurich, Jörg; Aurich, Christine; Nagel, Christina

    2015-11-01

    In this study, fetomaternal electrocardiograms were recorded once weekly in cattle during the last 14 weeks of gestation. From the recorded beat-to-beat (RR) intervals, heart rate and heart rate variability (HRV) variables standard deviation of the RR interval (SDRR) and root mean square of successive RR differences (RMSSD) were calculated. To differentiate between effects of lactation and gestation, pregnant lactating (PL) cows (n = 7) and pregnant nonlactating (PNL) heifers (n = 8) were included. We hypothesized that lactation is associated with stress detectable by HRV analysis. We also followed the hypothesis that heart rate and HRV are influenced by growth and maturation of the fetus toward term. Maternal heart rate changed over time in both groups, and in PL cows, it decreased with drying-off. During the last 5 weeks of gestation, maternal heart rate increased in both groups but was lower in PL cows than in PNL heifers. Maternal HRV did not change over time, but SDRR was significantly higher in PL cows than in PNL heifers, and significant interactions of group × time existed. On the basis of HRV, undisturbed pregnancies are thus no stressor for the dam in cattle. Fetal heart rate decreased from week 14 to week 1 before birth with no difference between groups. Gestational age thus determines heart rate in the bovine fetus. The HRV variables SDRR and RMSSD increased toward the end of gestation in fetuses carried by cows but not in those carried by heifers. The increase in HRV indicates maturation of fetal cardiac regulation which may be overrun by high sympathoadrenal activity in fetuses carried by heifers as suggested by their low HRV. PMID:26279313

  12. Metabolic rate, heart rate, and tailbeat frequency during sustained swimming in the leopard shark Triakis semifasciata.

    PubMed

    Scharold, J; Lai, N C; Lowell, W R; Graham, J B

    1989-01-01

    Heart rate, metabolic rate, and tailbeat frequency were simultaneously recorded from seven leopard sharks (Triakis semifasciata) during steady swimming at controlled speeds to evaluate the usefulness of heart rate as a measure of field metabolic rate. Heart rate was monitored by acoustic telemetry using a frequency modulated ECG transmitter. Metabolic rate was measured as oxygen consumption in a swimming tunnel respirometer. For instrumented sharks, mean resting oxygen consumption rate and heart rate were 105.3 +/- 35.6 (SE) mg O2.kg-1.h-1 and 36.6 +/- 1.8 (SE) beats.min-1, respectively. While swimming at the maximum sustained speed (0.84 +/- 0.03 lengths.s-1) for 30-60 min, these rates were 229.3 +/- 13.2 mg O2.kg-1.h-1 and 46.9 +/- 0.9 beats.min-1. Although a significant linear regression was obtained between metabolic rate and heart rate, a low overall correlation coefficient may result from the existence of separate individual regressions and confounding changes in stroke volume and/or arteriovenous oxygen difference. Heart rate was approximately as closely correlated with oxygen consumption rate as swimming speed was. A significant linear relationship was obtained between tailbeat frequency and swimming speed to speeds of 0.75 lengths.s-1. PMID:2776865

  13. Visualization of Heart Rate Variability of Long-Term Heart Transplant Patient by Transition Networks: A Case Report

    PubMed Central

    Wdowczyk, Joanna; Makowiec, Danuta; Dorniak, Karolina; Gruchała, Marcin

    2016-01-01

    We present a heart transplant patient at his 17th year of uncomplicated follow-up. Within a frame of routine check out several tests were performed. With such a long and uneventful follow-up some degree of graft reinnervation could be anticipated. However, the patient's electrocardiogram and exercise parameters seemed largely inconclusive in this regard. The exercise heart rate dynamics were suggestive of only mild, if any parasympathetic reinnervation of the graft with persisting sympathetic activation. On the other hand, traditional heart rate variability (HRV) indices were inadequately high, due to erratic rhythm resulting from interference of the persisting recipient sinus node or non-conducted atrial parasystole. New tools, originated from network representation of time series, by visualization short-term dynamical patterns, provided a method to discern HRV increase due to reinnervation from other reasons. PMID:27014081

  14. Visualization of Heart Rate Variability of Long-Term Heart Transplant Patient by Transition Networks: A Case Report.

    PubMed

    Wdowczyk, Joanna; Makowiec, Danuta; Dorniak, Karolina; Gruchała, Marcin

    2016-01-01

    We present a heart transplant patient at his 17th year of uncomplicated follow-up. Within a frame of routine check out several tests were performed. With such a long and uneventful follow-up some degree of graft reinnervation could be anticipated. However, the patient's electrocardiogram and exercise parameters seemed largely inconclusive in this regard. The exercise heart rate dynamics were suggestive of only mild, if any parasympathetic reinnervation of the graft with persisting sympathetic activation. On the other hand, traditional heart rate variability (HRV) indices were inadequately high, due to erratic rhythm resulting from interference of the persisting recipient sinus node or non-conducted atrial parasystole. New tools, originated from network representation of time series, by visualization short-term dynamical patterns, provided a method to discern HRV increase due to reinnervation from other reasons. PMID:27014081

  15. Cardiovascular and Cerebrovascular Control on Return from International Space Station (CCISS)- Heart Rate and Activity

    NASA Astrophysics Data System (ADS)

    Hughson, R. L.; Shoemaker, J. K.; Blaber, A. P.; Arbeille, Ph.; Zuj, K. A.; Greaves, D. K.

    2008-06-01

    CCISS is a project to study the cardiovascular and cerebrovascular responses of astronauts before, during and after long-duration (>60-day) stays on the International Space Station. The CCISS experiments consist of three phases that are designed to achieve an integrated examination of components responsible for return of blood to the heart, the pumping of blood from the heart and the distribution to the vascular territories including the brain. In this report the data are obtained from the 24-h monitoring of physical activity (Actiwatch on wrist and ankle) and of heart rate (Holter monitor). The data show clear patterns of change in physical activity from predominantly leg-based on Earth to relatively little activity of the ankles with maintained or increased activity of the wrists on ISS. Both on Earth and on ISS the largest changes in heart rate occur during the periods of leg activity. Average heart rate was changed little during the periods of minimal activity or of sleep in comparisons of Earth with in-flight recording both within the first two weeks of flight and the last two weeks. These data clearly show the importance of monitoring heart rate and physical activity simultaneously and show that attempts to derive indicators of autonomic activity from spectral analysis of heart rate variability should not be performed in the absence of knowledge of both variables.

  16. Kramers-Moyal Expansion of Heart Rate Variability

    NASA Astrophysics Data System (ADS)

    Petelczyc, M.; Żebrowski, J. J.; Baranowski, R.

    2009-05-01

    The first six Kramers-Moyal coefficients were extracted from human heart rate variability recordings. The method requires the determination of the Markov time and of the proper conditional probability densities. We analyzed heart rate data recorded in a group of ten young, healthy subjects. We obtained non-negligible higher order Kramers-Moyal (K-M) terms in 6 h nighttime parts of the 24 h recordings. This indicates that the data is a non-Gaussian process and probably a correlated signal. The analysis yielded important new insights into the character and distribution of the stochastic processes measured in healthy group. In the night hours, the dominant oscillation in the heart rate is the so called respiratory sinus arrhythmia (RSA) -- a physiological phenomenon in which respiration acts as a drive for the heart rate. Certain kinds of pathology may disrupt RSA. We compared nighttime recordings of the healthy group with those recorded in six patients with hypertrophic cardiomyopathy (HCM). HCM is generally a pathology of heart cells but abnormalities in autonomic regulation are also observed. Using the higher order Kramers-Moyal coefficients, we analyzed the skewness and kurtosis in the nighttime recordings for the normal subjects.

  17. Universal structures of normal and pathological heart rate variability

    PubMed Central

    Gañán-Calvo, Alfonso M.; Fajardo-López, Juan

    2016-01-01

    The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient. PMID:26912108

  18. Reliability of spectral analysis of fetal heart rate variability.

    PubMed

    Warmerdam, G J J; Vullings, R; Bergmans, J W M; Oei, S G

    2014-01-01

    Spectral analysis of fetal heart rate variability could provide information on fetal wellbeing. Unfortunately, fetal heart rate recordings are often contaminated by artifacts. Correction of these artifacts affects the outcome of spectral analysis, but it is currently unclear what level of artifact correction facilitates reliable spectral analysis. In this study, a method is presented that estimates the error in spectral powers due to artifact correction, based on the properties of the Continuous Wavelet Transformation. The results show that it is possible to estimate the error in spectral powers. The information about this error makes it possible for clinicians to assess the reliability of spectral analysis of fetal heart rate recordings that are contaminated by artifacts. PMID:25570577

  19. Exaggerated heart rate oscillations during two meditation techniques.

    PubMed

    Peng, C K; Mietus, J E; Liu, Y; Khalsa, G; Douglas, P S; Benson, H; Goldberger, A L

    1999-07-31

    We report extremely prominent heart rate oscillations associated with slow breathing during specific traditional forms of Chinese Chi and Kundalini Yoga meditation techniques in healthy young adults. We applied both spectral analysis and a novel analytic technique based on the Hilbert transform to quantify these heart rate dynamics. The amplitude of these oscillations during meditation was significantly greater than in the pre-meditation control state and also in three non-meditation control groups: i) elite athletes during sleep, ii) healthy young adults during metronomic breathing, and iii) healthy young adults during spontaneous nocturnal breathing. This finding, along with the marked variability of the beat-to-beat heart rate dynamics during such profound meditative states, challenges the notion of meditation as only an autonomically quiescent state. PMID:10454297

  20. Universal structures of normal and pathological heart rate variability.

    PubMed

    Gañán-Calvo, Alfonso M; Fajardo-López, Juan

    2016-01-01

    The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient. PMID:26912108

  1. Robust efficient estimation of heart rate pulse from video

    PubMed Central

    Xu, Shuchang; Sun, Lingyun; Rohde, Gustavo Kunde

    2014-01-01

    We describe a simple but robust algorithm for estimating the heart rate pulse from video sequences containing human skin in real time. Based on a model of light interaction with human skin, we define the change of blood concentration due to arterial pulsation as a pixel quotient in log space, and successfully use the derived signal for computing the pulse heart rate. Various experiments with different cameras, different illumination condition, and different skin locations were conducted to demonstrate the effectiveness and robustness of the proposed algorithm. Examples computed with normal illumination show the algorithm is comparable with pulse oximeter devices both in accuracy and sensitivity. PMID:24761294

  2. Generalised heart rate statistics reveal neurally mediated homeostasis transients

    NASA Astrophysics Data System (ADS)

    Makowiec, D.; Graff, B.; Miklaszewski, W.; Wejer, D.; Kaczkowska, A.; Budrejko, S.; Struzik, Z. R.

    2015-04-01

    Distributions of accelerations and decelerations, obtained from increments of heart rate recorded during a head-up tilt table (HUTT) test provide short-term characterization of the complex cardiovascular response to a rapid controlled dysregulation of homeostasis. A generalised statistic is proposed for evaluating the neural reflexes responsible for restoring the homeostatic dynamics. An evaluation of the effects on heart rate of the neural regulation involved in achieving homeostasis indicates a distinction between vasovagal patients and healthy subjects who are not susceptible to spontaneous fainting. A healthy cardiovascular response to the HUTT test is identified in the sympathetic tone appropriately punctuated by vagal activity.

  3. Increased Heart Rate Variability but Normal Resting Metabolic Rate in Hypocretin/Orexin-Deficient Human Narcolepsy

    PubMed Central

    Fronczek, Rolf; Overeem, Sebastiaan; Reijntjes, Robert; Lammers, Gert Jan; van Dijk, J. Gert; Pijl, Hanno

    2008-01-01

    Study Objectives: We investigated autonomic balance and resting metabolic rate to explore their possible involvement in obesity in hypocretin/orexin-deficient narcoleptic subjects. Methods: Resting metabolic rate (using indirect calorimetry) and variability in heart rate and blood pressure were determined in the fasted resting state. Subjects included 15 untreated, hypocretin-deficient male narcoleptics and 15 male controls matched for age and body mass index. Results: Spectral power analysis revealed greater heart rate and blood pressure variability in hypocretin-deficient male narcoleptic patients (heart rate: p = 0.01; systolic blood pressure: p = 0.02; diastolic: p < 0.01). The low to high frequency ratio of heart rate power did not differ between groups (p = 0.48), nor did resting metabolic rate (controls: 1767 ± 226 kcal/24 h; patients: 1766 ± 227 kcal/24h; p = 0.99). Conclusions: Resting metabolic rate was not reduced in hypocretin-deficient narcoleptic men and therefore does not explain obesity in this group. Whether the increased heart rate and blood pressure variability—suggesting reduced sympathetic tone—is involved in this regard remains to be elucidated. Citation: Fronczek R; Overeem S; Reijntjes R; Lammers GJ; van Dijk JG; Pijl H. Increased heart rate variability but normal resting metabolic rate in hypocretin/orexin-deficient human narcolepsy. J Clin Sleep Med 2008;4(3):248–254. PMID:18595438

  4. Heart rate variability and cognitive function: effects of physical effort.

    PubMed

    Luft, Caroline Di Bernardi; Takase, Emílio; Darby, David

    2009-10-01

    This study investigated alterations in heart rate variability (HRV) and cognitive performance before and after physical effort, for 30 high-level track and field athletes (23 males and 7 females). Interbeat intervals were assessed at the baseline and during each task of a CogState cognitive battery (simple reaction time, choice reaction time, working memory, short-term memory and sustained attention). Time and frequency domain measures of HRV were compared between conditions and between tasks. The results indicated differences in HRV between executive and non-executive tasks. There was a significant increase in sympathetic-modulation-related indices after physical effort. The differences between executive and non-executive tasks were the same in post-test. Correlations were found between HRV and cognitive performance, which differed by speed and accuracy. We conclude that HRV is related to cognitive demand and that the correlation between HRV and cognitive performance seems to be stronger after physical exercise. The results raise questions about the psychophysiological meaning of different HRV signals and this has implications for future research about the relationship between HRV and cognition. PMID:19632295

  5. Voluntary heart rate reduction following yoga using different strategies

    PubMed Central

    Raghavendra, BR; Telles, S; Manjunath, NK; Deepak, KK; Naveen, KV; Subramanya, P

    2013-01-01

    Background/Aims: One month of yoga training has been shown to reduce the pulse rate voluntarily without using external cues. Hence, the present study was designed to understand the strategies used by yoga practitioners and autonomic changes associated with voluntary heart rate reduction. Materials and Methods: Fifty volunteers (group mean age ± S.D., 25.4 ± 4.8 years; 25 males) were assessed in two trials on separate days. Each trial was for 12 minutes, with a ‘pre’ state and ‘during’ state of 6 minutes each. For both trials the ‘pre’ state was relaxation with eyes closed. In the ‘during’ state of Trial I, subjects were asked to voluntarily reduce their heart rate using a strategy of their choice. From their responses to specific questions it was determined that 22 out of 50 persons used breath regulation as a strategy. Hence, in the ‘during’ state of Trial II, subjects were asked to voluntarily reduce their heart rate by breath regulation. Results: In the first trial, the heart rate was reduced by an average of 19.6 beats per minute and in the second trial (with breath regulation exclusively) an average decrease of 22.2 beats per minute was achieved. Conclusions: Hence, the strategy used did not markedly alter the outcome. PMID:23440267

  6. Diving behaviour and heart rate in tufted ducks (Aythya fuligula).

    PubMed

    Stephenson, R; Butler, P J; Woakes, A J

    1986-11-01

    Diving behaviour and heart rate were monitored in tufted ducks diving under circumstances which simulated various environmental conditions such as feeding under ice in winter. When distance to food was increased on a covered outdoor pond, dive duration increased proportionately, but it was calculated that time available for feeding was reduced during the longer-distance 'extended' dives. There was a gradual reduction in heart rate to 77.3 +/- 13.8 beats min-1, which is significantly lower than the resting value of 121.1 +/- 14.1 beats min-1, during the course of extended dives, suggesting that the ducks could gradually switch over to a 'classical' oxygen-conserving response during these prolonged voluntary dives. The duration of the pre-dive preparatory period was positively correlated with dive distance. When the ducks were briefly unable to resurface during an otherwise normal feeding dive in an indoor tank, a situation which may occur if they become disoriented under ice, there was an immediate switch to a full bradycardia. Reduction in heart rate during these 'enclosed' dives occurred only when the ducks were apparently aware of the situation and the rate of onset of bradycardia was very similar to that previously observed during involuntary submersion of tufted ducks. Minimum heart rate was the same at 46 beats min-1 after 15 s of enclosed dives and after 30 s of involuntary submersions, despite the differences in levels of activity in the two situations. PMID:3805996

  7. Effect of heart rate on the hemodynamics of bileaflet mechanical heart valves' prostheses (St. Jude Medical) in the aortic position and in the opening phase: A computational study.

    PubMed

    Jahandardoost, Mehdi; Fradet, Guy; Mohammadi, Hadi

    2016-03-01

    To date, to the best of the authors' knowledge, in almost all of the studies performed around the hemodynamics of bileaflet mechanical heart valves, a heart rate of 70-72 beats/min has been considered. In fact, the heart rate of ~72 beats/min does not represent the entire normal physiological conditions under which the aortic or prosthetic valves function. The heart rates of 120 or 50 beats/min may lead to hemodynamic complications, such as plaque formation and/or thromboembolism in patients. In this study, the hemodynamic performance of the bileaflet mechanical heart valves in a wide range of normal and physiological heart rates, that is, 60-150 beats/min, was studied in the opening phase. The model considered in this study was a St. Jude Medical bileaflet mechanical heart valve with the inner diameter of 27 mm in the aortic position. The hemodynamics of the native valve and the St. Jude Medical valve were studied in a variety of heart rates in the opening phase and the results were carefully compared. The results indicate that peak values of the velocity profile downstream of the valve increase as heart rate increases, as well as the location of the maximum velocity changes with heart rate in the St. Jude Medical valve model. Also, the maximum values of shear stress and wall shear stresses downstream of the valve are proportional to heart rate in both models. Interestingly, the maximum shear stress and wall shear stress values in both models are in the same range when heart rate is <90 beats/min; however, these values significantly increase in the St. Jude Medical valve model when heart rate is >90 beats/min (up to ~40% growth compared to that of the native valve). The findings of this study may be of importance in the hemodynamic performance of bileaflet mechanical heart valves. They may also play an important role in design improvement of conventional prosthetic heart valves and the design of the next generation of prosthetic valves, such as

  8. [Changes in heart rate variability after myocardial infarction. Value of Poincareé's diagram].

    PubMed

    Copie, X; Le Heuzey, J Y; Iliou, M C; Pousset, F; Lavergne, T; Guize, L

    1995-11-01

    The variability of the heart rate is reduced after myocardial infarction. It then progressively increases, to return to near normal values after several months. However, these changes in heart rate variability occur at the same time as slowing of the heart rate which makes interpretation difficult. Poincaré's diagram is constructed from a Holter recording plotting each RR interval against the preceding RR interval. The authors have developed a geometric approach to this diagram to evaluate parasympathetic tone for a given heart rate. By measuring the dispersion in height of the Poincaré's diagram, the authors evaluate the shor-term variability for a given RR interval. Two 24 hr Holter recordings were performed in 52 patients at one and two weeks after a myocardial infarction. The dispersion in the height of the Poincaré's diagrams was measured at the 10th, 25th, 50th, 75th and 90th percentiles of the total dispersion. The authors have shown an increase in the short-term variability of the shortest RR intervals (1th, 25th and 50th percentiles) which is not observed in the longer RR intervals (75th and 90th percentiles). In conclusion, theres is an increase in the heart rate variability at the shortest RR intervals. This suggests that the recovery of parasympathic tone after myocardial infarction occurs mainly at the fastest heart rates. PMID:8745997

  9. Heart Rate Detection During Sleep Using a Flexible RF Resonator and Injection-Locked PLL Sensor.

    PubMed

    Kim, Sung Woo; Choi, Soo Beom; An, Yong-Jun; Kim, Byung-Hyun; Kim, Deok Won; Yook, Jong-Gwan

    2015-11-01

    Novel nonintrusive technologies for wrist pulse detection have been developed and proposed as systems for sleep monitoring using three types of radio frequency (RF) sensors. The three types of RF sensors for heart rate measurement on wrist are a flexible RF single resonator, array resonators, and an injection-locked PLL resonator sensor. To verify the performance of the new RF systems, we compared heart rates between presleep time and postsleep onset time. Heart rates of ten subjects were measured using the RF systems during sleep. All three RF devices detected heart rates at 0.2 to 1 mm distance from the skin of the wrist over clothes made of cotton fabric. The wrist pulse signals of a flexible RF single resonator were consistent with the signals obtained by a portable piezoelectric transducer as a reference. Then, we confirmed that the heart rate after sleep onset time significantly decreased compared to before sleep. In conclusion, the RF system can be utilized as a noncontact nonintrusive method for measuring heart rates during sleep. PMID:26057527

  10. Estimating Energy Expenditure from Heart Rate in Older Adults: A Case for Calibration

    PubMed Central

    Schrack, Jennifer A.; Zipunnikov, Vadim; Goldsmith, Jeff; Bandeen-Roche, Karen; Crainiceanu, Ciprian M.; Ferrucci, Luigi

    2014-01-01

    Background Accurate measurement of free-living energy expenditure is vital to understanding changes in energy metabolism with aging. The efficacy of heart rate as a surrogate for energy expenditure is rooted in the assumption of a linear function between heart rate and energy expenditure, but its validity and reliability in older adults remains unclear. Objective To assess the validity and reliability of the linear function between heart rate and energy expenditure in older adults using different levels of calibration. Design Heart rate and energy expenditure were assessed across five levels of exertion in 290 adults participating in the Baltimore Longitudinal Study of Aging. Correlation and random effects regression analyses assessed the linearity of the relationship between heart rate and energy expenditure and cross-validation models assessed predictive performance. Results Heart rate and energy expenditure were highly correlated (r = 0.98) and linear regardless of age or sex. Intra-person variability was low but inter-person variability was high, with substantial heterogeneity of the random intercept (s.d. = 0.372) despite similar slopes. Cross-validation models indicated individual calibration data substantially improves accuracy predictions of energy expenditure from heart rate, reducing the potential for considerable measurement bias. Although using five calibration measures provided the greatest reduction in the standard deviation of prediction errors (1.08 kcals/min), substantial improvement was also noted with two (0.75 kcals/min). Conclusion These findings indicate standard regression equations may be used to make population-level inferences when estimating energy expenditure from heart rate in older adults but caution should be exercised when making inferences at the individual level without proper calibration. PMID:24787146

  11. Direct observation of homoclinic orbits in human heart rate variability

    NASA Astrophysics Data System (ADS)

    Żebrowski, J. J.; Baranowski, R.

    2003-05-01

    Homoclinic trajectories of the interbeat intervals between contractions of ventricles of the human heart are identified. The interbeat intervals are extracted from 24-h Holter ECG recordings. Three such recordings are discussed in detail. Mappings of the measured consecutive interbeat intervals are constructed. In the second and in some cases in the fourth iterate of the map of interbeat intervals homoclinic trajectories associated with a hyperbolic saddle are found. The homoclinic trajectories are often persistent for many interbeat intervals, sometimes spanning many thousands of heartbeats. Several features typical for homoclinic trajectories found in other systems were identified, including a signature of the gluing bifurcation. The homoclinic trajectories are present both in recordings of heart rate variability obtained from patients with an increased number of arrhythmias and in cases in which the sinus rhythm is dominant. The results presented are a strong indication of the importance of deterministic nonlinear instabilities in human heart rate variability.

  12. Prediction of Heart Rates on a Ropes Course from Simple Physical Measures. Research Update.

    ERIC Educational Resources Information Center

    Priest, Simon; Montelpare, William

    1995-01-01

    This study identified the highest heart rates attained on a ropes course for a corporate population; examined relationships between highest heart rate and other physical measures (basal heart rate, blood pressure, height, weight, body girths, cholesterol, maximum number of pushups, and heart rate after brisk walk); and developed an equation for…

  13. Low-dose coronary-CT angiography using step and shoot at any heart rate: comparison of image quality at systole for high heart rate and diastole for low heart rate with a 128-slice dual-source machine.

    PubMed

    Paul, Jean-François; Amato, Aude; Rohnean, Adela

    2013-03-01

    To compare image quality of coronary CT angiography in step-and-shoot mode at the diastolic phase at low heart rates (<70 bpm) and systolic phase at high heart rates (≥70 bpm). We prospectively included 96 consecutive patients then excluded 5 patients with arrhythmia. Coronary CT-angiography was performed using a dual-source 128-slice CT machine, at the diastolic phase in the 55 patients with heart rates <70 bpm (group D) and at the systolic phase in the 36 patients with heart rates ≥70 (group S). Image quality was scored on a 5 point-scale (1, not interpretable; 2, insufficient for diagnosis; 3, fair, sufficient for diagnosis; 4, good; 5, excellent). In addition, we compared the number of stair-step artifacts in the two groups. Mean image quality score was 4 (0.78) in group D and 4.1 (0.34) in group S (NS), with an unequal distribution (p = 0.01). Step artifacts were seen in 44 % of group D and 18 % of group S patients (p = 0.02). In 3 group D patients and no group S patients, the image score was <3 due to artifacts, requiring repeat CT-angiography. When performing dual-source 128-slice CT-angiography, step-and-shoot acquisition provides comparable mean image quality in systole, with less variability and fewer stair-step artifacts, compared to diastole. This method may be feasible at any heart rate in most patients in sinus rhythm, allowing low-dose prospective acquisition without beta-blocker premedication. PMID:22918571

  14. Circadian Variation of Heart Rate Variability Across Sleep Stages

    PubMed Central

    Boudreau, Philippe; Yeh, Wei-Hsien; Dumont, Guy A.; Boivin, Diane B.

    2013-01-01

    Study Objectives: Nocturnal cardiovascular events are more frequent at the beginning and end of the night. It was proposed that this pattern reflects the nocturnal distribution of sleep and sleep stages. Using heart rate variability (HRV), we recently showed an interaction between the circadian system and vigilance states on the regulation of cardiac rhythmicity. Here, we further investigate this interaction in order to clarify the specific effects of sleep stages on the regulation of the heart. Design: Participants underwent a 72-h ultradian sleep-wake cycle procedure in time isolation consisting of alternating 60-min wake episodes in dim light and 60-min nap opportunities in total darkness. Setting: Time isolation suite. Patients or participants: Fifteen healthy young participants; two were subsequently excluded. Interventions: N/A. Measurements and Results: The current study revealed that sleep onset and progression to deeper sleep stages was associated with a shift toward greater parasympathetic modulation, whereas rapid eye movement (REM) sleep was associated with a shift toward greater sympathetic modulation. We found a circadian rhythm of heart rate (HR) and high-frequency power during wakefulness and all non-REM sleep stages. A significant circadian rhythm of HR and sympathovagal balance of the heart was also observed during REM sleep. During slow wave sleep, maximal parasympathetic modulation was observed at ∼02:00, whereas during REM sleep, maximal sympathetic modulation occurred in the early morning. Conclusion: The circadian and sleep stage-specific effects on heart rate variability are clinically relevant and contribute to the understanding of the degree of cardiovascular vulnerability during sleep. Citation: Boudreau P; Yeh WH; Dumont GA; Boivin DB. Circadian variation of heart rate variability across sleep stages. SLEEP 2013;36(12):1919-1928. PMID:24293767

  15. When heart goes “BOOM” to fast. Heart rate greater than 80 as mortality predictor in acute myocardial infarction

    PubMed Central

    Davidovic, Goran; Iric-Cupic, Violeta; Milanov, Srdjan; Dimitijevic, Aleksandra; Petrovic-Janicijevic, Mirjana

    2013-01-01

    Many prospective studies established association between high heart rate and increased cardiovascular morbidity and mortality, independently of other risk factors. Heart rate over 80 beats per minute more often leads to atherosclerotic plaque disruption, the main step in developing acute coronary syndrome. Purpose was to investigate the incidence of higher heart rate levels in patients with anterior wall acute myocardial infarction with ST-segment elevation and the influence of heart rate on mortality. Research included 140 patients with anterior wall acute myocardial infarction with ST-segment elevation treated in Coronary Unit, Clinical Center Kragujevac in the period from January 2001-June 2006. Heart rate was calculated as the mean value of baseline and heart rate in the first 30 minutes after admission. Other risk factors were also followed to determine their connection with elevated heart rate. Results showed that the majority of patients survived (over 70%). In a total number of patients, more than 75% had a heart rate levels greater than 80 beats per minute. There was a significant difference in heart rate on addmision between survivors and patients who died, with a greater levels in patients with fatal outcome. Both, univariate and multivariate regression analysis singled out heart rate greater than 80 beats per minute as independent mortality predictor in these patients. Heart rate greater than 80 beats per minute is a major, independent risk factor for morbidity and important predictor of mortality in patients with acute myocardial infarction. PMID:23991346

  16. Heart rate variability and renal organ damage in hypertensive patients.

    PubMed

    Melillo, Paolo; Izzo, Raffaele; De Luca, Nicola; Pecchia, Leandro

    2012-01-01

    Heart rate variability (HRV), a noninvasive measure of autonomic dysfunction and a risk factor for cardiovascular disease (CVD), has not been systematically studied in hypertensive patients in relation with renal involvement. A retrospective analysis on a cohort of hypertensive patients was performed to show differences in groups of patients categorized according to renal involvement, assessed by glomerular filtration rate (GFR). Patient with 24-h ECG Holter monitoring and other clinical information registered in the database of the Hypertension Clinic of the University of Naples Federico II were selected. Linear standard HRV measures were computed according to international guidelines on 24-h nominal ECG. A total of 200 patients were included in the present study. Decreased ratio of low to high frequency power (LF/HF) was associated with patient with moderate GFR, the highest grade of renal involvement considered in this study. These results were consistent with the findings of previous studies which concluded that depressed HRV was associated with higher risk of progression to end-stage renal disease and suggested that autonomic dysfunction may lead to kidney damage. Further research is needed to define the role of autonomic dysfunction in the development of renal disease and of HRV as a diagnostic or prognostic maker in hypertensive patients. PMID:23366762

  17. Heart Rate Variability During Early Adaptation to Space

    NASA Technical Reports Server (NTRS)

    Toscano, W. B.; Cowings, P. S.

    1994-01-01

    A recent report hypothesized that episodes of space motion sickness (SMS) were reliably associated with low frequency oscillations (less than 0.03 to less than 0.01 Hz) in heart rate variability. This paper archives a large data set for review of investigators in this field which may facilitate the evaluation of this hypothesis. Continuous recording of Electro-cardiography (ECG) and other measures were made for 6 to 12 hours per day (waking hours) of six Shuttle crewmembers for the first 3 mission days of two separate Shuttle flights. Spectral analyses of heart rate variability during approximately 200 hours of inflight is presented. In addition, nearly 200 hours of data collected on these same individuals during ground tests prior to the mission are presented. The Purpose of this Publication is to document the incidence of low frequency oscillations of heart rate in 4 people exposed to microgravity over a period of five days. In addition, this report contains spectral analyses of heart rate data collected on these same individuals during ground-based mission simulations. By archiving these data in this manner, it is our intention to make this information available to other investigators interested in studying this phenomena.

  18. Transfer entropy analysis of maternal and fetal heart rate coupling.

    PubMed

    Marzbanrad, Faezeh; Kimura, Yoshitaka; Endo, Miyuki; Palaniswami, Marimuthu; Khandoker, Ahsan H

    2015-08-01

    Although evidence of the short term relationship between maternal and fetal heart rates has been found in previous model-based studies, knowledge about the mechanism and patterns of the coupling during gestation is still limited. In this study, a model-free method based on Transfer Entropy (TE) was applied to quantify the maternal-fetal heart rate couplings in both directions. Furthermore, analysis of the lag at which TE was maximum and its changes throughout gestation, provided more information about the mechanism of coupling and its latency. Experimental results based on fetal electrocardiograms (fECGs) and maternal ECG showed the evidence of coupling for 62 out of 65 healthy mothers and fetuses in each direction, by statistically validating against the surrogate pairs. The fetuses were divided into three gestational age groups: early (16-25 weeks), mid (26-31 weeks) and late (32-41 weeks) gestation. The maximum TE from maternal to fetal heart rate significantly increased from early to mid gestation, while the coupling delay on both directions decreased significantly from mid to late gestation. These changes occur concomitant with the maturation of the fetal sensory and autonomic nervous systems with advancing gestational age. In conclusion, the application of TE with delays revealed detailed information about the changes in fetal-maternal heart rate coupling strength and latency throughout gestation, which could provide novel clinical markers of fetal development and well-being. PMID:26738115

  19. Relationship between Exercise Heart Rate and Music Tempo Preference

    ERIC Educational Resources Information Center

    Karageorghis, Costas I.; Jones, Leighton; Low, Daniel C.

    2006-01-01

    The present study examined the predicted positive and linear relationship (Iwanaga, 1995a, 1995b) between exercise heart rate and music tempo preference. Initially, 128 undergraduate students (M age = 20.0 years, SD = 0.9) were surveyed to establish their three favorite music artists. A separate experimental group of 29 undergraduates (M age =…

  20. Identifying chaos from heart rate: The right task?

    NASA Astrophysics Data System (ADS)

    Freitas, Ubiratan; Roulin, Elise; Muir, Jean-François; Letellier, Christophe

    2009-06-01

    Providing a conclusive answer to the question "is this dynamics chaotic?" remains very challenging when experimental data are investigated. We showed that such a task is actually a difficult problem in the case of heart rates. Nevertheless, an appropriate dynamical analysis can discriminate healthy subjects from patients.

  1. Heart Rate Monitors Promote Physical Education for Children

    ERIC Educational Resources Information Center

    Tipton, Jan; Sander, Allan N.

    2004-01-01

    National health and fitness data suggests that a significant percentage of children are not on a pathway to leading healthy, physically active lifestyles. Many children are leading sedentary lifestyles due to a lack of opportunity, success, or self-motivation in physical activity. Programs that highlight the use of heart rate monitors offer a…

  2. Exploring the Relationship between Fetal Heart Rate and Cognition

    ERIC Educational Resources Information Center

    Kisilevsky, Barbara S.; Hains, Sylvia M. J.

    2010-01-01

    A relationship between fetal heart rate (HR) and cognition is explored within the context of infant, child and adult studies where the association is well established. Lack of direct access to the fetus and maturational changes limit research paradigms and response measures for fetal studies. Nevertheless, neural regulation of HR shows a number of…

  3. Heart Rate and Stress in a College Setting

    ERIC Educational Resources Information Center

    Elwess, Nancy L.; Vogt, F. Daniel

    2005-01-01

    Conditions producing stress are present in all colleges and universities. In this paper we report on an investigation utilizing heart rate as an indicator of stress in students when participating in activities encountered in a college classroom or laboratory. The activities included presenting an oral report, taking an exam, and participating in a…

  4. 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…

  5. Fetal heart rate changes associated with general anesthesia.

    PubMed

    Fedorkow, D M; Stewart, T J; Parboosingh, J

    1989-07-01

    Decreased fetal heart rate variability was noted 90 seconds after the induction of general anesthesia with sodium thiopentone and fentanyl in a patient undergoing basket extraction of a renal calculus at 30 weeks' gestation. The fetal sleep pattern lasted for 105 minutes after the anesthetic was discontinued, 45 minutes after the mother was fully awake. PMID:2730732

  6. Heart Rate Variability and Drawing Impairment in Hypoxemic COPD

    ERIC Educational Resources Information Center

    Incalzi, Raffaele Antonelli; Corsonello, Andrea; Trojano, Luigi; Pedone, Claudio; Acanfora, Domenico; Spada, Aldo; D'Addio, Gianni; Maestri, Roberto; Rengo, Franco; Rengo, Giuseppe

    2009-01-01

    We studied 54 patients with hypoxemic chronic obstructive pulmonary disease (COPD). The Mini Mental State Examination and the Mental Deterioration Battery were used for neuropsychological assessment. Heart rate variability (HRV) was assessed based on 24-h Holter ECG recording. Mann-Whitney test was used to compare HRV parameters of patients…

  7. [The physiological problems of biofeedback control by the heart rate].

    PubMed

    Sidorov, Iu A; Vasilevskiĭ, N N

    1994-02-01

    The data on voluntary regulation of the heart rate in humans is given in respect to individual-typological differences of adaptive abilities, ecological specifics of ambient environment and labour, health condition (neuroses, vegetative-vascular dystonias etc.). A major role of training of the rhythmic regulatory processes for the biological feedback control, is corroborated. PMID:7522776

  8. Volitional Control of Heart Rate During Exercise Stress.

    ERIC Educational Resources Information Center

    LeFevers, Victoria A.

    Thirty five volunteer college women were divided into three groups to determine if heart rate could be conditioned instrumentally and lowered during exercise stress on the treadmill. The three groups were a) experimental group I, 15 subjects who received instrumental conditioning with visual feedback; b) instrumental group II, 9 subjects who…

  9. Infant Heart Rate: A Review of Research and Methodology.

    ERIC Educational Resources Information Center

    Von Bargen, Donna M.

    1983-01-01

    Reviews literature on children up to age one to determine whether heart rate (HR) is a reliable, stable, and valid measure. Considers factors influencing resting HR and the Law of Initial Values, discusses information about response to stimulation and infant perception and affect obtained by using HR measures, and describes HR use in risk…

  10. An improved method of measuring heart rate using a webcam

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Ouyang, Jianfei; Yan, Yonggang

    2014-09-01

    Measuring heart rate traditionally requires special equipment and physical contact with the subject. Reliable non-contact and low-cost measurements are highly desirable for convenient and comfortable physiological self-assessment. Previous work has shown that consumer-grade cameras can provide useful signals for remote heart rate measurements. In this paper a simple and robust method of measuring the heart rate using low-cost webcam is proposed. Blood volume pulse is extracted by proper Region of Interest (ROI) and color channel selection from image sequences of human faces without complex computation. Heart rate is subsequently quantified by spectrum analysis. The method is successfully applied under natural lighting conditions. Results of experiments show that it takes less time, is much simpler, and has similar accuracy to the previously published and widely used method of Independent Component Analysis (ICA). Benefitting from non-contact, convenience, and low-costs, it provides great promise for popularization of home healthcare and can further be applied to biomedical research.

  11. Robust sensor fusion of unobtrusively measured heart rate.

    PubMed

    Wartzek, Tobias; Brüser, Christoph; Walter, Marian; Leonhardt, Steffen

    2014-03-01

    Contactless vital sign measurement technologies often have the drawback of severe motion artifacts and periods in which no signal is available. However, using several identical or physically different sensors, redundancy can be used to decrease the error in noncontact heart rate estimation, while increasing the time period during which reliable data are available. In this paper, we show for the first time two major results in case of contactless heart rate measurements deduced from a capacitive ECG and optical pulse signals. First, an artifact detection is an essential preprocessing step to allow a reliable fusion. Second, the robust but computationally efficient median already provides good results; however, using a Bayesian approach, and a short time estimation of the variance, best results in terms of difference to reference heart rate and temporal coverage can be achieved. In this paper, six sensor signals were used and coverage increased from 0-90% to 80-94%, while the difference between the estimated heart rate and the gold standard was less than ±2 BPM. PMID:24608065

  12. Effect of Selective Heart Rate Slowing in Heart Failure With Preserved Ejection Fraction

    PubMed Central

    Pal, Nikhil; Sivaswamy, Nadiya; Mahmod, Masliza; Yavari, Arash; Rudd, Amelia; Singh, Satnam; Dawson, Dana K.; Francis, Jane M.; Dwight, Jeremy S.; Watkins, Hugh; Neubauer, Stefan; Frenneaux, Michael

    2015-01-01

    Background— Heart failure with preserved ejection fraction (HFpEF) is associated with significant morbidity and mortality but is currently refractory to therapy. Despite limited evidence, heart rate reduction has been advocated, on the basis of physiological considerations, as a therapeutic strategy in HFpEF. We tested the hypothesis that heart rate reduction improves exercise capacity in HFpEF. Methods and Results— We conducted a randomized, crossover study comparing selective heart rate reduction with the If blocker ivabradine at 7.5 mg twice daily versus placebo for 2 weeks each in 22 symptomatic patients with HFpEF who had objective evidence of exercise limitation (peak oxygen consumption at maximal exercise [o2 peak] <80% predicted for age and sex). The result was compared with 22 similarly treated matched asymptomatic hypertensive volunteers. The primary end point was the change in o2 peak. Secondary outcomes included tissue Doppler–derived E/e′ at echocardiography, plasma brain natriuretic peptide, and quality-of-life scores. Ivabradine significantly reduced peak heart rate compared with placebo in the HFpEF (107 versus 129 bpm; P<0.0001) and hypertensive (127 versus 145 bpm; P=0.003) cohorts. Ivabradine compared with placebo significantly worsened the change in o2 peak in the HFpEF cohort (-2.1 versus 0.9 mL·kg−1·min−1; P=0.003) and significantly reduced submaximal exercise capacity, as determined by the oxygen uptake efficiency slope. No significant effects on the secondary end points were discernable. Conclusion— Our observations bring into question the value of heart rate reduction with ivabradine for improving symptoms in a HFpEF population characterized by exercise limitation. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT02354573. PMID:26338956

  13. The effect of orthostatic stress on multiscale entropy of heart rate and blood pressure.

    PubMed

    Turianikova, Zuzana; Javorka, Kamil; Baumert, Mathias; Calkovska, Andrea; Javorka, Michal

    2011-09-01

    Cardiovascular control acts over multiple time scales, which introduces a significant amount of complexity to heart rate and blood pressure time series. Multiscale entropy (MSE) analysis has been developed to quantify the complexity of a time series over multiple time scales. In previous studies, MSE analyses identified impaired cardiovascular control and increased cardiovascular risk in various pathological conditions. Despite the increasing acceptance of the MSE technique in clinical research, information underpinning the involvement of the autonomic nervous system in the MSE of heart rate and blood pressure is lacking. The objective of this study is to investigate the effect of orthostatic challenge on the MSE of heart rate and blood pressure variability (HRV, BPV) and the correlation between MSE (complexity measures) and traditional linear (time and frequency domain) measures. MSE analysis of HRV and BPV was performed in 28 healthy young subjects on 1000 consecutive heart beats in the supine and standing positions. Sample entropy values were assessed on scales of 1-10. We found that MSE of heart rate and blood pressure signals is sensitive to changes in autonomic balance caused by postural change from the supine to the standing position. The effect of orthostatic challenge on heart rate and blood pressure complexity depended on the time scale under investigation. Entropy values did not correlate with the mean values of heart rate and blood pressure and showed only weak correlations with linear HRV and BPV measures. In conclusion, the MSE analysis of heart rate and blood pressure provides a sensitive tool to detect changes in autonomic balance as induced by postural change. PMID:21799239

  14. Heart rate never lies: interventional cardiologist and Braude's quote revised

    PubMed Central

    Cook, Stéphane; Stauffer, Jean-Christophe; Goy, Jean-Jacques; Graf, Denis; Puricel, Serban; Frobert, Aurélien; Muller, Olivier; Togni, Mario; Arroyo, Diego

    2016-01-01

    Background Interventional cardiologists may be immune to stress, allowing them to perform complex percutaneous interventions under pressure. Objectives To assess heart rate (HR) variations as a surrogate marker of stress of interventional cardiologists during percutaneous cardiac procedures and in every-day life. Design This is a single-centre observational study including a total of six male interventional cardiologists performing coronary interventions and pacemaker implantations. Participants were asked to record their HR with the Apple Watch Device during procedures, every-day life and control activities such as outpatient consultations, sport, marital conflicts and sexual intercourse. Results Average daily HR was 88±17 bpm. During work days, HR increased significantly during procedures (90±17 bpm) compared with days outside the cathlab (87±17 bpm, p=0.02). The average HR was higher during a regular week working (88±16 bpm) compared with weekends off (84±18 bpm, p=0.002). Complex cardiac procedures were associated with higher HR up to 122 bpm. Peak HR were higher during physical exertion. Of note, participants complained of hypersexuality and mania after night shifts. Conclusions Work and especially percutaneous cardiac procedures increase HR independently of physical exertion suggesting that interventional cardiologists experience mental stress and emotions. PMID:26835145

  15. Pulse transducer with artifact signal attenuator. [heart rate sensors

    NASA Technical Reports Server (NTRS)

    Cash, W. H., Jr.; Polhemus, J. T. (Inventor)

    1980-01-01

    An artifact signal attenuator for a pulse rate sensor is described. The circuit for attenuating background noise signals is connected with a pulse rate transducer which has a light source and a detector for light reflected from blood vessels of a living body. The heart signal provided consists of a modulated dc signal voltage indicative of pulse rate. The artifact signal resulting from light reflected from the skin of the body comprises both a constant dc signal voltage and a modulated dc signal voltage. The amplitude of the artifact signal is greater and the frequency less than that of the heart signal. The signal attenuator circuit includes an operational amplifier for canceling the artifact signal from the output signal of the transducer and has the capability of meeting packaging requirements for wrist-watch-size packages.

  16. Decreased heart rate variability in surgeons during night shifts

    PubMed Central

    Amirian, Ilda; Andersen, Lærke Toftegård; Rosenberg, Jacob; Gögenur, Ismail

    2014-01-01

    Background Heart rate variability (HRV) has been used as a measure of stress and mental strain in surgeons. Low HRV has been associated with death and increased risk of cardiac events in the general population. The aim of this study was to clarify the effect of a 17-hour night shift on surgeons’ HRV. Methods Surgeons were monitored prospectively with an ambulatory electrocardiography device for 48 consecutive hours, beginning on a precall day and continuing through an on-call (17-h shift) day. We measured HRV by frequency domain parameters. Results We included 29 surgeons in our analysis. The median pulse rate was decreased precall (median 64, interquartile range [IQR] 56–70 beats per minute [bpm]) compared with on call (median 81, IQR 70–91 bpm, p < 0.001). Increased high-frequency (HF) activity was found precall (median 199, IQR 75–365 ms2) compared with on call (median 99, IQR 48–177 ms2, p < 0.001). The low-frequency:high-frequency (LF:HF) ratio was lower precall (median 2.7, IQR 1.9–3.9) than on call (median 4.9, IQR 3.7–6.5, p < 0.001). We found no correlation between the LF:HF ratio and performance in laparoscopic simulation. Conclusion Surgeons working night shifts had a significant decrease in HRV and a significant increase in pulse rate, representing sympathetic dominance in the autonomic nervous system. Trial registration NCT01623674 (www.clinicaltrials.gov). PMID:25265102

  17. Heart Rate and Heart Rate Variability in Dairy Cows with Different Temperament and Behavioural Reactivity to Humans

    PubMed Central

    Tőzsér, János; Szenci, Ottó; Póti, Péter; Pajor, Ferenc

    2015-01-01

    From the 1990s, extensive research was started on the physiological aspects of individual traits in animals. Previous research has established two extreme (proactive and reactive) coping styles in several animal species, but the means of reactivity with the autonomic nervous system (ANS) activity has not yet been investigated in cattle. The aim of this study was the characterization of cardiac autonomic activity under different conditions in cows with different individual characteristics. For this purpose, we investigated heart rate and ANS-related heart rate variability (HRV) parameters of dairy cows (N = 282) on smaller- and larger-scale farms grouped by (1) temperament and (2) behavioural reactivity to humans (BRH). Animals with high BRH scores were defined as impulsive, while animals with low BRH scores were defined as reserved. Cardiac parameters were calculated for undisturbed lying (baseline) and for milking bouts, the latter with the presence of an unfamiliar person (stressful situation). Sympathetic tone was higher, while vagal activity was lower in temperamental cows than in calm animals during rest both on smaller- and larger-scale farms. During milking, HRV parameters were indicative of a higher sympathetic and a lower vagal activity of temperamental cows as compared to calm ones in farms of both sizes. Basal heart rate did not differ between BRH groups either on smaller- or larger-scale farms. Differences between basal ANS activity of impulsive and reserved cows reflected a higher resting vagal and lower sympathetic activity of reserved animals compared to impulsive ones both on smaller- and larger-scale farms. There was no difference either in heart rate or in HRV parameters between groups during milking neither in smaller- nor in larger-scale farms. These two groupings allowed to draw possible parallels between personality and cardiac autonomic activity during both rest and milking in dairy cows. Heart rate and HRV seem to be useful for

  18. General anesthesia suppresses normal heart rate variability in humans

    NASA Astrophysics Data System (ADS)

    Matchett, Gerald; Wood, Philip

    2014-06-01

    The human heart normally exhibits robust beat-to-beat heart rate variability (HRV). The loss of this variability is associated with pathology, including disease states such as congestive heart failure (CHF). The effect of general anesthesia on intrinsic HRV is unknown. In this prospective, observational study we enrolled 100 human subjects having elective major surgical procedures under general anesthesia. We recorded continuous heart rate data via continuous electrocardiogram before, during, and after anesthesia, and we assessed HRV of the R-R intervals. We assessed HRV using several common metrics including Detrended Fluctuation Analysis (DFA), Multifractal Analysis, and Multiscale Entropy Analysis. Each of these analyses was done in each of the four clinical phases for each study subject over the course of 24 h: Before anesthesia, during anesthesia, early recovery, and late recovery. On average, we observed a loss of variability on the aforementioned metrics that appeared to correspond to the state of general anesthesia. Following the conclusion of anesthesia, most study subjects appeared to regain their normal HRV, although this did not occur immediately. The resumption of normal HRV was especially delayed on DFA. Qualitatively, the reduction in HRV under anesthesia appears similar to the reduction in HRV observed in CHF. These observations will need to be validated in future studies, and the broader clinical implications of these observations, if any, are unknown.

  19. Heart Rate Changes in Electroacupuncture Treated Polycystic Ovary in Rats

    PubMed Central

    Ramadoss, Mukilan; Subbiah, Angelie Jessica; Natrajan, Chidambaranathan

    2016-01-01

    Introduction Polycystic Ovary Syndrome (PCOS) is a common metabolic disorder, it affects both humans and animals. It may induce coronary heart disease, obesity and hyperandrogenism. Previous studies show that Low frequency Electroacupuncture (EA) have an effect on PCOS, however the exact pathway is unclear. Aim To find the effect of EA on autonomic activity of the heart in Estradiol Valerate (EV) induced PCOS rats. Materials and Methods Heart rate variability (HRV) was assessed in 3 groups: 1) Control; 2) PCOS rats; and 3) PCOS rats after EA treatment (n=8 in each group). From the time domain analysis and frequency domain analysis (linear measures) HRV analysis was done. EA stimulation was given at low frequency of 2Hz for 15 min on alternate days for 4-5 weeks. Collected data were statistically analysed using One-Way Analysis of Variance with the application of multiple comparisons of Tukey test. Results EA treatment group shows significant reduction in Heart Rate (HR) and low frequency, high frequency ratio (LF/HF); and increase in RR interval, Total Power (TP) when compared to PCOS group. Conclusion The study concludes that EA treatment has a significant effect on reducing sympathetic tone and decreasing HR in PCOS. PMID:27134868

  20. Gender differences in personality and heart-rate variability.

    PubMed

    Huang, Wei-Lieh; Chang, Li-Ren; Kuo, Terry B J; Lin, Yu-Hsuan; Chen, Ying-Zai; Yang, Cheryl C H

    2013-10-30

    Both personality traits and autonomic functioning show as gender differences, but their relationship is not well understood. Medically unexplained symptoms are related to personality features and can be assessed by autonomic measurement. The patterns are hypothesised to identify gender differences. We recruited 30 male and 30 female healthy volunteers. All participants completed the Tridimensional Personality Questionnaire (TPQ) and heart-rate variability (HRV) measurement. Correlation analysis was performed to identify the relationships between TPQ scores and HRV parameters. For the subjects as a whole, the subdimension harm avoidance 4 (HA4, fatigability and asthenia) was found to be negatively correlated with low-frequency (LF) power, high-frequency (HF) power and total power (TP) of HRV. Novelty seeking 1 (NS1, exploratory excitability) was found to be positively correlated with LF power and TP. Multiple linear regression analysis revealed that the interactions exploratory excitability x gender and fatigability x gender are predictors of LF and HF power, respectively. Our result supports the hypothesis that personality features such as exploratory excitability and fatigability are associated with autonomic functioning and that gender is a moderator in these relationships. PMID:23499230

  1. Extraction of heart rate variability from smartphone photoplethysmograms.

    PubMed

    Peng, Rong-Chao; Zhou, Xiao-Lin; Lin, Wan-Hua; Zhang, Yuan-Ting

    2015-01-01

    Heart rate variability (HRV) is a useful clinical tool for autonomic function assessment and cardiovascular diseases diagnosis. It is traditionally calculated from a dedicated medical electrocardiograph (ECG). In this paper, we demonstrate that HRV can also be extracted from photoplethysmograms (PPG) obtained by the camera of a smartphone. Sixteen HRV parameters, including time-domain, frequency-domain, and nonlinear parameters, were calculated from PPG captured by a smartphone for 30 healthy subjects and were compared with those derived from ECG. The statistical results showed that 14 parameters (AVNN, SDNN, CV, RMSSD, SDSD, TP, VLF, LF, HF, LF/HF, nLF, nHF, SD1, and SD2) from PPG were highly correlated (r > 0.7, P < 0.001) with those from ECG, and 7 parameters (AVNN, TP, VLF, LF, HF, nLF, and nHF) from PPG were in good agreement with those from ECG within the acceptable limits. In addition, five different algorithms to detect the characteristic points of PPG wave were also investigated: peak point (PP), valley point (VP), maximum first derivative (M1D), maximum second derivative (M2D), and tangent intersection (TI). The results showed that M2D and TI algorithms had the best performance. These results suggest that the smartphone might be used for HRV measurement. PMID:25685174

  2. Sleep apnea detection using time-delayed heart rate variability.

    PubMed

    Nano, Marina-Marinela; Xi Long; Werth, Jan; Aarts, Ronald M; Heusdens, Richard

    2015-08-01

    Sleep apnea is a sleep disorder distinguished by repetitive absence of breathing. Compared with the traditional expensive and cumbersome methods, sleep apnea diagnosis or screening with physiological information that can be easily acquired is needed. This paper describes algorithms using heart rate variability (HRV) to automatically detect sleep apneas as long as it can be easily acquired with unobtrusive sensors. Because the changes in cardiac activity are usually hysteretic than the presence of apneas with a few minutes, we propose to use the delayed HRV features to identify the episodes with sleep apneic events. This is expected to help improve the apnea detection performance. Experiments were conducted with a data set of 23 sleep apnea patients using support vector machine (SVM) classifiers and cross validations. Results show that using eleven HRV features with a time delay of 1.5 minutes rather than the features without time delay for SA detection, the overall accuracy increased from 74.9% to 76.2% and the Cohen's Kappa coefficient increased from 0.49 to 0.52. Further, an accuracy of 94.5% and a Kappa of 0.89 were achieved when applying subject-specific classifiers. PMID:26738071

  3. Extraction of Heart Rate Variability from Smartphone Photoplethysmograms

    PubMed Central

    Peng, Rong-Chao; Zhou, Xiao-Lin; Lin, Wan-Hua; Zhang, Yuan-Ting

    2015-01-01

    Heart rate variability (HRV) is a useful clinical tool for autonomic function assessment and cardiovascular diseases diagnosis. It is traditionally calculated from a dedicated medical electrocardiograph (ECG). In this paper, we demonstrate that HRV can also be extracted from photoplethysmograms (PPG) obtained by the camera of a smartphone. Sixteen HRV parameters, including time-domain, frequency-domain, and nonlinear parameters, were calculated from PPG captured by a smartphone for 30 healthy subjects and were compared with those derived from ECG. The statistical results showed that 14 parameters (AVNN, SDNN, CV, RMSSD, SDSD, TP, VLF, LF, HF, LF/HF, nLF, nHF, SD1, and SD2) from PPG were highly correlated (r > 0.7, P < 0.001) with those from ECG, and 7 parameters (AVNN, TP, VLF, LF, HF, nLF, and nHF) from PPG were in good agreement with those from ECG within the acceptable limits. In addition, five different algorithms to detect the characteristic points of PPG wave were also investigated: peak point (PP), valley point (VP), maximum first derivative (M1D), maximum second derivative (M2D), and tangent intersection (TI). The results showed that M2D and TI algorithms had the best performance. These results suggest that the smartphone might be used for HRV measurement. PMID:25685174

  4. Improving Interprofessional Consistency in Electronic Fetal Heart Rate Interpretation.

    PubMed

    Govindappagari, Shravya; Zaghi, Sahar; Zannat, Ferdous; Reimers, Laura; Goffman, Dena; Kassel, Irene; Bernstein, Peter S

    2016-07-01

    Objective To determine if mandatory online training in electronic fetal monitoring (EFM) improved agreement in documentation between obstetric care providers and nurses on labor and delivery. Methods Health care professionals working in obstetrics at our institution were required to complete a course on EFM interpretation. We performed a retrospective chart review of 701 charts including patients delivered before and after the introduction of the course to evaluate agreement among providers in their documentation of their interpretations of the EFM tracings. Results Agreement between provider and nurse documentation at the time of admission improved for variability and accelerations (variability: 91.1 vs. 98.3%, p < 0.001; and accelerations: 75.2 vs. 87.7%, p < 0.001). Similarly, agreement improved at the time of the last note prior to delivery for documentation of variability and accelerations (variability: 82.1 vs. 90.6%, p = 0.001; and accelerations: 56.7 vs. 68.6%, p = 0.0012). Agreement in interpretation of decelerations both at the time of admission and at the time of delivery increased (86.3 vs. 90.6%, p = 0.0787, and 56.7 vs. 61.1%, p = 0.2314, respectively) but was not significant. Conclusion An online EFM course can significantly improve consistency in multidisciplinary documentation of fetal heart rate tracing interpretation. PMID:26906180

  5. The role of heart rate variability in sports physiology

    PubMed Central

    DONG, JIN-GUO

    2016-01-01

    Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology. PMID:27168768

  6. Post-Exercise Heart Rate Recovery Independently Predicts Mortality Risk in Patients with Chronic Heart Failure

    PubMed Central

    Tang, Yi-Da; Dewland, Thomas A.; Wencker, Detlef; Katz, Stuart D.

    2009-01-01

    Background Post-exercise heart rate recovery (HRR) is an index of parasympathetic function associated with clinical outcomes in populations with and without documented coronary heart disease. Decreased parasympathetic activity is thought to be associated with disease progression in chronic heart failure (HF), but an independent association between post-exercise HRR and clinical outcomes among such patients has not been established. Methods and Results We measured HRR (calculated as the difference between heart rate at peak exercise and after 1 minute of recovery) in 202 HF subjects and recorded 17 mortality and 15 urgent transplantation outcome events over 624 days of follow-up. Reduced post-exercise HRR was independently associated with increased event risk after adjusting for other exercise-derived variables (peak oxygen uptake and VE/VCO2 slope), for the Heart Failure Survival Score (adjusted HR 1.09 for one beat/min reduction, 95% CI 1.05-1.13, p<0.0001) and the Seattle Heart Failure Model score (adjusted HR 1.08 for one beat/min reduction, 95% CI 1.05-1.12, p<0.0001). Subjects in the lowest risk tertile based on post-exercise HRR (≥30 beats/min) had low risk of events irrespective of the risk predicted by the survival scores. In a subgroup of 15 subjects, reduced post-exercise HRR was associated with increased serum markers of inflammation (interleukin-6 r=0.58, p=0.024, high sensitivity C-reactive protein r=0.66, p=0.007). Conclusions Post-exercise HRR predicts mortality risk in patients with HF and provides prognostic information independent of previously described survival models. Pathophysiologic links between autonomic function and inflammation may be mediators of this association. PMID:19944361

  7. Spectral photoplethysmographic imaging sensor fusion for enhanced heart rate detection

    NASA Astrophysics Data System (ADS)

    Amelard, Robert; Clausi, David A.; Wong, Alexander

    2016-03-01

    Continuous heart rate monitoring can provide important context for quantitative clinical assessment in scenarios such as long-term health monitoring and disability prevention. Photoplethysmographic imaging (PPGI) systems are particularly useful for such monitoring scenarios as contact-based devices pose problems related to comfort and mobility. Each pixel can be regarded as a virtual PPG sensor, thus enabling simultaneous measurements of multiple skin sites. Existing PPGI systems analyze temporal PPGI sensor uctuations related to hemodynamic pulsations across a region of interest to extract the blood pulse signal. However, due to spatially varying optical properties of the skin, the blood pulse signal may not be consistent across all PPGI sensors, leading to inaccurate heart rate monitoring. To increase the hemodynamic signal-to-noise ratio (SNR), we propose a novel spectral PPGI sensor fusion method for enhanced estimation of the true blood pulse signal. Motivated by the observation that PPGI sensors with high hemodynamic SNR exhibit a spectral energy peak at the heart rate frequency, an entropy-based fusion model was formulated to combine PPGI sensors based on the sensors' spectral energy distribution. The optical PPGI device comprised a near infrared (NIR) sensitive camera and an 850 nm LED. Spatially uniform irradiance was achieved by placing optical elements along the LED beam, providing consistent illumination across the skin area. Dual-mode temporally coded illumination was used to negate the temporal effect of ambient illumination. Experimental results show that the spectrally weighted PPGI method can accurately and consistently extract heart rate information where traditional region-based averaging fails.

  8. Dynamics of myocardial lactate efflux after a step in heart rate in isolated rabbit hearts.

    PubMed

    Hak, J B; van Beek, J H; van Wijhe, M H; Westerhof, N

    1993-12-01

    We investigated whether a glycolytic burst contributes to the initial adaptation of ATP synthesis to increased cardiac metabolic demand. Six isolated rabbit hearts were perfused with glucose-containing Tyrode solution at 28 degrees C. In venous and arterial samples the lactate concentration was determined with a sensitive enzymatic cycling method. After the heart rate was doubled from 60 to 120 beats/min, lactate efflux increased from 0.23 +/- 0.10 (SE) to 0.45 +/- 0.12 mumol.min-1.g-1 dry weight with a mean response time of 21.3 s but without an overshoot. The transport time for lactate is longer than 15.7 s, suggesting that lactate production adapts with a mean response time of less than 6 s. Because no overshoot in lactate efflux was found, it is unlikely that a glycolytic burst after a step in heart rate contributes to the fast adaptation of ATP synthesis to demand in the isolated rabbit heart, although it might be possible that a change in cytosolic lactate production is not reflected in an increase in lactate efflux. Extrapolation of the results of this study to the in vivo situation should be done with caution. PMID:8285247

  9. Photoplethysmographic imaging via spectrally demultiplexed erythema fluctuation analysis for remote heart rate monitoring

    NASA Astrophysics Data System (ADS)

    Deglint, Jason; Chung, Audrey G.; Chwyl, Brendan; Amelard, Robert; Kazemzadeh, Farnoud; Wang, Xiao Yu; Clausi, David A.; Wong, Alexander

    2016-03-01

    Traditional photoplethysmographic imaging (PPGI) systems use the red, green, and blue (RGB) broadband measurements of a consumer digital camera to remotely estimate a patients heart rate; however, these broadband RGB signals are often corrupted by ambient noise, making the extraction of subtle fluctuations indicative of heart rate difficult. Therefore, the use of narrow-band spectral measurements can significantly improve the accuracy. We propose a novel digital spectral demultiplexing (DSD) method to infer narrow-band spectral information from acquired broadband RGB measurements in order to estimate heart rate via the computation of motion- compensated skin erythema fluctuation. Using high-resolution video recordings of human participants, multiple measurement locations are automatically identified on the cheeks of an individual, and motion-compensated broadband reflectance measurements are acquired at each measurement location over time via measurement location tracking. The motion-compensated broadband reflectance measurements are spectrally demultiplexed using a non-linear inverse model based on the spectral sensitivity of the camera's detector. A PPG signal is then computed from the demultiplexed narrow-band spectral information via skin erythema fluctuation analysis, with improved signal-to-noise ratio allowing for reliable remote heart rate measurements. To assess the effectiveness of the proposed system, a set of experiments involving human motion in a front-facing position were performed under ambient lighting conditions. Experimental results indicate that the proposed system achieves robust and accurate heart rate measurements and can provide additional information about the participant beyond the capabilities of traditional PPGI methods.

  10. Analysis of long term heart rate variability: methods, 1/f scaling and implications

    NASA Technical Reports Server (NTRS)

    Saul, J. P.; Albrecht, P.; Berger, R. D.; Cohen, R. J.

    1988-01-01

    The use of spectral techniques to quantify short term heart rate fluctuations on the order of seconds to minutes has helped define the autonomic contributions to beat-to-beat control of heart rate. We used similar techniques to quantify the entire spectrum (0.00003-1.0 Hz) of heart rate variability during 24 hour ambulatory ECG monitoring. The ECG from standard Holter monitor recordings from normal subjects was sampled with the use of a phase locked loop, and a heart rate time series was constructed at 3 Hz. Frequency analysis of the heart rate signal was performed after a nonlinear filtering algorithm was used to eliminate artifacts. A power spectrum of the entire 24 hour record revealed power that was inversely proportional to frequency, 1/f, over 4 decades from 0.00003 to 0.1 Hz (period approximately 10 hours to 10 seconds). Displaying consecutive spectra calculated at 5 minute intervals revealed marked variability in the peaks at all frequencies throughout the 24 hours, probably accounting for the lack of distinct peaks in the spectra of the entire records.