Sampling period determination for heart rate logging under an exercise regimen

Using a mathematical procedure, we determine appropriate sampling rates for logging heart rate, at a variety of exercise intensities. The mathematical procedure involves correlating exercise and heart rate data to determine a dynamical mathematical model, from which the frequency response of the relationship between exercise intensity and heart rate can be determined. The sampling rate is then straightforwardly deduced by making appropriate measurements on the frequency response curve. We show how careful consideration needs to be given to the choice of dynamical model structure and the work regimen, so that consistent and convincing conclusions can be drawn. We demonstrate that the dynamics of the work-rate/heart-rate system are dependent on the nominal work/heart rate, but a 5-s sampling period, as used in many commercial heart rate monitors, appears to be adequate, especially when some averaging is performed before logging.     

Thermoneutral immersion exercise accelerates heart rate recovery: A potential novel training modality

This study compared heart rate recovery (HRR) after incremental maximal exercise performed at the same external power output (P_ext) on dry land ergocycle (DE) vs. immersible ergocycle (IE). Fifteen young healthy participants (30?±?7 years, 13 men and 2 women) performed incremental maximal exercise tests on DE and on IE. The initial P_ext on DE was 25?W and was increased by 25?W/min at a pedalling cadence between 60 and 80?rpm, while during IE immersion at chest level in thermoneutral water (30°C), the initial P_ext deployment was at a cadence of 40?rpm which was increased by 10?rpm until 70?rpm and thereafter by 5?rpm until exhaustion. Gas exchange and heart rate (HR) were measured continuously during exercise and recovery for 5?min. Maximal HR (DE: 176?±?15 vs. IE 169?±?12?bpm) reached by the subjects in the two conditions did not differ (P?>?.05). Parasympathetic reactivation parameters (ΔHR from 10 to 300?s) were compared during the DE and IE HR recovery recordings. During the IE recovery, parasympathetic reactivation in the early phase was more predominant (HRR at Δ10–Δ60?s, P?<?.05), but similar in the late phase (HRR at Δ120–Δ300?s, P?>?.05) when compared to the DE condition. In conclusion, incremental maximal IE exercise at chest level immersion in thermoneutral water accelerates the early phase parasympathetic reactivation compared to DE in healthy young participants.     

Methods and impact of correcting heart rate data errors during exercise in older adults

Heart rate (HR) by time curves could be useful as a measure of treatment fidelity (TF). The purposes were to describe the frequency of common recording irregularities (e.g. errors) observed during exercise, validate a process to correct those errors, and determine whether there is a clinically meaningful benefit to data correction. In total, 1895 exercise sessions from 69 older adults with hip fracture were inspected for errors in the placement of event markers (duration of exercise) and signal artifacts. Marker errors occurred in 33% of the participants and corrected in 324 sessions. Signal artifacts occurred in 96% of the participants and eliminated in 702 sessions. Computer code was 85% accurate in detecting signal artifacts, compared to 97% for investigators. HR was significantly higher after correction, but the average change was only 0.69 + 1.20 beats per minute. An HR monitor showing HR by time curves (HRxTC) can be used to evaluate TF during exercise.     

Intra-day and inter-day reliability of heart rate variability measurement

Abstract

At present, analysis of heart rate variability (HRV) is becoming widely used as a clinical or research tool. Supported reliability studies for HRV measurement are, however, still limited. The main purpose was to perform an assessment of the absolute and relative reliability of HRV parameters from short-term recordings by means of orthoclinostatic stimulation and to investigate, whether there is a difference in repeating the retest immediately or after several days. The study group consisted of 99 participants (mean age 22 ± 1.24 years). Standard HRV indexes were computed: PT (total spectral power), PHF (high frequency spectral power), PLF (low frequency spectral power) and LF/HF. Absolute reliability was assessed by the standard error of measurement and 95% limits of agreement; relative reliability was assessed by the intraclass correlation coefficient. There was also an estimate of the sample size needed to detect the mean difference ≥ 30% of the between-subject standard deviation. In conclusion, a large random variation (within individuals) of HRV parameters was revealed, regardless of whether the retest was repeated immediately or with an interruption. For most HRV parameters (particularly in the immediately repeated test-retest), however, random variation represents a limited portion of the between-subject variability.     

Accuracy of an infrared LED device to measure heart rate and energy expenditure during rest and exercise

Abstract

The purpose of this study was to examine the accuracy of the ePulse Personal Fitness Assistant, a forearm-worn device that provides measures of heart rate and estimates energy expenditure. Forty-six participants engaged in 4-minute periods of standing, 2.0 mph walking, 3.5 mph walking, 4.5 mph jogging, and 6.0 mph running. Heart rate and energy expenditure were simultaneously recorded at 60-second intervals using the ePulse, an electrocardiogram (EKG), and indirect calorimetry. The heart rates obtained from the ePulse were highly correlated (intraclass correlation coefficients [ICCs] ≥0.85) with those from the EKG during all conditions. The typical errors progressively increased with increasing exercise intensity but were <5 bpm only during rest and 2.0 mph. Energy expenditure from the ePulse was poorly correlated with indirect calorimetry (ICCs: 0.01–0.36) and the typical errors for energy expenditure ranged from 0.69–2.97 kcal · min^?1, progressively increasing with exercise intensity. These data suggest that the ePulse Personal Fitness Assistant is a valid device for monitoring heart rate at rest and low-intensity exercise, but becomes less accurate as exercise intensity increases. However, it does not appear to be a valid device to estimate energy expenditure during exercise.     

Autonomic modulation of heart rate in paraplegic wheelchair basketball players: Linear and nonlinear analysis

Abstract

This study aimed to evaluate the autonomic modulation of heart rate in sedentary paraplegics and paraplegic wheelchair basketball players with thoracic spinal cord injury below T6. Seven paraplegic wheelchair basketball players (active paraplegic group), five paraplegics who were not involved in regular exercise (sedentary paraplegic group) and 10 able-bodied participants (control group) took part in the study. The heart rate variability was evaluated by linear (low frequency and high frequency band in normalised units and low frequency/high frequency ratio) and nonlinear methods (Shannon entropy, corrected conditional entropy, and symbolic analysis).

The sedentary group presented significantly higher values for low frequency, low frequency/high frequency ratio and symbolic index with no significant variations (0V%), and also lower values for the high frequency and symbolic index with two significant unlike variation (2ULV%) compared to active paraplegic group. Shannon entropy and corrected conditional entropy analyses revealed significantly lower values in the sedentary group than in the control or active paraplegic groups. Paraplegic individuals who regularly undertake physical exercise have higher complexity of R-R interval time series, lower sympathetic modulation, and higher parasympathetic modulation than sedentary paraplegic participants.     

Maximal heart rate declines linearly with age independent of cardiorespiratory fitness levels

There have been many conflicting observations between the linear or curvilinear decline in maximal heart rate (HR_max) with age. The aim of this study was to determine if linear or curvilinear equations would better describe the decline in HR_max with age in individuals of differing cardiorespiratory fitness (CRF) levels. Treadmill cardiopulmonary exercise test (CPX) results from participants (1510 men and 1134 women; 18–76 years) free of overt cardiovascular disease were retrospectively examined using cross-sectional and longitudinal study designs. Participants completing ≥2 CPX with ≥1 year between test dates were included in the longitudinal analysis (325 men and 150 women). Linear and quadratic regressions were applied to age and HR_max for the whole cohort and respective CRF groups (high, moderate, and low, relative to age and gender normative values). To test for differences among linear, quadratic, and polynomial equations, the change in R² (cross-sectional analysis) and Bayesian information criterion (BIC) (longitudinal analysis) from the linear to the more complex models were calculated. The quadratic or polynomial regression in the cross-sectional analysis, marginally improved the variance in HR_max explained by age compared to the linear regression for the whole cohort (0.2%), moderate fit group (0.3%), and low fit group (0.8%). With no improvements in the high fit group. BIC did not improve for any CRF category in the longitudinal analysis. In conclusion, the minimal differences among linear, quadratic, and polynomial equations in the respective CRF groups, emphasizes the use of linear prediction equations to estimate HR_max.     

Effects of total sleep deprivation on endurance cycling performance and heart rate indices used for monitoring athlete readiness

ABSTRACT

This study investigated effects of total sleep deprivation on self-paced endurance performance, and heart rate (HR) indices of athletes' “readiness to perform”. Endurance athletes (n = 13) completed a crossover experiment comprising a normal sleep (NS) and sleep deprivation (SD) condition. Each required completion of an endurance time-trial (TT) on consecutive days (D1, D2) separated by normal sleep or total sleep deprivation. Finishing time, perceived exertion (RPE), mood, psychomotor vigilance (PVT), and HR responses were assessed. Time on D2 of SD was 10% slower than D2 of NS (64 ± 7 vs 59 ± 4 min, P < 0.01), and 11% slower than D1 of SD (58 ± 5 min, P < 0.01). Subjective to objective (RPE:mean HR) intensity ratio was higher on D2 of SD compared with D2 of NS and D1 of SD (P < 0.01). Mood disturbance and PVT mean response time increased on D2 of SD compared with D2 of NS and D1 of SD. Anaerobic threshold and change in TT time were correlated (R = ?0.73, P < 0.01). Sleep helps to optimise endurance performance. Subjective to objective intensity ratios appear sensitive to effects of sleep on athletes’ readiness. Research examining more subtle sleep manipulation is required.     

不同高度的手臂运动与心率变化的研究

目的：通过小样本实验研究,对运动中手臂高度与心率变化的机制进行探析。方法：监测15名受试者在运动中两臂直臂侧上摆和侧下摆的心率变化;两臂侧上屈伸和侧下屈伸的心率变化。结果：运动中手臂高度超过心脏能够促使心跳加速。结论：运动中手臂高度超过心脏能够促使心跳加速主要与重力势能、动力肌肉群做功、运动强度和心脏供血量等参数的变化有关。     

利用团队心率对优秀中长跑运动员高强度间歇跑的监控研究

通过团队心率追踪运动员在间歇训练中的心率变化,并对其进行对比分析,找出运动员在训练中的心率特点,旨在为今后的训练提供参考。     

Effect of asthma and six-months high-intensity interval training on heart rate variability during exercise in adolescents

ABSTRACT

Little is known regarding the influence of asthma and exercise, and their interaction, on heart rate variability (HRV) in adolescents.

Thirty-one adolescents with asthma (13.7±0.9 years; 21.9±3.9 kg·m^?2; 19 boys, 12 girls) and thirty-three healthy adolescents (13.8±0.9 years; 20.3±3.2 kg·m^?2; 16 boys, 17 girls) completed an incremental ramp test and three heavy-intensity constant-work-rate cycle tests. Thirteen adolescents (7 boys, 6 girls; 6 asthma, 7 control) completed six-months high-intensity interval training (HIIT) and were compared to age- and sex-matched controls. Standard time-domain, frequency-domain and non-linear indices of HRV were derived at baseline, three- and six-months.

Asthma did not influence HRV at baseline or following HIIT. Total power, low frequency and normalised low frequency power, and sympathovagal balance increased at three-months in HIIT, subsequently declining towards baseline at six-months. Normalised high frequency power was reduced at three-months in both groups, which was sustained at six-months. No effects of HIIT were observed in the time-domain nor in the non-linear indices.

HRV was not influenced by asthma, potentially because such derangements are a function of disease progression, severity or duration. HIIT may be associated with a short-term shift towards greater sympathetic predominance during exercise, perhaps caused by physiological overload and fatigue.     

业余男子中长跑运动员心率和血乳酸峰值与高水平运动员的对比研究

以福建师大和福建医科大学的10位男子长跑队员为研究对象,采用试验方法和先进的仪器,分别对业余运动员与高水平运动后不同时间内的血乳水平,以及他们运动后第4min心率进行比较,准确监测运动员的技能状态和训练水平,从而科学的制定训练计划,科学指导训练。     

有氧健身操对增强中年女性心肺功能的作用

通过对80名中年女性实施12周有氧健身操练习，探讨有氧健身操对提高中年女性心肺功能的作用，结果发现有氧健身操可降低安静心率与血压，提高台阶实验指数，增加肺活量，是一种有效提高中年女性心肺功能的健身方法。     

遥测心率及其软件的设计及功能

遥测心率及其软件设计是在目前微型计算机普遍使用Windows操作系统平台上建立起来的。可实现运用计算机自动采集心率，分析处理以及运动负荷的自动评估，提高分析评估体育课学生运动负荷的效率。     

Exercise-induced hypoalgesia: Pain tolerance,preference and tolerance for exercise intensity,and physiological correlates following dynamic circuit resistance exercise

Previous research has demonstrated significant decreases in pain perception in healthy individuals following both aerobic and upper body resistance exercise, but research on circuit training has been limited. The purpose of the study was to determine the effects of a strenuous bout of dynamic circuit resistance exercise on pain threshold and pain tolerance in conjunction with changes in blood lactate levels, heart rate (HR), and perceived exertion. A sample of 24 college-age students participated in 2 sessions: (1) a maximal strength testing session and (2) a circuit training bout of exercise that consisted of 3 sets of 12 repetitions with a 1:1 work to rest ratio at 60% one-repetition maximum (1-RM) predicted from a three-repetition maximum (3-RM) for 9 exercises. Participants exhibited increases in pain tolerance, blood lactate levels, HR and perceived exertion following resistance exercise. Preference for exercise intensity was positively correlated with lactate post exercise and tolerance for exercise intensity was positively correlated with pain tolerance and lactate post exercise. In conclusion, this is the first study to demonstrate increases in pain tolerance following a dynamic circuit resistance exercise protocol and disposition for exercise intensity may influence lactate and pain responses to circuit resistance exercise.     

Effect of individualized resistance training prescription with heart rate variability on individual muscle hypertrophy and strength responses

Abstract

The aim of the present study was to investigate if resistance training (RT), performed with individualized recovery between sessions (RT-IND), promotes greater gains in strength and muscle mass and reduces the variability on adaptations compared to RT with fixed recovery intervals (RT-FIX). Twenty young men (age 21.9?±?3.3 years) were randomized in the RT-IND and RT-FIX groups. Five days before the beginning of the training, measurements of the root mean square of successive R-R intervals differences (RMSSD) values of each individual were performed to establish the baseline values. Before each RT session, the RMSSD values determined whether the participants from RT-IND protocol were recovered from the previous session. Participants performed the RT session only if RMSSD values had returned to the baseline, otherwise they had to wait for an additional 24?h. RT-FIX performed an RT session every 48?h. Muscle strength was measured by one-maximal repetition (1-RM) test and muscle cross-section area (CSA) of the vastus laterals by ultrasonography were assessed pre- and post-training. 1-RM values increased significantly from pre to post-training for both groups (RT-IND: 30% and RT-FIX: 42%, main time effect, P?<?0001), with no significant difference between groups. Muscle CSA increased significantly from pre to post-training (RT-IND: 15.7% and RT-FIX: 15.8%, main time effect, P?<?0001), with no significant difference between groups. In conclusion, RT-IND did not increase the gains in muscle strength and mass neither reduce the variability in muscle adaptations when compared to the RT-FIX.     

足球运动员高原及平原长距离匀速耐力跑时心率漂移现象的观察与分析

研究目的是观察平原及高原匀速耐力跑时足球运动员心车漂移现象及不同运动能力的运动员之间心率漂移的差异，分析不同耐力水平运动员心率漂移的变化对运动能力的影响。研究结果表明足球运动员平原及高原匀速耐力跑时无论是在平原还是在高原所有受试者都不同程度地出现心率漂移现象。但高原各心半指标均高于平原。不同运动能力受试者所存在妁心率漂移现象差异在一定程度上反映了最大摄氧能力差异。但心率漂移现象作为评定呼吸和循环系统机能妁指杯还需有更多妁其他生理指标支持。     

The effect on heart rate variability of acclimatization to a humid,hot environment after a transition across five time zones in elite junior rowers

Abstract

The aim of this study was to examine the simultaneous effect on heart rate variability (HRV) of acclimatization to a hot, humid environment and a transition of five time zones in elite junior rowers. Thirteen rowers (12 males and 1 female) participated in the study. Each rower was monitored during training camps in temperate and in humid, hot conditions before and during the Junior Rowing World Championship. All participants recorded the lengths of high-intensity training sessions, and R-R (the time between the R peaks of consecutive QRS complexes) intervals were measured every morning after awakening. Compared with baseline values taken during training before the transition to the new time zone and climate, HRV indices during first 3 days of acclimatization remained unchanged. On the fourth and fifth days of acclimatization, significant decreases in measures of heart rate variability in the standing position were observed. Beginning from the sixth day of acclimatization and for all subsequent days, the HRV indices, while standing, returned to baseline values and were not significantly different from baseline. Despite this, there were no significant changes in HRV measures in a supine position until the eighth day of acclimatization. R-R intervals decreased and mean heart rate increased significantly (P<0.001) during days 8–10 of acclimatization. In conclusion, major physiological adaptation of HRV indices in the standing position during acclimatization to a humid, hot environment, with a transition across five time zones, occurs within the first 5 days in elite athletes before returning to baseline. Indices of heart rate variability in the supine position correlate with the length of high-intensity training sessions on the previous day.