Reliability of Postexercise Heart Rate Recovery

Accuracy of Heart-Rate-Recovery Parameters Assessed From a Wrist-Worn Photoplethysmography Monitor (Polar Unite)

PURPOSE

The accuracy of heart rate (HR) measured with a wrist-worn photoplethysmography (PPG) monitor is altered during rest-exercise and exercise-rest transitions, which questions the validity of postexercise HR-recovery (HRR) parameters estimated from this device.

METHODS

Thirty participants (50% female) randomly performed two 13-minute sequences (3' rest, 5' submaximal-intensity exercise, and 5' passive recovery) on treadmill and bicycle ergometers. HR was measured concomitantly with a 10-lead electrocardiogram (ECG) and a wrist-worn PPG monitor (Polar Unite). HRR was assessed by calculating Δ60 (the difference between HR during exercise and HR 60 s after exercise cessation) and by fitting HRR data into a monoexponential model.

RESULTS

By focusing on Δ60 and τ (the time constant of the monoexponential curve), levels of association (r) of the Unite versus the 10-lead ECG were high to very high (.73 < r < .93), and coefficients of variation were >20% (in absolute value), except for Δ60 in the bicycle ergometer condition (11.7%). In 97% of cases, the decrease in HR after exercise appeared later with the Unite. By adjusting the time window used for the analysis according to this time lag, coefficients of variation of Δ60 decreased below 10% in the bicycle ergometer condition.

CONCLUSIONS

If a wrist-worn PPG monitor is used to assess HRR, we recommend performing the submaximal-intensity exercise on a bicycle ergometer and focusing on Δ60. Furthermore, to obtain a more accurate Δ60, the time lag between the end of the exercise and the effective decrease in HR should also be considered before the calculation.

Prediction of Relevant Training Control Parameters at Individual Anaerobic Threshold without Blood Lactate Measurement

BACKGROUND

Active exercise therapy plays an essential role in tackling the global burden of obesity. Optimizing recommendations in individual training therapy requires that the essential parameters heart rate HR(IAT) and work load (W/kg(IAT) at individual anaerobic threshold (IAT) are known. Performance diagnostics with blood lactate is one of the most established methods for these kinds of diagnostics, yet it is also time consuming and expensive.

METHODS

To establish a regression model which allows HR(IAT) and (W/kg(IAT) to be predicted without measuring blood lactate, a total of 1234 performance protocols with blood lactate in cycle ergometry were analyzed. Multiple linear regression analyses were performed to predict the essential parameters (HR(IAT)) (W/kg(IAT)) by using routine parameters for ergometry without blood lactate.

RESULTS

HR(IAT) can be predicted with an RMSE of 8.77 bpm (p < 0.001), R² = 0.799 (|R| = 0.798) without performing blood lactate diagnostics during cycle ergometry. In addition, it is possible to predict W/kg(IAT) with an RMSE (root mean square error) of 0.241 W/kg (p < 0.001), R² = 0.897 (|R| = 0.897).

CONCLUSIONS

It is possible to predict essential parameters for training management without measuring blood lactate. This model can easily be used in preventive medicine and results in an inexpensive yet better training management of the general population, which is essential for public health.

Validity and sensitivity of field tests' heart-rate recovery assessment in recreational football players

We aimed at examining the criterion validity and sensitivity of heart-rate recovery (HRRec) in profiling cardiorespiratory fitness in male recreational football players in the untrained and trained status, using endurance field-tests. Thirty-two male untrained subjects (age 40 ± 6 years, VO2max 41.7 ± 5.7 ml·kg-1·min-1, body mass 82.7 ± 9.8 kg, stature 173.3 ± 7.4 cm) participated in a 12-week (2‒3 sessions per week) recreational football intervention and were tested pre- and post-intervention (i.e. untrained and trained status). The participants performed three intermittent field tests for aerobic performance assessment, namely Yo-Yo intermittent endurance level 1 (YYIE1) and level 2 (YYIE2) tests, and Yo-Yo intermittent recovery level 1 (YYIR1) test. VO2max was assessed by performing a progressive maximal treadmill test (TT) and maximal HR (HRmax) determined as the maximal value across the testing conditions (i.e., Yo-Yo intermittent tests or TT). HRRec was calculated as the difference between Yo-Yo tests' HRpeak or HRmax and HR at 30 s (HR30), 60 s (HR60) and 120 s (HR120) and considered as beats·min-1 (absolute) and as % of tests' HRpeak or HRmax values. Significant post-intervention improvements (p<0.0001) were shown in VO2max (8.6%) and Yo-Yo tests performance (23-35%). Trivial to small (p>0.05) associations were found between VO2max and HRRec (r = -0.05-0.27, p>0.05) across the Yo-Yo tests, and training status either expressed as percentage of HRpeak or HRmax. The results of this study do not support the use of field-test derived HRRec to track cardiorespiratory fitness and training status in adult male recreational football players.

Heart rate recovery to assess fitness: comparison of different calculation methods in a large cross-sectional study

We propose a cross-sectional study based on 980 maximal effort tests to quantify the effect of the calculation method of heart rate recovery (HRR) on its association with cardiorespiratory fitness (CRF). For five different time t₀ after exercise cessation, HRR has been calculated as: the difference and the ratio between maximal measured heart rate and heart rate (HR) at t₀HR at t₀the decay time of an exponential decay encompassing the first t₀ minutes of the HR recovery.The associations between HRR indices and CRF were estimated from generalized estimating equations stratified by gender and adjusted for age and body mass index. For HRR indices based on exponential regression, no significant association with CRF was found, whereas the other HRR indices are associated with CRF when t₀ is at least 1 minute and is maximum for t₀ = 2 minutes for females and t₀ = 3 minutes for males.

Heart Rate Recovery (HRR) Is Not a Singular Predictor for Physical Fitness

BACKGROUND

For optimal recommendations in cardiovascular training for the general population, knowing the essential parameters for physical fitness is required. Heart rate recovery (HRR) is an easy-to-measure parameter and is discussed to derive the physical fitness of an individual subject. This study evaluates HRR as a potential physical fitness parameter for public health programs, as it is measured in every ergometry.

METHODS

In this retrospective cross-sectional study, we analyzed HRR regarding physical fitness (W/kg (IAT: individual anaerobic threshold)). In total, we analyzed 1234 performance protocols in cycle ergometry. Significance tests (p < 0.001) and multiple linear regression were performed.

RESULTS

The analysis of HRR and weight-related performance showed a significant correlation with a moderate coefficient of determination (R² = 0.250). The coefficient of determination increases from very weak correlation levels at 1 min post-workout towards weak to moderate levels of correlation at 5 min post-workout.

CONCLUSIONS

In this study HRR and the weight-related performance at the IAT showed a significant correlation with a mean strength. Thus, a prediction or conclusion on physical performance based singularly on HRR decrease is not recommended. However, in preventive medicine, HRR should be measured and observed on a long-term basis, for analysis of vagal activity and to draw to inferences of mortality.

Influence of diet on acute endocannabinoidome mediator levels post exercise in active women, a crossover randomized study

The extended endocannabinoid system, also termed endocannabinoidome, participates in multiple metabolic functions in health and disease. Physical activity can both have an acute and chronic impact on endocannabinoid mediators, as does diet. In this crossover randomized controlled study, we investigated the influence of diet on the peripheral response to acute maximal aerobic exercise in a sample of active adult women (n = 7) with no underlying metabolic conditions. We compared the impact of 7-day standardized Mediterranean diet (MedDiet) and control diet inspired by Canadian macronutrient intake (CanDiet) on endocannabinoidome and short-chain fatty acid metabolites post maximal aerobic exercise. Overall, plasmatic endocannabinoids, their congeners and some polyunsaturated fatty acids increased significantly post maximal aerobic exercise upon cessation of exercise and recovered their initial values within 1 h after exercise. Most N-acylethanolamines and polyunsaturated fatty acids increased directly after exercise when the participants had consumed the MedDiet, but not when they had consumed the CanDiet. This impact was different for monoacylglycerol endocannabinoid congeners, which in most cases reacted similarly to acute exercise while on the MedDiet or the CanDiet. Fecal microbiota was only minimally affected by the diet in this cohort. This study demonstrates that endocannabinoidome mediators respond to acute maximal aerobic exercise in a way that is dependent on the diet consumed in the week prior to exercise.

Benefits of a Supervised Ambulatory Outpatient Program in a Cardiovascular Rehabilitation Unit Prior to a Heart Transplant: A Case Study

Preoperative peak oxygen uptake (V.O2peak) and ventilatory efficiency (V.E/V.CO2slope) are related to the vital prognosis after cardiac transplantation (HTx). The objective of our study was to evaluate the effects of exercise-based cardiac rehabilitation (ECR) program on the preoperative exercise capacity of a HTx candidate. A male patient, aged 50–55 years, with chronic heart failure was placed on the HTx list and performed 12 weeks of intensive ECR (5 sessions-a-week). Our results showed that the cardiac index continuously increased between the onset and the end of ECR (1.40 vs. 2.53 L.min–1.m2). The first 20 sessions of ECR induced a V.O2peak increase (15.0 vs. 19.3 ml.min–1.kg–1, corresponding to 42.0 and 53.0% of its maximal predicted values, respectively). The peak V.O2 plateaued between the 20th and the 40th ECR session (19.3 vs. 19.4 ml.min–1.kg–1) then progressively increased until the 60th ECR session to reach 25.7 ml.min–1.kg–1, i.e., 71.0% of the maximal predicted values. The slope of V.E/V.CO2 showed a biphasic response during the ECR program, with an increase between the onset and the 20th ECR session (58.02 vs. 70.48) and a decrease between the 20th and the 40th ECR session (70.48 vs. 40.94) to reach its minimal value at the 60th ECR session (31.97). After the first 40 sessions of the ECR program, the Seattle Heart Failure Model score predicted median survival time was estimated at 7.2 years. In conclusion, the improvement in exercise capacity and cardiorespiratory function following the ECR helped delay the heart transplant surgery in our patient awaiting heart transplantation.

Heart rate-based indices to detect parasympathetic hyperactivity in functionally overreached athletes. A meta-analysis

Investigations into the sensitivity of heart rate-(HR) derived indices for tracking parasympathetic nervous system (PNS) changes in functionally overreached (F-OR) endurance-trained athletes have produced equivocal findings. Lack of clarity may be a result of methodological inconsistencies. Therefore, the aims of this systematic review and meta-analysis were (a) to determine the sensitivity of resting and post-exercise vagal-related HR variability (HRV) and HR recovery (HRR) indices to detect PNS modulation in F-OR and non-overreached (non-OR) athletes, and (b) to investigate the influence of methodological factors on the sensitivity of HR-based indices to detect PNS hyperactivity in F-OR athletes. We searched CENTRAL, Scopus, PubMed, Embase, and Web of Science up to May 2020 for the following terms: male and female endurance-trained athletes, controlled and uncontrolled studies that carried out an overload training period, and PNS modulation measured in resting and post-exercise, pre- and post-overload training period. A random-effects model of standardized mean difference (SMD) was estimated for each outcome measure based on the training-induced fatigue status (F-OR vs non-OR athletes), and the influence of methodological issues to detect PNS hyperactivity in F-OR was assessed by subgroup analyses. Pooled analysis showed that resting vagal-related HRV indices did not detect PNS hyperactivity in F-OR athletes (SMD₊ = -0.01; 95% confidence interval [CI] = -0.51, 0.50), and no statistical difference (P = .600) was found with non-OR athletes (SMD₊ = 0.15; 95% CI = -0.14, 0.45). However, subgroup analysis based on HRV parameter showed a moderate statistical increase in weekly averaged HRV in F-OR athletes (SMD₊ = 0.81; 95% CI = 0.35, 1.26), while isolated HRV values did not reach statistical significance (SMD₊ = -0.45; 95% CI = -0.96, 0.06). We observed a moderate and statistically significant increase in HRR indices among F-OR athletes (SMD₊ = 0.65; 95% CI = 0.44, 0.87), no changes for non-OR athletes (SMD₊ = 0.10; 95% CI = -0.15, 0.34), and statistically significant differences between F-OR and non-OR athletes (P < .001). Insufficient data prevented meta-analysis for post-exercise vagal-related HRV indices. Our findings show that when methodological factors are considered, HR-based indices are sensitive to increased PNS modulation in F-OR.

Influence of a Training Academy on the Parasympathetic Nervous System Reactivation of Firefighter Recruits-An Observational Cohort Study

Sudden cardiac death (SCD) is the leading type of line-of-duty death among firefighters. An inability to restore parasympathetic nervous system (PSNS) control after activity is associated with SCD. Post-exercise heart rate recovery (HRR) provides unique insight into reactivation of the PSNS. Thus, the purpose of this study was to examine longitudinal changes in HRR responses of 25 male firefighter recruits. HR data were collected after submaximal exercise at week 1 (W1), week 6 (W6), and week 15 (W15) of their training at an academy. Percent maximal heart rate (%MHR) measures were computed at each HRR time point (%MHR0, %MHR15, %MHR30, %MHR45, %MHR60, %MHR120, %MHR180) and absolute HRR values were calculated at 30 s (ΔHRR30), 60 s (ΔHRR60), 120 s (ΔHRR120), and 180 s (ΔHRR180). After controlling for age and percent body fat, there was no statistically significant interaction between Week × HRR (p = 0.730), and there were no changes in ΔHRR30, ΔHRR60, and ΔHRR120, and ΔHRR180 indices across time. However, %MHR at W6 and W15 was significantly lower than %MHR at W1 at every HRR time point (ps < 0.001). Therefore, although the firefighter recruit training academy elicited positive training adaptations, changes in PSNS reactivation after submaximal activity were not identified.

Faster Heart Rate Recovery Correlates With High-Intensity Match Activity in Female Field Hockey Players-Training Implications

Harry, K and Booysen, MJ. Faster heart rate recovery correlates with high-intensity match activity in female field hockey players-training implications. J Strength Cond Res 34(4): 1150-1157, 2020-The physical match demands of female field hockey are intense and may differ according to playing positions. In addition, conducting sports-specific field tests can assist coaches in determining their players' preparedness for competition. There is limited research regarding the match demands and relevance of field testing at premier league levels. Therefore, the aims were to describe the physical match demands of female premier league (amateur) field hockey, and to determine the relationships between match activity patterns and physical performance tests. Match activity and heart rate data were collected from 32 female participants using the Zephyr BioHarness 3 system. Participants also performed the Yo-Yo intermittent recovery (level 1) (n = 22), repeated sprint ability (n = 21), and the heart rate recovery (n = 16) tests. Moderate to large effect sizes were observed when defenders were compared with midfielders and forwards for time spent (%) in standing/walking and jogging (d = 0.64-1.30) in addition to the playing time (%) spent in the low-to-moderate and very high heart rate zones (d = 0.69-0.85). Heart rate recovery (10 s) correlated with the playing time (%) spent in sprinting (r = 0.73, p = 0.002). Heart rate recovery (60 s) and the Yo-Yo intermittent recovery test both correlated with the playing time (%) spent in running (r = 0.77, p = 0.0006 and r = 0.54, p = 0.01). The differences in physical match demands between positions emphasize the importance of training specificity at premier league levels. The heart rate recovery test can be used to assess a female field hockey player's capability to perform high-intensity match activity.

Heart Rate Recovery After Exercise Is Associated With Arrhythmic Events in Patients With Catecholaminergic Polymorphic Ventricular Tachycardia

Background:

Risk stratification in catecholaminergic polymorphic ventricular tachycardia remains ill defined. Heart rate recovery (HRR) immediately after exercise is regulated by autonomic reflexes, particularly vagal tone, and may be associated with symptoms and ventricular arrhythmias in patients with catecholaminergic polymorphic ventricular tachycardia. Our objective was to evaluate whether HRR after maximal exercise on the exercise stress test (EST) is associated with symptoms and ventricular arrhythmias.

Methods:

In this retrospective observational study, we included patients ≤65 years of age with an EST without antiarrhythmic drugs who attained at least 80% of their age- and sex-predicted maximal HR. HRR in the recovery phase was calculated as the difference in heart rate (HR) at maximal exercise and at 1 minute in the recovery phase (ΔHRR1′).

Results:

We included 187 patients (median age, 36 years; 68 [36%] symptomatic before diagnosis). Pre-EST HR and maximal HR were equal among symptomatic and asymptomatic patients. Patients who were symptomatic before diagnosis had a greater ΔHRR1′ after maximal exercise (43 [interquartile range, 25–58] versus 25 [interquartile range, 19–34] beats/min; P <0.001). Corrected for age, sex, and relatedness, patients in the upper tertile for ΔHRR1′ had an odds ratio of 3.4 (95% CI, 1.6–7.4) of being symptomatic before diagnosis ( P <0.001). In addition, ΔHRR1′ was higher in patients with complex ventricular arrhythmias at EST off antiarrhythmic drugs (33 [interquartile range, 22–48] versus 27 [interquartile range, 20–36] beats/min; P =0.01). After diagnosis, patients with a ΔHRR1′ in the upper tertile of its distribution had significantly more arrhythmic events as compared with patients in the other tertiles ( P =0.045).

Conclusions:

Catecholaminergic polymorphic ventricular tachycardia patients with a larger HRR following exercise are more likely to be symptomatic and have complex ventricular arrhythmias during the first EST off antiarrhythmic drug.

Relationship Between Repeated Sprint Ability, Aerobic Capacity, Intermittent Endurance, and Heart Rate Recovery in Youth Soccer Players

Rodríguez-Fernández, A, Sanchez-Sanchez, J, Ramirez-Campillo, R, Nakamura, FY, Rodríguez-Marroyo, JA, and Villa-Vicente, JG. Relationship between repeated sprint ability, aerobic capacity, intermittent endurance, and heart rate recovery in youth soccer players. J Strength Cond Res 33(12): 3406-3413, 2019-To investigate the relationship between repeated sprint ability (RSA) and several aerobic and anaerobic-related soccer-performance indicators, 45 youth soccer players (age 16.8 ± 0.1 years) were classified into "high" (HAF) or "low" aerobic fitness (LAF) (VO2max ≥ or <60 ml·kg·min, respectively) and completed an RSA test measuring best (RSAbest), mean (RSAmean), total sprint time (RSAtotal), and percent sprint decrement (Sdec). A laboratory VO2max test (LabTest) together with anaerobic threshold (VT) and peak speed was measured (vLabTest). In addition, a 20-m multistage shuttle run test (MSRT) and a soccer-specific test (TIVRE-Soccer test-TST) were completed. Heart rate (HR) and HR recovery (HRR) were measured during all tests. High aerobic fitness presented greater (p ≤ 0.05) performance in LabTest, MSRT and TST, at maximal effort, at VT, as well as faster HRR. RSA was similar between HAF and LAF. Contrary to HAF, LAF showed negative correlation between vLabTest with RSAmean (r = -0.6, p = 0.000) and Sdec (r = -0.4, p = 0.044). Also, LAF showed negative correlation between TST end speed (vTST) and RSAmean (r = -0.5, p = 0.005) and Sdec (r = -0.5, p = 0.003). In LAF, RSA was strongly correlated with locomotor factors (e.g., vTST; VT) in both laboratory and field tests. Athletes with high total HRR (>12.5%) in TST presented better (p ≤ 0.05) Sdec in the RSA test. The multiple regression revealed that the LAF vLabTest explained 44.9, 40.0, and 13.5% of the variance in RSAbest, RSAmean, and Sdec, respectively. Practitioners may consider these findings to optimize youth athletes' assessment and preparation processes.

The Fatigue and Fitness Test for Teams (FFITT): A practical option for monitoring athletes in a team as individuals

We developed the Fatigue and Fitness Test for Teams (FFITT) to address the challenges of monitoring players in a team simultaneously. The test, which takes 8 min for the entire team, incorporates subjective measures of well-being (RTT-Q), and objective measures of the autonomic system (HRR_60s) and neuromuscular function (SLJ). The aim of this study was to present the rationale for the FFITT as a novel athlete monitoring protocol and to measure the reliability of each component of the test. The internal consistency of the RTT-Q questions ranged from α = 0.69-0.92. All questions had an α > 0.83, with one exception of question 'Rate the well-being/stress your school/university/work is causing you to feel' which had an α = 0.69. The reliability of the HRR_60s and SLJ was high (R = 0.92, and 0.91 respectively). The absolute typical error of measurement (TEM) of the SLJ was 8 cm and HRR_60s was 3 beats. When expressed relatively the CV_TEM of HRR_60s was 8.4% and SLJ was 3.0%. Based on the TEM the HRR_60s and SLJ could detect medium and large changes in fatigue and fitness. In absolute terms this equates to more than 5 bpm (HRR_60s) and more than 13 cm (SLJ). The FFITT has the potential to satisfy both scientific principles and the coach's demands of a practical monitoring protocol for frequent use in a team.

Associations between measures of health-related physical fitness and cardiometabolic risk factors in college students

OBJECTIVE

To determine the influence of health-related fitness on cardiometabolic risk factors in college students.

PARTICIPANTS

75 traditional students (33 men and 42 women, 21.8±1.8 years old) at a university in southeastern U.S.

METHODS

Height, weight, waist circumference, body composition, blood pressure, lipids, glucose, insulin, c-reactive protein, and glucose tolerance were measured. Indices of insulin sensitivity were calculated. Aerobic and muscular fitness were measured. Regression and correlation analyses, and comparisons of cardiometabolic markers in low- vs high-fit participants were performed.

RESULTS

Men and women with low muscular fitness exhibited higher fasting insulin, and poorer insulin sensitivity index scores than those with high muscular fitness. In addition, women with high body fat percentage exhibited higher fasting and 2-hour insulin levels and lower insulin sensitivity index scores than those with low body fat percentages.

CONCLUSIONS

College students possessing low levels of health-related physical fitness exhibited less favorable cardiometabolic risk profiles.

A dose-response study of aerobic training for oxygen uptake, oxidative stress and cardiac autonomic function in type 2 diabetes mellitus: study protocol for a randomized controlled trial

Background

Cardiac autonomic neuropathy is a commonly overlooked complication of type 2 diabetes mellitus (T2DM) characterized by an imbalance between sympathetic and parasympathetic supply to the heart, which contributes to cardiovascular morbidity and mortality. T2DM has also been shown to negatively influence oxygen kinetics and increase oxidative stress, which may be linked to the development of various chronic complications. Aerobic training has been reported to improve oxygen uptake, antioxidant defense, and cardiac autonomic function in T2DM; however, the effects of varying doses of exercise on these variables are not known. Therefore, the aim of the present study is to explore the effects of manipulating training variables (volume and intensity) on the regulation of oxygen uptake response, oxidative stress, and cardiac autonomic function in patients with T2DM.

Methods

We will recruit 60 patients with T2DM, who will be randomly allocated into one of the three aerobic training groups: low-intensity, low-volume training; low-intensity, high volume-training; high-intensity, high-volume training; or to the control group receiving no supervised exercise. All participants will be assessed for the rate of oxygen uptake, levels of antioxidant enzymes and cardiac autonomic function at baseline and after 12 weeks of training. Secondary outcome measures will include cardiometabolic risk factors and body composition.

Discussion

Despite a large body of evidence on the efficacy of aerobic training in the prevention and treatment of T2DM, there is no unequivocal exercise prescription for the same. Oxygen kinetics and oxidative stress are highly sensitive to the magnitude of physical activity. It would therefore, be interesting to study their interaction with chronic exposure to various doses of exercises and explore the optimal volume and intensity to bring about improvements in these parameters.

Trial registration

Clinical Trials Registry – India, CTRI2017/08/009459. Registered on 23 August 2017. Retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2671-y) contains supplementary material, which is available to authorized users.

Effect of repeated-sprints on the reliability of short-term parasympathetic reactivation

This study determined the reliability of post-exercise heart rate recovery (HRR) and vagal-related HR variability (HRV) after repeated-sprints (RSs), and contrasted it with the smallest worthwhile change (SWC) of these indices. Fourteen healthy male participants performed on four occasions, separated by 7 days, five 30-m sprints interspersed by 25-s of recovery. Post-exercise HR during 10 min of seated rest was measured. HRR during the first 60-s of recovery was computed (HRR_60s). HRV indices were calculated in time and frequency domains during the last 5-min of the recovery. Absolute and relative reliability were assessed by typical error of measurement expressed as coefficient of variation (CV) and intraclass correlation coefficients (ICCs), respectively. Sensitivity was assessed comparing SWC to the typical error of measurement. CV ranged from 3.6% to 13.5% and from 6.3% to 109.2% for the HRR and HRV indices, respectively. ICCs were from 0.78 to 0.96 and from 0.76 to 0.92, respectively. HRR and HRV indices showed large discrepancies reliability. HRR_60s and the square root of the mean sum of the squared differences between R-R intervals presented the highest levels of both absolute and relative reliability. However, SWC was lower than the typical error of measurement, indicating insufficient sensitivity to confidently detect small, but meaningful, changes in HRR and HRV indices.

Heart rate recovery of individuals undergoing cardiac rehabilitation after acute coronary syndrome

BACKGROUND

An efficient cardiac rehabilitation programme (CRP) can improve the functional ability of patients after acute coronary syndrome (ACS).

OBJECTIVE

To examine the effect of a CRP on parasympathetic reactivation and heart rate recovery (HRR) measured after a 6-min walk test (6MWT), and correlation with 6MWT distance and well-being after ACS.

METHODS

Eleven normoweight patients after ACS (BMI<25kg/m²; 10 males; mean [SD] age 61 [9] years) underwent an 8-week CRP. Before (pre-) and at weeks 4 (W4) and 8 (W8) during the CRP, they performed a 6MWT on a treadmill, followed by 10-min of seated passive recovery, with HRR and HR variability (HRV) recordings. HRR was measured at 1, 3, 5 and 10min after the 6MWT (HRR1, HRR3, HRR5, HRR10), then modelized by a mono-exponential function. Time-domain (square root of the mean of the sum of the squares of differences between adjacent normal R-R intervals [RMSSD]) and frequency-domain (with high- and low-frequency band powers) were used to analyse HRV. Participants completed a mental and physical well-being questionnaire at pre- and W8. Exhaustion after tests was assessed by the Borg scale. Pearson correlation was used to assess correlations.

RESULTS

HRR3, HRR5 and HRR10 increased by 37%, 36% and 28%, respectively, between pre- and W8 (P<0.05), and were positively correlated with change in 6MWT distance (r=0.58, 0.66 and 0.76; P<0.05). Percentage change in HRR3 was positively correlated with change in well-being (r=0.70; P=0.01). Parasympathic reactivation (RMSSD) was improved only during the first 30sec of recovery (P=0.04).

CONCLUSION

Among patients undergoing a CRP after ACS, increased HRR after a 6MWT, especially at 3min, was positively correlated with 6MWT distance and improved well-being. HRR raw data seem more sensitive than post-exercise HRV analysis for monitoring functional and autonomic improvement after ACS.

Unobtrusive Estimation of Cardiorespiratory Fitness with Daily Activity in Healthy Young Men

Despite the importance of cardiorespiratory fitness, no practical method exists to estimate maximal oxygen consumption (VO₂max) without a specific exercise protocol. We developed an estimation model of VO₂max, using maximal activity energy expenditure (aEEmax) as a new feature to represent the level of physical activity. Electrocardiogram (ECG) and acceleration data were recorded for 4 days in 24 healthy young men, and reference VO₂max levels were measured using the maximal exercise test. aEE was calculated using the measured acceleration data and body weight, while heart rate (HR) was extracted from the ECG signal. aEEmax was obtained using linear regression, with aEE and HR as input parameters. The VO₂max was estimated from the aEEmax using multiple linear regression modeling in the training group (n = 16) and was verified in the test group (n = 8). High correlations between the estimated VO₂max and the measured VO₂max were identified in both groups, with a 15-hour recording being sufficient to produce a highly accurate VO₂max estimate. Additional recording time did not significantly improve the accuracy of the estimation. Our VO₂max estimation method provides a robust alternative to traditional approaches while only requiring minimal data acquisition time in daily life.

Reference values for and cross-validation of time to exhaustion on a modified Balke protocol in Norwegian men and women

The aims of the present study were to provide reference values for time to exhaustion (TTE) on a modified Balke treadmill protocol, and to perform a cross-validation of TTE as a measure of maximal oxygen consumption (VO_2max ), in Norwegian men and women 20-85 years of age. Reference values for TTE were derived from a national sample of 765 subjects. An additional sample of 119 subjects was included in the cross-validation (total n = 884), where prediction equations for VO_2max was established. A decline in TTE was seen with increased age. Prediction of VO_2max in an independent dataset (n = 319) resulted in a R²  = 0.78 and standard error of the estimate = 4.55 mL/kg/min. The observed-predicted bias was small (mean difference <1.24 mL/kg/min), whereas random error was considerable (95% limits of agreement ± 7.11-9.70 mL/kg/min) across age in both men and women. Despite limitations concerning the prediction of VO_2max on an individual level, TTE from the Balke protocol is a good measure of aerobic fitness in adults across a range of settings, and could be evaluated according to the suggested reference values.

Faster Heart Rate Recovery With Increased RPE: Paradoxical Responses After an 87-km Ultramarathon

The aim of this study was to determine the relationship between heart rate recovery (HRR) and an acute training "overload" by comparing HRR responses before and after an ultramarathon road race. Ten runners completed a standardized laboratory protocol ∼7 days before and between 2 and 4 days after participating in the 87-km Comrades Marathon. The protocol included muscle pain ratings, a 5-bound test, and 20 minutes of treadmill exercise at 70% of maximal oxygen uptake followed by 15 minutes of recovery. Respiratory gases and heart rate measurements were used to calculate steady-state exercise responses, HRR, and excess postexercise oxygen consumption (EPOC), and participants also provided a rating of perceived exertion (RPE) during exercise. The RPE was significantly increased (13 ± 2 vs. 11 ± 1) (p < 0.01), and HRR was significantly faster (35 ± 5 beats vs. 29 ± 4 beats) (p < 0.01) following the postrace vs. prerace submaximal exercise bout, with no significant changes in respiratory or heart rate parameters during exercise or in EPOC. Although previous studies have shown that faster HRR reflected an "adapted" state with enhanced training status, the current findings suggest that this may not always be the case. It follows that changes in HRR should be considered in the context of other factors, such as recent training load and RPE during submaximal exercise.

Kinetic Post-match Fatigue in Professional and Youth Soccer Players During the Competitive Period

BACKGROUND

No previous research has analysed kinetic fatigue of elite adult players and elite youth players during the competitive period.

OBJECTIVES

The aim of the present study was to analyse kinetic post-match fatigue in professional and youth soccer players during the competitive period.

MATERIALS AND METHODS

resting heart rate (HRrest), post-effort recovery heart rate (HRrecovery), rate of perceived exertion fatigue (RPEf), muscle soreness and blood samples with creatine kinase (CK) and resting lactate (La) from nine professional soccer players were measured immediately before, 24 hour and 48 hour after two official French first league matches (Ligue 1) whereas RPEf, HRrest, and 20m speed performance (speed-20 m) were measured in ten U-17 elite players immediately before, 24 hour and 48h after a friendly match.

RESULTS

for professionals, a soccer match elevated all physiological markers during the next 24 hours (P < 0.05); only HRrecovery remained significantly different 48 hours after the match (P < 0.05) whereas there was no variation of HRrest, RPEf, and speed-20m, which were elevated until 24h and got back to reference values 48 hours after the match (P < 0.05) for the U17 players. Comparing the two groups, HRrest results remained lower all the time for professionals, and RPEf was lower for U-17, 24 hours after the match (P < 0.05).

CONCLUSIONS

Independent of their level, professional soccer players, need 48 hours to recover after an official match. Professionals gain more fatigue than young players after a match, but recover as fast. Thus, they recover more efficiently especially due to a better physical condition and fitness training. It is expected that the results showed in the study help elite soccer and fitness coaches to manage the training load of the team according to the match.

Cardiac Parasympathetic Reactivation in Elite Soccer Players During Different Types of Traditional High-Intensity Training Exercise Modes and Specific Tests: Interests and Limits

Background:

The cardiac parasympathetic reactivation is currently used in soccer with a daily or weekly monitoring. However, previous studies have not investigated how this cardiac parasympathetic reactivation is in elite soccer players along different types of traditional high-intensity training exercise and specific tests. In this context, the present study aim to analyse it and to determine the interests and limits of this type of physiological information.

Objectives:

The present study aims to examine how different traditional training exercise modes affect the cardiac parasympathetic reactivation function in elite soccer players.

Materials and Methods:

Twenty-two international soccer players participating in UEFA Champion’s League took part in this study (age: 24.3 ± 4.2 years; height: 178.1 ± 6.2 cm; body mass: 80.3 ± 5.7 kg). Players performed different training methods including: short-duration intermittent exercises (INT) in-line and with changes of direction (COD) (10 - 10 seconds, 15 - 15 seconds, 30 - 30 seconds, e.g. an alternance of 10 - 10 seconds is 10 seconds of running according to the maximal aerobic speed (MAS) and 10-sec of recovery), INT including agility and technical skills (8 - 24-seconds), small-sided-games (SSGs) with and without goalkeepers (2 vs. 2, 3 vs. 3, 4 vs. 4), and repeated sprint ability (RSA) efforts (10 × 20 m, 10 × 30 m, 15 × 20 m). Heart rate (HR) decline was recorded 3 minutes after each exercise.

Results:

HR declines were greater after the RSA compared to SSGs (P < 0.001) and INT (P < 0.01), especially at 1 min post-exercise. In addition, when the analysis focused on each type of exercise, greater HR declines were observed in on-field players at 1 minute when there was: inclusion of goalkeepers in SSGs (for 2 vs. 2 and 3 vs. 3, P < 0.01); increase of sprint distances or number of sprint repetitions in RSA (P < 0.01); increase of intensity (% of maximal aerobic speed), and the use of COD or inclusion of technical skills during INT, especially for the 30 - 30-seconds.

Conclusions:

This study revealed that cardiac parasympathetic reactivation function varied after INT, RSA and SSG, but also according to the rules manipulation. Therefore, this study provides interesting information for the training monitoring and players’ recovery profile, with the aim of facilitating a more efficient planning and manipulation of training recovery strategies according to their fitness markers.

Heart rate recovery after maximal exercise is blunted in hypertensive seniors

Abnormal heart rate recovery (HRR) after maximal exercise may indicate autonomic dysfunction and is a predictor for cardiovascular mortality. HRR is attenuated with aging and in middle-age hypertensive patients, but it is unknown whether HRR is attenuated in older-age adults with hypertension. This study compared HRR among 16 unmedicated stage 1 hypertensive (HTN) participants [nine men/seven women; 68 ± 5 (SD) yr; awake ambulatory blood pressure (BP) 149 ± 10/87 ± 7 mmHg] and 16 normotensive [control (CON)] participants (nine men/seven women; 67 ± 5 yr; 122 ± 4/72 ± 5 mmHg). HR, BP, oxygen uptake (V̇o2), cardiac output (Qc), and stroke volume (SV) were measured at rest, at two steady-state work rates, and graded exercise to peak during maximal treadmill exercise. During 6 min of seated recovery, the change in HR (ΔHR) was obtained every minute and BP every 2 min. In addition, HRR and R-R interval (RRI) recovery kinetics were analyzed using a monoexponential function, and the indexes (HRRI and RRII) were calculated. Maximum V̇o2, HR, Qc, and SV responses during exercise were not different between groups. ΔHR was significantly different (P < 0.001) between the HTN group (26 ± 8) and the CON group (36 ± 12 beats/min) after 1 min of recovery but less convincing at 2 min (P = 0.055). BP recovery was similar between groups. HRRI was significantly lower (P = 0.016), and there was a trend of lower RRII (P = 0.066) in the HTN group compared with the CON group. These results show that in older-age adults, HRR is attenuated further with the presence of hypertension, which may be attributable to an impairment of autonomic function.

An Eighteen-Minute Submaximal Exercise Test to Assess Cardiac Fitness in Response to Aerobic Training

Romagnoli, M, Alis, R, Sanchis-Gomar, F, Lippi, G, and Arduini, A. An 18-minute submaximal exercise test to assess cardiac fitness in response to aerobic training. J Strength Cond Res 32(10): 2846-2852, 2018-We aimed to evaluate the utility of a submaximal heart rate recovery (HRR) test to monitor changes in cardiac fitness after aerobic training. Twenty healthy subjects were assigned to a control (n = 10) or a training (n = 10) group. Subjects in the training group performed 8 weeks of bicycle training, followed by 8 weeks of detraining. Heart rate recovery was assessed after exercises at 65% and 80% HRmax. The HRR test was performed at weeks 0 (W0), 4 (W4), 8 (W8), and 16 (W16) in the training group and at W0 and W8 in the control group. Heart rate recovery indices changed in response to training and detraining. Absolute HRR at 60, 120, and 180 seconds after exercise increased at both exercise intensities at W8 of training (p < 0.01, W8 vs. W0) and returned to the pretraining level after detraining (p > 0.05, W16 vs. W0). Time constants of fast HRR recovery (<1 minute) changed with training (p < 0.05-0.01, W8 vs. W0) and detraining (p > 0.05, W16 vs. W0) but only at 65% HRmax. At the end of the 3-minute recovery period, the predicted heart rate (HR) value (A0) and the HR recovered (Amax) from the monoexponential analysis changed with training (p < 0.05-0.01, W8 vs. W0) and detraining (p > 0.05, W16 vs. W0). We conclude that this novel submaximal HRR test is highly sensitive for monitoring cardiac fitness during training and detraining in healthy people. Because this test is simple, inexpensive, and the data are reliable and easy to analyze, we hope that it may be of interest to the sports science community.

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

PURPOSE

There is some evidence that measures of acute post-exercise recovery are sensitive to the homeostatic stress of the preceding exercise and these measurements warrant further investigation as possible markers of training load. The current study investigated which of four different measures of metabolic and autonomic recovery was most sensitive to changes in exercise intensity.

METHODS

Thirty-eight moderately trained runners completed 20-min bouts of treadmill exercise at 60, 70 and 80% of maximal oxygen uptake (VO2max) and four different recovery measurements were determined: the magnitude of excess post-exercise oxygen consumption (EPOCMAG), the time constant of the oxygen consumption recovery curve (EPOCτ), heart rate recovery within 1 min (HRR60s) and the time constant of the heart rate recovery curve (HRRτ) .

RESULTS

Despite significant differences in exercise parameters at each exercise intensity, only EPOCMAG showed significantly slower recovery with each increase in exercise intensity at the group level and in the majority of individuals. EPOCτ was significantly slower at 70 and 80% of VO₂max vs. 60% VO₂max and HRRτ was only significantly slower when comparing the 80 vs. 60% VO₂max exercise bouts. In contrast, HRR60s reflected faster recovery at 70 and 80% of VO₂max than at 60% VO₂max.

CONCLUSION

Of the four recovery measurements investigated, EPOCMAG was the most sensitive to changes in exercise intensity and shows potential to reflect changes in the homeostatic stress of exercise at the group and individual level. Determining EPOCMAG may help to interpret the homeostatic stress of laboratory-based research trials or training sessions.

Evaluation of an exercise field test using heart rate monitors to assess cardiorespiratory fitness and heart rate recovery in an asymptomatic population

PURPOSE

Measures of cardiorespiratory fitness (CRF) and heart rate recovery (HRR) can improve risk stratification for cardiovascular disease, but these measurements are rarely made in asymptomatic individuals due to cost. An exercise field test (EFT) to assess CRF and HRR would be an inexpensive method for cardiovascular disease risk assessment in large populations. This study assessed 1) the predictive accuracy of a 12-minute run/walk EFT for estimating CRF ([Formula: see text]) and 2) the accuracy of HRR measured after an EFT using a heart rate monitor (HRM) in an asymptomatic population.

METHODS

Fifty subjects (48% women) ages 18-45 years completed a symptom-limited exercise tolerance test (ETT) (Bruce protocol) and an EFT on separate days. During the ETT, [Formula: see text] was measured by a metabolic cart, and heart rate was measured continuously by a HRM and a metabolic cart.

RESULTS

EFT distance and sex independently predicted[Formula: see text]. The average absolute difference between observed and predicted [Formula: see text] was 0.26 ± 3.27 ml·kg-1·min-1 for our model compared to 7.55 ± 3.64 ml·kg-1·min-1 for the Cooper model. HRM HRR data were equivalent to respective metabolic cart values during the ETT. HRR at 1 minute post-exercise during ETT compared to the EFT had a moderate correlation (r=0.75, p<0.001).

CONCLUSION

A more accurate model to estimate CRF from a 12-minute run/walk EFT was developed, and HRR can be measured using a HRM in an asymptomatic population outside of clinical settings.

Estimation of maximal oxygen uptake via submaximal exercise testing in sports, clinical, and home settings

Assessment of the functional capacity of the cardiovascular system is essential in sports medicine. For athletes, the maximal oxygen uptake [Formula: see text] provides valuable information about their aerobic power. In the clinical setting, the (VO(2max)) provides important diagnostic and prognostic information in several clinical populations, such as patients with coronary artery disease or heart failure. Likewise, VO(2max) assessment can be very important to evaluate fitness in asymptomatic adults. Although direct determination of [VO(2max) is the most accurate method, it requires a maximal level of exertion, which brings a higher risk of adverse events in individuals with an intermediate to high risk of cardiovascular problems. Estimation of VO(2max) during submaximal exercise testing can offer a precious alternative. Over the past decades, many protocols have been developed for this purpose. The present review gives an overview of these submaximal protocols and aims to facilitate appropriate test selection in sports, clinical, and home settings. Several factors must be considered when selecting a protocol: (i) The population being tested and its specific needs in terms of safety, supervision, and accuracy and repeatability of the VO(2max) estimation. (ii) The parameters upon which the prediction is based (e.g. heart rate, power output, rating of perceived exertion [RPE]), as well as the need for additional clinically relevant parameters (e.g. blood pressure, ECG). (iii) The appropriate test modality that should meet the above-mentioned requirements should also be in line with the functional mobility of the target population, and depends on the available equipment. In the sports setting, high repeatability is crucial to track training-induced seasonal changes. In the clinical setting, special attention must be paid to the test modality, because multiple physiological parameters often need to be measured during test execution. When estimating VO(2max), one has to be aware of the effects of medication on heart rate-based submaximal protocols. In the home setting, the submaximal protocols need to be accessible to users with a broad range of characteristics in terms of age, equipment, time available, and an absence of supervision. In this setting, the smart use of sensors such as accelerometers and heart rate monitors will result in protocol-free VO(2max) assessments. In conclusion, the need for a low-risk, low-cost, low-supervision, and objective evaluation of VO(2max) has brought about the development and the validation of a large number of submaximal exercise tests. It is of paramount importance to use these tests in the right context (sports, clinical, home), to consider the population in which they were developed, and to be aware of their limitations.

Heart rate recovery after the 10-m incremental shuttle walking test in older adults with intellectual disabilities

Heart rate recovery (HRR) after exercise is an independent predictor for cardiovascular and all-cause mortality. To investigate the usefulness of HRR in cardiorespiratory exercise testing in older adults with intellectual disabilities (ID), the aims of this study were (a) to assess HRR in older adults with ID after the 10-m incremental shuttle walking test (ISWT) and (b) its association with personal characteristics (gender, age, distance walked on the ISWT, level of ID, genetic syndrome causing ID, autism, behavioral problems, and peak heart rate (HRpeak)). HRR was assessed after the 10-m incremental shuttle walking test in 300 older adults (>50 years) with borderline to profound ID. HRR was defined as the change from HRpeak during the ISWT to heart rate measured after 1, 2, 3, 4, and 5 min of passive recovery. The largest decrease in heart rate was in the first minute of recovery leveling off toward the fifth minute of recovery. An abnormal HHR (≤12 bpm) was seen in 36.1% of the participants with Down syndrome (DS) and in 30.7% of the participants with ID by other causes. After the fifth minute the heart rates of 69.4% of the participants with DS and of 61.4% of the participants with ID by other causes returned to resting levels. HRpeak and distance walked on the ISWT were positively related to all HRR measures. More severe ID was negatively related and having DS positively related to HRR after 3-5 min of recovery. The other characteristics were not significantly associated to HRR. HRR is a potentially useful outcome measure in cardiorespiratory fitness testing of older adults with ID with a direct, objective, and non-invasive measurement. Further research is needed to identify the relation between HRR and adverse health outcomes in this population.

Monitoring training status with HR measures: do all roads lead to Rome?

Measures of resting, exercise, and recovery heart rate are receiving increasing interest for monitoring fatigue, fitness and endurance performance responses, which has direct implications for adjusting training load (1) daily during specific training blocks and (2) throughout the competitive season. However, these measures are still not widely implemented to monitor athletes' responses to training load, probably because of apparent contradictory findings in the literature. In this review I contend that most of the contradictory findings are related to methodological inconsistencies and/or misinterpretation of the data rather than to limitations of heart rate measures to accurately inform on training status. I also provide evidence that measures derived from 5-min (almost daily) recordings of resting (indices capturing beat-to-beat changes in heart rate, reflecting cardiac parasympathetic activity) and submaximal exercise (30- to 60-s average) heart rate are likely the most useful monitoring tools. For appropriate interpretation at the individual level, changes in a given measure should be interpreted by taking into account the error of measurement and the smallest important change of the measure, as well as the training context (training phase, load, and intensity distribution). The decision to use a given measure should be based upon the level of information that is required by the athlete, the marker's sensitivity to changes in training status and the practical constrains required for the measurements. However, measures of heart rate cannot inform on all aspects of wellness, fatigue, and performance, so their use in combination with daily training logs, psychometric questionnaires and non-invasive, cost-effective performance tests such as a countermovement jump may offer a complete solution to monitor training status in athletes participating in aerobic-oriented sports.

Reliability of peak running speeds obtained from different incremental treadmill protocols

This study compared the values and reliability of peak running speeds from incremental treadmill protocols with different speed increments. Thirty-one men, recreational, endurance-trained runners performed, in an alternate order, three continuous tests with different speed increments (0.5, 1 and 2 km · h(-1)). The tests were repeated using the same order. Peak speed was identified as (1) the greatest speed that could be maintained for a complete minute (Vpeak-60s), (2) the speed of the last complete stage (Vpeak-C) and (3) the speed of the last complete stage added to the product of the speed increment and the completed fraction of the incomplete stage (Vpeak-P). The Vpeak-P was the most reliable, independent of the incremental test protocol (1.5% ≤ CV ≤ 1.8%), and differently from Vpeak-C (1.8% ≤ CV ≤ 2.6%) and Vpeak-60s (1.6% ≤ CV ≤ 3.8%), the Vpeak-P was only slightly influenced by the incremental test protocol. The results suggest that Vpeak-P should be used to assess aerobic capability and monitor training effects and that other determinations of peak speed should be avoided.

A systematic review on heart-rate recovery to monitor changes in training status in athletes

Heart-rate recovery (HRR) has been proposed as a marker of autonomic function and training status in athletes. The authors performed a systematic review of studies that examined HRR after training. Five cross-sectional studies and 8 studies investigating changes over time (longitudinal) met our criteria. Three out of 5 cross-sectional studies observed a faster HRR in trained compared with untrained subjects, while 2 articles showed no change as a result of training. Most longitudinal studies observed a corresponding increase in HRR and power output (training status). Although confounding factors such as age, ambient temperature, and the intensity and duration of the exercise period preceding HRR make it difficult to compare these studies, the available studies indicated that HRR was related to training status. Therefore, the authors conclude that HRR has the potential to become a valuable tool to monitor changes in training status in athletes and less well-trained subjects, but more studies and better standardization are required to match this potential.

C-reactive protein and heart rate recovery in middle-aged men with severe obstructive sleep apnea

OBJECTIVE

The study aimed to evaluate whether the inflammatory marker "high-sensitivity C-reactive protein (hsCRP)" level was associated with impaired heart rate recovery at 1 min after exercise termination (HRR-1) in middle-aged patients with severe obstructive sleep apnea (OSA).

METHODS

Thirty middle-aged male patients (40-64 years old) with severe OSA (apnea-hypopnea index [AHI] ≥ 30 h(-1)) and 30 subjects without OSA (AHI < 5 h(-1)), matched with age and body mass index (BMI), were recruited. All subjects underwent an overnight polysomnography and completed a symptom-limited maximal exercise test. Cardiopulmonary parameters included peak oxygen consumption (VO(2peak)) and heart rate response during and immediately after exercise. Fasting blood samples were drawn for hsCRP analysis.

RESULT

Patients with severe OSA had significantly higher hsCRP levels (0.18 vs. 0.07 mg/dl, P < 0.01), lower reduced HRR-1, peak heart rate, and VO(2peak) values than those in the controls. The hsCRP levels significantly correlated with HRR-1 in the OSA group (r = -0.69, P < 0.01) after adjustment for VO(2peak) (r = -0.66, P < 0.01). Furthermore, stepwise multiple regression analysis showed that HRR-1 and AHI were significant predictors of hsCRP levels in all participants (adjusted R(2) = 0.53, P < 0.01).

CONCLUSIONS

Blunted HRR was shown in middle-aged men with severe OSA, and it was associated with high hsCRP levels significantly.