Changes In Heart Rate Recovery Research Articles

Assessing criterion and longitudinal validity of submaximal heart rate indices as measures of cardiorespiratory fitness: A preliminary study in football

ObjectivesTo evaluate the criterion and longitudinal validity of field- and laboratory-derived heart rate (HR) indices of resting and submaximal fitness tests (SMFTs) as measures of cardiorespiratory fitness. DesignObservational, repeated measures. MethodsTwenty-nine semi-professional footballers participated. Laboratory assessments took place at the start and end of a preseason training period, whereby resting, SMFT HR-derived indices, and criterion measures of cardiorespiratory fitness (running economy [RE], maximal oxygen uptake [V̇O2 max] and aerobic speed [MAS]) were collected. Throughout this training period, two field-based SMFT protocols, prescribed at different intensities, were administered weekly. Individual slopes were calculated from the analysis of within-athlete change scores. Associations between laboratory and field measures were assessed via Pearson's correlation coefficient (r) and linear regression models. ResultsRelationships between SMFT HR-derived indices from laboratory and field were very-large for exercise HR (r = 0.74 to 0.87) and moderate to very-large for HR recovery (0.43 to 0.76). Moderate to very-large inverse relationships were observed between exercise HR and HR recovery with V̇O2 max and MAS (−0.41 to −0.78), whereas resting HR showed no substantial relationships. Changes in exercise HR showed large and very-large inverse correlations with preseason changes in V̇O2 max (−0.54 to −0.60) and MAS (−0.64 to −0.83). Relationships between changes in HR recovery and maximal cardiorespiratory criterion measures were moderate to large (−0.32 to −0.63). ConclusionSMFT exercise HR is a valid proxy measure of cardiorespiratory fitness irrespective of test setting, whereas the validity of HRR remains elusive and appears to vary between exercise intensities.

남자 대학생의 최대산소섭취량과 운동 후 회복률 간의 상관관계 분석

Purpose: This study aims to analyze changes in heart rate recovery (HRR) and lactate recovery rate (LRR) after the graded maximal exercise test in physically active male college students, and to investigate the relationship between three factors (V· O₂max, HRR, and LRR) closely related to exercise performance.BR Method: The subjects (22 males) conducted a one-way repeated measures ANOVA to analyze changes in heart rate recovery and lactate recovery rate according to the graded maximal exercise test, and Bonferroni correction was applied for multiple comparisons. In addition, the relationship between the three factors was verified by the Pearson correlation coefficient.BR Results: Heart rate recovery (9.18%, p.001) and lactate recovery rate (14.14%, p.01) showed the most significant recovery patterns 1 minute after the exercise load test. Maximum oxygen uptake (V· O₂max) did not appear to correlate with heart rate and lactate recovery rate, but heart rate recovery and lactate recovery rate showed a positive correlation (p.05).BR Conclusion: Monitoring heart rate recovery and lactate recovery rate is suggested as essential for developing programs to control exercise intensity parameters.

EXERCISE IMPROVES HEART RATE RECOVERY GREATER THAN STANDARD CARE IN TYPE 2 DIABETES

https://youtu.be/HRw1f_DoX-Q INTRODUCTION An attenuated heart rate recovery (HRR) immediately after exercise is considered an index of autonomic imbalance and is a predictor of all cause mortality in patients with type 2 diabetes (T2D). Because autonomic dysfunction in T2D patients has shown to be reversible with glycemic control, weight loss, and fitness gain, we investigated the effect of a 12 week aerobic exercise (AE) intervention compared to standard care on HRR in patients with T2D. METHODS T2D patients (n=32) were randomized to a 12-week AE intervention (n=19) or standard of care (n=13). The AE intervention consisted of supervised exercise training for 1h/day 5/wk for 12 weeks at 80% VO2peak. All subjects completed body composition analysis (DEXA), oral glucose tolerance test (OGTT), and maximal exercise testing before and after the study period. HRR was measured every minute for 10 minutes after cessation of maximal exercise testing. RESULTS Baseline HRR 1-minute values were negatively associated with ASCVD Risk (rho = 0.623; p = 0.002) and positively associated with VO2peak (rho = 0.361; p = 0.042). Body weight was unchanged in both control (p = 0.989) and AE group (p = 0.248) after the study period. Following AE training intervention, VO2peak increased by 7.4 ± 1.9% (p < 0.001), glucose metabolism, as measured by OGTT area under the curve (AUC), improved by 11.6 ± 6.0% (p = 0.040), and HRR 1-minute increased by 10.4 ± 6.1% (p = 0.234). The control group showed no significant changes as VO2peak increased by 0.7 ± 2.6% (p = 0.826), AUC improved by 3.1 ± 3.5% (p = 0.585), and HRR 1-minute increased 3.9 ± 9.0% (p = 0.915). Baseline HRR predicted change in HRR after the study period in the control group (rho = −0.817; p = 0.002) but not in the AE group (rho = −0.054, p = 0.860). Upon controlling for baseline HRR, AE group possessed a significantly higher post intervention HRR 1-minute value than control by 28.5% (p = 0.036). We found the AE group also had higher HRR values than control during the post-intervention 10-minute recovery resulting in a main effect of group (p < 0.001). CONCLUSIONS T2D patients with higher HRR, only receiving standard of care, are more susceptible to chronic detriments in HRR indicative of gradual autonomic function loss. To our knowledge these are the first data showing regular moderate-vigorous intensity exercise, which improved glycemic control and fitness gain independent of weight loss, outperforms standard of care alone for greater HRR.

Postoperative effects of bariatric surgery on heart rate recovery and heart rate variability

Background: Several studies have reported associations between obesity and autonomic dysfunction. However, little research has investigated the effect of bariatric surgery on heart rate recovery (HRR) in the treadmill test and heart rate variability (HRV) in 24-hour Holter monitoring. We investigated the effects of bariatric surgery on HRR and HRV, which are parameters related to autonomic dysfunction. Methods: We retrospectively investigated patients who underwent bariatric surgery in 2019. The treadmill test, 24-hour Holter monitoring, and echocardiography were performed before and 6 months after surgery. We compared the changes in HRR in the treadmill test and HRV parameters such as the time domain and spectral domain in 24-hour Holter monitoring before and after surgery. Results: Of the 40 patients who underwent bariatric surgery, 25 patients had the treadmill test or 24-hour Holter monitoring both before and after surgery. Body weight and body mass index significantly decreased after surgery (112.86±24.37 kg vs. 89.10±20.26 kg, p<0.001; 39.22±5.69 kg/m2 vs. 31.00±5.09 kg/m2, p<0.001, respectively). HRR significantly increased (n=23; 43.00±20.97 vs. 64.29±18.49, p=0.001). The time domain of HRV parameters increased (n=21; standard deviation of the N-N interval 123.57±28.05 vs. 152.57±39.49, p=0.002 and mean N-N interval 791.57±88.84 vs. 869.05±126.31, p=0.002).Conclusions: Our data showed that HRR after exercise and HRV during 24-hour Holter monitoring improved after weight reduction with bariatric surgery through improved cardiac autonomic function.

Heart rate recovery is useful for evaluating the recovery of exercise tolerance in patients with heart failure and atrial fibrillation

This study aimed to examine the factors that contribute to improvement of exercise tolerance in patients with heart failure (HF) and atrial fibrillation (AF) following cardiac rehabilitation. Our hypothesis is that parasympathetic values are important for recovering exercise tolerance in those patients. We included 84 consecutive patients with HF and AF (mean age: 69 ± 15 years, 80% men). All of the patients underwent a cardiopulmonary exercise test and had pre and post 5 month cardiac rehabilitation assessed. After 155 ± 11 days and 44 ± 8 sessions, 73 patients (86%) showed an increase in peak oxygen uptake (VO2) and VO2 at the anaerobic threshold. In univariate linear regression analysis, the % change in heart rate recovery, plasma B-type natriuretic peptide levels, resting heart rate, and the minute ventilation /carbon dioxide output slope were significantly related to that of peak VO2 (p < 0.01, p = 0.03, p = 0.02, p < 0.01, respectively). Stepwise multivariate linear regression analysis showed that the % change in heart rate recovery was independently related to that of peak VO2 (p < 0.05). Our results suggest that heart rate recovery is closely associated with recovery of exercise tolerance in patients with HF and AF after CR.

Sacubitril/Valsartan Improves Autonomic Function and Cardiopulmonary Parameters in Patients with Heart Failure with Reduced Ejection Fraction

Background: Heart rate recovery (HRR) is a marker of vagal tone, which is a powerful predictor of mortality in patients with cardiovascular disease. Sacubitril/valsartan (S/V) is a treatment for heart failure with reduced ejection fraction (HFrEF), which impressively impacts cardiovascular outcome. This study aims at evaluating the effects of S/V on HRR and its correlation with cardiopulmonary indexes in HFrEF patients. Methods: Patients with HFrEF admitted to outpatients’ services were screened out for study inclusion. S/V was administered according to guidelines. Up-titration was performed every 4 weeks when tolerated. All patients underwent laboratory measurements, Doppler-echocardiography, and cardiopulmonary exercise stress testing (CPET) at baseline and at 12-month follow-up. Results: Study population consisted of 134 HFrEF patients (87% male, mean age 57.9 ± 9.6 years). At 12-month follow-up, significant improvement in left ventricular ejection fraction (from 28% ± 5.8% to 31.8% ± 7.3%, p < 0.0001), peak exercise oxygen consumption (VO2peak) (from 15.3 ± 3.7 to 17.8 ± 4.2 mL/kg/min, p < 0.0001), the slope of increase in ventilation over carbon dioxide output (VE/VCO2 slope )(from 33.4 ± 6.2 to 30.3 ± 6.5, p < 0.0001), and HRR (from 11.4 ± 9.5 to 17.4 ± 15.1 bpm, p = 0.004) was observed. Changes in HRR were significantly correlated to changes in VE/VCO2slope (r = −0.330; p = 0.003). After adjusting for potential confounding factors, multivariate analysis showed that changes in HRR were significantly associated to changes in VE/VCO2slope (Beta (B) = −0.975, standard error (SE) = 0.364, standardized Beta coefficient (Bstd) = −0.304, p = 0.009). S/V showed significant reduction in exercise oscillatory ventilation (EOV) detection at CPET (28 EOV detected at baseline CPET vs. 9 EOV detected at 12-month follow-up, p < 0.001). HRR at baseline CPET was a significant predictor of EOV at 12-month follow-up (B = −2.065, SE = 0.354, p < 0.001). Conclusions: In HFrEF patients, S/V therapy improves autonomic function, functional capacity, and ventilation. Whether these findings might translate into beneficial effects on prognosis and outcome remains to be elucidated.

Effect of different doses of supervised aerobic exercise on heart rate recovery in inactive adults who are overweight or obese: results from E-MECHANIC.

Heart rate recovery (HRR) after exercise is an independent risk factor for cardiovascular disease and mortality. Regular aerobic exercise can improve HRR, yet little is known regarding the dose necessary to promote increases. The aim was to assess the impact of different doses of vigorous-intensity aerobic exercise on HRR in individuals with overweight/obesity. Data from 137 sedentary adults with overweight/obesity from E-MECHANIC were analyzed. Participants were randomized to either a moderate-dose exercise group (8kcal/kg body weight/week; KKW), a high-dose exercise group (20 KKW), or a non-exercise control group. HRR was defined as the difference between peak heart rate (HR) during a graded exercise test and the HR after exactly 1min of active recovery at 1.5 mph and level grade. Change in HRR did not differ significantly by exercise group; therefore, the data from both exercise groups were combined. The combined exercise group showed an improvement in HRR of 2.7bpm (95% CI 0.1, 5.4; p = 0.04) compared to the control group. Those participants who lost more weight during the intervention (non-compensators) increased HRR by 6.2bpm (95% CI 2.8, 9.5; p < 0.01) compared to those who lost less weight (compensators). Multiple linear regression models indicated that improvements in HRR are independently associated with increases in VO2peak (β = 0.4; 95% CI 0.1, 0.7; p = 0.04) but also influenced by concomitant weight loss (β = 0.6; 95% CI 0.2, 1.1; p = 0.01). Exercise-induced improvements in 1-min HRR are likely due to increases in cardiorespiratory fitness as well as concomitant weight loss.

Heart Rate Recovery Changes during Competition Period in High-Level Basketball Players

Research background and hypothesis. Replete schedule of competitions and intense training are features of contemporary team sports. Athletes, especially the most involved ones, may not have enough time to recover. As a consequence, aggregated fatigue can manifest in some undesirable form and affect athlete’s performance and health.Research aim. The aim of this study was to evaluate the changes in heart rate recovery (HRR) and investigate possible relations with sport-specifi c measures of effi cacy in professional basketball players during competition season.Research methods. Eight male high-level basketball players (mean ± SD, body mass, 97.3 ± 11.33 kg; height 2.02 ± 0.067 m, and age 23 ± 3.12 years) were investigated. The same basketball specifi c exercise was replicated several times from September till April during the practice sessions in order to assess the personal trends of HRR. Heart rate monitoring was performed using POLAR TEAM SYSTEM. Investigated athletes were ranked retrospectively according to the total amount of minutes played and the coeffi cients of effi cacy. Research results. There were signifi cant differences in the trends of HRR between the investigated players. The most effective players showed decreasing trends of HRR in all cases of ranking.Discussion and conclusions. Research fi ndings have shown that the quality of heart rate recovery differs between basketball players of the same team and could be associated with sport-specifi c effi cacy and competition playing time.Keywords: adaptation, autonomic control, monitoring training.

Heart rate recovery as a sensitive indicator of physical activity changes in perimenopausal and postmenopausal women

Heart rate recovery (HRR), which is defined as the rate of heart rate decline after cessation of exercise, is an important indicator of exercise tolerance. The aim of this study was to investigate the effect of a 4-month moderate reduction in physical activity on pre-exercise and exercise heart rate (HR) as well as HRR after exercise cessation in perimenopausal and postmenopausal women. 10 physically active females, 62.5±3.0 years old, participated in this study. They performed an 8-min constant power output (~50W) cycling exercise at an intensity corresponding to about 65% of maximal heart rate. Heart rate was measured continuously starting from 1 minute before exercise, during the exercise test and 3 min after exercise cessation. Furthermore, before and after exercise, blood pressure (BP) and tympanic temperature (Tt) were measured. The exercise test was performed twice, before and after a 4-month reduction in physical activity. 4 months of the slight reduction in physical activity (by ~16%) did not cause any changes in pre-exercise and exercise HR, however, significantly higher HR during the 1st min after exercise (p=0.03), as well slower HRR (p=0.03), were reported. No effects of the reduction in physical activity were observed in resting and post-exercise BP and Tt. Even a slight reduction in physical activity is accompanied by a lower rate of HRR , which indicates a decrease in exercise tolerance. These results indicate that HRR is a sensitive indicator of physical capacity also in peri- and postmenopausal women, since the changes in HRR in response to physical activity level occur earlier than changes in pre-exercise and exercise heart rate. heart rate, heart rate recovery, physical activity in the elderly

MENTAL FATIGUE DOES NOT AFFECT HEART RATE RECOVERY BUT IMPAIRS PERFORMANCE IN HANDBALL PLAYERS

ABSTRACT Introduction: This study involved an analysis of the impact of mental fatigue on heart rate recovery (HRR), subjective measures of fatigue and intermittent running performance in handball players. Objective: This study was aimed at (1) examining the effects of an induced state of mental fatigue on the aerobic performance of handball players, as measured by the Yo-Yo IR1 test, and (2) exploring possible changes in heart rate regulation through HRR analysis. Methods: Twelve handball players (age: 17.50 ± 3.63 years; 5 ± 2.2 years of practice) undertook a Yo-Yo IR1 test on two occasions, separated by an interval of at least 72 hours. The Yo-Yo IR1 test was preceded by a 30-min treatment, consisting of the Stroop Color-Word Test, to induce mental fatigue. Participants in the control condition watched an emotionally neutral video. Results: Higher ratings of mental fatigue and mental effort following the Stroop Test were observed for the experimental group. No differences in motivation were observed between conditions. Moreover, the induction of mental fatigue impaired running performance and led to a higher RPE during the Yo-Yo IR1 test. Notwithstanding, no changes in HRR or blood lactate levels were observed across conditions. Conclusion: Altogether, these results suggest that mental fatigue impairs intermittent running performance, without affecting HRR values. Level of Evidence III; Case-Control study.

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 (HRR60s). 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. HRR60s 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.

Comparison of the Changes in Heart Rate Recovery Before and after Cardiac Rehabilitation in Patients Undergoing the Coronary Artery Bypass Surgery Based on the Risk Factors for Heart Failure, Diabetes and Smoking

Comparison of the Changes in Heart Rate Recovery Before and after Cardiac Rehabilitation in Patients Undergoing the Coronary Artery Bypass Surgery Based on the Risk Factors for Heart Failure, Diabetes and Smoking

In-season changes in heart rate recovery are inversely related to time to exhaustion but not aerobic capacity in rowers.

To determine if in-season changes in heart rate recovery (HRR) are related to aerobic fitness and performance in collegiate rowers. Twenty-two female collegiate rowers completed testing before and after their competitive season. Body fat percentage (BF%) was determined by dual-energy X-ray absorptiometry. Maximal aerobic capacity (VO2max ) and time to exhaustion (Tmax ) were determined during maximal rowing ergometer testing followed by 1minute of recovery. HRR was expressed absolutely and as a percentage of maximal HR (HRR%1min ). Variables were compared using paired Wilcoxon tests. Multivariable regression models were used to predict in-season changes in HRR using changes in VO2max and Tmax , while accounting for changes in BF%. From preseason to post-season, VO2max and BF% decreased (3.98±0.42 vs 3.78±0.35L/min, P=.002 and 23.8±3.4 vs 21.3±3.9%, P<.001, respectively), while Tmax increased (11.7±1.3 vs 12.6±1.3min, P=.002), and HRR%1min increased (11.1±2.7 vs 13.8±3.8, P=.001). In-season changes in VO2max were not associated with HRR%1min (P>.05). In-season changes in Tmax were related to changes in HRR%1min (β=-1.67, P=.006). In-season changes in BF% were not related to changes in HRR (P>.05 for all). HRR1min and HRR%1min were faster preseason to post-season, although the changes were unrelated to VO2max . Faster HRR%1min post-season was inversely related to changes in Tmax . This suggests that HRR should not be used as a measure of aerobic capacity in collegiate rowers, but is a promising measure of training status in this population.

Assessing Overreaching With Heart-Rate Recovery: What Is the Minimal Exercise Intensity Required?

Faster heart-rate recovery (HRR) after high to maximal exercise (≥90% of maximal heart rate) has been reported in athletes suspected of functional overreaching (f-OR). This study investigated whether this response would also occur at lower exercise intensity. Responses of HRR and rating of perceived exertion (RPE) were compared during an incremental intermittent running protocol to exhaustion in 20 experienced male triathletes (8 control subjects and 13 overload subjects led to f-OR) before and immediately after an overload training period and after a 1-wk taper. Both groups demonstrated an increase in HRR values immediately after the training period, but this change was very likely to almost certainly larger in the f-OR group at all running intensities (large to very large differences, eg, +16 ± 7 vs +3 ± 5 beats/min, in the f-OR and control groups at 11 km/h, respectively). The highest between-groups differences in changes in HRR were reported at 11 km/h (13 ± 4 beats/min) and 12 km/h (10 ± 6 beats/min). A concomitant increase in RPE at all intensities was reported only in the f-OR group (large to extremely large differences, +2.1 ± 1.5 to +0.7 ± 1.5 arbitrary units). These findings confirm that faster HRR does not systematically predict better physical performance. However, when interpreted in the context of the athletes' fatigue state and training phase, HRR after submaximal exercise may be more discriminant than HRR measures taken after maximal exercise for monitoring f-OR. These findings may be applied in practice by regularly assessing HRR after submaximal exercise (ie, warm-up) for monitoring endurance athletes' responses to training.

In-season Changes In Heart Rate Recovery Are Related To Time To Exhaustion, But Not Aerobic Capacity In Collegiate Rowers

In-season Changes In Heart Rate Recovery Are Related To Time To Exhaustion, But Not Aerobic Capacity In Collegiate Rowers

In-Season Changes in Heart Rate Recovery are not Related to Aerobic Fitness in Collegiate Intermittent Sport Athletes

In-Season Changes in Heart Rate Recovery are not Related to Aerobic Fitness in Collegiate Intermittent Sport Athletes

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.

The Development of Functional Overreaching Is Associated with a Faster Heart Rate Recovery in Endurance Athletes.

PurposeThe aim of the study was to investigate whether heart rate recovery (HRR) may represent an effective marker of functional overreaching (f-OR) in endurance athletes.Methods and ResultsThirty-one experienced male triathletes were tested (10 control and 21 overload subjects) before (Pre), and immediately after an overload training period (Mid) and after a 2-week taper (Post). Physiological responses were assessed during an incremental cycling protocol to exhaustion, including heart rate, catecholamine release and blood lactate concentration. Ten participants from the overload group developed signs of f-OR at Mid (i.e. -2.1 ± 0.8% change in performance associated with concomitant high perceived fatigue). Additionally, only the f-OR group demonstrated a 99% chance of increase in HRR during the overload period (+8 ± 5 bpm, large effect size). Concomitantly, this group also revealed a >80% chance of decreasing blood lactate (-11 ± 14%, large), plasma norepinephrine (-12 ± 37%, small) and plasma epinephrine peak concentrations (-51 ± 22%, moderate). These blood measures returned to baseline levels at Post. HRR change was negatively correlated to changes in performance, peak HR and peak blood metabolites concentrations.ConclusionThese findings suggest that i) a faster HRR is not systematically associated with improved physical performance, ii) changes in HRR should be interpreted in the context of the specific training phase, the athletes perceived level of fatigue and the performance response; and, iii) the faster HRR associated with f-OR may be induced by a decreased central command and by a lower chemoreflex activity.

Exercise training improves heart rate recovery in women with breast cancer.

PurposeTo determine whether exercise training improves autonomic function in women with breast cancer (BC).MethodsFifty-one patients (aged between 39 and 72 years) with a history of primary invasive BC within the previous 5 years and enrolled in the Mediterranean diet-based DIANA (Diet and Androgens)-5 Trial were subdivided in two groups: a ET group (n = 25) followed a formal ET program of moderate intensity (3 session/week on a bicycle at 60–70% VO2peak for 3 months, followed by one session/week until 1-year follow-up), while a control group (n = 26) did not perform any formal ET. At baseline and after 1-year, all patients underwent cardiopulmonary exercise stress test (CPET). Heart rate recovery (HRR) was calculated as the difference between heart rate at peak exercise and heart rate at first minute of the cool-down period.ResultsThere were no significant differences between groups in baseline anthropometrical, BC characteristics, metabolic profile, CPET parameters and HRR. Compared to controls, at 1-year follow-up ET group showed a significant improvement in VO2peak (from 12.6 ± 3.0 to 14.5 ± 3.3 ml/kg/min, p < 0.001; p < 0.001 between groups); and in HRR (from 17.6 ± 6.4 to 23.0 ± 8.3 beats/min, p < 0.001; p < 0.001 between groups). In ET group the changes in HRR directly correlated with changes in VO2peak (r = 0.58, p = 0.002).ConclusionsModerate intensity exercise training in BC survivors is associated with improvement of autonomic function. Whether the improvement of sympatho-vagal balance may favorably modulate some of the pathophysiological mechanisms implied in cancer evolution need further investigation.

Tapering for Marathon and Cardiac Autonomic Function

The purpose of this study was to investigate changes in post-exercise heart rate recovery (HRR) and heart rate variability (HRV) during an overload-tapering paradigm in marathon runners and examine their relationship with running performance. 9 male runners followed a training program composed of 3 weeks of overload followed by 3 weeks of tapering (-33 ± 7%). Before and after overload and during tapering they performed an exhaustive running test (T(lim)). At the end of this test, HRR variables (e.g. HRR during the first 60 s; HRR(60 s)) and vagal-related HRV indices (e.g. RMSSD(5-10 min)) were examined. T(lim) did not change during the overload training phase (603 ± 105 vs. 614 ± 132 s; P = 0.992), but increased (727 ± 185 s; P = 0.035) during the second week of tapering. Compared with overload, RMSSD(5-10 min) (7.6 ± 3.3 vs. 8.6 ± 2.9 ms; P = 0.045) was reduced after the 2(nd) week of tapering. During tapering, the improvements in T(lim) were negatively correlated with the change in HRR(60 s) (r = -0.84; P = 0.005) but not RMSSD(5-10 min) (r = -0.21; P = 0.59). A slower HRR during marathon tapering may be indicative of improved performance. In contrast, the monitoring of changes in HRV as measured in the present study (i.e. after exercise on a single day), may have little or no additive value.