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Objectives: Heart rate recovery (HRR) after exercise is clinically important as a predictor of mortality. In addition, HRR is an indicator of cardiac autonomic activity, since increased vagal activity and diminished sympathetic activity return the heart rate to resting conditions after exercise. The previous attempts to model HRR using polynomial, first-order and second-order modelling have produced mixed results. In this study, we hypothesised that the double-exponential fit would model the HRR more accurately than the single-exponential fit as it would capture the activity of both autonomic arms responsible for heart rate decay and investigated the outcome of these two models on the HRR data following a maximal exercise. Materials and Methods: Exponential curve fitting was done on a set of previously published data from our laboratory. The HRR data were acquired from 40 male participants (19–38 years) after a maximal treadmill exercise. The normalised HRR data from a 5-min time window from maximal heart rate were fitted using single and double-exponential curves, to obtain, respectively, the time constants Tau and, Tau 1 and Tau 2. The goodness-of-fit of the model was assessed with Chi-square values computed for each participant data set with both models. Considering that Chi-square of zero is a perfect fit, and therefore, smaller Chi-square values indicate a better fit than larger values, we computed the difference in the Chi-square values (??2 ) between the models by subtracting the Chi-square value of the double-exponential fit from the Chi-square value of the singleexponential fit. This was based on the premise that if the calculated ??2 is positive, it would indicate a better fit with double-exponential than single-exponential decay model. The data are presented as mean ± standard deviation. Comparisons were made with Student’s t-test. Results: Data from four participants were excluded for technical reasons. The Tau of the single-exponential fit was 65.50 ± 12.13 s, while Tau 1 and Tau 2 of the double-exponential fit were 43.75 ± 18.96 s and 120.30 ± 91.32 s, respectively, the Tau 1 value being significantly lower than the Tau 2 value (P < 0.0001). Remarkably among the 36 participants, the difference in the Chi-square value was positive (127.2 ± 171.04) in 22 subjects and zero or marginally negative (?0.17 ± 0.31) in 14 subjects. Conclusion: Our results indicate that the double-exponential model fitted the HRR data better than the single-exponential model in almost two-thirds (61%) of our study population. In the remaining participants, the goodness-of-fit was nearly equivalent for both fits with no evidence of superior modelling with the singleexponential fit. Our data show that while the single-exponential fit is sufficient for modelling the HRR of 14 subjects, it was less efficient for fitting the data of most participants. In comparison, the double-exponential curve fit effectively modelled 100% of our study population. Given our findings, we conclude that the doubleexponential model is more inclusive and better represented the HRR data of our study population than the singleexponential model.
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Background: Heart rate recovery at 1st min (HRR 1 min) after graded treadmill exercise (GTX) is a predictor of parasympathetic function. Impaired HRR 1 min and obesity are strong predictors of metabolic syndrome and cardiovascular disorders. This study is done to asses HRR 1 min on apparently healthy obese young adults with body mass index (BMI) ?30, without any other metabolic syndrome components. Aims and Objectives: The objective of this study was to assess the parasympathetic function by estimating HRR 1 min after exercise in apparently healthy obese young adults of 18–30 years of age without any metabolic syndrome components and is compared with age- and gender-matched controls with normal BMI. Materials and Methods: Fifty obese young adults with BMI ?30 without any other metabolic syndrome component and 50 age- and gender-matched controls with BMI ?24.9 were selected and subjected to GTX according to modified Bruce protocol. Maximum heart rate reached during exercise (HRmax) and heart rate at 1st min of recovery phase (HR1min) were recorded. HRR 1 min was calculated as HRmax-HR1min and was analyzed. Results: This study showed significantly attenuated HRR 1 min in obese young adults compared to age- and gender-matched controls (mean 24.02 ± 8.87 vs. 42.42 ± 5.3, P < 0.001). Conclusion: HRR 1 min was significantly decreased in obese young adults, indicating attenuated parasympathetic function, who are at higher risk of developing chronic cardiovascular and other metabolic disorders.
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Objective:To observe the relationship of ventilatory efficiency to cardiac function, especially heart rate recovery after exercise for patients with chronic obstructive pulmonary disease (COPD). Methods:From January, 2019 to December, 2020, 190 patients with COPD were recruited for Cardiopulmonary Exercise Testing. The general condition, medical history and medication history, lung function test and parameters of Cardiopulmonary Exercise Testing were recorded. They were divided into normal group and delay group according to whether the heart rate decline more than twelve beats within a minute after Cardiopulmonary Exercise Testing. Results:There were 89 patients (46.84%) in the delay group. Compared with the normal group, the delay group were older (Z = 2.282, P < 0.05), with less ratio of force exiratory volume in the first second in prediction (FEV1.0%) (Z = 3.626, P < 0.001), maximum power (t = 5.547, P < 0.001), breath reserve (BR) (t = 2.122, P < 0.05) and higher minimum ventilation equivalent of carbon dioxide (VE/VCO2nadir) (Z = 3.296, P = 0.001). Logistic regression showed that the COPD severity, VE/VCO2nadir and BR correlated with heart rate recovery. After adjusting for gender, age, body mass index and COPD severity, VE/VCO2nadir was an independent risk factor for delayed heart rate recovery (OR = 1.203, 95%CI 1.032 to 1.873, P = 0.004), and the best cut-off point was 33.15 (AUC = 0.6387, 95%CI 0.5595 to 0.7178, P = 0.001). Conclusion:The ventilatory inefficiency may increase the risk of abnormal heart rate recovery after exercise in COPD patients.
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Objective:To explore the effect of individualized aerobic training combined with resistance training on heart rate recovery and exercise capacity among patients with obstructive sleep apnea syndrome (OSAS) and explore possible mechanisms.Methods:Forty middle-aged patients with moderate to severe OSAS were randomly assigned to an observation group (OG, n=20) or a control group (CG, n=20). Both groups were given routine health guidance and motor training, while the OG additionally underwent individualized aerobic exercise training at 60%~75% of their peak power and resistance training loaded at 60%~80% of their ten-times maximum repetition figure. The training was three times a week for 3 months. Both groups underwent cardiopulmonary exercise testing and polysomnography before and after the 12-week intervention. The changes in their sleep apnea hypopnea index (AHI), oxygen desaturation index (ODI) and lowest oxygen saturation (L-SAO 2) were collected. Exercise capacity indicators such as peak oxygen uptake (VO 2peak), peak power, anaerobic threshold and sitting heart rate recovery (HRR) 1, 2 and 3 minutes after the test were recorded (denoted as HRR-1, HRR-2 and HRR-3). Results:There were no significant differences between the two groups in any of the measurements before the intervention. Afterward the average AHI, ODI and L-SAO 2 values of the observation group had all improved significantly compared with those before the training and compared with the control group′s values after the training. After the training, the VO 2peak and peak power of the observation group had also improved significantly compared with before the training and compared with the control group. HRR-1, HRR-2 and HRR-3 were all significantly higher in the observation group than before the training and higher than the control group′s values after the training. Conclusion:Combining aerobic and resistance training can improve the exercise ability and heart rate of middle-aged patients with moderate to severe OSAS, and also reduce the severity of their OSAS to some extent.
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Abstract Aims: The purpose of this study was to evaluate the acute effects of different resistance exercise (RE) volumes on postexercise cardiac autonomic modulation in men. Methods: Ten young men (25.5 ± 4.9 years, 24.8 ± 2.1 kg/m2) performed 3 trials of RE with 1, 2 or 3 sets (48-72 h between each trial) of 10-12 repetitions (70% of the one-maximum repetition) of bench press, leg press, and barbell row. Heart rate variability (HRV) was assessed at the 1st and 5th minutes of recovery (fast phase) and 3 consecutive 5-minute intervals from the 5th to 20th minute of recovery (slow phase). Parasympathetic and global modulations were assessed using the SD1 and SD2 indices of HRV, respectively. The comparison of the interventions was performed using the Friedman and Wilcoxon tests (p<0.05). Results: Lower parasympathetic modulation was identified after 2 and 3 sets compared to 1 set in both the fast and slow recovery phases (p= 0.004-0.05). Lower global modulation was identified after 3 sets compared to 1 set in both fast and slow recovery phases (p= 0.005-0.01). No differences in post-exercise parasympathetic and global modulation were observed between 2 and 3 sets. Conclusion: We concluded that 2 and 3 sets of RE compared to 1 set promoted higher autonomic reduction on the post-exercise phase, which should be considered by coaches when prescribing an RE program for untrained participants or intend to manipulate the postexercise organic recovery.
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Humans , Male , Exercise , Resistance Training , Heart Rate , Statistics, Nonparametric , Non-Randomized Controlled Trials as TopicABSTRACT
Objective To investigate the relation of post-exercise heart rate recovery(HRR)with exercise capacity, and the predictive value on long-term prognosis in patients of ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI). Methods A total of 260 patients were investigated from July 2011 to December 2014. All the patients were conducted cardiopulmonary exercise testing(CPET)within 30 days after STEMI, and heart rate recovery at 1 minute (HRR1)were calculated. The correlation between HRR with exercise tolerance was analysed. The median followup duration was 55 months(42,72), and the cardiovascular endpoint events were collected. Results The mean HRR1 was 26.0±12.2 beats in the whole study population who completed CPET.(1)HRR1 was positively correlated to peak oxygen uptake(VO2peak)(r=0.129, P<0.001).Multiple linear regression analysis demonstrated that VO2peak was independently positively associated with HRR1. (2) Cardiovascular endpoint events occurred in 60 cases (23.1%). Single factor screening through Cox regression model showed that decreased HRR1 (HRR1 ≤ 12 beats)(P=0.010)significantly correlated with the cardiovascular endpoint events. After adjusted by multiple factors, the risk of cardiovascular endpoint events in the group of decreased HRR(HRR1 ≤ 12 beats)was 2.671 times as the group of HRR1>12 beats. Conclusions Decreased HRR1 is associated with lower exercise tolerance, and it shows signifi cant prognostic values in increasing cardiovascular endpoint events in STEMI patients treated with primary PCI.
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Objective To explore the characteristics of postoperative heart rate recovery (HRR)in children who underwent primary radical repair of tetralogy of Fallot(TOF).Methods A total of 32 patients who underwent pri-mary radical repair of TOF were chosen as the TOF group(18 male,14 female,aged from 7 to 15 years old,ranged from 5 to 12 years after primary radical repair of TOF),and 86 healthy children were selected as the healthy control group (42 male,44 female,aged from 6 to 14 years).All children had the treadmill test in Shanghai Children's Medical Cen-ter from January 2013 to December 2015.The data of HRR in 2 groups were reviewed,and the data of HRR were also analyzed in TOF group who had ventricular tachycardia during treadmill test and they were treated with β-blocker.The maximal heart rate(HRmax)at the peak exercise level and the heart rate in 1-6 minute(HRR1-HRR6)in the recovery period were measured and the HRR1-HRR6 was defined as difference between the HRmax and the heart rate in 1-6 minutes during the recovery period.Results The heart rate in first 2 minutes after treadmill exercise showed the rapid recovery in both TOF group and the healthy control group.It recovered slowly after the third minute in two groups.The healthy control group reached the steady HRR period after the fifth minute,whereas TOF group entered the steady HRR period after the sixth minute,and later in the TOF group it reached steady HRR period.There was no difference in HRmax in 2 groups(P＞0.05).But there were significant differences in the resting heart rate[(82.3 ± 3. 4)times/min vs.(79.0 ± 2.5)times/min],and the levels of HRR1-HRR4 minutes were (25.9 ± 1.5)%,(39.4 ± 1.6)%, (43.0 ± 1. 6 )%,and (44. 7 ± 1. 8 )% in TOF group,respectively;while in the healthy control group they were (26.3 ± 1.3)%,(40.0 ± 1.1)%,(43.8 ± 0.7)%,and(45.4 ± 1.4)%;the incidence of ventricular premature beat was 18/32 cases(56.3%)and 5/86 cases(5.8%)during treadmill test between 2 groups (t＝5.77,5. 59,10.32, 18.65,10.66,χ2＝37.80,all P＜0.05).β-blocker treatment was given to 7 cases who had ventricular tachycardia during treadmill test in TOF group.After treatment,the resting heart rate was (77.6 ± 2.6)times/min,significantly de-creased(t＝3.93,P＝0.01),the level of HRR1-HRR4 was(26.3 ± 1.9)%,(39.8 ± 0.9)%,(43.8 ± 0.8)%, (46.2 ± 1. 3)%,respectively,which was significantly increased (t＝2.49,4.63,8.30,7.90,all P＜0.05).The inci-dence of ventricular tachycardia(2/7 cases,28.6%)decreased significantly(χ2＝7.78,P＝0.02).Conclusions There exists cardiac autonomic dysfunction in children who had the primary radical repair of TOF,which is related to the occurrence of ventricular arrhythmia and may influence the long-term prognosis of TOF.HRR can be used as an important indicator to assess and reassess the cardiac autonomic function in patients after TOF repair.
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This study aimed to assess the blood pressure (BP), cardiac autonomic modulation at rest, in physical exercise and in the recovery in untrained eutrophic (E) and overweight (O) youth. The body mass index (BMI), waist circumference (WC), systolic BP-SBP (E: 109.80 ± 10.05; O: 121.85 ± 6.98 mmHg) and diastolic BP - DBP (E: 65.90 ± 7.28; O: 73.14 ± 12.22 mmHg) were higher in overweight and the heart rate recovery (%HRR) was lower as compared with E volunteers. The BMI was associated with SBP (r= 0.54), DBP (r= 0.65), load on the heart rate variability threshold - HRVT (r= -0.46), %HRR 2' (r= -0.48) and %HRR 5' (r= -0.48), and WC was associated with SBP (r= 0.54), DBP (r= 0.64) and HRR 2' (r= -0.49). The %HRR was associated to SBP, DBP and HRVT. In summary, the anthropometric variables, BP and cardiac autonomic modulation in the recovery are altered in overweight youth.
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Humans , Male , Female , Adult , Exercise , Heart Rate , Obesity , AnthropometryABSTRACT
Ageing is associated with an increase in Heart Rate Recovery (HRR). HRR is a property of vagal activity. But there is little evidence regarding the extent to which age-related changes in HRR depend on simultaneous transition from pre-menopausal state to postmenopausal state. The purpose of this study was (i) to compare HRR between pre and postmenopausal women, (ii) to compare heart rate recovery between men of age group 40-45 years and 45-50years respectively (iii) and to determine whether difference in age, gender and body composition could account for the difference in HRR between pre- and post-menopausal groups. Methods: HRR was assessed using modified Bruce exercise protocol. The body mass index was assessed by measuring weight and height of the subject. Data was analyzed after adjusting for age and body composition. Results: It was found that the HRR were significantly higher (P <0.001) in postmenopausal women compared to that of premenopausal women. Analysis after adjusting for age and gender revealed that men of same age group didn’t undergo much change in HRR as compared to women. Conclusions: The study concludes that both ageing and declined oestrogen levels are associated with the increased Hear Rate Recovery (HRR) seen among postmenopausal women.
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OBJECTIVE: To examine the association between cardiac performance during recovery and the severity of heart failure, as determined by clinical and cardiopulmonary exercise test responses. METHODS: As part of a retrospective cohort study, 46 heart failure patients and 13 normal subjects underwent cardiopulmonary exercise testing while cardiac output was measured using a noninvasive device. Cardiac output in recovery was expressed as the slope of a single exponential relationship between cardiac output and time; the recovery-time constant was assessed in relation to indices of cardiac function, along with clinical, functional, and cardiopulmonary exercise responses. RESULTS: The recovery time constant was delayed in patients with heart failure compared with normal subjects (296.7 + 238 vs. 110.1 +27 seconds, p <0.01), and the slope of the decline of cardiac output in recovery was steeper in normal subjects compared with heart failure patients (p,0.001). The slope of the decline in cardiac output recovery was inversely related to peak VO2 (r = -0.72, p<0.001) and directly related to the VE/VCO2 slope (r = 0.57, p,0.001). Heart failure patients with abnormal recovery time constants had lower peak VO2, lower VO2 at the ventilatory threshold, lower peak cardiac output, and a heightened VE/VCO2 slope during exercise. CONCLUSIONS: Impaired cardiac output recovery kinetics can identify heart failure patients with more severe disease, lower exercise capacity, and inefficient ventilation. Estimating cardiac output in recovery from exercise may provide added insight into the cardiovascular status of patients with heart failure.
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Humans , Middle Aged , Adaptation, Physiological/physiology , Cardiac Output/physiology , Exercise/physiology , Heart Failure/physiopathology , Epidemiologic Methods , Exercise Test/methods , Kinetics , Monitoring, Physiologic/methods , Oxygen Consumption/physiology , Time Factors , Thermodilution/methodsABSTRACT
Heart rate (HR) recovery after exercise is a function of vagal reactivation, and its impairment is a predictor of overall mortality and adverse cardiovascular events. While metabolic syndrome is associated with sympathetic overactivity, little is known about the relationship between metabolic syndrome and HR recovery. A symptom-limited exercise stress test in healthy subjects (n=1, 434) was used to evaluate HR recovery. Metabolic syndrome was defined according to the National Cholesterol Education Program's Adult Treatment Panel III (NCEP ATP-III) criteria. Seventeen percent of subjects had > or =3 criteria for metabolic syndrome. HR recovery was lower in men than women and in smokers than nonsmokers. The subject with metabolic syndrome (vs. without) showed lower HR recovery (10.3+/-11.6 vs. 13.6+/-9.7 per minute) and higher resting HR (64.3+/-10.3 vs. 61.6+/-9.1 per minute). HR recovery correlated inversely to age (r=-0.25, p<0.0001), but not to resting HR or maximal oxygen uptake. Delayed HR recovery was associated with metabolic syndrome after an adjustment for age, sex, resting HR and smoking (p<0.01). Metabolic syn-drome is associated with impaired vagal reactivation. Adverse cardiovascular out-comes associated with metabolic syndrome may be mediated by the failure of vagal reactivation in addition to sympathetic overactivity.
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Middle Aged , Male , Humans , Female , Adult , Walking/physiology , Smoking , Sex Factors , Oxygen Consumption/physiology , Metabolic Syndrome/blood , Heart Rate/physiology , Fasting/blood , Exercise/physiology , Cholesterol, HDL/blood , Body Mass Index , Blood Pressure/physiology , Blood Glucose/metabolism , Analysis of Variance , Age FactorsABSTRACT
BACKGROUND: The goal of this study is to evaluate the differences of the rate and the ratio of heart rate changes, which is well known to reflect the vagal reactivation, after peak exercise between ischemic heart disease and normal during treadmill exercise test. Additionally R-wave amplitude changes are evaluated to have the discriminal power between ischemic heart disease and normal. METHODS: We have studied 253 human (196 control, 57 patients) who took the symptom-limited exercise test using Marquette case 8000 model. The 57 patients who showed the positive result by exercise test have confirmed by coronary angiography. The rate of heart rate changes was defined as the absolute difference of the heart rate subtracted by the just-previous stage heart rate. The ratio of heart rate changes was defined as the percentile of the rate of heart rate changes comparing to the just-previous stage heart rate. The changes of R-wave amplitude at lead V5 and aVF were obtained by the subtraction of R-wave amplitude at the peak exercise stage from that at the standing rest stage respectively. Additively heart rate recovery was defined as the rate of heart rate change which was obtained at 1 minute later after peak exercise. RESULTS: In patients and control, the resting heart rate were 70 +/- 13 bpm and 69 +/- 11 bpm (p>0.05), and the peak heart rate were 136 +/- 22 bpm and 155 +/- 18 bpm respectively (p<0.001). The rate of heart rate changes in patients group were significantly lower than that in control at 1 minute, 3 minute, and 5 minute respectively (p<0.001, p=0.008, p=0.002). The ratio of heart rate changes in patients group were also significantly lower than that in control at 1 minute, 3 minute, and 5 minute respectively (p=0.017, p=0.027, p=0.002). With comparing both groups, the incidences of ventricular ectopy were not different during exercise and recovery stages, and the difference in the changes of R-wave amplitude at lead V5 and aVF were not observed respectively. CONCLUSION: The rate and ratio of heart rate changes are significantly lower in iscemic heart disease than in normal, and these are resulted from the depression of vagal reactivation. These findings are supplemental to make a diagnosis and a arrhythmic risk stratification of ischemic heart disease.
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Humans , Coronary Angiography , Depression , Diagnosis , Exercise Test , Heart Diseases , Heart Rate , Heart , Incidence , Myocardial IschemiaABSTRACT
@#ObjectiveTo explore the effect of outpatient cardiac rehabilitation on 40 patients with coronary artery disease (CAD) by evaluating heart rate recovery (HRR).Methods 40 CAD patients,31 males, 9 females, were performed by Effraim walk exercise program for 6 weeks and evaluated with method of heart rate recovery (H RR).ResultsThere were the significant differences in resting heart rate, peak heart rate achieved, and HRR after cardiac rehabilit ation.Conclusions Cardiac rehabilitation can impro ve HRR of patients with coronary artery disease.
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The time constants of beat-by-beat heart rate decay for the first 30 seconds (T30) after exercise is a specific index for the vagally mediated component of heart rate recovery. The aim of our study was to determine whether cardiac rehabilitation (CR) can accelerate T30 in patients after coronary artery bypass grafting (CABG) . Thirteen male patients who underwent CABG (aged 60.5±7.7years) were assigned to 7-21 day Phase I CR. Exercise training consisted of 30 minutes of aerobic exercise (bicycle ergometer) at the anaerobic threshold 2 times per day. T30 was measured as the heart rate decay regulated in patients who rested immediately after 5 minutes of pedaling exercise. After CR, T30 significantly improved from 413.3±129.7 to 300.1±124.5 sec (p<0.01) . Peak oxygen uptake (peak V02: 14.0±4.0 16.7±3.2mlin/kg: p<0.01) and heart rate at anaerobic threshold (HR @ AT: 111.9±13.4 103.6±11.7 beatsin: p<0.01) also improved significantly. There was no correlation between ΔT30 (Δ: difference before and after CR) and Δpeak VO<SUB>2</SUB>or ΔHR @ AT. These results suggest that CR for patients following CABG accelerates vagally mediated heart rate recovery after dynamic exercise.
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BACKGROUND: Propofol, a new intravenous anesthetic agent, is now used for brief operation and day surgery for its rapid recovery and controllability. Propofol, rapid acting sedatives hypnotics, is known to no analgesic effect. This study was taken to evaluate the analgesic effect of propofol, compared to those of fentanyl. METHODS: Forty patients (ASA physical status 1, 2) scheduled for surgery of short duration (within 1 hour) were randomly allocated into two groups. Induction of anesthesia was performed by injection of thiopental (5 mg/kg) and succinylcholine (1 mg/kg) and ventilated with O2-N2O (50%) after endotracheal intubation. Maintenance of anesthesia was performed by vecuronium (1 mg/kg) and continuous infusion of propofol (group I) or fentanyl (group II). RESULTS: There was no significant differences in systolic and diastolic blood pressure in both groups. In heart rate, there was significant difference at preincision and postincision between two groups. Time to extubation (4.5 +/- 4.6 vs 6.3 +/- 4.6 min), time to eye open (7.5 +/- 7.1 vs 6.6 +/- 5.4 min), time to complain pain after stop dropping at recovery room (30.5 +/- 8.0 vs 35.5 +/- 17.9 min), the average flow rate of drugs (6.0 +/- 2.2 mg/kg/hr vs 6.7 +/- 2.4 microgram/kg/hr) has no significant difference between two groups. CONCLUSIONS: A single continuous infusion of propofol is applied as one of general anesthesia methods with O2-N2O, muscle relaxants. Propofol has a appropriate and similar analgesic effect compared with fentanyl in operation of little hemodynamic changes and short operation, and rapid recovery compared with fentanyl.