Abstract:-The aim of this study was to evaluate the relationship between vagal withdrawal and reactivation indices and maximal running velocity (Vmax) ) performed a graded exercise test until exhaustion, with the last complete stage performed corresponding to Vmax. Heart rate variability (HRV) parameters were calculated at 1-minute intervals until 85% of maximum HR and plotted against time for the estimation of vagal withdrawal indices (τ, amplitude (A) and area under the curve (AUC)). Vagal reactivation indices were… Show more
“…It appears that both methods of HRV quantification yield similarly reproducible indices of HRV during exercise. We thought that the time domain parameters would demonstrate a greater reproducibility as these are suggested to be less influenced by non-stationarities in the data (Pagani et al 1988, Perandini et al 2009, Asmussen and Kristiansson 1968). However, it must be noted that quantification of HRV in the frequency-domain requires pre-processing to improve the stability of the RR timeseries, and this might conceivably have improved the repeatability of the frequency-domain HRV measures.…”
The use of heart rate variability (HRV) parameters during exercise is not supported by appropriate reliability studies. In 80 healthy adults, ECG was recorded during three 6 min bouts of exercise, separated by 6 min of unloaded cycling. Two bouts were at a moderate intensity while the final bout was at a heavy exercise intensity. This protocol was repeated under the same conditions on three occasions, with a controlled start time (pre-determined at the first visit). Standard time and frequency domain indices of HRV were derived. Reliability was assessed by Bland–Altman plots, 95% limits of agreement and intraclass correlation coefficients (ICC). The sample size required to detect a mean difference ≥30% of the between-subject standard deviation was also estimated. There was no systematic change between days. All HRV parameters demonstrated a high degree of reproducibility during baseline (ICC range: 0.58–0.75), moderate (ICC: 0.58–0.85) and heavy intensity exercise (ICC range: 0.40–0.76). The reproducibility was slightly diminished during heavy intensity exercise relative to both unloaded baseline cycling and moderate exercise. This study indicates that HRV parameters can be reliably determined during exercise, and it underlines the importance of standardizing exercise intensity with regard to fitness levels if HRV is to be reliably determined.
“…It appears that both methods of HRV quantification yield similarly reproducible indices of HRV during exercise. We thought that the time domain parameters would demonstrate a greater reproducibility as these are suggested to be less influenced by non-stationarities in the data (Pagani et al 1988, Perandini et al 2009, Asmussen and Kristiansson 1968). However, it must be noted that quantification of HRV in the frequency-domain requires pre-processing to improve the stability of the RR timeseries, and this might conceivably have improved the repeatability of the frequency-domain HRV measures.…”
The use of heart rate variability (HRV) parameters during exercise is not supported by appropriate reliability studies. In 80 healthy adults, ECG was recorded during three 6 min bouts of exercise, separated by 6 min of unloaded cycling. Two bouts were at a moderate intensity while the final bout was at a heavy exercise intensity. This protocol was repeated under the same conditions on three occasions, with a controlled start time (pre-determined at the first visit). Standard time and frequency domain indices of HRV were derived. Reliability was assessed by Bland–Altman plots, 95% limits of agreement and intraclass correlation coefficients (ICC). The sample size required to detect a mean difference ≥30% of the between-subject standard deviation was also estimated. There was no systematic change between days. All HRV parameters demonstrated a high degree of reproducibility during baseline (ICC range: 0.58–0.75), moderate (ICC: 0.58–0.85) and heavy intensity exercise (ICC range: 0.40–0.76). The reproducibility was slightly diminished during heavy intensity exercise relative to both unloaded baseline cycling and moderate exercise. This study indicates that HRV parameters can be reliably determined during exercise, and it underlines the importance of standardizing exercise intensity with regard to fitness levels if HRV is to be reliably determined.
“…In the present study, the faster HRR found in the first (HRR60s) and second (HRR120s) minutes after constant load exercise suggests that the beginning of passive recovery is also influenced by withdrawal of sympathetic activity (Danieli et al., 2014). The RMSSD 30s , a non‐stationary HRV index representing vagal modulation, was higher for some minutes after the constant workload exercise (Perandini et al., 2010). In addition, the higher value observed at 120 s may be related to the higher decay of heart rate at the same time in constant workload exercise.…”
The main purpose of this study was to compare the effect of the constant load and self-paced exercise with similar total work on autonomic control after endurance exercise. Ten physically active men were submitted to (i) a maximal incremental exercise test, (ii) a 4-km cycling time trial (4-km TT), and (iii) a constant workload test with identical total external work performed at 4-km TT. Gas exchange was measured throughout the tests, while blood lactate, heart rate, and heart rate variability (HRV) were measured during the passive recovery. Power output measured at the last lap (i.e. 3600-4000 m) of 4-km TT (316 ± 89 W) was statistically higher than power output measured at the end of the constant workload exercise (211 ± 42 W). The 4-km TT produced higher values of blood lactate concentration (8.8 ± 2.1 mmol L) than the constant workload test (7.8 ± 2.1 mmol L). The heart rate recovery measured at 60 s (constant workload: 37 ± 7 bpm; 4-km TT: 30 ± 6) and 120 s (constant workload: 57 ± 9 bpm; 4-km TT: 51 ± 9 bpm) were higher in the constant workload than in the self-paced exercise. The HRV (i.e. RMSSD30s) was statistically higher in the constant load exercise measured at 120, 420, 450, 480, 540, and 570 s than the self-paced exercise. These findings suggest that the autonomic control responses were dependent of the endurance exercise modalities, with parasympathetic activity being delayed after self-paced exercise, as evidenced by post-exercise heart rate indices.
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