Heart rate recovery after exercise: relations to heart rate variability and complexity.
This investigation was carried out to study the relationship between resting heart rate variability (HRV) and heart rate recovery (HRR) after upper body exercise test (arm cranking) in some healthy men with different ages. Thirty-six healthy men (children n = 12, adult n = 12, elderly n = 12) performed an incremental upper body exercise testing on an arm ergometer. HRV was obtained via an ECG during rest. HRR was reported as the reduction in heart rate from the peak exercise to the heart rate 2 min after cessation of exercise. In children, resting standard deviation of normal RR intervals (SDNN) and root mean square of sequential deviations (RMSSD) were significantly correlated with heart rate recovery two min after cessation of exercise (r = 0.809, P = 0.003 and r = 0.719, P = 0.13, respectively). In contrast, there was no significant relationship between resting HRV parameters and HRR2 in the adult and elderly groups. The results of this investigation suggested that in children HRR2 in early stages after upper body exercise was related to basal parasympathetic modulation. Further studies are needed to identify and document the effect of various physical activities on autonomic cardiovascular health in different ages.