Post-exercise cardiac autonomic recovery is associated with resting chronotropic response in different body positions in men

Aim: This study evaluated the association between heart rate recovery (HRR) and cardiac parasympathetic reactivation following a submaximal exercise test with resting heart rate (RHR) in the supine and orthostatic positions. Methods: The heart rate (HR), HRR, relative HRR (Δ% HRR), and cardiac parasympathetic reactivation (r-MSSD) values during passive orthostatic recovery at the 1st, 3rd, and 5th min following the submaximal exercise test were correlated with RHR in both the supine (RHRsup) and orthostatic (RHRort) positions in 24 physically active men. The statistical analysis employed Pearson and Spearman correlation tests with a two-tailed p-value set at ≤ 0.05. Results: At the 1st min, HR was significantly correlated with RHRort (r = 0.40; p = 0.05). HR, HRR, and Δ% HRR at the 3rd and 5th min were significantly correlated with RHR (r = from -0.67 to 0.73; p ≤ 0.02; R2 = 32-53%), independent of the body position at rest. At the 3rd and 5th min, the r-MSSD was significantly correlated with RHRsup (r = -0.60, -0.46; p ≤ 0.02). At the 3rd min, the r-MSSD was significantly correlated with RHRort (r = -0.46; p = 0.02). Conclusion: Faster HRR and parasympathetic reactivation on the 3rd and 5th minute after the submaximal exercise test were associated with low RHR in the supine and orthostatic positions in active young men.