Post-exercise heart rate recovery and parasympathetic reactivation are comparable between prepubertal boys and well-trained adult male endurance athletes

Purpose This study tested the hypothesis that prepubertal boys, but not untrained men, would exhibit a similar post-exercise parasympathetic reactivation as well-trained adult male endurance athletes. Methods Twelve prepubertal boys (12.3 ± 1.6 years), 14 untrained men (21.8 ± 2.2 years) and 16 well-trained adult male endurance athletes (24.5 ± 4.8 years) completed an incremental maximal run field test on a track. Immediately after exercise completion, heart rate recovery (HRR) was assessed in the supine position for 5 min. Heart rate variability was analyzed in the time domain, and log-transformed values of the root mean square of successive differences in heart beats (Ln RMSSD 30 ) were calculated over consecutive 30 s windows. Results Prepubertal children and well-trained adult endurance athletes showed significantly faster HRR than untrained adults from 30 s post-exercise until the end of recovery ( p