Moderate endurance exercise and marathon running increased nocturnal heart rate to 109% and 130% of baseline, respectively, and decreased HRV parameters, indicating prolonged autonomic modulation.
Does moderate and heavy endurance exercise alter nocturnal heart rate variability in healthy, physically active men?
Endurance exercise induces a dose-dependent disturbance in nocturnal autonomic modulation, characterized by increased heart rate and decreased heart rate variability.
This study examined the effects of endurance exercise on nocturnal autonomic modulation. Nocturnal R-R intervals were collected after a rest day, after a moderate endurance exercise and after a marathon run in ten healthy, physically active men. Heart rate variability (HRV) was analyzed as a continuous four-hour period starting 30 min after going to bed for sleep. In relation to average nocturnal heart rate after rest day, increases to 109+/-6% and 130+/-11% of baseline were found after moderate endurance exercise and marathon, respectively. Standard deviation of R-R intervals decreased to 90+/-9% and 64+/-10%, root-mean-square of differences between adjacent R-R intervals to 87+/-10% and 55+/-16%, and high frequency power to 77+/-19% and 34+/-19% of baseline after moderate endurance exercise and marathon, respectively. Also nocturnal low frequency power decreased to 56+/-26% of baseline after the marathon. Changes in nocturnal heart rate and HRV suggest prolonged dose-response effects on autonomic modulation after exercises, which may give useful information on the extent of exercise-induced nocturnal autonomic modulation and disturbance to the homeostasis.
Hynynen et al. (2010) studied Healthy (n=10). Moderate endurance exercise and marathon run vs. Rest day was evaluated on Nocturnal autonomic modulation (heart rate and heart rate variability). Moderate endurance exercise and marathon running increased nocturnal heart rate to 109% and 130% of baseline, respectively, and decreased HRV parameters, indicating prolonged autonomic modulation.