title: Effects of moderate and heavy endurance exercise on nocturnal HRV.
abstract: 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.
authors.affiliation: KIHU-Research Institute for Olympic Sports, Sports Physiology, Jyväskylä, Finland. esa.hynynen@kihu.fi
authors.forename: E
authors.initials: E
authors.lastname: Hynynen
authors.forename: V
authors.initials: V
authors.lastname: Vesterinen
authors.forename: H
authors.initials: H
authors.lastname: Rusko
authors.forename: A
authors.initials: A
authors.lastname: Nummela
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D012420:Running / Q000502:physiology