title: Sleep onset is disrupted following pre-sleep exercise that causes large physiological excitement at bedtime.
abstract: OBJECTIVE
  Many studies have failed to show that pre-sleep exercise has a negative effect on sleep onset. However, since only a moderate level of physiological excitement was observed at bedtime in these studies, it remains unclear whether a larger magnitude of physiologic excitement present at bedtime would disrupt sleep onset. This study compared the effects of pre-sleep exercise, which led to different levels of physiologic excitement at bedtime (moderate and heavy), on sleep onset.
  
  
  METHODS
  Twelve active young men underwent non-exercise, moderate-intensity exercise, and high-intensity exercise conditions. The subjects maintained a sedentary condition on a reclining seat throughout the day. On the non-exercise day, the subjects remained seated at rest until going to bed. On the moderate- and high-intensity exercise days, the subject exercised for 40 min (21:20-22:00) at 60 and 80% heart rate reserve, respectively. Sleep polysomnography, core body and skin temperatures, heart rate (HR), and heart rate variability (HRV) were recorded.
  
  
  RESULTS
  We observed a delay in sleep onset (+14.0 min, P < 0.05), a marked physiological excitement at bedtime as reflected by an increased HR (+25.7 bpm, P < 0.01), and a lower high-frequency power of HRV (-590 ms(2), P < 0.01) only on the high-intensity exercise day.
  
  
  CONCLUSIONS
  These results indicate that pre-sleep vigorous exercise, which causes a large physiologic excitement at bedtime, might disrupt the onset of sleep.
authors.affiliation: Department of Sport Education, School of Lifelong Sport, Hokusho University, 23 Bunkyodai, Ebetsu, Hokkaido, 069-8511, Japan, os@hokusho-u.ac.jp.
authors.forename: Shiro
authors.initials: S
authors.lastname: Oda
authors.forename: Kazuki
authors.initials: K
authors.lastname: Shirakawa
mesh_terms: D001831:Body Temperature; D016022:Case-Control Studies; D015444:Exercise; D006339:Heart Rate; D006801:Humans; D008297:Male; D012895:Sleep, REM / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult