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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Body Temperature, Case-Control Studies, Exercise, Heart Rate, Humans, Male, Sleep, REM, Time Factors, Young Adult.
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Is sleep onset disrupted following pre-sleep exercise that causes large physiological excitement at bedtime? Context: 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. 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. 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.
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These results indicate that pre-sleep vigorous exercise, which causes a large physiologic excitement at bedtime, might disrupt the onset of sleep. Final Decision: yes