The effects of exercise time-of-day on sleep architecture

Le résumé fourni par la source

Many adults remain physically inactive, despite the benefits of exercise for sleep. Methods to improve exercise compliance may include preferential time-of-day or engage in short-duration, high-intensity exercise (HIE), which has many health benefits including weight loss and increased cardiovascular fitness. However, when performed close to bedtime, it may reduce rapid eye movement (REM) sleep. Adequate sleep architecture may be more beneficial for the health of middle-aged adults, due to increased risk of disease with aging, rather than delaying or disrupting sleep to engage in exercise. Hence, the aim of this study was to investigate the effect of exercise time-of-day in middle-aged men on sleep architecture. 11 inactive men (age: 49±4.6y) completed 3 exercise trials of high-intensity interval cycling in a randomised order (60s at 100% VO2peak: 240s at 50% VO2peak) in the morning (MORN; 0600-0700h), afternoon (AFT; 1400-1600h), and evening (EVEN; 1900-2000h). Participants were screened for sleep disorders using questionnaires and 2 nights type 2 polysomnography (PSG). The sleep studies were further used to determine baseline sleep parameters. Participants’ sleep was monitored using PSG the night following each exercise trial and scored for time in bed, total sleep time, sleep efficiency, sleep onset latency, REM onset latency, wake after sleep onset, and sleep stages (N1, N2, N3, and REM) for the whole night and initial 3h after sleep onset. Percent N3 sleep was greater following MORN (22.9±7.3%) compared to baseline (18.0±7.2%; p=0.02) with no other sleep-related differences. For the Initial 3h of sleep, percent of NREM sleep (92.4±5.1%) was greater and REM sleep (7.7±5.1%) was reduced following EVEN compared to baseline (87.3±5.4%; p=0.01). Sleep quantity does not appear to be influenced by HIE regardless of exercise time-of-day. However, when HIE is performed close to bedtime, sleep quality is reduced in the initial 3h, as indicated by decreased time spent in REM sleep.

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