Effects of morning versus evening exercise on sleep: a systematic review of comparative studies with a meta-analysis of randomized controlled trials
Study Details
This new meta-analysis compiled data from 25 studies (4,233 adults) comparing morning versus evening/nighttime exercise 🔍
Here are the key findings ⬇️
Key Findings
⏰ Overall, exercise timing had only modest effects on sleep, with no clear advantage of morning exercise for most outcomes
😴 Total sleep time did not differ between morning and evening exercise
🛏️ Time in bed was also similar regardless of exercise timing
💤 Sleep efficiency showed no significant overall difference between morning and evening exercise
⏱️ Sleep onset latency was unaffected, suggesting evening exercise did not generally make it harder to fall asleep
🌙 Self-reported sleep quality was also similar between morning and evening exercise
👀 Wake after sleep onset (WASO) was the notable exception, with evening/nighttime exercise associated with moderately greater wakefulness during the night
📊 The WASO effect was SMD = −0.51, although evidence certainty was very low and potential small-study effects were identified
🔥 Exercise intensity appeared to influence the relationship between timing and sleep
⚡ Moderate-to-vigorous evening exercise was more likely to impair sleep continuity than low-intensity exercise
📈 At moderate intensity, evening exercise was associated with greater WASO, while the largest effect at high intensity came from only one study
🏃 Acute versus repeated exercise did not clearly alter the effect of exercise timing on sleep
🩺 Health status and habitual activity level also did not meaningfully modify the findings
🧠 Chronotype may influence individual responses, but it was reported in too few studies to properly analyse
🌅 Morning exercise may advance circadian timing, while evening exercise may delay it, although evidence for the practical importance of this remains limited
⏳ The interval between exercise and bedtime may ultimately matter more than clock time alone
Conclusion
Exercise timing can therefore remain flexible, prioritising adherence and preference, while allowing sufficient recovery (~4hrs) before sleep after harder evening sessions ✅
Reference
https://pubmed.ncbi.nlm.nih.gov/42632303/
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