Does high-intensity exercise lead to worse sleep? Original paper

This meta-analysis found that high-intensity exercise in the evening disrupted REM sleep but not other objective measures of sleep quality in healthy people without sleep disorders.

This Study Summary was published on October 3, 2021.

Background

Current sleep hygiene recommendations suggest that exercising near bedtime may disrupt normal circadian rhythms,[1] but the evidence is mixed. Some trials exploring the effects of evening high-intensity exercise (HIE) found that HIE had no effect on sleep,[2][3] others that it might improve it,[4] and yet others that it might impair it.[5] Some variables at play may be exercise duration, light exposure (from the sun or artificial lights, during exercise), and the fitness level, muscle soreness, and sleep-hygiene practices of each individual.[6]

The study

This study was a meta-analysis of 15 randomized controlled trials that compared either habitual evening HIE or a single bout of evening HIE to no exercise. The 194 participants were healthy and had good sleep quality; 69% of them were fit and active.

Sleep quality was measured either objectively, via polysomnography and actigraphy, or subjectively, via standardized questionnaires. The primary outcomes were total sleep time (TST), time in bed (TIB), sleep efficiency (SE), sleep onset latency (SOL), wake time after sleep onset (WASO), and sleep architecture. The secondary outcome was subjective sleep quality.

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The results

HIE a half-hour to 4 hours before bed decreased REM sleep (−2.34%) without affecting the other objective measures of sleep quality. Additionally, it either did not affect subjective sleep quality or trended toward slightly worsening it (p = 0.05; 95% CI: −0.67, 0.00).

A subgroup analysis looked at the timing and intensity of exercise before sleep. Here are its findings:

  • HIE between 4 and 8 p.m. decreased SOL (−4.6 minutes) and REM sleep (−1.9%). The time separating exercise and bedtime doesn’t seem to have been taken into account here.
  • HIE 2 hours before bed increased TST and decreased SOL.
  • HIE performed at 65–80% of maximal capacity decreased REM sleep, whereas HIE performed at more than 80% of maximal capacity increased N3 sleep (an NREM stage of deep sleep and increased delta brainwave activity).
  • HIE decreased SOL and REM sleep in habitually sedentary participants, and it increased REM sleep latency in physically fit participants.
  • Longer HIE (30 to 60 minutes) increased TST and decreased SOL and percentage of REM sleep, whereas shorter HIE (25 to 30 minutes) did not affect any of the sleep parameters.
  • Running increased REM sleep latency, whereas cycling increased N3 sleep and decreased SOL and percentage of REM sleep.

Note

There are some limitations to this analysis. The studies included were predominantly in physically active, healthy young men without sleep disorders. In participants with sleep disorder, exercise might have brought the sleep improvements seen in other studies.[8][9] [10][11][12][13] Further research is needed to see if the findings of the present meta-alaysis also apply to women, older people, and people with impaired sleep.

Another trial published earlier this year and summarized here found that acute, nighttime, moderate exercise didn’t affect sleep in people with diagnosed insomnia, overall, though two of the participants did experience worsened sleep.[1]

The big picture: Various external factors influence circadian rhythms. These factors, called zeitgebers, include not only exercise but also light, noise, temperature, meal timing, and more.

When it comes to exercise (as a zeitgeber), consistency trumps timing. If you’re used to working out at a particular time of day, changing that routine can disrupt your circadian rhythm, ultimately upsetting your sleep cycle. Transitioning into sleep is accompanied by a drop in body temperature, though, so if someone were to work up a sweat immediately before bed, that could theoretically disrupt their sleep.[14]

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This Study Summary was published on October 3, 2021.

References

  1. ^Shawn D Youngstedt, Wakako Ito, Giselle Soares Passos, Marcos Gonçalves Santana, Julia M YoungstedtTesting the sleep hygiene recommendation against nighttime exerciseSleep Breath.(2021 Jan 10)
  2. ^Penelope Larsen, Frank Marino, Kerri Melehan, Kym J Guelfi, Rob Duffield, Melissa SkeinEvening high-intensity interval exercise does not disrupt sleep or alter energy intake despite changes in acylated ghrelin in middle-aged menExp Physiol.(2019 Jun)
  3. ^Tero Myllymäki, Heikki Kyröläinen, Katri Savolainen, Laura Hokka, Riikka Jakonen, Tanja Juuti, Kaisu Martinmäki, Jukka Kaartinen, Marja-Liisa Kinnunen, Heikki RuskoEffects of vigorous late-night exercise on sleep quality and cardiac autonomic activityJ Sleep Res.(2011 Mar)
  4. ^Craig Thomas, Helen Jones, Craig Whitworth-Turner, Julien LouisHigh-intensity exercise in the evening does not disrupt sleep in endurance runnersEur J Appl Physiol.(2020 Feb)
  5. ^Matteo Bonato, Antonio La Torre, Ivana Marventano, Marina Saresella, Giampiero Merati, Giuseppe Banfi, Jacopo A VitaleEffect of High-Intensity Interval Training Versus Small-Sided Games Training on Sleep and Salivary Cortisol LevelInt J Sports Physiol Perform.(2020 Sep 1)
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  8. ^Kovacevic A, Mavros Y, Heisz JJ, Fiatarone Singh MAThe effect of resistance exercise on sleep: A systematic review of randomized controlled trialsSleep Med Rev.(2018 Jun)
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  10. ^Wang F, Eun-Kyoung Lee O, Feng F, Vitiello MV, Wang W, Benson H, Fricchione GL, Denninger JWThe effect of meditative movement on sleep quality: A systematic reviewSleep Med Rev.(2016 Dec)
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  14. ^Edward C Harding, Nicholas P Franks, William WisdenThe Temperature Dependence of SleepFront Neurosci.(2019 Apr 24)