Evening exercise did not hurt sleep in a 2026 trial. In a randomized cross-over study in Sleep Medicine, 31 adults aged 60 to 80 with insomnia symptoms did two weeks of coached activity in the morning and two in the evening. Insomnia scores matched, but morning activity moved the middle of sleep about 19 minutes earlier.
Key takeaways
- A randomized cross-over trial from Leiden University Medical Center, published in Sleep Medicine on 23 October 2026, compared morning (10 to 11 AM) and evening (7:30 to 8:30 PM) activity in older adults with insomnia symptoms.
- Sleep data came from 31 people with an average age of 69.8; each spent 14 days active in the morning and 14 days active in the evening.
- Insomnia severity did not differ between the morning and evening periods, and neither did self-rated sleep quality or the evening rise of melatonin.
- Sleep timing did shift: the midpoint of sleep came about 19 minutes earlier during the morning period than during the evening period.
- One change to make: choose the exercise time you can keep, put it in the morning if you want your sleep to drift earlier, and end hard sessions at least an hour before bed.
What did the 2026 exercise timing trial find?
Morning and evening activity worked about equally for insomnia symptoms, but morning activity nudged sleep earlier. A team led by Gali Albalak and Diana van Heemst at Leiden University Medical Center in the Netherlands ran the trial, called ON TIME, and published the results online on 23 October 2026 in Sleep Medicine.
| Study detail | What it was |
|---|---|
| Journal | Sleep Medicine, published online 23 October 2026 (open access) |
| Design | Randomized cross-over trial: each person tried every condition, in random order |
| People | Adults aged 60 to 80 with mild to clinical insomnia symptoms (Insomnia Severity Index of 10 or more); sleep data from 31 people, mean age 69.8, 64.5% women |
| Conditions | 14 days of coached activity from 10 to 11 AM, 14 days from 7:30 to 8:30 PM, and an inactive period |
| Sleep measures | Insomnia Severity Index, a sleep sensor under the mattress, a daily sleep-quality rating in a smartphone app, and saliva melatonin on the last day of each period |
| Insomnia score | No difference between morning and evening periods |
| Sleep timing | Midpoint of sleep about 19 minutes earlier during the morning period (3:54 vs 4:13 AM) |
The trial’s 2024 protocol in Trials describes outdoor sessions mixing endurance, strength and flexibility exercises.
Does exercising in the evening hurt your sleep?
Not in this trial, and not in most earlier research. Older adults who were active from 7:30 to 8:30 PM rated their sleep the same and had the same insomnia scores as when they were active in the morning.
That matches a 2019 meta-analysis of 23 studies of healthy adults in Sports Medicine by Jan Stutz, Raphael Eiholzer and Christina Spengler of ETH Zurich: a single evening workout did not worsen sleep, and slightly increased deep (slow-wave) sleep. The one caution: vigorous exercise ending within about 1 hour of bedtime might delay sleep and shorten it.
Why did morning activity shift sleep earlier?
The trial did not pin down why. The authors measured dim light melatonin onset, the evening rise of melatonin that marks the body clock’s timing, and found no difference between the two periods, so the 19-minute shift appeared in measured sleep timing but not in that hormone marker.
One plausible piece is daylight: the trial’s protocol planned outdoor sessions, so morning activity likely came with late-morning light, while evening sessions could fall at dusk or after dark depending on the season. Light and activity both set the body clock’s timing, and this trial was not designed to separate them.
Did exercise improve insomnia at all?
Insomnia scores fell in every period, including the inactive one, so the trial cannot show that the activity itself caused the improvement. The average score was 14.4 at the start, 12.4 after the inactive period, 11.9 after the morning period and 12.4 after the evening period.
Simply joining a study and tracking sleep each day may help. Physical activity still has broad support: the World Health Organization lists improved sleep among its benefits for adults and older adults and recommends at least 150 minutes of moderate-intensity activity a week.
What are the limits of the study?
This was a small trial, with sleep data from 31 people and two-week activity periods. Everyone was 60 to 80 and had insomnia symptoms, so the results may not apply to younger adults, shift workers or good sleepers, and coached activity is not the same as exercising alone. The authors call for larger studies to define the best, and personal, timing of activity for sleep.
What is the one change to make?
Schedule movement at a time you can keep, and use the clock to steer sleep timing. This is an everyday habit, not a treatment for insomnia; ongoing sleep problems deserve a conversation with a clinician.
- Pick a daily movement slot you can hold most days. In this trial, morning and evening worked about equally for insomnia symptoms.
- If your sleep runs later than you would like, try a late-morning slot, outdoors when you can, as the trial’s protocol planned for its 10 to 11 AM sessions.
- If evenings are your only free time, keep them. Finish hard workouts at least an hour before bed and leave gentle stretching for the last stretch of the evening.
For the strength side of the timing question, read Best Time to Exercise? What a 2026 Trial Found. If your sleep has drifted late, How to Fix Your Sleep Schedule: Anchor, Light, 15 Min lays out a reset, and Irregular Sleep and Death Risk: What a 2026 Study Found explains why steady timing matters. Curious when your own body clock runs best? Take the Body Clock Type quiz.
Your day on My BodyClock
The day above on My BodyClock puts movement where this trial found it nudged sleep earlier. After waking at 6:30 AM and an unhurried breakfast, focused work fills the early morning, then a 10 to 11 AM block of outdoor movement mirrors the trial’s morning sessions: a brisk walk, some strength work and stretching in daylight. Work resumes until mid-afternoon, with lunch in between. The evening is for people and a home-cooked dinner, then an hour of calm wind-down, with no hard exercise in the last hour, before 8 hours of sleep from 10:30 PM.
Evenings your only free window? Swap the 10 AM block for an early-evening session. Build your own version in Owaves: My BodyClock on the App Store, or join the Android waitlist.
FAQ
Is it bad to exercise in the evening?
Not for most people. In a 2026 trial of older adults with insomnia symptoms, activity from 7:30 to 8:30 PM led to the same insomnia scores and sleep ratings as morning activity. A 2019 review of 23 studies agreed, with one caution about vigorous exercise close to bedtime.
Is morning or evening exercise better for sleep?
In the 2026 Leiden trial, neither was better for insomnia symptoms or self-rated sleep quality. Morning activity did move the midpoint of sleep about 19 minutes earlier, so the morning may suit people who want to fall asleep and wake earlier.
How long before bed should you stop exercising?
At least about an hour for vigorous exercise. The 2019 Sports Medicine meta-analysis found that hard exercise ending within 1 hour of bedtime might lengthen the time to fall asleep and shorten sleep; that caution applied to vigorous exercise, not to gentle stretching or an easy walk.
Does exercise help insomnia in older adults?
It may, but this trial could not prove it, because insomnia scores also improved in the inactive period. Regular activity is still linked with better sleep, and the World Health Organization recommends at least 150 minutes of moderate activity a week.
Sources
- Albalak G, Noordam R, van der Elst M, Drop T, Caneda Cabrera E, Oudendijk L, Lammers GJ, Gordijn M, Kervezee L, Exadaktylos V, van Bodegom D, van Heemst D. The effect of physical activity timing on insomnia and sleep quality: a randomized cross-over trial in older adults. Sleep Medicine, published online 23 October 2026;149:109332. doi:10.1016/j.sleep.2026.109332. https://pubmed.ncbi.nlm.nih.gov/42945713/
- Albalak G, Noordam R, van der Elst M, Kervezee L, Exadaktylos V, van Bodegom D, van Heemst D. Older adults exercising ON TIME: protocol for a randomized controlled cross-over study to assess the effect of physical activity timing on insomnia severity. Trials, 5 August 2024;25(1):523. doi:10.1186/s13063-024-08310-7. https://pmc.ncbi.nlm.nih.gov/articles/PMC11299269/
- Stutz J, Eiholzer R, Spengler CM. Effects of Evening Exercise on Sleep in Healthy Participants: A Systematic Review and Meta-Analysis. Sports Medicine, 2019;49(2):269-287. doi:10.1007/s40279-018-1015-0. https://pubmed.ncbi.nlm.nih.gov/30374942/
- World Health Organization. Physical activity (fact sheet). https://www.who.int/news-room/fact-sheets/detail/physical-activity
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