No time of day has been shown to build strength best. In a randomized trial of 108 adults aged 60 to 80, published 25 September 2026, people who trained for 12 weeks at their strongest hour gained about the same as those training at their weakest. The one change: pick a workout time you can keep.
Key takeaways
- In a randomized trial of 108 adults aged 60 to 80 (Journal of Cachexia, Sarcopenia and Muscle, 25 September 2026), 12 weeks of training at each person’s strongest hour built about the same strength and lean mass as training at their weakest hour.
- In a second 2026 trial, untrained women aged 18 to 50 with obesity got stronger and fitter whether they trained from 7 to 10 AM or from 6 to 9 PM (Frontiers in Sports and Active Living).
- Among 375 people who had kept off lost weight, 86.3% of consistent-time exercisers met the 150-minute weekly guideline, versus 74.2% of those whose timing varied (Obesity, 2019).
- The change to make: choose one workout slot you can keep, and put it on My BodyClock.
Is there a best time of day to exercise?
Not for building strength and fitness, on current evidence. A 2023 meta-analysis in Sports Medicine – Open reviewed 26 training studies and found little evidence for or against any time of day, and rated most of those studies at high risk of bias.
Your performance does follow a daily rhythm. In the 2026 trial below, volunteers tested strongest most often in the afternoon (32%) or evening (33%). Strength swung about 11% across the day on average. But a daily swing in strength is not the same as a difference in how much you improve over weeks.
What did the 2026 trial in adults aged 60 to 80 find?
Training at your personal best hour did not add strength or muscle. Researchers at the University of Basel, working with Frank Scheer of Brigham and Women’s Hospital and Harvard Medical School, tested each volunteer’s strength at 8 AM, noon, 4 PM and 8 PM on four separate days to find that person’s peak and trough. They then randomly assigned 108 healthy adults (average age 67, 41% women) to train at their peak, train at their trough, or keep their usual routine.
Training lasted 12 weeks: two supervised full-body strength sessions and one 30-minute moderate cycling session a week. Neither participants nor trainers knew who had been placed at their peak or trough, and 93 people were included in the analysis.
For the primary outcome, a maximal pull from mid-thigh height, the peak-versus-trough difference was 0.06 newtons per kilogram of body weight (95% confidence interval −0.76 to 0.88). Grip strength and lean mass followed the same pattern, and the four training times showed no consistent differences. Even the gaps between training and not training were small on these measures. Attendance was 91% and 93% of strength sessions, and no serious adverse events were linked to the training.
The authors concluded that strength training works across different times of day in older adults, supporting flexible scheduling to help people stick with it. Limits: one center, healthy and independent volunteers, and each peak estimated from a single four-day profile, so the results may not apply to frail adults.
Does morning or evening exercise work better for younger adults?
A smaller 2026 trial points the same way. Researchers in Brazil randomly assigned previously untrained women aged 18 to 50 with obesity to train in the morning (7 to 10 AM, 17 women), the evening (6 to 9 PM, 19 women), or not at all (13 women), with 8 weeks of combined strength and aerobic sessions three times a week.
Both training groups got stronger, with bench-press maximums up about 5 to 6 kilograms, and aerobic fitness improved. The study, published 15 September 2026 in Frontiers in Sports and Active Living, found no consistent advantage for either time. It is a small study.
Why does a consistent workout time help?
A regular slot is linked with doing more exercise, whatever the hour. In a 2019 survey in Obesity, 68.0% of 375 National Weight Control Registry members, people who had lost weight and kept it off, reported exercising at a consistent time of day, and 86.3% of them met the 150-minute weekly guideline, versus 74.2% of people whose timing varied. The amount did not differ by which time they chose, and steady cues, such as the same location, went with more activity.
A study published 28 September 2026 in Medicine & Science in Sports & Exercise adds a population view. Among 3,153 US adults who wore activity monitors in the 2003–2006 National Health and Nutrition Examination Survey, people who did most of their moderate-to-vigorous activity between 6 and 10 AM were about 1.5 times as likely to meet activity guidelines as people whose activity was spread across the day.
Both studies are observational, so they show associations, not cause. But when the hour makes little difference to gains, the hour you reliably show up for counts most.
When does the time of day still matter?
It may matter when you train for an event at a set time. The 2023 meta-analysis found some evidence of larger performance gains when training and testing happened at the same time of day, though the 2026 trial saw no consistent benefit. Still, if your race starts early, practice early.
Otherwise, let your week decide. For how athletes fit training into a day, read Laird Hamilton’s Daily Routine and Eliud Kipchoge’s Daily Routine. Student-athletes can see our survey in More Than 1 in 3 College Athletes Lost Time to Fatigue Last Season.
How do you pick a workout time you will keep?
Choose the slot that survives a normal week.
- Find one time that is free on most training days: before work, at lunch or after work.
- Add it to My BodyClock as a Move block with the same start time each training day.
- Keep the cues steady: the same place, the same bag, the same warm-up.
- If the slot keeps getting bumped, move the slot, not the habit.
Your Body Clock Type can hint at your easiest slot: take the Body Clock Type quiz. This is general education, not medical advice; if you are new to strength training or have a health condition, check with a clinician first.
Your day on My BodyClock
The day above on My BodyClock shows the one change in practice. A short walk soon after waking gets you moving, and a 5:30 PM strength session holds the same slot on every training day, with travel on either side planned as Flow. The gym bag gets packed before wind-down.
Swap in your own slot — morning, midday or evening — as long as you can keep it. Build your version in Owaves: My BodyClock on the App Store, or join the Android waitlist.
FAQ
Is it better to work out in the morning or the evening?
Neither has been shown to be better for building strength or fitness. In a 2026 trial, women with obesity who trained from 7 to 10 AM or from 6 to 9 PM both got stronger and fitter over 8 weeks, and a 2026 trial in adults aged 60 to 80 found no consistent differences among 8 AM, noon, 4 PM and 8 PM.
Does working out at the same time every day matter?
It is linked with doing more. In a 2019 study of 375 people who had kept off lost weight, 86.3% of consistent-time exercisers met the 150-minutes-a-week guideline, versus 74.2% of those whose timing varied. That is an association, not proof of cause.
Should older adults lift weights at a certain time of day?
A 2026 trial suggests timing matters little. Adults aged 60 to 80 who trained at the hour they tested strongest gained about the same strength and lean mass as those who trained at their weakest hour.
Sources
- Bruggisser F, et al. Effects of Daily Rhythm-Aligned Training on Skeletal Muscle Adaptation in Older Adults: A Randomized Controlled Trial. Journal of Cachexia, Sarcopenia and Muscle, 25 September 2026. https://pmc.ncbi.nlm.nih.gov/articles/PMC13614912/
- Vieira YLM, et al. Morning or evening? Time of day does not affect body composition, cardiopulmonary performance, and muscle strength responses to combined training in women with obesity. Frontiers in Sports and Active Living, 15 September 2026. https://pubmed.ncbi.nlm.nih.gov/42812561/
- Zhang K, et al. Timing of Device-Measured Physical Activity and Sleep in Relation to Meeting Physical Activity Guidelines in U.S. Adults. Medicine & Science in Sports & Exercise, 28 September 2026. https://pubmed.ncbi.nlm.nih.gov/42804660/
- Bruggisser F, et al. Best Time of Day for Strength and Endurance Training to Improve Health and Performance? A Systematic Review with Meta-analysis. Sports Medicine – Open, 19 May 2023. https://pubmed.ncbi.nlm.nih.gov/37208462/
- Schumacher LM, et al. Relationship of Consistency in Timing of Exercise Performance and Exercise Levels Among Successful Weight Loss Maintainers. Obesity, August 2019. https://pubmed.ncbi.nlm.nih.gov/31267674/
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