Starting a regular workout habit was linked to 37% higher odds of waking up feeling rested a year later, in a study of 702,007 Japanese adults. Just being busy on your feet all day? That showed no consistent link at all.
The findings, published in Medicine & Science in Sports & Exercise, the journal of the American College of Sports Medicine, add big-data weight to an idea sleep experts have pushed for years: exercise for better sleep works best when it’s deliberate. Here’s what the researchers found, what the study can’t prove, and a simple plan to test it on your own nights.
The 702,007-Person Study, in Plain English
The study was led by H. Miyagi, with co-authors H. Fukuda and K. Yamamoto. The team tracked Japanese adults who completed annual health checkups in two back-to-back years, 2021 and 2022.
That setup is the clever part. Instead of taking one snapshot, researchers could watch what happened to people’s sleep when they changed their habits – started exercising, kept it up, or quit.
To focus on people who had room to improve, the researchers excluded anyone already diagnosed with a sleep disorder and anyone who already reported sleeping restfully at the start.
The outcome was “perceived sleep restfulness” – basically, whether people felt they got enough rest from their sleep. It’s self-reported, not measured by a sleep lab or wearable.
You can read the study abstract, titled “Initiation, Maintenance, and Discontinuation of Habitual Exercise and Perceived Sleep Restfulness,” on the journal’s site.
Exercise for Better Sleep: The Key Numbers
Here’s how the three exercise patterns stacked up, as adjusted odds of improved sleep restfulness:
| Exercise pattern | Adjusted odds ratio (95% CI) | What it means |
|---|---|---|
| Started regular exercise | 1.37 (1.34-1.40) | About 37% higher odds of feeling more rested |
| Kept up regular exercise | 1.23 (1.21-1.25) | About 23% higher odds, even among people already exercising |
| Stopped regular exercise | 0.94 (0.92-0.97) | About 6% lower odds – quitting lost ground |
The “kept it up” finding is quietly encouraging. It applied to people who were already exercising but still didn’t feel rested. Sticking with the habit was still tied to improvement a year later.
The authors concluded that starting regular exercise may contribute to better sleep restfulness, and that maintaining the habit may help even people who already exercise.
One quick math note: a 37% increase in odds isn’t the same as a 37% increase in your personal chance of sleeping better. It’s a relative comparison between groups. Still, in a sample this large, the pattern is hard to ignore.
Why Structured Exercise Beat Daily Steps
This is the twist that got the study noticed. The researchers compared two different things:
- Regular exercise – planned, sweat-breaking workouts.
- Daily physical activity – general movement like walking around during your day.
For context, Japan’s standard health checkup questionnaire asks two separate questions along these lines: whether you exercise enough to sweat lightly for 30+ minutes at a time, twice a week, for over a year – and whether you walk or do equivalent activity for more than an hour a day.
Regular exercise showed a steady, logical pattern: start and you gain, keep going and you gain, stop and you lose. Daily physical activity didn’t. Starting more daily activity was linked to better restfulness (odds ratio 1.24), but maintaining it showed no effect (1.00), and stopping it was oddly linked to slightly better restfulness (1.07).
That inconsistency is why the researchers pointed to regular exercise – not step counts – as the habit most clearly tied to feeling rested. As wellness site mindbodygreen summarized it, structured movement seems to matter more for sleep than incidental movement like walking to the kitchen.
Important: this doesn’t mean walking is useless. Movement is great for your heart, mood and metabolism. It just suggests that if you want exercise for better sleep, a planned workout may be the better bet than simply racking up steps. If you’re short on time, our guide to movement snacks shows how to fit short bursts into a busy day.
Association, Not Causation: What the Study Can’t Prove
This is an observational study. It shows a strong link between exercise habits and feeling rested, but it can’t prove that exercise caused the better sleep.
A few limits worth keeping in mind:
- Self-reported data. Both exercise and sleep restfulness came from questionnaires, not trackers or sleep studies.
- Reverse causation. People who start sleeping better may have more energy to start exercising – the arrow could point both ways.
- Other life changes. A new job, less stress or better health could drive both better sleep and more exercise.
- One country, one year. The data come from Japanese adults over a single year, during 2021-2022. Results may differ elsewhere.
Psychology Today contributor Blake Griffin Edwards, a licensed marriage and family therapist, made the same point when writing about the study: these are strong associations, not ironclad proof, and people who feel better may simply be more inclined to exercise.
The good news for anyone trying exercise for better sleep: the finding lines up with decades of other research, including randomized trials. The CDC notes that regular physical activity can improve sleep quality, alongside lowering anxiety and blood pressure.
How Much Exercise for Better Sleep?
The Japanese study didn’t test a specific dose. But US guidelines give a solid target. According to the CDC’s adult activity guidelines, adults need:
- At least 150 minutes a week of moderate-intensity activity (like brisk walking), such as 30 minutes a day, 5 days a week – or 75 minutes of vigorous activity.
- 2 days a week of muscle-strengthening activity that works all major muscle groups.
The Japanese checkup definition of “regular exercise” – roughly two 30-minute sweaty sessions a week – is a lot less than that. That’s a friendly starting line if you’re currently doing nothing.
Does evening exercise ruin your sleep?
Probably not, for most people. A 2019 review in Sports Medicine by Jan Stutz and colleagues pooled 23 studies and found that evening exercise did not generally hurt sleep in healthy adults.
The exception: vigorous exercise that ends within about an hour of bedtime may delay falling asleep and cut sleep efficiency. If you train at night, keep the hard stuff earlier and wind down with something gentler.
Your 4-Week Exercise for Better Sleep Plan
Want to test the idea on yourself? Here’s a simple, low-stakes plan:
- Week 1: Schedule two sessions. Put two 30-minute workouts on your calendar – a brisk walk with hills, a bike ride, a class or a strength routine. Aim to sweat lightly.
- Week 2: Add a third. Three sessions a week, and make one of them strength training.
- Week 3: Lock in your timing. Finish vigorous workouts at least an hour before bed. Morning or afternoon sessions are easiest to protect.
- Week 4: Build toward 150. Stretch sessions or add short walks to approach 150 minutes of moderate activity a week.
Track just one thing each morning: on a 1-to-5 scale, how rested do you feel? It mirrors what the study measured, and after a month you’ll have your own data.
Be patient. Habits take time – often much longer than the “21 days” myth, as we explained in why it takes about 66 days to form a habit. And if you’ve fallen off the wagon, the study suggests restarting is exactly where the biggest link showed up.
The Bottom Line on Exercise for Better Sleep
A 702,007-person study suggests that starting and sticking with a regular workout habit is linked to feeling more rested – while quitting is linked to losing ground. Everyday steps alone showed no consistent pattern.
It’s not proof of cause and effect, and it measured how rested people felt, not how long they slept. But it’s a cheap, low-risk experiment with plenty of other health upsides. Sleep is foundational – our breakdown of research linking REM sleep to lower disease risk shows just how much rides on it.
Your move: pick two 30-minute workout slots for this week and put them on the calendar today. If you have a health condition, haven’t exercised in a while, or struggle with ongoing insomnia, snoring or daytime sleepiness, talk to your doctor first – persistent sleep problems can have medical causes worth checking.
This article is for general information and isn’t medical advice. Talk to your doctor before starting a new exercise program.
