Does exercise improve mood? What the research shows, and how to test it on yourself

Two kinds of research answer this question, and it helps to keep them apart. The first is very large observational studies: they ask thousands, sometimes millions, of people how much they move and how they feel. They can show a strong link, but they cannot say which one drives the other. People who feel better may simply move more.

The second is randomized controlled trials, where participants are assigned by chance to exercise or not. They are stronger evidence for cause and effect, but they are usually smaller and shorter. Below we look at one large source of each kind.

Published in The Lancet Psychiatry in 2018, the study analyzed data from 1,237,194 adults in the CDC's Behavioral Risk Factor Surveillance System surveys from 2011, 2013 and 2015. The researchers matched people who exercised with people who did not but were similar in age, gender, income, education, body mass index, physical health and whether they had ever been diagnosed with depression.

• People who exercised reported 1.49 fewer days (43.2%) of poor mental health in the past month.
• Every type of exercise studied was linked to a lower burden, from 11.8% to 22.3% depending on the type.
• The largest differences were for team sports (22.3%), cycling (21.6%) and aerobic and gym activities (20.1%).
• The strongest links showed up for sessions of about 45 minutes, three to five times a week. In the authors' words, more exercise was not always better.

The limit, stated plainly: this was a cross-sectional study based on what people reported about themselves. It does not prove that exercise improved anyone's mood, and the authors themselves say the specific types and amounts should be tested in interventional studies.

An umbrella review published in the British Journal of Sports Medicine in 2023 pooled meta-analyses of randomized trials that aimed to increase physical activity in adults: 97 reviews, 1,039 trials and 128,119 participants. Compared with usual care, physical activity led to medium reductions in symptoms of depression, anxiety and psychological distress.

• The largest benefits were seen in people with depression, people with HIV or kidney disease, pregnant and postpartum women, and healthy adults.
• Higher intensity activity was linked to greater improvements in symptoms.
• The longer a program ran, the smaller its effect.

There is a caveat here too: 77 of the 97 reviews scored “critically low” on a quality rating. And a medium effect means a noticeable improvement on average. It does not mean everyone improves, or that exercise alone is enough.

The World Health Organization recommends at least 150 minutes of moderate-intensity physical activity a week for adults and stresses that any amount is better than none. The NHS adds that if you have been inactive for a while, you should build up to that target gradually, and that even a short brisk walk can help.

When your mood is low, getting moving can be one of the hardest things to do. So shrink the threshold, not the goal. The NHS keeps its advice simple: choose something you enjoy, because enjoyment makes it easier to stick with; make it regular; and start slowly if you have been inactive.

1. 1Start with the easiest version: you do not have to run, a ten minute walk counts.
2. 2Attach it to something you already do, such as the ten minutes after lunch or the trip home from work.
3. 3Set a floor, not a target: “I'll go out for five minutes and can turn back if I want.” On most days that is enough to get going.
4. 4If you have a health condition or have not exercised in a long time, check with a doctor before you start.

Research describes the average, and you are not the average. The simplest way to see what movement does for you is a small personal experiment over a few weeks:

1. 1For four weeks, log your mood every day at the same time on one simple scale.
2. 2Tag the days you moved: “walk”, “gym”, “run”. Always use the same word.
3. 3Compare after three or four weeks: do tagged days look different from untagged ones?
4. 4Note the other factors too. Weekends, a bad night's sleep or a heavy workday can explain part of the difference.

Small differences can be noise, and one bad day after a run proves nothing. Sleep is one of the biggest influences on mood, which we cover in how sleep affects mood. For the basics of logging, read how to keep a mood journal.

According to the NHS, exercise is especially useful for people with less severe depression. NICE, the clinical guidance body in England, recommends group exercise as one option for less severe depression, usually more than one session a week with a trained practitioner over about ten weeks.

But exercise does not replace treatment. If you have felt down for a while and do not feel like yourself, the NHS advises seeing a doctor; options include talking therapies, antidepressants and self-help. If you take medication, do not stop it because you started exercising; talk any change through with your doctor.

Pixmood is a mood journal, not a fitness app. You mark your day in five seconds by tapping one of five moods and, if you like, add a one word tag of up to 20 characters: “walk”, “gym”, “swim”. The tag stays with the day, so weeks later you can look at how your active days color the week and month mosaic.

In Pixmood Pro, the “Tags and your mood” card shows which tags you have used at least three times tend to come with your better days and which with your harder ones. With Pro you can also track energy and see how it relates to your mood. Insights start after at least seven entries, and everything is calculated on your phone.

The limits: Pixmood does not count steps, log workouts or connect to Apple Health or any other health app. A link between a tag and your mood is a pattern in your own entries, not proof that exercise changed it.

If you have felt down for a while and do not feel like yourself, or your sleep, appetite, work or relationships are affected, see a doctor; exercise does not replace that step. If you are thinking about harming yourself or you are in danger, call your local emergency number now (911 in the US and Canada, 999 in the UK, 000 in Australia, 112 in the EU). In the US and Canada you can also call or text 988, any time. In the UK and Ireland, Samaritans answer free on 116 123, day or night. In Australia, call Lifeline on 13 11 14.