Does Exercise Really Improve Your Mood? What the Evidence Shows

In 2023 a team of Australian researchers led by Ben Singh set out to answer a question that had already been studied hundreds of times: does physical activity help with depression, anxiety and psychological distress? Instead of running another trial, they collected the systematic reviews that had already combined the trials.

They found 97 of them. Together those reviews covered 1,039 randomised trials and 128,119 participants: healthy adults, people with diagnosed mental health conditions, and people living with a range of chronic illnesses.

The headline result was clear. Compared with usual care, physical activity had a medium-sized effect on symptoms of depression and anxiety, and a somewhat larger one on general psychological distress. The authors concluded that physical activity should be a mainstay approach for these symptoms.

That is a strong conclusion, and it is broadly supported. It also comes with details that matter a lot for how you read it.

What a medium effect means

The review reported its results as standardised effect sizes: roughly 0.43 for depression, 0.42 for anxiety and 0.60 for distress. These numbers express how far, on average, the people who were active moved compared with the people who were not, measured in units of how much people naturally vary.

By the conventions psychologists use, 0.2 is small, 0.5 is medium and 0.8 is large. So these are genuine, noticeable improvements on average - not miracles, and not guaranteed for any one person. Some people improved a lot; others hardly at all.

The review also found a few patterns worth knowing. The benefits were largest in people with depression, people living with HIV or kidney disease, pregnant and postpartum women, and healthy individuals. Higher-intensity activity was associated with bigger improvements. And, less intuitively, longer programmes were not more effective: the effect tended to shrink as interventions went on for longer.

There was an important caveat in the fine print. Most of the reviews included - 77 out of 97 - scored critically low on a standard tool for judging the quality of systematic reviews. That does not mean the conclusion is wrong, but it does mean the evidence underneath it is less tidy than the headline suggests.

Can activity help prevent low mood?

Treating symptoms is one question. Preventing them is another. In 2018, Felipe Schuch and colleagues looked at 49 prospective studies that followed 266,939 people over time, adding up to more than 1.8 million person-years of observation.

People with high levels of physical activity had lower odds of later developing depression than people with low levels. After adjusting for other factors, the odds were about 17 per cent lower. The pattern held in young people, in adults and in older adults, and across regions including Asia, Europe, North America and Oceania. The researchers found signs of publication bias, but correcting for it did not change the size of the association.

Here the usual warning applies with full force. These were observational studies, not experiments. People who are more active may differ in many other ways - income, health, social life - and people who are beginning to feel low may already be moving less. The studies adjusted for some of this, but they cannot prove that the activity itself did the protecting.

Which kind of exercise?

A 2024 analysis in the BMJ, led by Michael Noetel, focused on people who met clinical criteria for major depression. It combined 218 studies with 14,170 participants and compared different types of exercise with each other and with other treatments.

Compared with active control conditions, walking or jogging showed the largest reductions in depression, followed by yoga, strength training, mixed aerobic exercise, and tai chi or qigong. All were in the moderate range. The effects rose with the intensity prescribed, and yoga and strength training appeared to be the easiest for people to stick with.

The authors were candid about the limits. Only one of the 218 studies met strict criteria for low risk of bias, and their confidence in the results was rated low for walking or jogging and very low for the others. One reason is almost unavoidable: you cannot hide from people that they are exercising, so their expectations may account for part of the improvement.

Keeping the evidence in proportion

Put together, these studies tell a consistent story. Moving more is linked to fewer symptoms of depression and anxiety, randomised trials suggest the link is at least partly causal, and the size of the benefit is meaningful. That is about as good as evidence in this area gets.

What the evidence does not say is just as important. It does not say that exercise replaces professional treatment, that it works for everybody, or that a person who is struggling simply needs to try harder at the gym. The BMJ authors suggested that exercise could be considered alongside psychotherapy and medication, not instead of them. This article is not medical advice.

What this means for you

If you are curious about what gets you moving - or what keeps you on the sofa - our exercise motivation test explores the reasons people are active. Our stress level test and our happiness test give a snapshot of how you are feeling lately. None of them measures depression or anxiety, and none can tell you whether exercise will help you in particular.

A few takeaways follow from the research itself:

• Many forms count. Walking, jogging, yoga, strength training and gentle practices like tai chi all showed benefits in trials. You do not need a specific programme.
• Intensity seems to matter. Across both big reviews, more vigorous activity was associated with larger improvements - within what is safe and sensible for your body.
• Sticking with it matters too. An activity you keep doing is worth more than a better one you abandon, which may be part of why well-tolerated options such as yoga and strength training stood out.
• Expect a modest, real effect. A medium effect is worth having. It is not a switch that turns low mood off.

If you are dealing with persistent low mood, anxiety or distress, or you have a health condition that affects what exercise is safe for you, talk to a doctor or another qualified professional before relying on exercise alone.