Exercise can reduce symptoms of depression and anxiety, confirms review of reviews

When someone experiences depression or anxiety, there are a number of possible treatments, including therapy, medication, and lifestyle changes. Patients are often encouraged to engage in sports, arts, and other activities – a process known as "social prescribing" – and exercise in particular is frequently cited as a way to manage or improve mental health. But just how effective is it in treating these conditions?

This is the question posed by a team writing in the British Journal of Sports Medicine, who in a "meta review" looked at evidence from existing reviews of studies into the effectiveness of exercise in treating symptoms of depression and anxiety. The review finds that exercise can reduce symptoms to a similar extent as medication or therapy – a finding which, the researchers argue, suggests that exercise should be a "mainstay" approach for treating these conditions.

The team analysed nearly one hundred reviews of studies that explored the effectiveness of exercise for reducing symptoms of anxiety and depression, both in those with mental health diagnoses and those with chronic illnesses.

Reviews were eligible if they included studies with adult participants, and compared groups who did and did not take part in some form of physical activity intervention. Such interventions included a range of exercises such as aerobics or yoga, could be delivered online or in person, and varied in intensity, frequency, and duration. All studies included either self-report or clinician-rated assessments of depression, anxiety, or distress.

The results showed that physical activity was indeed associated with a reduction in depressive symptoms, both in those with and without a clinical diagnosis of depression. Physical activity also reduced symptoms of anxiety and psychological distress.

The studies included data from people with a range of clinical conditions. The researchers found that physical activity was effective in reducing depressive symptoms across all conditions, but that the greatest benefits were seen in those with depression, pregnant and postpartum women, and those with HIV or kidney disease (though healthy people also saw a positive impact on their mental health). The team suggests that people with these conditions may generally experience above average symptoms of depression, and have currently low physical activity levels, so see greater improvement compared to other populations.

All forms of physical activity were beneficial, though different forms of exercise did different things. For example, resistance exercise had the largest effects on depression, while yoga and "mind-body" exercises produced the greatest reductions in anxiety. This suggests that different kinds of exercise could be beneficial when people are experiencing different symptoms – a finding that could potentially help medical professionals suggest more appropriate forms of exercise rather than generalised physical activity programmes.

Higher intensity physical activity was associated with greater improvement for depression and anxiety. However, exercise with longer durations seemed less effective, and exercising fewer times a week had greater effects than exercising frequently throughout the week. The team suggests this may be because it is easier for people to maintain shorter and less frequent activities. They also note that this is an encouraging result, as it shows that even those who struggle to exercise could benefit from a small amount of activity per week.

The results of the study could also have wider implications. If exercise is just as effective as therapy and medication, it could be a first stage intervention for those experiencing depression or anxiety. However, these changes must be delivered with feedback and guidance from patients themselves: the team note that some patient groups are against prescribing exercise, and some have also written about frustrations about being told to "just exercise" to improve their mental health. Making sure a variety of options are available to patients, and allowing them to take the lead on deciding what kind of treatment is best suited for them, is likely to be a better approach than simply replacing medication or therapy with a prescription for yoga.