Exercise is one of the most common recommendations given to people who are feeling mentally low. Research has consistently shown that physical activity can improve mood and reduce stress. More recent and large-scale analyses even suggest that exercise may be as effective as psychotherapy or antidepressant medication in reducing symptoms of depression.
Two major studies published earlier this year have reinforced this idea.
What the research found
The first study, published in January by researchers in Britain and Ireland, was a Cochrane-style review, meaning it analysed a large number of existing clinical trials. It combined findings from 69 randomised controlled studiesexamining how exercise affects depression. The second study, published in February in the British Journal of Sports Medicine, expanded the evidence even further. Researchers analysed more than 1,000 studies involving nearly 80,000 participants. Both analyses reached a similar conclusion: exercise can reduce symptoms of depression and anxiety to a degree comparable with established treatments.
Why scientists remain cautious
Despite the encouraging results, researchers stress that there are important limitations. Meta-analyses depend heavily on the quality of the studies included. In exercise research, one common issue is participant awareness. People know whether they are exercising or not, which makes it difficult to conduct “blind” studies similar to those used in pharmaceutical trials.
This awareness may influence how participants evaluate their own mood. For this reason, the Cochrane review concluded that many of the studies involved had a high risk of bias. The second analysis also did not directly compare exercise with medication or therapy. Instead, it compared results across separate studies, which makes precise comparisons more difficult.
As neuroscientist Jonathan Roiser of University College London noted, “this is not a completely fair comparison.”
The proven benefits of exercise
Even with these reservations, scientists broadly agree that exercise has a positive effect on mental health. Aerobic activities such as walking, running and cycling appear to provide the most consistent benefits. In cases of depression, guided or group exercise programmes often work better than exercising alone. The effects are not immediate. Improvements in mood usually develop gradually and tend to become clearer after several months of regular activity.
For anxiety, moderate and gentler forms of exercise may be particularly helpful.
Why exercise helps the brain
Researchers still do not fully understand why exercise has such powerful mental-health effects. The long-standing theory that mood improvements are caused by endorphins has only limited scientific support. More recent evidence points to endocannabinoids, chemical compounds produced by the body that activate the same receptors as cannabis.
Exercise also appears to:
- reduce inflammation
- increase brain plasticity
- boost dopamine signalling, which is linked to motivation and reward
The benefits are not purely biological. Exercise can also provide a sense of achievement, restore feelings of control and gradually strengthen self-confidence, all of which contribute to improved emotional wellbeing.
Source: The Economist
