Exercise does help with depression and anxiety, and you don’t need a lot of it.
The old wisdom about exercising to beat the blues has been confirmed in a large systematic review of systematic reviews, including what The Back Pages hopes is called a metametaanalysis.
Taken together with the mental health benefits of cold-water swimming we explored a fortnight ago, it feels as though a British sergeant-major is about to march into the story proclaiming there’s nothing wrong with you that a five-mile run and a cold bath won’t fix.
The new study, published in the British Journal of Sports Medicine, reviewed 97 reviews comprising 1039 randomised controlled trials with a total 130,000 participants, which all tested the effects of a physical activity (PA) intervention on anxiety, depression and psychological distress.
The studies variously included samples from the general population, people with a mental health diagnosis and people with other clinical diagnoses.
The results are, overall, one giant unsurprising tick for PA as a reliever of depression, anxiety and distress.
The biggest benefits were seen in people with depression, pregnant and postpartum women, “apparently healthy individuals” and people with HIV and kidney disease. The larger effect sizes in clinical groups, the authors say, probably reflects their greater prevalence of depressive symptoms and lower PA levels at baseline.
All kinds of physical activity helped, including including aerobic, resistance, mixed-mode exercise and yoga. Resistance had the largest effects on depression, while “yoga and other mind-body exercises were most effective for reducing anxiety”.
Higher intensity was better for depression and anxiety, possibly because low-intensity exercise doesn’t achieve the necessary “increased expression of neurotrophic factors, increased availability of serotonin and norepinephrine, regulation of hypothalamic-pituitary-adrenal axis activity and reduced systemic inflammation”.
The relationship was not as dose-dependent as you might expect. Longer-duration activities still had positive effects but less than that of short and mid-duration activities, possibly reflecting lower adherence.
While the press release we received shouts “Exercise more effective than medicines to manage mental health”, the paper doesn’t actually compare physical activity with medications. To meet the initial inclusion criteria for review, a review had to review (I said this was meta) mostly RCTs comparing exercise to “usual care, waitlist, nothing, an equal attention intervention or a lower/lesser PA intervention”. The team adjusted these criteria to exclude reviews where more than 25% of component RCTs “compared PA to pharmaceutical interventions or compared two types of equal dose exercise … without a non-PA comparison, since the inclusion of such reviews would limit our ability to evaluate the effectiveness of PA per se”.
The authors conclude by making the case for wider prescription of physical activity for patients with psychiatric and other clinical diagnoses, not as an afterthought but as a “mainstay approach”: “While the benefit of exercise for depression and anxiety is generally recognised, it is often overlooked in the management of these conditions.”
Sending penny@medicalrepublic.com.au a story tip is metabolically equivalent to a 5km run and a half-hour weights session.
