Exercise is 1.5 times more effective in treating depression and anxiety than counselling or medication, according to a new study.
Hitting the gym or going for a run can help with mild to moderate depression, scientists said.
Resistance work-outs had the largest impact on depression, while yoga and other mind-body exercises were most effective in reducing anxiety, according to University of South Australia’s research into 97 reviews, 1,039 trials and 128,119 participants.
Exercise interventions lasting 12 weeks or less had the strongest effect on mental health symptoms, versus long-haul fitness programmes.
The scientists claim this demonstrates the speed at which the benefits of exercise take hold.
They were surprised to discover clocking fewer hours in the gym a week offered a greater mental health boost than spending a large proportion of your time working out.
Addressing healthcare policy-makers, the researchers added: “It is a useful message that interventions do not need to provide high doses of PA for improvements in depression.
"Larger benefits are achieved from shorter interventions, which has health service delivery cost implications–suggesting that benefits can be obtained following short-term interventions, and intensive long-term interventions are not necessarily required to achieve therapeutic benefit."
The team suggested the unexpected results could be due to dwindling adherence to fitness programmes, or participants expecting more from the mental health programme if they put more time in.
Predictably, harder gym sessions reaped the most rewards - the scientists even warned that low-intensity exercise may not quite hit the mark for stimulating neurological and normal changes linked with improvements in depression and anxiety symptoms.
The perks of exercise were felt most keenly among participants with mild or moderate depression, those who were pregnant and postpartum, healthy people, and those diagnosed with HIV or kidney disease.
However, they emphasised that the evidence focussed on mild to moderate depression and few studies addressed anxiety and psychological distress.
Dr Ben Singh, lead UniSA researcher, said: “Physical activity is known to help improve mental health. Yet despite the evidence, it has not been widely adopted as a first-choice treatment.
“Our review shows that physical activity interventions can significantly reduce symptoms of depression and anxiety in all clinical populations, with some groups showing even greater signs of improvement.
“Higher intensity exercise had greater improvements for depression and anxiety, while longer durations had smaller effects when compared to short and mid-duration bursts.
“We also found that all types of physical activity and exercise were beneficial, including aerobic exercise such as walking, resistance training, Pilates, and yoga.
“Importantly, the research shows that it doesn’t take much for exercise to make a positive change to your mental health.”
Yoga, aerobic exercise, resistance weights and mix-mode work outs all had a positive effect.
According to the World Health Organisation, one in every eight people worldwide live with a mental disorder - a total of 970 million.
It costs the world economy over £2 trillion each year, with a rise to around £4.8 trillion by 2030.
Professor Carol Maher, UniSA’s senior researcher, said the study published in the British Journal of Sports Medicine is the first to evaluate the effects of every type of physical activity on depression, anxiety, and psychological distress in all adult populations.
She said: “Examining these studies as a whole is an effective way to for clinicians to easily understand the body of evidence that supports physical activity in managing mental health disorders.
“We hope this review will underscore the need for physical activity, including structured exercise interventions, as a mainstay approach for managing depression and anxiety.”
Writing in the journal the team said: "Results showed that physical activity is effective for reducing mild-to-moderate symptoms of depression, anxiety and psychological distress (median effect size range=−0.42 to –0.60), compared with usual care across all populations.
"Our findings underscore the important role of physical activity in the management of mild-to-moderate symptoms of depression, anxiety and psychological distress."
