A new study published yesterday suggests that even modest amounts of exercise could prevent some cases of depression. The prospective study monitored over 22,000 healthy people, seeing how many of them went on to develop depression over 11 years.
At follow-up and accounting for factors such as smoking, alcohol consumption, BMI, other illness and social support, people who, at the start of the study, said they didn't do any exercise had a 44% increased risk of developing depression compared to people doing just 1-2 hours of exercise per week. This outcome was the same for males and females, and younger and older people. On top of this it didn't seem to matter whether it was intense exercise. People didn't need to break a sweat to get the protection. Just moving was enough to reduce the likelihood of developing depression.
Why is this so important? Rates of depression and treatment-resistant depression (that don't respond to medication) are on the rise. If there is a causal relationship between exercise and depression (and no other confounding factors) this research suggests that 1 in 8 cases of depression could be *prevented* with just one hour a week of exercise (or that severity could be reduced). This research also helps shift the thinking from treatment to *prevention*. While many of the causes of depression such as genetics and traumatic life events are out of our control, physical activity is a 'modifiable risk factor' i.e. we can do something about it. And if we can save some people the distress of depression that is something everyone should get behind.
Exercise and the Prevention of Depression: Results of the HUNT Cohort Study.American Journal of Psychiatry Online. DOI: 10.1176/appi.ajp.2017.16111223