Exercise may help people overcome mild to moderate depression. Previous studies have shown that younger and middle aged people benefit. (Keep reading for more details on those.) Scientists have evidence that exercise is effective even for those who are older than 50. Now, we have some information on how much exercise you need. A systematic review and meta-analysis shows that boosting the step count on a daily basis might be good enough.
Taking Steps Against Depression:
Spanish researchers analyzed 33 studies with 96,173 participants (JAMA Network Open, Dec. 16, 2024). These studies used step count as an objective measure of physical activity, rather than counting on people to estimate their own exercise levels. The analysis revealed that higher daily step counts were linked to fewer depressive symptoms.
People who logged at least 5,000 steps a day were less likely to suffer such symptoms than those who walked less. Many of these studies were cross-sectional, though, and did not track people over time. In prospective studies that did follow individuals for many months, people who took 7,000 or more steps daily were better able to ward off depression. Counts above 7500 steps a day were associated with a 42 percent lower likelihood of depression. The investigators point out that they don’t know if the optimal daily step count might differ by age, sex or other characteristic.
They concluded:
“The objective measurement of daily steps may represent an inclusive and comprehensive approach to public health that has the potential to prevent depression.”
Learning That Exercise Is Effective Against Depression in Seniors:
More than 4,000 participants in the Irish Longitudinal Study on Ageing answered questions about physical activity and mood every two years between October 2009 and December 2018. Those who exercised at least 20 minutes a day, at least five days a week, reduced their chance of experiencing depression by approximately 16 percent compared to those who were not active at all (JAMA Network Open, July 10, 2023). People who exercised more frequently, for a longer time period or more vigorously got more benefit, reducing their chance of depression by as much as 42 percent.
Previous research has shown that regular exercise works at least as well as medication against depression. This study confirms that exercise is effective, particularly for people with conditions like heart disease that can lead to depression. The researchers point out that 20 minutes five days a week is a lower “dose” than international public health organizations like WHO recommend for general health.
The investigators conclude,
“The findings of this cohort study suggest that physical activity doses lower (ie, 400 to <600 MET-min/wk) than doses recommended in guidelines for overall health (ie, 600 MET-min/wk) may protect against depressive symptoms and major depression among older adults.”
Previous Research Showing That Exercise Eases Depression:
Several meta-analyses have consolidated evidence from a number of randomized controlled trials. All of them found that physical exercise is effective in treating depression.
One study analyzed data from 35 trials that randomly assigned people to either exercise or control groups (The Cochrane Library, online, Sept 11, 2013). In these trials, exercise was roughly equivalent to antidepressant medication or psychotherapy in reducing depression symptoms. For example, in one study more than half of the older depressed patients who were randomized to an exercise program improved their mood, whereas only a third of the patients who went to informational talks experienced improvement. The collective research suggests that the more intense and regular the exercise, the greater the benefit.
Exercise Works Better Than Nothing:
A few years later, another meta-analysis included 23 randomized controlled trials (Journal of Affective Disorders, Sep. 15, 2016). Compared to no intervention, exercise had a significant positive effect. In comparison, trials comparing exercise to usual care found only a moderate effect size. The benefits of exercise over antidepressant medication in this analysis was small and not significant.
Nonetheless, the authors concluded:
“Physical exercise is an effective intervention for depression. It also could be a viable adjunct treatment in combination with antidepressants.”
Exercise Is Effective in Re-wiring the Brain:
A relatively recent review presented evidence that aerobic exercise, resistance exercise and mind-body exercise can all improve depressive symptoms (CNS Neuroscience & Therapeutics, Sep. 2020). The investigators suggested that physical activity can change the structure of the brain. We don’t know if this explains why exercise works as well as it does.
