Exercise is widely recommended as a first-line treatment for depression of all types. Many people have personal experience of feeling better and healthier when they integrate an exercise routine into their lives, and there are many studies showing measurable effects of exercise on clinical depression. However, most of these studies are small, and there are few solid conclusions that can be drawn about whether some types of exercise are better than others, and the importance of specific duration and intensity of exercise for depression.
A recent systemic review published in BMJ attempted to extract concrete conclusions from the wide variety of studies available. The systemic review process collects published studies and looks for ways to make their results comparable in order to find reliable data that can be useful in clinical settings. This review, published in February, 2024, looked at 218 unique studies with a total of 14,170 participants and concluded that: “Exercise is an effective treatment for depression, with walking or jogging, yoga, and strength training more effective than other exercises, particularly when intense. Yoga and strength training were well tolerated compared with other treatments.”
Overall, the survey found that exercise has “moderate” effects on depression, but the evidence is not so strong, and the study authors suggest that treatment guidelines may err on the side of being “overly conservative” by only offering exercise on a “conditional” basis. They believe that the evidence weighs strongly enough that guidelines for treatment of depression should always include exercise, with attention paid to individual characteristics, and greater intensity of exercise recommended to everyone.
How does exercise reduce depression?
The research did not come to clear conclusions about how exercise works to alleviate depression, and the authors emphasize that more research is needed. Trends in the data suggest a few factors such as: “social interaction, mindfulness or experiential acceptance, increased self-efficacy, immersion in green spaces, neurobiological mechanisms, and acute positive affect” combine to produce the effects seen. How each of these works as part of the whole, and whether one or more have greater effects in different populations remains to be studied.
What kind of exercise with help me?
Other suggestive trends in the data suggest that strength training was helpful for women in their 30’s, while yoga classes were helpful for older men (>60). These were “well-tolerated” meaning that participants stuck with the activities and dropped out less often. They also found that a more prescriptive set of instructions about what to do and how much were often more effective than more “autonomy” in which the doctor just said “do some kind of exercise”. Possibly participants found it easier, especially in the beginning to simply follow instructions.
The authors conclude: “exercise may therefore be considered a viable alternative to drug treatment. We also found evidence that exercise increases the effects of SSRIs, so offering exercise may act as an adjuvant for those already taking drugs. We agree with consensus statements that professionals should still account for patients’ values, preferences, and constraints, ensuring there is shared decision making around what best suits the patient. Our review provides data to help inform that decision.”
Reference:
Noetel, M. et al. Effect of exercise for depression: systematic review and network meta-analysis of randomized controlled trials. BMJ 2024; 384 doi: https://doi.org/10.1136/bmj-2023-075847 (Published 14 February 2024). BMJ 2024;384:e075847
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