Evidence summary (Updated 2022)
A large review of 49 prospective cohort studies (1,837,794 patient-year follow-up) evaluating the incidence of depression compared to levels of physical activity has demonstrated that those with high levels of physical activity had a lower chance of developing depression when compared to those with low levels of physical activity (adjusted odds ration 0.83; 95% CI 0.79,0.88). This effect was observed regardless of age and geographical location [1].
A cross-sectional study of 4402 US medical students demonstrated overall higher quality of life scores, and lower features of burnout, in those who followed the recommended Centres for Disease Control & Prevention (CDC) exercise guidelines for both aerobic (51.3% vs 60.8%; p<0.0001) and strength-training exercise (51.8% vs 58.6%; p<0.0001), compared to those who did not meet the activity guidelines, independent of age, sex, relationship status, children & year of study [2]. Another prospective cohort study showed that regular moderate exercise for >15 minutes/session, 3x/week is significantly associated with a lower risk of depressive symptoms in older adults [3]. A cross-sectional survey-based study of individuals with a history of stroke demonstrated that physical activity reduced the risk of post-stroke depression by between 36.1- 42.4%, however this did not consider all factors, including severity of the stroke, pre-depression status and if there was a previous history of treatment for depression [4].
More recently, there is increasing interest in the value of exercise as a prevention for mental health issues. Several systematic reviews and meta- analysis were identified as part of the evidence update, all with varying outcomes. A recent large systematic review of 8 meta-analyses reported that exercise has a ‘moderate effects on decreasing symptoms of depression in the general population across a wide age- range’. They also noted that findings suggested no difference in efficacy between low intensity and high intensity exercise [5]. Another systematic review of 20 randomised control trials also concluded that physical activity is effective when combined with universal multiple risk lifestyle interventions for example smoking cessation, healthy diet in producing a small but statistically significant reduction in depressive symptoms [6].
A smaller recent systematic review that included studies with varying modes of exercise intervention such as walking, other aerobic exercise and Iyengar yoga, found that exercise interventions only had a small-effect on the reduction of depressive symptoms in people without clinical depression. The quality however of this evidence was deemed to be low due to the heterogeneity of interventions [7].
Quality of Evidence
Grade A – strong as large number of metanalyses with high numbers
Strength of recommendation
Grade 1 – strong as all show some benefit even if small
Conclusion
Physical activity may be effective at preventing depression, particularly when combined with multiple risk lifestyle interventions.
References
[1] Physical Activityand Incident Depression: A Meta-Analysis of Prospective Cohort Studies. Am J Psychiatry. 2018 Apr 25
[2] Healthy Exercise Habits Are Associated With Lower Risk of Burnout and Higher Quality of Life Among U.S. Medical Students. Acad Med. 2017 Jul;92(7):1006-1011.
[3] Effects of different amounts of exercise on preventing depressive symptoms in community-dwelling older adults: a prospective cohort study in Taiwan. BMJ Open. 2017 May 2;7(4): e014256
[4] Physical Activity and the Risk of Depression in Community-Dwelling Korean Adults With a History of Stroke. Phys Ther. 2017 Jan 1;97(1):105-113
[5] Hu MX, Turner D, Generaal E et al. (2020) Exercise interventions for the prevention of depression: a systematic review of meta-analyses. BMC public health, 20(1), pp.1-11.
[6] Gómez-Gómez I, Bellón JÁ, Resurrección DM et al. (2020) Effectiveness of universal multiple-risk lifestyle interventions in reducing depressive symptoms: systematic review and meta-analysis. Preventive Medicine, 134, p.106067.
[7] Bellón JÁ, Conejo-Cerón S, Sánchez-Calderón A et al. (2021) Effectiveness of exercise-based interventions in reducing depressive symptoms in people without clinical depression: systematic review and meta-analysis of randomised controlled trials. The British Journal of Psychiatry, pp.1-10.
[8] Caldwell DM, Davies SR, Thorn JC et al. (2021) School-based interventions to prevent anxiety, depression and conduct disorder in children and young people: a systematic review and network meta-analysis. Public Health Res;9(8).