There is a growing pool of research that looks into the impact that exercise can have on depression, but this systematic review and meta-analysis claims to be the first summary of trials into the effects of exercise training on depressive symptoms among patients with a chronic illness.

The research team from the University of Alabama conducted a thorough search and identified 90 trials involving 10,534 sedentary patients with a chronic illness. Their included trials that:

• Randomised patients to exercise or a non-exercise comparison group
• Assessed depression outcomes before during and after the intervention

The review reported that depression in chronic illness is reduced by exercise in patients who are most depressed and who stick to the regimen.

The reviewers concluded:

Exercise reduces depressive symptoms among patients with a chronic illness. Patients with depressive symptoms indicative of mild-to-moderate depression and for whom exercise training improves function-related outcomes achieve the largest antidepressant effects.

Herring MP, Puetz TW, O’Connor PJ, Dishman RK. Effect of Exercise Training on Depressive Symptoms Among Patients With a Chronic Illness: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Arch Intern Med. 2012 Jan 23;172(2):101-11. [PubMed abstract]