People with non-communicable chronic health conditions such as cardiovascular disease, cancer, respiratory disease and type 2 diabetes have higher rates of symptoms of depression than the general population. Symptoms of depression are also an adverse prognostic factor for these conditions. Aerobic exercise is accepted as an effective treatment option for depression in people without comorbid chronic disease. This systematic review aimed to estimate the effects of aerobic exercise compared to usual care on symptoms of depression in people with chronic diseases.
Sensitive searches of three databases identified (non-)randomised controlled trials that recruited adults with cardiovascular disease, cancer, respiratory disease or type 2 diabetes. Trials had to compare an aerobic exercise intervention (delivered at least twice per week, achieving at least moderate intensity exercise, for a minimum of 4 weeks) to usual care. Trials where usual care involved any type of exercise were excluded. The outcome was depression assessed by clinical assessment or symptoms of depression measured using a validated questionnaire. Two independent reviewers selected trials and extracted the data. Trial quality was evaluated with the Downs and Black checklist and certainty of the evidence with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool. Meta-analyses were reported as standardised mean difference (SMD) and 95% confidence interval (CI). Five subgroup analyses were prespecified and estimated via meta-regression: (1) type of condition; (2) frequency of exercise < =3 vs. >3 sessions/week; (3) duration of sessions < =30 vs. >30 minutes; (4) length of program <12 vs. >=12 weeks.
30 randomised controlled trials and 2 non-randomised trials (4,111 participants) were included in the review, 24 of which reported data suitable for meta-analysis. Interventions were delivered 2 to 5 sessions/week for 20 to 80 minutes/session for 4 to 24 weeks. Eleven studies included people with cardiovascular disease, 10 with cancer, 2 with respiratory disease and 1 with diabetes.
There was low certainty evidence that exercise improved symptoms of depression in people with chronic conditions (SMD 0.5, 95% CI 0.25 to 0.76, 24 trials) compared to usual care. There was moderate certainty evidence that aerobic exercise improved symptoms of depression in cardiovascular disease (SMD 0.67, 95% CI 0.35 to 0.99, 11 trials), and low certainty in cancer (SMD 0.22, 95% CI 0.07 to 0.37, 10 trials). There was low certainty of no effect in respiratory disease (SMD 0.98, 95% CI -0.01 to 1.96, 2 trials) and diabetes (SMD 0.11, 95% CI -0.43 to 0.65, 1 trial). Meta-regression did not show that session frequency, session duration or program length influenced effect size.
Aerobic exercise has potentially clinically important effects on symptoms of depression in people with chronic non-communicable diseases. Certainty of evidence is strongest in people with cardiovascular disease. The exercise programs investigated targeted the health effects of the chronic conditions and were not specifically designed for symptoms of depression per se. It is also worth noting that this systematic review did not aim to assess the effect of exercise in people with clinical diagnosis of major depressive disorder.
Beland M, et al. Aerobic exercise alleviates depressive symptoms in patients with a major non-communicable chronic disease: a systematic review and meta-analysis. Brit J Sports Med 2020;54:272-8