Exercise improves cardiorespiratory fitness in people with depression: A meta-analysis of randomized control trials

Objective: Cardiorespiratory fitness (CRF) is an independent predictor of cardiovascular disease and all-cause mortality. CRF improves in response to exercise interventions, yet the effectiveness of such interventions to improve CRF among people with depression is unclear. We conducted a systematic review and meta-analysis to evaluate whether CRF improves in people with depression in exercise randomized control trials (RCTs). Method: Three authors identified RCTs from a recent Cochrane review and conducted updated searches of major electronic databases. We included RCTs of exercise interventions in people with depression (including major depressive disorder (MDD) and above-threshold depressive symptoms) that reported CRF (defined as predicted maximal oxygen uptake (VO(2)max predicted) or peak oxygen uptake (VO(2)peak)) versus a control condition. A random effects meta-analysis was conducted. Results: Seven unique RCTs including 8 aerobic exercise interventions for depression were eligible, including 293 people allocated to exercise (mean age=40.3 years, range=27.2-64.7years and 35-100% female) and 205 allocated to control conditions. Across all studies exercise results in a significant increase in CRF (g=0.64, 95%Cl=0.32-0.96, p<0.001) equating to a mean increase of 3.05 ml/kg/min. Results remained significant when restricted to MDD only (N=5, g=0.41, 95%Cl=0.18-0.64, p<0.001) and in high quality studies (N=5, g=0.60, 95%Cl =0.19-1.00, p=0.004). Conclusions: People with depression can achieve clinically relevant improvements in CRF in response to exercise interventions. Targeting 'fitness' rather than 'fatness' may be another feasible intervention strategy in this population. (C) 2015 Elsevier B.V. All rights reserved.