Depression is a major health burden associated with poor quality of life and impaired functioning. Depression is a leading cause of disability worldwide and is associated with profound economic costs. Depression is usually treated with antidepressant medications and psychological therapy or combination of both. However, there are lot of limitations associated with these therapies and as a result, a number of alternative or adjunctive therapies have been sought for. Exercise is one such option with a lot of substantial supportive research. The objective of the article was to review the beneficial effects of exercise in depression. An electronic search of literature from inception till 06/2017 highlighting the effects of exercise on depression and the possible mechanistic pathways involved was conducted using PubMed/ Medline, Google scholar and Scopus and relevant articles were utilized for this review. The results of this review confirmed the beneficial role of exercise in depression as evidenced by the improvement in the outcomes and the various psychobiological parameters measured. Thus exercise can be considered as a treatment option for the management of depression.

Introduction

Major depressive disorder (MDD) is the commonly occurring psychiatric disorder with a life-time prevalence of 15–۲۰% and associated with significant morbidity, mortality and disability.1 Depression is characterized by fatigue, lack of energy, loss of interest in normal activities, sleep disturbances including insomnia or excessive sleeping, feelings of sadness, tearfulness, worthlessness or guilt etc. The patients with depression often have difficulty in thinking, concentration, making decisions and remembering things.2 According to WHO (World Health Organization), depression is the leading cause of disability worldwide and is a major contributor to the overall global burden of disease. More women are affected by depression than men.3 The overall prevalence of depression in Europe is 8.5%.4 In the last decade, the global prevalence of depression is on the verge of increasing.5 In developing countries, 10 to 44% suffer from depression and anxiety disorders but the medical care is received by less than 35% of the depressed.6 The prevalence of depression in primary care varies between 15.3 and 22%, with global prevalence up to 13% and between 17 and 46% in Saudi Arabia.7 The patients with depression are usually treated with medication or psychotherapy or a combination of both.8 Many of the depressed people do not seek any treatment and hence depression generally remains to be one of the most undertreated conditions.9,10 Approximately only 12% of the people with depression seek professional help, partly because of the stigma associated with it.10 Only 18% to 25% of the treated depressed patients in the United States have been reported to receive adequate treatment.11 The most commonly used treatments being second generation antidepressants.12 However, patients on antidepressant treatments often experience adverse events and are unable to continue with the treatment.13,14 Most of the patients on antidepressant medications do not achieve remission after initial treatment15 and nearly one-third of the patients do not achieve remission even after several treatment steps.16,17 The patients with depression usually have poor compliance to the medication regimens.9,18,19 The patients with depression have higher treatmentspecific stigma with antidepressant medication than for example with herbal remedies.20 Because of all these limitations, there is a lot of emphasis on alternative treatment options. Physical exercise (PE) is one such option which has gained considerable attention.