From the Guidelines
Physical activity has a significant biological effect on reducing depression, with regular exercise showing a large clinical effect on depressive symptoms, as evidenced by a standardized mean difference of −0.82 in a Cochrane review 1. The biological effects of physical activity on depression are multifaceted, including the regulation of the hypothalamic-pituitary-adrenal axis, which can be dysregulated in depression, leading to elevated cortisol levels, and exercise can improve this regulation 1. Additionally, physical activity can enhance immune function, which is often compromised in individuals with depression, and social contact through group exercise can provide further benefits 1. A meta-analysis of 13 studies found that depressive symptoms after stroke were lower immediately after ≥4 weeks of exercise, with a standardized mean difference of −0.13, indicating a small but beneficial effect of exercise on depressive symptoms 1. Another study found that physical activity is associated with a lower risk of depressive symptoms, with cohort research and RCTs supporting the beneficial effect of endurance training and strength training on reducing the risk of depressive symptoms 1. The most recent and highest quality study, a 2018 guideline, suggests that the effect of physical activity on the risk of depressive symptoms is convincing, with moderate to vigorous intensity endurance training and strength training showing beneficial effects 1. Key points to consider when using physical activity to reduce depression include:
- Aim for at least 30 minutes of moderate-intensity exercise, 3-5 times per week
- Even shorter sessions of 10-15 minutes can be beneficial if done consistently
- The type of exercise matters less than finding an activity that can be maintained consistently
- Exercise is most effective when combined with other depression treatments, but can be powerful on its own for mild to moderate depression.
From the Research
Biological Effects of Physical Activity on Depression
- Physical activity has been shown to be effective in treating mild-to-moderate depression and reducing mortality and symptoms of major depression 2.
- Exercise, a subset of physical activity, influences a range of biological and psychosocial processes also implicated in the pathophysiology of depression, including neuroplasticity, inflammation, oxidative stress, the endocrine system, self-esteem, social support, and self-efficacy 3.
- Regular physical activity has been found to be associated with a significant moderate reduction of depression in different groups by gender and age, and a physically active lifestyle is associated with lower levels of depression 4.
Mechanisms of Physical Activity's Antidepressant Effects
- Physical activity has been found to elicit changes in neuroplasticity, inflammation, oxidative stress, the endocrine system, self-esteem, social support, and self-efficacy, which are all implicated in the pathophysiology of depression 3.
- Exercise has been found to have a positive effect on depressive symptoms, similar to psychotherapeutic interventions, and this effect can be seen in as little as 4-8 weeks 4.
- The antidepressant mechanisms of physical activity are not yet fully established, but it is thought that physical activity may exert its effects through a combination of biological and psychosocial mechanisms 3.
Clinical Applications of Physical Activity in Depression Treatment
- Physical activity has been found to be a viable treatment for depression, and may be used as an alternative or adjunct to traditional treatments such as psychotherapy and antidepressant medications 5.
- Supervised physical exercise programs have been found to be effective in reducing depressive symptoms in older adults, and may be a useful alternative to antidepressant drug treatment in primary care settings 6.
- Physical activity may be a useful tool in the prevention and treatment of depression, and may have a protective effect against the development of clinical levels of depression and depressive symptoms 4.