This post is part of a series on non-medication treatments of depressed mood. Previous posts reviewed the evidence for folate, B-12, SAMe, omega-3 fatty acids, the amino acids L-tryptophan and 5-HTP, and the prohormone dehydroepiandrosterone (DHEA). This post is offered as a concise review of the evidence for the benefits of regular exercise in depression. You can find out more about a wide range of alternative and integrative approaches for depressed mood and other mental health problems on my website.
How exercise improves depressed mood
The beneficial mood-elevating effects of exercise are probably related to short-term transient responses in the brain immediately following exercise, as well as long-term changes following two or more periods of exercise. Findings of animal and human studies suggest that both the immediate and long-term beneficial effects of exercise on mood are mediated by multiple factors that increase brain levels of mood-elevating endorphins, dopamine, norepinephrine, and serotonin, promote the development of new neurons in the brain (i.e. neurogenesis), reduce oxidative stress, and enhance immune functioning (Schuch 2016). Findings of a recent fMRI pilot study suggest that regular exercise may promote increased neuroplasticity in certain brain regions, resulting in improved mood (Gourgouvelis 2017).
In addition to the direct and indirect effects of exercise on brain function, regular exercise also enhances self-sufficiency and ensures positive social interactions with other people. It is difficult to separate beneficial effects of exercise from other lifestyle factors, and it is possible that exercise contributes to overall feelings of wellness while not having specific mood elevating effects. Finally, regular exercise has been shown to improve sleep quality in individuals who do not respond to antidepressants (Rethorst 2013). This may be a significant benefit of exercise on overall resilience and day to day functioning in view of the high prevalence rate of insomnia in chronically depressed individuals.
Review of research findings
The following section is a brief review of research findings on exercise as a stand-alone therapy for depressed mood, and as an ‘add-on’ therapy for individuals taking an antidepressant, engaging in cognitive behavioral therapy, or using bright light exposure therapy.
Mood enhancing benefits of regular exercise
Findings of controlled trials and systematic reviews report consistent mood-enhancing effects of regular exercise. Individuals who are less sedentary have a reduced risk of both depressed mood and cardiovascular disease (Schuch 2017). Both aerobic exercise and non-aerobic strengthening exercises are believed to be equally efficacious. The optimum duration and frequency of exercise needed to improve depressed mood have not yet been determined but probably vary with age and conditioning. Regular aerobic exercise may improve cognitive functioning in chronically depressed individuals who often experience difficulties with thinking and memory (Oertel-Knochel 2014).
Regular exercise as an ‘add-on’ therapy to antidepressants and other treatments
A recent meta-analysis of controlled studies (977 total subjects) on exercise used either as a single intervention or in combination with antidepressants reported that regular exercise has consistent beneficial effects on depressed mood (Kvam 2016). A systematic review of studies on exercise as an add-on therapy in individuals diagnosed with major depressive disorder found that depressed individuals who exercise regularly respond consistently better than individuals who take an antidepressant but do not exercise (Mura 2014).
Adding regular exercise to ongoing antidepressant and cognitive therapy improves treatment response (Gourgouvelis 2018). Moderately depressed individuals who exercise in addition to receiving regular cognitive behavioral therapy (CBT) are less depressed and report less frequent suicidal thoughts compared to individuals engaged in CBT only (Abdollahi 2017). Antidepressants and exercise probably have equivalent effects on moderate depressed mood (Blumenthal 2007). The therapeutic benefits of regular exercise may also be comparable to validated complementary and alternative (CAM) treatments of depressed mood such as St. John’s Wort (Hypericum perforatum) (Ernst 1998).
Depressed patients who exercise in a brightly lit (2500 to 4000 lux) indoor environment experience more significant improvements in mood and greater feelings of vitality compared to depressed individuals who exercise indoors in ordinary room light (400 to 600 lux) (Partonen 1998). Depressed women patients who combined exercise with bright light exposure while taking a daily vitamin regimen reported significant improvements in mood (Brown 2001).
Individuals who have chronic pain conditions, heart disease, or other medical problems that might limit the amount of exercise they can do should consult with their family doctor, cardiologist, or other qualified health care provider before starting a regular exercise program or increasing their current level of activity.
Regular exercise has established mood-enhancing benefits in depressed individuals that may be equivalent to cognitive therapy. Regular exercise improves overall life quality and improves cognitive functioning and sleep quality—problems that often accompany chronic depressed mood. Combining regular exercise with an antidepressant enhances antidepressant response. Regular exercise may also enhance response to bright light exposure therapy and select alternative therapies. As exercise has established beneficial effects on the heart and body everyone struggling with depression should be encouraged to engage in a regular exercise program (i.e., unless a medical problem limits their activity).