Globally, more than 264 million people of all ages suffer from depression (James et al., 2018), a mental illness that differs from the usual mood swings and emotional reactions of everyday life. When an individual suffers from long-term and moderate or severe symptoms, depression is considered a serious health disorder (WHO, 2021). A significant proportion of individuals affected by depression, up to 30%, are considered resistant to treatment (Warden et al., 2007). Therefore, new strategies or new additions to the treatment of depressive disorders are necessary and under research1.
As evidence from several studies and meta-analyses have indicated, exercise has positive effects on symptom severity and cognitive symptoms of depression, (Krogh et al., 2011; Kvam et al., 2016; Morres et al., 2019b). The antidepressant effect of exercise is mediated through multiple biological and psychosocial pathways5.
As part of a study examining the effect of exercise on symptoms in adult patients with depression, data were collected from 455 patients with a clinical diagnosis of major depression, through mental health services. The exercise was applied on average for:
- 45 minutes,
- at moderate intensity,
- 3 times/week,
- for about 9 weeks
and showed a significantly large overall antidepressant effect. Regardless of the severity of depressive symptoms, aerobic physical activity emerged as an effective intervention for depression.
In addition, exercise is a promising provision for the physical and mental health of adolescents. Adolescents treated for depression have been shown to experience a mostly sedentary lifestyle. In a study of adolescent patients3 hospitalized for depression and anxiety, adjunctive exercise therapy seemed to reduce depressive symptoms. A program of structured physical exercise 3-4 times/week, over a 6-week period, was implemented and the results supported the fact that exercise is beneficial, if incorporated as an adjunctive treatment in psychiatric settings for adolescents with depression.
How can exercise act biochemically?
Brain-derived neurotrophic factor (BDNF) is a protein that acts on certain neurons in the central nervous system and peripheral nervous system by helping existing neurons survive and encouraging the growth and differentiation of new neurons and synapses. Vigorous exercise, particularly high-intensity exercise, increases BDNF levels in healthy humans as well as in clinical populations, as demonstrated by aerobic and resistance exercise studies4. A temporary increase in BDNF concentration has been observed, which quickly returns to baseline levels, possibly indicating rapid reuptake by the brain, aiding its neuroplasticity functions. Overall, the evidence suggests that antidepressants also increase (or lead to an increase in) peripheral BDNF levels in patients suffering from depression, with some evidence indicating to be accompanied by some reduction in depression severity.
Exercise also works by releasing endorphins and other natural cannabis-like brain chemicals (endogenous cannabinoids) that can enhance feelings of well-being.
On a final note, strong research evidence encourages exercise in all types of depression4, after clinical assessment of patients’ ability and willingness to exercise. Patients with mild to moderate depression could benefit from exercise and be led to a smaller or larger reduction in medication dosage or to avoid combinations of antidepressants that are sometimes used in severe or treatment-resistant types of depression.
Exercise, though, is not the only and universal solution to the worldwide growing problem of depression, and this type of treatment is not a panacea for all depressed patients.
In the same way that medication and psychotherapy do not have the same effectiveness for everyone, exercise must also be adapted to each patient’s needs.
This requires close collaboration between the patient’s medical team and physical education and sports science experts in order to successfully determine the method of optimal exercise, intensity and duration to be prescribed to the individual with depression. With appropriate planning, exercise can be recommended to individuals with mild to moderate depression who are willing, motivated, and physically healthy enough to participate in a structured exercise program.
- Morres, ID, Hatzigeorgiadis, A, Stathi, A, et al. Aerobic exercise for adult patients with major depressive disorder in mental health services: A systematic review and meta-analysis. Depress Anxiety. 2019; 36: 39– 53. https://doi.org/10.1002/da.22842
- Josefsson, T., Lindwall, M. and Archer, T. (2014), Exercise intervention in depressive disorders. Scand J Med Sci Sports, 24: 259-272. https://doi.org/10.1111/sms.12050
- Philippot A, Dubois V, Lambrechts K, Grogna D, Robert A, Jonckheer U, Chakib W, Beine A, Bleyenheuft Y, De Volder AG. Impact of physical exercise on depression and anxiety in adolescent inpatients: A randomized controlled trial. J Affect Disord. 2022 Mar 15;301:145-153. doi: 10.1016/j.jad.2022.01.011. Epub 2022 Jan 7. PMID: 35007642.
- Jemni M, Zaman R, Carrick FR, Clarke ND, Marina M, Bottoms L, Matharoo JS, Ramsbottom R, Hoffman N, Groves SJ, Gu Y, Konukman F. Exercise improves depression through positive modulation of brain-derived neurotrophic factor (BDNF). A review based on 100 manuscripts over 20 years. Front Physiol. 2023 Mar 8;14:1102526. doi: 10.3389/fphys.2023.1102526. PMID: 36969600; PMCID: PMC10030936.
- Kandola A, Ashdown-Franks G, Hendrikse J, Sabiston CM, Stubbs B. Physical activity and depression: Towards understanding the antidepressant mechanisms of physical activity. Neurosci Biobehav Rev. 2019 Dec;107:525-539. doi: 10.1016/j.neubiorev.2019.09.040. Epub 2019 Oct 2. PMID: 31586447.
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