Moderate to Intense Exercise Associated with Improved Depressive Symptoms in Subjects with Major Depressive Disorder

by | Apr 11, 2024 | 2024, Brain Health, Depression, Fitness and Exercise, Recent Articles

Written by Taylor Woosley, Science Writer. Results of the meta-analysis of 218 RCTs shows a clear dose-response curve for intensity of exercise, with effects being stronger for subjects participating in vigorous exercise (CI: -1.10 to -0.38). 

fitness and exerciseThe prevalence of depression is increasing yearly, with around 300 million people worldwide currently being affected by major depressive disorder (MDD)1. There is strong evidence that activation of the innate immune system leads to depressive symptoms, including weight and appetite loss, memory impairment, along with cognitive and social dysfunction2. Therapeutic strategies, such as antidepressant medications, often report suboptimal findings, with roughly 50% of patients not adequately responding3.

Ample research has demonstrated that physical exercise not only improves physical health and reduces disease burden, but also has a positive impact on mental health4. Beneficial effects of exercise are thought to be mediated through the release of “exerkines” including metabolites, proteins, nucleic acids, and hormones5. Furthermore, exercise can change monoamine neurotransmitters, increasing the levels of 5-HT and norepinephrine and reducing cortisol level, leading to alleviation of depressive symptoms6.

Noetel et al. conducted a systematic review and meta-analysis to examine the effects of exercise on depression. Study inclusion consisted of following a randomized controlled trial (RCT) design, with exercise as a treatment for depression, including subjects with clinically diagnosed or self-reported (scored >13 on the Beck depression inventory-II) for MDD. Studies with more than one exercise arm and multifaceted inventions were also included in the analysis. Exercise was defined as “structured and repetitive bodily movements done to improve or maintain components of physical fitness”. Additionally, participants with physical comorbidities like arthritis and subjects with postpartum depression were included.

Data regarding the frequency, intensity, type, and time of each exercise intervention was extracted from each study. The Compendium of Physical Activities was utilized to calculate total energy expenditure as metabolic equivalents of task (METs) min/week. Information on other treatments or control conditions, participants’ age, sex, comorbidities, and baseline severity of depressive symptoms was extracted. Furthermore, data on the duration of the intervention, weekly dose of the intervention, duration between completion of treatment, and measurement were moderated to test the presence of each behavior change technique.

218 RCTs were included in the final analysis. Significant findings of the study are as follows:

  • Compared with active controls, reductions in depression were observed for dance (n=107, 95% CI: -1.36 to -0.56) and moderate reductions for walking or jogging (n=1210, CI: -0.80 to -0.46), yoga (n=1047, CI: -0.73 to -0.36), strength training (n=643, CI: -0.69 to -0.29), mixed aerobic exercises (n=1286, CI: -0.61 to -0.25), and tai chi or qigong (n=343, CI: -0.65 to -0.21).
  • A clear dose-response curve was noted for intensity of exercise, with effects being stronger for subjects participating in vigorous exercise (CI: -1.10 to -0.38). However, light physical activity still provided clinically meaningful effects (CI: -0.82 to -0.33).

Results of the systematic review and meta-analysis show that exercise can be beneficial in reducing severity of depressive symptoms in subjects with MDD, with more significant results noted for vigorous exercise. Study limitations include high publication bias and further RCTs are necessary to better comprehend the therapeutic effects of exercise on depressive symptoms.

Source: Noetel, Michael, Taren Sanders, Daniel Gallardo-Gómez, Paul Taylor, Borja del Pozo Cruz, Daniel Van Den Hoek, Jordan J. Smith et al. “Effect of exercise for depression: systematic review and network meta-analysis of randomised controlled trials.” bmj 384 (2024).

Click here to read the full text study.

Posted April 10, 2024.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

  1. Cui L, Li S, Wang S, et al. Major depressive disorder: hypothesis, mechanism, prevention and treatment. Signal Transduct Target Ther. Feb 9 2024;9(1):30. doi:10.1038/s41392-024-01738-y
  2. Orsolini L, Pompili S, Tempia Valenta S, Salvi V, Volpe U. C-Reactive Protein as a Biomarker for Major Depressive Disorder? Int J Mol Sci. Jan 30 2022;23(3)doi:10.3390/ijms23031616
  3. Kennis M, Gerritsen L, van Dalen M, Williams A, Cuijpers P, Bockting C. Prospective biomarkers of major depressive disorder: a systematic review and meta-analysis. Mol Psychiatry. Feb 2020;25(2):321-338. doi:10.1038/s41380-019-0585-z
  4. Souza PB, de Araujo Borba L, Castro de Jesus L, Valverde AP, Gil-Mohapel J, Rodrigues ALS. Major Depressive Disorder and Gut Microbiota: Role of Physical Exercise. Int J Mol Sci. Nov 28 2023;24(23)doi:10.3390/ijms242316870
  5. Khoury R, Nagy C. Running from stress: a perspective on the potential benefits of exercise-induced small extracellular vesicles for individuals with major depressive disorder. Front Mol Biosci. 2023;10:1154872. doi:10.3389/fmolb.2023.1154872
  6. Zhao JL, Jiang WT, Wang X, Cai ZD, Liu ZH, Liu GR. Exercise, brain plasticity, and depression. CNS Neurosci Ther. Sep 2020;26(9):885-895. doi:10.1111/cns.13385