Examining the Effect of Physical Activity and Depressive Symptoms in Adolescents
November 1, 2023 7 minutes read
By Ellen Feldman, MD
Altru Health System, Grand Forks, ND
Summary Points
- This meta-analysis synthesized findings from 21 studies, encompassing 2,441 participants, to examine diverse physical interventions for pediatric populations with depressive symptoms.
- While the intervention showed a statistically significant effect (P = 0.004) in short-term studies compared to controls, the differences became non-significant in the four studies that conducted follow-up evaluations.
- The most pronounced reductions in depressive symptoms were observed in children older than 13 years of age and in participants presenting with the highest symptom severity and depression diagnosis.
SYNOPSIS: In a robust meta-analysis of 21 studies, physical activity interventions showed a significant short-term benefit for children and adolescents with depressive symptoms, particularly in those aged 13 years and older and in participants with a diagnosis of depression.
SOURCE: Recchia F, Bernal JDK, Fong DY, et al. Physical activity interventions to alleviate depressive symptoms in children and adolescents: A systematic review and meta-analysis. JAMA Pediatr 2023;177:132-140.
Often regarded as the “forefather” of Western medicine, Hippocrates may have been the first physician to recognize the central role of exercise in the treatment of disease.1 Modern research has since robustly affirmed the connection between physical activity and decreased morbidity and mortality across at least 27 diverse physical and mental health conditions.2
Several meta-analyses consistently have indicated that physical activity alleviates depressive symptoms in adults. Consequently, multiple international guidelines now advocate for this intervention.3,4 Yet research focusing on younger demographics is not as strong.
Given a concerning global prevalence rate of 12.9% pre-pandemic and the risk of severe outcomes when not treated, childhood and adolescent depression clearly is a critical health challenge. Current U.S. guidelines endorse psychotherapeutic and/or psychopharmacologic treatments for depression in younger age groups, but national and international surveys reveal that only a small fraction of children receive disorder-specific or specialist care.5,6
In formulating this study, Recchia et al spotlighted the widespread accessibility of physical activity as an intervention, comparing it favorably over psychotherapy or psychopharmacology in terms of global reach. They also stressed the reduced stigma tied to this intervention and its potential for advantageous side effects.
Earlier meta-analyses, while highlighting the potential of physical activity in managing depressive symptoms in youth, suffered from limited scope and the exclusion of prevalent comorbid conditions.7 Recchia et al took a more comprehensive approach in their meta-analysis, incorporating more expansive studies and including studies that encompassed common comorbidities associated with depression, such as attention-deficit disorder, anxiety, diabetes, and obesity.
Results
Of the 21 studies meeting inclusion criteria, 17 were randomized clinical trials. In all, 2,441 participants were involved (47% male), with a mean age at baseline of 14 years old. A slight majority of these studies included children with co-existing diagnoses.
On average, the duration of the study period was 22 weeks with physical activity lasting 50 minutes. While most sessions were supervised, not all were. In terms of frequency, eight of the studies required physical activity three days per week while other studies ranged from two to five days weekly. Notably, the data were sourced from a global research pool, including studies from China, Chile, Germany, Iran, the United Kingdom, and the United States. All studies included in the meta-analysis used validated depression scales to measure outcomes.
In most studies, an aerobic “dose” of physical activity was reported. However, the type of activities varied greatly and included equipment-based exercise in some studies. Physical activity was integrated into a broader, multimodal intervention, while it stood alone as a single treatment in the remainder of the studies.
To determine the effect size of these interventions, Recchia et al employed Hedges’ G — a statistical measure used to estimate the standardized difference between two populations means. Conventionally, Hedges’ G values of 0.2, 0.5, and 0.8 represent small, medium, and large effect sizes, respectively.8 In the context of this study, a negative differential indicates a beneficial reduction in depression scores.
Table 1 delineates some of the main results of this study. The mean effect size of differentiating physical intervention from the control in the pooled studies was small but significant with a Hedges’ G = -0.29 (95% confidence interval [CI], -0.47 to -0.10; P = 0.004.) However, this effect size became more pronounced when focusing solely on participants aged 13 years and older or those diagnosed with depression or any mental disorder.
Table 1. Summary of Results From Meta-Analysis of Physical Activity as an Intervention for Depressive Symptoms |
||
| Hedges’ G | P Value | |
Pooled studies |
-0.29 |
0.004* |
Pooled studies |
-0.39 |
0.14 |
Adolescents only |
-0.44 |
0.003* |
Children only |
-0.05 |
0.44 |
Participants with a diagnosis of depression |
-0.73 |
0.004* |
Participants with mental illness |
-0.74 |
< 0.001* |
Participants with physical illness |
-0.22 |
0.31 |
*Statistically significant value CI: confidence interval |
||
Only four studies looked at sustained remission of depressive symptoms (six to 48 weeks post-study). None of these studies showed a significant statistical association of physical activity with relief of depressive symptoms at the time of follow-up.
Commentary
In an editorial response to the Recchia et al meta-analysis, Dr. Eduardo Bustamante aptly declared, “Physical activity is remarkable medicine.” Citing this study as a potential turning point for the field, Dr. Bustamante noted the rigor and wide reach of the study as well as the potential for significant effect on the treatment of depressive symptoms in the younger generation.9
Recchia et al acknowledged the need for further research in the field. They stressed the importance of delving deeper into the mechanisms driving the antidepression effect of physical activity and understanding requirements for optimal dose, frequency, and intensity of physical activity. The team speculated that young children were not as affected by physical intervention because their inherent baseline physical activity is high compared to older peers; this also is an area to understand better with future studies.
Another limitation affecting broad applicability of these findings is the considerable heterogeneity of methodologies employed across studies. This includes differences in the specific depression scales used for outcome evaluation as well as variations in the type, frequency, and documentation of physical activity. A more uniform approach in subsequent investigations will enhance clarity and contribute further to this field.
It is curious that the four long-term studies did not show a significant effect of physical activity on depressive symptoms. This may reflect limited sample size, but it also may imply that continued encouragement of physical activity is necessary to have continued effect. Regrettably, these follow-up studies did not document post-study activity levels, but such information may help to clarify this point in the future.
One question, posed by Dr. Bustamante as well as others, is what is the best strategy to champion physical activity among youth? While this may be a question for public health, it holds clear clinical significance for the integrative provider treating depressive symptoms in children and/or adolescents. This may be the next direction for research and investigation in this area.
This groundbreaking work may serve as both a beacon and a call to action. While emphasizing the potential therapeutic benefits of physical activity especially during teen years, it also underscores the vast terrain yet to be explored. As we recognize the importance of physical activity in mental health, the responsibility lies on many of us — researchers, clinicians, public health officials, communities, and families — to foster environments that support and sustain these beneficial activities for our youth.
References
- Moore GE. The role of exercise prescription in chronic disease. Br J Sports Med 2004;38:6-7.
- Piercy KL, Troiano RP, Ballard RM, et al. The Physical Activity Guidelines for Americans. JAMA 2018;320:2020-2028.
- Pearce M, Garcia L, Abbas A, et al. Association between physical activity and risk of depression: A systematic review and meta-analysis. JAMA Psychiatry 2022;79:550-559.
- Hess CW, Karter J, Cosgrove L, Hayden L. Evidence-based practice: A comparison of International Clinical Practice Guidelines and current research on physical activity for mild to moderate depression. Transl Behav Med 2019;9:703-710.
- Racine N, McArthur BA, Cooke JE, et al. Global prevalence of depressive and anxiety symptoms in children and adolescents during COVID-19: A meta-analysis. JAMA Pediatr 2021;175:1142-1150.
- Walter HJ, Abright AR, Bukstein OG, et al. Clinical practice guideline for the assessment and treatment of children and adolescents with major and persistent depressive disorders. J Am Acad Child Adolesc Psychiatry 2023;62:479-502.
- Wang X, Cai Z-D, Jiang W-T, et al. Systematic review and meta-analysis of the effects of exercise on depression in adolescents. Child Adolesc Psychiatry Ment Health 2022;16:16.
- Glen S. Hedges’ G: Definition, formula. Statistics How To. https://www.statisticshowto.com/hedges-g/
- Bustamante EE, Santiago-Rodríguez ME, Ramer JD. Unlocking the promise of physical activity for mental health promotion. JAMA Pediatr 2023;177:111-113.
In a robust meta-analysis of 21 studies, physical activity interventions showed a significant short-term benefit for children and adolescents with depressive symptoms, particularly in those aged 13 years and older and in participants with a diagnosis of depression.
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