- New research reaffirms ancient wisdom: Exercise promotes both physical well-being and mental health.
- Physical activity helps the body stay healthy. Exercise also has antidepressant effects that can alleviate depression.
- A meta-analysis of 21 studies shows that physical activity interventions may relieve adolescents' depressive symptoms.
A recently published systematic review and meta-analysis of almost two dozen different studies conducted over the past four decades shows that physical activity interventions can significantly alleviate depressive symptoms in adolescents during their teenage years. This peer-reviewed paper (Recchia et al., 2023) was published in JAMA Pediatrics.
In an editorial comment (Bustamante et al., 2023) that accompanies this JAMA Pediatrics meta-analysis, the authors start by saying, "Physical activity is remarkable medicine." Their words echo the timeless wisdom of Hippocrates, who famously said, "Walking is the best medicine." Similarly, in 55 A.D., the Roman poet Juvenal coined the phrase mens sana in corpore sano (a healthy mind in a healthy body), which sums up the bidirectional link between physical well-being and mental health.
In their editorial, Eduardo Bustamante and colleagues note that all the science-based evidence about exercise's antidepressant effects that's been unearthed in the 21st century is technically "new." However, they clarify this newness by writing: "These new benefits are, of course, not new in the sense that active people in the past did not receive them; rather, they are new in the sense that sufficient evidence arose in meta-analyses to affirm them."
My lived experience reaffirms evidence-based findings on physical activity's antidepressant effects.
During my adolescence in the 1980s—long before I even knew what scientific "meta-analyses" were—I stumbled on the ability of physical activity to alleviate teenage depression. My self-discovery that I could use exercise as integrative medicine to ease my depressive symptoms happened in the summer of 1983, when I was 17.
For me, the inspiration to start working out was sparked by Flashdance and the movie's theme song. When Irene Cara passed away in November 2022, I paid tribute to her by going for a long jog and playing the extended remix version of this anthem non-stop. The lyrics to this song helped me overcome my fear and crippling anxiety as a clinically depressed teen. Decades later, hearing this song still fills me with hopefulness and gives me the oomph to face uphill battles.
Forty years ago, in June 1983, when "Flashdance... What a Feeling" was first released, I was a hopeless and dysphoric teen. The music video for this song was in heavy rotation on MTV at the time and provided daily motivation to lace up my sneakers and go for a 30-minute jog at moderate intensity. I ran almost every day from June to September; my depressive symptoms gradually dissipated during these three months.
My lived experience of having a "physical activity intervention" alleviate depressive symptoms during adolescence isn't unique. The latest (2023) meta-analysis of 21 studies involving 2,441 children and adolescents shows that, after age 13, teens who start working out regularly tend to have much lower rates of depression than their age-matched peers who don't work out.
Additionally, the findings from this meta-analysis suggest that the antidepressant benefits of physical activity really take hold after about 12 weeks of sticking with an exercise routine.
Goldilocks zone: Too much or too little exercise doesn't alleviate depression like a medium dose that's "just right."
The meta-analysis by Recchia et al. reaffirms that there's an inverted-U "Goldilocks zone" between too much and too little exercise that appears to have the most potent mental health benefits. In general, this sweet spot seems to be about 30-60 minutes of moderate-intensity cardio most days of the week. However, accumulating evidence suggests that shorter durations of high-intensity interval training (HIIT) can also provide antidepressant effects in less time.
Nevertheless, pinpointing the exact "dose" (duration/frequency/intensity) of exercise that most effectively alleviates depressive symptoms is unclear and remains a holy grail-like riddle for researchers. "The association with physical activity parameters such as frequency, duration, and supervision of the sessions remains unclear and needs further investigation," Francesco Recchia and co-authors explain.
Correlation does not imply causation.
It's worth noting that all of the studies in Recchia et al.'s systematic review and meta-analysis are correlative. Because correlation doesn't imply causation, it's impossible to be 100 percent certain that physical activity was the primary factor that caused teens who exercised to be less depressed. That said, the focus of this meta-analysis was on "physical activity interventions" that were prescribed to one group of children and adolescents while others were in a control group, which boosts the reliability of the findings.
In most of the 21 studies included in this systematic review, adults supervised and coached study participants in the exercise groups, which helped researchers avoid the chicken-or-the-egg conundrum found in other cross-sectional studies that aren't based on physical activity interventions and rely on questionnaires that ask people to self-report how often they exercise and then assess their depressive symptoms.
In exercise studies not based on a closely monitored "intervention," it's almost impossible to know how much the results are skewed by the fact that people who are less depressed to begin with are probably more likely to exercise or if the exercise itself is causing people to be less depressed.
Stick with it! Exercise's antidepressant effects may take 12 weeks to kick in.
In their conclusion, Recchia et al. write, "Physical activity interventions may be used to reduce depressive symptoms in children and adolescents. Greater reductions in depressive symptoms were derived from participants older than 13 years and with a mental illness and/or depression diagnosis."
Anecdotally, as a teenager living with major depressive disorder (MDD), I watched my depressive symptoms dissolve over 12 weeks once I started jogging for 30 minutes at moderate intensity most days of the week. I know from lived experience that, over time, physical activity can help to alleviate depression during adolescence, but these antidepressant effects may not be instantaneous.
Hopefully, future research will provide insights on the optimal dose of exercise that most effectively unlocks physical activity's ability to improve mental health at every stage of the human lifespan.
Francesco Recchia, Joshua D. K. Bernal, Daniel Y. Fong, Stephen H. S. Wong, Pak-Kwong Chung, Derwin K. C. Chan, Catherine M. Capio, Clare C. W. Yu, Sam W. S. Wong, Cindy H. P. Sit, Ya-Jun Chen, Walter R. Thompson, Parco M. Siu. "Physical Activity Interventions to Alleviate Depressive Symptoms in Children and Adolescents: A Systematic Review and Meta-Analysis." JAMA Pediatrics (First published: January 03, 2023) DOI: 10.1001/jamapediatrics.2022.5090
Accompanying Editorial Comment: Eduardo E. Bustamante, María Enid Santiago-Rodríguez, Jared D. Ramer. "Unlocking the Promise of Physical Activity for Mental Health Promotion." JAMA Pediatrics (First published: January 03, 2023) DOI: 10.1001/jamapediatrics.2022.5096