Personally, my favorite explanation for why a more sound body leads to a more sound mind is pure chemistry, the hormonal effects of exercise on the brain. But here’s a nice new study out in the journal Clinical Psychological Science that found a dual explanation in thousands of Dutch teen girls: Improved self-image and improved social life. From the press release:
Karin Monshouwer of the Trimbos Institute in the Netherlands and colleagues at Trimbos and VU University Medical Center specifically wanted to examine two existing explanations for the link between exercise and mental health. The self-image hypothesis suggests that physical activity has positive effects on body weight and body structure, leading to positive feedback from peers and improved self-image, and ultimately improving mental health. The social interaction hypothesis, on the other hand, holds that it’s the social aspects of physical activity – such as social relationships and mutual support among team members – that contribute to the positive effects of exercise on mental health.
Monshouwer and her colleagues surveyed over 7000 Dutch students, ages 11 to 16. The adolescents completed validated surveys aimed at assessing their physical activity, mental health problems, body weight perception, and participation in organized sports. The researchers also gathered data on the adolescents’ age, gender, and socioeconomic status; whether they lived at home with their parents; and whether they lived in an urban area.
The researchers found that adolescents who were physically inactive or who perceived their bodies as either “too fat” or “too thin” were at greater risk for both internalizing problems (e.g., depression, anxiety) and externalizing problems (e.g., aggression, substance abuse). Adolescents who participated in organized sports, on the other hand, were at lower risk for mental health problems.
Confirming both the self-image hypothesis and the social interaction hypothesis, adolescents’ body weight perception (i.e., “too heavy,” “good,” or “too thin”) and sports club membership each partially accounted for the relationship between physical activity and mental health, even after taking adolescents’ backgrounds into account.