Boosting physical fitness in youth linked to lower mental disorder risks

By Priyanjana Pramanik, MSc.May 1 2024Reviewed by Susha Cheriyedath, M.Sc.

In a recent study published in the journal JAMA Pediatrics, researchers investigated the association between levels of physical fitness and mental disorder risks among children and adolescents over a decade.

They found that better cardiorespiratory fitness, muscular endurance, and muscular power were associated with reduced risks of anxiety, depression, and Attention-Deficit/Hyperactivity Disorder (ADHD), suggesting the potential protective role that physical fitness can play in preventing the onset of mental disorders in this demographic.

Study: Physical Fitness and Risk of Mental Disorders in Children and Adolescents. Image Credit: matimix / Shutterstock

Background

The World Health Organization reports that mental health problems affect one in seven individuals aged 10 to 19 years, with increasing prevalence worldwide.

Enhancing mental health involves identifying protective factors against these challenges, with physical fitness emerging as a significant consideration.

Previous research involving children and adolescents indicates a positive link between physical fitness and mental health, albeit with limitations such as study design and inconsistent correlations.

About the study

A study conducted in Taiwan aimed to address this gap by examining the relationship between levels of physical fitness and the risk of developing mental disorders in the long term, including anxiety, depression, and ADHD, utilizing a longitudinal approach with a sizeable national-level cohort.

Its objective was to elucidate the potential role of physical fitness as an indicator for identifying individuals at risk of developing mental disorders.

The study utilized retrospective data obtained from the National Student Fitness Tests Database (NSFTD) and the National Health Insurance Research Database (NHIRD) in Taiwan.

From the NHIRD, researchers obtained medical claims data, while the NSFTD compiled data from annual physical fitness assessments and included body mass index (BMI) records of students.

Two distinct cohorts were constructed: anxiety and depression (ANX-DEP) and ADHD, spanning from January 1, 2009, to December 31, 2019. Participants were students aged 10 or 11 years with a minimum follow-up period of three years.

Exclusion criteria included prior cerebral palsy diagnosis and previous diagnoses of anxiety, depression, or ADHD. Physical fitness measures comprised an 800-meter run (cardiorespiratory fitness [CF]), bent-leg curl-ups to test muscular endurance [ME], standing broad jumps to assess muscular power [MP], and sit-and-reach tests that assessed flexibility fitness [FF].

The primary outcome was the clinical diagnosis of a mental disorder after the index date and supported by claims data. Researchers used multivariable Cox proportional hazards models to assess the relationship between physical fitness and risk of mental disorder, with sensitivity analyses conducted to ensure robustness.

Findings

The study analyzed data from nearly four million Taiwanese students, constructing two cohorts focusing on ADHD and ANX-DEP, with a median age of 10.6 years.

Participants underwent various fitness tests, with females and males achieving mean scores of 5.1 and 4.9 minutes in CF, respectively. Lower fitness levels were associated with higher risks of mental disorders.

For instance, in the best-performing quartile of CF, female participants had a cumulative ADHD incidence of 0.18%, compared to 0.46% in the lowest quartile. Similar patterns were observed in male participants, indicating a dose-dependent link between physical fitness and mental disorder risks.

Multivariable Cox proportional hazards models revealed significant associations between improved physical fitness and reduced risks of anxiety, depression, and ADHD. For example, a half-minute decrease in 800-meter run times (CF) was correlated with a 3% to 8% decrease in mental disorder risk.

Similarly, enhancements in ME, MP, and FF were associated with decreased risks of various mental disorders, with differential effects observed between genders.

Sensitivity analyses supported the robustness of these findings, confirming a dose-response association between higher physical fitness levels and lower mental disorder risks.

Additionally, improvements in fitness over time were linked to reduced incidence of mental disorders, emphasizing the importance of fitness enhancement programs in promoting mental health among children and adolescents.

Conclusions

The study, involving 1.9 million children and adolescents, found that lower levels of physical fitness, especially in cardiorespiratory and muscular fitness, were independently linked to higher incidences of anxiety disorders, depressive disorders, and ADHD.

This association persisted even after accounting for potential confounding factors like demographics, BMI, and psychiatric comorbidities. The research highlighted how different fitness components were associated with mental disorders, with notable sex differences observed.

While cardiorespiratory fitness showed the strongest association with mental health, the relationship between flexibility and mental disorders was less significant.

The study emphasized the importance of considering sex as a pivotal factor in examining the link between physical fitness and mental disorders, and it provided robust evidence of an inverse association between physical fitness and ADHD risk.

The study's strengths included its large, nationwide cohort and standardized physical fitness assessments. Its limitations included the observational nature of the study and the lack of data on pubertal status and other health-related behaviors.

Overall, the research underscores the potential of targeted programs to promote physical fitness as a primary preventive intervention against mental disorders in children and adolescent individuals.