Depression among adolescents has become one of the most pressing public health concerns of the past decade, and researchers around the world have been searching for modifiable factors that could help protect young people’s mental health. A new large-scale study from China now adds a compelling piece to that puzzle: the physical fitness of a teenager’s body, measured across several distinct components, appears to be meaningfully associated with the state of their mind. The research, published in BMC Public Health, analyzed more than ten thousand Chinese adolescents and found that those with the lowest overall health-related physical fitness were substantially more likely to report depressive symptoms than their fittest peers.
The investigation was conducted between August 2021 and April 2022 and drew participants from five Chinese cities spanning considerable geographic and cultural diversity: Shanghai and Suzhou in the east, Kunming in the southwest, Urumqi in the far northwest, and Changsha in central China. In total, 10,327 adolescents aged 12 to 17 years took part. This age range captures the middle school and early high school years, a developmental window in which depressive symptoms often first emerge and in which academic pressure, social change, and biological maturation all converge. The study received ethics approval from the East China Normal University Committee on Human Research Protection, and written informed consent was obtained from both the participants and their parents, with participant names coded to protect privacy.
What sets this study apart from much of the existing literature is its focus on health-related physical fitness as a whole, rather than on a single dimension such as cardiorespiratory endurance. Previous research has suggested that higher cardiorespiratory fitness may ameliorate depressive symptoms in adolescents, but the relationship between depression and the broader fitness profile has remained unclear. To capture that broader profile, the researchers administered a battery of physical tests: measurements of height and weight to calculate body mass index, a standing long jump to assess lower-body explosive strength, a thirty-second sit-up test to gauge muscular endurance, the twenty-meter shuttle run test to estimate cardiorespiratory fitness, and a sit-and-reach test to evaluate flexibility. Together, these measurements were combined into a composite score known as the health-related physical fitness Z-score, or HPF-Z, which summarizes each participant’s overall fitness relative to the group.
Depressive symptoms, meanwhile, were evaluated using the Center for Epidemiological Studies Depression Scale, a widely used and well-validated screening instrument known as the CES-D. Rather than diagnosing clinical depression, the scale captures the frequency of symptoms such as low mood, loss of interest, and feelings of hopelessness over the preceding week, providing a snapshot of psychological distress in the general population. The researchers then employed a series of statistical techniques, including the Kruskal-Wallis H test, t-tests, chi-square tests, and binary logistic regression, to examine how fitness levels related to the likelihood of reporting depressive symptoms after accounting for other variables.
The headline finding is stark. The overall prevalence of depressive symptoms among the adolescents studied was 28.6 percent, but that figure concealed a pronounced gender gap: 24.2 percent of boys reported depressive symptoms compared with 33.1 percent of girls, meaning roughly one in three girls in the sample showed signs of psychological distress. This gender disparity echoes patterns documented in adolescent mental health research worldwide and underscores that girls in this age group may be a particularly vulnerable population.
After adjusting for covariates, the association between fitness and depression emerged clearly. Adolescents in the lowest grade group of the overall HPF-Z score had a prevalence of depressive symptoms 1.41 times higher than those in the highest grade group, with an odds ratio ranging from 1.244 to 1.602 and a p-value below 0.001. In other words, the least fit teenagers were roughly forty percent more likely to report depressive symptoms than the fittest, even after statistical adjustment for other factors. The pattern held when each fitness component was examined individually. Those in the lowest group for the standing long jump showed depressive symptom prevalence 1.35 times higher than the top group; for thirty-second sit-ups, the figure was 1.25 times; for the twenty-meter shuttle run test, also 1.25 times; and for the sit-and-reach test of flexibility, 1.18 times. Each of these differences was statistically significant, with p-values ranging from below 0.001 to 0.015.
Body composition told a complementary story. Adolescents in the normal weight group had a prevalence of depressive symptoms 0.85 times that of the obesity group, meaning they were about fifteen percent less likely to report symptoms. The researchers also detected significant dose-response trends: the prevalence of depressive symptoms decreased as body mass index decreased, with a trend p-value of 0.009, and decreased as performance improved on the standing long jump, thirty-second sit-ups, twenty-meter shuttle run, and sit-and-reach tests, with trend p-values of less than 0.001, 0.001, 0.001, and 0.007 respectively. Taken together, the results indicated that body mass index had a positive predictive effect on depressive symptoms, meaning higher BMI predicted more symptoms, whereas the overall fitness Z-score and each individual fitness item negatively predicted depressive symptoms, meaning better fitness predicted fewer symptoms.
From a technical standpoint, the strength of this study lies in its scale and its multi-component assessment. With more than ten thousand participants drawn from five cities, the statistical power to detect associations is considerable, and the use of objective physical tests rather than self-reported fitness removes a common source of bias in this literature. The shuttle run test, in particular, is a well-established field protocol for estimating cardiorespiratory fitness in youth, while the standing long jump and sit-up tests capture neuromuscular strength and endurance that are often overlooked in studies focused solely on aerobic capacity. The inclusion of flexibility, measured by the sit-and-reach test, is unusual in mental health research, and the finding that even this component showed a significant association suggests that the fitness-depression link may not be confined to any single physiological pathway.
That said, the study’s design imposes important limits on interpretation. Because the data are cross-sectional, collected at a single point in time, the findings demonstrate association rather than causation. It is possible that low fitness contributes to depressive symptoms, but it is equally plausible that depression leads to reduced physical activity and declining fitness, or that shared underlying factors, such as socioeconomic circumstances, sleep, or academic stress, influence both. The binary logistic regression adjusted for covariates, but no observational study can rule out residual confounding entirely. Longitudinal follow-up and intervention studies would be needed to establish whether improving fitness actually reduces depressive symptoms, and the authors’ own framing of BMI and fitness as predictors should be read in this associative sense rather than as proof of causal direction.
Nevertheless, the public health implications are significant. Nearly three in ten adolescents in the sample reported depressive symptoms, a burden that carries consequences for academic performance, social development, and long-term mental health. If physical fitness is indeed one modifiable lever, school-based physical education, active commuting, and community sports programs become potential channels for prevention, particularly for girls, whose symptom prevalence in this study was markedly higher. The composite HPF-Z approach also offers a practical message: no single test determines the outcome, and improvements across any component, from endurance to strength to flexibility, were each associated with lower symptom prevalence. As youth mental health services worldwide remain stretched far beyond capacity, evidence that the gymnasium and the playing field may play a role alongside the clinic is a finding worth taking seriously, even as researchers work to confirm whether the relationship is causal and to identify the biological and psychological mechanisms that might connect a fitter body to a healthier mind.
Subject of Research: The association between health-related physical fitness and depressive symptoms in Chinese adolescents
Article Title: Depressive symptoms in Chinese adolescents: the role of health-related physical fitness
Article References: Zhang, T., Guo, Y., Li, M., Liu, Y., Sun, P., Yin, X., & Zhang, F. (2026). Depressive symptoms in Chinese adolescents: the role of health-related physical fitness. BMC Public Health. https://doi.org/10.1186/s12889-026-29840-6
Image Credits: AI Generated
DOI: 10.1186/s12889-026-29840-6
Keywords: adolescent health, depression, physical fitness, cardiorespiratory fitness, body mass index, mental health, CES-D, China, public health, obesity, exercise, BMC Public Health
News Source: Glenn Wilkins. (October 12, 2026). Physical Fitness Linked to Lower Depression Risk in Chinese Teens, Study of 10,000 Finds. Scienmag.
