Least-fit Chinese teenagers 41% more likely to report depressive symptoms

A study of more than 10,000 Chinese adolescents found that those in the lowest fitness group were substantially more likely to report depressive symptoms, although the research cannot establish cause and effect.

A large study of more than 10,000 Chinese adolescents suggests that physical fitness is closely tied to mental well-being, with the least fit teenagers far more likely to report depressive symptoms than their fitter peers. The research, published in BMC Public Health, adds weight to a growing body of evidence that exercise-related factors may matter not only for physical health but also for emotional resilience during the teenage years.

The study followed 10,327 young people aged 12 to 17 in five cities across China between August 2021 and April 2022. Researchers assessed health-related physical fitness using objective measures rather than self-report: body mass index, standing long jump, 30-second sit-ups, a 20-metre shuttle run and the sit-and-reach test for flexibility. They then compared those results with depressive symptoms measured using the Centre for Epidemiological Studies Depression Scale, a screening tool that captures recent signs of low mood and distress rather than diagnosing clinical depression.

The overall rate of depressive symptoms was 28.6%, but the burden was unevenly distributed. Girls reported symptoms more often than boys, at 33.1% compared with 24.2%, a gap that mirrors wider patterns in adolescent mental health research. After accounting for other factors, teenagers in the lowest fitness group were about 41% more likely to report depressive symptoms than those in the highest group. Similar associations appeared across each of the individual fitness measures, from muscular endurance and explosive strength to aerobic capacity and flexibility. Higher body mass index also tracked with more depressive symptoms, while better performance on the physical tests consistently aligned with fewer symptoms.

The findings fit with other recent Chinese studies pointing in the same direction. A smaller Beijing-based study published in Neuropsychiatric Disease and Treatment found that cardiopulmonary fitness was negatively correlated with depressive states, while a separate paper in Frontiers in Pediatrics reported that physical activity was linked to better health-related quality of life, with sleep and mood helping to explain part of that relationship. Another study in Scientific Reports followed Chinese adolescents and young adults over several years and found that insufficient physical activity and depressive symptoms often co-occurred, while research in BMC Public Health has also linked sedentary behaviour, sleep disturbance and low activity levels with depression risk.

Even so, the new study cannot prove that poor fitness causes depression, or that improving fitness will automatically lift mood. Because the data were collected at one point in time, the relationship could run in either direction: low fitness may contribute to depressive symptoms, but depression may also reduce motivation, activity and physical performance. Shared pressures such as school stress, sleep problems and family circumstances could also shape both. What the study does show, however, is that physical fitness may be a meaningful and modifiable marker of adolescent mental health, and one that schools and families may be able to address through more active routines, sports participation and broader support for healthy habits.