Childhood endurance fitness linked to reduced long-term depression risk, study finds

A decades-long Australian study reveals that children with better endurance fitness may enjoy lower depression risks in adulthood, highlighting the importance of encouraging physical activity from a young age.

New research suggests that children who are fitter in an endurance sense may carry an advantage that lasts well into adult life: a lower risk of depression decades later. The findings, reported by Newsweek and based on an Australian cohort followed for more than 30 years, add to growing evidence that movement in childhood may shape mental health far beyond the school years.

The study drew on medical data collected in 1985 from more than 1,000 Australian children aged seven to 15, who were later re-examined in adulthood at ages 36 to 49. Their childhood fitness was measured through a 1.6-kilometre run, a standing long jump and a cycle test. In adulthood, participants completed a World Health Organisation interview assessing mental health. Brooklyn Fraser, a research fellow at the University of Tasmania and one of the study’s authors, said that a one-standard-deviation improvement in cardiorespiratory fitness in childhood and adolescence was linked with a 13% lower risk of depression later on.

The clearest pattern appeared in cardiorespiratory endurance, the kind of fitness built through activities that make a child breathe hard and work at sustained effort. According to the researchers, that association was stronger in women than in men. The authors also stressed that the work was observational, meaning it can show links but cannot prove that poor fitness directly causes depression in adulthood.

Experts not involved in the study said the long follow-up period makes the research especially notable. Nicole Avena, a neuroscience professor at the Icahn School of Medicine at Mount Sinai, told Newsweek that many studies look only at adults or follow people for too short a time to understand long-term effects. She said the value of this work lies in its decades-long window on how early fitness may track with later mental health.

There are several possible explanations. Regular aerobic exercise is known to affect inflammatory processes, and chronic inflammation has been associated with depression. Physical activity may also help regulate stress hormones and increase levels of brain-derived neurotrophic factor, a protein that supports the survival and growth of nerve cells. Fraser also suggested that active children may be more likely to remain active as adults, which could help protect mental health over time.

But the researchers and outside clinicians cautioned against reading the findings too simply. Family income, home environment and mental health in early childhood may influence both a child’s fitness and the chance of later depression. Carmel Choi, a clinical psychologist and assistant professor at Harvard Medical School, said cardiorespiratory fitness can act as a broader marker of health, reflecting the work of the heart, lungs and muscles, while also pointing to other health problems that may raise depression risk later in life. She also noted that children from higher-income families may have more access to organised sport, safe places to play and green spaces, as well as greater access to medical and educational support.

The practical message, the authors said, is that childhood fitness is a modifiable factor that may matter for mental health as well as physical health. They argued for daily physical activity, school sport, organised exercise and active play for children across income levels, with particular attention to girls, who often drop out of sport earlier. The next step, they said, is intervention research that actively improves children’s fitness and then tracks whether mental health outcomes change as they grow up.