At age 15, the habits Australian teenagers build—or fail to build—can reshape the trajectory of their health for decades to come. A University of Adelaide study tracking thousands of young Australians has revealed which groups are most likely to slip through the cracks during the critical transition from high school to university and work, missing out on the protective benefits that regular exercise provides.
The research matters because the stakes are substantial. Sustained recreational exercise in youth improves fitness, strengthens physical health, boosts self-esteem, reduces psychological distress, and establishes patterns that dramatically lower disease risk in adulthood. Yet Australia's young people are exercising less regularly with each passing year after leaving secondary school, according to data from the Longitudinal Survey of Australian Youth (LSAY), a long-running national study that follows cohorts as they navigate early adulthood.
The findings expose unexpected blind spots in our understanding of who struggles most. Females face significant structural and cultural barriers—reduced opportunities, lower access to diverse sports, and divergent parental and cultural expectations that discourage participation. But the researchers were surprised to discover that academic high achievers also fall into the at-risk category, a pattern that highlights how intense academic pressure can crowd out time and energy for self-care during formative years. Low self-efficacy, reluctant exercisers, and young people experiencing socioeconomic disadvantage round out the vulnerable groups.
"It is well known that sustained regular exercise in young people improves fitness, physical health, self-esteem, reduces distress and sets up long-term patterns that reduce disease risk in adulthood," says Associate Professor Oliver Schubert from the University of Adelaide's Adelaide Medical School and Northern Adelaide Local Health Network. "There seems to be a critical period in people's teens, around the age of 15, to establish these behaviours."
Dr Julie Morgan, lead author of the study and Clinical Associate Lecturer at the University of Adelaide's Discipline of Psychiatry, emphasizes that the gender gap involves more than simple preference. "The disadvantage experienced by females is influenced by reduced opportunity, lower access, and lack of sports diversity, but also divergent parental and cultural expectations, stereotypes, and role models," she explains. Psychological factors like perceived sports competency also play a role.
The strength of this research lies in its methodology. Unlike earlier cross-sectional studies that capture a single moment in time, the LSAY's high follow-up rate and large sample size allowed researchers to track trajectory-based patterns over years, producing more robust evidence for policy development. Jana Bednarz, senior statistician at the University of Adelaide, conducted the longitudinal modelling analyses that revealed these patterns with clarity previously impossible to achieve.
The researchers call for early intervention. Secondary schools, particularly in final years when academic pressure intensifies, have a key role to play. Universities and vocational institutions should run programs that actively support physical activity. But responsibility extends beyond education: state governments and local councils must ask whether current leisure infrastructure meets young people's needs, and funding for grassroots community sport across gender and socioeconomic lines is critical.
Identifying these at-risk groups by age 15 offers a real opportunity to shift trajectories before habits calcify. The window is narrow, but it is open.