Longitudinal impact of physical activity on visceral adiposity, recovery, and costs in severe mental disorders: a 15-month quasi-experimental study in a community setting

Purpose Severe mental disorders (SMD) are associated with marked physical comorbidity, premature mortality, and substantial healthcare utilisation. Although physical activity (PA) is increasingly recommended as an adjunctive intervention, long-term real-world evidence linking PA participation with both clinical outcomes and healthcare costs in community psychiatric settings remains limited. This study examined longitudinal associations between engagement in a structured PA programme and health-related and economic outcomes among individuals with SMD. Methods A 15-month quasi-experimental longitudinal study was conducted with 156 adults diagnosed with SMD receiving routine community mental health care. Participants either enrolled in a structured PA programme (n = 78) or received treatment as usual (TAU; n = 78), with groups matched on key demographic and clinical variables. Outcomes included body composition, physical fitness, mental well-being (WEMWBS), health-related quality of life (WHOQOL-BREF), and direct healthcare costs derived from psychiatric hospitalisations and psychotropic medication use. Results Over the 15-month follow-up, participation in the PA programme was associated with greater improvements in cardiorespiratory fitness, body composition—including reductions in visceral adiposity—and psychological well-being compared with TAU (p < .001). Participants in the PA group also exhibited higher gains in quality of life and more favourable behavioural profiles. In parallel, lower observed direct healthcare expenditures were recorded in the PA group, primarily reflecting reduced psychiatric hospitalisation and medication costs, although cost analyses were exploratory in nature. Conclusion In a real-world community setting, sustained engagement in structured physical activity was associated with clinically meaningful improvements in physical and psychological outcomes among individuals with SMD, alongside lower healthcare utilisation over time. These findings support the potential role of structured PA as a scalable component of recovery-oriented mental health services, while highlighting the need for controlled trials to confirm causality and formally evaluate cost-effectiveness.