The Need for Upper Limits in Physical Activity Guidelines: A Narrative Review

Physical activity (PA) guidelines establish minimum thresholds for health benefits but lack upper limits. Regular PA is associated with reduced all-cause mortality, but a growing body of evidence indicates a J- or reverse J-shaped relationship, suggesting that excessive exercise may not provide additional longevity benefits and may even pose health risks. This narrative review synthesizes findings from cohort studies and meta-analyses examining the dose-response relationships between total PA and resistance exercise training (RET) and all-cause mortality. The greatest reduction in mortality risk coincides with 2,000–3,000 metabolic equivalents minutes/week of total PA, including 40–60 minutes/week of RET. Exceeding these levels is not associated with further improvements in survival risk and may be associated with increased mortality risk, potentially through adverse cardiovascular adaptations including myocardial fibrosis and arterial stiffness. Given the rising engagement in aerobic and muscle-strengthening exercise, public health recommendations should include safe upper thresholds alongside existing minimum targets.