Disentangling direct and weight-mediated effects of physical activity on health-related quality of life in a 12-month real-world digital lifestyle intervention.

In 30 seconds

This longitudinal study examined physical activity and health-related quality of life (HRQoL) among 1,732 people participating in a 12-month digital lifestyle program; the abstract identifies it as a clinical trial but does not describe randomisation. Estimated mean activity rose from 2.16 to 3.06 MET-h/day (p < 0.001). Greater activity was associated with better scores in most HRQoL domains, with associations largely independent of weight change. For physical functioning and bodily pain, 84.9% and 88.0% of the total associations, respectively, were attributed to the direct pathway rather than mediation through BMI.

Key findings

• Estimated mean physical activity increased from 2.16 to 3.06 MET-h/day (p < 0.001).
• Within individuals, periods of higher-than-usual activity were associated with lower BMI (B = - 0.032, 95% CI - 0.053 to - 0.012).
• Higher activity was associated with better scores in most HRQoL dimensions, including physical and mental component scores.
• The direct pathway accounted for 84.9% of the total association with physical functioning and 88.0% with bodily pain.

Why it matters

The findings suggest that physical activity may relate to quality of life through pathways beyond weight change, including for mental as well as physical HRQoL measures. This distinction is relevant when evaluating lifestyle interventions: weight outcomes alone may not capture all potential quality-of-life associations. The results also support considering activity and weight management as related but distinct intervention goals, while recognising that the observed associations are modest.

What to keep in mind

Follow-up was incomplete, and the individual associations were modest. Physical activity and anthropometric measures relied on self-reported data.