Physical activity and longevity: how to move closer to causal inference

Kujala provides an insightful review contesting epidemiological findings that increased physical activity (PA) lengthens the life span,1 arguing that intervention (randomised controlled trial (RCT) and experimental) studies do not support PA causing a reduced risk of death and highlighting several limitations in previous observational studies that may have led to spurious conclusions. The review coincides with the publication of findings from...