Reacción a "Small and feasible changes in physical activity are associated with lower mortality risk"

This study published in Lancet presents the results of a meta-analysis of published studies analysing the effects of physical exercise on mortality. To this end, the authors selected and analysed individual data from various follow-up studies in Norway, Sweden, the UK and the USA.

The authors describe several interesting findings. The main one is that small increases in vigorous or moderate physical activity appear to reduce all-cause mortality. In addition, they studied two possible scenarios: a “high-risk” scenario in which they studied the effect of physical activity on those who exercise the least, which would maximise the individual benefit in the most inactive people; and a “population” scenario in which the entire population would be targeted, except for the most active 20%, which would have a greater impact in absolute terms.

This study reinforces existing evidence of the benefits of physical activity in reducing mortality, emphasising that modest and realistic changes can bring significant benefits. However, it should be noted that these observational studies have numerous limitations. Among the main ones is the fact that there may be other factors not taken into account by the authors that have confounded the study results (the existence of what is known as “residual confounding”). In addition, the study only analyses all-cause mortality. It would be interesting to expand it by studying specific causes of death and other outcomes, such as the reduction in the incidence of certain diseases or disabilities.