Physical Activity Correlates With a Sizable Difference to Late Life Mortality
Epidemiological studies consistently show a sizable difference in mortality rates between those who exercise regularly and those who do not. Clearly at some point aging forces a reduction in activity, and those more impacted by aging will tend to have a greater mortality risk. But animal studies show that exercise does in fact slow aging; it doesn't have much of an effect on maximum life span in mice, but it does reduce mortality and postpone frailty and mortality to lengthen median life span. How much of the observed correlation in humans is due to causation in one direction versus the other is up for debate, but the consensus is that physical activity is beneficial.
Long-term causal evidence comparing different physical activity patterns and mortality outcomes is needed. Using observational data to emulate a randomized controlled trial, this study compared different physical activity patterns over 15 years in relation to mortality from all causes, cardiovascular disease (CVD) and cancer in 11,169 mid-aged women in the Australian Longitudinal Study on Women's Health.
Two emulated interventions were compared against consistent non-adherence (control) to World Health Organization moderate-to-vigorous physical activity (MVPA) recommendations during the 15-year 'exposure period': (1) consistent adherence to recommendations (at least 150 min/week) over 15 years (2001-2016; women were 50-55-65-70 years); and (2) starting to meet the recommendations at age 55, 60, or 65 years.
Mortality outcomes that occurred between surveys (women were 53-58 at the first survey and 68-73 years at the last survey), were ascertained from Australian death registries. Comparing consistent adherence to MVPA recommendations with consistent non-adherence, there was evidence (Bayes factor [BF] = 5.71) for a protective effect for all-cause mortality (risk ratio [RR]: 0.50; risk difference [RD]: -5.2%). Findings for cardiovascular disease (BF = 2.05; RR: 0.50; RD: -2.1%) and cancer mortality (BF = 2.26; RR: 0.35; RD: -3.3%) were more uncertain and less conclusive, as were those for an effect of starting to meet MVPA recommendations in the mid-fifties on mortality outcomes.