Dose-response association of aerobic and muscle-strengthening physical activity with mortality: a national cohort study of 416 420 US adults

Objectives To investigate the dose-response association of aerobic physical activity (PA) and muscle-strengthening exercise (MSE) with all-cause mortality. Methods National Health Interview Survey data (1997-2014) were linked to the National Death Index through 2015, which produced a cohort of 416 420 US adults. Cox proportional-hazard models were used to estimate HRs and 95% CIs for the associations of moderate aerobic PA (MPA), vigorous aerobic PA (VPA) and MSE with mortality risk. Models controlled for age, sex, race-ethnicity, income, education, marital status, survey year, smoking status, body mass index and chronic conditions. Results Relative to those who engaged in no aerobic PA, substantial mortality risk reduction was associated with 1 hour/week of aerobic PA (HR: 0.85, 95% CI: 0.83 to 0.86) and levelled off at 3 hours/week of aerobic PA (0.73, 0.71 to 0.75). Similar results were observed for men and women and for individuals younger and older than 60 years. MSE conferred additional mortality risk reduction at 1 time/week (0.89, 0.81 to 0.97) and appeared no longer beneficial at 7 times/week (0.99, 0.94 to 1.04). Conclusion The minimum effective dose of aerobic PA for significant mortality risk reduction was 1 hour/week of MPA or VPA, with additional mortality risk reduction observed up to 3 hours/week. For older adults, only small decreases in mortality risk were observed beyond this duration. Completing MSE in combination with aerobic PA conferred additional mortality risk reduction, with a minimum effective dose of 1-2 times/week.

Automated summary

This study investigated the dose-response association between aerobic physical activity (PA) and muscle-strengthening exercise (MSE) with all-cause mortality. The results showed that engaging in at least 1 hour of aerobic PA per week significantly reduced the risk of mortality, with additional risk reduction observed up to 3 hours per week. Completing MSE once a week also conferred additional mortality risk reduction, but the benefits plateaued after exercising 7 times per week. For older adults, the decreases in mortality risk beyond the threshold were smaller.