Weight training and risk of all-cause, cardiovascular disease and cancer mortality among older adults.

BACKGROUND: While previous studies indicate muscle-strengthening exercises may reduce mortality risk, further research is needed to increase certainty of the evidence. We investigated overall and dose-response associations between weight training and the risks of all-cause, cardiovascular disease (CVD) and cancer mortality in a large cohort of older adults with long follow-up time and a large number of deaths. We also investigated the joint associations of weight training and aerobic exercise with mortality risk. METHODS: Weight training was assessed via self-report in 2004-05 in the National Institutes of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study (USA; n = 216 339), with follow-up to 2019. Cox regression estimated the hazard ratios (HR) and 95% confidence intervals (CI) for the associations between weight training and mortality, after adjusting for confounders including aerobic exercise. RESULTS: Around 25% of participants [mean age = 69.9 years (standard deviation = 5.4), 58% men] reported engaging in weight training over the past year, and there were 79 107 (37%) deaths. Engaging in any weight training (vs none) was associated with lower risks of all-cause (HR = 0.94; 95% CI = 0.93-0.96), CVD (HR = 0.92; 95% CI = 0.90-0.95) and cancer mortality (HR = 0.95; 95% CI = 0.92-0.98). More time spent in weight training was associated with only marginally greater risk reductions. Larger risk reductions were observed among women than men. Performing both aerobic exercise and weight training conferred the greatest mortality risk reduction; weight training was not associated with mortality risk among participants who did no aerobic exercise. CONCLUSION: Performing any amount of weight training lowered mortality risk.

Resistance Training and Mortality Risk: A Systematic Review and Meta-Analysis.

INTRODUCTION: This study aimed to systematically review and meta-analyze the relationship between resistance training and all-cause, cardiovascular disease, and cancer mortality. METHODS: Systematic review and meta-analysis following PRISMA guidelines (International Prospective Register of Systematic Reviews Registration Number CRD42019136654) was conducted. MEDLINE (OVID), Embase, Emcare, SPORTDiscus, The Cochrane Library, and SCOPUS were searched from inception to June 6, 2021. Included studies reported resistance training as the exposure and all-cause mortality, cardiovascular disease‒specific mortality, and/or cancer-specific mortality as outcome/s. Only studies conducted among nonclinical adult populations (aged ≥18 years) and written in English were included. RESULTS: A total of 10 studies were included in the meta-analyses. Compared with undertaking no resistance training, undertaking any amount of resistance training reduced the risk of all-cause mortality by 15% (RR of 6 studies=0.85; 95% CI=0.77, 0.93), cardiovascular disease mortality by 19% (RR of 4 studies=0.81; 95% CI=0.66, 1.00), and cancer mortality by 14% (RR of 5 studies=0.86; 95% CI=0.78, 0.95). A dose-response meta-analysis of 4 studies suggested a nonlinear relationship between resistance training and the risk of all-cause mortality. A maximum risk reduction of 27% was observed at around 60 minutes per week of resistance training (RR=0.74; 95% CI=0.64, 0.86). Mortality risk reductions diminished at higher volumes. DISCUSSION: This systematic review and meta-analysis provides the strongest evidence to date that resistance training is associated with reduced risk of all-cause, cardiovascular disease, and cancer-specific mortality. More research is needed to determine whether any potential mortality benefits gained from resistance training diminish at higher volumes.