Background: This is the first systematic review and meta-analysis to investigate the effect of resistance training (RT) on survival and other cardiovascular outcomes including ischemic heart disease events and stroke.
Methods: An experienced librarian searched databases up to September 25th, 2017, for randomized trials and cohort studies that evaluated the effect of RT on survival and cardiovascular events in the general population. The databases included Ovid MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus. Two investigators conducted the screening process independently and in duplicate. Cochrane tools were used to assess the risk of bias in clinical trials and observational studies. We calculated hazard ratios and 95% confidence intervals using RevMan and fixed and random effect models and had a subgroup analysis based on doses of RT and for the combination of RT and aerobic exercise (AE) vs no exercise.
Results: The search identified 1429 studies from which 10 (one randomized trial) met the inclusion criteria, including 338,254 participants with a mean follow up of 8.14 years. The meta-analysis showed that RT, in comparison with no exercises, is associated with 24% lower all-cause mortality and 48% lower mortality when combined with AE. Based on subgroup analysis, performing 1-2 sessions of RT/week is associated with lower all-cause mortality by 28% (HR 0.72, 95% CI 0.66-0.78) whereas > 5 sessions of RT/week has no association with all-cause mortality (HR 0.99, 95% CI 0.76-1.31). Further, RT alone or combined with AE is associated with lower CV mortality compared to no exercise (Figures). Finally, RT alone also showed a borderline association with lower all-cancer mortality. Heterogeneity was present for several comparisons, and subsequent analysis will explore sources of this variability. Using study design-specific Cochrane risk of bias tools, no major sources of bias were identified in the included studies. One cohort study looked at the effect of RT on coronary heart disease events and found 23% risk reduction in men, while no study specifically assessed the effect of RT on cerebrovascular outcomes.
Conclusion: RT is associated with lower all-cause, CV and all-cancer mortality. RT appears to have an additive effect when combined with AE.