Background: The benefits of aerobic exercise are well-studied; there is no consensus on the association between resistance training and major adverse cardiovascular outcomes. This systematic review and meta-analysis aimed to address this issue.
Design and methods: We searched for randomized trials and cohort studies that evaluated the association between resistance training and mortality and cardiovascular events. Two investigators screened the identified abstracts and full-texts independently and in duplicate. Cochrane tools were used to assess the risk of bias. We calculated hazard ratios and 95% confidence intervals using random effect models.
Results: From the 1430 studies identified, 11 (one randomized trial and 10 cohort studies) met the inclusion criteria, totaling 370,256 participants with mean follow-up of 8.85 years. The meta-analysis showed that, compared with no exercise, resistance training was associated with 21% (hazard ratio (95% confidence interval (CI)), 0.79 (0.69-0.91)) and 40% (hazard ratio (95% CI), 0.60 (0.49-0.72)) lower all-cause mortality alone and when combined with aerobic exercise, respectively. Furthermore, resistance training had a borderline association with lower cardiovascular mortality (hazard ratio (95% CI), 0.83 (0.67-1.03)). In addition, resistance training showed no significant association with cancer mortality. Risk of bias was low to intermediate in the included studies. One cohort study looked at the effect of resistance training on coronary heart disease events in men and found a 23% risk reduction (risk ratio, 0.77, CI: 0.61-0.98).
Conclusion: Resistance training is associated with lower mortality and appears to have an additive effect when combined with aerobic exercise. There are insufficient data to determine the potential beneficial effect of resistance training on non-fatal events or the effect of substituting aerobic exercise with resistance training.
Keywords: Resistance training; cardiovascular outcome; meta-analysis; mortality; strength training; systematic review.