Purpose: This study aimed to examine the association of strength training with incident type 2 diabetes and cardiovascular disease risk.
Methods: We followed 35,754 healthy women (mean age = 62.6 yr, range = 47.0-97.8) from the Women's Health Study, who responded to a health questionnaire that included physical activity questions in 2000, assessing health outcomes through annual health questionnaire through 2014 (mean ± SD follow-up = 10.7 ± 3.7 yr). Incident type 2 diabetes (N cases = 2120) and cardiovascular disease (N cases = 1742) were confirmed on medical record review. Cases of cardiovascular disease were defined as confirmed cases of myocardial infarction, stroke, coronary artery bypass graft, angioplasty, or cardiovascular disease death.
Results: Compared with women who reported no strength training, women engaging in any strength training experienced a reduced rate of type 2 diabetes of 30% (hazard ratio = 0.70, 95% confidence interval = 0.61-0.80) when controlling for time spent in other activities and other confounders. A risk reduction of 17% was observed for cardiovascular disease among women engaging in strength training (hazard ratio = 0.83, 95% confidence interval = 0.72, 0.96). Participation in both strength training and aerobic activity was associated with additional risk reductions for both type 2 diabetes and cardiovascular disease compared with participation in aerobic activity only.
Conclusions: These data support the inclusion of muscle-strengthening exercises in physical activity regimens for reduced risk of type 2 diabetes and cardiovascular disease, independent of aerobic exercise. Further research is needed to determine the optimum dose and intensity of muscle-strengthening exercises.