Strength Training & Incident Diabetes, CVD Rates

Older women who participate regularly in strength training can significantly reduce their rate of both type 2 diabetes mellitus (T2DM) and cardiovascular disease as compared with those who do not participate in strength training, according to a new study.

Federal guidelines on physical activity recommend muscle-strengthening activities at least twice a week in addition to at least 150 minutes per week of moderate-to-vigorous aerobic physical activity for health benefits. However, few studies have directly examined the longitudinal associations of weight lifting and strength training with incident T2DM and cardiovascular disease risk.

Researchers led by Eric J Shiroma, ScD, Med, of the National Institute of Aging, followed 35,754 healthy women, mean age 62.6 years, from the Women's Health Study. They had responded to a health questionnaire that included physical activity questions in 2000 that assessed health outcomes through annual health questionnaires through 2014.

Medical record reviews confirmed that 2,120 women had incident T2DM and 1,742 had cardiovascular disease. Cardiovascular disease was defined as confirmed cases of myocardial infarction, stroke, coronary artery bypass graft, angioplasty, or cardiovascular disease death.

The women who engaged in any strength training showed a 30% reduced rate of T2DM as compared to women who reported no strength training when controlling for time spent in other activities and other confounding factors. Women who engaged in strength training also had a 17% reduction in the risk for cardiovascular disease.

Those who participated in both strength training and aerobic activity had additional risk reductions for both T2DM and cardiovascular disease as compared with those who participated in aerobic activity only.

“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,” the researchers stated.

Several biological mechanisms support the concept of muscle-strengthening to reduce the risk of T2DM and cardiovascular disease, they noted. Resistance training has been shown to increase muscle mass, reduce body mass index (BMI), improve insulin sensitivity, and increase glucose transport. Randomized controlled trials of resistance exercise, either by itself or in combination with aerobic activity, have shown strength training can improve glycemic control among diabetics.

The new findings are similar to the results of studies that show weight lifting is associated with reduced rates of T2DM. A recent analysis of the Nurses' Health Study reported that women engaging in muscle-strengthening exercises had a reduced risk of T2DM ranging from 7% to 40%. In a cohort of male and female Japanese workers, participation in strength training was associated with a 34% decrease in risk of T2DM.

The researchers suggested that strength training, as recommended by the federal guidelines, may result in decreased rates of T2DM and cardiovascular disease. They noted that further research is needed to determine an optimum dose and intensity of muscle-strengthening activities for the reduction of T2DM and cardiovascular disease rates.

Reference: Shiroma EJ, et al. Strength training and the risk of type 2 diabetes and cardiovascular disease. Med Sci Sports Exerc. 2017 Jan;49(1):40-46.