Weight Training, Aerobic Exercise Cut Type 2 Diabetes Risk

Troy Brown

August 06, 2012

August 6, 2012 — Weight training and aerobic exercise are each associated with a significantly lower risk for type 2 diabetes mellitus (T2DM) in men, and the benefits are even greater when the 2 activities are combined, according to a study published online August 6 in the Archives of Internal Medicine.

Anders Grøntved, MPH, MSc, a doctoral student at the Institute of Sport Science and Clinical Biomechanics, Exercise Epidemiology Research Unit, and Centre of Research in Childhood Health at the University of Southern Denmark in Odense and a visiting researcher in the Department of Nutrition at the Harvard School of Public Health in Boston, Massachusetts, and colleagues wanted to study the association between weight training and risk for T2DM.

"[W]hereas the evidence that regular aerobic exercise can prevent T2DM is compelling, to our knowledge, no studies have examined the role of weight training in the primary prevention of T2DM," the authors write.

The researchers analyzed data from the Health Professionals Follow-up Study, an ongoing prospective cohort study of 51,529 male health professionals who were aged 40 to 75 years in 1986. Cohort participants are sent a questionnaire biennially about health issues including dietary intake, exercise, disease, height, and weight.

From 1990 forward, the questionnaires asked men to describe their weekly amount of all physical activity and television viewing. The researchers analyzed data for patients who were diagnosed with T2DM between the return of the 1990 questionnaire and January 31, 2008.

For the current analysis, men who reported a history of diabetes, myocardial infarction, angina, coronary artery bypass graft, other heart conditions, stroke, pulmonary embolism, or cancer on the baseline questionnaire in 1986, in 1988, or in 1990 were excluded. This left a study population of 32,002 participants.

Participants were placed into 1 of 4 categories, based on the total number of minutes they spent on aerobic exercise of at least moderate intensity: 0, 1 to 59, 60 to 149, and at least 150 minutes per week. Men were placed in the same categories for weight training. The team also constructed a variable to measure unstructured physical activity of at least moderate intensity, such as heavy outdoor work and stair climbing.

During 508,332 person-years of follow-up (18 years), 2278 new cases of T2DM were documented.

Compared with men who reported no weight training at baseline, men who performed at least 150 minutes/week of weight training did more aerobic exercise, had a healthier dietary intake (except for glycemic load), drank less alcohol, were less likely to smoke, and viewed less television.

Men who performed weight training from 1 to 59 minutes/week had a relative risk (RR) for T2DM of 0.88 compared with nonexercisers in a multivariable-adjusted analysis. For men who performed from 60 to 149 minutes of weight training/week, the relative risk was 0.75, and for those in the highest category of weight training (150 minutes or more/week), it was 0.66 (P < .001 for trend). The multivariable model was adjusted for age, smoking, alcohol consumption, coffee intake, race, family history, dietary factors, and aerobic activity.

Even smaller amounts of weight training were helpful, however. Men who reported any amount of weight training at all had a 48% (95% confidence interval [CI], 1% - 72%) lower risk than men who did no weight training.

For men who reported 1 to 59, 60 to 149, and at least 150 minutes per week of aerobic exercise, the RRs of T2DM were .93, 0.69, and 0.48, respectively (P < .001 for trend) compared with men who did not do aerobic exercise.

The researchers found a dose-response relationship for weight training: the risk for T2DM decreased by 13% (95% CI, 6% - 19%; P < .001) for each 60 minutes of weight training performed per week. The strongest association was found at the lower level of aerobic exercise (P < .001 for the nonlinear response).

Men who performed at least 150 minutes of aerobic exercise per week and at least 150 minutes of weight training per week obtained the most benefit (RR, 0.41; 95% CI, 0.27 - 0.61; P = .26 for multiplicative interaction).

"These results support that weight training serves as an important alternative for individuals who have difficulty adhering to aerobic exercise, but the combination of weight training with aerobic exercise conferred an even greater benefit," the authors write.

Because the study participants were mostly white men, the results may not be generalizable to women or other ethnic or racial groups.

The study is supported by grants from the National Institutes of Health. The authors have disclosed no relevant financial relationships.

Arch Intern Med. Published online August 6, 2012. Full text


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