Weight training found to lessen type 2 diabetes risk in men

Physicians should encourage male patients to add moderate weight lifting to their fitness regimens to help prevent the development of type 2 diabetes, says the author of a recent Harvard School of Public Health study.

Men who do weight training for 30 minutes, five days a week, might be able to reduce their risk of developing the chronic disease by up to 34%, said the study, published online Aug. 6 in Archives of Internal Medicine.

But even modest lifting, such as 20 minutes, two or three times a week, can decrease a man’s diabetes risk, said senior study author Frank B. Hu, MD, PhD.

“It’s pretty well-established that increasing aerobic exercise is beneficial to diabetes prevention,” said Dr. Hu, a professor of nutrition and epidemiology in the Dept. of Nutrition and Epidemiology at Harvard School of Public Health in Boston. “But no epidemiological studies have looked at weight training and diabetes risk. This study provides some very clear evidence that weight training is beneficial for diabetes prevention, independent of aerobic exercise.”

Researchers are conducting a similar analysis of women to see whether weight lifting also helps reduce their risk of developing the disease.

Diabetes has been rising steadily in the United States since 1980, when 5.6 million people were diagnosed with the condition, according to the Centers for Disease Control and Prevention. The figure more than quadrupled by 2010, swelling to about 25.8 million Americans. An estimated 7 million of those individuals are not aware they have the disease.

Researchers examined data on 32,002 men 40 and older who were observed as part of the Health Professionals Follow-up Study between 1990 and 2008. Men were excluded if they had cancer, diabetes, myocardial infarction or stroke, among other conditions.

Weekly time spent on weight training and aerobic exercise, including brisk walking, jogging, swimming and tennis, was obtained from questionnaires at the start of the study and then every two years during follow-up.

The study found 2,278 new cases of type 2 diabetes during that period. Weight training was associated with a significantly lower risk of contracting the disease.

Men who engaged in the activity for up to 59 minutes a week had a 12% reduced risk of developing diabetes compared with those who didn’t lift weights. Weight training for an hour to 149 minutes a week was associated with a 25% lower risk (link).

The greatest risk reduction was seen among participants who combined weight training and aerobic exercise. Men who did more than 150 minutes of aerobics and at least 150 minutes of lifting a week had a 59% lowered risk of developing diabetes. The two exercises don’t have to be performed during the same session, Dr. Hu said.

The association of weight training with lowered diabetes risk weakened in men 65 and older and among those with a family history of the disease.

“The take-home message is that both weight training and aerobics are beneficial,” Dr. Hu said. “The combination of those two exercises can confer even greater benefits.”