Type 2 Diabetes Risk Drops With Weight Training Exercise

Aug. 6, 2012— -- Pumping iron can cut the risk of type 2 diabetes in men, a new study found.

The study of more than 32,000 men found those who lifted weights for at least two and a half hours a week were 34 percent less likely to develop type 2 diabetes, a chronic disease linked to complications including blindness, nerve damage, kidney failure and cardiovascular disease.

"Previous studies have shown that aerobic exercise is beneficial for the prevention of diabetes, but no epidemiological studies had looked at the impact of weight training," said Dr. Frank Hu, professor of nutrition and epidemiology at the Harvard School of Public Health and lead author of the study published today in the Archives of Internal Medicine. "This study demonstrates that weight training has benefits independent of aerobic exercise."

Aerobic exercise helps burns excess fat, a major risk factor for type 2 diabetes. But weight training helps boosts muscle mass, which is "very important for metabolism and insulin sensitivity," according to Hu.

Merging aerobic exercise and weight training was linked to a 59 percent reduction in diabetes risk, according to the study -- a link that held up even when the researchers controlled for unhealthy habits like smoking and drinking.

"The most important message from this study is that combining the two types of exercise confers the largest benefit," said Hu.

Because the study was done in men, it's unclear whether the findings extend to women.

More than 23 million Americans have type 2 diabetes, according to estimates from the U.S. Centers for Disease Control and Prevention -- a number expected to rise as American waistlines expand.

"These studies remind us that the fundamental cornerstone in the management of these pandemics is still lifestyle," Dr. Ruchi Mathur, an endocrinologist at the Cedars-Sinai Weight Loss Center in Los Angeles, said in an email. "We know that something as simple as walking can enhance insulin sensitivity."

Even people who already have diabetes can benefit from regular exercise, according to second study, published today in the same journal, that found "moderately active" diabetics were half as likely to die from cardiovascular complications as their physically inactive counterparts.

"The study reminds us that physical activity does not have to be aggressive to confer cardiovascular benefit in patients with diabetes," said Mathur. "In fact, simple leisure activities such as gardening and walking are beneficial."

ABC News' Dr. Shari Barnett contributed to this story.