Brisk steps can reduce diabetes risk.

Chalk up yet another reason to walk whenever possible. Quickly striding for an hour a day, even if it takes several installments, can cut nearly in half a woman's risk of developing diabetes, according to a large nationwide study.

Among 70,102 nurses followed for 8 years, the fifth that exercised most was only 54 percent as likely to develop adult onset, or type 2, diabetes as was the fifth that exercised the least. Overall, women who were more physically active had a lower risk of diabetes, scientists report in the Oct. 20 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION.

However, many women did not engage in what the researchers deemed vigorous activities, such as running, jogging, biking, or aerobics. Among women whose only activity was walking, the fifth who walked longest and fastest were only 58 percent as likely to develop diabetes as those who walked least.

Some benefit arises because women who exercise more tend to weigh less, which reduces their chance of developing diabetes, says lead researcher Frank B. Hu of the Harvard School of Public Health in Boston. Even after accounting for weight, however, the advantages of both vigorous exercise and walking remained.

Several other studies have suggested that the more people exercise the less likely they are to have diabetes, but this study is one of the first to follow large numbers of people, Hu says. It's also the first to look at the benefits of moderate exercise, such as walking.

His findings indicate that "there are simple ways to accumulate enough exercise to reduce the risk of developing diabetes--walking to the bus stop in the morning, walking several flights of stairs, or doing housework," Hu says. "Importantly, practical physical activity like this can reduce the risk of type 2 diabetes among both obese and nonobese women."

Type 2 diabetes, a disorder resulting from the body's inability to control blood sugar concentrations, affects an estimated 15 million people in the United States and is the leading cause of blindness and kidney disease in adults. People with diabetes are also likely to suffer nerve damage, heart disease, and stroke.

Philip E. Cryer of Washington University School of Medicine in St. Louis cautions that exercise might simply delay the onset of diabetes in women. However, "walking is a practical activity that is within everyone's ability. Staving off complications [of diabetes] for even a few years could have a major impact," he says.