The scientists used statistics from the Black Women's Health Study, which studied 45,000 black women from 1995 to 2005. The researchers found that those women who did at least five hours of brisk walking a week as exercise were one-third less at risk for developing type 2, or adult-onset, diabetes.
The vigorous walkers retained their health advantage when the researchers accounted for such possible influencing factors as age, income and diet. The research even showed that obese women's risk of developing type 2 diabetes was substantially lowered if they walked regularly.
"This is important," Palmer said, "because it suggests a way to reduce diabetes risk even among the women who are at highest risk of the disease. The finding that brisk walking for a few hours a week or longer reduces diabetes risk may be the most important finding of all. This is something almost all women can do in the course of their daily lives."
In addition, the research team discovered that women who watched television for five or more hours a day were 86 percent more at risk for developing diabetes than women who watched TV less than one hour a day.