DURHAM, N.C., Dec. 18 (UPI) -- Even a modest amount of brisk walking weekly can cut the risk of metabolic syndrome, which is linked to heart disease and diabetes, a U.S. study found.

Researchers from Duke University Medical Center in Durham, N.C., said an estimated one-quarter of all U.S. adults have metabolic syndrome, a cluster of risk factors including: large waist circumference, high blood pressure, high levels of triglycerides, low amounts of HDL, or "good" cholesterol and high blood sugar. To be diagnosed with metabolic syndrome, patients must have at least three of the five risk factors.

Lead author Johanna Johnson said a person can lower the risk of metabolic syndrome by walking just 30 minutes a day, six days per week. "That's about 11 miles per week," Johnson said in a statement. "Our study shows that you'll benefit even if you don't make any dietary changes."

The results come from a multi-year, federally funded study that examined the effects of varying amounts and intensity of exercise on 171 middle-aged, overweight men and women.

The study, published in the journal American Journal of Cardiology, found that before exercising regularly, 41 percent of the participants met the criteria for metabolic syndrome, but at the end of the eight-month exercise program, 27 percent did.