Sept. 25 (HealthDay News) -- Regular exercise may help protect men from prostate cancer, says a new study.

U.S. researchers looked at 190 men who had a prostate biopsy and found that those who were moderately active -- anything equivalent to walking at a moderate pace for several hours a week -- were significantly less likely to be diagnosed with prostate cancer.

The study also found that exercise was associated with less aggressive disease in men who did develop prostate cancer.

"As the amount of exercise increased, the risk of cancer decreased," lead author Dr. Jodi Antonelli, a urology resident at Duke University Medical Center, said in a news release.

The results, published Sept. 22 online in the Journal of Urology, contribute to the ongoing debate about how exercise affects prostate cancer risk, said study senior author Dr. Stephen Freedland, a urologist at Duke and the Durham Veterans Affairs Hospital.

"There have been dozens of studies about the value of exercise in lowering risk of prostate cancer, and some of them quite large, but the bottom line is that they've left us with mixed signals," Freedland said in the news release.

The majority (58 percent) of the men in this study were sedentary, which means they exercised less than the equivalent of one hour per week of easy walking.

SOURCE: Duke Medicine, news release, Sept. 22, 2009