A new study suggests that men who exercise at a moderate rate may have a lower risk of prostate cancer than sedentary men.

Researchers found in a group of 190 men who underwent biopsies to detect possible prostate cancer that those who had been exercising regularly had a lower chance of being diagnosed with the disease.

Men who exercised moderately which would be equal to three or more hours of brisk walking every week were two-thirds less likely than their sedentary counterparts to have prostate cancer.

On the other hand, those who did have the disease and included only one hour of walking per week were less likely to have an aggressive or fast-growing cancer.

Dr. Jodi A. Antonelli and colleagues at Duke University Medical Center in Durham, North Carolina said, "It is impossible to state that exercise alone was responsible for the benefits we observed because participants who exercised might also have engaged in other behaviors linked to better health, like adhering to good diet”.

Other reasons that support this finding are that exercise tends to lower testosterone and other hormones that help feed prostate tumor growth.

Exercise could also boost the immune system by damaging abnormal cells before they can develop to form tumors.

The researchers conclude that the findings definitely suggest that exercise protects against prostate cancer but they could not prove it beyond all doubt.