For years now, researchers have suspected that exercise lowered the risk of prostate cancer, but several studies turned up conflicting results. Now, from Harvard T.H. Chan School of Public Health, a large scale study suggests that exercise can lower the risk of aggressive prostate cancer. A Harvard news release reports that scientists analyzed data from 49,160 men between the ages of 40 and 75 who enrolled in The Health Professionals Follow-up Study in 1986 and were followed to 2012. The men responded to biennial questionnaires that included questions about diet, health, and physical activity. Among the participants, 6,411 developed prostate cancer and 888 developed a lethal form of the disease. The researchers found that men who engaged most frequently in vigorous activity had a 30 percent lower risk of developing advanced prostate cancer and 25 percent lower risk of developing lethal prostate cancer when compared with men who exercised the least. On average, men in the highest category of vigorous activity engaged in an equivalent of 25 minutes of running daily. What exactly is vigorous activity? For this study, it included bicycling, swimming, heavy outdoor work, and playing sports such as tennis or racquetball.