May 11, 2005 - A study in the recent in the Archives of Internal Medicine (Giovannucci, E. 165:1005-10, May 9, 2005) of more than 47,000 men who participated in the Health Professionals Follow-Up Study found that men over the age of 65 who exercised vigorously 3 or more hours a week had a 70% reduction in prostate cancer. The benefit was not apparent in younger men.
Why should this be? We don't know, but one possible explanation is the effect of exercise on the immune system. Prostate cancer occurs at the time in men's lives when the immune system is weakened.
Our research has shown that in animals "healthy, voluntary" exercise is associated with reduced growth of prostate cancer (Bryner R: JEP Online, 1998 Volume: 1 - Issue: 2). Stimulation of the immune system with BCG can reduce the growth of prostate cancer (Lamm, 1992) and the combination of BCG and exercise further reduces tumor growth (Bryner R: JEP Online, 7: 3, June 2004). Moderate exercise training has been shown to significantly increase serum immunoglobins, monocytes, and natural killer (NK) cell number and activity -- this is immune stimulation that can not only reduce the effects of common infections such as colds, but also have a beneficial effect in reducing or eliminating some cancers.
Created: 5/11/2005