ScienceDaily (Dec. 8, 2009) — As little as 15 minutes of exercise a day can reduce overall mortality rates in patients with prostate cancer, according to findings presented at the American Association for Cancer Research Frontiers in Cancer Prevention Research Conference, held here, Dec. 6-9, 2009.
"We saw benefits at very attainable levels of activity," said Stacey A. Kenfield, Sc.D., epidemiology research associate at the Harvard School of Public Health and lead author of the study. "The results suggest that men with prostate cancer should do some physical activity for their overall health."
Researchers assessed physical activity levels for 2,686 patients enrolled in the Health Professionals Follow-up Study, both before and after diagnosis (men with metastases at diagnosis were excluded).
Men who engaged in three or more hours of Metabolic Equivalent Tasks (MET) a week -- equivalent to jogging, biking, swimming or playing tennis for about a half-hour per week -- had a 35 percent lower risk of overall mortality.
Specific to walking, the researchers found that men who walked four or more hours a week had a 23 percent lower risk of all-cause mortality compared to men who walked less than 20 minutes per week. Men who walked 90 or more minutes at a normal to brisk pace had a 51 percent lower risk of death from any cause than men who walked less than 90 minutes at an easy walking pace.
Walking didn't show any effect on prostate cancer specific mortality, but more strenuous exercising did. Men who engaged in five or more hours of vigorous physical activity a week were at a decreased risk of dying from their prostate cancer.
"This is the first large population study to examine exercise in relation to mortality in prostate cancer survivors," said Kenfield. Previous studies focused on how exercise affects risk of developing prostate cancer. Kenfield said that researchers aren't sure of the exact molecular effects exercise has on prostate cancer, but exercise is known to influence a number of hormones hypothesized to stimulate prostate cancer, boost immune function and reduce inflammation.
"How these factors may work together to affect prostate cancer biologically is still being studied," she said. "For now, our data indicate that for prostate cancer survivors, a moderate amount of regular exercise may improve overall survival, while five or more hours per week of vigorous exercise may decrease the death rate due to prostate cancer specifically."
