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It already lowers your blood pressure, cholesterol, and risk of diabetes, stroke and heart disease, as well as boosting your sexual desirability and subsequent performance. Now it turns out that exercise may also keep cancer at bay, even if you're a smoker.

Researchers followed 25,892 men, ages 30 to 87, for an average of more than 10 years. During that period, there were 335 cancer deaths. The results were adjusted for age, examination year, smoking habits, alcohol intake, body mass index and diabetes.

"Moderate and high levels of cardio-respiratory fitness were associated with lower risk of smoking-related and nonsmoking-related cancer mortality when compared with low fitness in men," report lead authors Chong Do Lee of West Texas A&M University in Canyon, and Steven Blair of the Cooper Institute in Dallas. Thus, "fitness may provide protection against cancer mortality in men." Researchers at the University of Minnesota at Minneapolis also participated in the study, which was published in the journal Medicine & Science in Sports & Exercise.

The fittest subjects, considered "recreationally competitive," had a 55 percent reduction in overall cancer death. Moderate fitness, defined as the equivalent of running 20 to 40 minutes three to five days a week, was rewarded with a 38 percent risk drop.

The benefits widened to 66 percent and 43 percent, respectively, when assessing smoking-related cancers. About 10 percent of the fittest group smoked, compared to 20 percent of the moderately fit group and 33 percent of the sedentary group. If the sedentary subjects who smoked had become fit, the researchers calculated, they would have reduced their mortality risk by 13 percent.

Several theories were put forth to explain the benefits, the first being that cardiovascular exercise may help clear the lungs of cancer-causing chemicals. Fitness regimens could also improve the body's defenses against cancerous tumors, and/or help the body withstand the debilitating effects of cancer treatments. In addition, fit men are generally more health-conscious than sedentary men, and thus may seek medical treatment at earlier stages.

The study was less encouraging for light exercisers. Taking a walk may help your heart, but it appears you need to break a sweat to reduce your cancer risk.

This confirms an earlier study at the Royal Free and University College Medical School in London. After tracking 7,588 men for 18 years, investigators found that cancer protection only seemed to occur in those who pursued moderately vigorous or vigorous exercise. "Sporting activity was essential to achieve significant benefit," concluded the report, published last year in the British Journal of Cancer.

# posted by Medical Information : 1:39 AM