HOW DOES EXERCISE PREVENT CANCER?

“There are several chronic diseases more destructive to life than than cancer, none is more feared.” -Charles Mayo  (1865–1939 )

It is well known fact that the necessity of bodily exercise is in our genes. Our ancient ancestors were hunter-gatherers. Exercise boosts our immune system, increases key immune cells ( T-lymphocytes) in the blood, thereby helping to prevent all kind of cancers, especially colon cancer. The World Health Organization states that 1/3 of all cancers are preventable.

What can we do to prevent our risk of cancers? Scientific epidemiologic studies have shown that taking the following measures will significantly decrease our risk of developing a cancer:  

Regular exercises, controlling our weight, changing our eating habits and diet (as mentioned in previous articles), avoiding sunburns, getting vaccinated against HBV (hepatitis B virus) and HPV, cutting our alcohol consumption, stop smoking, having regular checkups and having colonoscopy screenings as well as making sure that we do not have H. pylori infection in our stomach to prevent stomach cancers.

Colon cancer is the third most common cancer in the world. Every year in the USA, more than 50,000 people die because of colon cancer and more than 100,000 new cases are diagnosed. There is an interesting relationship between colon cancer rates and exercise. Exercise seems to prevent colon cancer.

How does exercise prevent colon cancer? We know that exercise speed up the movement of waste throughout the intestine, thereby reducing the contact time of waste which might contain some cancer producing (carcinogen) waste products that damage colonic mucosa. However this is not very convincing explanation.

Is it possible that exercise produces some chemicals in the blood that inhibit the development of colon cancer?

An interesting scientific study from Australia that recently was published in the Journal of Physiology, tries to shed some light on this curious phenomenon. Scientists, after growing colon cancer culture cells in petri dishes, recruited 20 men who survived colon cancer and have them exercise strenuously and many times, in short intervals, daily for a month. A 10 men control group exercised only once a day. 

After a month, they drew blood from the patients in both groups, immediately after exercise and after two hours rest; and added these blood samples in to the petri dishes with colon cancer cell cultures. 72 hours later when they examined petri dishes, they found out that there was no growth but a significant reduction in cancer cells only in the petri dishes of the men who had immediately exercised.  No change for the blood taken 2 hours after rest. When they examined the blood chemistry of the samples taken immediately after exercise, they found that there were significant amount of acute phase inflammatory chemical molecules (CRP) in the blood, but not in the blood taken after two hours rest. They concluded that exercise induces transitory increase in inflammatory molecules in the blood and that these molecules prevent the growth of cancer cells in cultures.

So, it appears that this study also supports the idea that regular exercise should be a part of cancer prevention AND cancer treatment programs.