A new study from the University of Texas MD Anderson Cancer Center found a potential mechanism through which intense exercise can help to prevent cancer (Clin Cancer Research, Sept 27, 2023;29(20)). Lynch Syndrome is a hereditary condition that affects more than a million North Americans, and puts these men and women at an 80 percent chance of developing colon cancer at a very young age, and the women at a 60 percent chance of developing endometrial cancer. Twenty-one people with Lynch Syndrome were split into two groups:
• 45 minutes of intense cycling three days a week for 12 months
• no exercise

The exercisers had a marked rise in natural killer cells and CD8+ T cells in both their blood and their colon. These immune cells specifically attack and try to kill invading germs and cancer cells. Furthermore, their inflammatory markers such as prostaglandin E2 (PGE2) dropped significantly to show that the reaction that tries to kill cancer cells had dropped, suggesting that the inflammatory reaction trying to limit the spread of cancer cells had slowed down. The authors state that this is the first study to demonstrate a link between exercise and changes in immune biomarkers for cancer.

How Exercise Might Help to Restrict Cancer Growth
All normal cells are programmed to live only for a limited time and then die. For example, skin cells live only 28 days and then die. This is healthful and is called apoptosis. Cancer means that the cells try to live forever, and they can become so numerous that they can invade and destroy normal tissues. For example, a woman does not die from breast cancer as long as the cancer remains in the breast. However, if the breast cancer cells invade the liver or the brain, they destroy the normal function of these essential organs and the person dies from liver or brain damage.

Everybody makes cancer cells every day, but your immune system recognizes that cancer cells are different from normal cells and works to kill these cancer cells in the same way it works to kill invading germs. Many studies show that exercise helps your immunity to recognize and kill cancer cells:

• A review of 45 reports of epidemiologic studies with several million study participants found that compared to those with the lowest level of physical activity, those with the highest activity levels had significantly lower rates of bladder, breast, colon, endometrial, esophageal adenocarcinoma, renal, and gastric cancers (Med Sci Sports Exerc. Jun, 2019;51(6):1252–1261).

• Another study of nearly 23,000 non-exercisers found that those who performed vigorous intermittent lifestyle physical activity for at least 4.5 minutes a day had a 32 percent reduced cancer risk (JAMA Oncol, 2023;9(9):1255-1259).

• A study of 25,241 people who didn’t exercise but moved about vigorously at least three times a day for one to two minutes each had a 38 percent to 40 percent lowered risk of all-cause and cancer death risk, as well as a nearly 50 percent lowered risk of dying from cardiovascular disease (Nature Medicine, 2022;28:2521-2529). This suggests that you may be able to help prevent cancer by climbing stairs, power walking, carrying heavy grocery bags, mowing the lawn, carrying out your garbage and so forth.

My Recommendations
Having a regular exercise program helps to prevent certain cancers. If you don’t have the time or desire to be in an exercise program, at least you can move about vigorously when you walk, climb stairs or perform your daily tasks. You should also follow an anti-inflammatory diet, avoid smoke and alcohol, and limit your exposure to toxic chemicals.