Physical activity. An effective weapon against cancer.

 By: Aude Rambaud – Le Figaro Santé

Physical activity is beneficial before, during, and after cancer. When practiced in sufficient amounts, it significantly reduces the risk of developing the disease. It is even one of the modifiable preventative factors, along with abstinence from alcohol and tobacco, and a good diet. Numerous studies prove its protective effect against various types of cancer, notably breast and colon cancer, which are among the most frequent. Endometrial, lung, rectal, prostate, ovarian, thyroid, and pancreatic cancers also have a direct relationship with lack of physical activity. The evidence supporting the relationship between cancer and lack of physical activity is numerous and important.

The protective effect of physical activity can now even be evaluated in concrete numbers thanks to these studies: the risk of developing colon cancer decreases by 17% in cases of regular physical activity compared to a sedentary state, and the risk of breast cancer decreases by about 20%. “These figures may seem moderate, but when you consider the incidence of these cancers, the benefit is very significant on a population scale,” explains Raphaëlle Ancellin, from the prevention department of the National Cancer Institute in France. “Furthermore, there is a 'dosage effect,' meaning that the more intense and regular the physical activity, the more significant the protective effect,” clarifies Ancellin. Therefore, for every thirty minutes of supplemental physical activity per day, the risk of colon cancer decreases by about 12%.

The benefits of physical activity are, moreover, verifiable at all ages. “A study conducted with three age groups (individuals under 25, between 25 and 50, and over 50) showed that physical activity significantly reduces the risk of breast cancer. This means that there is no age limit for a person to start moving; it’s never too late,” insists Raphaëlle Ancellin.

All physical exertion is beneficial, even the briefest and lowest intensity. These protective properties are explained through several mechanisms: better control of body weight, the increase of which is associated with various cancers (esophagus, endometrium, kidneys, colon and rectum, pancreas, and also breast cancer after menopause), as well as a reduction in the rate of certain hormones and growth factors (insulin, IDF-1, etc.), which favor cell proliferation.

Reduce oxidative stress

Other mechanisms, on the other hand, are even more specific. For colon cancer, the acceleration of intestinal transit caused by physical exertion reduces the exposure time of the digestive mucosa to foodborne carcinogens. For breast cancer, exercise decreases the rate of circulating estrogens and improves immunity. For lung cancer, increased respiratory function reduces the concentration of carcinogenic agents in that organ, as well as the oxidative stress caused by cigarettes and tobacco in general.

"The important thing, even if these recommendations are difficult to implement, is that the person moves a lot throughout their journey," says Professor Daniel Rivière, head of sports medicine at Larrey Hospital in Toulouse.

The recommendations for physical activity to prevent cancer are identical to those recommended for other diseases such as obesity or cardiovascular pathologies. Namely: at least thirty minutes of moderate-intensity physical activity at least five days a week for adults, and at least one hour a day for children. "But it's good to remember that these are global averages, and that any and all physical exertion is beneficial, even shorter and lower-intensity activities," reminds Raphaëlle Ancellin.

“The important thing, if these recommendations are difficult to follow, is that the person moves throughout their day,” advises Professor Daniel Rivière. Walking while talking on the phone, going up and down stairs, walking or cycling to work are also effective measures, perhaps even better than forcing oneself to get up from the armchair to do some physical activity for half an hour.

Finally, even when a person has cancer, physical activity is recommended, taking into account the patient's capabilities. Many studies have conclusively demonstrated that adapted activity of low to moderate intensity during chemotherapy or radiological treatment improves quality of life and brings many benefits against fatigue, anxiety, depression, sleep, body image, and general well-being.

Above all, physical activity is associated with a reduction in the risk of death of about 40% on average – for breast and colon cancer – provided it is practiced regularly after diagnosis. This figure varies considerably depending on the nature and severity of the cancer, but it should encourage patients not to be discouraged by physical exertion.