There is a potential ‘dose-dependent’ benefit of exercise, especially against breast cancer in post-menopausal women and colon cancer, that is, the more exercise , the greater the benefit. In general, elite athletes or people who have practiced more exercise have a 40% lower risk of cancer mortality than the rest of the population. However, this approach may lead to a review of whether this association is really true. Thus, physically active people can follow other healthy behaviors such as a balanced diet, less alcohol and tobacco consumption or better access to medical services than the rest. In such a way that, following the aforementioned patterns, it could be thought that physical exercise itself may not have such antitumor effects …
However, scientific evidence shows that physical exercise has potential antitumor effects through different biological processes. First, numerous indirect mechanisms mediate the benefits of physical exercise against cancer. Physical activity reduces the expression of oncogenes (genes with great mutational capacity and therefore tumorigenic); reduces the levels of circulating sex hormones; induces antioxidant defense in many tissues, thus preventing free radicals from damaging DNA, causing it to mutate; and, in addition, it fights numerous metabolic disorders, such as obesity, chronic inflammation and insulin resistance, all of them factors associated with some types of cancer. On the other hand, it has been proven that physical exercise mediates various mechanisms related to autophagy , a system of destruction and recycling of damaged biological material that has recently given much to talk about thanks to the Nobel Prize in Medicine, Yoshinori Ohsumi.
Physical exercise has direct effects against cancer
It should be noted that physical exercise also induces numerous direct effects against cancer. During an exercise session, muscle fibers contract and release proteins – known as ‘myokines’ – into the blood, from where they travel to many tissues, in which they perform different functions. Some of these myokines increase insulin sensitivity, increase the metabolism of our fat tissue, control the growth of our muscles and even act on the brain by mediating neuronal plasticity . Other myokines mediate anticancer effects by preventing the proliferation of damaged cells and promoting them to return to their natural state of ‘programmed death’ (a phenomenon known as ‘apoptosis’), instead of becoming immortal.
The myokine oncostatin M has been shown to promote apoptosis in breast cancer tumor cells, thus preventing the growth of this type of cancer. Another protein that has been shown to be released into the blood from contracting skeletal muscles is SPARC, which suppresses the growth of colon cancer. On the other hand, it has been shown in different animal models that the multifaceted interleukin-6 promotes antitumor effects in melanoma and liver and lung cancer. In addition, its action combined with the hormone adrenaline, which our adrenal glands release during exercise, increases the mobilization of NK lymphocytes (natural killer, true ‘guardians’ of our immune system against tumor cells) that migrate to tumors where they destroy malignant cells. . In addition, it has been proven that chronic training prepares the tumor for the action of these lymphocytes by increasing the expression of molecules that activate them.
According to scientific evidence, we can assure that physical exercise has a clear preventive and therapeutic role in many types of cancer, although it has been fundamentally proven in breast and colon variants. Regarding the ‘dose’, it is recommended to follow the recommendations of the World Health Organization (accumulate at least 150 minutes per week of moderate-intense exercise) although it has been shown that up to 10 minutes of high intensity exercise could be sufficient to promote a certain antitumorigenic effect.
Helios Pareja and Alejandro Lucía are researchers at the European University. His research group is dedicated to understanding the biological mechanisms by which exercise helps prevent, and even treat, many diseases.
