It is known that physical activity reduces the risk of cancer. And now we know how

Decades of research have shown that physical exercise helps fight cancer. If you are physically active, you can reduce the risk of cancer. If you are already suffering from cancer, exercise can slow down the development of the tumor. And if you have overcome cancer by spending hours in the gym, you may slow down or even prevent a recurrence of the disease.
But the mechanism of how exercises help fight cancer has never been clear enough. According to a new study involving mouse tests published in Cell Metabolism , the key may be in the levels of adrenaline that exercise is causing.

Researchers at the University of Copenhagen put a running wheel in the cells of a group of mice, and those in another group did not. As the mice love to run, the wheel group exercised much more than the other group.

Then one of three types of cancer was induced in the mice from the two groups by: injecting melanoma cells under the skin to induce skin cancer, injecting melanoma cells into the tail for inducing lung cancer or diethylnitrosamine injection to develop liver cancer.

Four weeks later, in mice that had access to the jog wheel, the consequences were much better than the mice they did not have. Among the mice that were exerted, only one-third of the diethylnitrosamine injected liver cancer developed. By comparison, three-fourths of the sedentary lifestyle mice developed cancer. All mice injected with melanoma cells developed the disease, but in mice with high physical activity the tumors were smaller.

Tumor analysis showed that the mice that were exerted had more than two types of cancer cells killing cancer - doubled T-cells and five times more natural killer cells (NK-lymphocytes). However, when intervention was interrupted to stop T-cell production, physically active mice continued to have smaller tumors than others. But when researchers stopped producing natural killer cells, both groups had tumors of similar size. Therefore, natural killer cells are those that confer the advantage of active mice and not T cells.

Running produces adrenaline, and adrenaline is known to increase the production of natural killer cells. So the researchers injected with adrenaline half the mice that did not exercise and the other half with saline. In those who received saline, no difference was observed. In those who received adrenaline, there was a decrease in tumor growth, but the progress was not as great as that of physically active mice.

Scientists also tested with another substance called interleukin-6, which had elevated levels in the mice that were practicing. When the same experiment of injection of inactive mice with adrenaline was repeated with the addition of interleukin-6, it was found that the decrease in tumor growth was the same as in the active mice.

Of course, mice are not humans, but scientists believe that this mechanism works for people. They are currently exploring the potential for the use of adrenaline and interleukin-6 as anticancer drugs. What in the lesson for all of us? Well, now we have another reason to train.