Running has a lot of health benefits, but a new animal study has found that running can potentially be beneficial in fighting cancer.
According to the study, published in the journal Cell Metabolism, vigorous exercise can help slow the growth of cancerous tumors in mice. Researchers believe that exercise could have similar benefits for people when it comes to fighting cancer.
Researchers tested the effect that exercise would have on several types of mouse cancers, including cancers of the skin, liver, and lungs. The mice with cancer were given running wheels and the development of their cancer was monitored.
The mice ran from four to seven kilometers each day and researchers discovered they were better able to fight off their cancer. Growth of the cancerous tumors was slowed by up to 60 % compared to inactive mice.
As well, exercising helped prevent new tumors from developing. The findings of the study showed that exercising helped the immune system slow the progression of cancer, but it did not shrink tumors that had already developed.
“It’s the first time we’ve shown that exercise can directly control the growth rate of tumors,” said Pernille Hojman, co-author of the study and a researcher at the University of Copenhagen.
The researchers found that the cancer-fighting effects were due to the adrenaline, which is released during high-intensity exercise. Adrenaline was found to move natural killer (NK) immune cells through the body. NK cells help inhibit the growth of tumors and fight cancer.
Adrenaline is released in high-intensity exercise, as well as in situations where people feel threatened or at risk. It is often called the “fight or flight” hormone.
In the study, the researchers also found that an immune signaling molecule called IL-6, which is released from the muscles during exercise, helped direct the NK cells to the cancerous tumors.
“That was actually a big surprise to us,” said Hojman. “In this study we show that the exercise-induced IL-6 seems to play a role in homing of NK cells to the tumor and also in the activation of those NK cells.”
To ensure that NK cells were responsible for the cancer-fighting benefits, the researchers also tested mice that were depleted of their NK cells. Even with exercise, the mice without NK cells did not experience any reduction in the growth of their tumors. As well, blocking the effects of adrenaline also removed the cancer-fighting benefits of the exercise.
These findings indicate that adrenaline, NK cells, and IL-6 can all work together to help fight cancer. However, all of these elements are required for the benefits.
Hojman says that these findings indicate that it may be helpful for cancer patients to perform high-intensity exercises. While it was previously unknown whether exercise should be recommended for people with cancer, the results of the study show that it has clear benefits.
“While it has previously been difficult to advise people about the intensity at which they should exercise, our data suggest that it might be beneficial to exercise at a somewhat high intensity in order to provoke a good epinephrine surge and hence recruitment of NK cells,” said Hojman.
Source for Today’s Article:
Pederson, L., et al., “Voluntary Running Suppresses Tumor Growth through Epinephrine- and IL-6-Dependent NK Cell Mobilization and Redistribution,” Cell Metabolism, 2016; doi: 10.1016/j.cmet.2016.01.011, last accessed February 18, 2016.