High-intensity exercise may help fight cancer because the rise in adrenaline activates the cells that destroy tumors, a study published in the journal Cell Metabolism said.
A research team led by Pernille Hojman, of the University of Copenhagen, reached this conclusion after observing that mice running on a wheel are better able to fight tumors than less active peers.
The surge in adrenaline that comes with a high-intensity workout helped move cancer-killing immune, or NK (natural killer), cells toward tumors.
“It is known that infiltration of natural killer immune cells can control and regulate the size of tumors, but nobody had looked at how exercise regulates the system,” Hojman said.
Researchers injected the mice with adrenaline, like the hormone released by exercise, and observed how NK cells moved in the blood stream to attack lung, liver or skin tumors implanted in the animals.
“As someone working in the field of exercise and oncology, one of the main questions that cancer patients always ask is: How should I exercise?” Hojman said.
“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 (adrenaline) surge and hence recruitment of NK cells,” the scientist said.
The research team said further study was required to determine the impact of exercise on metastasis and longevity, and also to learn whether the effect observed in mice would apply to humans.