Running May Help Shrink Tumors in Cancer Treatment

The combined impact of anti-cancer treatments and exercise holds promise for shrinking tumors.

Active mice that used a running wheel were able to shrink tumors by 50% compared with less active mice in a recent study.

It’s been previously shown that natural killer (NK) immune cells are able to regulate the size of tumors. However, it had yet to be determined what kind of effect exercise has on regulating the system.

"In our experiments, we tried to inject our mice with adrenaline to mimic this increase you see during exercise, and when we do that we see that the NK cells are mobilized to the bloodstream, and if there's a tumor present then the NK cells will find the tumor and home to it," said senior study author Pernille Hojman.

Exercise and Cancer Treatment

The study used mice that had been depleted of NK cells in order to show increased NK cells could directly contribute to the reduction of the tumor.

Although it’s been found that IL-6 gets released from muscle tissue during exercise, the results of the study show that adrenaline is associated with IL-6 sensitive NK cells and that IL-6 molecules were able to guide immune cells to the tumors.

"That was actually a big surprise to us," Hojman said. "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."

Further research is needed on the effects exercise has on metastasis, longevity, and how it affects humans. Researchers also want to look into the combined impact of anti-cancer treatments and exercise on tumors.

"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? Can we do anything?" 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 surge and hence recruitment of NK cells."