It might surprise you to hear that high-intensity interval training could help fight cancer, but recent findings suggest just that. While HIIT programs like Sprint 8 have been proven to help burn fat and build muscle through the release of growth hormone, they also achieve an adrenal response that strengthens the immune system in a way that has been shown to target tumors in mice.

Scientists have known that tumor-killing NK immune cells can attack tumors and reduce their size — if they can find their way to the correct site in the body. In 2016, researchers demonstrated in a major, first-of-its-kind study that exercise intense enough to release a surge of adrenaline into the body of mice will also cause the body to direct cancer-killing immune cells to the site of tumors planted in the mice.

During the study, some mice were blocked from their sprinting wheel and could not do sprint cardio. These mice did not show reduced tumor size. However, the mice that did sprint cardio reduced tumor size by 50 percent. Researchers credit the adrenaline surge from their sprint cardio for directing the cancer-killing immune cells to the tumors (Line Pedersen. (February, 2016) Voluntary running suppresses tumor growth through epinephrine- and IL-6-dependent NK Cell mobilization and redistribution. Cell Metabolism).

Study spokesperson, Dr. Pernille Hojman, reported:

That was actually a big surprise to us. 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?”

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 adrenaline surge and hence recruitment of NK cells, (Cell Press. (2016, February 16). Running helps mice slow cancer growth. ScienceDaily. Retrieved February 18, 2016 from

In another experiment, Dr. Hojman’s research team injected mice with either epinephrine or saline. Epinephrine, which causes a surge of adrenaline, was shown to reduce the growth of tumors by 61% in the mice that didn’t do sprint cardio. However, this was not as impressive as the mice that reduced their tumors by 74% with natural sprint cardio exercise.

The white blood cells of the body’s immune system produce IL6 (short for Interleukin 6), and this regulates cell growth. It also plays an important role in immune response. This study suggests that when you use sprint cardio like the mice did, you could attack tumors and reduces their size by 50 percent. Any way you cut it, this is very positive.

A physician friend said to me once, “You know what you are doing to people with Sprint 8, don’t you? You are giving them a self-induced fever three-days-a-week.” While fevers don’t feel good, they are induced by the body for a good reason. The hypothalamus, the same gland that tells the pituitary gland to release growth hormone, controls body temperature and raises it to fight infections (Dinarello CA. (2004) Infection, fever, and exogenous and endogenous pyrogens: some concepts have changed. J Endotoxin Res.10(4):201-22).

The hypothalamus turns up the heat to help the body fight off sickness. Since Sprint 8 also turns up the heat three days a week, does this mean that Sprint 8 could be used to fire preemptive strikes at infections that enter the body? There isn’t a definitive answer yet, but the possibilities are intriguing.

So can HIIT programs like Sprint 8 play a role in killing cancer tumors in humans? These recent studies suggest that it’s possible, but only more dollars for exercise research will tell us for sure. In the interim, I’m doing Sprint 8 three times a week.

Phil Campbell

“Sprint 8 is a tried and true workout that can rapidly and radically change your body for the better. It’s simple. It’s effective. And you’re going to love what it does to your body.”