Compelling evidence suggests exercise is an important component of cancer prevention and care; slashing your risk of developing cancer, improving your chances of successful recuperation, and diminishing your risk of cancer recurrence.
A pattern revealed in these studies is that the longer you exercise, the more pronounced the benefits. Studies show that both men and women who exercise during their early years have a lower risk of cancer later in life.
But like most things in life, exercise must also be done in moderation and be balanced. There is a sweet spot and excessive exercise can cause its own set of issues, but most in the U.S. are far from being at risk for this problem.
According to a 2003 paper1 published in the journal Medicine & Science in Sports & Exercise,"more than 100 epidemiologic studies on the role of physical activity and cancer prevention have been published."
The authors note that:
"The data are clear in showing that physically active men and women have about a 30 to 40 percent reduction in the risk of developing colon cancer, compared with inactive persons …
With regard to breast cancer, there is reasonably clear evidence that physically active women have about a 20 to 30 percent reduction in risk, compared with inactive women.
It also appears that 30 to 60 min.· of moderate- to vigorous-intensity physical activity is needed to decrease the risk of breast cancer, and that there is likely a dose-response relation."
Adrenaline-Dependent Immune Cells Shrink Tumors
Most recently, research2,3,4 published in Cell Metabolism showed that active mice experienced a 50 percent reduction in tumor growth compared to inactive mice. The mechanism behind this rather remarkable occurrence is thought to be related to the rush of adrenaline that occurs during high intensity exercise.
The adrenaline helps circulate natural killer (NK) immune cells into tumors in the lung, liver, and skin, where they go to work to kill off and eliminate the cancerous cells.
To test this theory, the researchers injected mice with adrenaline. As predicted, they found that this caused NK cells to move into the bloodstream, and when a tumor was present, the NK cells would infiltrate it.
Then, to confirm the link between NK cells and tumor shrinkage, they used specially bred mice that do not have NK cells. In these mice, exercise had no effect on the tumors.
Blocking the flow of adrenaline had the same effect — the tumors remained, even when the mice exercised. As reported by Medical News Today:5
“The link between adrenaline-dependent mobilization of NK cells and tumor infiltration was identified as the immune signaling molecule, IL-6. Muscle tissue is known to release IL-6 during exercise.
What surprised the researchers was that adrenaline specifically called for IL-6 sensitive NK cells, and that the IL-6 molecules help to guide the immune cells to the tumors.” [Emphasis mine]