Cancer patients might be able to slow the progression of their disease and even reverse tumour growth if they run regularly, according to tests conducted on mice that showed a 50 per cent reduction in tumour size in vermin given access to a running wheel.
A Danish study, published in Cell Metabolism today, found that a high-intensity workout like running produces a surge of adrenalin, which helps move cancer-killing immune (NK) cells toward lung, liver, or skin tumours in mice with cancer.
Researchers at the University of Copenhagen also discovered that exercise made muscles release a specialised signalling substance, which helped to guide the immune cells towards tumours.
A high-intensity workout like running produces a surge of adrenalin, which helps move cancer-killing immune (NK) cells toward lung, liver, or skin tumours.
"In our experiments, we tried to inject our mice with adrenaline to mimic this increase you see during exercise,” says the study’s senior author, Pernille Hojman from the University of Copenhagen.
“When we do that, we see that the NK cells are mobilised to the bloodstream, and if there's a tumour present, then the NK cells will find the tumour and home to it.
"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."
Research fellow at Australian Catholic University and Cancer Council Australia advisor, Associate Professor Prue Cormie, says these findings add greater weight to the current body of evidence highlighting how exercise can be used as medicine.
“We tend to dismiss exercise as a choice but there is a lot of research out now that says we can use exercise as medicine to manage disease and improve health,” says A/Prof Cormie who also acts as the chair of the Exercise and Cancer Group, Clinical Oncology Society of Australia.
“This research in particular shows that exercise acts to supercharge our body’s immune system. It also suggests that exercise may flood the body with its own cancer killing agents.
“So if you have cancer, this is something you can actually to help improve your tolerance of treatment and contribute to slowing the disease down.”
A/Prof Cormie explains that the key factor in the ‘supercharge’ effect tested in this study is exercise intensity.
That’s why other high quality aerobic exercises, like swimming and jogging, along with resistance training should have a similar effect on a body with cancer.
“What we do know from this evidence is that exercise has to be higher and harder than simply a stroll around the block.
“But intensity is relative: what exercise I do when I am going through treatment and my body is at a low physical capacity will be different than what I can do when I am healthy.
What we do know from this evidence is that exercise has to be higher and harder than simply a stroll around the block.
“So while exercise might not be an easy thing to do [if you have cancer], it will be something that cancer patients can tolerate both during and after treatment that they can benefit from.”
A/Prof Cormie recommends cancer patients consult the expertise of an exercise physiologist to receive an exercise plan that is safe, personalised and appropriate to follow.
But, she stresses, exercise is only meant to be an ‘add on’ to treatment and should never be used to replace chemotherapy or radiation.
“We can’t be throwing out the chemo and putting on the runners.
“Exercise is an adjunct therapy so it’s critical that patients receive standard cancer treatments as those treatments fight cancer.”
More research on the impact of high intensity exercise on humans with cancer is needed to determine to reach definitive results on how people can better manage their cancer and extend their longevity.