A new study published in the journal Cancer Research suggests aerobic exercise could help reduce the risks of certain cancers from developing or recurring.
While that finding is far from novel — it’s well established that exercise has protective effects against cancer — researchers from Tel Aviv University in Israel investigated the mechanisms by which aerobic exercise affected tumours and their growth.
Looking at health data from 2,734 people over a 20-year period, the researchers determined that those who engaged in regular high-intensity aerobic workouts like running had 72 per cent fewer metastatic cancers than those who were sedentary.
Then, in the study’s second phase, they monitored mice engaged in aerobic exercise before and after being injected with melanoma cancer cells.
What they found was that mice that engaged in the regular exercise had fewer metastatic tumors than the sedentary animals.
After analysing protein expression in their mouse model, the researchers observed metabolic changes related to glucose use in the active mice. The researchers said this suggests that exercise was creating glucose demand on internal organs, thus “starving” cancer cells of necessary fuel to proliferate.
“The study provides good evidence that regular aerobic exercise results in reprogramming those metabolic pathways associated with glucose utilisation — which they refer to as a ‘metabolic shield,’” said James Hicks, a professor of ecology and evolutionary biology at the University of California Irvine, who was not involved in the study.
“This exercise-induced ‘reprogramming’ of healthy tissues increases competition for glucose (a primary fuel for cancer cells), thus ‘stealing’ vital energy from cancer cells,” Hicks told Healthline. “It would be interesting to determine if this redistribution is associated with changes in blood flow to tumors since blood flow is delivering glucose to the cells.”
“The paper provides insights into the underlying mechanisms of the links between exercise and cancer progression,” he added. “Additional mechanistic studies are needed to determine if the volume of exercise — intensity and duration — can be optimised for a broader population of cancer patients.”
High-intensity exercise such as running might be an ideal form of exercise for some people, but other exercises like swimming, rowing, and cycling can also provide a similar intensity with less strain on the joints.
High intensity also might not be possible depending on age and other factors. For these people, even moderate exercise still has a protective effect against cancer, Hicks said.
“Hundreds of epidemiological studies, comprised of millions of participants, provide strong evidence that regular, daily activities like brisk walking significantly reduce the risks of many cancers,” he said. “These results show 10 to 20 percent risk reductions for bladder, breast, colon, endometrial, esophageal adenocarcinoma, and renal and gastric cancers.
“High-intensity exercise may be challenging for many cancer patients. However, moderate exercise levels that will raise your heart rate to 50 to 70 percent of the maximum heart rate are achievable,” he added.
There are psychological benefits to exercise on top of the potential medical ones, which can also improve outcomes and quality of life.
“Exercise may well be the singular most proactive and self-empowering way a patient can support their cancer journey,” said Joy Puleo, the director of education at wellness company Balanced Body and a cancer survivor.
“All other treatments are medical and require varying levels of expertise,” Puleo told Healthline. “Here, a patient can have a measure of control over self and possible outcomes. It is also a way to include peers and engage their support network.”
She suggested picking any aerobic exercise you’d like, as long as you can do it regularly and keep challenging yourself.
“Move. Find an exercise that works for you and use it to challenge ‘the system.’ A good exercise program, regardless of choice, should have elements of challenge associated with it,” Puleo said. “For aerobic work, get on a bike, walk and when you can walk a hill or for a short period, walk faster. A trampoline is a fun way to get the heart rate up and laugh at the same time. My favorite? Go dancing.”