Though I think that common sense probably tells us that exercise aids cancer treatment (heaven knows that I felt better when I did restorative yoga or took walks when I was sick), but when there is science behinds something…well, then it REALLY seems to matter.
Mark W. Dewhirst, the Gustavo S. Montana Professor of Radiation Oncology at Duke University School of Medicine has recently conducted a study involving the effects of aerobic exercise on breast cancer tumors. The study was conducted on mice and resulted in a major Shining Moment! The results showed that aerobic exercise slowed the growth of breast cancer tumors in mice and made the cancer tumors more sensitive to chemotherapy. This tells us that there is a possibility that exercise may change the biology of some malignant tumors by making them potentially easier to treat.
How you ask? Well, scientists have known for quite some time that tumors have the ability to create their own ecosystem within the body. As a tumor grows, it sends out signals that prompt the body to create additional blood vessels to provide the growing tumor with more oxygen and blood flow.
Some tumors, however, begin to proliferate so much that they begin to choke one another, reducing the amount of blood supply and oxygen to the tumor. You would think that this would ultimately kill the tumor (since it is not receiving a good amount of blood flood or oxygen), however, this is not the case. Instead, the tumor becomes hypoxic, which means that it exists in an environment with little oxygen. Hypoxia actually makes tumors relatively resistant to treatment because there is so little blood flow and oxygen going into the tumor. Since chemotherapy and radiation work much better in conjunction with oxygen, the hypoxic tumors tend to resist treatment.
In this study, scientists divided mice into two groups — one group remained sedentary after surgery and the other ran at will on wheels in their cages. In both groups, the tumors took hold and grew inside their bodies. However, the tumors in the running mice grew significantly slower. Testing showed that the blood vessels feeding the tumors in the running mice were healthier than in the sedentary mice. As a result of this, the runners’ tumors were less hypoxic.
Using another group of mice, scientists divided them into two groups and tested one group’s response to receiving chemotherapy treatment while remaining sedentary and the other group’s response to receiving chemotherapy treatment and exercising. After 12 days, the results showed that exercise and chemotherapy each had slowed tumor growth. While the mice that exercised did show smaller tumors than did the sedentary mice, the mice who had both the treatment and exercise had the smallest tumors.
This shows that exercise, known for increasing the flow of oxygen-rich blood to tissues made the breast cancer tumors easier to kill by making the tumors less hypoxic and paradoxically… healthier. When the tumors were receiving more oxygen and blood flow, the treatment was able to easily penetrate the tumors and ultimately make them smaller.
Of course this study was only conducted on mice and therefore, there is no scientific evidence showing that the results of this study would be the same if conducted on humans.
When I was going through treatment there were days where I felt like I couldn’t stand and on those days I would advise you to rest. But there will be days where your body can handle movement and on those days I would recommend gathering every bit of mental and physical strength to go for a walk or doing yoga. Getting yourself to move is not only beneficially for your body but also for your mind as well.
As always consult with your doctor about what you are doing and when! Happy Trails!