A Careful Look at Physical Activity,
Heart Disease and Survivors
Lee Jones, PhD
Early studies of physical activity’s effects during cancer treatment are showing encouraging results. Here is what one researcher is finding out about exercise and side effects from cancer treatment.
Lee Jones, PhD, of the Memorial Sloan Kettering Cancer Center in New York, is investigating ways to combat serious side effects of cancer treatment using exercise techniques. But he is proceeding with great caution because the fatigue that many cancer patients experience during chemotherapy may indicate cardiovascular problems.
“Chemotherapy can damage the heart muscle, as well as other muscles in the body,” he explains. This damage can impair the body’s ability to use oxygen. It can also directly impact the heart muscle, leading to cardiovascular disease.
Studies of mortality for survivors who have had certain types of cancer – breast and prostate, for example – reveal that cardiovascular disease is the main cause of death. Even if cancer treatment is successful, heart problems may still appear.
In fact, cardiovascular disease occurs at a much younger age in cancer survivors than in those who have never had cancer. Dr. Jones explains that this is due to premature aging, a direct side effect of cancer therapy.
Tailoring Exercise Prescriptions
According to Dr. Jones, 12 weeks of chemotherapy is equivalent to 10 years of aging. Fortunately, he says, “Exercise training during cancer treatment can completely mitigate the premature aging effect.”
Exercise training should be thought of as a drug, he explains, and like any drug, the amount and type should be determined individually for each patient, working closely with a doctor and exercise specialist. Dr. Jones’s studies have used activities ranging from running and cycling to yoga and weight lifting.
In studies of cancer survivors, Dr. Jones and his team have seen a 25 percent increase in fitness level with just 15 weeks of exercise training. Ordinarily, one would expect only 15-20 percent improvement in fitness over this length of time. The increased fitness level translates directly to a longer life expectancy.
How Exercise Protects
One way exercise helps protect against cancer is by helping to control weight, but there are other ways. Exercise also reduces levels of insulin and estrogen in the blood as well as certain growth factors, all of which encourage tumor growth. Physical activity can also affect inflammation, a key part of the cancer development process.
Could exercise be an effective treatment for cancer itself? Dr. Jones says very preliminary evidence indicates that it might. Someday, an exercise prescription might even be part of a cancer treatment program.
“Much more work needs to be done in this area,” he says, but the preliminary evidence is clear: exercise can help at all stages of the fight against cancer.