It’s pretty much impossible to find a study that undercuts the benefits of exercise. According to the National Cancer Institute (NCI), physical activity that exercises skeletal muscles (which is any aerobic exercise) has been linked to lower risk of cancer. Evidence has shown that exercise reduces the risk for cancers of the breast, colon, esophagus, kidney, stomach and uterus, according to many observational studies. In cancers of the breast, colon and prostate, research suggests that exercise may increase survival rates. Many explanations for how exercise may reduce cancer have been proposed, but the question has yet to be adequately answered.

How Exercise Beats Back Cancer

A new study from researchers at Edith Cowan University’s Exercise Medicine Research Institute in Joondalup, Australia, may have found that adequate answer. Exercising skeletal muscles produces proteins in the blood called myokines. Myokines play an active role in the body that may include strengthening of the immune system to fight inflammation.

Study details: To test the effect of myokines on cancer cells, the researchers recruited 10 men with prostate cancer who were being treated with androgen deprivation therapy. This therapy reduces male hormones that drive the growth of prostate cancer. The average age of the men was 73. All the men were overweight (obese).

All the men started a 12-week exercise program that included supervised muscle strengthening exercise (resistance training), aerobic exercise and protein supplements. Before the exercise program, muscle strength, bone density, weight and fat mass (the percent of body weight contributed by fat) were tested, and blood was drawn to measure the amount of myokine proteins. The blood was tested on live prostate cancer cells to see if myokines would affect cancer cell growth. The study is published in the journal Medicine & Science in Sports & Exercise.

At the end of the exercise program, all the measurements were repeated, and blood was taken again to measure myokine levels and to test the blood on live prostate cancer cells. Key results included…

  • Body weight and fat mass were reduced.
  • Strength increased.
  • Levels of blood myokines increased.
  • The growth of live prostate cancer cells exposed to the after-exercise blood showed a significant reduction compared to the before-exercise blood.

Exercise Makes Myokines Stop Cancer

Myokines slowed or stopped the cancer cells from growing. The myokines also stimulated immune system cells to attack the cancer cells, resulting in cancer cell death. Androgen deprivation therapy has a side effect of reducing muscle mass and replacing muscle with fat. The exercise program reversed that effect.

Although this study focused on prostate cancer, the most common cancer in men after skin cancer, the research team believes that myokines produced by exercise will have similar suppressing effects on other cancers as well.

For more information on building the right exercise program during cancer: Visit the cancer resource website of the American Society of Clinical Oncology at

Source: Study titled “Myokine Expression and Tumor-Suppressive Effect of Serum Following 12 Weeks of Exercise in Prostate Cancer Patients on ADT,” by researchers at Edith Cowan University, Joondalup, Australia, published in Medicine & Science in Sports & Exercise.

Related Articles