Exercise and Cancer
Oncologists treating cancer patients often recommend exercise, in addition to all the other treatments provided. It is generally thought that improving overall health and mental outlook might be beneficial for survival. Until recently, the exact role that exercise played in improving life for cancer patients was unknown and unexplored.
Up to 20 years ago, it was not known that exercising muscles excreted anything at all. Now there is a whole new and rapidly growing field called exercise oncology: the application of exercise medicine in cancer. It is now known that exercising/contracting skeletal muscles secrete a wide range of biologically active proteins named myokines. These myokines differ from one another and are spread throughout the body by the blood, where they bind with specific receptors. It is thought that this may be the method that allows exercise to provide its many well-known benefits.
A study in 2021 focused on prostate cancer and was published in the prestigious journal Medicine and Science in Sports and Exercise. Fifty-four men, mean age 73, were contacted. All but ten were eliminated because they were too ill to exercise, or cancer had spread to the bone. The ten were put on a 12-week program of supervised resistance training and voluntary aerobic exercise. The workouts were quite intense and progressive. Blood was collected before and after the program. The serum containing five different types of myokines was isolated. The next step was to apply the serum to cancer cells in the lab. The cancer cells used were not from the men in the study but were from a standard line of prostate cancer cells available for this type of research; this is the accepted way to test resistance to cancer growth.
When the serum collected from the men after the 12-week exercise program was applied to the cancer cells, it revealed a marked effect on decreasing cell growth, proliferation, survival, and migration. This effect was not present in the serum collected before exercise. This astounding finding is, of course, in vitro. It is not a study of what happens in a living body: in vivo. Another in vitro study used one particular myokine called irisin and produced the same results.
Epidemiological studies in this field have long found an inverse association between physical activity and disease progression. A study in 2011 compared men who exercised more than three hours per week to those who worked out less than one hour and found a 61% lower risk of prostate cancer death among the exercisers and a 57% lower risk of progression.
The finding that exercising muscles secretes a flood of biologically active substances, some of which may inhibit cancer, is indeed BREAKING NEWS. It is a wonderful finding and provides one more big reason to keep those muscles working.