Study: Aerobic exercise lowers risk of metastatic cancer

According to a new study, aerobic exercise can lower the likelihood of cancer metastatic spread by 72%.

According to the researchers, the quantity of glucose (sugar) absorbed by internal organs increases during severe aerobic activity, reducing the amount of energy accessible to the tumour.

Two TAU Sackler Faculty of Medicine researchers led the study: Prof. Carmit Levy from the Department of Human Genetics and Biochemistry and Dr. Yftach Gepner from the School of Public Health and the Sylvan Adams Sports Institute. Prof. Levy emphasises that the new study has resulted in a very important discovery by combining scientific know-how from different schools at TAU, which may help prevent metastatic cancer – Israel’s leading cause of death.

The paper was published in the prestigious journal Cancer Research and chosen for the cover of the November 2022 issue.

Prof. Levy and Dr. Gepner: “Studies have demonstrated that physical exercise reduces the risk for some types of cancer by up to 35 percent. This positive effect is similar to the impact of exercise on other conditions, such as heart disease and diabetes. In this study we added new insight, showing that high-intensity aerobic exercise, which derives its energy from sugar, can reduce the risk of metastatic cancer by as much as 72 percent. If so far the general message to the public has been ‘be active, be healthy’, now we can explain how aerobic activity can maximize the prevention of the most aggressive and metastatic types of cancer.”

The study combined data from healthy human volunteers investigated before and after jogging with an animal model in which mice were trained under a stringent exercise schedule. Human data from an epidemiological research that followed 3,000 people for nearly 20 years revealed that participants who reported frequent high-intensity aerobic activity had 72 percent less metastatic cancer than those who did not engage in physical activity.

The animal model had a similar result, allowing the researchers to uncover the underlying process. They discovered that aerobic activity dramatically decreased the growth of metastatic tumours in the lymph nodes, lungs, and liver by sampling the internal organs of physically fit animals before and after physical exercise, as well as after the injection of malignancy.

The researchers hypothesized that in both humans and model animals, this favorable outcome is related to the enhanced rate of glucose consumption induced by exercise.

Prof. Levy: “Our study is the first to investigate the impact of exercise on the internal organs in which metastases usually develop, like the lungs, liver, and lymph nodes. Examining the cells of these organs we found a rise in the number of glucose receptors during high-intensity aerobic activity – increasing glucose intake and turning the organs into effective energy-consumption machines, very much like the muscles. We assume that this happens because the organs must compete for sugar resources with the muscles, known to burn large quantities of glucose during physical exercise. Consequently, if cancer develops, the fierce competition over glucose reduces the availability of energy that is critical to metastasis. Moreover, when a person exercises regularly, this condition becomes permanent: the tissues of internal organs change and become similar to muscle tissue. We all know that sports and physical exercise are good for our health. Our study, examining the internal organs, discovered that exercise changes the whole body, so that the cancer cannot spread, and the primary tumor also shrinks in size.”

Dr. Gepner added: “Our results indicate that unlike fat-burning exercise, which is relatively moderate, it is a high-intensity aerobic activity that helps in cancer prevention. If the optimal intensity range for burning fat is 65-70 percent of the maximum pulse rate, sugar burning requires 80-85 percent – even if only for brief intervals.

For example: a one-minute sprint followed by walking, then another sprint. In the past, such intervals were mostly typical of athletes’ training regimens, but today we also see them in other exercise routines, such as heart and lung rehabilitation.

Our results suggest that healthy individuals should also include high-intensity components in their fitness programs. We believe that future studies will enable personalized medicine for preventing specific cancers, with physicians reviewing family histories to recommend the right kind of physical activity. It must be emphasized that physical exercise, with its unique metabolic and physiological effects, exhibits a higher level of cancer prevention than any medication or medical intervention to date.”