The list of benefits for aerobic exercise is long but new research makes one stand out with eye-popping numbers. A study conducted at Tel Aviv University in Israel found the risk of metastatic cancer was cut by 72% through intense aerobic exercise.
Scientists believe this is because the aerobic exercise increases the consumption of glucose (sugar) by the internal organs. That in turn reduces the amount of energy available for tumor growth.
The work done by Professor Carmit Levy and Dr. Yftach Gepner was highlighted in a recent edition of the journal Cancer Research. It is considered extremely important because metastatic cancer, the type that spreads from one part of the body to others, is the leading cause of death in Israel according to TAU statistics.
"Studies have demonstrated that physical exercise reduces the risk for some types of cancer by up to 35%," Dr. Gepner said. "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%. 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 had two components – one human and one animal. The human portion tracked 3,000 individuals over a 20-year period and found 72% less metastatic cancer in participants who reported high-intensity aerobic activity at a regular interval compared to those who did not regularly exercise.
The animal model involved mice trained with a strict exercise regimen and produced a similar outcome. Researchers were able to take samples from the internal organs of the physically fit animals before and after exercise and after cancer was introduced. The aerobic exercise, which triggered higher rates of glucose consumption, significantly reduced the tumor development in the lymph nodes, lungs and liver of the mice.
Prof. Levy stated, "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," Professor Levy stated. "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% of the maximum pulse rate, sugar burning requires 80–85%—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."