High-intensity aerobic exercise can reduce the risk of metastatic cancer by 72%, a new study has found.
Researchers at Tel Aviv University discovered that running increases the glucose (sugar) consumption of internal organs, thus reducing the amount of energy available to tumors.
Led by Professor Carmit Levy of the Department of Human Molecular Genetics and Biochemistry, and Dr. Yftach Gepner of the School of Public Health, the research was recently published as a cover story in the prestigious Cancer Research journal.
“We decided to go deep inside the body, both in men and in mice,” Levy told The Media Line. “We let the mice run every day for a few minutes and we were analyzing their internal organs after physical activity. We were shocked to see that those tissues changed after chronic physical activity.”
“Muscles suck so much glucose when we run that all the body has to go into this fight over metabolite sources so all the organs, we hypothesize, become super metabolic,” she said.
The study looked at an animal model as well as human data. For the former, mice were trained to undergo a strict exercise regimen while the health of their internal organs was monitored before and after physical activity. Researchers found that aerobic activity significantly decreased the development of metastatic tumors in the mice’s lymph nodes, lungs and liver.
The human data was taken from an epidemiological study in which some 3,000 individuals were monitored for 20 years. It showed that there were 72% fewer cases of metastatic cancer in those who reported running at high intensity than in those who did not engage in physical exercise. Cancer is the leading cause of death in Israel in both men and women.
In both animal and human instances, scientists hypothesized that the lower metastatic cancer incidences are due to the enhanced rate of glucose consumption that comes as a result of exercising. This means that there is less sugar for tumors to feed on.
The study by Levy and Gepner specifically focused on people who ran for two hours a week or more.
“We didn’t check other types of physical activity,” Levy said. “Running has a protective effect and this is gained because the internal tissues become super metabolic.”
The next step, Levy said, will be for researchers to investigate exactly what types of physical activity provide the greatest protective effect. Her lab is also going to go deep into the physiology of brain metastases.
High-intensity exercise is defined as reaching at least 75% of the maximum heart rate for 30 minutes.
“Our results indicate that, unlike fat-burning exercise, which is relatively moderate, it is a high-intensity aerobic activity that helps in cancer prevention,” Gepner said in a statement that was shared with The Media Line. “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.”
The results show that healthy individuals should incorporate high-intensity elements into their existing fitness programs and also emphasize the importance of physical activity overall in cancer prevention, Gepner noted.
Previous studies have demonstrated that exercising reduces the risk of some types of cancer by up to 35%.
“Physical exercise, with its unique metabolic and physiological effects, exhibits a higher level of cancer prevention than any medication or medical intervention to date,” he said.