A new study from the University of Turku in Finland has found that just 30 minutes of exercise can increase the amount of tumor-killing white blood cells in the bloodstream of breast cancer patients.
White blood cells…are they working for you or against you?
White blood cells, the cells of our immune system, are responsible for fighting cancer, bacteria, and viruses. However, not all types of white blood cells kill cancer cells, and some can support cancer growth.
Cytotoxic T cells and natural killer cells are the most important types of immune cells when it comes to destroying cancer cells, while the types that support cancer growth include regulatory T cells and myeloid-derived suppressor cells.
“The balance of different types of white blood cells determines whether the immune system works to destroy cancer or support it,” the study’s lead researcher, Dr. Tiia Koivula from the University of Turku in Finland, told EurekAlert. “If there are more cancer-destroying cells than cancer-supporting cells in the tumor area, the body is better able to fight cancer.”
voltage measuring bike
The study, the results of which were published in the journal Frontiers in Immunology at the end of last June, involved 20 patients who were recently diagnosed with breast cancer and therefore had not yet started treatment.
During the study, patients exercised on an ergometer bike for 30 minutes at a resistance of their own choosing. Blood samples were taken from the patients at rest before, during and after exercise. The blood samples were analyzed to calculate the amount of different types of white blood cells, and the amounts measured during exercise were compared to those measured at rest.
During exercise, the amount of several types of white blood cells in the bloodstream increased, and the increase in the number of cytotoxic T cells and natural killer cells that destroy cancer was the largest.
On the other hand, the amount of regulatory T cells and myeloid-derived suppressor cells, which support cancer, did not change. The researchers also examined the proportions of different types of white blood cells relative to the total number of white blood cells, and found that the proportion of natural killer cells increased significantly, and the proportion of myeloid-derived suppressor cells decreased.
“We found that the number and proportion of cancer-destroying cells increased in the bloodstream during exercise, while the proportion of cancer-supporting cells remained the same or decreased,” says Koivula. “However, it remains unclear whether these changes seen in the bloodstream lead to changes in the number of white blood cells in the tumor area.”
Breast cancer type.. How does it affect the immune cell response?
The researchers wanted to see if different types of breast cancer affected the response of white blood cells to exercise. They found that the larger the tumor, the smaller the increase in the number of natural killer cells. And if the breast cancer was estrogen and/or progesterone receptor positive (meaning the cancer cells express a protein on their surface that acts as a receptor for these hormones), the increase in the number of cytotoxic T cells was smaller than if the cancers were hormone receptor negative (cancers that do not express these receptors).
Sports for all
“In our previous study, we found small hints that the type of breast cancer might influence the effects of exercise on white blood cells, which is why we wanted to examine these effects more deeply,” says Koivula. “However, the relationships we found were not very strong, so definitive conclusions cannot be drawn from the results. According to current knowledge, exercise is beneficial for all cancer patients, and our latest study supports this belief.”