A recent study from the University of Turku in Finland reveals that just 30 minutes of exercise can boost the presence of tumor-killing white blood cells in the blood of breast cancer patients.
White blood cells are crucial components of our immune system, responsible for battling cancer, bacteria, and viruses. However, not all white blood cells are adept at destroying cancer cells; some may even facilitate cancer progression. Key cell types that combat cancer include cytotoxic T cells and natural killer cells, while those that support cancer growth include regulatory T cells and myeloid-derived suppressor cells.
Lead author, Doctoral Researcher Tiia Koivula from the University of Turku, Finland, explains, “The balance of various white blood cell types plays a significant role in determining whether the immune system fights or aids cancer. When there are more cancer-fighting cells than cancer-promoting cells in the tumor region, the body is better equipped to combat cancer.”
The study involved twenty newly diagnosed breast cancer patients who had not yet begun cancer treatments. These patients engaged in a 30-minute cycling session on a stationary bicycle. Blood samples were collected at rest before the exercise, during the workout, and post-exercise.
The blood samples were analyzed to determine the levels of different white blood cell types, comparing the numbers during exercise to those at rest.
The exercise led to an increase in several white blood cell types in the bloodstream. The most significant rise was observed in the number of cancer-fighting cytotoxic T cells and natural killer cells. Conversely, the levels of cancer-promoting regulatory T cells and myeloid-derived suppressor cells did not change.
The researchers also assessed the proportions of various white blood cell types relative to the total white blood cell count. They discovered a notable increase in the proportion of natural killer cells and a decrease in the proportion of myeloid-derived suppressor cells.
Koivula states, “We observed that the number and percentage of cancer-fighting cells rise in the bloodstream during exercise, while the proportion of cancer-promoting cells remains stable or decreases. Nonetheless, it remains uncertain whether these alterations in the blood also impact white blood cell counts in the tumor region.”
Furthermore, one hour post-exercise, most white blood cell types returned to their resting levels. Although the destination of these cells post-exercise remains unknown, previous studies suggest that cancer-fighting cells may migrate to the tumor site.
The researchers also investigated whether different types of breast cancer influenced the response of white blood cells to exercise. They noted that larger tumors correlated with less of an increase in natural killer cells, and estrogen/progesterone receptor-positive breast cancers showed a lesser boost in cytotoxic T cells compared to hormone receptor-negative cancers.
Koivula adds, “Our earlier study hinted at potential effects of breast cancer type on how exercise impacts white blood cells, prompting further investigation. However, the associations observed were not definitive, highlighting the need for caution in drawing conclusions. With current knowledge, exercise is beneficial for all cancer patients, a notion supported by our recent study.”
