30 minutes of exercise temporarily raises breast cancer-killing cells in the blood
CANCER DIGEST – July 13, 2024 – A new Finnish study has found that 30 minutes of exercise on a stationary bike increases the number of tumor-killing white blood cells, while decreasing the number of cells that promote tumor growth. The findings were published in the June 24, 2024 journal Frontiers in Immunology.
The small study led by doctoral researcher Tiia Koivula at the University of Turku, Finland, involved 20 breast cancer patients who had just been diagnosed and had not started treatment. The patients pedaled a stationary cycle for 30 minutes at a resistance level of their own choosing. Blood samples were taken before, during and after the exercise.
Analysis of the blood samples measured the different types of white blood cells and compared the exercise levels of the cells to the resting levels. They found that during the exercise several different types of white blood cells increased in the bloodstream during the exercise, while the number or regulatory T cells and myeloid derived suppressor cells did not change.
They also analyzed the ratios of the different types of cells and found that the number of natural killer T cells increased significantly compared to the myeloid suppressor cells, which decreased during exercise.
“We found that during the exercise, the number and proportion of cancer-destroying cells increases in the bloodstream,” Koivula said in a press release, "while the proportion of cancer-promoting cells either stays the same or decreases. However, it is still unclear whether these changes seen in the bloodstream also lead to changes in the white blood cell counts in tumor area."
The researchers also found that the number of white blood cells decreased back to resting levels an hour after exercise. While it is not known where the increased white blood cells go, laboratory studies have shown that the cancer-killing cells tend to migrate to the tumor area.
The analysis also showed that the type of breast cancer has an affect on the level of white blood cells raised by exercise. In patients with larger tumors and those that were hormone receptor positive, the exercise produced lower affect on white blood cells and smaller increases in the number of cancer killing T cells.
The research team concludes that exercise may benefit all cancer patients, but how much and how long the effect exercise has on tumors remains to be seen.
Source: University of Turku, Finland press release
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