Rhonda Patrick· PhD
The reason for this temporary decline in immune cell numbers in the bloodstream is because immune cells travel to other tissues like the lungs because they go there to look for infections.
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The reason for this temporary decline in immune cell numbers in the bloodstream is because immune cells travel to other tissues like the lungs because they go there to look for infections.
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During exercise, some immune cell numbers in the bloodstream increase dramatically but decrease immediately after exercise and then return to normal several hours later.
The increase of immune cells is due to the immune cells being pulled off of the edges of blood vessels by the increased blood flow and pressure. Afterwards, the decrease is due to redistribution of immune cells to various tissues and out of the bloodstream. This has been shown in mice where fluorescent cell tracking showed immune T-cell numbers rise during bouts of exercise, but then were redistributed primarily to the lung and other areas like the small intestine. If anything, the immune surveillance is actually heightened during the period where a few immune cells are measured in the blood. As a result, the mechanism behind the J-shaped curve of respiratory infection and exercise duration is not due to the number of immune cells in the blood.