Answer:
Physical exercise promotes the release of cytokines, increases the circulation of white blood cells and the recruitment of immune cells to injured/infected sites
Step-by-step explanation:
Physical exercise is fundamental maintain a healthy immune system. It has been shown that exercise 1-promotes the releases of pro- and anti-inflammatory cytokines which are capable of modulating the growth and activity of immune system cells and blood cells, 2-increases the ongoing exchange of white blood cells (i.e., leukocytes) between the circulation and tissues, and 3-stimulates the recruitment of highly specialized immune (e.g., natural killer cells and T cells) to injured/infected sites in order to identify microorganisms (e.g., bacteria, viruses and fungi) or substances that are potentially harmful and wipe them out. Moreover, it is also important to highlight that excessive physical exercise can deplete the immune system and therefore increase the risk of infection.