When your heart is healthy and strong, it pumps blood more efficiently to circulate it throughout your body. Along with oxygen and all the nutrients it carries, your blood also contains immune cells called neutrophils that roam throughout your veins and capillaries, looking for any warning signs of infection or malignancy.
When you’re at rest, these cells tend to cluster near your lymph nodes and in other parts of the body; if they’re in circulation, they leave a chemical trail by which “killer” T cells can find them if a problem is found.
Exercise enhances your immune system in other important ways. Regular exercise has been linked to keeping a good supply of fresh T cells to respond to any invaders, while flexing and contracting your muscles sends lots of proteins pouring into your bloodstream, which have cascading effects on your immune cells.
While any movement that bolsters your cardiovascular health is going to be good for immunity as well, there are some types that may be especially effective at fortifying your immune system’s defenses:
Walking
This low-impact exercise is easy to take up, keeps your arms and legs in constant motion to boost circulation, and 20 minutes of it a day has been found to lower people’s chances of falling ill with a communicable disease.
Side-to-side lunges
These and similar movements have been found to keep your lymph system open and flowing, which also helps your immune cells circulate in ways that are beneficial to you.
Pilates
The low-impact movements of this program, many of them involving some degree of inversion, are gentle enough to get cells circulating through your lymphatic system without leading to the kind of micro muscle tears that are one of the goals of strength training, but must also be repaired by your body, adding to its healing load.