How exactly does physical activity affect the immune system?
Science says that exercise boosts the immune system over the long term. But it can also make you sick in the short term.
The fitness expert says: “Intense exercise temporarily lowers your immune system,” says Bishop. “That’s why almost all marathoners, for example, get sick a few days after running a race. And while you’re working out and training your body harder, it may increase the risk of higher free-radical formation and oxidative stress. While that all sounds negative, the good effects of exercise clearly outweigh the bad.” Bishop says a healthy lifestyle and diet balances and supports the immune system.