How Exercise Benefits the Immune System

By Jennifer

Cancer is caused by a failure of your immune system to fight off mutant cells that in turn build tumors in the body. This is why it is so important to have a healthy immune system in the first place.



First off let’s look at some of the factors that cause immune system dysfunction. This includes age, cigarette smoking, stress, poor nutrition, lack of sleep and over training.



Many studies have shown that regular moderate exercise boosts immunity and in turn prevents cancer. The key is consistency and being “sane about it.”  Working out or walking for an hour every day is going to leave your immune system in healthier shape than slogging it out for three hours every day.



During moderate exercise immune cells travel through the body more quickly and are better able to kill bacteria and viruses. After exercise ends, the immune system generally returns to normal within a few hours.



However if you exercise too hard the body goes into an emergency mode that leaves you less resistant.  Intense exercise seems to cause a temporary decrease in the functioning of the immune system. Research has found that during intense physical exertion, the body produces certain hormones that temporarily lower immunity.


Exercise also helps reduce psychological stress and cancer patients are under a great deal of duress. Exercise can help lower the levels of cortisol and adrenalin in the blood.



One study at Appalachian State University found that the immune system improved  in individuals who simply took a walk for forty minutes a day. These individuals had half as many sick days due to colds and flues.



The same study found that athletes who exercised hard for more than ninety minutes were vulnerable to disease for over 72 hours after they exercised. This is because exercising too hard raises blood pressure as well as cortisol and adrenalin levels. This makes you more prone to illness.



So should you exercise if you don’t feel well?  if you have mild symptoms and no fever, light or moderate exercise may help you feel a bit better and actually boost your immune system. Intense exercise will only make things worse and likely put you in bed for a few years.

Symptoms that indicate that you might have been working out too hard include irritability, general heaviness and fatigue.



A fitness trainer can work with you and make sure that you are pacing yourself and working out at a rate that is not going to compromise your body’s ability to recover.