Measuring how exercise affects the immune system is complicated by many variables, including the type and duration of exercise and the age and physical health of a person. While research is not conclusive,
many studies have shown that moderate and high-intensity workouts affect the body's response to illness. In addition, mental health can play an indirect role in physical health.
Immune Response
In order to fight viruses, the human immune system releases antibodies called immunoglobulins when it senses an invading illness, according to Dr. Kursat Karacabey of Firat University. These immunoglobulins can harm the body over time, so a steroid called cortisol is released in the body to counteract the immunoglobulins and suppress the immune system. This natural system keeps your body balanced and wards off illness, and some studies show that the intensity of your workout may affect this balance.
Moderate Exercise
A study of 60 women performed by Karacebey concluded that regular and moderate exercise increases immunoglobulin output in the body, thereby protecting the body from bacteria and viruses. Similarly, a study on mice at the University of Illinois showed the subtly hastened release of T1 cells, an immune system helper cell. While neither of these studies definitively concludes that moderate exercise promotes a healthy immune system, they do suggest that a healthy individual may recover more quickly from an illness with the addition of low-impact aerobic exercise.
High-Intensity Workouts
On the other hand, high-intensity workouts may have a negative effect on the immune system's response. Karacebey's study of immune response to aerobic and anaerobic exercise showed that women practicing anaerobic exercise showed no release of cortisol whereas those exercising aerobically did show an increase in cortisol production. The study performed by the University of Illinois showed T1 cell production in mice to be shut off too soon during prolonged or intense exercise, thereby delaying the immune system's response.
Mental Health
Mental health is indirectly tied to the immune system through exercise. An Ohio State research team speculates that while it is difficult to conclusively measure, long-term stress affects the immune system by disrupting chemical communication among the nervous system, the endocrine system and the immune system. Exercise, meanwhile, fires neurotransmitters that relieve stress and establish normal communication in the body. By exercising regularly, you may be promoting mental and physical health.
References
- Dr. Kursat Karacabey. The Effects of Exercise on the Immune System and Stress Hormones in Sportswomen. 2005.
- Reynolds, Gretchen. The New York Times: Phys Ed: Does Exercise Boost Immunity? 2009.
- Harvard Health Publications: How to Boost Your Immune System. 2010.
- University of Pennsylvania: Office of Health Education: Exercise Can Help Control Stress. 2006.
