Many people who exercise regularly say it makes them healthier, they are sick less often and generally feel better. On the other hand, according to Emory University, after intense exercise people are more likely to catch a cold. So does exercise help your immune system, or doesn't it?
Expert Insight
Regular moderate exercise increases the number of immunoglobulines circulating in your body, according to a 2005 article in Neuroendocrinology Letters. The authors of the article studied the effect of exercise on the immune system of women who regularly exercise and a comparable group of women who were inactive. Those who exercised had more of the immunoglobulins IgA, IgM and IgG, important antibodies in the fight against disease on a cellular level.
Exercise and Cancer
Regular exercise in cancer survivors has been shown to increase the immune system's ability to kill cancer cells, according to the University of Medicine and Dentistry of New Jersey. Regular moderate exercise increases the activity of natural killer or NK cells, which are the immune cells that fight cancer. This is especially important because the intense effects of chemotherapy suppress the immune system in cancer patients for a while. Exercise can keep them healthier and help them recover faster from chemotherapy.
The Effect of Intense Exercise
Moderate exercise -- five to 60 minutes of 50 percent to 60 percent maximum effort -- seems to enhance the immune system. Intense exercise -- five to 60 minutes of 70 percent or more of maximum effort -- seems to suppress the immune system. So, for instance, someone who ran a marathon is more likely to develop a cold afterward than someone who trained for the marathon but didn't run it, according to a 2007 article in Clinics in Sports Medicine on exercise and the immune system.
Recommendations
Balance moderate exercise with sufficient time for rest and recovery. Keep a training log and record your level of fatigue as well as your workouts. If you notice your fatigue rising, add more rest. Record your morning resting heart rate. If you notice a progressive increase, you may be exercising too hard. Anticipate other forms of stress in your life, such as work-related stress, and adjust your workout schedule to allow for adequate rest. The key to helping your immune system is regular moderate exercise for life, not extremely intense exercise.
References
- Neuroendocrinology Letters: The Effects of Exercise on the Immune System and Stress Hormones in Sportswomen; K. Karacabey et al.; Aug. 2005
- University of Medicine and Dentistry of New Jersey: Does Exercise Affect Health in Women with Breast Cancer?
- Emory University School of Medicine: Exercise, Aging, and the Immune System
- Clinics in Sports Medicine: Exercise and the Immune System; Brolinson, P.G., Elliott, D.; 2007
