One of the great benefits of regular exercise is the boost it provides to the immune system.  Regular exercise protects against sickness for all people, but particularly in older aged people and those with chronic diseases (1).  This is shown to be the case with large population studies for both communicable diseases, such as bacterial and viral infections, and noncommunicable diseases such as cancer and diabetes.  

Regular physical activity and structured moderate to strenuous exercise typically enhance the body’s immune regulation by increasing antibodies and white blood cells that help fight disease, and clear potentially harmful bacteria from airways and lungs.  

Furthermore, research suggests that regular exercise may delay aging of the immune system that typically degrades in old age (2). This is welcome news! While we cannot control growing older, we can control our exercise habits.   


Does an Intense Exercise Session Decrease Immunity? 


One question that has generated a lot of debate in the scientific community is: “Does a single intense and strenuous bout of exercise predispose you to disease and infection?” Recent research debunks the myth that that immune function is suppressed immediately after strenuous exercise (1). In fact, there is good evidence that a single bout of exercise will enhance your immune system regulation possibly by deploying the immune cells throughout the body. The immune cells conduct an immune ‘surveillance’  on the surface of the organs (e.g. nose, throat, lungs, digestive tract), where bacteria and viruses frequently lodge. 

There is one caveat.  Elite athletes — particularly endurance athletes who compete in long distance events — have shown higher rates of upper respiratory infection after strenuous races (3).   There is no definitive theory that supports this response to exercise, although it could be due to non-exercise factors such as exposure to large numbers of people on race day, travel, sleep disruption, and altered nutrition. This unknown should not skew the large body of evidence that exercise, even strenuous exercise, can enhance your immune system particularly with aging, and protect you against developing a range of diseases.  

Consider building your immune system by starting or increasing your exercise regime. The benefits of exercise are enormous. If you haven’t done so already, sign up for our six secrets to initiate and sustain an exercise habit.  




  1. Campbell, J. P. and J. E. Turner (2018). “Debunking the Myth of Exercise-Induced Immune Suppression: Redefining the Impact of Exercise on Immunological Health Across the Lifespan.” Front Immunol 9: 648. 
  2. Campbell, J. P. and J. E. Turner (2019). “There is limited existing evidence to support the common assumption that strenuous endurance exercise bouts impair immune competency.” Expert Rev Clin Immunol 15(2): 105-109. 
  3. Walsh, N. P. (2018). “Recommendations to maintain immune health in athletes.” Eur J Sport Sci 18(6): 820-831.