Dr. Sara Forsyth
Sport & Exercise Medicine
We know you don’t actually “catch a cold” from being cold but it is well established that one is more susceptible to illness during times of supressed immunity. Evidence suggests that periods of heavy intense training can result in suppressed immune cell function and that episodes of upper respiratory infections (URTI) seem to increase around intense training blocks and competition. Immunity is thought to decrease transiently in the hours after exertion. Prolonged heavy training sessions in particular have been shown to decrease immune function.
Athletes often face other challenges to immunity including life stress, sleep disruption, environmental extremes and unintentional nutritional deficits. These factors influence immune function via activation of the hypothalamic–pituitary–adrenal axis and the sympathetic nervous system resulting disruption of many immunoregulatory hormones.
Strategies to mitigate the impacts on the immune response would result in less missed training and competition due to illness. All the basic measures are paramount in preventing illness. These are the things you have heard before like good hygiene and getting adequate sleep. Basic hygiene strategies include frequent handwashing, especially before eating and avoiding touching your face. The nose and mouth are major portals of entry for germs. Getting lots of fresh air and avoiding crowded spaces during the flu season can be beneficial. Sleep needs increase during training and times of stress. As you work hard in your lead up to a race, making sleep a priority, as you would make training a priority, is a recipe for success. Studies show that chronic disruption of sleep increases risk of illness.
There is also a body of evidence addressing the role of nutrition and supplementation in prevention of illness. Ensuring you are meeting your macronutrient (protein fat and carbohydrate) needs has been shown, to not only help prevent injury, but also helps prevent upper respiratory illness. A post workout snack within 30 minutes will assist with repletion of macronutrients. This snack should include adequate carbohydrate and protein. There is some evidence for Vitamin D, C and probiotic supplementation in the prevention of URTI. Zinc lozenges may play a role in shortening the course of an URTI, if started very early on. There does not appear to be any strong evidence for high doses of Vitamin C in diminishing symptoms during an URTI.
It has been well established that intense training impacts the immune system through a variety of pathways. This results in an athlete’s increased susceptibility to various illnesses during key training and racing periods. Various strategies, from self-care, nutrition and supplementation to training plan modification have shown promise in mitigating the impact of physical and psychological stressors on the immune system.
