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Exercise and the Immune System - Part 2

The first part of this blog looked at what the relationship between immune health and exercise is and what implications it has for those who are training and competing in sports, as well as for the general population. This second part aims to elaborate on measures that can be taken to maintain immune function whether you are a sedentary individual, a coach looking to prevent their athletes from getting infected or an individual undergoing an intense period of training.

The recommendations in this blog post are made incorporating guidelines from various experts in the field of exercise and immune health based on scientific research. While there are various methods that claim to improve or maintain immune function, only those that have good evidence are recommended in this blog. To read further into the mechanisms and details of these recommendations it is suggested to further explore the material given in the references (1-13).

Hygiene practices:

One of the easiest ways to prevent infection is to avoid it through practices of basic hygiene. Recommendations to prevent infection through hygiene practices are:

  • Wash your hands with soap and water regularly and properly (with at least 20-30 seconds of soaping).

  • Avoid touching your face and nose as this a method for self-inoculation with an infection.

  • Avoid contact with people who are infected.

  • During an epidemic practice social distancing, avoid crowds and avoid contact with potentially contaminated or frequently touched surfaces like doorknobs and handles.

  • If you are sick, avoid spreading the illness by staying home and away from people. Especially avoid contact with potentially vulnerable individuals such as the elderly, children, and individuals with medical conditions. If you must go out, wear a mask to reduce the risk of you spreading the infection.

  • If you must sneeze or cough, do so into a disposable tissue or into your elbow, not into your hands.

  • Frequently sanitize surfaces that individuals come in close contact with.

  • Do not share utensils, bottles, glasses etc.

  • Consume only hygienically prepared food and beverages especially those that are not cooked.


Nutrition has found to be one of the simple ways in which one can maintain your immune health. Following these guidelines can help to use nutrition as a tool to maintain it:

  • Ensure sufficient intake of protein, carbohydrates and fats according to your activity level, age, lifestyle and medical conditions. Weight loss diets (especially yo-yo or crash dieting) can compromise your immunity if not carried out correctly.

  • Avoid being deficient in micronutrients such as Vitamin D, Vitamin C, Vitamin E, Zinc, Magnesium, and Iron. These micronutrients are important in keeping various components of the immune system functioning optimally. If you are deficient get treated by a qualified person.

  • Include Probiotic rich food such as Yogurt and Kefir in your diet as these have evidence in maintaining immune health. There are also options to supplement for the same with probiotic supplements containing Lactobacillus and/or Bifidobacterium.

  • Eat a variety of fresh fruits and vegetables. Many plants contain polyphenols and flavonoids like quercetin which are shown to reduce the risk of getting sick.

  • Stay well hydrated, especially when it is hot, humid and you are exercising.

  • Ensure the food you eat is hygienically prepared. Raw food like salads must be thoroughly washed or peeled before eating.


Lifestyle related factors such as sleep, stress and exercise are all important factors in ensuring immune function is maintained. The following are lifestyle related guidelines:

  • If you are sedentary, participating in regular exercise can help to improve the robustness of your immune system.

  • If you are sedentary, participating in regular exercise can help to improve the robustness of your immune system.

  • Stress, both life stress and psychological can lower immune function. If limiting these stressors is not an option manging stress via methods such as meditation, breathwork and counselling can help to maintain immunity.

  • Avoid excessive alcohol intake and smoking, as it is associated with lowered immune function.

  • Avoid excessive alcohol intake and smoking, as it is associated with lowered immune function.

  • Avoid excessive alcohol intake and smoking, as it is associated with lowered immune function.

  • If you have an option to be vaccinated safely for a disease and are at potential risk for the same or are traveling to an area that has a high risk of the disease, then vaccination in advance can be a good disease prevention option. Contact your general physician to get more information about vaccination.

(Adapted from Walsh 2018)

The above figure enumerated the various factors involved in lowering the immunity of an athlete. Below are given some strategies to reduce compromising the health of the immune system and the risk of infection keeping in mind the requirements for training that athletes have:

  • If you plan to train more than 90 minutes. Carbohydrate supplementation (about 30-40 g/ hour of exercise) before, during and post has shown to help to reduce the lowering of immunity as a result of prolonged intense exercise.

  • Sudden increases in training volume and/or load can compromise the immune system. Employing a gradual, periodized increase in training load and adding variety in training can help reduce this risk. Keeping increases in training load to 5-10% per week in situations where an athlete is potentially at risk of infection can help to maintain immunity.

  • Elite athletes need to take part in stressful training to improve performance. If the training factors of recovery, exercise capacity, non-training stress factors, and stress tolerance are well monitored then an athlete can train safely at high volume without compromising immune health too much. An unplanned imbalance between training load and recovery can lead to an over-trained and immunocompromised athlete.

  1. Alternating high and low/moderate training load days can help to modulate this.

  2. Planned recovery days with both active and passive recovery modalities are another strategy to help to balance out the rigours of high training load days/weeks.

  3. Having one complete rest day in a week could help to allow an athlete to recover from training especially during periods of high stress such as during competition season.

  4. Planning deload or recovery weeks post a high stimulus of training load can help the athlete to adapt to exercise training as well as allow their immune system function to recover.

  5. Replacing overly long training sessions with more frequent ‘spike’ (high intensity, shorter duration) sessions is another strategy to prevent reducing immunity.

  • Coaches, medical staff, and athletes must look out for symptoms of illness and can modify training accordingly to reduce the severity of infection and prevent its spread. Quickly isolating a team member with infection symptoms is a good strategy to limit the spread of infection, especially in a team situation.

  • Athletes undergoing the stress of travel can use strategies to readjust their biological clock to prevent any detrimental effects on the immune system.

  • While exercising in extreme conditions- in the heat, humidity, high altitude, athletes are more at risk of infection due to the added stress on the body. Strategies related to training, nutrition and recovery can be devised to reduce this risk. Exercising in cold conditions does not seem to be as much at risk unless the athlete is undergoing conditions of hypothermia. Short exposure to environmental extremes like 30 sec hot to cold showers may enhance immune function.

  • Protecting airways from being directly exposed to very cold and dry air during strenuous exercise, by using a face mask, can help to reduce the risk of an athlete getting an infection.


  1. Walsh, N. P., Gleeson, M., Pyne, D. B., Nieman, D. C., Dhabhar, F. S., Shephard, R. J., & Kajeniene, A. (2011). Position statement part two: maintaining immune health.

  2. Bishop, N. C., Blannin, A. K., Walsh, N. P., Robson, P. J., & Gleeson, M. (1999). Nutritional aspects of immunosuppression in athletes. Sports Medicine, 28(3), 151-176.

  3. Maughan, R. J., Burke, L. M., Dvorak, J., Larson-Meyer, D. E., Peeling, P., Phillips, S. M., & Meeusen, R. (2018). IOC consensus statement: dietary supplements and the high-performance athlete. International journal of sport nutrition and exercise metabolism, 28(2), 104-125.

  4. Bermon, S., Castell, L. M., Calder, P. C., Bishop, N. C., Blomstrand, E., Mooren, F. C., & Nieman, D. C. (2017). Consensus statement immunonutrition and exercise. Exercise immunology review, 23, 8-50.

  5. Gleeson, M., & Walsh, N. P. (2012). The BASES expert statement on exercise, immunity, and infection. Journal of sports sciences, 30(3), 321-324.

  6. Nieman, D. C. (1997). Exercise immunology: practical applications. International Journal of Sports Medicine, 18(S 1), S91-S100.

  7. Walsh, N. P. (2019). Nutrition and athlete immune health: new perspectives on an old paradigm. Sports Medicine, 1-16.

  8. Walsh, N. P. (2018). Recommendations to maintain immune health in athletes. European journal of sport science, 18(6), 820-831.

  9. World Health Organisation. (2020, April 12). Infection Prevention and Control. Retrieved from

  10. Centres for Disease Control and Prevention. (2020, April 2020). Infection Control in Health Care Facilities. U.S. Department of Health & Human Services. Retrieved from

  11. Hull, J. H., Loosemore, M., & Schwellnus, M. (2020). Respiratory health in athletes: facing the COVID-19 challenge. The Lancet Respiratory Medicine.

  12. Schwellnus, M., Soligard, T., Alonso, J. M., Bahr, R., Clarsen, B., Dijkstra, H. P., & Van Rensburg, C. J. (2016). How much is too much?(Part 2) International Olympic Committee consensus statement on load in sport and risk of illness. Br J Sports Med, 50(17), 1043-1052.

  13. Nieman, D. C., & Wentz, L. M. (2019). The compelling link between physical activity and the body's defense system. Journal of sport and health science, 8(3), 201-217.

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