You are right in the middle of a gym program, which is going great, and you haven’t missed a day yet. Then all of a sudden you get struck down with a cold or flu and you are left with the common debate. Whether you push through it and ‘sweat it out’ or rest up and let your body recover. So what is the best option?
The key to answering this question, researchers are suggesting, is that it depends on the type of activity you want to do and the severity of your symptoms. Exercise awakens a stress response in the body that differs by the intensity of the workout – meaning high intensity exercise elicits more stress then low intensity. When you are fit and healthy your body can easily adapt to this stress however when you are sick, a high intensity workout can be more then your body can handle- potentially doing more harm then good.
So the first thing to address in your decision is your symptoms. If your symptoms are quite mild and above the neck- such as runny nose, sneezing and a cough, studies have suggested that you may be fine to continue your workout routine. However if the symptoms are more severe and are ‘below the neck’ or systemic such as body aches, stomach pains, nausea and fever then you may be prolonging your sickness by hitting the gym (2).
The intensity that you exercise at is also important. Results of a recent study suggest that moderate or low intensity training during an upper respiratory infection does not alter the severity and duration of the illness (3). Whereas another study found that intense exercise during illness, can cause immunosuppression and increase the severity of a respiratory viral infection (2). Low intensity exercise such as qigong, tai-chi, yoga or walking can actually improve cell mediated immunity and anti-body response in the immune system- potentially improving the severity and duration of respiratory illnesses (4). One study in particular looked at the parameters of immunity such as lymphocytes, immunoglobulins, natural-killer cells and myeloid dendritic cells and overall found favourable effects of these low intensity types of exercise (5).
Therefore it becomes apparent there is good evidence to suggest that moderate or low intensity exercise can improve the immune response to respiratory viral infection by limiting an excessive TH1 immune reaction to pathogens. Whereas intense exercise could actually allow the virus to gain a better foothold and increase the severity of symptoms (2). So when you are sick, depending on your symptoms, taking a step back and focusing on your lower intensity exercises such as yoga or walking can do wonders instead of trying to power through a full intensity strength session.
1. Nieman, D. C., Henson, D. A., Austin, M. D., & Sha, W. (2011). Upper respiratory tract infection is reduced in physically fit and active adults. British Journal of Sports Medicine, 45(12), 987-992. doi: 10.1136/bjsm.2010.077875
2. Martin, S. A., Pence, B. D., & Woods, J. A. (2009). Exercise and Respiratory Tract Viral Infections. Exercise and sport sciences reviews, 37(4), 157-164. doi: 10.1097/JES.0b013e3181b7b57b
3. Weidner, T. G., Cranston, T., Schurr, T., & Kaminsky, L. A. (1998). The effect of exercise training on the severity and duration of a viral upper respiratory illness. Med Sci Sports Exerc, 30(11), 1578-1583.
4. Wang, C. W., Ng, S. M., Ho, R. T., Ziea, E. T., Wong, V. C., & Chan, C. L. (2012). The effect of qigong exercise on immunity and infections: a systematic review of controlled trials. Am J Chin Med, 40(6), 1143-1156. doi: 10.1142/s0192415x1250084x
5. Ho, R. T., Wang, C. W., Ng, S. M., Ho, A. H., Ziea, E. T., Wong, V. T., & Chan, C. L. (2013). The effect of t'ai chi exercise on immunity and infections: a systematic review of controlled trials. J Altern Complement Med, 19(5), 389-396. doi: 10.1089/acm.2011.0593