It’s vital to avoid illness after Summer ends, as there’s nothing worse then getting sick when you want to train hard. And it’s this time of year is when athletes are susceptible to getting these Winter nasty’s; upper respiratory infections (URTI’s) and viral infections which are particularly problematic during damp cold mornings and when exercise intensity is high. i.e. CrossFit!
Although exercise is a powerful tool to reduce the likelihood of infection, the severity can also increase URTI incidence (4), especially post WOD when you’re at your most immunosuppressive.
But why? Why are athletes more susceptible?
- Increased exposure to pathogens – Heavy breathing, wounds (hands!) and big group of people can all play a part in higher rates of infection.
- Increased stress – Yes I know CrossFit is fun, but it’s also physically stressful. Environmental stress, poor sleep and inadequate diet also play a role in increasing stress levels.
- Under nutrition – The biggy is not eating enough and can easily lead to immunodepression and the risk of URTI’s.
But how can nutrition help to avoid illness?
- Carbohydrate intake – Plasma glucose helps reduce stress hormones like cortisol, which can inhibit immune function (3). Athletes must be especially aware when training under low glycogen conditions. More reasons not to fear carbs!
- Protein – A deficiency in protein can affect replication of proteins that help immune defence (Igs, cytokines). So ensure you have adequate protein throughout the day (2g.kg.day) and look to consume complete proteins where possible.
- Fish oil and omega 3 – Omega 3 has been shown to have anti-inflammatory properties, although more is not necessarily better (8). So eat your oily fish 🙂
- Micronutrient deficiencies – Even though increased exercise can require additional support (iron, zinc, magnesium), try and be aware of RDA’s. More is not always better so still read the label!
- Vitamin D – There’s good evidence to show how vitamin D can help with respiratory infections (7). During winter months when Vit D is chronically low (especially in the UK!), supplementation is important to help reach adequate amounts. There’s also a relationship with adequate vitamin D and saliva IgA, which is the first line of defence against infection.
- Fluid – Dehydration can lead to stress hormone secretion (cortisol) inducing potential infection. Saliva flow rate also maintains Iga, so drink water even if you’re not thirsty.
- Probiotics may reduce URTI’s, however, the athlete must consider the strain, quantity, quality and storage. More is not necessarily better (1).
Anything else you should be doing to help reduce the chances of infection?
- Minimise hand to mouth contact and improve hygiene Wash your hands!
- Medical support – immunisation
- Avoid rapid weight loss
- Reduce stress and look to improve sleep
- Stop or reduce training when you’re feeling run down, be smart about your recovery
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- Cox, A., Pyne, D., Saunders, P. and Fricker, P. (2008). Oral administration of the probiotic Lactobacillus fermentum VRI-003 and mucosal immunity in endurance athletes. British Journal of Sports Medicine, 44(4), pp.222-226.
- Gleeson, M. (2006). Can Nutrition Limit Exercise-Induced Immunodepression?. Nutrition Reviews, 64(3), pp.119-131.
- Gunzer, W., Konrad, M. and Pail, E. (2012). Exercise-Induced Immunodepression in Endurance Athletes and Nutritional Intervention with Carbohydrate, Protein and Fat — What Is Possible, What Is Not?. Nutrients, 4(12), pp.1187-1212.
- Nieman, D. (1997). Risk of Upper Respiratory Tract Infection in Athletes: An Epidemiologic and Immunologic Perspective. Journal of athletic training, 34(2), pp.344-349.
- Pedersen, B. (2000). Effects of exercise on lymphocytes and cytokines. British Journal of Sports Medicine, 34(4), pp.246-251.
- Peters, E. and Bateman, E. (1983). Ultramarathon running and upper respiratory tract infections. An epidemiological survey. South African medical journal, 64(15).
- Von Essen, M., Kongsbak, M., Schjerling, P., Olgaard, K., Ødum, N. and Geisler, C. (2010). Vitamin D controls T cell antigen receptor signaling and activation of human T cells. Nature Immunology, 11(4), pp.344-349.
- Yan, Y., Jiang, W., Spinetti, T., Tardivel, A., Castillo, R., Bourquin, C., Guarda, G., Tian, Z., Tschopp, J. and Zhou, R. (2013). Omega-3 Fatty Acids Prevent Inflammation and Metabolic Disorder through Inhibition of NLRP3 Inflammasome Activation. Immunity, 38(6), pp.1154-1163.