Regular supplementation with a high quality quercetin supplement may reduce incidence of viral upper respiratory tract infection following periods of intensive exercise.
While regular moderate-intensity exercise is likely to assist in maintaining immune health and preventing infection, prolonged heavy exertion is likely to do the opposite. Some experts refer to the concept of an 'open window' - a period of up to 72 hours following intensive exercise during which individuals remain more susceptible to infections caused by viruses and bacteria. During this window, routine exposures to pathogens may allow for clinical infection to take hold more readily.
Quercetin, a natural antioxidant found in many foods derived from plants, has been shown to exhibit immunomodulatory effects and natural antipathogenic activity which may support the immune system to fight illness. Research has shown that Quercetin supplementation can reduce the incidence of viral upper respiratory tract infection in the immediate post-exercise period following intensive exercise and in individuals suffering from high mental stress, conditions in which it is known that immune function is decreased and the incidence of viral infections is higher.
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2. Nieman D, Henson D, Gross S, Jenkins D, Davis J, Murphy E et al. Quercetin Reduces Illness but Not Immune Perturbations after Intensive Exercise. Medicine & Science in Sports & Exercise [Internet]. 2007;39(9):1561-1569. Available from: https://journals.lww.com/