Upper Respiratory Tract Infections in Sport and the Immune System Response. A Review

SIMPLE SUMMARY: This review aims at clarifying the relationships of heavy training with the upper respiratory tract infections (URTI), a topic which has reach the public awareness with the recent outbreaks of Covid 19. The URTIs are quite common in several sport activities among athletes who undergo heavy training. Causes of URTI are still poorly understood, because can be related with innate and genetic susceptibility and with several environmental factors connected with training load and nutrition. The time course of the inflammation process affecting URTI after training, has been also reviewed. After a survey of the possible physiological and psychological causes (stressors), including a survey of the main markers of inflammation currently found in scientific literature (mainly catecholamines), we provided evidence of the ingestion of carbohydrates, C, D, and E vitamins, probiotics and even certain fat, in reducing URTI in athletes. Possible countermeasures to URTI can be a correct nutrition, sleep hygiene, a proper organization of training loads, and the use of technique to reduce stress in professional athletes. There is a lack of studies investigating social factors (isolation) albeit with Covid 19 this gap has been partially fill. The results can be useful also for non-athletes. ABSTRACT: Immunity is the consequence of a complex interaction between organs and the environment. It is mediated the interaction of several genes, receptors, molecules, hormones, cytokines, antibodies, antigens, and inflammatory mediators which in turn relate and influence the psychological health. The immune system response of heavily trained athletes resembles an even more complex conditions being theorized to follow a J or S shape dynamics at times. High training loads modify the immune response elevating the biological markers of immunity and the body susceptibility to infections. Heavy training and/or training in a cold environment increase the athletes’ risk to develop Upper Respiratory Tract Infections (URTIs). Therefore, athletes, who are considered healthier than the normal population, are in fact more prone to infections of the respiratory tract, due to lowering of the immune system in the time frames subsequent heavy training sessions. In this revision we will review the behavioral intervention, including nutritional approaches, useful to minimize the “open window” effect on infection and how to cope with stressors and boost the immune system in athletes.