Upper respiratory tract infections and the immune system response. A review.

Abstract

Purpose: the spreading of the COVID-19 epidemic raised a question on why very well trained, healthy, and young athletes have been infected. In this review, the emerging topic in the field of sport immunology has been studied with the aim to provide advice on how strengthening the immune system (IS) and how to help the recover after heavy effort and prevent upper respiratory tract infection (URTI) in athletes. Methods: a literature search was performed on available public scientific databases. Results: URTI, a common illness among heavy trained athletes, happens in the time frame of temporary depression of the IS following heavy training or competition. T cells has been identified as the main factor in the immune response to counteract the cascade mediators of inflammation. Life habits, environmental and psycho-social factors such as sleep loss and life stressors are the major causes of IS depression, and it emerge that there is an optimal training load exposure which reinforce the IS, while too low or too much training being detrimental. Conclusions: immunodepression in heavy trained athletes can be counteracted with a proper distribution of training loads, nutritional interventions, correction of lifestyle habits such as sleep hygiene, thermotherapy, and recovery techniques. Psycho-social interventions also seem to have a positive effect on reducing the post exercise inflammation and in boosting the IS response. Novel bioinformatic approaches can help to understand the IS response in athletes and the management of critical situations.