Current return to sports recommendations after non-severe COVID-19 from an exercise immunology perspective: A scoping review

Acute respiratory tract infections (ARTI) caused by SARS-CoV-2 continue to be a cause for medical consultations and absence from training among athletes. Over the past years, these infections have been associated with more severe symptoms and multi-systemic complications, as well as longer time needed to return to sports than common ARTI. Updated guidelines from medical societies advise to resume athletic activities not until full clinical recovery has been reached. Beyond that, graduated protocols for the return to sport propose a stepwise load progression once athletes have been medically cleared. However, few guidelines provide insight into the rationale behind specific recommendations and leave it unclear to what extent they included immunological considerations. In this review, we give an overview of existing return to sports recommendations and offer a contextualization from an exercise immunology perspective. Herein, physiological windows of acute infection regulation play an important role that may need to be considered by sports and exercise professionals. That includes the consideration of acute effector responses that resolve around day ten post-symptom onset. Additionally, at least three successive symptom-free days should have passed before athletes resume sports.