Can the immunological system of the upper respiratory tract, improved by physical exercise, act as a first immunological barrier against SARS-CoV-2?

According to the biomedical literature reviewed, physical exercise can decrease or improve the level of IgA concentrations. However, it is important to take into account factors such as training load, recovery during the exercise session and between training, as well as the exercise modality. Furthermore, the characteristics of the target population should be taken into account to maximize the adaptive immune response to adequately strengthen the upper respiratory tract and potentially be a barrier against SARS-CoV-2 infection.