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

ABSTRACT

Introduction

The main route of transmission of SARS-CoV-2 is the upper respiratory tract via cell membranes, including angiotensin-converting enzyme 2 (ACE2) and transmembrane host-associated serine protease transmembrane serine protease 2 (TMPRSS2). Both enzymes present in the nasal epithelium are the first direct point of contact for SARS-CoV-2. In this sense, the mucosal immune mechanisms of the upper respiratory tract, including immunoglobulin A (IgA), could be enhanced by physical exercise and be the first defense mechanism against the transmission and infection of SARS-CoV-2.

Areas covered

The authors reviewed recent biomedical literature available in databases related to the effects of exercise and training modalities on IgA concentration levels in the upper respiratory tract in different populations.

Expert opinion

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.

KEYWORDS:

• Physical exercise
• Immunity
• SARS-COV-2
• COVID-19

Article highlights

• The SARS-CoV-2 virus is transmitted through the upper respiratory tract by cell membranes that contain ACE2 and TMPRSS2 enzymes, also present in type II alveolar epithelial cells of the lower respiratory tract.

• ACE2 receptors expressed in the upper respiratory tract, and high viral loads in swabs from both symptomatic and asymptomatic patients, may mean that there is also a possibility that the targets of initial SARS-CoV-2 infection are also centered in the upper respiratory tract.

• Immunological mechanisms in the mucosa of the upper respiratory tract, such as secretory immunoglobulin A (IgA), may be the first defense mechanism against SARS-CoV-2 transmission and infection.

• Properly prescribed physical exercise could positively modulate IgA concentration levels and strengthen the immune mechanism of the upper respiratory tract and potentially be a barrier against SARS-CoV-2 infection.

Author contributions

All authors substantially contributed to the conception and design of the review article, interpreted the relevant literature, and participated in writing the review article or revised it for intellectual content.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded The authors have no funding to report.