Exercise duration modulates upper and lower respiratory fluid cellularity, antiviral activity, and lung gene...

Area of Science:

• Exercise physiology
• Immunology
• Respiratory medicine

Background:

• Exercise offers health benefits, but its impact on respiratory infections and local immunity remains unclear.
• Limited research exists on prolonged exercise effects on respiratory immunity and antiviral activity.

Purpose of the Study:

• To investigate how exercise duration affects upper and lower respiratory tract immunity.
• To assess changes in nasal lavage fluid (NALF) and bronchoalveolar lavage (BAL) fluid immune cells and gene expression.

Main Methods:

• Human subjects provided NALF at rest and after 45 and 180 minutes of exercise.
• A murine model was used to analyze BAL fluid and lung gene expression after exercise.
• Antiviral activity in NALF was tested against Influenza A.

Main Results:

• 180 minutes of exercise increased NALF total cells and leukocytes, correlating with fatigue.
• 45-90 minutes of exercise decreased BAL total cells and neutrophils in mice.
• Nasal lavage fluid showed significant antiviral activity; lung gene expression indicated cellular stress but not broad inflammation.

Conclusions:

• Exercise duration differentially modulates respiratory tract cellularity and antiviral activity.
• These immune changes may influence susceptibility to respiratory viruses like influenza, rhinovirus, and SARS-CoV-2.