Dyspnea from exercise in cold air is not always asthma

Area of Science:

• Respiratory Medicine
• Exercise Physiology

Background:

• Exercise-induced dyspnea is often misdiagnosed as asthma.
• Lack of bronchoconstriction in some patients necessitates alternative explanations.

Purpose of the Study:

• Investigate exercise in cold air's effect on patients with exercise-induced dyspnea.
• Assess changes in symptoms, physiological parameters, and capsaicin cough sensitivity.

Main Methods:

• Eleven patients with exercise-induced dyspnea (no asthma) and 11 controls underwent capsaicin challenge twice.
• One challenge was preceded by exercise in a cold chamber.
• Measured coughs, airway symptoms, spirometry, respiratory rate, pulse, end-tidal CO2, and PSaO2.

Main Results:

• Patients reported more coughs and airway symptoms during exercise than controls.
• Post-exercise, spirometry was unchanged, but capsaicin cough sensitivity increased, and end-tidal CO2 decreased in patients.
• These changes were significant compared to controls and pre-exercise values.

Conclusions:

• Exercise-induced dyspnea without bronchoconstriction may involve hypocapnia due to hyperventilation.
• Increased capsaicin cough sensitivity is associated with this condition.
• Exercise-induced asthma diagnosis requires careful consideration, especially when bronchoconstriction signs are absent.