Cold air inhalation does not affect the severity of EIB after exercise or eucapnic voluntary hyperventilation

Area of Science:

• Pulmonary Physiology
• Exercise Science
• Respiratory Medicine

Background:

• Exercise-induced bronchoconstriction (EIB) is linked to osmotic and thermal changes from breathing conditioned air during high ventilation.
• Investigating the specific roles of air temperature and humidity in EIB is crucial for understanding its pathophysiology.

Purpose of the Study:

• To assess lung function following exercise and eucapnic voluntary hyperventilation (EVH) under varying temperature and humidity conditions.
• To differentiate the impact of cold air versus dry air on EIB severity.

Main Methods:

• Twenty-two subjects with probable EIB underwent a room-temperature EVH challenge.
• Participants then completed randomized challenges involving cold-temperature EVH, room-temperature exercise, and cold-temperature exercise.
• Spirometry measured forced expiratory volume in 1 second (FEV1) pre- and post-challenge.

Main Results:

• No significant differences in FEV1 decline were observed between room-temperature and cold-temperature challenges for either EVH or exercise.
• Room-temperature EVH showed a trend towards a greater FEV1 fall compared to cold-temperature exercise.
• The primary driver of EIB appears to be air dryness rather than cold temperature.

Conclusions:

• The findings suggest that the dryness of inhaled air is a critical factor in triggering EIB.
• Cold temperature alone does not appear to exacerbate EIB symptoms when air humidity is controlled.
• These results have implications for environmental control and testing protocols for individuals with EIB.