Reduced hyperpnea-induced bronchospasm following repeated cold air challenge

Area of Science:

• Pulmonary Medicine
• Environmental Physiology

Background:

• Asthma is often triggered by cold air exposure and exercise, leading to bronchospasm.
• Understanding airway responses to cold air is crucial for managing asthma symptoms.

Purpose of the Study:

• To assess the effects of a 12-week cold air hyperpnea training protocol on expiratory function in asthmatic subjects.
• To determine if repeated cold air challenges can reduce exercise-induced bronchospasm.

Main Methods:

• 12 asthmatic subjects underwent 36 sessions of isocapnic cold air hyperpnea over 12 weeks.
• Expiratory function was measured before and after cold air provocation and exercise, both pre- and post-training.

Main Results:

• Pre-training, both cold air provocation and exercise significantly reduced expiratory function.
• Post-training, the reduction in expiratory function after cold air provocation and exercise was significantly less pronounced.
• A subset of subjects experienced reduced baseline pulmonary function and exacerbated asthma symptoms during training.

Conclusions:

• Repeated cold air challenges can lead to airway acclimatization, reducing exercise-induced bronchospasm in asthma.
• Potential mechanisms include airway habituation or vasodilation.
• An unanticipated finding suggests that cold air training may induce long-term airway inflammation and worsen asthma symptoms in some individuals.