The researchers tested 30 adult non-smokers with no history of asthma or respiratory diseases, and used cough tests to determine how e-cigarettes affect the cough reflex. Each study subject inhaled 30 puffs of an electronic cigarette, which contained nicotine in a vehicle of distilled water. After 15 minutes of the e-cigarette 'vaping' session, the subjects were tested again, using the Capsaicin cough challenge and then tested again after 24 hours.
The results showed a significant decrease in cough reflex sensitivity among the subjects, as compared with their baseline levels. The authors observed that nicotine was probably responsible for the effect on the cough reflex and suggested that nicotine had an immediate stimulation of the cough reflex and a delayed inhibition.
The study is published in Journal Chest.