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Canadian Respiratory Journal
Volume 20, Issue 1, Pages e1-e4
Original Article

The effect of inhaled menthol on upper airway resistance in humans: A randomized controlled crossover study

Effie J Pereira, Lauren Sim, Helen S Driver, Chris M Parker, and Michael F Fitzpatrick

Sleep Disorders Laboratory, Kingston General Hospital and Department of Medicine, Queen’s University, Kingston, Ontario, Canada

Copyright © 2013 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


BACKGROUND: Menthol (l-menthol) is a naturally-occurring cold receptor agonist commonly used to provide symptomatic relief for upper airway congestion. Menthol can also reduce the sensation of dyspnea. It is unclear whether the physiological action of menthol in dyspnea reduction is through its cold receptor agonist effect or whether associated mechanical changes occur in the upper airway.

OBJECTIVE: To determine whether menthol inhalation alters upper airway resistance in humans.

METHODS: A randomized, sham-controlled, single-blinded crossover study of inhaled menthol on upper airway resistance during semirecumbent quiet breathing in healthy subjects was conducted. Ten healthy participants (eight female) with a mean (± SD) age of 21±1.6 years completed the study.

RESULTS: Nasal resistance before testing was similar on both occasions. No differences were found in respiratory frequency (mean ± SEM) (menthol 17.0±1.1 cmH2O/L/s; sham 16.9±0.9 cmH2O/L/s), minute ventilation (menthol 7.7±0.5 cmH2O/L/s; sham 7.9±0.5 cmH2O/L/s) or total inspiratory time/total breath time (menthol 0.4±0.1 cmH2O/L/s; sham 0.4±0.1 cmH2O/L/s). The upper airway resistance was similar during menthol (3.47±0.32 cmH2O/L/s) and sham (3.27±0.28 cmH2O/L/s) (P=0.33) inhalation.

CONCLUSION: Inhalation of menthol does not alter upper airway resistance in awake human subjects.