Exercise-induced dehydration alters pulmonary function but does not modify airway responsiveness to dry air in athletes with mild asthma

Simpson, A. J.; Romer, L. M.; Kippelen, P.

Abstract

Local airway water loss is the main physiological trigger for exercise-induced bronchoconstriction (EIB). Our aim was to investigate the effects of whole body water loss on airway responsiveness and pulmonary function in athletes with mild asthma and/or EIB. Ten recreational athletes with a medical diagnosis of mild asthma and/or EIB completed a randomized, crossover study. Pulmonary function tests, including spirometry, whole body plethysmography, and diffusing capacity of the lung for carbon monoxide (DlCO), were conducted before and after three conditions: 1) 2 h of exercise in the heat with no fluid intake (dehydration), 2) 2 h of exercise with ad libitum fluid intake (control), and 3) a time-matched rest period (rest). Airway responsiveness was assessed 2 h postexercise/rest via eucapnic voluntary hyperpnea (EVH) to dry air. Exercise in the heat with no fluid intake induced a state of mild dehydration, with a body mass loss of 2.3 ± 0.8% (SD). After EVH, airway narrowing was not different between conditions: median (interquartile range) maximum fall in forced expiratory volume in 1 s was 13 (7–15)%, 11 (9–24)%, and 12 (7–20)% in dehydration, control, and rest conditions, respectively. Dehydration caused a significant reduction in forced vital capacity (300 ± 190 ml, P = 0.001) and concomitant increases in residual volume (260 ± 180 ml, P = 0.001) and functional residual capacity (260 ± 250 ml, P = 0.011), with no change in DlCO. Mild exercise-induced dehydration does not exaggerate airway responsiveness to dry air in athletes with mild asthma/EIB but may affect small airway function.

Citation

Simpson, A. J., Romer, L. M., & Kippelen, P. (2017). Exercise-induced dehydration alters pulmonary function but does not modify airway responsiveness to dry air in athletes with mild asthma. Journal of Applied Physiology, 122(5), 1329-1335. https://doi.org/10.1152/japplphysiol.01114.2016

• Journal Article Type: Article
• Acceptance Date: Mar 8, 2017
• Online Publication Date: May 18, 2017
• Publication Date: May 1, 2017
• Deposit Date: Nov 23, 2017
• Publicly Available Date: Nov 29, 2017
• Journal: Journal of Applied Physiology
• Print ISSN: 8750-7587
• Publisher: American Physiological Society
• Peer Reviewed: Peer Reviewed
• Volume: 122
• Issue: 5
• Pages: 1329-1335
• DOI: https://doi.org/10.1152/japplphysiol.01114.2016
• Keywords: Airway hyperresponsiveness; Eucapnic voluntary hyperpnea; Exercise-induced bronchoconstriction; Exercise-induced asthma; Whole body dehydration
• Public URL: https://hull-repository.worktribe.com/output/424456
• Publisher URL: http://jap.physiology.org/content/122/5/1329
• Contract Date: Nov 29, 2017