title: The Influence of 17 Hours of Normobaric Hypoxia on Parallel Adjustments in Exhaled Nitric Oxide and Airway Function in Lowland Healthy Adults.
abstract: Van Iterson, Erik H., Eric M. Snyder, and Bruce D. Johnson. The influence of 17 hours of normobaric hypoxia on parallel adjustments in exhaled nitric oxide and airway function in lowland healthy adults. High Alt Med Biol. 18:1-10, 2017.-Currently, there is a disparate understanding of the role that normobaric hypoxia plays in affecting nitric oxide (NO) measured in exhaled air (eNO) and airway function in lowland healthy adults. Compared to normobaric normoxia, this study aimed to test the effect of 17 hours of normobaric hypoxia on relationships between eNO and airway function in healthy adults. In a crossover study including 2 separate visits, 26 lowland healthy Caucasian adults performed eNO and pulmonary function tests on visit 1 in normobaric normoxia, while repeating all tests on visit 2 following 17 hours of normobaric hypoxia (12.5% O2). Compared to normobaric normoxia, eNO (29 ± 24 vs. 36 ± 28 ppb), forced expiratory volume in one second (FEV1) (4.1 ± 0.7 vs. 4.3 ± 0.8 L), mean forced expiratory flow between 25% and 75% FVC (FEF25-75) (3.9 ± 1.0 vs. 4.2 ± 1.2 L/s), and forced expiratory flow at 75% FVC (FEF75) (2.0 ± 0.7 vs. 2.3 ± 0.8 L/s) increased in normobaric hypoxia, respectively (all p < 0.05). Correlations at normoxia between eNO and FEV1(r = 0.39 vs. 0.44), FEF25-75(r = 0.51 vs. 0.51), and FEF75(r = 0.53 vs. 0.55) persisted as both parameters increased in hypoxia, respectively. For the first time, these data suggest that 17 hours of hypoxic breathing in the absence of low ambient pressure contribute to increased eNO and airway function in lowland healthy adults.
authors.affiliation: 1 Department of Cardiovascular Diseases, Mayo Clinic College of Medicine , Rochester, Minnesota.
authors.forename: Erik H
authors.initials: EH
authors.lastname: Van Iterson
authors.affiliation: 2 Department of Kinesiology, University of Minnesota , Minneapolis, Minnesota.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Snyder
authors.affiliation: 1 Department of Cardiovascular Diseases, Mayo Clinic College of Medicine , Rochester, Minnesota.
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Johnson
mesh_terms: D000328:Adult; D000531:Altitude; D001944:Breath Tests; D018592:Cross-Over Studies; D045853:Exhalation / Q000502:physiology*; D005260:Female; D005540:Forced Expiratory Flow Rates; D005541:Forced Expiratory Volume; D064368:Healthy Volunteers; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D012129:Respiratory Function Tests; D013997:Time Factors; D055815:Young Adult
chemical_list: D009569:Nitric Oxide
keywords: NO hypoxia; NOS hypoxia; altitude hypoxia; ambient pressure hypoxia; hypobaric hypoxia; pulmonary function hypoxia