Exhaled nitric oxide is associated with acute mountain sickness susceptibility during exposure to normobaric hypoxia.
Nitric oxide is a gaseous signaling molecule that participates in a large variety of physiological functions and may have a role in the pathology of altitude illnesses, such as acute mountain sickness (AMS). The effect of normobaric hypoxia on the fraction of exhaled NO ( [Formula: see text] ) is a controversial area of high altitude physiology, with the effect varying widely across studies. We exposed 19 male subjects to normobaric hypoxia for 6h and measured  [Formula: see text]  and AMS (via Lake Louise Score) each hour. For data analysis, subjects were divided into AMS-positive and AMS-negative groups based on their Lake Louise Scores during exposure. Eighteen subjects completed the study, and the incidence of AMS was 50%. Mean  [Formula: see text]  was unchanged at hour 1 but was significantly elevated above baseline for the remainder of the normobaric hypoxia exposure (p<0.001). Subjects who developed AMS had a significantly lower mean  [Formula: see text]  at baseline compared to resistant subjects (p=0.013). Further investigations are warranted to confirm our results and to understand the physiological basis of this association.
School of Kinesiology, University of British Columbia, 6081 University Boulevard, Vancouver, BC, Canada V6T 1Z1. mmacinni@interchange.ubc.ca
M J
MJ
Macinnis
E A
EA
Carter
M S
MS
Koehle
J L
JL
Rupert
D000532:Altitude Sickness / Q000209:etiology / Q000378:metabolism*; D004198:Disease Susceptibility / Q000378:metabolism; D045853:Exhalation; D006801:Humans; D000860:Hypoxia / Q000150:complications* / Q000378:metabolism; D008297:Male; D009569:Nitric Oxide / Q000032:analysis* / Q000378:metabolism*
D009569:Nitric Oxide