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Pulmonary Diffusing Capacity for Nitric Oxide During Exercise in Morbid Obesity
Author(s) -
Zavorsky Gerald S.,
Kim Do J.,
McGregor Elspeth R.,
Starling Jennifer M.,
Gavard Jeffrey A.
Publication year - 2008
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2008.402
Subject(s) - dlco , pulmonary diffusing capacity , medicine , diffusing capacity , cardiology , vo2 max , anesthesia , heart rate , lung , blood pressure , lung function
Morbidly obese individuals may have altered pulmonary diffusion during exercise. The purpose of this study was to examine pulmonary diffusing capacity for nitric oxide (DLNO) and carbon monoxide (DLCO) during exercise in these subjects. Ten morbidly obese subjects (age = 38 ± 9 years, BMI = 47 ± 7 kg/m 2 , peak oxygen consumption or O 2peak = 2.4 ± 0.4 l/min) and nine nonobese controls (age = 41 ± 9 years, BMI = 23 ± 2 kg/m 2 , O 2peak = 2.6 ± 0.9 l/min) participated in two sessions: the first measured resting O 2 and O 2peak for determination of wattage equating to 40, 75, and 90% oxygen uptake reserve (O 2 R). The second session measured pulmonary diffusion from single‐breath maneuvers of 5 s each, as well as heart rate (HR) and O 2 over three workloads. DLNO, DLCO, and pulmonary capillary blood volume were larger in obese compared to nonobese groups ( P ≤ 0.06) only when expressed relative to alveolar volume (VA). The slope between O 2 and all measures of pulmonary diffusion, whether or not expressed to VA, were not different between groups ( P > 0.10). The morbidly obese have increased pulmonary diffusion per unit increase in VA compared with nonobese controls which may be due to a lower rise in VA per unit increase in O 2 in the obese during exercise.