Exhaled nitric oxide during exercise: site of release and
modulation by ventilation and blood flow.
Phillips, Charles R., George D. Giraud, and William E. Holden.
Medical Service, Portland VA Medical Center, Portland, OR 97201
APStracts 3:0055A, 1996.
To define the site of release and factors modulating exhaled nitric
oxide (NO) during exercise in humans, we measured exhaled NO output
during exercise, during exercise after balloon occlusion of the
nasopharynx (to exclude nasal NO), and at rest with isocapneic
hyperventilation or dobutamine infusion. Exhaled NO output increased
from rest to exercise (57 10 to 171 30 nL/min/M2, p<0.003, n=8).
Excluding nasal NO reduced exhaled NO at rest and during exercise.
Calculated nasal contribution at rest (53 5%) decreased during
exercise (29 6%, p<0.05), whereas non-nasal contribution
increased (47 5% to 71 6%, p<0.05). Isocapneic hyperventilation
at rest increased exhaled NO output (51 8 to 94 22 nL/min/M2,
p=0.05). Dobutamine infusion did not increase exhaled NO output. We
conclude that nasal exhaled NO decreases (and non-nasal exhaled NO
increases) with exercise. We also conclude that, under conditions of
this study, increased exhaled NO output during exercise is more
closely related to increased ventilation than to increased blood
flow.
Received 18 July 1995; accepted in final form 12 January 1996.
APS Manuscript Number A780-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 29 January 96