TY - JOUR
T1 - Hyperventilation with He-O2 breathing is not decreased by superimposed external resistance
AU - Babb, Tony G.
AU - DeLorey, Darren S.
N1 - Funding Information:
The authors wish to thank Brenda L. Wyrick and Penny P. Gardner for their assistance throughout the various stages of this project. The authors also wish to acknowledge their appreciation to Dr Benjamin D. Levine for the medical assistance with this project. This work was supported by NIH grant: NIA-AG11805.
PY - 2002/10/23
Y1 - 2002/10/23
N2 - The purpose of this study was to determine the effect of imposed external resistance on the ventilatory response to He-O2 breathing during peak exercise. To accomplish this purpose, separate inspiratory and expiratory external resistances were applied to offset for the decrease in intrapulmonary airway resistance with He-O2 breathing. Seven men and three women (69±3 years, mean±S.D.) with normal pulmonary function performed graded cycle ergometry to exhaustion breathing room air, He-O2 (79% He, 21% O2), He-O2 with imposed expiratory resistance, and He-O2 with imposed inspiratory resistance. Ventilation (V̇E), lung mechanics, and PETCO2 were measured during each 1 min increment in work rate and were analyzed by one-way ANOVA for repeated measures at rest, ventilatory threshold (VTh), and peak exercise. In response, V̇E was increased and PETCO2 was decreased at VTh (P<0.01) and peak exercise (P<0.01) whenever breathing He-O2. Thus, V̇E was increased during exercise above VTh with He-O2 breathing regardless of increases in inspiratory or expiratory external resistance. In conclusion, these data suggest that inspiratory resistive unloading is no more important than expiratory resistive unloading to the increase in V̇E with He-O2 breathing during heavy and peak exercise.
AB - The purpose of this study was to determine the effect of imposed external resistance on the ventilatory response to He-O2 breathing during peak exercise. To accomplish this purpose, separate inspiratory and expiratory external resistances were applied to offset for the decrease in intrapulmonary airway resistance with He-O2 breathing. Seven men and three women (69±3 years, mean±S.D.) with normal pulmonary function performed graded cycle ergometry to exhaustion breathing room air, He-O2 (79% He, 21% O2), He-O2 with imposed expiratory resistance, and He-O2 with imposed inspiratory resistance. Ventilation (V̇E), lung mechanics, and PETCO2 were measured during each 1 min increment in work rate and were analyzed by one-way ANOVA for repeated measures at rest, ventilatory threshold (VTh), and peak exercise. In response, V̇E was increased and PETCO2 was decreased at VTh (P<0.01) and peak exercise (P<0.01) whenever breathing He-O2. Thus, V̇E was increased during exercise above VTh with He-O2 breathing regardless of increases in inspiratory or expiratory external resistance. In conclusion, these data suggest that inspiratory resistive unloading is no more important than expiratory resistive unloading to the increase in V̇E with He-O2 breathing during heavy and peak exercise.
KW - Exercise, external resistance, He-O
KW - Gases, inspired, He-O
KW - Mammals, humans
KW - Resistance, external
KW - Ventilation, He-O breathing
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U2 - 10.1016/S1569-9048(02)00165-9
DO - 10.1016/S1569-9048(02)00165-9
M3 - Article
C2 - 12385739
AN - SCOPUS:0037163847
SN - 1569-9048
VL - 133
SP - 139
EP - 151
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
IS - 1-2
ER -