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Article: Dynamics of the ventilatory response in man to step changes of end-tidal carbon dioxide and of hypoxia during exercise

TitleDynamics of the ventilatory response in man to step changes of end-tidal carbon dioxide and of hypoxia during exercise
Authors
KeywordsAnoxia/blood/*physiopathology
Carbon Dioxide/blood
Exercise/*physiology
Humans
Male
Reflex/physiology
Respiration/*physiology
Issue Date1992
PublisherThe Physiological Society. The Journal's web site is located at http://www.physoc.org/journal-physiology
Citation
Journal of Physiology, 1992, v. 457, p. 539-557 How to Cite?
Abstract1. Four human subjects exercised in hypoxia (end-tidal partial pressure of O2 (P(ET),O2) ca 55 Torr; heart rate ca 100-130 beats min-1), and the contribution to the respiratory drive of the peripheral and central chemoreflex pathways have been separated on the basis of the latencies and the time courses of the responses to sudden changes of stimulus. 2. The subjects were exposed to repeated end-tidal step changes in PCO2 of ca 3-3.5 Torr (at nearly constant P(ET),O2) and PO2 (between ca 55 and 230 Torr) at three regions along the expiratory ventilation VE-P(ET),CO2 response line (hypocapnia, eucapnia, hypercapnia). The dynamics of the ventilatory responses were calculated using a two-compartment non-linear least-squares optimization method. 3. The component of the response attributable to the peripheral chemoreflex loop may in some subjects contribute up to 75% of the ventilatory drive during mild hypocapnic hypoxic exercise and ca 72% of the total gain following steps of P(ET),CO2 during hypoxic exercise. These data support the notion that the effectiveness of the peripheral chemoreceptor pathway is enhanced in moderate exercise. 4. During hypoxic exercise, the time delays and time constants attributed to the peripheral chemoreflex pathways (ca 3.5 and 9 s respectively) and to the central chemoreflex pathways (ca 9.5 and 47 s respectively) are some of the shortest reported. 5. The dynamics of the peripheral and central chemoreflex pathways appeared to be largely independent of each other. 6. There was a notable absence of systematic change of inspiratory and expiratory durations during the step-induced transients.
Persistent Identifierhttp://hdl.handle.net/10722/197035
ISSN
2015 Impact Factor: 4.731
2015 SCImago Journal Rankings: 2.670
PubMed Central ID
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorMacfarlane, DJen_US
dc.contributor.authorCunningham, DJen_US
dc.date.accessioned2014-05-07T06:43:11Z-
dc.date.available2014-05-07T06:43:11Z-
dc.date.issued1992en_US
dc.identifier.citationJournal of Physiology, 1992, v. 457, p. 539-557en_US
dc.identifier.issn0022-3751en_US
dc.identifier.urihttp://hdl.handle.net/10722/197035-
dc.description.abstract1. Four human subjects exercised in hypoxia (end-tidal partial pressure of O2 (P(ET),O2) ca 55 Torr; heart rate ca 100-130 beats min-1), and the contribution to the respiratory drive of the peripheral and central chemoreflex pathways have been separated on the basis of the latencies and the time courses of the responses to sudden changes of stimulus. 2. The subjects were exposed to repeated end-tidal step changes in PCO2 of ca 3-3.5 Torr (at nearly constant P(ET),O2) and PO2 (between ca 55 and 230 Torr) at three regions along the expiratory ventilation VE-P(ET),CO2 response line (hypocapnia, eucapnia, hypercapnia). The dynamics of the ventilatory responses were calculated using a two-compartment non-linear least-squares optimization method. 3. The component of the response attributable to the peripheral chemoreflex loop may in some subjects contribute up to 75% of the ventilatory drive during mild hypocapnic hypoxic exercise and ca 72% of the total gain following steps of P(ET),CO2 during hypoxic exercise. These data support the notion that the effectiveness of the peripheral chemoreceptor pathway is enhanced in moderate exercise. 4. During hypoxic exercise, the time delays and time constants attributed to the peripheral chemoreflex pathways (ca 3.5 and 9 s respectively) and to the central chemoreflex pathways (ca 9.5 and 47 s respectively) are some of the shortest reported. 5. The dynamics of the peripheral and central chemoreflex pathways appeared to be largely independent of each other. 6. There was a notable absence of systematic change of inspiratory and expiratory durations during the step-induced transients.en_US
dc.languageengen_US
dc.publisherThe Physiological Society. The Journal's web site is located at http://www.physoc.org/journal-physiology-
dc.relation.ispartofJournal of Physiologyen_US
dc.subjectAnoxia/blood/*physiopathologyen_US
dc.subjectCarbon Dioxide/blooden_US
dc.subjectExercise/*physiologyen_US
dc.subjectHumansen_US
dc.subjectMaleen_US
dc.subjectReflex/physiologyen_US
dc.subjectRespiration/*physiologyen_US
dc.titleDynamics of the ventilatory response in man to step changes of end-tidal carbon dioxide and of hypoxia during exerciseen_US
dc.typeArticleen_US
dc.identifier.emailMacfarlane, DJ: djmac@hku.hken_US
dc.identifier.authorityMacfarlane, DJ=rp00934en_US
dc.description.naturelink_to_OA_fulltext-
dc.identifier.pmid1297845en_US
dc.identifier.pmcidPMC1175746en_US
dc.identifier.volume457en_US
dc.identifier.spage539en_US
dc.identifier.epage557en_US
dc.identifier.isiWOS:A1992JY70500032-

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