| Influence of inspiratory assistance on ventilatory control during moderate exercise. | |
| | |
MedLine Citation:
|
PMID: 3549674 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
In five healthy subjects, we studied the effects of controlled mechanical unloading of the respiratory system on ventilatory control during moderate exercise, utilizing a modified positive-pressure ventilator (IEEE Trans. Biomed. Eng. BME-33: 361-365, 1986). We were especially interested in whether isocapnia was maintained when a portion of the normal ventilatory response to constant-load cycling was subserved by the ventilator. The mechanical unloading was achieved by "assisting" airflow throughout inspiration in a constant proportion to instantaneous flow. Two modest degrees of assistance (A1 = 1.5 and A2 = 3.0 cmH2O X l-1 X s) were imposed. The assistance caused minute ventilation (VE) to increase immediately (inspiratory time shortening and tidal volume rising) and end-tidal PCO2 (PETCO2) to fall. Some 10-15 s later, inspiratory occlusion pressure (P100) decreased, and in the new steady-state VE and PETCO2 were virtually restored to their control exercise levels. The modest residual hyperventilation [delta PETCO2 = -0.9 Torr (A1) and -1.6 Torr (A2)], which was not significant statistically, contrasted markedly with the much larger increase predicted for VE had there been no compensatory reduction in ventilatory drive (as evidenced by the fall in P100). Consistent with earlier studies utilizing resistive loading (J. Appl. Physiol. 35: 361-366, 1973 and Acta Physiol. Scand. 120: 557-565, 1984), these observations suggest that ventilatory drive during moderate exercise is controlled to compensate for modest changes in respiratory-mechanical load, so that VE is preserved at a level appropriate to metabolic rate or nearly so. |
| | |
Authors:
|
C S Poon; S A Ward; B J Whipp |
Related Documents
:
|
21221344 - Back exercises: what patients are taught and what they do. 8082364 - Analysis of the inspiratory flow-volume curve. should it always precede the forced expi... 7204184 - Effects of added inspiratory loads on load detection thresholds. 11959644 - Sildenafil-nitric oxide donor combination promotes ventricular tachyarrhythmias in the ... 17364944 - Electron paramagnetic spectroscopic evidence of exercise-induced free radical accumulat... 7091354 - Lack of influence of potassium or osmolality on steady-state exercise hyperemia. |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 62 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1987 Feb |
Date Detail:
|
Created Date: 1987-05-18 Completed Date: 1987-05-18 Revised Date: 2008-11-21 |
Medline Journal Info:
|
Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 551-60 Citation Subset: IM; S |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Adult Humans Physical Exertion* Physiology / instrumentation Positive-Pressure Respiration* Respiration* Tidal Volume Work of Breathing |
| Grant Support | |
ID/Acronym/Agency:
|
HL-30794/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Central chemoreceptors.
Next Document: Effects of airway pressure on bronchial blood flow.