| Regulation of end-expiratory lung volume during exercise. | |
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MedLine Citation:
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PMID: 3356631 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We determined the effects of exercise on active expiration and end-expiratory lung volume (EELV) during steady-state exercise in 13 healthy subjects. We also addressed the questions of what affects active expiration during exercise. Exercise effects on EELV were determined by a He-dilution technique and verified by changes in end-expiratory esophageal pressure. We also used abdominal pressure-volume loops to determine active expiration. EELV was reduced with increasing exercise intensity. EELV was reduced significantly during even mild steady-state exercise and during heavy exercise decreased an average of 0.71 +/- 0.3 liter. Dynamic lung compliance was reduced 30-50%; EELV remained greater than closing volume. Changing the resistance to airflow (via SF6-O2 or He-O2 breathing) during steady-state exercise changed the peak gastric and esophageal pressure generation during expiration but did not alter EELV; breathing through the mouthpiece produced similar effects during exercise. EELV was significantly reduced in the supine position. With supine exercise active expiration was not elicited, and EELV remained the same as in supine rest. With CO2-driven hyperpnea (7-70 l/min), EELV remained unchanged from resting levels, whereas during exercise, at similar minute ventilation (VE) values EELV was consistently decreased. At the same VE, treadmill running caused an increase in tonic gastric pressure and greater reductions in EELV than either walking or cycling. We conclude that both the exercise stimulus and the resultant hyperpnea stimulate active expiration and a reduced FRC. This new EELV is preserved in the face of moderate changes in mechanical time constants of the lung. This reduced EELV during exercise aids inspiration by optimizing diaphragmatic length and permitting elastic recoil of the chest wall. |
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Authors:
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K G Henke; M Sharratt; D Pegelow; J A Dempsey |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 64 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1988 Jan |
Date Detail:
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Created Date: 1988-05-13 Completed Date: 1988-05-13 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 135-46 Citation Subset: IM; S |
Affiliation:
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John Rankin Laboratory of Pulmonary Medicine, Department of Preventive Medicine, University of Wisconsin Medical School, Madison 53705. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Female Functional Residual Capacity Humans Lung Compliance Lung Volume Measurements Male Middle Aged Physical Exertion* Posture Respiration* |
| Grant Support | |
ID/Acronym/Agency:
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HL-15469/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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