Respiratory effort sensation during exercise with induced expiratory-flow limitation in healthy humans

• Published in: Journal of applied physiology (1985) 1997-09, Vol.83 (3), p.936-947
• Main Authors: Kayser, Bengt, Sliwinski, Pawel, Yan, Sheng, Tobiasz, Mirek, Macklem, Peter T
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Carbon Dioxide - blood; Chronic obstructive pulmonary disease, asthma; Diaphragm - physiology; Exercise - physiology; Exercise Test; Female; Humans; Male; Medical sciences; Models, Biological; Pneumology; Regression Analysis; Respiratory Function Tests; Respiratory Mechanics - physiology; Respiratory Muscles - physiology; Space life sciences
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1997.83.3.936

Bengt Kayser, Pawel Sliwinski, Sheng Yan, Mirek Tobiasz, and Peter T. Macklem Meakins-Christie Laboratories, McGill University Clinics, Montreal, Quebec, Canada H2X 2P2 Received 13 May 1996; accepted in final form 10 June 1997. Kayser, Bengt, Pawel Sliwinski, Sheng Yan, Mirek Tobiasz, and Peter T. Macklem. Respiratory effort sensation during exercise with induced expiratory-flow limitation in healthy humans. J. Appl. Physiol. 83(3): 936-947, 1997. Nine healthy subjects (age 31 ± 4 yr) exercised with and without expiratory-flow limitation (maximal flow ~1 l/s). We monitored flow, end-tidal P CO 2 , esophageal (Pes) and gastric pressures, changes in end-expiratory lung volume, and perception (sensation) of difficulty in breathing. Subjects cycled at increasing intensity (+25 W/30 s) until symptom limitation. During the flow-limited run, exercise performance was limited in all subjects by maximum sensation. Sensation was equally determined by inspiratory and expiratory pressure changes. In both runs, 90% of the variance in sensation could be explained by the Pes swings (difference between peak inspiratory and peak expiratory Pes). End-tidal P CO 2 did not explain any variance in sensation in the control run and added only 3% to the explained variance in the flow-limited run. We conclude that in healthy subjects, during normal as well as expiratory flow-limited exercise, the pleural pressure generation of the expiratory muscles is equally related to the perception of difficulty in breathing as that of the inspiratory muscles. dynamic hyperinflation; chronic obstructive pulmonary disease; breathlessness; exercise limitation 0161-7567/97 $5.00 Copyright © 1997 the American Physiological Society