Document Detail

Evolution of inspiratory and expiratory muscle pressures during endurance exercise.
MedLine Citation:
PMID:  10642386     Owner:  NLM     Status:  MEDLINE    
We investigated the relationship between minute ventilation (VE) and net respiratory muscle pressure (Pmus) throughout the breathing cycle [Total Pmus = mean Pmus, I (inspiratory) + mean Pmus, E (expiratory)] in six normal subjects performing constant-work heavy exercise (CWHE, at approximately 80% maximum) to exhaustion on a cycle ergometer. Pmus was calculated as the sum of chest wall pressure (elastic + resistive) and pleural pressure, and all mean Pmus variables were averaged over the total breath duration. Pmus, I was also expressed as a fraction of volume-matched, flow-corrected dynamic capacity of the inspiratory muscles (P(cap, I)). VE increased significantly from 3 min to the end of CWHE and was the result of a significantly linear increase in Total Pmus (Delta = 43 +/- 9% from 3 min to end exercise, P < 0.005) in all subjects (r = 0. 81-0.99). Although mean Pmus, I during inspiratory flow increased significantly (Delta = 35 +/- 10%), postinspiratory Pmus, I fell (Delta = -54 +/- 10%) and postexpiratory expiratory activity was negligible or absent throughout CWHE. There was a greater increase in mean Pmus, E (Delta = 168 +/- 48%), which served to increase VE throughout CWHE. In five of six subjects, there were significant linear relationships between VE and mean Pmus, I (r = 0.50-0.97) and mean Pmus, E (r = 0.82-0.93) during CWHE. The subjects generated a wide range of Pmus, I/P(cap, I) values (25-80%), and mean Pmus, I/P(cap, I) increased significantly (Delta = 42 +/- 16%) and in a linear fashion (r = 0.69-0.99) with VE throughout CWHE. The progressive increase in VE during CWHE is due to 1) a linear increase in Total Pmus, 2) a linear increase in inspiratory muscle load, and 3) a progressive fall in postinspiratory inspiratory activity. We conclude that the relationship between respiratory muscle pressure and VE during exercise is linear and not curvilinear.
B S Krishnan; T Zintel; C McParland; C G Gallagher
Related Documents :
17134946 - Inspiratory muscles do not limit maximal incremental exercise performance in healthy su...
2318766 - Inspiratory and expiratory muscle perfusion in maximally exercised ponies.
3965266 - Inspiratory muscle conditioning using a threshold loading device.
2766816 - Coordination of eating, drinking and breathing in adults.
8433136 - An investigation of the coupling between respiration, mastication, and swallowing in th...
3128316 - Automated non-invasive measurement of cardiac output: comparison of electrical bioimped...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  88     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2000 Jan 
Date Detail:
Created Date:  2000-03-28     Completed Date:  2000-03-28     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  234-45     Citation Subset:  IM; S    
Division of Respiratory Medicine, Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 0W8.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Exercise / physiology*
Linear Models
Lung Volume Measurements
Physical Endurance / physiology*
Pulmonary Ventilation / physiology*
Respiratory Muscles / physiology*
Tidal Volume
Time Factors

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Effects of exercise on muscle transverse relaxation determined by MR imaging and in vivo relaxometry...
Next Document:  Women at altitude: carbohydrate utilization during exercise at 4,300 m.