The direct effects of hypoxia on exercise-induced breathlessness are unclear. Increased breathlessness on exercise is known to occur at high altitude, but it is not known whether this is related to the hypoxia per se, or to other ventilatory parameters. To examine the role of high-altitude hypoxia in exercise-induced breathlessness, studies were performed in 10 healthy, normal subjects at sea level and after acute exposure to an altitude of 4450 ;m. Although the perception of hand weights did not alter between sea level and high altitude, the intensity of exercise-induced breathlessness increased significantly at high altitude. This was associated with a higher minute ventilation and respiratory frequency for any given exercise level, whereas tidal volume was not significantly altered from sea level values. The increased intensity of breathlessness with exercise did not change significantly over the 5 days at high altitude. These results suggest that the increased intensity of exercise-induced breathlessness at high altitude is not related to peripheral mechanisms or the pattern of ventilation, or to the level of hypoxia per se, but to the level of reflexly increased ventilation.
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Research Article|
April 01 1999
Effects of acute prolonged exposure to high-altitude hypoxia on exercise-induced breathlessness
Nausherwan K. BURKI;
*Division of Pulmonary and Critical Care Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, U.S.A.
†Department of Physiology and Biophysics, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, U.S.A., and
Correspondence: Professor N. K. Burki.
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J. Wesley MCCONNELL;
J. Wesley MCCONNELL
*Division of Pulmonary and Critical Care Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, U.S.A.
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Mohammad AYUB;
Mohammad AYUB
‡Department of Physiology, Ayub Medical College, Abbottabad, Pakistan
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Richard M. LILES
Richard M. LILES
*Division of Pulmonary and Critical Care Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, U.S.A.
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Publisher: Portland Press Ltd
Online ISSN: 1470-8736
Print ISSN: 0143-5221
The Biochemical Society and the Medical Research Society © 1999
1999
Clin Sci (Lond) (1999) 96 (4): 327–333.
Citation
Nausherwan K. BURKI, J. Wesley MCCONNELL, Mohammad AYUB, Richard M. LILES; Effects of acute prolonged exposure to high-altitude hypoxia on exercise-induced breathlessness. Clin Sci (Lond) 1 April 1999; 96 (4): 327–333. doi: https://doi.org/10.1042/cs0960327
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