Skip to main content
PMC home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1996 Aug 1;494(Pt 3):881–890. doi: 10.1113/jphysiol.1996.sp021540

Respiratory mechanics during exhaustive submaximal exercise at high altitude in healthy humans.

F Cibella 1, G Cuttitta 1, B Kayser 1, M Narici 1, S Romano 1, F Saibene 1
PMCID: PMC1160685  PMID: 8865082

Abstract

1. The present investigation was conducted to test the hypothesis that the respiratory system is stressed more during exhaustive exercise in chronic hypoxia than in normoxia. 2. Four healthy male subjects (aged 33-35 years) exercised on a cycle ergometer at 75% of the local maximum oxygen consumption (Vo2,max) until exhaustion, at sea level (SL) and after a 1 month stay at 5050 m (HA). 3. Airflow at the mouth (V), oesophageal (Po) and gastric (Pg) pressures were measured at rest, during exercise and recovery. Minute ventilation (VE), respiratory power (Wresp), respiratory frequency (f) and transdiaphragmatic pressure (Pdi) were calculated from the measured variables. 4. The subjects' mechanical power output of cycling at HA was 23.7% lower than at SL. In spite of this reduction, time to exhaustion at HA was 55.3% less than at SL. VE increased slightly during exercise at SL, but showed a marked increase at HA, and at the end of exercise at HA was 47.3% higher than at SL. 5. Respiratory power increased more at HA than at SL (77.3% higher at the end of exercise) due to the increase in f needed to sustain the high VE. 6. Gastric pressure swings were negative at the end of HA exercise but always positive at SL. The Pai:Po ratio reached values below 1 at HA but never at SL. 7. These data seem to indicate that the respiratory system is stressed more during submaximal exercise at HA than at SL. We suggest that the exceedingly high VE demand, requiring an excessive Wresp, may lead to fatigue of the diaphragm.

Full text

PDF
890

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Aaron E. A., Seow K. C., Johnson B. D., Dempsey J. A. Oxygen cost of exercise hyperpnea: implications for performance. J Appl Physiol (1985) 1992 May;72(5):1818–1825. doi: 10.1152/jappl.1992.72.5.1818. [DOI] [PubMed] [Google Scholar]
  2. Babcock M. A., Johnson B. D., Pegelow D. F., Suman O. E., Griffin D., Dempsey J. A. Hypoxic effects on exercise-induced diaphragmatic fatigue in normal healthy humans. J Appl Physiol (1985) 1995 Jan;78(1):82–92. doi: 10.1152/jappl.1995.78.1.82. [DOI] [PubMed] [Google Scholar]
  3. Baydur A., Behrakis P. K., Zin W. A., Jaeger M., Milic-Emili J. A simple method for assessing the validity of the esophageal balloon technique. Am Rev Respir Dis. 1982 Nov;126(5):788–791. doi: 10.1164/arrd.1982.126.5.788. [DOI] [PubMed] [Google Scholar]
  4. Bellemare F., Grassino A. Effect of pressure and timing of contraction on human diaphragm fatigue. J Appl Physiol Respir Environ Exerc Physiol. 1982 Nov;53(5):1190–1195. doi: 10.1152/jappl.1982.53.5.1190. [DOI] [PubMed] [Google Scholar]
  5. Bye P. T., Esau S. A., Walley K. R., Macklem P. T., Pardy R. L. Ventilatory muscles during exercise in air and oxygen in normal men. J Appl Physiol Respir Environ Exerc Physiol. 1984 Feb;56(2):464–471. doi: 10.1152/jappl.1984.56.2.464. [DOI] [PubMed] [Google Scholar]
  6. Gallagher C. G., Hof V. I., Younes M. Effect of inspiratory muscle fatigue on breathing pattern. J Appl Physiol (1985) 1985 Oct;59(4):1152–1158. doi: 10.1152/jappl.1985.59.4.1152. [DOI] [PubMed] [Google Scholar]
  7. Green H. J., Sutton J., Young P., Cymerman A., Houston C. S. Operation Everest II: muscle energetics during maximal exhaustive exercise. J Appl Physiol (1985) 1989 Jan;66(1):142–150. doi: 10.1152/jappl.1989.66.1.142. [DOI] [PubMed] [Google Scholar]
  8. Jardim J., Farkas G., Prefaut C., Thomas D., Macklem P. T., Roussos C. The failing inspiratory muscles under normoxic and hypoxic conditions. Am Rev Respir Dis. 1981 Sep;124(3):274–279. doi: 10.1164/arrd.1981.124.3.274. [DOI] [PubMed] [Google Scholar]
  9. Johnson B. D., Babcock M. A., Suman O. E., Dempsey J. A. Exercise-induced diaphragmatic fatigue in healthy humans. J Physiol. 1993 Jan;460:385–405. doi: 10.1113/jphysiol.1993.sp019477. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Loke J., Mahler D. A., Virgulto J. A. Respiratory muscle fatigue after marathon running. J Appl Physiol Respir Environ Exerc Physiol. 1982 Apr;52(4):821–824. doi: 10.1152/jappl.1982.52.4.821. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES