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Effect of hypoxia on metabolic rate in awake ponies. J Appl Physiol (1985) 1994 Jun;76(6):2380-5



Pubmed ID




Scopus ID

2-s2.0-0028200270   13 Citations


To determine the effect of hypoxia on metabolic rate (VO2) of ponies, on 2 days we studied ponies that were breathing room air for 1 h followed by 5 h of either hypoxic hypoxia (fractional concn of inspired O2 = 0.126) or 5 h of CO hypoxia. Control arterial PO2 was 103 +/- 1.2 Torr, and at 5 min and 5 h of hypoxic hypoxia, arterial PO2 was 53.1 +/- 1.8 and 41.0 +/- 1.8 Torr, respectively. There was a time-dependent hypocapnia and alkalosis during hypoxic hypoxia. During CO hypoxia, carboxyhemoglobin increased to 25% after 30 min and remained constant thereafter. With increased carboxyhemoglobin, arterial PCO2 was 1.3 Torr above (P < 0.05) and 1.5 Torr (P < 0.05) below control levels after 30 min and 3 h, respectively. There were no significant (P > 0.10) changes in VO2 during either hypoxic or CO hypoxia. However, in 50% of the ponies, VO2, pulmonary ventilation, and rectal temperature increased and shivering was evident after 30 min of hypoxia. Peak values of pulmonary ventilation, VO2, and shivering occurred at approximately 2 h with a subsequent return toward control levels. We conclude that, in contrast to smaller mammals, acute hypoxia does not depress VO2 of ponies. The hypermetabolism and hyperthermia during chronic hypoxia in some ponies may reflect a transient failure in thermoregulation.

Author List

Korducki MJ, Forster HV, Lowry TF, Forster MM


Hubert V. Forster PhD Professor in the Physiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Blood Gas Analysis
Body Temperature
Carbon Dioxide
Hydrogen-Ion Concentration
Oxygen Consumption
Respiratory Function Tests
jenkins-FCD Prod-466 5b81815b8b3d1f46bfec16512ed5f574613f59c5