MODIFICATION OF THE RESPONSES OF ENDOTHELIN-1 TO EXHAUSTIVE PHYSICAL EXERCISE UNDER SIMULATED HIGH-ALTITUDE CONDITIONS WITH ACUTE-HYPOXIA

To assess whether acute alveolar hypoxia leads to the release of endot helin-l (ET) in vivo, ET, cortisol (CORT), and lactate (LA) levels wer e determined in 15 healthy subjects at rest and during exhaustive incr emental cycle ergometry on two separate test days. The subjects were t o breathe a gas mixture with reduced O-2 content ([H] fraction of insp ired O-2, 0.14) On one day and normal air on the other (N). Modified r esponses of LA and CORT to exhaustive incremental cycle ergometry on t he H day indicated elevated anaerobic tissue metabolism and increased physical stress. With acute alveolar hypoxia, the response of ET to ex haustive physical labor was found to be augmented. Copyright (C) 1995 by W.B. Saunders Company