Abstract
During incremental exercise to fatigue under hypobaric hypoxia, Andean Quechua natives
form and accumulate less plasma lactate than do lowlanders under similar conditions.
This phenomenon of low lactate accumulation despite hypobaric hypoxia, first discovered
some half century ago, is known in Quechuas to be largely unaffected by acute exposure
to hypoxia or by acclimatization to sea level conditions. Earlier Nuclear Magnetic
Resonance (NMR) spectroscopy and metabolic biochemistry studies suggest that closer
coupling of energy demand and energy supply in Quechuas allows given changes in work
rate with relatively modest changes in muscle adenylate and phosphagen concentrations,
thus tempering the activation of glycolytic flux to pyruvate - a coarse control mechanism
operating at the level of overall pathway flux. Later studies of enzyme activities
in skeletal muscles of Quechuas and of Sherpas have identified a finely-tuned control
mechanism which by adaptive modifications of a few key enzymes apparently serves to
specifically attenuate pyruvate flux to lactate.
Key words
Lactate paradox - Sherpa enzymes - Quechua enzymes
