I would be interested to see a copy of this abstract. What exactly is Mr.
Robergs' point? Is he asserting that acidosis is not a factor in fatigue;
fatigue is not related to lactate accumulation during exercise; some other
metabolic substrate is involved with pH? Being somewhat familiar with
physiology, the contention that "lactate" and "lactic acid" are dissimilar
is incorrect. The "-ate" modifier is common nomenclature in chemical
analysis reserved for the identification of the hydrogen donor in solution.
Therefore, in biological systems, the term "lactate" is often synonomous
with "lactic acid." To take the literal stance on this word is merely
symantics. Lactate accumulation, and its accompanying H+ accumulation, is
local and is a derivative of O2 insufficiency. In biological systems,
lactate production is far removed from the energy chain because the energy
coupling involved with glycolosis in with the citric acid cycle favors ATP
production and complete glycolosis (despite some molecules of glucose
leading to lactate). Even when energy demands outpace the ATP production
locally and lactate accumulates (accompanied by the increased H+
concentration and thus lower pH) the increase in CO2 (a metabolic byproduct
of glycolosis) will trigger a neural response at the muscle causing a
sympathetic response to increase bloodflow at that location. The increased
O2 exchange at that point would create an energy environment that would
decrease the lactate concentration. Therefore, where is this pH being
measured, what substrates are being analyzed, and what type or level of
exertion is being used to create this environment?
Regards
Bob
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