Blood ammonia and ventilation at maximal exercise

This study, intended to evaluate the role of ammonia (NH 3) as a ventilatory stimulus, was conducted in three groups of subjects: 14 sedentary individuals, 12 triathletes, 5 patients with a glycolytic deficiency (Mc Ardle disease). All subjects performed maximal exercise tests on a cycle ergometer. Ventilation measured at maximal oxygen consumption (V E 100%) was correlated with lactatemia (lactate 100%) and ammonemia (NH 3 100%) in the sedentary group, but only with ammonemia in triathletes, although NH 3 100% and lactate 100% were correlated in both groups, which suggests that correlation between V E 100% and NH 3 100% is not a false correlation. In patients with Mc Ardle disease, unable to produce lactate during exercise, V E 100% was correlated with NH 3 100%. NH 3 may act indirectly by increasing the production of lactate in cerebral tissue. Another hypothesis rests on the fact t hat the catabolism of ammonia leads to an increase in intracerebral glutamate which may act as a ventilatory stimulus.