Elevated serum lactate following hyperventilation during glucose infusion in panic disorder.

Early investigators reported that patients with anxiety syndromes associated with panic attacks produced more lactate during exercise than control subjects. These studies suggested a metabolic difference between patients and controls. However, the possibility that patients were simply less fit than controls could not be excluded. In this study, serum lactate was measured in panic disorder patients in response to a metabolic challenge not involving exercise. Voluntary hyperventilation during iatrogenic hyperglycemia led to an increase in serum lactate. The increase in serum lactate was significantly greater in panic disorder patients than in controls. Hyperventilation provoked panic attacks in 4 of 8 patients and none in 6 controls. There was no evidence of a relationship between the increase in lactate or the associated decrease in phosphate and the level of anxiety produced by this procedure.