1. Plasma concentrations of glucose, lactate, amino acids, non-esterified fatty acids, glycerol, ketone bodies, insulin and cortisol were measured in 43 elderly patients with hypothermia. In 15 of these patients forearm arteriovenous differences were also measured. Core temperatures ranged from 25.9 to 35.5°C.
2. The metabolic state was of mobilization of glycogen and triacylglycerol stores, with high plasma concentrations of lactate and lipid metabolites. The plasma concentration of glucose was raised in those with hypothermia of a short duration (<6 h). In other patients it was low in those with core temperatures around 30°C, but below this temperature it was variable and often high. Concentrations of other metabolites or hormones were not related to core temperature.
3. Plasma concentrations of cortisol were high and positively correlated with those of lactate and glycerol, suggesting active involvement in stimulation of muscle glycogenolysis and of lipolysis.
4. Plasma concentrations of insulin ranged from very low to very high and appeared to depend on the concentrations of both glucose and alanine.
5. Arteriovenous differences were generally small. There was peripheral release of lactate and of amino acids but no overall peripheral uptake of glucose. In nine out of 15 patients there was a significant peripheral release of glucose.
6. No differences in metabolism were observed between patients where the hypothermia appeared accidental and those with an obvious precipitating illness, despite a significantly lower mortality in the former group.
7. It was concluded that therapy should primarily involve rewarming of patients by physical means, without metabolic intervention.