Effect of chronic alcohol intake on energy metabolism in human muscle

We investigated the effect of alcohol on muscle energy metabolism by using 31P magnetic resonance spectroscopy in 12 chronic alcoholics [6 with neurological signs and symptoms (such as cerebellar ataxia or diplopia) and 6 without neurological signs or symptoms], compared with five healthy subjects who also received acute alcohol loading. Intracellular pH and phosphocreatine (PCr) index [PCr/ (PCr + Pi)] were measured during rest, exercise, and recovery in the left flexor digitorum superficialis muscle. In healthy subjects, acute alcohol loading did not influence the changes of muscle pH and PCr index. Alcoholics with neurological signs showed marked decreases in muscle intracellular pH and PCr index during exercise and a marked delay of pH recovery after exercise. There was no delay of PCr index recovery. Alcoholics without neurological signs showed slight decreases in intracellular pH and PCr index, but rapid recovery of both intracellular pH and PCr index was observed. Marked decrease and delayed recovery in pH, but rapid recovery of PCr index, indicate that the muscle of patients with neurological signs produced lactate during and after exercise to maintain the ATP level, which implies that anaerobic metabolism is favored over aerobic metabolism in these patients.