Cardiovascular and Metabolic Responses to Exercise in a Patient with McArdle's Syndrome

Abstract

IN 1951 McArdle1 described a patient who was unable to exercise for more than five or ten minutes without becoming fatigued and who noted that his exercised muscles became stiff and swollen. A defect in the breakdown of muscle glycogen was postulated but not demonstrated. Several years later Schmid and Mahler2 and Pearson, Rimer and Mommaerts3 reported similar cases and demonstrated a lack of muscle phosphorylase "b". Subjects with this syndrome can exercise for a longer time during intravenous infusion of a variety of substrates including glucose,1 2 3 fructose, lactate and emulsified fat.3 In addition, Pearson et al.3 noted that exercise . . .