Energy Supplements to Improve Exercise Tolerance in Metabolic Myopathies

It has recently been documented how patients with GSDIIIa have a moderate to severely reduced exercise capacity, and that exercise induces muscle pain and cramps. These symptoms are caused by the inability to mobilize skeletal muscle glycogen and are most likely the consequence of a severe energy deficiency within muscles. The study changed the phenotype of GSDIIIa, to include exercise-induced symptoms, which is a typical presentation in other metabolic myopathies. It also documented that exercise capacity was significantly improved while exercise-induced muscular symptoms were relieved by an intravenous glucose infusion. Based on these findings, this study wishes to investigate if oral ingestion of sucrose has the same effects on work capacity on a larger number of patients, in a randomized, placebo-controlled, cross-over setup. Ingestion of sucrose has the potential to be an effective, cheap and easily accessible dietary treatment of muscular symptoms in GSDIIIa.