Effect of Oral Sucrose Shortly Before Exercise on Work Capacity in McArdle Disease | Lifestyle Behaviors | JAMA Neurology | JAMA Network
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Original Contribution
June 2008

Effect of Oral Sucrose Shortly Before Exercise on Work Capacity in McArdle Disease

Author Affiliations

Author Affiliations: Neuromuscular Research Unit, Department of Neurology, and the Copenhagen Muscle Research Center, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark (Drs Andersen and Vissing); and Neuromuscular Center and Institute for Exercise and Environmental Medicine of Presbyterian Hospital, Department of Neurology, Veteran Affairs Medical Center, and the University of Texas, Southwestern Medical Center, Dallas (Dr Haller).

Arch Neurol. 2008;65(6):786-789. doi:10.1001/archneur.65.6.786

Background  Oral sucrose (75 g) ingested 40 minutes before exercise improves exercise tolerance in McArdle disease.

Objective  To determine whether a lower dose of sucrose administered closer in time to exercise could have a similar beneficial effect on exercise capacity in patients with McArdle disease.

Design  Placebo-controlled crossover.

Setting  Neuromuscular Research Unit at the Department of Neurology, Rigshospitalet, Copenhagen, Denmark.

Patients  Six patients with biochemically and genetically diagnosed McArdle disease.

Interventions  On separate days, the patients were tested after ingestion of either 75 g of sucrose or a placebo 40 minutes before exercise, or 37 g of sucrose or a placebo 5 minutes before exercise. Patients were blinded to test substances.

Main Outcome Measures  Treatment effectiveness was assessed by monitoring heart rate and perceived exertion during exercise.

Results  Both sucrose treatments dramatically improved exercise tolerance, compared with the placebo. The low-dose, 5-minute sucrose trial had a more sustained effect on exercise capacity than the 40-minute trial. The more sustained effect was probably related to more continuous glucose uptake from the intestine and correspondingly higher circulating glucose levels later during exercise.

Conclusions  This study shows that 37 g of sucrose ingested shortly before exercise has a marked and prolonged effect on exercise tolerance in patients with McArdle disease. This treatment is more convenient for the patients and saves more calories than the currently recommended sucrose treatment.