A double blind, placebo controlled, crossover trial of D-ribose in McArdle's disease.

To determine whether seven days oral D-ribose would improve exercise tolerance in a group of 5 patients with McArdle's disease, we performed a double blind placebo controlled crossover trial. Subjects performed weekly treadmill exercise tests with expired gas analysis until their times were reproducible. They then received 60 g D-ribose daily or placebo for seven days. Exercise testing was repeated on completion of this period. A seven day washout period then followed. Subjects then performed a new baseline exercise test prior to starting the other solution. Again after seven days the exercise test was repeated. There was no significant difference between pre-treatment exercise tests for peak oxygen consumption or level of leg fatigue. Patients did not like taking the ribose and D-Ribose does not appear to be of benefit to patients with McArdle's disease.