Why was this study done?

Athletes who engage in long exercise bouts have an interest in sparing muscle glycogen (short-term storage of glucose) because of the dramatic reduction of energy output and fatigue that occurs when glycogen is depleted (known colloquially as “hitting the wall”). This study was designed to help understand how varying exercise intensity along with carbohydrate ingestion effects glycogen storage.

What did the study find?

The study found that continuous carbohydrate supplementation (in the form of a rehydration formula) during exercise was successful at preventing glycogen loss and also increased the time to fatigue.

Carbohydrate supplementation spares muscle glycogen during variable-intensity exercise
Authors: Yaspelkis BB, Patterson JG, Anderla PA, Ding Z, Ivy JL. J Appl Physiol (1985). 1993 Oct;75(4):1477-85.
PubMed Citation PMID: 8282593.
PDF Manuscript: J Appl Physiol, 1993.