Why was this study done?

It is thought that fatigue in athletes may be brought on by many factors, but dehydration (and loss of plasma volume) may be one of the most important of these. This study was designed to help understand the importance of rehydration formulas and different rehydration strategies in the maintenance of plasma volume.

What did the study find?

The study discovered that the composition of a rehydration formula was more important to returning plasma volume to normal than the degree of dehydration or how quickly a drink was consumed.

Hypervolemia in men from fluid ingestion at rest and during exercise. Aviat Space Environ Med.
Authors: Greenleaf JE, Looft-Wilson R, Wisherd JL, Jackson CG, Fung PP, Ertl AC, Barnes PR, Jensen CD, Whittam JH. 1998 Apr;69(4):374-86.
PubMed Citation PMID: 9561285.
PDF Manuscript: Aviat Space Environ Med, 1998.

Earlier Paper:

Greenleaf JE, et al. Hypervolemia in Men from Drinking Hyperhydration Fluids at Rest and During Exercise. NASA Tech Memo, 1994. December: p. 46-57.PDF Abstract: NASA Tech Memo, 1994.