Why was this study done?

Changes in altitude effect absorption and distribution of water and electrolytes in the body. This study was designed to understand how differing rehydration formulas (containing different concentrations of electrolytes) are effected by altitude.

What did the study find?

This study found that induction and maintenance of hypervolemia at altitude relies more on ionic minerals and a nearly isotonic drink rather non-ionic minerals.

Plasma sodium-osmotic dissociation and hormonal interaction with drinking-induced hypervolemia at 2800 m altitude.
Authors: Greenleaf JE, Hinghofer-Szalkay H, Rössler A, Farrell PA, Loomis JL, Fedele MJ, West J, Cowell SA. Aviat Space Environ Med. 2001 Jun;72(6):522-8.
PubMed Citation, PMID: 11396557.