"Common sports drinks like Gatorade, Allsport and Powerade are less than optimum for rehydration purposes because they contain no magnesium."

Exercise or athletic activity can influence nutritional magnesium status, and magnesium status can influence physical performance ...

Exercisers who feel weak and tired may be suffering from "the mineral blues," says Gabe Mirkin, M.D., coauthor of the Sportsmedicine Book.

Magnesium is involved in numerous processes that affect muscle function including oxygen uptake, energy production and electrolyte balance.