A new study led by researchers at the University of West Virginia indicates that performance-enhancing supplements may be the reason for the growing number of high school and college football players who have died from heat stroke. Researchers say supplements such as ephedra, used by athletes to speed their metabolism, and creatine, taken to build muscle mass, interfere with the body's ability to regulate body temperature and "diminish the ability to sweat."

The report, published in the journal Neurosurgery, reveals that four football players died of heat stroke last year alone. From 1985 to 1994, however, only six deaths related to dehydration and heat stroke were recorded. In 1994, with the passage of the Federal Dietary Supplement Health and Education Act, dietary ingredients used in dietary supplements were no longer subject to the pre-market safety evaluations required of other new food ingredients.

The study indicates that over 70 percent of college athletes and between 30 and 50 percent of high school athletes take performance-enhancing supplements.