Pepsico (owner of Gatorade) lawyers are now composing new warning labels.
Meanwhile from Gatorade's web site:
TOO MUCH OF A GOOD THING CAN BE BAD, EVEN TOO MUCH WATER." -Randy Eichner, M.D.
While most runners and cyclists know the importance of hydrating, some don't realize overhydrating can dangerously lower blood sodium levels-a condition known as hyponatremia.
Hyponatremia seems most common in female and beginning marathoners and triathletes for two reasons, says Randy Eichner, M.D., professor of medicine and team physician at the University of Oklahoma and volunteer physician at the Hawaii Ironman Triathlon. One, they are on the race course for many hours, losing lots of sodium in sweat. Two, they are hypervigilant about staying hydrated. "They drink lots of water in the days before the race, then stop at every fluid station along the course," he says.
"Drinking is important, but the problem is they drink too much water."