Over the years, researchers at the Gatorade Sports Science Institute (GSSI) have tested hundreds of elite and recreational athletes to better understand hydration. A few months back they stepped on court to analyze the sweat of the world's fifth ranked women's tennis player, Maria Sharapova. Tiger Woods went through a similar regimen in creating his own custom Gatorade formula, with fancy flavors set to launch this month. Ongoing tests on NFL and NHL players offer similar personalized suggestions on what to drink and when. To dig deeper into the science of sweat, and the perspiration habits of the lovely Ms. Sharapova, PopSci spoke with Beth Stover Mooradian, a senior scientist with Gatorade.