In 1965, Cade was approached by Dewayne Douglas, an assistant coach for the Florida Gators football team, about the extreme dehydration faced by Gator football players practicing in the high temperatures and humidity of the Deep South in late summer and early fall. Douglas questioned Cade why his football players did not urinate during practice and games. Cade learned from anecdotal evidence that football players were losing water through perspiration and failing to replace fluid during practice and games. Cade's research team discovered that football players were losing up to 18 pounds (8.2 kilograms) during the three hours of a college football game, and that ninety to ninety-five percent of that loss was water. A player's plasma volume could decrease as much as seven percent and blood volume by five percent, and sodium and chloride were excreted in the sweat.
During 1965 and 1966, Cade, together with his team of research doctors Dana Shires, James Free, and Alejandro M. de Quesada, conducted a series of trial-and-error experiments with his glucose-and-electrolytes rehydration drink on members of the Gators football team of coach Ray Graves, first with members of the freshman squad, and after initially promising results, with starting members of the varsity team. "It didn't taste like Gatorade," Cade said in a 1988 interview with Florida Trend magazine. In fact, according to Cade, when Gators lineman Larry Gagner first tried it, he spat it out and strongly suggested that the original experimental formula tasted more like bodily waste. Dana Shires remembered that "it sort of tasted like toilet bowl cleaner." To make it more palatable, at the suggestion of Cade's wife, the researchers added lemon juice and cyclamate to the original formula of water, salt, sodium citrate, fructose and monopotassium phosphate.
Gatorade, now owned by PepsiCo, is today sold in some eighty countries and over fifty various flavors. In contrast to the forty-three dollars that Cade and his team spent to make the first experimental batch of Gatorade in 1965, Gatorade prompted the evolution of a multibillion-dollar sports drink industry in the years that followed; as of 2007, over seven billion bottles of Gatorade were being sold annually in the United States. While he was surprised by its commercial success as a sports drink, Cade took greater pride in Gatorade's use in hospitals, in post-operative recovery and to treat diarrhea-related dehydration in infants and young children. Cade's other research included hypertension, exercise physiology, autism, schizophrenia and kidney disease. His research into carbo-loading substantiated the early claims of Swedish researchers, and he also invented a hydraulic football helmet that substantially reduced the risk of concussion to football players.