Simon Lowden, chief marketing officer of PepsiCo International, said: "This partnership is mutually beneficial for Gatorade and Chelsea.
"Not only does Chelsea understand the important role that Gatorade plays in keeping athletes performing at their peak, we are able to utilise yet another elite platform to develop our scientific research."
Scientists from the Gatorade Sports Science Institute performed sweat tests with the team during their pre-season tour in the US and the results from these tests will be used to optimise the hydration of the Chelsea players both as a group and individually.
The GSSI will be working with the club to educate elite and amateur athletes, sports health professionals and youth on the importance of proper hydration.
Peter Kenyon, Chelsea chief executive, said: "This partnership means much more than working with a great brand. Gatorade is backed by a 40-year history of scientific research that puts it at the forefront of performance, which is where Chelsea want to be."