The device, called the Glove and invented by two Stanford biologists, is used by the Niners during games and at practice for players’ health. But its applications are far broader: from treating stroke and heart attack victims to allowing soldiers to remain in the field longer under intense heat.

It’s also a proven athletic performance enhancer - billed as better than steroids without any ill effects.

“We use the Glove primarily for health reasons,” said Dan Garza, the 49ers’ medical director. “But outside of sports, it has potential for a lot of exciting things. This technology is a much more effective way of cooling the core temperature than what we would typically do - misting, fanning, cold towels, fluids.”

The Glove works by cooling the body from inside out, rather than conventional approaches that cool from outside in. The device creates an airtight seal around the wrist, pulls blood into the palm of the hand and cools it before returning it to the heart and to overheated muscles and organs. The palm is the ideal place for rapid cooling because blood flow increases to the hands (and feet and face) as body temperature rises.

“These are natural mammalian radiators,” said Dennis Grahn, who invented the device with Stanford colleague Craig Heller.