Cool invention helps tired players bounce back

http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/09/22/BAQU12UC2...

Players for the San Francisco 49ers trotted off the field during Sunday's game against the Detroit Lions and grabbed for the requisite towels and Gatorade. A few went for something else on the bench, slipping their hands into a coffee-pot-like contraption that stops cramping and overheating.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.

Grahn and Heller also found that cooling overheated muscles dramatically improved physical performance, allowing athletes to work out harder and longer, and hold on to their gains.

"We learned that you can actually reverse that muscle fatigue in a short amount of time," Heller said. "And if you cool muscles during rest, you get a much greater recovery than if you rested without cooling."

In the early 1990s, Heller and Grahn first began looking at using controlled heat to halt tremors in patients coming out of anesthesia. When they put their device over the hand and arm of a patient at Stanford Medical Center, "The core temperature went up so fast," Grahn said, "we thought our recording equipment had broken." The tremors stopped.

Once the license for their heating technology was sold by Stanford, they shifted their focus to cooling. The two were interested in exploring therapeutic uses of lowering body temperature, particularly for people with cystic fibrosis and multiple sclerosis. They turned to exercise as a way to build up a person's internal heat load and then worked to figure out how to "pull it out through vascular structures," Grahn said.