CHILLING OUT
RAPIDLY COOLING YOUR CORE— WITH A MITT, OF ALL THINGS— CAN IMPROVE WORKOUTS
IT RESEMBLED an eighth- grade science project, an oversized oven mitt tethered to a lunch box– like cooler. Not exactly high tech. But nonetheless, Stanford biology researcher Dennis Grahn made a bold claim about the cutting-edge device he had developed with biology professor Craig Heller in 2012: “Equal to or substantially better than steroids… and it’s not illegal.”
When worn on the hands, the glove- like gadget promised to quickly cool an athlete’s core temperature, thus improving exercise strength and slowing fatigue during training, which could ultimately lead to performance boost during competition.
It’s taken years for Grahn’s and Heller’s research to go mainstream.
The first licensee of the cooling technology, medical device startup Avacore Technologies, did not have adequate resources, Heller says, and the original design was “cumbersome, expensive and fragile.” Since then, Arteria Technology has produced and commercialized a superior, less expensive device—the Coolmitt is now used by athletes in nearly every major sports league, the military and first responders. Other companies have also exploited the palm-cooling concept into other forms beyond the glove, such as rods and graspable bars.
Why the palms? It all started with bears.
In their research on heat dissipation, Grahn and Heller discovered that during warmer weather, thick-furred and fat-covered black bears are able to avoid overheating because of hairless body parts (on the pads of the feet and tip of the nose) that contain a network of veins specifically designed to expedite heat loss.
Humans also have these surfaces— on the soles of the feet, face, ears and, most prominently, the palms.
When you exercise, heat builds up and raises the temperature of the muscle fibers. In order to prevent damage, the body has a builtin system that slows the muscle’s activity to cool it down—that’s the feeling of fatigue and failure you experience during training.
Because the palms contain those special blood vessels, called AVAS, or arteriovenous anastomoses, they can release heat more quickly and more efficiently than any other part of the body. When a device circulates water on the palms, it cools the blood, which is sent to the heart and then pumped back into the overheating muscles.
“If you put cold compresses on your arms, for example, it’s going to take a lot of time for that cooling capacity to reach the working muscles,” Heller says. “The advantage of these palmar heat exchange devices is that you end up cooling the muscles from the inside out.”
Heller says the biggest challenges with the in-competition application of the research are convenience, wearability and portability. (He notes the devices are better suited for training.) Sports that feature frequent timeouts or pauses in play, such as basketball or tennis, make palm cooling more available to athletes. But Heller notes that in football, for example, many players tape their hands, which makes the palms inaccessible during a game.
It’s not quite steroids, but if you’re looking for a workout supplement, it’s pretty cool.