Studies have shown that ethanol–which is a kind of alcohol–causes skin cells to put out the same neurochemical signals they put out when heat is around. The result is that it doesn’t take as much actual heat for the VR1′s to turn on.
Olympic trainers take these systems into account. A long-distance runner should use aerobic metabolism for as much of her ATP as possible. To ensure this, she’ll be tested on a treadmill to measure her threshold of aerobic metabolism.