HELP is at hand for exhausted, overheated athletes. A glove-like device promises to reinvigorate them and improve their performance by rapidly cooling their internal organs.
When you鈥檙e working hard, one way your body tries to keep cool is to divert blood from deep inside to vessels just beneath the skin of your palms and the soles of your feet. As the blood is pumped through these vessels, it loses heat through the skin. This prevents your internal organs from becoming dangerously overheated.
But redirecting blood in this way means there鈥檚 less available to carry oxygen to your muscles. And with less oxygen, the muscles are unable to work as hard. Athletes often refer to this energy-sapping effect as 鈥渉itting the wall鈥�.
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Now animal physiologists Craig Heller and Dennis Grahn at Stanford University in California have come up with a device that rapidly cools the body鈥檚 organs. This means blood doesn鈥檛 need to be diverted away from muscles to cool the organs.
The device, called Rapid Thermal Exchange (RTX), consists of a chamber containing a water-cooled steel plate. When an athlete puts their hand in the chamber, a seal forms around their wrist and a pump creates a slight vacuum inside. The vacuum helps increase blood flow to the hand while the steel plate efficiently draws heat from blood circulating through their hand (see Graphic). The cooled blood flows back to the heart and is recirculated, cooling other organs by as much as 3 掳C.
In tests, the device made a big difference to athletes鈥� performance. Eight professional cyclists who used it during a 30-kilometre time trial on stationary bikes mounted on rollers in a lab were on average 6 per cent faster than they were without it. Another group of athletes who used RTX during weight training found that when they cooled themselves between sets of bench presses they could manage around 20 per cent more repetitions.
The device isn鈥檛 only useful for sports where stoppages are frequent, such as football, hockey and track and field events. Runners and cyclists who have to rest or pull out of races due to heat exhaustion could quickly recover using RTX and rejoin the race. Julian Nikolchev, president of Avacore Technologies in Palo Alto, California, which has been licensed to market RTX, says it also has medical applications.
The US Food and Drug Administration has approved its use in hospitals for regulating body temperature. Cooling the bodies of people who have just had a heart attack or stroke, for example, can reduce the amount of damage they sustain. By heating the steel plate in the device鈥檚 chamber, the device can also be used to increase body temperature. This could increase the effectiveness of cancer therapy, says Nikolchev, because cancer cells are more vulnerable to chemotherapy and radiation at higher temperatures.