A new study in the Journal of Athletic Training has found that wearing cooling neck collars allows athletes to run significantly farther in hot conditions than normal. Researchers from Roehampton University in London theorize that cooling the neck keeps the brain from registering a high core temperature, allowing runners to continue exercising even as they near exhaustion. But because the ice packs affect only the brain's perception of temperature—not the runners' core itself—the practice may subvert a self-protective response and put athletes in danger of heat stroke. Research popularized by South African physiologist Tim Noakes has shown that the body will shut down if core temperatures exceed 104 degrees Fahrenheit, before brain damage or heat stroke set in.
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