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A research team from the Montana Center for Work Physiology and Exercise Metabolism at the University of Montana traveled to Kona the week before the 2010 Ironman World Championship to put the cooling material Xylitol (a natural sugar alcohol that provides a cooling sensation when wet) to the test. While Montana is not known for its excessive heat, this research team is well versed in studying athletes in extremely hot conditions, including three previous Ironman World Championships and the Badwater Ultramarathon.

To remain cool in a hot environment it is necessary to reduce the amount of heat gained from the environment and maximize the cooling effect of sweat evaporation. Light-colored, high performance race clothing reduces the amount of solar radiation absorbed by the skin, but also reduces the natural ability of the skin to evaporate sweat for cooling. Therefore, many triathletes wear as little, light colored clothing as possible, choosing to deal with the solar radiation in exchange for the ability to evaporate sweat. Recently companies like CEP have developed materials that claim not only to reduce the solar radiation absorbed by the skin (with a 30 UPF), but to also increase the surface area of the skin and increase the potential for sweat evaporation. In addition, CEP is infusing is sleeves with the aforementioned Xylitol substance. But do these arm coolers actually provide enhanced cooling of the skin? If these cooling sleeves work, the athlete will use less energy to cool the working body, and therefore be able to contribute more energy to swimming, cycling, and running. This would result, of course, in faster race times in hot environments.


Research volunteers were outfitted with patches that digitally recorded skin temperature on each forearm, and wore a white CEP Ice-fil sleeve on one arm. The volunteers ran for 30 minutes at their projected Ironman race pace while we recorded the skin temperature of both the sleeved and bare arm. Most volunteers completed the run on a portion of the Ironman race course in the Natural Energy Lab, a location that is renowned for intense heat, humidity, and solar radiation—all the variables that make Kona especially hostile for racing. By the end of the short 30 minute run there was a statistically significant 1.7°C (3.0°F) difference between the skin temperatures of the two arms. The arm with the cooling sleeve was 3.0°F cooler than the bare arm. This cooler skin temperature provides an increased heat gradient between the internal and external environments, thereby increasing the internal heat lost to the environment. While not studied directly, this cooler skin temperature was probably a combination of reduced heat absorption from the sun and accentuated evaporative cooling of the skin.      

While the sleeves were researched during a 30-minute run, one could expect the sleeves to be as effective if not more effective while cycling. This is due to the same reduction in the absorption of solar radiation and an increased evaporative cooling effect with the increased air flow over the body while on the bike.

We found these cooling sleeves to help cool the skin surface while protecting it from the harmful solar radiation. The arm coolers provide athletes an additional tool to combat the hot, humid, and sunny environments so often experienced during training and racing. Along with proper hydration and nutrition, cooling sleeves have the potential to increase race performance. Heading to Abu Dhabi? You might want to invest in a pair of these.