Heat is one of the biggest performance drainers. Becoming steadily overheated as you exercise alters many of the processes in your body, such as how efficiently energy is produced. Further, even relatively small changes to your core body temperature can make you sick or worse. Although the human body is good at keeping us cool and safe from harm, athletes and coaches are always looking for an edge in competition, and emergency responders are similarly looking for better ways to treat heat-induced illness.
One such method that is growing in popularity is the use of a cooling vest. Cooling vests are useful for a variety of purposes, such as preventing heat sensitivity in people with multiple sclerosis, but in a recent study in the Journal of Strength and Conditioning, researchers wanted to know how effective a cooling vest would be for athletes.
It’s a simple premise. When you exercise, much of the energy intended to produce movement is wasted as heat. This occurs in pretty much every chemical process in nature, and the human body is no exception. So to cool the body, add a cold vest to an athlete while he or she rests during exercise. The cold will reduce the excess heat, and the athlete will be back in action better than if no vest was used.
The researchers compared athletes wearing the vest for five minutes in the shade to those who just hung out in the shade without a vest for the same amount of time. They looked at a variety of variables, including temperature and perceptions of heat, and they also did a urinalysis.
The results may seem surprising. The group with the cooling vest, which was virtually the temperature of ice, did not experience cooling in their core any more than those who just sat there for the same length of time. There was no difference between some other factors either, like heart rate, perceived exertion during exercise, or thirst. In fact, the only differences between the groups were that the skin where the vest made contact ended up colder and the athletes felt cooler.
Now, since I’m guessing you read this article’s title, there’s more to it than that. For athletes looking for a performance boost, there simply doesn’t seem to be a good reason to use a cooling vest. In fact, when used as a method of preventing heat-induced illnesses, the researchers actually issued a warning. Because the cooling vest reduced the athletes’ perceptions of how hot they were, the researchers hypothesized the athletes could be unaware that their core temperatures, which are unaffected by the cooling vest, might be raising to dangerous highs. This might make heat-induced illness even more likely in athletes using a vest, despite the intention to keep body temperature lower.
In the end, there doesn’t seem to be good reason to use a cooling vest. Sitting in the shade and sipping water worked just as well as doing the same thing while wearing an ice cold vest. With no performance boost and a possible increase in risk of illness, keeping the vest off and using ice baths as a treatment is the best way to go.
1. Michelle A. Cleary, et. al., “Thermoregulatory, Cardiovascular, and Perceptual Responses to Intermittent Cooling during Exercise in a Hot, Humid Outdoor Environment,” Journal of Strength and Conditioning Research DOI: 10.1519/JSC.0b013e3182a20f57.
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