Ice slush: effects, benefits and evidence

Ice slush, or slurry, is a very low temperature (0-1 °C) drink made with blended ice and liquids. Although popular as ‘slushies’ and available in various bright colours in places like fairs, arcades or cinemas, ice slush is used for its sports nutrition benefits in hot weather sporting settings. We have seen a lot of slush use at the very hot Tokyo Olympic Games and we have seen it in events like the Tour de France. It can be used for pre-cooling before a race or competition, during exercise or breaks and post-race to reduce and maintain core temperature.

A high body temperature is clearly a contributor to fatigue and preventing very high temperatures has been shown to improve performance. This can be done by various ways of pre-cooling and perhaps also by cooling during exercise, although this is much more diffiocult from a practical point of view. In conditions such as those at the Tokyo Olympics with high temperature and little opportunity for evaporative cooling (cooling through sweating) because of the high humidity, cooling the bod using other methods is especially effective.

Photo by Bram Berkien - Jumbo Visma

Effects on physiology

Ice slush can cool an athlete much more and faster than drinking a cold drink. The energy (heat) required to turn ice into fluid is over 80 times as high as the energy required to simply heat up cool water (based on the theory of enthalpy). Therefore, ice slush is a very effective way of reducing body temperature and is a process that occurs inside the body (and does not rely on environmental