A 2012 study published in the Journal of Military and Veterans' Health reveals a simple, cost-free way to rapidly lower core body temperature without a fan: consuming slushies made from crushed ice and water. Exercise physiologist Matt Brearly, the study's researcher, found that this method can reduce core temperature by 0.3 to 1.1°C, making it effective for preventing heat exhaustion.
How the Slushie Hack Works
The study recommends drinking a mixture of equal parts crushed ice and water. Unlike sugar-laden commercial slushies, this version uses only ice and water. The mechanism relies on the physics of phase change: ice requires a large amount of energy to melt, absorbing heat from the body in the process. Crushed ice absorbs about three times as much heat as the same volume of cold water, according to the research.
To apply the method, the study suggests consuming five to seven grams of crushed ice per kilogram of body weight. This should be done slowly, approximately 30 minutes before outdoor activity or exercise. The cooling effect can last for the duration of the activity.
Effectiveness in Extreme Heat
The UK is bracing for a heatwave with forecasts of 41°C next Tuesday, potentially surpassing the record 40.3°C set in July 2022. In such conditions, staying cool is challenging, but this military-tested hack offers a practical solution. The study notes that while the method was developed for military use, it is equally applicable to civilians, especially those working outdoors or exercising in hot weather.
Important Caveats
The slushie hack is not a substitute for hydration. The study emphasizes that it does not replace drinking water. In hot weather, it is crucial to continue drinking water throughout the day to replenish fluids lost through sweat. The crushed ice slushie should be used as a supplementary cooling measure, not as the sole source of fluid intake.
