From science to practice: Development of a thermally-insulated ice slushy dispensing bottle that helps athletes “keep their cool” in hot temperatures

Abstract

Like many of us, I love sport. I care deeply about athlete performance. It is my job to. That passion has enabled me to wear a number of hats in the arena. I’ve been an athlete (triathlon and cycling), a coach, a professor, and an applied sport scientist. Residing in this sometimes messy, often fun, middle-space, between research, theory and application, which do not always align, I’ve been able to make some observations, identify some problems, and foster some solutions. The topic of this editorial is a story about how I’ve assisted to bridge a small gap between science and practice, by mixing scientific understanding and ingenuity to alter athlete temperature. Last year I delivered two presentations in Paris on this topic, entitled: Keeping your cool: How fluid temperature affects thermal comfort and performance in the heat. My opening slide included the picture, shown as Figure 1. Here we have two of today’s world-best triathletes, Andrea Hewitt and Rachel Klamer, racing in the Gold Coast World Series Race in Australia (April 2015). In this race, it was 28 Celsius, with high humidity. To me, this picture speaks volumes about what’s really important when maximizing performance in hot environments. Consider the following question: what’s essential to these athletes when they have cold fluid in their hands? Are they thirsty and dehydrated, or is it more likely that their brain/body is overheating? If these athletes were thirsty, and fluid consumption mattered to their brain at that point, then surely they would be more interested in drinking that fluid; but clearly they are not. When it’s on, with metabolic heat production sky high, (as it is in most of the Olympic sports we deal with) it’s brain temperature, or perhaps more accurately the brain’s recognition of a body that’s overheating that matters. So let’s go back in time a bit and allow me to tell you the story about how I became involved in discovering the importance of fluid temperature for performance in the heat. While employed as a lecturer at Edith Cowen University (ECU) in Perth Australia, I enjoyed collaborating with Dr David Martin, an Australian Institute of Sport Senior Physiologist, in the area of precooling athletes before competition in the heat in order to improve performance. It was 2006, and the Beijing Olympics were at the forefront of our minds. We’d put our heads together previously for the Athens’ Games strategy where we had arrived at the position that the best precooling strategy possible, was a combining a plunge pool maneuver with an ice jacket to retain body coolness. Beijing, expected to be just as hot, was up next, and we were still searching for something effective and practical to keep athletes cool. Meanwhile, a sport scientist up in Darwin, named Matt Brearly, was doing some experimentation during his bike rides. Of course, it doesn’t get much hotter in Australia than this place. Very simply, he was looking at what happened to his performance times riding home from work when he drank cold fluids vs. ice slushy. Ice slushy is the mix of solid ice particles and a bit of glucose to serve as an antifreeze, inside a water medium to form a slurry. Matt was finding a big difference to his performance times in the heat, going much faster when he drank the ice slushy before his ride. Now why would that be? To understand, we need to dig deeper. With phase change, any energy required to reconfigure a substance from a solid to a liquid water gets transferred from the area of concern. In a person ingesting the ice slushy, that’s the person themself. So in theory, even if the substances were at the same temperature (0 C), the solid