As many of us struggle through a very hot summer, we try to stay cool in the most energy-efficient way. This is key not only for our comfort but also for our very survival.
Humans are in a very precarious position when it comes to thermoregulation. We need to maintain our core temperature within a one-degree range of 36.5°-37.5°C or we will die an unpleasant death through either hypothermia or hyperthermia. To further challenge our thermal equilibrium, ambient temperatures outside of our bodies as well as the amount of heat we generate from within (metabolism and organs) can vary wildly. Our bodies are very inefficient machines with only 25 percent of our food going into usable energy (the phosphate bond that generates adenosine triphosphate, or ATP) and the remaining 75 percent discharged as heat. Our sensitive and demanding cores are therefore caught between unpredictable internal and external temperatures. Clearly, human bodies must have some amazing strategies to maintain thermal equilibrium, or we would be extinct.