Performing in extreme environments

Humans have evolved to live within narrow thermal limits and within a constricted altitude range, yet within these limits human physiology is remarkably adaptable. Athletic competition in extreme environmental conditions is now becoming common, with an ever-growing list of extreme challenges to complement the established classics such as climbing Everest, the Marathon des Sables, swimming the English Channel, the Badwater Ultramarathon, Greenland’s Arctic Circle ski race and the Kona Ironman Triathlon. Heat is generated as a by-product of metabolic processes by the living human body. The aim of pre-cooling is to increase the heat storage capacity of the body, thus reducing heat strain and improving performance in a hot environment. The concept of a ‘holding camp’ has become normal practice in order to acclimatise to the local environmental conditions ahead of competition. Acclimatisation to heat can be achieved by arriving in the target environment 1 week or more in advance of the event.