Above air temperatures of 95 degrees, virtually all the body s cooling is done through perspiration. Sweat on the skin can evaporate so quickly, many people are not even aware they are perspiring. Fluid losses therefore can be rapid and excessive. Even on river trips where there is an abundance of water, people have developed heat exhaustion or heat stroke. Keeping your body cool and hydrated is vital.
Heat is a potentially deadly natural hazard in the Grand Canyon.
It s responsible for more emergency evacuations than all other natural hazards combined. Wear a wide brim hat, and loose fitting clothing that breathes, to keep a layer of humidity against your skin. It s also good idea to cool your body down by frequently wetting your head and clothes. By wetting your body down, you compensate by making artificial perspiration. It feels wonderful when it's extremely hot, especially when you are hiking uphill.