Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Steven Doerr, MD, is a U.S. board-certified Emergency Medicine Physician. Dr. Doerr received his undergraduate degree in Spanish from the University of Colorado at Boulder. He graduated with his Medical Degree from the University Of Colorado Health Sciences Center in Denver, Colorado in 1998 and completed his residency training in Emergency Medicine from Denver Health Medical Center in Denver, Colorado in 2002, where he also served as Chief Resident.
Heat exhaustion is a condition marked by exhaustion that occurs when the body
overheats. The person may feel extremely fatigued and may halt all activity. It
is an emergency condition that if left untreated, can sometimes lead to heat
stroke, a potentially life-threatening condition. This article will focus only
on heat exhaustion, which is on the spectrum of heat-related illnesses along
with heat cramps (which is less severe) and heat stroke (which is more severe).
The main cause of heat exhaustion is failure of the body's cooling mechanism
(mainly evaporative sweating) to maintain a normal core temperature, resulting
in the body overheating. Causes that can contribute to heat exhaustion include
strenuous work or exercise in a warm or hot environment,
intake, and wearing clothing that inhibits evaporative cooling of the body. The
elderly and children under 5 years of age are at higher risk for developing heat
The body can lose significant amounts of water when it tries to cool itself by sweating. Whether the body is hot because of the environment (for example, working in a warm environment), intense exercising in a hot environment, or because a fever is present due to an infection; the body uses a significant amount of water in the form of sweat to cool itself. Depending upon weather conditions, a brisk walk will generate up to 16 ounces of sweat (one pound of water).