The Centers for Disease Control and Prevention suggests that of all the heat-related illnesses that could occur, heat stroke is the most serious. It is a condition that occurs when the body's temperature is higher than normal. When body temperature is high, sweat is secreted for temperature reduction. In heat stroke, there is a rapid increase in body temperature and not enough sweat production to cool the body down. Heat stroke requires prompt medical attention and can be caused by several factors.
Exertion
Strenuous exercise or activity causes increased heat production in the body. "Irwin And Rippe's Intensive Care Medicine" says that the body produces 300 to 900 kcal per hour of heat during exertion. At this time, even when the environment is optimal for sweat evaporation; such as wearing minimal clothing, only about 500 to 600 kcal per hour of heat is lost. Increased heat production during exertion may lead to heat stroke even in healthy individuals. This type of heat stroke is called exertional heat stroke.
Environmental Temperatures
According to the Mayo Clinic, exposure to high environmental temperatures can cause an increase in body temperature and lead to heat stroke. This type of heat stroke is called non-exertional heat stroke and is more common during warmer and more humid weather.
Medication
Some medications impair the sweating mechanism of the body. A person who cannot sweat is susceptible to heat stroke in the presence of high environmental temperatures. Examples of such medications are anticholinergic drugs, phenothiazines and monoamine oxidase inhibitors.
Dehydration
The body loses water through sweat, urine, tears and stool under normal circumstances. Water can also leave the body as a result of vomiting, diarrhea and excessive sun exposure. Dehydration occurs when the body loses excessive amounts of water and essential salts needed for normal body functions. During dehydration, the body ceases to sweat and blood supply to the skin is reduced. This impairs the body's ability to get rid of heat and may lead to an increase in body temperature or heat stroke.
Aging
According to "Refresher: Emergency Care and Transportation of the Sick and Injured", the aged have an impaired ability to adjust to increasing temperatures in the environment. The elderly cannot sweat effectively and because of this, when there is an increase in temperature there is no corresponding cooling effect from sweat production and evaporation. Heat stroke may occur due to the inability of the aging body to disperse heat. Other factors that put the elderly at risk for heat stroke are as follows: the inability to move and take precautions against heat due to debilitating illnesses; use of certain medications that affect temperature regulation; and chronic diseases that make the body more susceptible to heat stroke.
References
- Mayoclinic: Heatstroke - Causes
- University of Maryland Medical Center: Dehydration and Heat Stroke
- "Refresher: Emergency Care and Transportation of the Sick and Injured"; Andrew N. Pollak, American Academy of Orthopaedic Surgeons; 2000
- "Irwin and Rippe's intensive care medicine"; Richard S. Irwin, James M. Rippe; 2008
- Centers for Disease Control and Prevention: Frequently Asked Questions (FAQ) About Extreme Heat
