Heat Exhaustion and Heat Stroke Overview
Heat exhaustion: This condition often occurs when people exercise (work or play) in a hot, humid place and body fluids are lost through sweating, causing the body to overheat. The person's temperature may be elevated, but not above 104°F.
Heat stroke: This medical condition is life-threatening. The person's cooling system, which is controlled by the brain, stops working and the internal body temperature rises to the point where brain damage or damage to other internal organs may result (temperature may reach 105+°F).
Heat Exhaustion and Heat Stroke Causes
Heat exhaustion is typically caused when people who are not well adjusted to heat exercise in a hot, humid environment.
•At high temperatures, the body cools itself largely through evaporation of sweat.
•When it is very humid, this mechanism does not work properly.
•The body loses a combination of fluids and salts (electrolytes).
•When this is accompanied by an inadequate replacement of fluids, disturbances in the circulation may result that are similar to a mild form of shock.
Heat stroke may often develop rapidly.
•Medical conditions or medications that impair the body's ability to sweat may predispose people to this problem.
•Heat stroke happens in the following two ways:
◦The classic form occurs in people whose cooling mechanisms are impaired.
◦The exertional form occurs in previously healthy people who are undergoing strenuous activity in a hot environment.
•Infants and the elderly are more likely to have this problem, as are those who are taking antihistamines and certain types of medication for high blood pressure or depression.
Heat Exhaustion and Heat Stroke Symptoms
Heat exhaustion symptoms
•Often pale with cool, moist skin
•Muscle cramps or pains
•Feels faint or dizzy
•May complain of headache, weakness, thirst, and nausea
•Core (rectal) temperature elevated-usually more than 100°F-and the pulse rate increased
Heat stroke symptoms
•Unconscious or has a markedly abnormal mental status (dizziness, confusion, hallucinations, or coma)
•Flushed, hot, and dry skin (although it may be moist initially from previous sweating or from attempts to cool the person with water)
•May have slightly elevated blood pressure at first that falls later
•May be hyperventilating
•Rectal (core) temperature of 105°F or more
When to Seek Medical Care
As with all other medical problems, a doctor should be called if you are not sure what is wrong, if you do not know what to do for the problem, or if the person is not responding to what you are doing for them.
•Call a doctor for heat exhaustion if the person is unable to keep fluids down or if their mental status begins to deteriorate. Symptoms of shortness of breath, chest pain, or abdominal pain may indicate that the heat exhaustion is accompanied by more serious medical problems.
•Suspected heat stroke is a true, life-threatening medical emergency. Call for an ambulance and request information as to what to do until the ambulance arrives. A person with suspected heat stroke should always go to the hospital (or call for an ambulance) at once.
For heat exhaustion, a person should go to the hospital if any of the following are present:
•Loss of consciousness, confusion, or delirium
•Chest or abdominal pain
•Inability to drink fluids
•Temperature more than 104°F
•Temperature that is rising despite attempts to cool the person
•Any person with other serious ongoing medical problems