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Dehydration and Heat Exhaustion

by Patty de Urioste, MD

As printed in Around Town Publishing, June 2006

Now that we are deep into summer, an important health consideration is how to deal with the extreme heat that we encounter here, especially in July and August. Many people are unaware that excessive heat can be dangerous. However, the CDC reports that from 1979-2002 there were 8,966 deaths in the United States due to excessive heat exposure.

Normally the body has several ways to insure that overheating does not occur. Sweating is one of the major defenses used to keep us cool. This works pretty well unless the temperature or humidity gets too high, our physical conditioning is not sufficient, we over exert ourselves, or are in a high risk group for heat stress.

Anyone can suffer from heat exhaustion or heat stroke, but those especially at high risk include infants and children up to 4 years old, individuals 65 years old or older, those who are overweight, physically ill or on certain medications, and persons who overexert themselves during work or exercise.

Infants and children depend on others to provide sufficient liquid intake and regulate their environment. Those who are 65 or older are less able to tolerate excessive heat and are not as likely to sense extremes in temperature. When someone is overweight an increased core body temperature cannot be efficiently lowered because of extra insulation from the adipose tissue. Certain types of medication that are commonly taken can interfere with our body’s ability to dispense heat when it gets too hot outside. If you are on any medicine–either prescription or over-the-counter–it is important to check with your doctor or pharmacist to determine if they would put you at risk for heat-related illness. Some common medications are antihistamines, antidepressants, certain stimulants, cardiovascular medications (including some that are used to control blood pressure), certain thyroid drugs, laxatives, and alcohol. Remember not to discontinue any medicine unless your doctor advises it!

When a person is exposed to temperatures that are in the 80s and above it is important to observe some general rules: 1) Dress in cool, loose, light-colored clothing and shade your face. 2) Limit sun exposure during the hottest part of the day. 3) Drink plenty of fluids, including water, and replace your body’s salt using a sports electrolyte drink. 16-32 ounces per hour of cool fluids for adults helps compensate for extreme temperatures and avoid dehydration. Do not drink alcoholic beverages as they will actually cause you to lose more fluid. 4) High risk individuals should plan to stay indoors in an air-conditioned place. 5) Avoid eating heavy meals and hot foods. 6) Never leave anyone in a hot car. 6) Try to rest often in shady places. Using a fan can be helpful, but it is not effective over about 90 degrees. 7) Do not take salt tablets.

Know the danger signs of overheating to help avoid serious consequences. These include weakness, dizziness, fainting, confusion, paleness, heavy sweating (or in extreme cases, no sweating with hot, dry skin), nausea or vomiting, muscle cramps or headache.

If you or someone else develop symptoms of heat stress here’s what to do: 1) get the person to a shady location, 2) cool him or her rapidly by wetting the skin with cool water and fanning, 3) you can give the person a half glass of cool water every 15 minutes, but do not allow him or her to drink too rapidly. Do not give liquids with alcohol or caffeine as they can make the condition worse, 4) call for emergency help.

We all love summer and the outdoor activities associated with it. Following these guidelines can insure a safe, fun summer for everyone!