Summer Heat — A Dangerous Health Risk

By Mark A. Kelley, MD |08/15/16

Weather cross the U.S. has been unusually extreme this summer. Most regions have experienced high temperatures, often accompanied by high humidity. Summer heat can be a serious health hazard. This is why weather forecasters issue “heat alerts”, warning people to stay in cool environments.

Historically, heat waves have caused many deaths, especially among the elderly. Heat-related illness has also claimed the lives of younger victims, such as athletes and military trainees. These tragedies are preventable.

Our bodies are vulnerable to heat or cold. Major organs, blood flow and biochemical mechanisms only work within a narrow range of internal body temperature.

The human body can make some adjustments to outside temperature change. When it is cold, blood flow shifts away from our limbs to internal organs to preserve heat.  This is why our hands and feet feel cold.

In hot weather, our bodies do the opposite. We cool off by shifting more blood flow to our skin while producing sweat. When sweat evaporates, it acts like a natural sprinkler system and pulls heat away from the skin. . The extra blood flow to the skin speeds up the cooling process by moving “hot blood” from inside the body to the cooler surface of the skin.

This works well except when the environment is unusually hot and humid.

In that situation, sweat does not evaporate because of the high humidity. This blocks the body’s best method to eliminate body heat, and can lead to high internal body temperatures.

There are two stages of heat-related illness … and both have warning signs.

In the first stage called “heat exhaustion” the patient sweats profusely with cold clammy skin and may feel faint or nauseous. If this continues, the result can be dehydration and failure to sweat. Without any sweat, body temperature can climb quickly.

This can lead to the second and most dangerous stage, called “heat stroke”. The victim becomes confused and may have seizures or trouble walking. If left untreated, heat stroke can result in major organ failure and death. Heat stroke is an emergency that requires immediate medical treatment.

These serious conditions can be prevented. The concept is simple–-avoid environments that raise body heat and keep well hydrated. Here are some tips:

1. Avoid the high heat and humidity by staying out of the sun and seeking cool, well-ventilated, preferably air-conditioned spaces. This will keep your body heat down.

2. Avoid vigorous outdoor exercise in extreme heat. Exercise in these conditions is risky. It quickly raises body heat while the hot, humid air prevents cooling and promotes dehydration. If you must exercise outdoors, choose times early or late in the day when the temperature is lower. This is the strategy used by high performance athletes.

3. Take special precautions if you are elderly or live in an apartment. The elderly are particularly sensitive to extreme heat. During heat waves, apartments and other closed dwellings can become dangerously hot if they do not have fans or air conditioning. In these situations, it is wise to seek temporary shelter in a cooler place, either with friends or relatives or in cooling shelters provided by municipalities.

4. Drink lots of fluids whether or not you are thirsty. Staying hydrated helps your body cope with the heat.

With these sensible approaches, you can safely ride out the heat wave and look forward to cooler days.

For excellent recommendations on prevention, recognition and treatment of heat exhaustion and heat stroke, see the Centers for Disease Control website.

For more detailed information about the hot weather and health, see E-medicine.

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