1. Archive


Excessive exposure to heat can be harmful to even the most fit among us. Study up on safety.

I love the sun. Unfortunately, between my age, my heart medications and recurring skin cancers, the sun and I do not get along.

In June, after slathering myself with sunblock, I spent the afternoon by the pool, reading and swimming. After a while, I moved to a shaded hammock. Feeling drowsy, warm and pleasantly sweaty, I quickly fell asleep.

Upon awakening, I struggled to get off the hammock. As soon as I stood up, I became dizzy and fell onto the concrete steps. I was sheepish, full of aches and bruised all over, but fortunately, I did not break a bone.

As a physician, I should have known better. The summer heat can be overwhelming, and dizziness upon standing is common for many. This is caused by a drop in blood pressure, the result of a condition called orthostatic hypotension.

When heat-related, the cause of the drop in blood pressure is twofold. First, upon exposure to heat, blood vessels in the skin dilate, which can lead to a drop in blood pressure. At the same time, profuse sweating causes fluid loss and leads to dehydration. Standing up suddenly can be dangerous.

In older people, exposure to heat and a resultant fall can be fatal. More people die of falls and fractures than from breast, colon and lung cancer combined. The risk of developing heat-related drops in blood pressure is made much worse if a person takes blood pressure medications.

Also, for elderly people, dehydration often does not lead to an increase in thirst. This lack of fluids can result in confusion and disorientation, and it can result in a coma. The body temperature becomes quite high, the skin is red and hot, and the ability to sweat is lost. If not rapidly treated, this condition often proves fatal.

Getting to an emergency room quickly is critical. Gradually bringing the body temperature to normal and giving intravenous fluids can be lifesaving.

During the summer we all should take precautions to prevent excessive exposure to heat. A drop in blood pressure is an early sign, but more serious problems may develop. Exercising in the heat of the day can be dangerous for anyone.

A common complication of activity and sweating is severe cramps in the arms, legs or abdomen that often make continued exertion impossible.

A more serious problem is heat exhaustion, which is caused by prolonged exposure and develops more quickly in those working outdoors or exercising. Symptoms include sweating, fatigue, dizziness, muscle cramps, nausea and headache.

The most serious complication is heatstroke, which occurs when the body is no longer able to maintain a normal temperature. Body temperature can rise as high as 106 degrees. This usually occurs in individuals who work for long hours outdoors or in the very old who do not have air conditioning and are indoors during extreme heat waves.

Be wary any time there is a heat advisory or the heat index reaches above 100 degrees. Seek shade and drink plenty of fluids. Be particularly careful if you are taking blood pressure medications.

Gerontologist David Lipschitz is the author of "Breaking the Rules of Aging." Write him at

Fast facts

Liquid measures

- About 60 percent of our body weight is the water that is the main component of both blood and cells.

- Having too little water is termed dehydration.

- Sudden dehydration, described by Dr. David Lipschitz, occurs when the body shifts too much water from blood to the skin. That results in falling blood pressure.

- To avoid sudden dehydration, avoid too much time, and exertion, in the sun. Drink the equivalent of 2.5 to 3 quarts (80-96 ounces) of water every day.

Source: The Merck Manual of Health & Aging