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Friday, 7 July, 2000, 11:36 GMT 12:36 UK
The health risks of a heat wave
Over exposure to the sun can be dangerous
Prolonged exposure to high temperatures can lead to heat exhaustion and eventually to heatstroke.

Vulnerable people can begin to suffer problems when the temperature rises into the thirties. By the time the thermometer tops 40C, everybody is potentially at risk.

Heat exhaustion refers to overheating of the body due to excessive loss of water or, in rare cases, salt depletion.

People who suffer from heat exhaustion have often been taking part in strenuous physical exercise.

Symptoms include thirst, headache, pallor, dizziness and possibly nausea or vomiting.

In severe cases, the heart may race and the sufferer may feel disoriented.

Heatstroke or sunstroke occurs when the body's thermoregulatory system stops working and body temperature rises to approximately 41C.

Many of the symptoms are the same as for heat exhaustion.

Other symptoms may include:

  • cessation of sweating
  • difficulty walking
  • disorientation
  • fainting or unconsciousness
Heat exhaustion is not fatal, but heatstroke can be.

Other potential problems of over-exposure to the sun include:

  • sunburn - redness and pain in the skin. In severe cases there is also swelling, blisters, fever, and headaches
  • heat cramps - heavy sweating and painful spasms usually in the leg or abdomen muscles

Who is most at risk?

The sun can have a powerful effect on body function

Dr Ron Behrens, of the Hospital for Tropical Diseases in London, told BBC News Online that the elderly and the very young were particularly vulnerable to the effect of high temperatures.

He said obese people, and those with medical conditions such as heart disease and diabetes were also potentially at risk.

He said: "In a heatwave the body has to spend much of its energy trying to keep the core temperature down and this increases the stress on everything else."

However, he said anybody could be at risk if they did not take sensible steps.

"The body needs to adapt to heat, and most of the European population is not heat adapted. The body loses a significant volume of water in respiration and sweat in high temperatures, and maintaining sufficient fluid intake can be quite a problem."

Dr Behrens said another potential problem was the difficulty in storing food in a heatwave.

This could lead to outbreaks of food poisoning and diarrhoearal illnesses, which could further dehydrate the body, and exacerbated the symptoms of heat exhaustion.

How to avoid problems in a heatwave

There are a number of sensible things that everybody should do to avoid illness when temperatures soar.

  • increase your intake of non-alcoholic, non-carbonated, caffeine free beverages such as water and fruit juice
  • wear clothing that is light in colour and loose fitting
  • avoid the outdoors during extreme heat
  • stay out of the sun
  • stay in an air-conditioned environment if possible
  • eliminate strenuous activity
Some experts also believe it is a good idea to cut down on the amount of proteins that you eat during a heatwave, as they can increase metabolic activity and generate heat in the body.


The first thing to do if suffering from heat exhaustion is to get out of the sun, and preferably into an air-conditioned building.

Drink water or, better still, a sports beverage, taking it slowly rather than gulping it down.

If the sufferer does not feel better within 30 minutes, seek medical advice.

It is important to bring down the body temperature of somebody suffering from heatstroke.

This can be done by splashing water on the skin, or by using ice.

If the person is conscious, they should be given plenty of fluids - up to four pints.

See also:

06 Jul 00 | Europe
Dozens die in Balkan heatwave
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