Heatstroke

by Dr Rob Hicks

BBC Health,As summer temperatures soar, older people, babies and young children are at greater risk of heat exhaustion, which left untreated can result in heatstroke.

Heat exhaustion
People sweat a lot in hot weather or during exercise. If the body loses too much liquid or salt, the result is heat exhaustion. The body cools itself down by directing blood to the skin and by sweating. Everyone sweats; most people lose more than a litre of sweat a day.

The symptoms of heat exhaustion include:

* Excess sweating
* Nausea and vomiting
* Feeling light-headed/faint
* Tiredness
* Headache
* Muscle cramps


Fortunately, heat exhaustion rarely causes problems and can be treated relatively easily. This is achieved by removing the affected person from the situation causing the problem and by replacing the lost fluids and salt.

Someone affected by heat exhaustion needs to:

* Rest in a cool place - an air-conditioned room is ideal
* Sip cool and salty drinks


They should keep doing this until they feel better.

Heatstroke

If someone with heat exhaustion continues to be exposed to heat, the more serious and life-threatening condition of heatstroke may develop.

In this situation, the body's cooling mechanisms malfunction and are no longer able to assist the body in losing enough heat. The temperature of the body rises and the following symptoms may occur:

* Confusion
* Disorientation
* Rapid and shallow breathing
* Fits

Heatstroke is a medical emergency. If left untreated, an affected person may slip into a coma, often within minutes. Tragically, some people die from heatstroke as a result of heart failure, kidney failure or brain damage caused by the excess body heat.

Anyone believed to be suffering from heatstroke should be admitted to hospital as an emergency. They will usually be cared for in an intensive care unit where their body temperature will be lowered to a safe level and the abnormal salt and water content in the body corrected.
Who's at risk?

Everyone's at risk of heat exhaustion and heatstroke, although some people are more at risk than others. These include:

* Small babies, children and older people, who have less efficient body cooling systems.
* People suffering from diarrhoea, who are more likely to become dehydrated.
* People from cooler climates who travel to hotter climates, as it may take a while for their bodies to get used to the heat. Being in areas of high humidity also increases a person's risk, as this reduces the efficiency of sweating and decreases the amount of heat lost from the body.
* People with certain medical conditions that reduce the efficiency of the body's cooling mechanisms. For example diabetes, obesity and chronic heart failure.
* Those who drink excessive amounts of alcohol, which dehydrates the body.


How can it be prevented?

Avoiding getting into difficulties with heat exhaustion and heatstroke is straightforward:

* Stay in the shade as much as possible
* Drink lots of water
* Avoid alcohol
* Take it easy on hot days - don't overexert yourself


This article was last medically reviewed by Dr Rob Hicks in January 2007.

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