Heatstroke

What is heatstroke?

Heat exhaustion is a collection of symptoms brought on as the body struggles to control its temperature. Left untreated, heat exhaustion can progress to a more severe form known as heatstroke.

The body normally uses several mechanisms to cool itself down, including directing more blood to the skin and by sweating. Everyone sweats. Most people lose more than a litre of sweat a day. In hot weather or during exercise, when the muscles generate large amounts of heat, they sweat even more heavily - losing large amounts of water and salts. If the body loses too much liquid or salt, the symptoms of heat exhaustion develop.

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

In this situation, the body becomes dangerously dehydrated. Its cooling mechanisms malfunction and are no longer able to assist the body in losing enough heat, so the body temperature starts to rise.

Heatstroke symptoms

The symptoms of heat exhaustion include:

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

With heatstroke, the temperature of the body rises and the following symptoms may occur:

• Confusion
• Disorientation
• Rapid and shallow breathing
• Fits (seizures)

Causes and risk factors of heatstroke

Anyone can develop 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.

Treatment and recovery from heatstroke

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 - the excess body heat can lead to heart failure, kidney failure or brain damage.

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.

Fortunately, heat exhaustion rarely causes serious 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 salts.

Someone affected by heat exhaustion needs to:

• Rest in a cool place - an air-conditioned room is ideal
• Sip cool drinks - drinks especially designed for rehydration (e.g., electrolyte replacement sports drinks) are useful because they contain a good balance of different salts
• Take a cool shower or bath, soak feet in a bucket of water or place a wet towel on the shoulders

They should keep doing this until they feel better.

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

• Stay in the shade as much as possible
• Drink lots of cool drinks
• Avoid alcohol or caffeine which are dehydrating
• Take it easy on hot days - don't overexert yourself