Heat stroke occurs when a person becomes dehydrated and their body temperature rises above 40.5C. This is a medical emergency and can lead to death. If you are organising a large event or sports activity, working in a hot environment or fire fighting, you should develop a heat stroke prevention plan.
Heat stress occurs when the body becomes dehydrated and is unable to cool itself enough to maintain a healthy temperature. If left untreated, this can lead to heat stroke, which is a life-threatening medical emergency.
Prevention is the best way to avoid heat stroke.
People most at risk of heat stroke
Anyone can suffer from heat stroke, but those most at risk are:
- People over 65 years, particularly those living alone or without air conditioning
- Babies and young children
- Pregnant and nursing mothers
- People who have existing medical conditions, especially with heart disease, high blood pressure or lung disease
- People on medications for mental illness.
Heat stroke can cause organ damage or death
Heat stroke occurs when the core body temperature rises above 40.5C and the body’s internal systems start to shut down. Normally, sweating helps to maintain a healthy body temperature by increasing heat loss through evaporation. When a person becomes dehydrated, they do not sweat as much, their blood becomes concentrated and organ functioning is impaired.
Many organs in the body can suffer tissue damage and the body temperature must be reduced quickly. Most people will have profound central nervous system changes such as delirium, coma and seizures. As well as effects on the nervous system, there can be liver, kidney, muscle and heart damage.
Causes of heat stress
People attending large events (concerts, dance parties or sporting events), working in hot and poorly ventilated or confined areas, or engaging in vigorous physical activity in hot weather are at increased risk of dehydration and heat stroke. Exposure to radiant heat from bushfires can cause rapid dehydration and heat-related illness. Bushfires usually occur on days of high temperature, which adds to the risk.
Some drugs, such as ecstasy and speed, also raise the body’s temperature, while alcohol dehydrates the body.
Symptoms of heat stroke
Heat stroke may appear similar to heat exhaustion, but the skin may be dry with no sweating and the person’s mental condition worsens. They may stagger, appear confused, fit, collapse and become unconscious.
Warning signs of heat stroke vary, but may include:
- Very high body temperature
- Red, hot, dry skin (no sweating)
- Dry swollen tongue
- Rapid pulse
- Throbbing headache
- Dizziness, confusion, nausea
- Eventual unconsciousness.
Preventing heat stroke
Suggestions for preventing heat stroke include:
- Drink plenty of water or other cool, non-alcoholic fluids. (Check with your doctor if you are on limited fluids or fluid pills.) Avoid drinking extremely cold liquids as they can cause stomach cramps.
- Avoid heavy exertion. Reduce physical activity and avoid vigorous exercise in hot weather. If activity is unavoidable, try to schedule activity for the cooler part of the day and rest often. Whenever possible, stay indoors or in the shade.
- Stay cool and keep air circulating around you. Use air conditioning if possible. If you don’t have air conditioning, consider visiting an air-conditioned shopping centre or public library.
- Eat regular, light meals.
- Wear lightweight clothing.
- Take a cool shower, bath or sponge bath.
- Check on older, sick and frail people who may need help coping with the heat.
- Never leave anyone or pets in a closed parked car.
- Limit outdoor activity to the coolest part of the day.
- Protect yourself from the sun and ‘slip, slop, slap’ when outside by covering exposed skin, using sunscreen and wearing a hat. ‘Seek’ shade and ‘slide’ on some sunglasses.
- Rest regularly in the shade and drink fluids frequently.
Managing events or workplaces
If you are organising a large event or sports activity, managing workers in a hot environment or engaged in fire fighting:
- Develop and follow a heat stroke prevention plan.
- Don’t rely on fans to cool people, unless there is adequate ventilation.
- Know the signs and symptoms of heat stroke and know how to respond.
- If drinks are confiscated from patrons at the entrances to large events (for security reasons), ensure there is plenty of free water available and easily accessible.
Heat stroke is a medical emergency
Every minute’s delay in cooling a person with heat stroke increases the likelihood of permanent injury or death. Apply first aid and seek medical assistance immediately if you, or someone you are with, shows any sign of heat exhaustion or heat stroke.
For more first aid information, visit the St John Ambulance Australia website.
What to do for heat stroke
If someone you are with develops heat stroke:
- Call triple zero (000) for an ambulance.
- While waiting for emergency medical help, get the person to a cool shady area and lay them down.
- Remove excess clothing and wet their skin with water or wrap in wet cloths, fanning continuously.
- Do not give the person fluids to drink.
- Position an unconscious person on their side and clear their airway.
- Monitor their body temperature where possible and continue cooling efforts until the body temperature drops below 38°C.
- Wait for the ambulance to urgently transport the person to hospital, where more intensive cooling and support can be given.
- If medical attention is delayed, seek further instructions from ambulance or hospital emergency staff.
Where to get help
- In an emergency, call triple zero (000)
- Emergency department of your nearest hospital
- Your doctor
- NURSE-ON-CALL Tel. 1300 60 60 24 – for expert health information and advice (24 hours, 7 days)
- Maternal and Child Health Line, Victoria (24 hours) Tel. 132 229
- St John Ambulance Australia website
Things to remember
- Heat stroke is a life-threatening emergency that can be avoided by following simple prevention measures.
- Older people, young children, pregnant or breastfeeding women, and people with heart disease, high blood pressure or lung disease are most at risk.
- During hot weather, drink plenty of fluids, stay indoors or in the shade, and avoid vigorous exercise.
- Seek urgent medical assistance if you or a family member show any signs of heat stroke.
You might also be interested in:
- Child safety - hot weather.
- Child safety in the car.
- Heat stress and heat-related illness.
- Heat stress and sport - reducing the risks.
- Water - a vital nutrient.
Want to know more?
Go to More information for support groups, related links and references.
This page has been produced in consultation with and approved by:
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Department of Health
Last reviewed: March 2012
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