SummaryRead the full fact sheet
- Heat kills more Australians than any natural disaster.
- Heatstroke is fatal in up to 80% of cases.
- Heat-related illness can be prevented.
- In hot weather, keep cool, avoid vigorous physical activity and drink water.
- Never leave children, older people or pets unattended in a car.
- Call Triple Zero (000) if a person shows any signs of heat exhaustion or heatstroke.
- Heat-related illness includes heatstroke, heat exhaustion, heat cramps and heat rash.
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Extreme heat can affect anybody. Those most at risk include older people, young children and people with certain medical conditions.
Heat-related illness occurs when our body is unable to cool itself enough to maintain a healthy temperature. Normally, the body cools itself by sweating, but sometimes sweating isn’t enough and the body temperature keeps rising.
Heat-related illness can range from mild conditions such as a heat rash or cramps to very serious conditions such as heatstroke, which can kill.
Overexertion in hot weather, sun or bushfire exposure, and exercising or working in hot, poorly ventilated or confined areas can increase your risk of heat-related illness.
Heat can also make existing medical conditions worse, for example heart disease.
People most at risk of heat-related illness
Anyone can suffer from heat-related illness, but those most at risk are:
- people over 65 years of age, particularly those living alone or without air conditioning
- babies and young children
- pregnant women
- people who are breastfeeding
- people with particular health conditions, such as heart disease, kidney disease, diabetes
- people taking certain medications that as a side effect impairs their body’s ability to lose heat.
Elderly people are more susceptible to heat-related illness than younger people because their body may not adjust well to sudden or prolonged temperature change. They are also more likely to have a chronic medical condition and be taking medication that may interfere with the body’s ability to regulate temperature.
Factors that contribute to heat-related illness
There are many factors which can cause heat-related illness, including:
- Dehydration – to keep healthy, our body temperature needs to stay around 37 °C. The body cools itself by sweating, which normally accounts for 70 to 80% of the body’s heat loss. If a person becomes dehydrated, they don’t sweat as much and their body temperature keeps rising. Dehydration may happen after strenuous exercise (especially in hot weather), severe diarrhoea or vomiting, drinking too much alcohol, taking certain medications (for example, diuretics) and not drinking enough water.
- Lack of airflow – working in hot, poorly ventilated or confined areas.
- Sun exposure – especially on hot days, between 11 am and 3 pm.
- Hot and crowded conditions – people attending large events (such as, concerts, dance parties or sporting events) in hot or crowded conditions may also experience heat-related illness.
- Bushfires – exposure to radiant heat from bushfires can cause rapid dehydration and heat-related illness. Bushfires usually occur when the temperature is high, which adds to the risk.
- Some drugs, such as ecstasy and speed, can also raise the body’s temperature.
Symptoms of heat-related illness
It is important to know the signs and symptoms of heat-related illness exposure and how you should respond. Symptoms vary according to the type of heat-related illness.
Some heat-related illnesses and their common symptoms include:
Deterioration in existing medical conditions
Deterioration in existing medical conditions is the most common health problem associated with extreme heat.
Heat rash, also known as prickly heat, is an itchy skin irritation caused by excessive sweating.
It can occur at any age, but is most common in babies and young children.
Heat rash occurs when the body sweats more than usual. It is caused by a blockage and inflammation of sweat ducts in heat and high humidity.
It is more common during summer and in hot climates.
Heat rash is most likely to occur on the neck, upper chest, waistline, in the groin, under the breasts, and in skin folds and armpits.
The symptoms of heat rash include:
- a cluster of small red spots or clear blisters
- an itch and prickling sensation
- redness and mild swelling of the affected area.
Symptoms of heat rash can last for several days.
Heat cramp symptoms include muscle pains or spasms, usually in the abdomen, arms or legs.
The cramps may occur after strenuous activity in a hot environment, when the body gets depleted of salt and water.
They may also be a symptom of heat exhaustion.
Heat exhaustion is a serious condition that can progress to heatstroke. It occurs when excessive sweating in a hot environment reduces the blood volume.
Warning signs may include paleness and sweating, rapid heart rate, muscle cramps (usually in the abdomen, arms or legs), nausea and vomiting, dizziness or fainting.
Heatstroke is a medical emergency and requires immediate medical attention.
Heatstroke occurs when the core body temperature rises above 40.5 °C and the body’s internal systems start to shut down. Many organs in the body suffer damage and the body temperature must be reduced quickly.
Most people will have profound central nervous system changes such as delirium, coma and seizures. The person may stagger, appear confused, have a fit or collapse and become unconscious.
As well as effects on the nervous system, there can be liver, kidney, muscle and heart damage.
The symptoms of heatstroke may be similar to heat exhaustion, but the skin may be dry with no sweating and the person’s mental condition worsens.
Treatment for heat-related illness
Treatment options vary according to the type of heat-related illness.
Apply first aid and seek medical assistance immediately if you, or someone you are with, shows any sign of heat exhaustion or heatstroke.
Heat rash treatment
Treatment for heat rash includes:
- Move to a cooler and well ventilated, less humid environment to cool down and stop sweating.
- Keep the affected area dry.
- Try using unperfumed talcum powder to increase comfort.
- Wear loose cotton clothing to help prevent overheating and avoid scratchy fabrics which irritate the skin.
- Do not dress or wrap babies and children in too many layers.
- Avoid plastic covered mattresses.
- Avoid using ointments or creams, as they keep the skin warm and moist, and may make the condition worse.
- A pharmacy can recommend treatments to ease itching and inflammation.
- Seek medical attention if the rash is not improving, if the rash appears infected, if the person affected is unwell or if you are concerned.
Heat cramps treatment
Treatment for heat cramps includes:
- Stop activity and sit in a cool place.
- Increase fluid intake.
- Rest a few hours before returning to activity.
- Seek medical help if there is no improvement, the person affected is unwell or if you are concerned.
Heat exhaustion treatment
Treatment for heat exhaustion includes:
- Get the person to a cool area and lay them down.
- Remove outer clothing.
- Wet skin with cool water or wet cloths.
- Increase fluid intake if they are fully conscious.
- Seek medical advice or call Triple Zero (000) for an ambulance if they are not improving or if you think they could have heatstroke.
Heatstroke is a medical emergency and requires urgent attention:
- 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 clothing and wet their skin with cool water, fanning continuously. Monitor their body temperature where possible and continue cooling efforts until the body temperature drops below 38 °C. Recommence cooling efforts if their temperature begins to increase again.
- Give the person cool water to drink if fully conscious and able to swallow. Otherwise, do not give the person fluids to drink.
- Position an unconscious person on their side and ensure they are breathing normally. If needed, perform CPR. 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 Triple Zero, ambulance or hospital emergency staff, while waiting for the ambulance.
Prevention of heat-related illness
Prevention is the best way to manage heat-related illness. Some tips to prevent becoming unwell include:
- Drink enough water – you need to drink more during hot weather, regardless of how active you are, even if you don't feel thirsty (check with your doctor if you are on limited fluids or fluid pills). Avoid alcohol, caffeine (such as coffee, tea) or drinks that contain lots of sugar. Don’t have extremely cold liquids, as they may cause stomach cramps.
- Avoid exposure to heat – stay out of the sun as much as you can.
- Protect yourself outside – if you must be outdoors, remember to protect yourself from the sun – ‘slip, slop, slap, seek and slide’ by covering exposed skin with lightweight clothes, using sunscreen and wearing a hat, ‘seek’ shade and ‘slide’ on sunglasses.
- Plan ahead – too much activity on a hot day can lead to heat stress. If you can, restrict activity to cooler parts of the day. Avoid physical activities like sport, renovating and gardening.
- Don’t leave kids, older people or pets in cars – even on cool days, cars can heat up to dangerous temperatures very quickly. People or pets that are left unattended in parked cars for even a few minutes are at risk of serious heat-related illnesses and possibly death. Never leave kids, older people or pets in a parked car, even if the windows are left open a fraction.
- Take it easy – rest often and, whenever possible, stay indoors or in the shade.
- Stay cool – and keep air circulating around you. Draw your blinds or curtains and use a fan or air conditioning if possible (if you don’t have air conditioning, consider visiting an air-conditioned shopping centre or public library. Keep yourself cool by using wet towels, putting your feet in cool water and taking cool (not cold) showers.
- Keep up your energy levels – eat smaller meals more often and cold meals such as salads.
- Check in on others – keep in touch with older, sick or frail family, friends and neighbours who may need help coping with the heat, especially those who live alone. Call them at least once on a hot day.
Where to get help
- In an emergency, call triple zero (000)
- Your GP (doctor) – if you, or someone you know, may be suffering from a heat-related illness
- NURSE-ON-CALL Tel. 1300 60 60 24 – for expert health information and advice (24 hours, 7 days)
- Department of Health – survive the heat information in community languages.
- Maternal and Child Health Line, Victoria Tel. 132 229 (24 hours, 7 days)
- St John Ambulance Australia – for information and resources on first aid
- Extreme heat and heatwaves, Department of Health, Victorian Government.
- Extreme heat, 2021, US Centers for Disease Control and Prevention.
- Hot weather, Sports Medicine Australia.
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