What is a heat-related illness?

Heat-related illnesses happen when your body overheats and cannot cool down. They range from mild heat rash to life-threatening heatstroke.

Children, especially babies, are at a higher risk of developing heat-related illnesses. They do not sweat as much as adults and cannot regulate their body temperature as well. It is important to prevent your baby from overheating.

Other people at a higher risk of heat-related illnesses include:

• older adults
• people living with some medical conditions — heart disease, diabetes or obesity
• people taking certain medicines — diuretics
• people living with mental illness
• people working or exercising in the heat

What is heat stress?

Your baby can develop heat stress if their temperature rises above 37.5°C faster than they can cool down. This can happen from brief exposure to intense heat or longer exposure to mild heat.

What is heat exhaustion?

Heat exhaustion is a mild-to-moderate heat-related illness. It happens when your baby’s body temperature is between 38.3°C and 40°C. This is more severe than heat stress.

What is heatstroke?

Heatstroke is a severe heat-related illness. It is a rare and life-threatening medical emergency. Your baby’s temperature rises so high that their central nervous system (CNS) and other organs are affected. Your baby needs urgent medical attention for heatstroke.

What is severe dehydration?

Severe dehydration happens when your baby loses too much fluid (at least 11% of their weight). This is a medical emergency. It can cause serious complications.

What are the symptoms of a heat-related illness?

Heat-related illnesses cause a range of symptoms. It is important to recognise these symptoms and know what to do.

Heatstroke

If your baby has heatstroke, they will have symptoms showing that their brain and nervous system are not working properly, such as:

• seizures
• delirium
• coma

Your baby may also have:

• hot and dry skin because they cannot sweat anymore
• low blood pressure
• temperature over 40°C
• fast heart rate and breathing

Severe dehydration

If your baby is severely dehydrated, they may be less alert or hard to wake up. They also may have:

• pale or blotchy skin
• cold limbs
• sunken eyes
• low blood pressure, fast heart rate or breathing quickly
• sunken fontanelle on their head

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

What causes a heat-related illness?

Your baby can develop a heat-related illness if they:

• spend a lot of time outdoors
• don’t drink enough, and can’t cool down properly
• are overdressed
• are left in a parked car, even for a short time — the temperature inside your car can rise very quickly to extreme temperatures
• have a dry cloth draped over their stroller or capsule (for example, to create shade)
• have a fever or a medical condition that makes it hard for them to control their temperature

Read about babies in hot weather.

How is a heat-related illness diagnosed?

Your baby’s doctor can diagnose a heat-related illness by:

• assessing their symptoms and examining them
• measuring their vital signs, including their body temperature
• requesting blood tests
• asking you about your baby’s medical history and exposure to hot weather

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

When should I see my doctor?

Take your baby to their doctor if you suspect they have heat exhaustion or are unwell. Don’t wait — trust your instinct.

When to seek urgent care

While waiting for the ambulance:

• cool your baby in a lukewarm bath; if you do not have a bath, sponge your baby
• repeatedly moisten your baby’s skin with a moist cloth or spray
• continuously fan your baby
• give your baby liquids (only if they are awake and can swallow)

How is a heat-related illness treated?

Your baby’s treatment depends on how severe their heat-related illness is.

Self-care at home

If your baby has heat exhaustion, treatment at home includes:

• removing them from the heat to a cool spot
• removing extra layers of clothing
• spraying them with lukewarm water
• giving them fluids if they are dehydrated
• watching them until their symptoms go away

If symptoms do not improve, seek urgent care.

Treatment of heatstroke

If your baby has heatstroke, they need treatment in hospital. Treatment includes:

• cooling your baby down as quickly as possible — they may be immersed in cool water; fans will be positioned to blow cool air across their body
• if severely dehydrated, they will get intravenous (IV) fluids
• continuous monitoring to track their progress
• treatment of any complications

What are the complications of a heat-related illness?

Heat-related illnesses can cause complications, including:

• seizures
• loss of consciousness
• dehydration
• death

Heat stress and hyperthermia are also linked to sudden infant death syndrome (SIDS).

Can a heat-related illness be prevented?

Here are some tips to prevent heat-related illnesses:

Here are some tips to prevent your baby from overheating when sleeping:

• Put your baby to sleep on their back, with their head uncovered.
• Your baby should sleep on light, cotton sheets.
• Your baby should sleep in a ventilated and comfortable room. Keep heaters away.
• Make sure air can circulate around their cot.

Read about keeping babies cool in hot weather.

Read about dressing a newborn.

Read about sun and heat protection for babies and kids.

Resources and support

• Visit The Sydney Children’s Health Network to learn about heat exhaustion and heatstroke.
• The Royal Women’s Hospital has information about heatwave precautions for babies and young children.

Looking for information for Aboriginal and/or Torres Strait Islander people?

NSW Health has a ‘Beat the Heat’ resource for Aboriginal and/or Torres Strait Islander people.

Do you prefer to read in languages other than English?

NSW Health has translated its resource about keeping babies safe in the heat into many community languages.