​It is important to know the risks of heat, who is at risk, how to prepare, and how to protect ourselves and others.​

Last updated: 23 November 2023

​​What is extreme heat and is it dangerous for my health?

Extreme heat or heatwaves are periods of unusually hot weather. Climate change is resulting in more hot days and more intense heatwaves in Australia.

Extreme heat can cause severe illness, hospital admission and even death. Before, during and after a period of hot weather, it’s important that you keep cool and stay hydrated.

What is heat-related illness?

Your body normally keeps itself cool by sweating and moving more blood towards the skin.

In extreme heat, or if you are physically active in hot weather, your body’s natural cooling system can begin to fail. Your body temperature can increase to dangerous levels, leading to severe heat-related illness including heat stroke and heat exhaustion. More mild heat-related illness include heat cramps and heat rash. The strain of the body trying to keep cool can also worsen the symptoms of some existing medical conditions. For instance, someone with heart disease may feel dizzy or even have a heart attack.

Heat-related illness can affect anyone and is more likely to happen when you are dehydrated and can’t produce enough sweat to help you cool down. Know the signs of heat-related illness, how to give first aid, and how to get help.

Who is most at risk?

Hot weather can affect everyone, but some people are more vulnerable:

  • people aged 65 years and older
  • babies and young children*
  • pregnant women
  • people who are homeless
  • people with some medical conditions including heart disease, lung disease, diabetes, kidney disease, neurological disease, and mental illness
  • socially isolated people
  • outdoor workers.

*For specific advice on keeping babies and young children safe in hot weather, download the Babies and young children fact sheet.

Know the signs of heat exhaustion and heat stroke

Heat exhaustion

  • Headache
  • Dizziness, fainting, weakness
  • Irritability
  • Thirst
  • Pale skin
  • Sweating a lot
  • Nausea, vomiting
  • Decreased urine output (not weeing as much as usual)
  • Muscle cramps

First aid

Heat exhaustion needs to be treated as it can quickly become serious.

  • Cool down (see below)
  • Drink water.

If symptoms do not improve seek medical care. Call your doctor or healthdirect on 1800 022 222.

If symptoms are worsening and you are concerned about heat stroke, immediately call triple zero (000).

Heat stroke

  • Confusion
  • Slurred speech
  • Agitation and altered mental state
  • Loss of consciousness
  • Very high body temperature
  • Rapid breathing
  • A quick and strong pulse
  • Hot, dry skin or sweating a lot
  • Muscle twitching or seizures

First aid

Heat stroke is extremely serious. Immediately call triple zero (000).

Seek advice from a doctor before taking aspirin, ibuprofen or paracetamol to treat the symptoms of heat stroke as they may be harmful.

  • Cool down (see below)
  • Lay down and elevate the feet
  • Drink small sips of water if you can.

How to cool down

  • Get out of the heat to a cooler area indoors or shaded area outdoors.
  • Loosen or remove clothing.
  • Start to cool down any way you can: use a cool-water spray, apply a cool, damp sponge or cloth, wet clothes and skin, have a cool shower or bath, apply ice packs or crushed ice in a damp towel on the neck, groin and armpits.

Know the signs of heat cramps and heat rash

Heat cramps 

Signs include painful muscle cramps and spasms caused by your body’s loss of salt due to excessive sweating.

First aid

  • Drink water
  • Rest.

Heat rash

Signs includes a red, itchy rash with small bumps or blisters caused by excessive sweat blocking sweat glands

The neck, groin, armpits, inside of the elbow and under breasts are areas where heat rash can occur.

First aid

Heat rash normally goes away without treatment and can be helped by keeping skin cool and dry.

Visit healthdirect for more information about how to treat heat rash, and when to seek medical advice.

What if I have an existing medical condition?

Heat can worsen some medical conditions including heart disease, lung disease, diabetes, kidney disease, neurological disease and mental illness.

It is important that you talk to your doctor about how hot weather might affect your

health or medications. If your doctor

has asked that you limit your fluid intake, ask how much water you should drink during hot weather.

For more information, visit Heat risk: existing medical conditions.

Tips to prepare yourself and your home before hot weather arrives

  • Check that air-conditioners, fans, refrigerators, and freezers are working properly.
  • Learn about safe food and medicine storage during hot weather, and especially during and after a power outage.
  • Make a plan with family, friends and neighbours to keep in contact during hot weather and know who to call if you need help.
  • Make sure you have contact details for your doctor, pharmacist, or other source of good health advice such as Healthdirect.
  • Speak to your doctor if you are unsure about how your health condition or medication might affect your ability to cope during hot weather.
  • Make sure you have enough food and medicine for everyone in your home so you don’t have to go out in the heat.
  • Know where in your local area you can go to get out of the heat. Places that may be cooler than your home include:
    • air-conditioned public buildings such as libraries and shopping centres
    • parks with plenty of trees and shade
  • If you can, consider some changes to your home to help keep it cooler. Changes could include installing blinds, curtains, external awnings, shutters or other shading to prevent sun shining on windows and insulating your home. More information is available at Your Home.

Tips to keep yourself cool and hydrated in hot weather

Before, during and after a period of hot weather it’s important that you keep cool and stay hydrated by drinking water.

Keep yourself cool

  • Avoid being outdoors in the hottest part of the day as much as possible.
  • Limit physical activity to when it is cooler.
  • Wear light, loose-fitting clothes.
  • Wet your skin with cool water.
  • Place cool packs or crushed ice in a damp towel loosely around your neck and shoulders.
  • Take cool showers or baths or sit with your feet in cold water.
  • When outdoors, apply sunscreen and wear sunglasses and a wide brim hat to protect your eyes, face, and scalp.

Keep your home cool

  • Use air-conditioning, if available. If not available, use electric fans.
  • Close curtains and blinds to block out the sun and spend time in the coolest area of your home.
  • Use stoves and ovens as little as possible as these can heat up your home.
  • When it gets cooler outside, open your windows and doors to allow warm air out and let cool air in.

Keep yourself hydrated

  • Drink plenty of water regularly even if you don’t feel thirsty
  • Speak to your doctor if they have asked you to limit your fluid intake.
  • Carry water with you when outdoors.

For more information, advice and tips visit Beat the heat.

Current as at: Thursday 23 November 2023
Contact page owner: Environmental Health