General information, not medical advice. NSW Health’s hot weather pages, linked at the foot of this page, are the official place to check. In an emergency, call triple zero (000).
Heat stroke is an emergency
NSW Health calls heat stroke the most severe heat-related illness and says it requires immediate medical emergency care. If you are concerned about heat stroke, call triple zero (000) immediately.
For the signs, symptoms and first aid, follow NSW Health’s page on heat-related illness.
Who is most at risk
NSW Health lists “older people, people with existing medical conditions, babies and young children, outdoor workers, socially isolated people, people who are homeless and pregnant women” as at risk of heat-related health problems.
Risk is not only about the body. NSW Health says your age, any existing medical conditions, where you live and work, and your social and economic status can all raise it. Babies and young children are limited in how well they can regulate their body temperature, and for people over 65, changes that come with age can add to the risk. For someone with an existing medical condition, heat can make the symptoms of that disease worse.
What heat does to the body
When you are exposed to heat, your body works to keep its temperature from climbing too high. It sweats more, so that heat leaves as the sweat evaporates, and it moves blood towards the skin to be cooled.
NSW Health gives examples of what works against that. Physical activity in high heat can overwhelm the body’s ways of regulating its temperature. Thick, heavy clothing gets in the way of sweat cooling the skin. Not drinking enough to replace what you sweat out can lead to dehydration.
The four heat-related illnesses
NSW Health groups heat-related illness into four conditions, and says dehydration can increase the risk of developing any of them.
| Condition | What NSW Health says |
|---|---|
| Heat stroke | The most severe. In extreme heat the body’s ability to cool itself can fail and its temperature can rise to a dangerous level; left untreated, this can cause permanent disability or death. |
| Heat exhaustion | The body’s response to losing water and salt in hot weather, usually through heavy sweating or too much physical activity. It must be treated, because it can quickly develop into severe illness. |
| Heat cramps | The mildest form: painful muscle cramps and spasms caused by the salt the body loses through heavy sweating. |
| Heat rash | An itchy red rash of small bumps or blisters in places where skin meets skin, which can develop when sweat blocks the sweat glands. It can appear on the neck, groin, armpits, inside of the elbow and under the breasts. |
NSW Health says it is important to learn the signs of all four, how to treat the symptoms, and when to seek medical help. Its heat-related illness page sets that out; follow the first aid there.
Where an air conditioner fits
NSW Health’s advice is to use air conditioning, if you have it, to keep a comfortable temperature indoors, and to use electric fans if you don’t. It adds a limit worth knowing: “At extremely high temperatures (around 39 degrees and above), fans can be less effective at keeping someone cool.” If your system both heats and cools, NSW Health suggests making sure it is set to cool when hot weather is forecast.
The rest of its everyday advice is about people rather than machines. Wear light, loose-fitting clothes. Stay out of the hottest part of the day as much as you can, and if you have to go out, find shade or shelter. Keep chores and exercise to early morning, when it is coolest.
Extreme heat can also cause power outages that affect an air conditioner or electric fan. The guide to hot afternoons and the NSW grid covers that side, and the guide to preparing a home for summer carries NSW Health’s whole plan.
Checking on other people
NSW Health asks everyone to check on family and friends who may be more at risk, before, during and after hot weather, and especially anyone who lives alone. Before the heat arrives, it suggests making sure they will be able to keep cool at home and have enough food and medication that they won’t need to go out in it. While it is hot, check in with them, and if you can’t visit, phone. It also suggests talking with them about ways to make their home easier in summer, such as blinds, air conditioning or fans.
Keep checking after the heat breaks. NSW Health says the strain of heat, and of broken sleep, can still affect people once the hot weather is over. For yourself, it suggests staying aware of your health in the days that follow and seeking medical help if you feel unwell.
Advice at any hour
For health information and advice, NSW Health points to healthdirect, which it says is available 24 hours a day, 7 days a week, or to your own doctor. The healthdirect line is printed in NSW Health’s plan, in the guide to preparing a home for summer.
NSW Health suggests checking, before summer, that air conditioners and fans are working properly. In NSW, servicing and maintaining an installed air conditioning system (not a portable plug-in unit) is licensed work, so a licensed technician is the person to look at one that isn’t.