Australian summers can be absolutely brutal, and they're getting worse. Heat kills more Australians than any other natural disaster, which is something that catches a lot of people by surprise. Between 2000 and 2018, we averaged 26 heat-related deaths every year, with three-quarters of those happening during heatwaves. That's not counting the people who end up in hospital or the near-misses that happen every summer. The thing is, our summers aren't just hot anymore. Climate change is bringing us more extreme temperatures and longer heatwaves. The Bureau of Meteorology's 2024 State of Climate report isn't pulling any punches either. We're looking at more hot days, a longer fire season, and heavier rainfall when it does come. Just last December, parts of Australia saw temperatures 12 to 16 degrees higher than they should be for that time of year. Some places hit 45 degrees or more. Here's a bit of perspective on just how hot it can get. The highest temperature ever recorded in Australia is 50.7 degrees Celsius, and it's happened twice. Once in Oodnadatta, South Australia, back in 1960, and again in Onslow, Western Australia in 2022. When you're dealing with temperatures like that, you're not just uncomfortable, you're in genuine danger.

Your body is pretty clever at keeping itself cool. When it gets hot, you sweat and your blood flow redirects to your skin to help release heat. But there's a limit to how much your body can handle. When it's too hot for too long, or you're not drinking enough water, or you're pushing yourself too hard, your body's cooling system can fail. That's when things get serious.

The progression from feeling a bit off to being in real trouble can happen faster than you'd think. It starts with dehydration, which is simply when your body doesn't have enough fluid to do its job properly. We lose water every day through normal things like breathing, sweating, and going to the toilet.

Usually, we replace it by drinking and eating. But in extreme heat, especially if you're active, you can lose fluid faster than you're taking it in. Early warning signs are easy to miss if you're not paying attention.

Headaches, dizziness, feeling tired or weak, getting irritable, or finding it hard to think clearly. These are all your body's way of saying "Hey, something's not right here."

The problem is, a lot of people push through these symptoms, and that's when it can escalate. Heat cramps come next for people who are sweating heavily during activity. Your body loses salt and water, and your muscles start cramping up. It's painful and it's a clear sign you need to stop what you're doing, get somewhere cool, and start replacing those fluids and salts. Heat exhaustion is where things get properly serious.

This happens when you've lost too much water and salt through sweating. You might feel faint or dizzy, be sweating excessively, have cool, pale, clammy skin, feel nauseous, have a rapid but weak pulse, and experience muscle cramps. Your core body temperature rises to somewhere between 38 and 39 degrees.

At this point, you need to act fast. Get to somewhere cool, lie down with your legs elevated, remove excess clothing, and start cooling down with water. Have a cool shower if you can, or use wet cloths on your forehead, neck, wrists, and groin. Keep a fan on you and drink water steadily. The absolute worst-case scenario is heatstroke, and this is a genuine life-threatening emergency. Your core body temperature hits 40 degrees or higher.

You might have stopped sweating despite being dangerously hot, your skin could be hot and dry, your pulse is racing, and you're confused or even unconscious. If someone's showing these signs, call triple zero immediately. Heatstroke can kill, and it can happen quickly. Even if someone survives, it can cause permanent disability, trigger heart attacks or strokes, and make existing health problems much worse.

While extreme heat can affect anyone, some people are more vulnerable than others.

The elderly, especially those over 65, are at higher risk because their bodies don't regulate temperature as well. Babies and young children can't tell you how they're feeling, and their bodies are still developing.

Pregnant women are dealing with extra physical stress. People with chronic health problems like heart disease, diabetes, kidney or lung disease are more susceptible.

And people who are socially isolated might not have anyone checking on them. If you've had heat stroke before, you're more likely to get it again. People with dementia or other conditions that affect their ability to recognise and respond to heat are particularly vulnerable.

Certain medications can make you more susceptible too, including some drugs for high blood pressure and depression. Even being overweight or having an infection increases your risk.

There's no magic number for how long you can safely be in the heat because it depends on so many factors.

The temperature, humidity, what you're doing, your age, health status, and whether you're used to the heat all play a role. But here are some practical guidelines.

When you're active in the heat, you should be drinking water every 15 to 20 minutes, whether you feel thirsty or not. By the time you feel thirsty, you're already getting dehydrated. Take shade breaks every 30 to 45 minutes during strenuous activity.

In extreme heat above 40 degrees, dehydration can start within 30 to 60 minutes if you're active and not replacing fluids.

On extreme heat days when temperatures hit 40 degrees or more, outdoor exposure should be limited to essential activities only. Don't do strenuous outdoor work or exercise, and definitely stay indoors between 10am and 4pm. On very hot days between 35 and 40 degrees, keep outdoor activities to 30 to 45 minute blocks with proper breaks, skip strenuous exercise during peak heat, and keep up constant hydration. Even on just hot days between 30 and 35 degrees, you still need to take 10 to 15 minute shade breaks every hour and increase your fluid intake by 50 to 100 percent.

Before you even step outside on a hot day, start preparing.

Drink plenty of water 30 minutes before going out. Check the weather forecast and UV index. Plan any physical activities for the cooler parts of the day. Wear lightweight, light-coloured, loose-fitting clothes made from breathable fabric. Throw on a hat, sunglasses, and apply SPF 50+ sunscreen at least 20 minutes before going outside.

While you're out there, keep drinking every 15 to 20 minutes. Sports drinks can help replace electrolytes, but avoid caffeine and alcohol because they'll dehydrate you faster.

If you can, mist yourself with water from a spray bottle. Seek shade whenever possible and wet your clothing, hat, or a bandana with cool water to help keep cool. At home during hot weather, prepare your space to stay cool. Use fans or air conditioning if you have them.

Set your air con between 23 and 26 degrees. Every degree colder than that adds about 10 percent to your running costs.

Close blinds and curtains during the hottest part of the day. If you don't have air conditioning, spending time in shopping centres, libraries, or other air-conditioned public spaces during the worst of the heat can help.

For daily hydration, men should aim for about 10 cups or 2.5 litres per day, and women about eight cups or two litres.

But that's just baseline. In summer heat, especially if you're active, you might need to double that. A good way to check if you're drinking enough is to look at your urine. If it's clear or pale yellow, you're probably doing okay. If it's dark, you need to drink more.

Kids need extra attention in the heat. For infants and young children, use proper rehydration solutions like Pedialyte rather than trying to make your own at home.

Never, ever leave children or pets in a closed car, even for "just a minute." Cars heat up incredibly quickly, even when parked in shade with windows cracked.

A child can develop heatstroke in minutes in a hot car. Watch children closely for signs they're struggling with the heat. They might not tell you they feel unwell until it's serious.

Make sure they're drinking regularly and taking breaks from play in the shade.

Check on elderly neighbours, relatives, and friends during heatwaves.

 They might not realise how hot they're getting or might not be able to help themselves. Make sure they have working fans or air conditioning and are drinking enough.

 Help them identify a support network of family, friends, or neighbours who can assist them during extreme heat. If you have a medical condition, talk to your doctor about how heat might affect you and what extra precautions you should take.

Ask about medication storage too, because some medications can be damaged by heat. Heat can make conditions like kidney disease, lung disease, diabetes, and cardiovascular disease much worse.

Outdoor workers cop it worst during summer. They're exposed to up to ten times more UV radiation and heat than indoor workers. If you're working outdoors, your employer should provide regular shade breaks (at least every hour in extreme heat), plenty of cool drinking water, and modify work schedules to avoid the worst of the heat. Workers need to watch out for each other and speak up if they or a colleague are showing signs of heat illness.

You need to stop immediately if you notice certain warning signs. If you stop sweating despite being hot, that's a major red flag for heatstroke. If you're feeling faint, dizzy, excessively sweaty, clammy, nauseous, or your pulse is rapid but weak, stop what you're doing and get cool. Any confusion or difficulty thinking clearly is serious. If your body temperature hits 38 or 39 degrees, you're in the heat exhaustion zone. Call triple zero straight away if you or someone else feels faint, confused, can't drink, has a seizure, or has a temperature of 40 degrees. Don't wait. Don't try to tough it out. Heatstroke kills, and the sooner you get help, the better the outcome.

If you've been pushing it in the heat and are feeling the effects, take recovery seriously. Get to somewhere cool and lie down. Remove excess clothing and loosen anything tight.

Immerse your hands and feet in cold water if you can. Use cool, damp cloths on your forehead, neck, wrists, and ankles. Keep a fan on. Have a cool (but not freezing cold) shower. For rehydration, drink cool water, sports drinks with electrolytes, or oral rehydration solution. Take small, frequent sips rather than gulping down huge amounts at once. After heat cramps, rest for a few hours before going back to whatever you were doing. After heat exhaustion, give yourself at least 24 hours to recover and watch for any worsening symptoms. ### The Acclimatisation Factor If you're not used to the heat, don't expect to jump right into strenuous activity in hot conditions. Your body needs time to adapt. Gradually increase your time spent outdoors over a period of weeks. Athletes need several weeks to properly acclimatise before competing in hot weather. When you travel to somewhere hotter or at the start of summer, take it easy for the first week or two while your body adjusts.

Some rules are absolute when it comes to heat safety. Never ignore symptoms of heat illness because it progresses rapidly.

Never leave anyone in a car, even for a minute. Never exercise or do strenuous work in extreme heat; reschedule it for when it's cooler.

Never wait until you're thirsty to drink; stay ahead of it. Never assume you're already acclimatised to the heat; it takes weeks for your body to adapt properly.

The reality is there's no single "safe" duration for being in the heat. What you can handle depends on too many variables. The key is to monitor yourself and others constantly, take breaks every 15 to 20 minutes for water, rest in shade every 30 to 45 minutes if you're active, and stop immediately if you feel unwell. When in doubt, get out of the heat. Heat illness is progressive. What starts as just feeling a bit off can rapidly escalate to heat exhaustion and then to heatstroke. Each stage is more dangerous than the last. Stay hydrated, stay cool, check on vulnerable people around you, and don't hesitate to call triple zero if someone's showing signs of heatstroke. With climate change bringing more extreme heat events, being prepared isn't optional anymore. It's essential for surviving Australian summers. The old advice to just "harden up" or "she'll be right" doesn't cut it when temperatures are regularly hitting 40 degrees or more.

Take the heat seriously, plan ahead, and look after yourself and each other.