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What’s the hottest temperature the human body can cope with?

5 December 2025
Person pouring water over their head.

Anyone who’s survived an Australian summer knows that stepping outside the comfort of the air-conditioned house can feel like stepping into a sauna. But have you ever wondered ‘how hot is too hot to survive?’

The highest core body temperature the human body can survive is around 43 degrees. Once your core body temperature rises above that point, your organs can start to shut down - a life-threatening situation that needs urgent medical care.

Extreme heat is becoming more common - especially during Australian summers. So it’s important to understand how heat affects your body, the signs of heatstroke or exhaustion, and how to stay safe when temperatures soar.

If you thought that Australia was one of the hottest countries, you wouldn’t be entirely wrong. In January 1960, Oodnadatta in South Australia reached the hottest temperature in Australia on record at 50.7 degrees. And in January 2018, the Western Sydney suburb of Penrith peaked at a steamy 47.3 degrees – making it the hottest place in the world at that time. However, Death Valley in California holds the record of the highest temperature ever measured on earth, hitting a top of 56.7 degrees in 1913.

So, how hot is too hot?

The Conversation put together an infographic that shows what heat and humidity your body could survive in.

An infographic displaying how long the human body can cope with temperatures between 30 and 60 degrees.
Chart translates air temperature and relative humidity combinations into critical environmental limits (CEL), above which core body temperature rises. The border between yellow and red areas represents the average CEL for young people at minimal activity.

What happens to the body at high temperatures?

When your body gets so hot that it can’t cool itself down, it’s called hyperthermia (this is different from hypothermia which happens when your body’s temperature drops to dangerously low levels).

One of the first stages of hyperthermia is heat exhaustion and stress - which can lead to heatstroke - so you might feel weak, dizzy, nauseous and thirsty. If you start feeling these symptoms, it’s important to drink plenty of water or other electrolyte-filled fluids, as these electrolytes will help regulate your heart rate, nerve function and muscles. When looking for a healthy electrolyte drink, opt for formulas that include potassium, sodium, magnesium, zinc, chloride, calcium, lysine, lithium and boron. Try and steer clear of drinks that contain artificial colours and flavours and sweeteners like glucose and corn syrup. Your best bet? Visit your local chemist for recommendations.  

How to stay safe as temperatures rise

Hot weather isn’t just uncomfortable - it can put real strain on your body. Here are some simple ways to stay cool and protect yourself:

  • Stay hydrated - Drink water regularly, even if you’re not thirsty. Avoid too much caffeine or alcohol, which can dehydrate you.

  • Keep cool - Use fans, air conditioning or cool showers. Stay indoors during the hottest part of the day (usually 11am–3pm).

  • Wear light clothing - Choose loose-fitting, light-coloured clothes made of natural fibres like cotton or linen.

  • Take it easy - Avoid heavy exercise or outdoor activity when it’s hottest. Rest in the shade or indoors.

  • Check on others - Young kids, older adults and people with medical conditions are more at risk in extreme heat.

When to reach out for help

Staying safe in extreme heat is about more than just comfort — it’s about protecting your health. If you start feeling unwell, don’t wait it out. You can book a telehealth consult through our partner, hub.health or via the nib App. It’s fast, secure and means you can get expert care without leaving the cool comfort of home.

Please note: The information throughout this article serves as broad information and should not replace any advice you have been given by your medical practitioner.