The posh name is hyperthermia and visitors to hot climates need to be aware of it, as I found out when I arrived in North Queensland from chilly Canberra. I was a keen diver and looked forward to diving on the Great Barrier Reef.
My previous experience was in the cold seas off the south coast of New South Wales. I had a thick wetsuit and didn't realise it was totally unsuitable for the tropics. I wore it on my first trip and soon discovered my mistake.
My dive buddy was slow to kit up and I hung around waiting for him. The sun shone down from a clear blue sky. I stretched out on deck and was suddenly overcome by a wave of nausea.
It was like being in a steam bath. The wetsuit was clearly at fault. I struggled to get out of it but was too weak and befuddled to manage the simplest of tasks. Fortunately, the skipper recognised my predicament and came to my rescue. The wetsuit was pulled off, water was thrown over me and I was fanned with a towel. My temperature dropped and I was soon well enough to go diving.
In the past, my fear had been of hypothermia, which refers to the body having too little heat. That usually comes on slowly and with plenty of warning. Hyperthermia is different. It can rush in and leave you so weak you lose control of what is happening.
Hypothermia takes time to overcome. The effects of hyperthermia usually go away swiftly once the body is given a chance to cool.
When you are in a hot climate you need to be aware of hyperthermia. Small children are particularly vulnerable. I came upon a panicking family in a Townsville park. Their toddler looked as if she was about to die. The infant was overdressed and badly dehydrated. The problem was soon corrected. The child was given a drink, undressed, doused with water and fanned. One wonders what might have happened if someone had not been there to give advice.
Stay cool and keep drinking. Pay particular attention to children. Small bodies loose liquids fast.
One of my bushwalking friends is a National Parks officer. One day when driving down a remote track she came upon a group of walkers. They were lost and in a state of confusion. All were suffering from hyperthermia. They'd drunk the last of their water and were near exhaustion. None was capable of rational thought. My friend bundled them into her vehicle and took them to hospital. But for this chance encounter they could have wandered off and died. One of the symptoms of heat exhaustion is an inability to think clearly.