“If you start to feel happy and warm, get out of the water immediately” is an obscure warning, but when you’re swimming the “Ice Mile”, you’d better heed the advice because it’s one of the first signs of hypothermia.

Ice Mile is just as horrific as it sounds – swimming a mile (1.609.3km) in frigid water < 5 degrees Celsius – but five Canberrans are doing it just for fun.

There’s no prize money or medal, just entry into an exclusive club of extreme swimmers who wear the coveted Ice Mile red jacket.

The funny thing is, qualifying for the event has been tricky for Kylie Sheffield and fellow swimmers Anna Cook, Amber Collins, Chris Loose and Paul Dailey – Canberra has not been cold enough.

Six words rarely uttered in our capital city.

The qualifier was supposed to be held recently at Smith’s Gap swimming hole (an old gravel quarry near Bungendore) but was postponed because the water was a balmy 11.4 degrees.

You see, it’s not an Ice Mile until it’s formally ratified by the International Ice Swimming Association. Until then it’s just a “nice mile”.

If you think swimming the Ice Mile is crazy … Kylie comes from Darwin.

“I found it a horrendous adjustment when I moved to Canberra 10 years ago,” said the 57-year-old. “It was only last year that I discovered this love for cold water swimming.”

A dread of cold water isn’t nearly as scary as a pathological fear of saltwater crocs.

“There’s really nothing in Lake Burley Griffin that’s going to hurt you apart from the algae, so I love it,” she said.

An ECG check is mandatory before attempting the Ice Mile (no sanity check surprisingly) because the risks can be deadly.

No wetsuits are allowed, just swimmers, goggles and swim cap.

“A lot of factors affect your tolerance for cold water – body weight is one, but gradual adjustment, repeated exposure and mindset are way more important,” Kylie said.

Training involves ice baths and cold plunges but this is Kylie’s first Ice Mile and nothing can prepare you for the real thing.

“One of the risks is ‘swim fail’, which is where your limbs can’t move, they’re frozen,” she said. “They’re not going to respond anymore to the signals that your body’s trying to send them and you can develop ‘claw hand’.”

Hypothermia’s another deadly risk but even if you survive the world’s hardest swim, it’s not over until after the “after drop”.

“You do get this feeling of euphoria afterwards but you also have to then deal with the ‘after drop’ about 10 minutes after you get out,” Kylie said. “You’ve got to slowly warm yourself up because blood’s leaving your inner core and trying to spread back out to your extremities. It’s a delayed effect.”

So the burning question is: why?

“Every time I jump into this kind of challenge, I ask myself the same question,” Kylie said. “It kind of started as a joke but what I really care about is doing it with my mates, that’s the big thing. These are the best bunch of people and every aspect of it is so much fun with them.”

The shrieks and squeals Kylie and her mates make as they dive into Lake Burley Griffin mid-winter can probably be heard for miles.

“When it first went down to 12 degrees last year, we very much sounded like how we remember we sounded when were in labour,” Kylie said. “I know, I know, we’re very conscious of the fact that it sounds crazy. I think we’re a bit nuts but in a good way, nuts in the best way.”

The Ice Mile will be held at Lake Crackenback on 8 August. For info: outdoorswimmingsociety.com/the-ice-mile