The first national ice swimming championship will be held at an outdoor pool in Alexandra this weekend.
Photo: 123RF
Athletes will compete in races of different lengths, with one key criteria: the water must be colder than five degrees.
The winners will be crowned New Zealand's Ice King and Ice Queen.
'It's not just as easy as swimming in a warm pool' - Ice swimming championship organiser
Event organiser Susan Sherwen told Morning Report the competition is not for the faint hearted with the water in the pool currently sitting at a crisp 3.5 degrees.
Competitors will have the option of competing in 100m, 500m or 1 kilometre races along with relay events.
"It's not just as easy as swimming in a warm pool, you're not allowed to do tumble turns basically for disorientation reasons but also so that we can keep an eye on you.
"It has its dangers but you come out with a real buzz, you get in the water and you get a really cold headache sometimes you get pain in other parts of your body as well or your heart rate goes up a bit," Sherwen said.
The competition attracted all kinds of people, not just those who choose to wear shorts and jandals in winter, Sherwen said.
However, she said swimming in such cold conditions could pose some risk to competitors' health with a particular risk of heart attacks.
All competitors will have to undergo full medical tests to alleviate this risk, this includes an ECG that will be checked by event medics.
"If there's anything dodgy we will keep an extra close eye but as it is we will have people on the side of the pool that will be watching each individual swimmer and just getting stats on them basically on their stroke rate and their time per length and all of that stuff."
Sherwen said many swimmers felt a certain buzz after completing their race, despite the freezing water leaving many competitor's stiff and shaky.
"Once you've stood up and your legs have regained their ability to stand up properly, because they go a bit like jelly, it's just like a bit of a high.
"I suppose that a lot of your top athletes or people who go running they get those endorphins and you just come out buzzing like 'yeah I did that'," she said.
Although many would be tempted to hop in the sauna or a hot shower after their race, she said it was important that swimmers took their time warming up as quickly heating the body's exterior can create a serious risk of collapse after a cold plunge.