Media release

From: Bond University

Amid all the claims by celebrities, sportspeople and influencers about deliberate cold-water immersion, there is one undeniable truth: it is not a pleasant experience.

First-timers gasp, swear, squeal and grit their teeth. Some even panic.

“It’s quite stressful,” says Kevin Kemp-Smith, an Assistant Professor at Bond University who still struggles with his own ice bath routine.

The chilling jolt got Dr Kemp-Smith and his colleague Dr Mathew Ono thinking.

What drives a healthy person to inflict such discomfort upon themselves? What do they get out of it?

To find out, the pair and their team conducted a scoping review that examined 13 international studies into cold water immersion (CWI).

They identified four themes.

* Physical and psychological benefits: Many of the studies found CWI can improve mood, reduce stress and have anti-depressant effects. It also helps people become more mindful and aware of their bodies, which can boost overall well-being.

* Sense of connectedness: CWI often involves social activities such as group swims which help people feel more connected to others. This can enhance feelings of support and happiness, which are important for mental health.

* Personal growth: The discomfort of cold water can help people build resilience and self-regulation skills, contributing to personal growth. This can improve the ability to handle stress and adversity.

* Connection with nature: CWI, particularly in natural environments such as lakes or seas, fosters a strong connection with nature which is associated with positive well-being.

The average temperature the participants in the studies were exposed to was 13.78C, with the coldest being 4C and the warmest 19.9C.

They were participating in CWI 2.5-8.5 days per month, with durations from 5-20 minutes.

Celebrities including Usher, Mark Wahlberg and Harry Styles have praised CWI.

Lady Gaga says it is part of her post-performance routine while big-wave surfer Laird Hamilton uses CWI to increase his resilience.

Dr Kemp-Smith says the physiological effects observed in the research echoed his personal experience.

“I do get that buzz afterwards. I really like that post–out of the pool feeling,” he says.

“You get a dopamine release and it flows on for hours and hours afterwards.

“It's definitely addictive.”

At its most basic, trying CWI at home is as simple as a few bags of ice from your local servo dumped in a bathtub.

Portable ice tubs are available for a little more than $100, while more expensive models with filtration and bacteria-killing ozone generators cost thousands of dollars.

The cheapest way to experience CWI is in nature.

That can be challenging on the Gold Coast where the ocean temperature only drops to about 21C in winter, which is more accurately described as barely-cool water immersion.

In contrast. waters off Sydney get down to 16.9C, while Melbourne reaches 11C.

Hobart is the natural environment for cold water swimmers year-round, with ocean temperatures ranging from 9-17C.

Anyone planning to try CWI for the first time should talk to their doctor first, with risk ranging from bacterial infection from dirty water to heart attack.

The shock of entering cold water can cause hyperventilation, increased heart rate and blood pressure and loss of breathing control.

It’s also important not to overdo it, as hypothermia can set in during extended exposure to cold water.

People with very low body fat are particularly susceptible to hypothermia.

Dr Kemp-Smith says CWI newbies should undertake no more than 2-3 sessions of 1-5 minutes per week, totalling no more than 10-15 minutes at temperate they can tolerate.