Drowning deaths could be reduced if people were taught how to respond to the initial shock from cold water, new research shows.
As part of a University of Otago study, participants dropped into 10C water learned to halve their 'gasp response' with repetition and basic mental training.
The results had the potential to dramatically reduce New Zealand's high drowning rates, said associate professor Chris Button of the school of physical education, sport and exercise sciences.
Mr Button and his colleagues teamed up with Water Safety New Zealand to test the body's response to sudden cold water immersion.
They found people who were plunged into cold water initially recovered from the shock in two to three minutes, but with training that response was halved.
"After a week or so of repeated immersions, coupled with mental skills training, and basic suggestions to improve their treading water technique, the participants were much calmer in the cold water," Mr Button said.
"The change in behaviour blew me away. I have never seen a response as dramatic as this in research before."
Drowning is the third highest cause of unintentional death in New Zealand, with 81 deaths recorded last year.
It is thought the body's shock response to cold water is partly to blame, particularly for drownings which occur in the first few minutes of falling into the water, because of the 'gasp response' which can cause people to take a sharp intake of breath and inhale water into their lungs.
The research team put together a set of practical tips people can learn to counter that response, and have recommended they be taught in swimming lessons.
Nick Mulcahy, lifesaving service and education manager at Surf Life Saving New Zealand, described it as "great research" which would help contribute to wider water safety education.
"I think it's one thing that we'll definitely look at, moving forward. When we look at improvements to our education programme these are the kinds of things we look at, what studies have been done, what new information is out there.
"It's one of the things that adds to the picture and ... over time, as a sector, we can really bring these things together and inform people as much as we can with what we know."
Lindsay Sturt, deputy director of Maritime New Zealand, said it welcomed any work to reduce drowning deaths.
"Our number one recommendation for boaties is that they wear lifejackets at all times. This can reduce the stress for people if they end up in the water because they know they will float, reducing the likelihood of panic," he said.
- Learn how to tread water effectively and associated survival skills; not just how to swim
If you're in the water:
- Hold your breath if possible for the first 5-7 seconds upon immersion
- Float first, using breathing regulation strategies and mental skills to combat hyperventilation and panic
- Plan the best course of action for the situation (such as stay and wait for help, find flotation aid, swim to safety)
(Source: University of Otago/Water Safety NZ)