Swimmers who jump into open water often die in their first gasp as they are hit by “cold shock” – the involuntary breath caused by cold shock can make you inhale too much water in seconds.
You don’t even need to be underwater, a wave crashing over your face can cause a person to suck in as much as two to three litres of water – an adult can drown in just one-and-a-half. The reaction to going into cold water was coined as ‘cold shock’ by the UK’s leading expert on extreme environments, Professor Mike Tipton, in the 1980s as he investigated how the body reacts when the body is immersed.
The professor fears climate change has increased the risk of cold shock. He explained how the cold shock response peaks somewhere between 10C and 15C.
“So when you start getting air temperatures in the 30s in May when the water temperatures are in the low teens, you’ve got the Perfect storm,” he explains.
“That’s how we managed to end up with 19 people dead because normally you wouldn’t see that combination of air and water temperatures in May. Normally we lose one person a day in May to drowning, we lost nearly three times that number recently in unprecedented temperatures.”
Explaining what happens to the body, he said “it is the involuntary physiological response to sudden immersion in water typically below 15C, triggered by the rapid cooling of skin temperature. About 0.18mm below the surface of the skin you have cold receptors. And it’s those receptors that are responding.
“The gasp, the loss of control of breathing, that we now regard as the most dangerous of the responses associated with immersion in cold water accounts for the vast majority of the deaths we see in cold water. The gasp response dramatically decreases your breath hold time to a matter of seconds and significantly increase your chance of drowning”
“For people with pre-existing cardiovascular disease or hypertension or aneurysms, that sudden increase in the work of the heart as the body shuts down blood flow to the skin and pushes up the cardiac output can cause cardiac problems. These reactions are the body’s own fight or flight response to suddenly being in cold water and it lasts around 90 seconds, until the body adapts to your new surroundings.
“It’s the neurophysiological equivalent of ‘it’s okay once you are in.’ If you go sprinting down a beach into the sea, or into lake, or dive off a jetty, then there’s not much you can do about that. You’re in and you’re out of your depth. And you now have a powerful physiological response to deal with”.
What to do if you are hit by cold water shock
“What you should be doing in those ninety seconds is not thrashing around, not waving your arms, not try to swim. It’s to stay as still as you can, FLOAT TO LIVE.
“Do as little as possible. Roll onto your back. Tilt your head back until your ears are in the water to make your mouth really clear of the water and float until you get your breathing back under control. “ Make sure you go to a swimming pool and “practice your float”.
If you see others in trouble in the water don’t go in, instead PHONE the emergency services, tell the person to FLOAT and THROW them something to help them float.
“Around May and June is the most dangerous time of the year for cold water shock because the air temperature goes up very quickly but the water’s temperature stays low.
“The chances of drowning go up 70% when the air temperature goes above 30C, the high air temperature draws people to the water but the water temperature remains dangerously low.”
