Cold-water shock survival

A sudden immersion in cool waters can kill you. Ray Ford finds out why, first-hand

By Ray FordRay Ford


Photo by Randy Craig

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The lake’s November chill arches my back, pries my mouth open, forces my eyes wide until, overhead, I see the pewter sky through a cloud of bubbles. A second ago, I was up there, on the dock. Now I’m below the surface, flailing in liquid that feels as thick as gelatin, surprised by the water filling my mouth. A small voice, distant and oddly detached, muses: Am I going to drown?

The answer comes a second later, when my PFD delivers me, spluttering and gasping, back to the surface. Thank God, I think, still troubled by the underwater voice. Now I’ve got to last another 10 minutes, in a lake that’s nearly ice-water cold...

What is cold water shock?

A sledgehammer blow that can cause drowning, trigger heart failure, or chill victims so rapidly they’re unable to swim, hang on to a rope, or pull themselves to safety.

Cold water has been claiming lives as long as we’ve ventured near it, but it’s only during the past few decades that scientists have solved an ancient mystery: Why does cold water kill so quickly? How do strong swimmers succumb in seconds or minutes—long before hypothermia can set in?

The answer is the “huge, huge shock to the system” that comes with sudden, unexpected immersion in cold water, says Stephen Cheung, holder of the Canada Research Chair for Environmental Ergonomics. Known around St. Catharines’ Brock University as Dr. Freeze, Cheung is his own lab rat, dunking himself in chilled water while wearing nothing more than swim trunks. “People worry about falling in cold water and dying from hypothermia, but with cold shock, you’re not in the water long enough for that,” he says. “You die from drowning.”

So that’s why I’m a sodden and chilled guinea pig in Lake Muskoka. To help Cottage Life’s readers understand the threat that lurks off their docks and beneath their boats, my editor (in his warm, dry office) says, “We want show, not tell.”

The facts:

  • An average of 200 people in Canada die from cold-water immersion every year. Many of them while boating from April to May and September to November, according to a decade-long survey of drownings released by the Canadian Red Cross in 2006.
  • If you do go for a sudden, unexpected dunking, don’t count on your swimming skills—or a nearby dock or boat—to save you. When the Lifesaving Society looked at all the drownings in Canada during 2005, at least 36 per cent of the victims (and possibly another 17 per cent more whose swimming abilities weren’t identified) were thought to be average or strong swimmers. More sobering, at least 56 per cent of the deaths took place within two metres of safety. In other words, if a boat, dock, or rescue line was just out of arm’s reach (or sometimes even within it), the victims couldn’t help themselves.

Cold Water Boot Camp

“When you’re playing around cold water, you need to be prepared,” says Ted Rankine, a former chair of the Canadian Safe Boating Council. “If you have an accidental immersion, you need to keep your airway open. And to give yourself a chance to survive that initial shock, you need to be wearing a lifejacket.”

To prove those points, Rankine organized Cold Water Boot Camp. Held in April 2008, the camp pitted nine volunteers—including veteran sailors, a Coast Guard rescue specialist, a Canadian Armed Forces search-and-rescue technician, and a police officer with Winnipeg’s River Patrol—against the rigours of Lake Simcoe. “They’re the kind of people the public looks at and says, ‘If these guys had problems, so could I.’

He goes on: “You hear people say, ‘I can swim, I don’t need a lifejacket.’ Well, at Boot Camp we said, ‘Uh-huh? Swim this.’  ”

Rather than the boot camp’s group effort, this is a solo immersion: it’s just me—watched by the wetsuited divers of the Ontario Provincial Police Underwater Search and Recovery Team, just in case something goes wrong—versus Lake Muskoka’s 4.5°C water.

Ray's immersion

The plunge mimics what would happen if a cottager, doing that last job before pulling in the dock, or stowing the boats, tumbles into deep water. To stack the deck in my favour, I’ve got a vest-style PFD, long underwear, my doctor’s permission, and a team of paramedics on the dock—not to mention more members of the OPP, the Safe Boating Council, and the Lifesaving Society. I’ve also got a plan: I aim to fall gently backwards, with the sort of slow-motion Nestea plunge that will keep my face out of the water.

Everyone else on the dock seems far too cheerful, like the boisterous crowds that used to gather at public hangings. It’s time to get this over with.

Look away from the water, draw a breath, and...fall.

The blow drives the air from my lungs, contracting muscles and splaying fingers. Cold sweeps across my face, spilling between my lips. I’m suspended in twilight and the dock is invisible. So much for the gentle plunge, the dry face.

It’s hard to move, because the clinging water makes my limbs heavy and slow. My main concern is to get the water out of my mouth. I want to open up, and somehow spit it out without sucking any more in.

And then there’s the weird part. While all this is going on, the voice ruminates: Drowning, does it start like this? What happens next? (The rest of my brain—the part looking for a way out of the water—finds this deeply irritating.)

Then I rocket to the surface, the PFD tugging me back into the light. I’ve been under a long time, long enough to forget about the PFD, the divers, and the fact that this is really just an exercise.

What happens after falling in

Sudden immersion in cold water triggers an almost irresistible physical reaction, an extreme version of the shock you got as a kid when one of your friends dumped ice cubes down your back. Cold receptors in the nerves beneath your skin sense the shift from balmy to drastic chill, and send a storm of frantic signals: Something’s wrong. Prepare for action. Get air.

“Essentially, your body is stimulated to get ready for fight or flight,” says Dr. Freeze, Stephen Cheung. Your heart and muscles call for more oxygen, setting off an “inspiratory gasp,” a huge, lung-filling two- to three-litre gulp of air. If your face is already underwater as the signal is sent, that gasp is likely your last.

If you don’t drown immediately, there’s another complication: The body’s demand for air is so primal, so hard to override, that your ability to hold your breath in cold water is about half what it would be in a warm pool. If you can only hold your breath for, say, 15 seconds after you fall through the ice, it’s a lot tougher to keep the air in and the water out.

So it’s no surprise death can come quickly. Drowned kayakers have been found seated in their overturned craft, still gripping their paddles. Strong swimmers slip into the water and never resurface. During the 1990s, the Canadian Red Cross logged three cold-water deaths that each began as a trip to fetch water.

In my case, one moment I was falling toward the water, and the next I was beneath the surface with water in my mouth. My gasp happened so quickly, so reflexively, that I never felt it.

Back on the surface, spluttering and rolling water to one side of my mouth to keep from choking. The water has my ribs in a vise. I try to breathe, but can’t get air.

What sudden immersion does

It’s so easy to become panicked and disoriented. First, your heart is racing toward 150 beats per minute and, to keep it supplied with oxygen, you’re hyperventilating up to 100 litres a minute—10 times what you’d normally take in. Those with undiagnosed arrhythmia, or who don’t exercise, could suffer cardiac arrest. Others can’t expel the water they took in while submerged, or they draw in more water while hyperventilating.

“It only takes about a half cup of water in your lungs to get into a drowning state,” Cheung says. “It causes such a spasm in your lungs that you suck in more and more water.”

As if these reactions aren’t enough, “people think they’ll die from hypothermia if they don’t get out right away, so they thrash around while they’re hyperventilating,” Cheung says. “That’s really counterproductive to your survival. You can’t die from hypothermia that rapidly, even if you fall naked into ice water.”

That’s why a lifejacket or PFD helps to even the odds. By returning you to the surface and keeping you there, it buys time for you to grab your breath and cough out water. If you’re without a jacket, in rough water, frightened, and hyperventilating, those tasks are nearly impossible.

When my breathing slows, I realize my feet, ankles, elbows, and, um, testicles have all gone missing in action, as if they’ve dissolved in the cold lake. At the same time, my calves and thighs are on fire, with the blaze working its way toward the torso. Ted Rankine tells me I’ve been in for three minutes, and already I’m shuddering, a violent, full-body quake rippling from my gut. “Shook when he laughed, like a bowl full of jelly” keeps repeating in my brain.

Rankine interrupts to assign tasks to gauge my declining dexterity. The first job is to open a zip-lock plastic bag, pull out a two-way radio, and turn it on and off, twisting the dial between thumb and forefinger. Next, a nut and a bolt. I twist them apart, then thread them together. Rankine has me repeat this every few minutes as I lose the feeling in my fingers.

My hands become stiff and robotic, harder to control. It’s as if they’re drifting off in the distance, beyond the range of the signals coming from my brain. When the nut creeps onto the bolt for the third time, I’m spent. Nine minutes in the water...

Cold water sucks warmth from your tissues 25 times more effectively than cold air.

Swimming can boost the cooling by another 30 to 40 per cent, as movement displaces the warmer layer of water next to your skin with a constant flow of colder liquid.

Against this unrelenting cold, your body has only temporary defences. Shivering cranks your heat output from the equivalent of a 100-watt light bulb to as much as 500 watts. To concentrate the heat, peripheral blood vessels constrict to keep warm blood circulating where it’s most needed, in the torso and the head.

But shivering reduces fine motor control, making it hard to tie knots, turn knobs, or grip handles. As they cool, arms and legs weaken, and the fluid that lubricates your knuckles thickens like motor oil in February. No wonder shipwreck survivors have been unable to hang on to life rafts, pull on PFDs, unwrap plastic-covered emergency gear, or load and fire a flare pistol. So if you end up in cold water, Cheung warns, do everything you can to keep your hands working, even if it means holding them in the air while you tread water, “or you’re far more likely to die.”

Ten minutes in. Rankine orders me out. I feel comfortable in the water, and wonder if that’s a bad sign. When I try swimming, my stiff fingers claw the water instead of cupping it. My knees and ankles are rigid. I dog-paddle to the dock like an arthritic Labrador.

Up three rungs of an aluminum ladder, my unfeeling fingers curling and hooking each one. A painfully slow ascent, driven by the fear of falling back. Don’t want to slide beneath the surface again.

At last, on the dock, crawling on all fours. Dull and uncomprehending, I watch hands strip off my PFD, wrap me in a plastic sheet, and bundle me inside a sleeping bag.

Produced by Cold Water Boot Camp, featuring Ray Ford

Fall in the lake, pull yourself out. Simple, right? Not so fast: A sudden immersion in cool waters can kill you. In our Winter 2009 issue, Ray Ford writes about what happens when the body experiences cold-water shock. Watch as he finds out first-hand what it's like to be immersed for 10 minutes in a near-freezing lake.


This article was originally published on December 14, 2009

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