Cold-water shock survival
A sudden immersion in cool waters can kill you. Ray Ford finds out why, first-hand
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.
This article was originally published on December 14, 2009