The winds swirling over the Graveyard of the Pacific are a raw 52°F. I’m not exactly dressed for the weather. Actually, I’m not dressed at all, unless you count the electronic thermometer residing in my colon.
Retired Coast Guard Rear Admiral Al Steinman, M.D., a hypothermia researcher, has just talked me through the rectal probe insertion process. Now he snakes an attached wire to a nearby computer console, flips some dials, and announces that my core body temperature is just over 100°F. In three minutes, I’ll be taking a late- autumn dip into the cold broth off Washington’s Cape Disappointment Coast Guard Station-unless, that is, I can win a last-minute medical reprieve. I suggest I may be feverish. “No, no,” Steinman assures me. “Rectal temperatures always run a degree or so higher than the oral 98.6. You’re completely normal.”
Well, maybe not completely normal. I am about to jump into bone-chilling water. But that’s not due to a mental defect, rather, it’s to give boaters a first-hand look at the effects of hypothermia.
If you don’t live in the tropics, getting chilled to the core is not a hypothetical situation. According to a Coast Guard study, some 8,000 recreational boating accidents are reported annually. In one year, these accidents caused 4,555 injuries and 821 deaths. Approximately two-thirds of the fatalities occurred following immersion in water. Hypothermia or drowning-and often a hellish mixture of the two-accounted for a whopping 74.3 percent of those deaths. With that in mind, I’m going to become a human popsicle so you can understand what hypothermia does and how to survive it.
Mr. Frosty
If anyone in the country knows how to supervise such a bone-chilling exercise, it’s Admiral Steinman. In a series of experiments in the mid-1980s, Steinman monitored the plummeting core body temperatures of volunteer “Popsicle Men,” who agreed to enter bitter waters under a host of different sea conditions, outfitted in everything from neoprene survival suits to T-shirts. In the process, Steinman has helped advance scientific understanding of what happens to people in cold-water immersion situations.
For BOATING readers, I don some Speedo trunks, then step to the end of the fueling dock, Steinman holding my wire tail like a wedding attendant. En route, we pass paramedic Doug Beardsley, ready to intervene. Beardsley shows me his bag of tricks: a forced-air rewarmer, warm IV fluids, intubation gear, an electric defibrillator, and various heart drugs. “Hopefully, we won’t have to go as far as using the cardiac stuff on you,” he says, “but I have it if we need it.”
The combination of mild activity and major anxiety causes my core temperature to rise to 100.3. A boatswain’s mate hands me a life jacket and ties a rope to it in case he has to yank me out of the water. Steinman gives me the nod, and I kneel down to enter the ocean. The water temperature hovers around 60°F. This may not seem that cold, but remember: Water is 25 times more efficient at sucking heat from the body than air. For posterity, here’s a step-by-step account of what happens when you’re stuck in the drink.
Chillin’ Out: 9:30-9:32 a.m. The instant I enter the water, the cold shock triggers an involuntary gasping for breath. Try as I might, I can’t seem to take in or hold a decent lung of air. This is called “truncal immersion reflex”-a phenomenon now believed to be the root cause of sudden drowning syndrome.
“If your head is underwater and you gasp and hyperventilate,” Steinman explains from his perch on the dock, “you’re not going to make it.” Thank goodness for life jackets.
Dr. Gordon Giesbrecht, a Canadian hypothermia researcher, once had volunteers hold their breath on land and then upon entering cold water. People on land averaged 70 seconds, but in 50-degree water, only 25 seconds.
Besides the effect on respiration, my skin stings. I hardly notice the surge of adrenaline that temporarily escalates my heart rate and blood pressure. My body has begun to mount a hypothermic defense-a response honed by evolution to retard heat loss. Paradoxically, the initial cold shock begins to wear off after only a minute. I start breathing normally, my skin stops stinging, and I feel almost comfortable-the cold has become an anesthetic.
Icy Hot: 9:32-9:44 a.m. That numbness, alas, proves short-lived. My hands and feet now prickle with painful pins and needles-evidence, says Steinman, that my peripheral blood vessels are constricting in an effort to shunt warm blood from my extremeties to my vital internal organs. “Pretty soon,” he explains, “your hands and feet will be nearly the same temperature as the surrounding water.”
By 9:36, his prediction comes true. A Coastie asks me to wriggle my now blanched fingers and thumbs in sequence, which proves surprisingly difficult. “This loss of manual dexterity is a real problem in survival situations,” says Steinman. “When the muscles and nerves get cold enough, it’s virtually impossible to activate a flare or work a radio.”
By the 10-minute mark, I’m confident my time in the drink is drawing to a close. “So what’s my temperature now?” I ask.
“It’s still 100.3,” says Steinman. “There’s typically a lag before it starts to fall.” This could take longer than I thought. At 14 minutes, my core finally drops to 100.2. But my subsequent celebration causes it to jack back up.
Cool Runnings: 9:44-10:02 a.m. When I ask Steinman what gives, he says that not all bodies chill at the same rate. A major determinant is your ratio of volume to surface area. “The more you’re like a bowling ball,” says Steinman, “the longer you’ll take to cool. When you think about it, fat is a perfect custom-fit wetsuit.” Fat-free stick figures, on the other hand, tend to chill quickly.
At 6’1″, 178 pounds, and around 20 percent body fat, I’m neither a bowling ball nor a stick figure-one reason my cooling rate is proving hard to predict. Steinman suggests that if I want to stay warm as long as possible, I should roll into a ball and remain still. Hypothermia researcher John Hayward coined this strategy the HELP (Heat Escape Lessening Position) configuration. It works by reducing exposure to the body’s highest heat-loss areas-the neck, groin, and armpits.
To hasten heat loss, Steinman recommends doing the opposite. To this end, I dunk my head and begin spirited treading. This runs contrary to the common belief that you should keep moving to keep warm. At 9:59, this full-body frenzy finally yields results-my core temperature drops to 100.2 then 100.1. Shortly after 10 a.m., it’s fluctuating between 100.1 and 100 flat, and my body inaugurates the next major tactic in its hypothermic defense.
“Your brain is sensing the temperature drop,” says Steinman, “initiating the shivering response.” Though useful on land, shivering does no good in cold water, because the heat it generates is immediately sucked away. My body doesn’t understand this and reacts by shivering harder. At 10:02, I finally hit 99.9°F, and I worry my teeth might break from their clacking.
Ice in the Veins: 10:02-11:09 a.m. A new unpleasant symptom arises: My bladder feels like it’s about to explode, but the combination of onlookers and body-wracking shivers makes it hard to pee. I manage, but within 14 minutes, I have to go again. It turns out cold diuresis is another reaction to hypothermia. As more and more blood is constricted away from the periphery to the core, blood pressure mounts. Specialized cells in the neck and kidneys sense this increase and instruct your body to relieve the pressure by eliminating fluid.
Between nonstop shivering and several more urinary episodes, my linear cooling rate stabilizes at slightly over 3°F per hour. Exactly 1 ½ hours after entering the water, my core temperature is 96.4. During his earlier experiments, Steinman yanked volunteers after 90 minutes, but I beg him to let me stay in until my core temp hits around 95°F. Steinman ogles me peculiarly, searching for evidence of another symptom: massively impaired judgment. But that usually happens around 91°. He agrees to let me go a little longer.
Nine minutes later, I reach my goal: 95.9°F. Steinman signals two attendants, who hoist my chilled frame onto the dock. I wobble on shaky legs, the victim of a plummet in blood pressure now that the ocean’s “blood pressure cuff” has been removed.
“You have bigger ones than I do, sir,” says one of the young Coasties. Replies another, “Not now he doesn’t.”
The Ice Man Cometh: 11:09-11:15 a.m. On shore, Beardsley has fashioned a rewarming bed. To reach this, I need to walk less than 10 yards. By the time I make it there, my body temperature dips another half degree. This phenomenon, explains Steinman, is called “after drop,” triggered when exercise causes the cold blood in my extremities to recirculate back to the core.
In victims of severe hypothermia, after drop can be fatal. The reason: A cold heart is a cranky heart. The blood recirculating from the extremities is more than just cold-it’s borderline poisonous, thanks to an accumulation of unfiltered metabolic wastes. To an already vulnerable heart, this is a prescription for cardiac arrest.
Which is why rescuers such as Beardsley handle severe hypothermia victims with extreme care: minimize jostling, keeping them horizontal, and rewarming from the core outward. Some state-of-the-art ways to do this include providing heated, humidified oxygen; transfusing with 102°F fluids; and placing victims on a heart-lung bypass machine that removes cold blood, rewarms it, and recirculates it.
Fortunately, I have what Steinman defines as “significant mild hypothermia,” which means my odds of cardiac arrest are nil. By the time I hit the rewarming bed, my rectal readout has dropped to 95.6°F. “Your heart,” says Steinman, “is probably another degree colder than that because the rectal temperature lags the core.” I am now literally the most cold-blooded person I know.
Mr. Heat Meiser: 11:15-11:20 a.m. Beardsley covers me with the Bair Hugger 505, a forced-air rewarmer that looks like a pool raft connected to a hair dryer. When he throws the switch, lukewarm air exits the vent holes and circulates over my goose-pimpled flesh. I tell myself that my skin is still too cold to sense warmth. Then I start a new round of shivering, far more severe than when I was in the water. In five minutes, my temperature climbs to 96.2 and the shivering stops. I feel colder than I have all day.
Hot to Trot: 11:20 a.m.-12:20 p.m. When my temperature suddenly drops back to 96.1, Steinman looks nervous-clearly, this is not the direction I’m supposed to be heading. For seven minutes, my temperature doesn’t budge. Beardsley checks the Bair Hugger and finds a problem with the electrical outlet. Steinman puts some chemical heat packs under my neck and feet and Beardsley covers me with a space blanket and two thermal blankets. After five minutes, my temperature creeps up 0.1 degree. After a full hour, I’m up to 96.8-still 3.5 degrees below this morning’s fever.
Heartwarming Moment: 12:20-1:09 p.m. Steinman suggests a warming technique pioneered 30 years ago by Lief Vangaard, a physician in the Danish Navy. The Coasties fill four buckets with warm water, one each for my hands and feet. Studies have shown hand and foot immersion can be a safe and effective way to rewarm victims. The water feels great, but my core temperature advances at a snail’s pace.
Beardsley walks me over to an ambulance, then ferries me to the Coast Guard station’s shower room. En route, my temperature drops again. Then the blessed hot water splashes over my body, and for the first time in three hours, I feel warm. After 25 minutes my core reaches 98.5 and I begin, ever so slightly, to sweat.
Some Like It Hot: At lunch, I down three pints of ice water. “Once you rehydrate all the fluid you lost from the diuresis,” Steinman says, “you should have no residual effects from today’s experience.”
It’s hard not to imagine hypothermia victims whose fates were not so fortuitous. For today’s experiment, I immersed myself inches off a Coast Guard dock, flanked by a dozen folks trained in search and rescue, a fully equipped paramedic, and one of the world’s most knowledgeable experts in immersion hypothermia. Despite all this, my rewarming still went slightly awry, something to keep in mind the next time you venture offshore.
Undoing a Dunk: If you’re planning to cruise chilly seas, it’s critical to be prepared for an inadvertent dunk. Depending on how cold the water is-and how far from populated areas you plan to venture-a survival suit may be de rigueur, says Al Steinman, M.D., a retired Coast Guard Rear Admiral and one of the nation’s preeminent immersion hypothermia researchers.
A man overboard situation is an all too likely occurrence. Assuming you manage to get the victim safely back on deck, you’ll need to assess his condition and take prompt action.
If the hypothermia is moderate to severe (rectal body temperature below 90°F, confusion, cessation of effective shivering), call the Coast Guard immediately so a Medivac unit can take the victim to a hospital for emergency rewarming. Until help arrives, handle the person gently to reduce the chance of cardiac instability. Provide insulation and an external heat source, but don’t give any food or beverages-they can cause choking.
For milder hypothermia (rectal body temperature above 90°F), if the victim is lucid and effectively shivering, he can usually rewarm effectively on his own, provided you stem any further heat loss. But there are still steps you can take.
- -Shelter the victim from wind and rain.
- -Remove any wet clothes and replace with dry.
- -Insulate his body with a space blanket. If you don’t have one, try a sleeping bag. In a serious pinch, wrap him in your boat’s canvas.
- -Apply external heat, such as chemical heat packs or hot-water bottles, to high heat exchange body areas such as the armpits, neck, and groin. Wrap him in a towel so you don’t burn the skin.
- -If you’re certain the victim can swallow normally, offer warm liquids and high-energy foods. Never give the victim alcohol.
- -Consider crawling into the sleeping bag or under the covering with the victim. Though studies have failed to show this hastens rewarming, some people find it psychologically appealing.
- -Once the victim’s temperature is back to normal, make sure he drinks plenty of liquids to make up for the dehydrating effects of hypothermia.
