"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."