As the snow storm wreaks havoc on the East Coast - with power lines down and commuters in chaos - I'm reminded of a surprising fellow named Gordon Giesbrecht, a physiologist and director of the Laboratory for Exercise and Environmental Medicine at the University of Manitoba in Winnipeg. Giesbrecht likes to dunk himself in tanks filled with ice to study the physical effects of the cold. His nickname is Professor Popsicle.
Giesbrecht has gone hypothermic at least 39 times, lowering his body temperature in one experiment to 88.16 degrees (the point when you actually stop shivering and a couple of degrees away from blacking out). After freezing himself again and again, Giesbrecht has become an evangelist about surviving in cold weather. What follows are a few of his tips (and some others) gleaned from my research for my new book The Survivors Club.
Myth #1: Cold kills quickly. "If you think you have just minutes to live, that becomes a self-fulfilling prophecy," Giesbrecht explains. "If you decide you're going to die, you tend to panic and then you do things that are more likely to bring about a negative result." Some 95 percent of those who perish in cold water aren't actually hypothermic, he says. In fact, their body temperatures turn out to be almost normal. The cold doesn't kill them. It's the terror, which leads to drowning and heart attacks.
So what should you do, for instance, if you end up in an icy pond? Giesbrecht recommends a straightforward 1-10-1 formula: You have one minute to get your breathing under control, 10 minutes of meaningful movement, and one hour before you lose consciousness. "Survive the first minute," he says, and you're on your way to saving your life. The most immediate danger comes from what's called cold shock in the first minute. This includes a gasp reflex followed by uncontrolled breathing known as hyperventilation. Your first goal is to fight the panic and get control of your breathing. Next, you've got ten minutes to move--swim to safety and crawl out of the water. After ten minutes, your muscle and nerve fibers get so cold that they don't function anymore. If you're running out of time and can't climb out, you should try to freeze your arms to the ice so that when you eventually lose consciousness in one hour, you won't sink to the depths.
If you've got some extra body fat, you're in luck. The heavier you are, the more time you've got in the cold. For a slight, lean person, hypothermia can set in after forty minutes in forty six-degree Fahrenheit water. At 190 pounds and more than six feet tall, Giesbrecht says it takes his body about an hour to become hypothermic at this temperature. Babies, children, and small adults are especially vulnerable because they lose heat faster than bigger people.
Myth #2: Most heat loss comes from your head. That's a falsehood perpetuated by mothers and grandmothers who want their children to wear hats. In fact, Giesbrecht says, only 8 to 10 percent of your heat emanates from your head. That leaves 90 percent from the rest of your body. In cold water up to your neck, even more heat escapes from the rest of your body, not your head. Shivering, he adds, is your body's way of turning up the thermostat, producing up to five times more heat than simply resting in a warm environment.
[Update: Commenters voice a lot of disagreement with this point. But researchers at the Indiana University School of Medicine studied the issue and found the head/heat loss myth probably originated in a US Army Field manual. Obviously, this doesn't mean you should leave your head exposed -- it just means covering your head shouldn't be your primary or sole focus. In the words of the researchers: "Any uncovered part of the body loses heat and will reduce the core body temperature proportionally. So, if it is cold outside, you should protect your body. But whether you want to keep your head covered or not is up to you."]
Myth #3: Hot drinks help beat the cold. In fact, Giesbrecht says, any drink with a lot of sugar will make a bigger difference. "The heat in drinks has mostly a psychological benefit," he explains. "One or two cups of warm fluid won't harm you very much." But sugar helps a lot, providing fuel for the body to generate heat and fend off the cold. If you're tempted to drink booze to warm up, remember that alcohol dilates or expands your blood vessels near the skin. That means more blood closer to the cold. You may feel warm and toasty, but you're actually losing more heat.
Myth #4: Blow on your hands to keep them warm. Bad idea. The moisture in your breath will only make your hands colder and increase the risk of frostbite. The better choice: Stuff your cold hands under your arms or between your legs.
Myth #5: Stay warm or you'll catch a cold. Exposure to cold weather doesn't make you sick. Exposure to sick people makes you sick. The main reason to stay out of the cold is because of the dangers of hypothermia, not the risks of a runny nose.
[Update: A number of commenters have challenged this point, offering personal experience as evidence along with this link to an interesting article summarizing the vast and contradictory research on the topic. I stand by the main point: Cold weather doesn't cause colds; exposure to sick people causes colds. The greatest danger of prolonged exposure to cold weather is hypothermia, not a rhinovirus.]