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Lost in The Snow
Former Olympic hockey player Eric LeMarque was snowboarding alone in the Sierra Nevada in 2003 when thick fog settled around him, limiting his vision to 10 feet. Soon he was lost in the snowy wilderness with no food and a dead cell phone. He wandered through 15-foot snowdrifts in freezing temperatures for seven days before National Guard searchers found him.
When exposed to bitter cold, your body shivers, and this involuntary movement creates heat the same way exercise does. If you stay in the cold and your body temperature continues to drop, shivering will stop when the muscles no longer have enough energy to move, says David Richard, a professor of biology at Susquehanna University in Pennsylvania. He teaches the course “Exercise and Extreme Physiology” and is an authority on the processes that sustain life under extreme conditions—and on what happens when the human body is exposed to more than it can withstand.
After prolonged exposure to intense cold, Richard says, your body’s chemical reactions begin to slow until they generate too little energy for your muscles to work. By carefully regulating blood flow, your body will protect your key organs while preserving your extremities—at least for a while. In the cold, blood is generally directed to the core of the body and flows only intermittently to the extremities to bring oxygen to cells there. After prolonged exposure to cold, blood travels only to the most essential parts—your brain and heart. As severe hypothermia sets in, these organs may be the only ones left functioning.
In a 2000 paper in The Lancet, a team of Norwegian doctors described resuscitating a woman who had been trapped in icy water for 40 minutes and whose core temperature had dropped to 57 degrees. This is very unusual; most people do not survive a core temperature below 70 degrees, Richard says. Still, upon finding a victim, rescue workers make no assumptions (“They’re not dead until they’re warm and dead,” the saying goes.) You may be breathing so imperceptibly that you look dead, but you might survive if an alert emergency worker warms and resuscitates you.
Frostbite occurs when the temperature in your tissues falls to one or two degrees below freezing. As the water in your tissues turns to ice, salts in body fluids and cells become more concentrated, interfering with proteins so much that the cells die. At the same time, the sharp edges of microscopic ice crystals can tear cell membranes. Don’t rub your frostbitten skin: The force of rubbing can shred already-damaged areas.
Falling Out of a Plane
In 1942 a Soviet pilot named I. M. Chisov plunged 22,000 feet without a parachute after bailing out of his Ilyushin 4 bomber. German pilots had attacked Chisov’s plane, and he didn’t open his chute because he was afraid it would allow his attackers to find him. He landed on a snow-covered slope and rolled downhill, badly hurt and unconscious—but alive.
According to aerodynamics experts, a skydiver without a chute reaches a terminal velocity of about 120 miles per hour after dropping roughly 500 feet. That actually isn’t any faster than the speed you’d reach if you fell from a moderately tall building. “But it’s not falling that kills you; it’s the landing,” Richard says: The abrupt pressure of an impact is likely to break open blood vessels such as your aorta, damage internal organs, and shatter your bones.
The worst thing to hit is a hard surface that brings you to a halt almost instantly. If you land on snow (like Chisov) or hit something that gives way, such as a skylight (as happened to U.S. Air Force Sergeant Alan Magee, who survived a 20,000-foot drop into a French train station in 1943), you will suffer less damage. In such a situation, it is the ability of the bones of your skull and spine to withstand the impact that can potentially preserve your life, according to a report conducted by the Federal Aviation Administration.
Struck by Lightning
Roy Cleveland Sullivan, a forest ranger in Virginia, was hit by lightning seven times in his 71 years. The lifetime odds of being struck by lightning are higher than you might think—about 1 in 5,000—but it still takes bad luck (and a dangerous lifestyle) to be hit more than once.
About 80 percent of people who are struck are not killed. When lightning strikes, less than 1 percent of the bolt’s current flows through your body, according to a recent study in the Journal of Electrostatics. The rest travels over the surface of your skin, which has a lower resistance to electricity. Lightning bolts, which typically pack a 100-million-volt wallop but are only about as wide as a pencil, may burn your skin or leave featherlike markings called Lichtenberg figures. These form where electric current or the resulting shock wave in the body bursts capillaries in your skin. The burns are not usually severe, however.
