Dressed only in a bathrobe and sandals, Trent Yackimec sprinted from the Mechanical Engineering Building to the Quad, in temperatures of minus 20 degrees Celsius. The masochistic dash was part of a stunt for Engineering Week. Good thing there was no wind, the fourth-year engineering student said, "the only part of me that got cold was my toes."
Yackimec's mad dash was probably what staved off the first sting of cold, says Dr. Larry Wang, professor of biological science. "In our body, we have a furnace-our muscles. The muscles contract, shiver and shake. By exercising, heat will be produced as a byproduct of muscle contraction."
Exactly how a body stays warm is clear, Wang says. "Body temperature is maintained through two processes: one is heat conservation and the other is heat production." In other words, you can bundle up against the cold or exercise to produce your own heat. Science has long understood how a body keeps warm, but until recently, did not understand why it sometimes fails-and people die of hypothermia. The human body has plenty of metabolic fuel reserves, particularly fat, Wang says. "One pound of fat can give you 4,000 calories." Even a person of normal weight has enough fat to generate sufficient heat to keep their body warm forever. But for some reason, the body shuts down in extreme cold.
Dr. Larry Wang
"Hypothermia happens when the heat you lose to the environment exceeds the maximum heat production you can generate," Wang says, "It's defined clinically when the core temperature is below 35 degrees Celsius." After losing just two degrees, symptoms of hypothermia appear: shivering, loss of muscle coordination, hallucinations and behavioral changes. And once hypothermia sets in, Wang says, "it's like a downward spiral towards death. As the body cools, your ability to generate heat is reduced because a colder body doesn't generate as much heat as a warmer body." Shivering stops, the body cools further and eventually the victim's heart fails.
"There's very little you can do to get yourself out of it. It is very dangerous," says Wang. And its onset is imperceptible. "You feel cold, lethargic, you fall asleep and then you die. It's not like you have a warning like a sharp pain. It's peaceful." Discovering why people with enough fat reserve freeze to death was the focus of Wang's cold tolerance study. Student volunteers-dressed in shorts and T-shirts-spent up to three hours in a room at minus 10 degrees with a blowing fan reducing the temperature to minus 20 degrees.
The volunteers alternated between rest and exercise, either on a treadmill or a stationary bike. Wang measured their deep core temperature and various skin temperature from the forehead to the chest, thigh, calf, and ankle; and recorded their heart rate, blood pressure and respiratory rate. He also took blood samples to assess the body's physiological response to severe cold.
Wang wanted to know whether we have the capacity to generate enough heat to fight cold. "The experiments done on the human volunteers answer that question very clearly, yes, we do have a very good furnace.We should have no problem whatsoever producing enough heat to keep the body warm. We shouldn't be freezing to death."
The body's furnace is adequate for generating heat and our cardiovascular and respiratory system supply us with sufficient oxygen to fuel cells. "So we have a big furnace, good oxygen supply, what is the problem?"
The problem, he found, is that we have a bottlenecking of our "fuel lines." Something prevents the liquidation of fat into fuel during extreme cold. Instead of working overtime to heat the body, the furnace shuts down, conserving when it should be burning.
Wang's research identified a molecule called adenosine; the metabolic end product of the energy 'cash' your body spends to stay warm. That energy cash is called Adenosine Tri-Phosphate, or ATP.
"ATP is the cellular form of cash," Wang says, "no ATP, no work!" Adenosine is like the cash-register receipt or proof of the currency you've spent. And just as a tally of what you've spent can cause alarm and a resolve to spend more wisely, adenosine acts a signal to our bodies to preserve precious fuel. Without fuel, muscles stop contracting and the body cools down.
Wang's much publicized "Cold Buster Bar" was developed to suppress adenosine so the body's fuel line would remain open.
When students in the cold room ate the bar, their cold tolerance improved 50 per cent.
Since its introduction to the marketplace in 1991, the Cold Buster bar has earned an outstanding food product of the year award (Gordon Royal Maybee Canadian Institute of Food Science and Technology), and Wang has received an ASTech Award for Innovative Technology.
The Cold Buster Bar has since been modified to improve its taste and texture and is now called the "Access Bar." The Access Bar and a similar "Canadian Fat Burner" bar have been marketed in North America and Southeast Asia. By helping release stored fat, these bars can enhance physical activity as well as keeping the body warm.
Just the thing if you're venturing into the woods or dashing across campus in your bathrobe on a frozen morning.
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