Read Outdoor Action Guide to Hypothermia & Cold Weather Injuries (PDF) from Princeton University for detailed information on hypothermia or check out their website. Do an Intenet Search on "Hypothermia" to find additional material.
Noted thermophysiologist (a scientist who studies human response to cold) Gordon Giesbrecht, Ph.D. teaches at the University of Manitoba and combines well-published research with extensive Arctic expedition experience, and a passion for educating people on hypothermia, frostbite and cold weather survival. Dr. Giesbrecht, who Outside magazine called "Dr. Popsicle," makes available training materials at www.coldwaterbootcamp.com.
Giesbrecht’s research and experience challenges some common assumptions about hypothermia and cold weather physiology. For example, many people believe that if you fall into cold water, you are almost immediately hypothermic. Not the case, says Giesbrecht, who has measured the response to cold on himself. He has lowered his body temperature to hypothermia 37 times during his research.
When we immerse ourselves in cold water, we immediately gasp and breathe rapidly. Any of us who have accidentally turned on the cold water in the shower knows the response. But there is great danger if our head goes underwater and we panic and inhale water. We might drown. The key, according to Giesbrecht, is understanding this response and controlling our breathing. It’s important to try to tread water slowly. Grab the edge of your boat or the ice and keep your head above the water. After a minute or two, your gasping should subside and, as your skin becomes numb, the intensely uncomfortable cold sensation should wane.
We have another 10 minutes before our muscles become too cold to move effectively. We could use this time to get out of the water, or to secure ourselves against drowning. Giesbrecht gave examples of people who have left on their wet clothing, letting it freeze to the ice to prevent them from slipping beneath the surface of the water. He also demonstrates how to properly exit an icy pond or lake by rolling and crawling to distribute your weight, rather than standing.
It’s another hour until our body temperature drops far enough to make us critically hypothermic. The scientist’s simple message is "1 minute, 10 minutes, 1 hour." We need to control our breathing and survive the first minute. Then we have 10 minutes to move carefully and thoughtfully, and an hour before we become gravely hypothermic. Knowing this, while we still need to promptly treat hypothermia, we don’t need to panic.
Addressing another myth, Giesbrecht notes that we don’t lose most of our heat through our head and neck. The head and neck are only 10 percent of our body surface area and are no more efficient at losing heat than the rest of our skin. This doesn’t mean it’s not good advice to wear a hat, scarf or hood when you are cold, just do so to insulate exposed skin, not to support a myth about high heat loss through our heads.
National Outdoor Leadership School's Wilderness Medicine Institute instructors have experimented with several ways to warm test volunteers. They found that "the hypothermia wrap" they teach is a sound field technique. For this kind of situation, here are some ideas:
Place the shivering patient in dry sleeping bags and wrap the bags with a plastic tarp to keep the insulation dry and reduce heat loss. Hot sweet drinks provide calories to fuel the shivering, which will warm most patients.
Get wet clothing off the patient. There is a fear that exposing wet cold people to the air when removing their clothing will quickly cause their temperature to drop. Giesbrecht commented that it takes a while for people to become hypothermic. As long as we remove wet clothing quickly and without jostling the cold patient, they are better off with dry insulation.
These instructors also explored placing the hypothermic patient in the sleeping bag with a warm naked rescuer. They found that this isn’t much more effective than the simple hypothermia wrap. A cold patient doesn’t absorb much heat through their skin. The rescuer is really only a source of heat to warm the sleeping bag and may be more valuable on the surface—making camp and hot drinks, cooking dinner, and making sure everyone else on the expedition is safe and sound.
To learn more about Dr. Giesbrecht’s work, click here.
Download Cold Water Boot Camp: Knowledge Translation from the Lab to The Living room (PDF) for more information about the instructional material offered by Cold Water Boot Camp.