Are you prepared for hypothermia?

Posted Jan. 24, 2011, at 10:53 p.m.
Last modified Jan. 29, 2011, at 12:37 p.m.

The group of college students prepared well for their winter camping trip, a loop through the high peaks of the Adirondacks. But they failed to notice when one of the young campers skipped breakfast, lunch and dinner. It wasn’t until she crawled into her sleeping bag early in the evening and wouldn’t wake up that they called for help.

The nearest park ranger, Ben Woodard, hurried to their campsite.

“It was a very scary situation,” Woodard said in a recent phone interview.

Though her breathing and pulse were nearly undetectable, he knew that she was hypothermic and might be revived if he acted quickly.

Her body was too fragile to move on a sled, so they carried her a mile to the nearest cabin, still 6 miles into the backcountry.

Woodard made the cabin into a rainforest, heating it up with humidified air, and then set to work giving her mouth-to-mouth respiration all night, heating her up from her core.

At about 3:30 in the morning, she responded to pain for the first time. By 5 a.m., she spoke to them and began accepting food and warm fluids.

“Her college leader had an urban medical background, but this was a group dynamic thing where he didn’t notice the signs,” Woodard said.

Woodard was a seasonal ranger for 26 years in wilderness areas from Alaska to Maine before he became Baxter State Park chief ranger in January 2009.

“Hypothermia is a challenge to the body to maintain the body core temperature,” Woodard said. “It’s the cooling of the body core. That challenge happens through cold temperature, moisture and lack of calories that are needed for the body to maintain metabolism.”

Rangers and rescue teams at Baxter State Park carry insulating emergency blankets and a waterproofing layer year-round.

“Hypothermia is always a thought in our minds,” Woodard said. “We have below-freezing temperatures in the summer as well.” Even if the temperature doesn’t go below freezing, there’s still the possibility of people going hypothermic.

People often hike without a windproof layer and don’t know that temperature drops and wind speed often increases as you gain elevation. An injured person is often immobile and covered in sweat, increasing the likelihood of the body’s core temperature dropping.

“It can happen any time the body is challenged to maintain its heat,” Woodard said.

Winter hikers should have the awareness in the back of their minds that they’re going to be challenged by the cold. They should look out for each other, said Woodard, and be aware of the signs of hypothermia.

What’s alarming is that a person with hypothermia isn’t usually aware of it because the symptoms often begin gradually and hypothermia causes confusion or lack of self-awareness.

Symptoms of hypothermia usually occur in a progression. They start with involuntary shivering and loss of motor skills. Blood vessels shut down in the hands and feet. As body core temperature falls below 95 degrees, the shivering becomes violent. The person may slur speech or mumble, display illogical behavior, loss of emotional cognition or fight consciousness. Below 92 degrees, the effects become life threatening, shivering stops, muscles become rigid, pupils dilate and pulse drops. By 86 degrees, the person is in a state known as the “metabolic icebox.” Breathing becomes shallow and erratic, consciousness is lost and the heart becomes vulnerable to deadly arrhythmia.

Winter park use up

“Our winter use [of the park] has really increased because we’ve made it much easier for people to come in and enjoy the wilderness in the winter months,” Woodard said. “And all of those people still have to be prepared.”

Woodard says that people should always embark on a day hike ready to spend the night in the outdoors, equipped with extra clothing, water, food and a way of heating that food.

Jack Drury, former president of the Wilderness Education Association, calculates a maximum of 4,200 calories per day as a nutritional requirement for college students during strenuous winter expeditions in the Adirondacks.

“I think about metabolism in the body almost like a fire,” said Woodard. “Simple sugars and candies are the kindling. Carbohydrates such as snack bars are more like sticks. And then fats and proteins are logs and maintain heat for a long time.”

A 10 percent hydration decrease will cause a 30 to 40 percent decrease in thermal control, according to Dr. William M. Forgey’s book “Hypothermia.” Daily water requirement is calculated at 1.5 liters, but dry, cold weather increases the loss of moisture through respiration. Keep in mind that thirst lags behind actual water requirements.

Preparation isn’t all about what you carry in your pack. Leave an itinerary at home before you go so and make sure to sign the hiking register at the trailhead so rescue teams know who to look for and where to look.

But sometimes, even if prepared, accidents happen. People hike, ski, fish and snowshoe alone. Acute hypothermia develops in two hours or less. This usually happens when a person falls through a frozen lake or into frigid ocean water.

“Moisture [exacerbates] that body core cooling, so if someone falls through the ice or into the ocean, it happens a lot quicker,” Woodard said.

One man known for his studies of the human response to freezing water is thermophysiologist Gordon Giesbrecht, whom Outside magazine called “Dr. Popsicle.” He has lowered his body temperature to hypothermic levels 37 times during his research and has given demonstrations of the effects of hypothermia by intentionally falling through thin ice and remaining in the water until nearly unconscious.

His message is “1 minute, 10 minutes, 1 hour.” You need to control your breathing and survive the first minute after falling in ice water until numbness sets in. Then you have 10 minutes to move carefully before your muscles become useless. You should use this time to try to leave the water by treading water and lifting yourself onto surrounding ice, then rolling and crawling to land. If you can’t, keep your head above water, call for help, and if all else fails, place your arms on the surrounding ice so they freeze there and keep you afloat if you become unconscious. You have an hour before becoming acutely hypothermic.

The young woman in the Adirondacks is an example of a person developing chronic hypothermia, a lowering of the core temperature below 95 degrees Fahrenheit over a period of six hours or longer due to lack of insulation and calorie intake. This gradual development often progresses undetected. Preparation and being attentive to people in your group can prevent this type of hypothermia from developing.

To watch Dr. Gordon Giesbrecht, also known as “Dr. Popsicle,” teach about survival after falling through ice in the series “Survival in the Ice,” watch this video.

How to help hypothermic people if medical care is not available:

  • Get the person into a warm shelter. If pre-made shelter can’t be found, insulate the person from the ground with a waterproof layer and shield the person from rain and wind.
  • If the person is wearing any wet clothing, remove it.
  • Wrap them in an insulating blanket. The goal is to gradually warm the center of the body first — chest, neck, head and groin.
  • Warm beverages can help increase body temperature.
  • If in an enclosed shelter, heat up and humidify the air.
  • After body temperature has increased, keep the person dry and wrapped in a warm blanket, including the head and neck.
  • Get medical attention as soon as possible.
  • A person with severe hypothermia may be unconscious and may not seem to have a pulse or be breathing. CPR should continue while the victim is being warmed, until the victim responds.

To prevent hypothermia:

  • Continuously eat a variety of food all day and keep hydrated.
  • Have a layering system of dry clothing including a waterproof, windproof layer and larger insulating layer for when you aren’t moving.
  • Don’t travel across thin ice and protect yourself from moisture.
  • Keep your skin covered, including your head, in cold temperatures.

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