February 25, 2020
Categories: Travel Tips
When the weather outside feels almost arctic, it can be a challenge to maintain a normal body temperature of 98.6 degrees Fahrenheit (37 degrees Celsius). But that’s what you need to do to avoid hypothermia, which occurs when your core body temperature drops to 95 degrees (35 C).
When you step outside appropriately bundled up for your cold-weather adventure, how do you maintain the body heat you desperately need?
“It’s easier to stay warm than get warm,” said Harding Bush, associate manager of operations at Global Rescue.
How We Lose Heat
Bush, a 20-year special operations forces veteran with an additional nine years of experience in international travel security, knows how to survive in extreme environments.
“It is essential to understand how our bodies lose heat,” Bush said. “This understanding will enable you to avoid cold-weather injuries and make the best use of cold weather clothing and equipment.”
According to Bush, heat is lost through convection, conduction, radiation, evaporation and respiration.
- An example of heat loss through convection is the wind moving across bare or poorly protected skin. This type of heat loss is prevented with windproof (or waterproof) outer layers of clothing.
- Physically touching or contacting a colder surface creates heat loss through conduction. A foam pad between your sleeping bag and the tent floor is a method of preventing heat loss through conduction.
- When our bodies are warmer than the air around it, we lose heat from our bodies trying to warm the colder air. This is prevented through an insulating layer of clothing when the radiating heat is trapped and retained in these layers to keep us warm.
- When we are active, perspiration evaporates as a heated vapor, which reduces body heat and accelerates radiation. This is prevented by managing the level of exertion during an activity and taking off layers to reduce heavy perspiration. This is also why many cold-weather outer layers have zippers under the arms and along the core, allowing perspiration to vent off in a vapor.
- We also lose heat through respiration. The more we exert ourselves, the faster we’ll lose heat once the activity stops.
Seven Cold Weather Combat Tips
All these ways to lose heat can work together, making your job to stay warm more difficult. Foil frostbite and halt hypothermia by following these cold-weather combat tips from Global Rescue’s outdoor experts.
1. Start Cold
Your body will warm up during outdoor exercise and sweat in an effort to cool down. But sweating isn’t a good thing — “it will zap body heat,” Bush said. Those wet layers will quickly make you feel cold again.
He suggests starting cold and adding or adjusting layers to reduce the likeliness of overheating. When you stop, immediately add a warming layer to hold in heat.
“I always have a fleece or a light down jacket and hat in the top compartment of my backpack for this reason,” Bush said.
If anything gets wet or sweaty, change clothing to prevent loss of body heat. Store wet gloves in a zippered pocket that doesn’t make contact with your body. Global Rescue offers more winter clothing advice here.
2. Keep Moving
A human’s metabolism continuously produces between 50 and 100 watts of heat and can release more during physical activity. Small movements and stretches will keep circulation moving and increase your metabolism.
If you’re skiing or snowshoeing, you won’t have to worry about movement for warmth. But if you’re stuck in a blizzard, it will be key to survival. Wiggle your fingers and toes, clap your hands, bend and unbend your arms — keep the blood circulating without breaking a sweat.
3. Eat Something
Eating also increases body temperature, so snack away during your outdoor activity.
Outdoor experts swear by root vegetables, complex carbs (oats and brown rice), fatty foods that take longer to digest (chocolate, cheese, nuts) and simple foods (granola or energy bars) that combine the nutrients your body needs.
4. Drink Water
You usually don’t think of dehydration as a cold weather hazard. In the winter we tend to go longer periods without drinking water and our bodies will quickly get out of balance. That imbalance will decrease metabolism and slow the flow of blood to extremities. Your body will tolerate the cold better if you stay hydrated.
5. Protect Extremities
Although it is a myth that you lose all the heat from your head, it is a fact that you will lose heat from any exposed surface — head, feet, hands, neck, the space between your sunglasses and your hat.
Gearjunkie.com suggests wearing wraparound sunglasses and well-fitting goggles to cover more of your face. Orvis recommends a two sock system: a lightweight synthetic liner sock and a heavyweight wool sock.
To make sure your hands are protected, Bush recommends wearing glove liners underneath mittens.
“Say you need to take off your mittens to tie your boots,” Bush said. “You won’t want to do this with bare hands as blood rushes to extremities to add warmth. Thin glove liners will keep you from exposing bare skin if you need to remove heavier gloves or mittens.”
6. Take A Break (Or Two)
If you are going to be outdoors for a long period of time, schedule time for breaks.
“Being tired makes you cold. Your body has to work harder to keep warm,” Bush said. “Take off your backpack and rest.”
It’s also a good time for clothing changes — adding or removing layers and adjusting goggles or a face mask — and fueling up with a drink of water and a snack.
“You are in the outdoors to enjoy the environment and the activity — but it won’t happen if you are too cold, too wet, too dry, too hot, too hungry or too thirsty,” Bush said.
7. Guard The Group
If you are with a group, make sure every group member is on the same schedule with the same breaks.
At the beginning of the break, “it is vital to add an outer or insulating layer, such as a down jacket with a hood or a wool hat, as soon as we cease activity,” Bush said.
At the end of the break, before you take off those layers, “ensure everyone is ready to step off together. Don’t be the person putting the stove away when the others have already removed layers and are beginning to shiver because they are waiting for you,” Bush said. “As you are getting ready, communicate ‘We are stepping off in five minutes.’ This allows everyone to be ready at the same time — and stay as warm as possible.”
Whether you’re seeking outdoor advice, like the warning signs of frostbite, or need immediate medical or security assistance, Global Rescue operations centers are staffed 24/7/365 to assist members with any travel request.
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