(ABC News) -- With temperatures in the single digits in many parts of the country and wind chills whipping into the minus degrees, you'd probably prefer to be inside. But if you have to go out, proper attire might be a matter of life or death.
"You'll stay warmer wearing three thinner layers rather than one big, bulky one," advised David Moldover, an outfitting guide for Eastern Mountain Sports in New York City.
What is the polar vortex?
Here Moldover takes you through how to dress every inch of your body to stay toasty warm until this Polar Vortex passes.
Start with your skin
First, moisturize everywhere to prevent dry skin, including a balm for your lips. If you're spending extended time outdoors, don't forget sun glasses and sunscreen for the exposed parts of your face. Even in these frigid temperatures you can still burn, especially on a sunny, windy day if there is a lot of snow or ice to reflect UVA rays.
Wear a base layer
The layer closest to your body should fit tightly enough so it traps warm air next to the skin but loosely enough so it can still breathe and "wick away" perspiration. Choose a thick base layer if you are spending a lot of time outdoors and not moving around much, like sitting in the stands at a game. The average Joe who walks in and out several times a day can go with a mid-weight fabric to avoid overheating when indoors. Outdoor exercisers should choose a thin garment.
There are two schools of thought on what material makes the best base layer. Synthetics are warm and stay dry but tend to stink. Marino wool can be a bit itchy and holds onto moisture. But it dries quickly and doesn't readily pick up body odor.
Add a middle layer
This is the insulation layer that retains the warmth of your body heat. A sweater, down vest or light synthetic jacket works well.
Finish with an outer layer
Besides warmth, you want to make sure your outer jacket is wind and waterproof. If you have an ordinary down jacket, put a rain coat or wind breaker over the top of it. Or, wear a jacket with a synthetic outer material that repels wind and water.
Don't forget leg covering
Don't forget to slip some long johns on beneath your pants. In general, any lower-body undergarment can be on the thin side since the large muscles of the legs generate more heat than other parts of the body. On super windy or snowy days, consider wearing snow or wind pants on top.
Cover your head
You lose a lot of heat through your head, so wear a hat that covers your ears. Marino wool is best because it's lightweight, breathable and won't dry out your scalp. Don't forget to wrap a scarf around your neck. You can also use it to protect your face from wind and bitter cold.
Protect your hands
Mittens allow your fingers to rub together, so they tend to be warmer than gloves. However, you may have to take them on and off a lot to work your phone or grab your keys. Whatever your personal preference, you want to cover your hands with something lightweight, waterproof and wind-resistant to stay warm and dry, so here again, synthetics or wool are good choices.
Warm up your feet
All the layering and bundling up in the world won't keep you comfy if your feet are like ice cubes. That's why a good wool or wool-blend sock is essential. Consider adding a thin sock liner beneath bulkier socks too. Wear waterproof boots on slushy days to prevent seepage. Otherwise, regular shoes or boots are fine.
Make sure you can still wiggle your toes with all the extra layers. Otherwise your feet will freeze up from lack of circulation. Consider wearing removable spikes to navigate icy patches and stash an extra pair of socks in your bag just in case your feet get wet.
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