Why Does Layering Keep You Warmer


Layering To Stay WarmWhy Does Layering Keep You Warmer in The Winter?  Very important information! Layering keeps you warmer in the winter because it traps body heat where you need it, wicks away moisture and protects you from wind and wet weather.  Layering save lives.  In some cases, layering may be the difference between enjoying a back-country ski trip or needing a helicopter rescue.

Layering could also mean the difference between losing your fingers to frostbite or keeping them warm and writing that book you’ve been talking about for decades.  According to the CDC, more than 700 people die every year from hypothermia.

In many of those cases, exposure to cold weather while wearing improper clothing was a contributing factor. To be most effective, layering needs to follow a general set of guidelines.  How you layer your clothing is also just as important as the fabrics those layers are made out of.

As you’ll soon learn, cotton is not as effective as keeping you dry as merino wool and synthetic fabrics.  In fact, wearing a cotton pair of socks or long johns is setting yourself up for a really cold and miserable adventure.  I’ll get into that in more detail in a bit.  Bottom line, layering is critical to stay dry and staying warm.  Without the proper layers, you may find yourself knee deep in fresh powder with frigid feet.

How Does Our Body Lose Heat?

How We Lose Body HeatGreat question.  To really understand why layering keeps you warmer in the winter, we first need to take a look at how we lose body heat. I promise there won’t be any pop quizzes! When your outside in sub-zero or freezing temperatures, we have to work hard to hold onto our body heat.

When the human body is exposed to temperatures colder than our toasty 98.6 degrees, the heat naturally wants to radiate or escape unless we trap that heat close to our body. Our bodies lose heat a few different ways: respiration (our breathing), conduction (touching a cold surface), convection (wind), evaporation (sweat, water) and radiation.

Conduction

Conduction happens when you grab a cold ski pole with your bare hands or sit down on a hard pack of snow while eating lunch at the top of a mountain.  When your warm hand touches a cold surface, you lose body heat.  Yikes! To cut down on how much heat you lose from conduction, you need to protect your hands, feet and body by wearing layers! Layers protect your body from the unforgiving weather of the winter and prevent your body heat from creeping out into the cold!

Convection

Convection is basically the process of losing body heat from wind.  Wind is a thief of body heat and it should have a warrant out for its arrest.  Clearly, we can’t arrest wind.  But, you get my point- I hope! We can lose a lot of body heat from wind. In fact, some outdoor experts believe protecting yourself from the wind is a top priority in staying warm. If you’re not wearing a windproof barrier to prevent the wind, you could easily get chilled and your body temperature may drop rapidly.

Have you ever noticed you feel nice and warm and then a sudden burst of wind whips by out of nowhere? Brrrr. That wind is taking your body heat and leaving you feeling cold and vulnerable.  Layering prevents that wind from reaching your precious body heat.  Layers are like a lock on your front door of your house.  That lock, is the first line of defense against criminals breaking in and stealing all your jeweler and flat screen tv.  A nice windproof outer layer is the first line of defense in keeping the wind out and keeping your body heat where it belongs…. close to your body!

Evaporation

Whether your hiking to the top of a glacier or making fresh tracks down the backside of Sun Valley on a bluebird day, you’re most likely going to be working up a sweat.  Layers wick away all that moisture and keep your skin nice and dry.  When you’re outside enjoying all the great winter time activities, stay drying is crucial to staying warm.  If you get too sweaty and you’re wearing cotton- which absorbs water, your clothing could actually be working against you.

In fact, when cotton gets wet it draws heat away from your body and your temperature drops quick! Managing moisture is important is staying warm, dry and alive during the cold winter months.  Layering works wonders when it comes to keeping moisture at bay and insulating you all at the same time!

Radiation

As I mentioned earlier, our bodies naturally want to release all that body heat when exposed to colder temperatures.  This is about the time you should break out your down jacket.  To cut down on heath loss through radiation, you want to insulate your body will a nice fleece, down or wool coat.  This middle layer is referred to as the insulating layer.  We’ll get into the specific function of each layer in a just a few minutes.  Stay with me, here!

What Are the Basics of Layering?

There are basically three layers you should always have on when out and about enjoying the nice cold weather.  These tips not only apply to hunters, ice fisherman, skiers or hikers.  Layering should be considered when you’re going to be outside for long periods of time.  That late fall football game in Wisconsin is a great place wear layers! Signing Christmas carols around the neighborhood in December? Layering is for you too! Ringing in the new year in Times Square? Yep, I’m talking to you too! Anyone who is outside in cold temperatures will most certainly benefit from wearing layers.

Base Layer

Base Layers

The sole function of a base layer is to keep moisture away from your body.  As I mentioned earlier, staying dry is really important in staying warm.  As soon as you start to feel wet and your clothes are soaked in either sweat or snow, your body temperature drops like the crystal ball on New Year’s Eve.  That fast. Seriously.  The base layer should fit close to your body- not too snug and not too tight. Base layers are referred to as long johns or long underwear.

Nearly every outdoor gear store will sell high quality base layers.  While moisture management is the main function of the base layer, it also does a really good job of keeping a thin, warm layer of air close to your body. You’ll find you really need this layer of warm air when your start to get into some wicked winter weather. Hang onto this warm air at all costs!  See also our article entitled “Top 24 Base Layers For Winter Camping“.

When shopping for a base layer, pay close attention to the fabric.  I’m a big fan of merino wool.  Merino wool is not like what your grandma used to send you for your birthday.  You know that hand knitted wool sweater that always made you break out into a bright red rash right around your neck? That one.  Merino wool is nothing like that.  You get all the warmth and moisture management with merino wool, without the weird rash. Pretty cool.  Merino wool is on the expensive end of base layers, but you can often find budget friendly merino wool when it’s blended with synthetic material like nylon and lycra.

Each outdoor gear brand carries its own propriety blend of long johns.  If the label indicates merino wool, you’re going to be warm and you’ll keep that sweat under control.  Synthetic fabrics also do a really great job of keeping the moisture away too. It’s a matter of preference, I guess.  My favorite pair of thermal long johns are made with a synthetic blend of polyester and spandex.

The price range varies dramatically for base layers.  But, to be honest, you get what you pay for.  I have a pair of $120 Capilene long johns that at more than 15 years old and I still wear them every ski season.  They’re the warmest and most durable set of long johns I’ve ever owned.  When in doubt, I choose quality over price.  If you’re budget allows for it, choose a pair of thermal underwear that you know will last! A few trusted brands: Fortress Clothing, REI, Patagonia, Cabela’s, Marmot, North Face and Arc’teryx.

Base layers also come in a variety of weights.  The heavier the long johns the more insulation.  While this is important in staying warm, it’s not the sole function of the base layer.  Remember, focus on that moisture management! However, if you are going to be hiking and camping in January along the Pacific Coast Trail, which I don’t recommend by the way, you may want to pack a light weight base layer for hiking and put on a heavier pair for sleeping.  Think about what you’ll be doing outside and what the weather will be like and that will help you narrow down the best type of long johns for you!

Middle Layer

Mid Layers

With the base layer working hard at keeping you dry, the middle layer steps in to insulate your body and keep that heat where it belongs. The main function of the middle layer is to insulate.  Down jackets, vests and fleece coats are all great choices for a middle layer. However, you don’t want to get too hot! This is why you also want the middle layer to be breathable. What does breathable even mean? To be honest, when I first started researching about winter survival clothes, outdoor experts were always recommending every coat and layer to be breathable.

Turns out breathable means the coat allows body moisture to escape-this is really important to staying warm.  The base layer wicks the moisture away from your body and the middle layer lets that sweat pass through all while keeping you warm.  This is why layer is so important!! Each layer works together in unison to maintain your body temperature and keep the harsh weather away!

You have lots of choices when it comes to middle layers.  Down is a great option for a middle layer because it can be fairly light weight and provide a lot of warmth factor.  Down is typically more expensive than other materials, such a s fleece or merino wool.  Another downside to down: when it gets wet, it loses its insulation power. To prevent your middle layer from getting wet you need an outer layer! I’ll get to that soon!

Fleece is also a great option if you want a cozy, soft and more budget friendly middle layer.  Fleece jackets or pullovers are made out of polyester fleece. This type of material has a really great insulating value- which basically means it will keep you nice and warm. However, like down, fleece doesn’t do a good job of keeping you warm when it’s windy or wet outside.  While fleece can dry out quicker than down, when it gets wet, it stops keeping you warm.  Bummer.   But, if you add a waterproof/windproof outer shell over the fleece you’ll be ready for whatever mother nature throws at you!

Merino Wool

Merino wool is also a really great choice for a middle layer! Merino wool works wonders when it comes to moisture management and keeping your body warm.  In fact, unlike other fabric, merino wool keeps you warm, even when it gets wet!  Merino wool is a great at keeping odor away too. So, if you are hiking for a few weeks or unable to shower for a few days, a merino wool middle layer may be the right choice for you.  Merino wool can be the most expensive of the middle layer choices, so it may not be for everyone’s budget.

If you’re in the market for a quality middle layer, expect to pay a couple hundred dollars.  All these layers can add up fast, I know! But, if you’re in the woods in the middle of winter and you’re starting to shiver, you’re going to wish you were wearing the best gear available.  While some circumstances may be out of your control when you’re enjoying the wilderness in the winter, being prepared and dressing in the right layers can make a difference!

Outer Layer

Columbia TurboDown Wave

The outer layer works in tandem with the base and middle layer to keep your body temperature a nice 98.6.  The outer liner Is your own personal shield against wind and water.  Think of the outer layer as body armor, protecting you against the cold! The main function of the outer layer is to repel the weather! Get it? The outer shell keeps you dry, allows for sweat to evaporate and keeps the wind from stealing your body heat.  When done right, all three layers keep you comfortable and alive!

When researching outer layers, you’ll most likely come across all sorts of phrases: waterproof, water resistant, windproof, soft shell, hard shell, vents and more.  What does it all mean? Waterproof means the jacket is designed to keep water from penetrating the coat and your middle and base layers.  You’ll know a coat is waterproof if its treated with a durable water repellent (DWR).  You know when it’s raining and the water beads up on the coat? You can thank DWR for that! Thanks, DWR!

Don’t confuse waterproof with water resistant- they’re not the same thing.  Water resistant coats are made of nylon/polyester and are typically designed for drizzling rain or walking near a waterfall.  Water resistant means the coat will only keep you dry in light rain conditions.  If that drizzle changes to a full-on hurricane, you’ll be soaking wet in no time.  Water-resistant coats are typically light weight and less expensive than waterproof coats. However, they won’t keep you 100% dry.

So, when choosing the right coat for you, consider the weather you’ll be encountering. What will you be doing? Are you going to be really active? Fairly sedentary? These are all great questions to ask yourself before deciding between waterproof and water-resistant.  Depending on what I’m doing, I’ll sometime bring both! Water-resistant coats are budget friendly and lightweight, so it’s easy to pack!

Make sure your outer layer also protects you from the wind.  Remember our lesson in how we lose body heat? Well, it’s pop quiz time.  How much heat do we lose from convection? According to medical experts, we lose about 10-15% of our body heat through convection.  Convection happens when the wind brushes past our body and takes all your heat! You don’t want the wind stealing your heat.  This is why it’s important to choose an outer layer designed to keep the wind away.

Outer shells also need to be breathable, especially if you plan on being active.  As you now know, the base layer works hard to wick away moisture.  All that sweat moves up the middle layer, where it evaporates, ideally, through the outer layer.  If all that sweat has no where to go, you’ll start to get over heated and then you’ll lose body heat. This is why it’s important that you choose fabrics that work with each other, every layer of the way!

Feet/Hands/Head

SmartWool Trekking Heavy Crew Socks

The same layering techniques we apply to keeping our body warm, also apply to our hands, feet and head.  Glove liners and sock liners are great at wicking away moisture and keeping your feet/hands dry.  Liners are also a really good choice to keep a warm layer of air close to your body. Make sure those liners aren’t too snug, because then you’ll lose circulation. Sock liners are designed to be worn with another pair of socks.  Glove liners should also be paired with an outer glove.  For ultimate moisture management and insulation, you’ll want to wear two layers on your feet and hands, and sometimes your head.  Wearing a hat reduces the amount of heat lost from radiation! It’s estimated we lose about 40% of our heat from radiation.

Fortress Classic Regular Mittens

When you’re out on a snowmobile in the middle of the woods, you can’t afford that kind of heat loss.  When choosing the best layers for your head, hands and feet follow the same guidelines I outlined above.  Avoid cotton like a cougar and her cubs in the Rocky Mountains. Instead, look for layers made with merino wool and synthetic blends.  After doing extensive research, I discovered a lot of liners are made with a blend of wool, acrylic and spandex.  This combination of fabric gives you warmth, moisture control and comfort all in one!

Sock liners should also fit snug, but not so much that you cut of circulation to your toes. Sock liners add an extra layer of warmth for particularly cold days.  Think of sock liners as a base layer for your feet.  There’s nothing worse that cold feet, two hours into a three-day excursion through Yellowstone in November.  Once you find a nice sock liner, add a pair of lightweight merino wool socks over them and try on your shoes.

Classic BalaclavaI always recommend people try on their liners with their socks and shoes before they hit the trail. This way if certain areas are too snug or rub in the wrong spots you can troubleshoot before you leave for your outdoor adventure.  There’s nothing worse than warm feet and a nasty blister to ruin it all.  A blister usually means you have to stop what you’re doing, take off your boots and socks and apply first aid.

While it feels good to tend to a blister, it also means releasing a lot of body heat when you take off your socks and shoes! In some cases, you may want to go with a slightly bigger boot, if you need a sock liner to go with your pair of socks!

It’s Easier to Stay Warm Than to Get Warm

If you’ve spent any time outside, you certainly have heard this phrase: it’s easier to stay warm than to get warm. This means it’s easier to keep your body heat than it is to try to generate body heat in cold weather. Layering helps you keep your body heat and prevents you from suffering from hypothermia and frostbite. When it’s freezing outside and you lose body heat, it can be exceptionally difficult to generate enough heat to stay alive. Unless, you are able to seek shelter or warm up by a fire, getting warm after being chilled can be very hard to do. This is why layering is so important!!! Layering saves lives!

Hypothermia

Hypothermia

Once your body starts shivering, you’ve already entered the beginning stages of hypothermia.  Hypothermia is a medical condition, where your body temperature is below 95 degrees. Our bodies function best at 98.6 degrees. Our bodies need a nice 98.6 degrees for our vital organs, such as our brain, heart and lungs, to operate at their fullest potential.  Once your core body temperature drops below 95 degrees, your body starts shutdown.  Appropriate layering keeps your body insulated and prevents your core temperature from dropping.  Without layering, you would lose all your natural body heat and you would be exposed to the harsh, unforgiving and potentially deadly weather conditions.

Our bodies aren’t designed to be exposed to cold temperatures for long periods of time. Layer adds extra warmth and keeps your body heat where it should be! As I mentioned earlier, wearing the wrong clothes can be a contributing to hypothermia.  If you’re outside for too long or you are not wearing the right layers, you will start to notice shivering, confusion and perhaps you’ll feel extra sleepy. Depending on the air temperature and wind speed, hypothermia can set in as quickly as 30 minutes after being outside!  That’s why it’s so important to wear the appropriate layers!

Outdoor survival experts say the beginning stages of hypothermia can be so subtle, people often don’t know their body temperature is dropping until its too late. Other signs of hypothermia include: slurred speech, confusion, clumsiness, low energy, sleepy, weak pulse and bright red skin.  Often people who suffer from hypothermia will take risks as well.  If you or anyone in your group exhibits any of these signs its critical to turn around and call for help. A person with hypothermia can decline rapidly.  If you can remove any wet clothing and try to keep them dry and warm until help arrives.

Layering is your best bet at preventing hypothermia or frostbite from setting in.  Layering keeps your body heat close to your core which keeps your vital organs functioning!

Frostbite

Frostbite

Frostbite is a medical injury to your cellular tissue.  Frostbite sets in when your cell tissue freezes. This freezing can cause permanent damage to your fingers, nose, toes, cheeks and ears. Frostbite most commonly effects areas of the body that are exposed to cold weather for long periods of time.  There are varying degrees of frostbite, from numbness and red skin to waxy gray skin.  If you notice numbness on your feet or fingers, it’s time to get inside and warm up.  The best way to prevent numbness in your extremities, is to wear layers to protect your body from the harsh winter weather. Frostbite can be very seriousness and, in some cases, amputation is the only treatment! Layering will keep you warm and protect you from Jack Frost!

Layering Protects You from Getting Wet

As I mentioned earlier, the key to staying warm is staying dry. Layering protect you from getting wet, by moving moisture away from your body and keeping rain and snow from penetrating your skin.  Why is moisture so dangerous when it’s cold outside? This is a great question.  According to medical experts, water takes away heat 25 faster than air.  WOW! That’s really fast.  So, if your clothes get wet from water or sweat, you’re losing body heat at a rapid pace.

If you fall into icy cold water, you will suffer the effects of hypothermia even sooner.  Layers work hard to prevent you from getting wet at all costs.  This is why choosing the right fabrics will keep you dry the entire time you’re outside enjoying the great outdoors.  There are some clothing lines, like Fortress Clothing that makes clothing designed to be waterproof even if you are fully submerged in an icy lake.  For more information Fortress Clothing, check out my review of the company and its gear here!

Layering works wonders to keep moisture from hanging around too long. When you have all three layers working in unison, you are setting your self up for a successful and warm adventure into the winter wilderness.

The basics of layering are the same for everyone, across the board.  However, your layers may change based on your activity.  A heavy middle layer down coat may not be appropriate for summiting Mt. Rainier. You may find a heavy down coat with an 800 fill, is too warm for your level of activity.  You may save that coat for when you’re camping in late October and you’re sitting around a campfire.  When choosing your layers, always think about what you’ll be doing. You don’t want to risk getting too hot. If you’re layers are not appropriate for your level of activity, you may overheat and find yourself stripping off that middle layer, mid-way through your winter excursion.

As soon as you take off that outer layer and middle layer, you’ll cool off for a moment and then you’ll start to lose all that precious body heat your base layer was designed for.  Then you start to get chilled and you can’t seem to warm up.  If you get overheated, you’re at risk of reducing your body temperature as well.  If you’re spending a lot of time outside for various activities, you may consider buying multiple weights and styles of middle and outer layers.  That way you can mix and match your layers depending on the weather and what you’re doing.  You may just need a base layer, fleece vest and water-resistant outer layer for day hike in late April.  However, that same hike in October may require a down jacket as your middle layer to add extra warmth.

Layering plays an important role in keeping your body temperature at the perfect 98.6 degrees! Layering is essentially a thermostat for your body. Choosing the right fabric and wearing all three layers will keep you warm in the winter and keep you alive!

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