Updated: Mar 28, 2020
What do you do when you are cold? Most would put on another layer, a jumper or a fleece.
What if it is really warm? Do you wear less clothing which is lightweight to help us stay
We already have a good idea about layering clothing to suit our needs and environment but there is a little more to it than we first think.
What is the Layer system?
The layer system is the method of which we put on clothing for outdoor Adventures.
Each layer has a job to play and works in combination with the other layers to provide effective protection from the environment your in.
If the layer system is working efficiently it will have an impact on the energy you use to either keep yourself warm or to cool yourself down.
It’s a much better way to dress for outdoor activities, rather than putting on one large jumper and overheating when you are active it allows us to regulate our bodies temperature through the ability to add or remove layers, adapting to the energy we are putting in to the activity and what the weather and environment is throwing at us.
The types of clothing and which layers we wear depend on the activity we are participating in.
For example, a climber may want thinner, more light weight layers to help him or her regulate their temperature but also allow them the freedom to move and position themselves while climbing.
A hill walker, on the other hand, may want several good layers to keep them warm but without sweating to much and also staying dry from rain.
For this blog post we are going to focus on the fundamentals of the layer system and the roles each layer does. It is then up to you to experiment and play with these to find what works best for you. There are no wrong or right answers here, just the feedback you get when you are out on your Adventure.
The layer system is made up of 3 layers and accessories. These layers are,
Base-Layer, Mid-Layer, Outer-Layer and Accessories.
Why is the layer system important?
We can face some tough conditions on our Adventures and it’s important make sure we are able to look after ourselves and the people we may be with.
If we are worrying about our condition or if we are becoming uncomfortable because our clothing isn’t working we lose focus on enjoying the Adventure we are having and it can quickly become a misadventure.
Having the ability to regulate our body’s temperature and adapt to the prevailing conditions allows us to prevent the situations that can lead to life threatening conditions.
Overheating, either through our own physical exertion or from the environment we are in, causes us to sweat.
Our sweat makes our clothes damp.
This moisture, coupled with warm air escaping from your body, being replaced by cold air, say through a breeze or the wind can cause your body temperature to drop.
In cold or wet and windy weather this can lead to serious issues and cause you to become a casualty.
If your wearing to much, or wearing to little and exposed to the sun and heat for too long in hot environments, then again, you can overheat and become a casualty very quickly.
Understanding how to use the layering system and the types of clothes in each layer helps to prevent any issues so we can enjoy the Adventure we are on!
How does the layer system work?
Each layer has its own job to do. The big picture is to create and trap a layer of warm air against your body to act as insulation but also to remove (or wick) any moisture away from our bodies so it can evaporate quickly and easily. It also is designed to protect us from the outside coming in, for example from the rain and the wind.
So we can really get our heads around the role of each layer, it is first really useful to understand how our bodies warm themselves and how we lose heat. This can be a fairly interesting and in-depth subject so in the interest of keeping things brief, our bodies warm themselves by burning calories from our food and so we need the calorie intake to keep ourselves warm.
Now consider that you may need more calories to keep your energy levels up while participating in an outdoor activity and you quickly see that you need a few more calories while outdoors then when you are at home.
Our bodies cool through 4 methods, these methods are,
Convection, Conduction, Radiation and Evaporation.
Convection is what happens when we stand in front of a fan on a hot day.
Our body heats the air that it is in contact with, that air is then replaced with cooler air which is then heated again and replaced again and so on…
The cooler air takes away the warm air around our bodies and so we begin to feel the effects of the cooler air, this is why it is really nice to stand in front of a fan in the summer, but its not much fun in the winter.
In order to prevent the warm air being lost we need to do 2 things.
1. Trap the hot air so it doesn’t escape, ideally keeping it next to our skin, and
2. Protect against the cooler air from taking the warm air away.
This cooling effect is intensified with the addition of moisture and this is why our bodies create sweat. This leads us to the next cooling method that is…
Evaporation occurs when we sweat which then dries.
Our bodies create sweat for a number of reasons, the reason we are focused on here though is from physical exercise through an Adventurous activity, although there may also be some times that push our limits and we sweat due to being excited or a scared too.
The water in our sweat heats up and turns in to water vapour, which removes the heat from our skin cooling us down.
This is perfect in warmer environments as we want to regulate our body’s temperature to stay cool but we need to be careful about how much we sweat as it can lead to dehydration, cramps and other serious conditions.
In colder environment we want to reduce the amount we sweat to reduce the cooling process and keep ourselves warm.
Layers in the layer system carry the sweat away from our skin so it can evaporate, we call this wicking and this is why we look for clothing that is ‘breathable’ as it allows the sweat to be wicked away but it still protects us from things like the sun or the cooler air if we are in colder environments.
Conduction happens when we touch something that is colder than ourselves.
A classic example is when we touch a metal pole in the winter, with no gloves on. Our body transfers heat to warm the colder object to match our own body temperature.
We lose heat this way in a number of ways and depending on the activity we are taking part in depends on what we are losing our heat too.
For example, a hill walker will be walking across cold ground, they may be carrying walking poles and may sit or lay on the ground to rest, a climber will be touching rock with their hands and a paddler will be sat or knelt in a boat.
To reduce or prevent the heat being lost through conduction we need to create a barrier to insulate ourselves from the object we are touching.
This method is transference of heat with the environment that we are not directly in contact with like convection or conduction. It is the this method that allows the sun to warm the earth.
As human we naturally give off heat in to our environment, for example it is thought that we lose a huge amount of heat through our head that radiates heat out in to the environment around us.
When I was in school we were told we lose between 40% and 45% of our body temperature through our head and it was very important to wear a hat in cold weather.
This has actually been found to be not entirely true and while we do lose a significant percentage of body heat through our head it is other areas of our bodies that we should be aware of such as our legs, bum and our torso.
To reduce this heat loss we use our clothes to trap the heat and to minimise the amount of heat we give off.
What are the layers in the Layer system?
Now we know the ways we lose heat and how we create heat lets take a look at the layers we can use to reduce and prevent heat loss and wick moisture away from our skin.
This layer is the first one we put on, after our underwear, and is worn next to our skin.
Its job is to trap a thin layer of warm air next to your skin but it also wicks sweat away from your skin when you are working hard.
Good items of clothing for this layer are things such as long or short sleeve breathable t-shirts, leggings or tights, sports tops or purpose made base layer clothing.
Avoid any cotton t-shirts or leggings as cotton holds moisture and keeps you cold. It also takes a longer time to dry compared to other fabrics and therefore needs more energy to dry it.
Ideal fabrics for this layer are Merino wool or bamboo which is becoming more and more popular, natural fibres are better as they hold the heat longer when you stop moving.
At a glance:
· First layer you put on and is worn next to the skin.
· Traps warm air next to the skin.
· Wicks moisture from sweat away from the skin.
· T-shirts, leggings or purpose made base layers are good.
· Natural fibres are good, avoid cotton.
This layer is worn over the base-layer and is sometimes referred to as ‘the working layer’ as it is made up of items of clothing that you can do the activity in if your not wearing your outer layer.
Its job is to provide protection form the outside elements while you are participating in the activity but it also carries on the job of the base-layer, trapping warm air in, creating insulation while allowing moisture from sweat to escape.
Good items for this layer are thin fleeces, Merino or other walking type jumpers or hoodies, thin windproof coats and walking or climbing style trousers.
There are many variations in fabric and cut to choose from including thin light weight trousers and tops ideal for summer hillwalking, mountaineering, climbing or fast paced activities requiring a lot of movement and freedom.
There are also thicker fabrics commonly known as ‘soft shell’, which give better protection from the wind and can sometimes be shower or splash proof. These are great for cooler conditions or higher altitudes.
If your walking in cooler, windier, wetter conditions the heavier soft shell and warmer type tops may be better to protect you from the wind and the damper conditions. However, if your walking in the summer months then quick drying lightweight clothing that can protect you from the sun and summer rain may be better.
Some items of clothing have vent zips built in and are specifically designed for the job of being worn as a mid layer.
At a glance:
· Worn over the base layer.
· Traps warm air to act as insulation and continues to remove moisture from sweat away from the body.
· Lightweight fabrics or soft shell fabrics are great but depend on the environment you are in.
· Provides protection from the environment while doing the activity and is worn as a day-to-day clothing.
This is a layer that is can be either carried in a rucksack or worn from the start. Because it is often in your rucksack it is great to have lightweight clothing make up this layer and many brands are making lighter and lighter garments which still stand up to very challenging conditions.
There are a couple of jobs this layer can do. It can provide further insulation, it can protect from the wind and from the rain.
This layer is made up of clothing which is often referred to as ‘hard shell’ clothing and it is this layer which often sparks the debate between those who prefer Gore-Tex and those who prefer Parmo clothing.
Breathability is an issue with this layer, as this layer still needs to be able to allow moisture from sweat out as well as prevent moisture from things such as rain in.
Many waterproof jackets have vent zips built in to key areas such as under the armpits to allow for fresh air to circulate removing the moisture.
Whichever type of outer layer you choose the items need to be able to protect you from the wind and the rain.
The items of clothing are things such as a waterproof jacket and waterproof trousers.
It is also advisable to wear these items even if it is not wet as they can protect you and keep you warm if it is windy. Legs are big muscles and we lose a huge amount of body heat through them, people often overlook the protection of the legs against the wind and the rain so a good pair of waterproof trousers can make the difference from being warm and happy to cold and 'wanting to call it a day'.
This layer can also provide another layer of insulation and many people carry a larger warm jacket or coat to put on over everything when they stop for breaks. These jackets or coats can be made from synthetic filling or from natural down filling.
Again, there are big debates around these fillings and something I will cover in another blog post. For now though, synthetic is great in wetter environments such as UK winters and down is better where it is drier.
At a glance:
· Worn over other layers but can also spend a lot of time in your rucksack when not needed so consider it being lightweight but still up to task.
· Provides protection from the wind and the rain and can add more insulation.
· Must be ‘breathable’ to allow moisture to escape.
· Gore-Tex and Parmo are great for this layer.
· Synthetic or natural down provide another layer of insulation.
When you are preparing to go on your Adventure consider the phrase
This simply means wear layers that you need but remember once you get going on your chosen activity you could warm up and become uncomfortable very quickly. Starting cold and wearing the layers to keep you protected but able to stay cool once your well in to your activity will help to reduce any build up of heat or sweat.
Have a vent stop.
It is often a good idea to stop sometime between 15 – 30 minuets in to your first hour of activity to remove any additional layers you may have on. Sometimes the weather can change for the better or the terrain may be tougher than we considered or we just need to take a layer off if needed.
Have a vent stop and alter your layers as needed.
Hats, gloves, socks and wristlets are all very personal choices and have a huge range to choose from depending on the conditions you are likely to face, the type of activity you are taking part in and what works for you.
What ever you do always consider carrying a spare hat and a spare pair of gloves. Having a dry hat and gloves can sometimes make a huge difference to your moral and your condition when out on an Adventure.
There is a wide range of hats available. The classic beanie or bobble hat is always popular in the outdoors and many brands make great beanies or bobble hats. Many are made with a wool mix and can keep your head warm even when they are wet.
The alternative for cold wet weather is the mountain cap. These are made from a Gore-Tex outer and are fleece lined. These are fantastic in the wet and I spent a lot of time wearing mine in Norway and the UK in the winter.
For summer months a good baseball cap is useful to have but the sun can often catch people out and burn the back of the neck. Consider having something like a buff or a baseball cap with a neck shield to prevent this. Alternatively a good wide brimmed hat may make you look a little bit like an explorer but helps to keep you cool and the sun off your face and neck.
Gloves are items of clothing that need to be tried out. My own experience is that there is no one glove to suit all your needs and so personally I now carry several pairs for different jobs depending on where I am going and what I am doing.
Consider the ways we lose heat, what you will need them for and where you are going when choosing gloves, having a couple of pairs with you is also a good idea.
Contact gloves, are thin gloves that are useful if you need dexterity to do fiddly tasks for short amounts of time. These create a barrier between you and the things you are touching and reduce the amount of heat conducted away from your fingers and hands.
Insulated gloves are bigger gloves with good insulation, like a ski or mountaineering glove. These will keep your hands warm and are worn for most of the day. Your hands will sweat in these gloves so it is best if they are breathable and some people like to wear a liner glove.
Liner gloves are very thin gloves make from either cotton or silk that act in the same way a base layer does. It wicks the sweat away from your skin and allows the insulated glove to wick it further so your hands remain dry. Carrying a spare pair of gloves to put on if your hands get to wet is a good idea as once wet gloves are not as effective as dry ones.
Mitts are a very good option if you do not need the use of all your fingers. Mittens are made so that all your fingers share the same pocket, that way your fingers share warmth with each other. Mitts are more efficient at keeping your fingers warm rather than relying on the insulation in gloves with a pocket for each finger however you lose the ability to use your fingers if you need them for certain tasks. Having a set of mitts to put on if your hands are very cold is also a good idea as it can help them to re-warm when needed.
These are items of clothing that are commonly overlooked and not easily found within many outdoor stores.
I was issued a pair of wristlets for each deployment of Norway and they certainly made a difference in the cold environment.
They are designed to wear around the wrist and the back of the hand and add a layer of insulation around the wrist where the blood vessels are close to the skin. It is an area that can be problematic as the glove stops and the cuffs of other clothing may not provide a huge amount of insulation to this area.
A pair of wristlets can go along way to keeping your hands warm and are worth the money if you ever find any.
Alternatively many mid layer items of clothing and some base layers too, now provide longer arms with thumb loops in them to do this very job.
Socks are not really accessories and some could argue they fit in either the base-layer or even mid-layer clothing sections. However, for this article we will put them in as accessories.
Socks are a huge topic in itself and are something I will cover in another blog post.
However, consider the activity you are taking part in, what footwear you will be wearing and how far you will be walking as well as the terrain you could be crossing.
Socks come in a variety of weights, fabrics, manufacturing methods and lengths and are something you need to again spend time on trying out and getting feedback from.
Socks can make a huge difference between hot sweaty feet that are prone to blisters or dry warm feet that are blister free.
Good walking socks are worth the money so don’t skimp on these items of clothing.
What about staying cool?
It may appear that the layer system is focused mainly on keeping us warm in the colder weather and environments. However, it is also important to consider how you dress in the hotter environments.
I have spent time in the hills and mountains all over the world and witnessed people wearing only shorts and t-shirts in very hot and sunny conditions.
Many suffered from sunburn, as they had not covered up. They then suffered from a range of issues later as the sunburn took its toll.
From my experience it is better to wear a good base layer top and lightweight trousers without base layers under them and move more slowly and deliberately.
This way you reduce your physical exertion reducing the amount you sweat while remaining covered up and protected from the suns rays.
You can also vent your clothing by opening vent zips or undoing buttons to allow air to circulate around your body to remove any build up of hot air away from your skin.
Consider applying the SunSmart campaign and
‘slip on a shirt, slop on the sun cream and slap on a hat’.
We all love to get a tan but when in the hills and mountains or on the water having an Adventure we are already looking good!
Once you stop, even in hotter environments, you may become cold quickly. Sweat will evaporate, and a breeze will conduct the warm air away from your body so it is advisable to always carry the extra layers with you so you can adapt, as you need.
The choice of clothing and fabrics is massive and it takes time to experiment, learn and develop the best combinations and garments before you find the right ones for you.
The best advice is to do a little reading around, understand what your activity will ask of you and chose the most appropriate you can find for the activity and the conditions you may face.
We are not limited to just the 3 layers, you can also add extra layers between them as you need too.
The layer system is the method of which we put clothes on for outdoor activities and Adventures. It allows our clothing to work effectively and efficiently and is made up of 3 layers and accessories.
The base-layer in the first layer we put on, its job is to trap hot air and wick sweat away from our skin.
The mid-layer is the next layer. It goes on over the base layer and is made up of clothing, which you wear to participate in the activity. Its job is to provide protection for the activity but it also insulates your body as well as continuing to wick moisture away from the skin.
The outer-layer is the final layer and its job to provide protection from the wind and rain and add more insulation as and when you need it. Hard shell clothing such as Gore-Tex jackets are in this layer as well as synthetic or down clothing to provide extra warmth as and when you need it.
Accessories such as hats, gloves, wristlets and socks have a huge variety to experiment with and differ depending on the activity you are taking part in, where you are going and the conditions you will possibly face.
If you have any questions or feedback about this post or if you would like to discuss any questions about the layer system then we are always happy to help. Please contact us and we will do our very best to help you.