How to properly dress in layers with the three-layer system (2024)

Breathable base layer for wicking away moisture

When we exert ourselves our body temperature increases. To prevent overheating, our body's response is to perspire. The evaporation of sweat on the surface of our skin cools our body down. When sweat comes into contact with the air, which is usually colder, the water vapor condenses and turns into water on the skin's surface.

A wet t-shirt, especially if it is made from an absorbent material like cotton, will make you feel cold as soon as you stop exercisingdue to the moisture that stays in contact with your skin.

The aim of a base layer worn next to your skin is to wick sweat away so that you stay dry.

Synthetic materials like polyester or polyamide are water-resistant: they don't absorb water. Any moisture moves towardthe outside of the clothing so it isn't in contact with your skin. Wearing a t-shirt made from a synthetic material allows your body to regulate its temperature without feeling cold. These materials also dry very quickly.

There are also base layers that are made from merino wool. Wool can absorb up to 33% of its weight in water, so why do we use it as a base layer? This really absorbent material prevents perspiration from staying in contact with your skin and even wet wool is a good insulator. Lastly, wool prevents odors from developing so you don't have to wash your merino clothes after each wear. Base layers made from merino wool are, therefore, particularly useful for low-intensity exercise.

There are also materials that are a mix of synthetic fibers and wool. They allow you to make the most of their respective qualities combined in one outfit.

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Insulating mid-layers to keep you warm

A mid-layer will protect you from the cold by conserving the heat generated by your body.

The ability of the fibers to keep the air locked in is what makes it an insulating layer. The more air it locks in, the more your clothes will maintain your body heat.

Adapt your mid-layer to your warmth requirements:

• High outside temperatures or sustained exercise: in these conditions, you can go without a mid-layer. However, remember to put a warm layer in your backpack to use if you stop and get cold or if there is a change in the weather.
• Cool weather conditions: a fleece is ideal as it combines warmth with good moisture removal qualities. Light, synthetic insulated jackets are also useful as they will keep you warm, compress down easily, and are easy to clean.
• Cold or glacial conditions: thick down jackets are excellent mid-layers in really cold conditions. This type of jacket is lightweight and can be compressed down (useful when you need to get it in your backpack). On the other hand, if duck down gets wet, it clumps together and it loses its insulating qualities. These jackets shouldn't be used in wet weather or when you are likely to sweat a lot. You also need to be careful when washing your down jacket to ensure it keeps its shape.

If you wear a mid-layer that insulates too much, you are going to be too hot and sweat a lot. When wet, your mid-layer will lose its insulating qualities and all the accumulated moisture will increase the feeling of cold.

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Waterproof or shielding outer-layer to protect you from the elements

When protecting ourselves against the elements, we immediately think of Gore-Tex jackets, yet there are other brands of waterproof and breathable membranes. If you want to compare their waterproofness, there is a water column test (Schmerber rating) that measures (in millimeters) the resistance of the fabric to water pressure. For example, Gore-Tex jackets have a rating of 28000 Schmerber.

Waterproof clothing also has waterproof seams.

Membrane breathability is measured in g/m2/24 hours or,for the Gore-Tex brand, the RET value is used (measurement of the resistance to evaporative heat loss). The more breathable the fabric, the more suited it is to high-intensity exercise.

Some jackets have zippered vents to improve perspiration removal.

For extra protection against the wind, while remaining breathable, some clothes are made from the 'Windstopper' membrane.

Water-repellent clothing, also called softshell, is very flexible and feels nice to wear. It is breathable, so sweat is removed when you exert yourself. If the weather conditions deteriorate, the water-repellent treatment on the outer shell of the material, or in some cases on all of the membrane, will be enough to protect you from light rain or a quick rain or snow shower.

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Adapt your layering to the weather conditions

The layering system encourages the removal of perspiration as well as protection from the elements. It can accommodate all eventualities. On the same day, the weather conditions, or your requirements can change (a drop-in exercise intensity, deterioration of weather conditions, change in altitude). Remember to adjust your layers taking into account all of these factors, and be prepared by making sure you take everything you'll need in your bag.

No mid-layer for trail running in hot weather

When it's hot, you will only need to remove perspiration. Just a technical base layer will be suitable. An outer-layer may be necessary to protect you from the rain, but you can go without the mid-layer as you won't need warmth.

For a hike in the mountains, think about differences in temperature.

When you hike in the mountains, you might come up against a few different scenarios:

• Early cool mornings: wear a thin mid-layer
• Exercising in hot weather: despite the high altitudes, it's often hot when you hike in the summer. Just wear a breathable base layer.
• A sudden drop in temperature: when you arrive at the summit, if you slow down or there is a chill in the air, you can get your mid-layer out of your backpack. This could be a fleece or an insulated jacket (with down or synthetic filling).
• Wind or rain while descending: wear a softshell or a waterproof jacket. Put a mid-layer on underneath your jacket if you are cold.

Manage the cold and wind when skiing

When skiing, and for the majority of winter sports, protecting yourself from the cold and wind is essential. A long sleeved base layer is recommended.

A ski jacket sometimes combines insulation and protection against the elements (mid and outer-layer). If your jacket doesn't keep you warm enough or it's very cold, you could add a fleece layer as well.

To find out more, read our article on how to dress for skiing.

Adapt your layering for ski touring

The three-layer system is particularly suited to touring and freetouring. You can pack your insulated jacket in your bag while climbing so you don't overheat, and then put it on before skiing down.

You can stow your windbreaker and waterproof jacket in your backpack during nice weather but might prefer to wear it for protection from the cold wind that can often be felt in the mountains in winter. Of course, if it snows it will also keep you dry.

The three-layer system can also be used on the lower half of your body, but generally your legs don't perspire as much, so the principle is simpler. Ski pants combine insulation and protection and can, therefore, be worn next to your skin or with a thermal layer underneath. On a summer hike, shorts or light pants are often enough. You can add rain pants over the top if it rains or if it's windy.

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