Base layers are the foundation of layered outdoor clothing systems. If you are going to be active outdoors you need clothing that is warm, tough, dry and adaptable. The best way to dress for the changing weather and the varied levels of activity, is to use a layered system of clothing. Layers can be removed when temperatures or activity levels increase, and when the temperature plummets or a storm blows in, layers can be added to adapt to those conditions.This simple system uses a base layer next to your skin, a mid layer or insulating layer over top and finally an outer shell layer. The function of the base layer is to keep you dry, the mid layer keeps you warm, and the shell layer protects you from wind, rain and snow.
“These new fabrics are not your
father’s long johns!”
When we talk about base layers, what we are really talking about is long underwear. Let’s call it what it is, but these new fabrics are not your father’s long johns! Thermal underwear of the past was either a low performance cotton/synthetic blend, or a warm but scratchy wool outfit.The new high tech fabrics that have been developed excel in moisture control and comfort.
Although this is long underwear, once you own a set of these you will find they are suitable as wear alone garments in many situations. Many of the lightweight garments are great on their own for hiking, running, or other outdoor activities. I have even seen people wearing them in the gym.
Moisture Control
Moisture control is the main job of the base layer. Keeping your body dry is the number one key to being comfortable in the bush. Wet clothing will steal heat from your body extremely quickly and can lead to potentially life threatening hypothermia.
When you become active, your body temperature starts to rise and you begin to sweat. The job of the base layer is to move the moisture away from your skin. This process is called wicking. Just as a candle wick draws melted wax up to the flame, the fabric of a base layer wicks moisture from the humid area next to your skin and transports it towards the outer surface of the base layer.
Fabrics
There are three main types of fabrics that have been developed for use as base layers: synthetic fabrics, merino wool and silk. No one fabric is the best in all weather conditions, each has it’s advantages and disadvantages.
Synthetic Base Layers
There are many different synthetic fabrics that have been developed for use as moisture wicking base layers. The main component of most of these fabrics is polyester. Polyester’s big advantage is that it does not absorb water. Some manufacturers blend the polyester with nylon or spandex, and many have specially shaped fibres designed to enhance the wicking characteristics of the fabric.
Advantages:
- Comfortable, wrinkle resistant and easy to take care of.
- Proven excellence and reliability in moisture wicking.
- Generally the least expensive.
- Available in a wide variety of colors.
- Fast drying.
- Best all around choice for most activities.
- Best for wet or humid conditions.
- Light weight and small volume for back packing.
Disadvantages:
- Retains odors if worn over an extended period.
- Made from petroleum. (Some fabrics are made from recycled plastics).
- Usually solid color only although some camo patterns are made.
- Prone to staining.
Merino Wool Base Layers
Merino wool is the name given to a very fine wool fibre that is taken from the Merino sheep. It is the Cadillac of base layer fabrics, and is very comfortable and adaptable and is naturally anti-bacterial and odor resistant. Merino wool does not wick moisture in quite the same way as synthetics. While some wicking does occur, Merino wool absorbs up to one third of it’s weight in moisture, drawing it away from the skin and moving it to the surface for evaporation. Merino wool really shines in cool or cold conditions but is actually quite comfortable in moderate temperatures.
Advantages:
- Comfortable and soft next to the skin.
- Usually machine washable (Read the care instructions).
- Proven excellence and reliability in moisture management.
- Warmer than a synthetic garment of the same thickness.
- Made from natural fibres.
- Merino wool will retain some warmth even if damp.
- Best choice for cool or cold conditions.
- Naturally odor resistant.
- Merino wool contains lanolin which has antibacterial properties
- Surprisingly comfortable in moderate temperatures as well as cool conditions.
Disadvantages:
- Generally the most expensive.
- Some garments must be hand washed.
- Usually available only in darker colors.
- Slower drying than synthetics.
Silk Base Layers
Silk fabric in its natural form absorbs and retains moisture and is unsuitable for a base layer. The silk fabrics that are used for base layers have been specially treated to improve their moisture wicking properties and to decrease the amount of water they absorb. The primary benefits of silk are it’s smooth texture and light weight. If you are buying silk as a base layer, make sure it is treated for moisture management
Advantages:
- Ultimate comfort and smoothness next to the skin.
- Fair to good moisture management.
- Warmer than a synthetic garment of the same thickness.
- Made from natural fibres.
- Good choice for cool or cold conditions.
- Fair odor resistance, better than synthetics but not as good as Merino wool.
Disadvantages:
- Generally somewhat expensive.
- Some garments must be hand washed.
- Slower drying than synthetics.
- Too warm for vigorous activity or warm weather.
Fabric Weights
Base layers are typically available in four weights:
- Micro weight – for high activity levels or warmer conditions.
- Light weight – for moderate to high activity levels and cool to moderate conditions.
- Mid weight – for moderate to low activity levels and cool conditions.
- Heavy weight – for low activity levels and cold conditions.
A similar perspective on video.
Don’t Wear Cotton
Cotton can be great for keeping comfortable in warm dry climates. However, as a clothing layer for any other outdoor situation, it is unsuitable, uncomfortable and dangerous. Unlike wicking base layers, cotton actually absorbs water and holds it next to your skin. This makes you uncomfortable because you feel wet and clammy. Wet cotton also tends to chafe your skin causing more discomfort. However, he worst thing about cotton is that it has no insulation value when wet. If the air temperature drops, wet cotton will quickly pull heat out of your body leading to potentially life threatening hypothermia in cool or cold conditions.
So leave your jeans, your souvenir cotton t-shirts and other cotton garments at home when you head outdoors. Check the labels on all your garments and avoid all the cotton blends. Don’t wear fabrics labeled as denim, flannel, corduroy or duck. These are all types of cotton as well.
Personal Thoughts and Tips:
I have spent a lot of time hunting in Canada in a lot of conditions. I own both synthetic and wool base layers and use them both. I have never purchased silk base layers and probably never will.
Like most things, there are personal preference for layers. Some people sweat more then others, some people get cold easier than others and some people have a lot more money than others. For me, I find a lightweight synthetic base layer to be the most cost efficient and versatile and I use different mid layers to control the heat.
Day in, day out, I use synthetics more than wool. They are comfortable, fast drying, versatile and less expensive. The biggest problem I find with the synthetics for hunting is their odor retention. If I am hunting from home this is not a problem as they are easily laundered. If I am going on an extended hunting trip, I usually prefer to take the wool. One trick with the synthetics is to take an extra top with you (they pack really small). At the end of the day or after a period of intense activity, take off the smelly top and hang it in the open air overnight where the breeze can blow over it. The air moving over and through the garment dries it and removes a substantial amount of the odor. You will also be a lot more comfortable around camp in a clean dry top. A small bottle of hunter’s scent killer also helps on multi-day trips.
There are special fabrics designed for hunters that both act as a base layer and help control odors. Watch for an upcoming post on this topic.
Finally, don’t screw up your layering system by wearing cotton briefs or t-shirt under your base layer. I have done this once or twice by mistake and never will again. Cotton undergarments retain moisture, hold it against your skin and defeat the wicking capabilities of the base layer. You don’t want to be sitting around camp in soggy briefs! Buy some good quality synthetic briefs for your outdoor activities.
John Dewey
2012 baselayers.ca