Fabric content, weights, technologies - everything you need to know about base layers.
By Mat Brost
Layering clothing has evolved into the premier method of staying warm on winter’s coldest days. An effective layering system essentially consists of three layers that work together to insulate, manage moisture and protect from the elements - an outer layer for protection, a middle layer for warmth, and at the core, a good base layer for warmth and comfort.
Depending on your activity, various styles of base layers are available. Some are built solely for wear as a layer, while others are tailored for wear alone after shedding outer layers when temperatures rise. Smooth outer fibers on your base layer allow middle layers to slip on and off easily, while textured outer fibers may have better heat-retaining qualities. Available tops include short- and long-sleeve styles, crew, mock, hooded and zippered options. There are base layers available in women’s-specific styles designed to fit the female form. Some base layers are designed for everyday use, while others are specifically for hunting and high-movement activities. Advancements have also made in underwear, making performance boxer briefs a popular option for keeping your core temperature up.
The fabric content of a base layer generally comes down to personal preference and which fabrics have the inherent properties most suitable for your specific outdoor activity. The most common base layer fabrics are:
Wool Base Layer
It's flexible and highly durable. Plus, it's an excellent traditional insulator. Wool repels small amounts of liquid on the surface and wicks moisture away from the skin, but becomes easily saturated and doesn't dissipate moisture as well as synthetics. Wool also naturally resists odor and is flame retardant. Most wool garments are susceptible to shrinkage and may require special care, but technological advancements have made machine-washable wool possible.
Silk Base Layer
Known for its soft, smooth feel, silk is also strong and moderately abrasion-resistant. It's highly absorbent, so it's not ideal for intense aerobic activities, unless treated to enhance its moisture-wicking ability. The evolution of machine-washable silk has made it a popular base-layer option. Machine- and hand-washable silks are common as well.
Polyester/Synthetic Base Layer
Dries quickly, resists stretching and shrinking, and considered especially durable, lightweight and easy to care for. Made of synthetic fibers, polyester has a reputation for feeling less natural against the skin, but is generally abrasion-resistant. Its superior breathability, moisture-wicking and warmth-retaining properties make up for what it may lack in softness, and it's by far the easiest fabric to care for.
When it comes to selecting a fabric weight, it helps to keep both outdoor temperatures and your activity level in mind to maintain consistent warmth.
Lightweight Base Layer
Lightweight base layers are ideal for high activity levels in cold weather or low activity levels in cool weather.
Midweight Base Layer
Medium-weight base layers are versatile, offering optimal performance for a variety of cold-weather activity levels.
Heavyweight Base Layer
Providing intense insulation, heavyweight base layers are ideal for low activity levels in cold weather. Polar Weight is the warmest base layer for extreme-cold conditions and is fleeced on both sides for maximum heat retention. Heavyweight and Polar Weight base layers generally are not ideal for high-movement activities because they can be restrictive and become too hot.
Enhanced Base Layer Technologies
Depending on your cold-weather activities, additional technology and treatments can lead to enhanced comfort and enjoyment.
Wicks perspiration away from your skin and dries quickly. Wicking fibers transport perspiration away from the skin to the outer layer where it evaporates quickly.
Versatile for numerous weather conditions and temperatures. Three weights of fabric are strategically placed to provide superior thermal regulation where it is needed most.
Ideal for high-movement activities. Stretches in all directions for enhanced freedom of motion. Scent Control - Designed for hunting. Retains your body's scent. Antimicrobial - Prevents the growth of bacteria and keeps the garment fresher when in use and between washings.