Base layers are under garments- the tops and bottoms that directly contact your skin. Snowboarding base layers are made from all different types of polyester, nylon and wool blends but no respectable base layer is made out of cotton. Cotton holds moisture and does not dry out quickly, nor does it insulate. Moisture left on your skin transfers heat from your body making it a very dangerous fabric to wear in the mountains. And here is why – hypothermia.
When heading out into the mountains, especially the backcountry where shelter is not readily available, it is important to stay dry. To do that, your body needs to be able to regulate and manage how much heat it generates. Over heating will cause you to sweat and the dampness on your skin will draw more heat out of your body than it can replace. When this happens you run the risk of experiencing hypothermia. Hypothermia is your body’s survival response to internal heat loss. When your core body temperature drops below 95 degrees Fahrenheit, blood from your extremities (fingers, toes, feet, hands) is drawn towards your vital organs to keep them functioning. Your body will also begin to shiver and shake in an effort to generate heat. In severe cases, blood is drawn from the brain towards the heart and lungs. At this point one can experience paralysis and dementia which will leave the individual completely incapacitated and at the mercy of the elements.
So how can base layers help you from unnecessarily risking hypothermia?
Wool Base Layers
Staying dry means staying warm, and in my experience the best base layers are made with merino wool. More than any other product on the market, merino wool is comfortable against your skin, keeps you warmer and drier, insulates even when wet, and prevents you from over heating. It accomplishes this the same way synthetic fabrics do but with more efficiency. Wool fibers contain lanolin, which makes them hydrophobic allowing them to act as conduits between the warm, moist environment on your skin and the drier, cooler environment on the outside of the fabric. Since warm air is denser than cold air it naturally seeks to fill the void, so it carries water molecules (in the form of vapor) with it off your skin and to the outside, where it quickly evaporates. Also, a very unique occurrence happens with wool as this process takes place. The drawing of moisture off the skin as it evaporates cools the body, as it normally would, but also, the energy transfer of vapor being moved through the wool creates heat that gets trapped in the wool fibers’ unique cuticle patterns. This means you stay dry and insulated at the same time.
Wool base layers are also form fitting and stretchy so you can comfortably layer over them. They do not stink and can be worn for multiple days. If you do need to wash them, a quick rinse with mild (non-chemical, non-fragrance) soap and water will do the trick. Plus, they dry really fast- hang them up to dry at night and they are ready to be worn by the morning making them great to travel with.
Synthetics Base Layers
There are many synthetic fabrics that also wick moisture off your skin efficiently. Many companies make proprietary blends that are trademarked and are designed to do much the same thing as wool. These fabrics are usually a blend of polyester, nylon and sometimes spandex. Polyester aids in wicking moisture and keeping you dry. Nylon adds strength and durability to the fabric and spandex keeps the garment form fitting. Form fitting clothes are important because the fabric needs to be close to your skin in order to wick moisture away efficiently. The fabric cannot properly do its job if there is too much space between your skin and the fabric. Synthetics also dry out very fast making them ideal for warm weather pursuits where one may be undergoing an excessive amount of sweating.
Other benefits of synthetics are that they are usually very light and easy to wash. Unlike wool though, they will stink after a couple of uses before being washed. Though some synthetics are treated with anti-microbial chemicals that help them combat the stink issue. Synthetics are also easy to maintain and many can be thrown in the drier. Wool and dryers do not get along unless the garment has good amount of synthetic material woven into it. Both merino wool and synthetics are comfortable to wear and they resist stains and wrinkling. Both dry out fast but wool insulates and keeps you warm even when soaking wet. On the other hand, wool is more expensive to harvest and manufacture than synthetic fabrics which are petroleum-based. Therefore the price of wool products tends to be higher.
Whether you go with wool, synthetic or a wool/synthetic blend, keep in mind that you want your snowboarding base layers to fit close to your skin and still give you enough room to move about freely. If you are doing cold weather activities give wool a try. For warm weather sports try synthetic products. Keep in mind that both work well for many outdoors applications, and high quality base layer clothing is designed to be your first line of protection against the elements.