If you want to stay warm this winter, you won’t go very far without a base layer. It is the layer of clothing that you wear closest to your skin. Its purpose is to trap warm air against your body and remove moisture away from your skin. Use this guide to help you decipher the best option for your chosen activity.
Polypropylene is a completely hydrophobic material. That means that the fibers that polypro is made out of will not absorb any moisture from your skin, and will transfer that moisture directly to the next layer. Polypro is great for high physical-intensity activities during the winter time because it will ensure that you are dry, no matter how quickly or intensively you sweat. While polypro is super light, it does come with its cons. It is not UV resistant so persistent wear in the sunlight will break down the garment. It also retains body odor rather easily and may not be the best option for multi-day trips. Finally, it has a very low melting point so make sure to keep your distance from any bonfires and hot water!
Example: Helly Hansen Dry Base Layer
These types of baselayers rely on wicking in order to remove moisture from the skin. How wicking works is that the garment absorbs the moisture from your skin, then disperses the moisture throughout the garment to increase the surface area that the moisture retains on the garment. The larger the surface area the moisture takes up, the faster it will evaporate onto the next layer. While polyester will work slower than polypro at moisture control, it is slightly more durable than polypro so caring for polyester is much easier.
Example: Helly Hansen Active Flow Base Layer
Merino wool is one of nature’s best defenses against the cold. Merino wool uses wicking for moisture control, but where merino wool stands out is its ability to retain moisture while still remaining dry. It can absorb up to 30% of its weight before getting wet. Coupled with its wicking abilities, it ensures that you will stay dry, even through intensive activity. Another neat thing about merino wool is that it is naturally anti-microbial. This means that bacteria has a harder time growing on wool, making your garment odor-free for longer periods of time than synthetics. This means that you can bring just one wool base layer to a multi-day trip and not smell like a skunk bomb by the end of it! Merino wool is super soft, light, and warm, and in my personal opinion, the best option for a base layer that will keep you dry and warm. Going natural is also eco-friendly, and if you buy from a reputable source like Icebreaker, you can be sure that no animals are harmed in the making!
Example: Icebreaker Oasis 200 Base Layer
Merino Wool Blends:
While 100% Merino wool can be quite costly, an alternative option for Merino wool is a merino wool blend base layer. Merino wool blends use the wicking power of synthetics in conjunction with a layer of merino wool to create a cheaper alternative, with similar benefits.
Example: Helly Hansen Warm Base Layer
I hope this gives you an idea of what to look for in a base layer, and which one is best suited for you and your desired use.
Note: I am not sponsored by these brands. I just vouch for their awesomeness!
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