For outdoor activities that last hours to days, like hiking and backpacking, you need to understand what base layer clothing is, and how to use it. Doing so could mean the difference between having a warm, dry, enjoyable, and possibly less stinky outdoor experience, versus a cold, wet, miserable time, with a higher risk of hypothermia.
What is base layer clothing?
Base layer clothing, for hiking or otherwise, is the very first layer of clothing that goes up against your skin, and which is part of a larger layering system used to regulate your body temperature when outdoors. The purpose of the base layer is to wick sweat away from your body to minimize heat loss related to its evaporation directly from your skin. It also allows that sweat to evaporate faster than it normally would, were you to wear a non-base layer garment against your skin, i.e. one made with cotton fibers, or which is loose fitting by design.
Base layer clothing should be form fitting
Base layer clothing can be shirts, pants/leggins, underwear, and even moisture wicking liner socks. But whichever part of the body it’s covering, the idea is that it should be relatively tight and form fitting, so that it’s touching as much of the skin as possible, to keep sweat off your skin, on any part of your body.
It should not be used as insulation
Often manufactures offer lightweight, mid-weight, and heavyweight base layer clothing. But generally the lighter your base layer clothing is, the more efficient it is at pulling sweat off your body and evaporating it to keep you dry.
Further, you shouldn’t be using your base layer as an insulating layer. Only your insulating layer should be used for this purpose. If you need more insulation for a particular excursion, then get an insulating layer that has more insulation!
Thus it’s best to stick with the lightweight and mid-weight options, when picking a base layer. This is especially true for hiking or other activities where you are going to generate a lot of sweat.
Understanding the different materials used for base layer clothing
The materials used to make base layer clothing are either synthetic, wool-based, or a blend of these. You can not use cotton or a cotton blend garment as a base layer, because cotton just holds onto moisture and takes forever to dry out. Let’s take a look at the main material categories and their particular uses with regard to hiking.
Merino Wool
Merino wool is light, soft, and can be worn for several hours or days without it getting too stinky. Unlike regular wool it is not itchy and actually feels good against your skin. Further it can hold a significant amount of sweat relative to its weight before you feel like you are wet from sweating.
Because merino wool that has had sweat on it for hours or days doesn’t stink, it may be a good choice for multi-day backpacking and camping. Your sleeping bag, if not using a liner, will thank you and be less pungent when you make your way back to civilization. And if you’re sleeping next to a partner in a small tent, they too will thank you for wearing this material as your base layer.
However, merino wool is not as strong as synthetic materials, and may not hold up to abrasive maneuvers, like carrying a heavy pack. So if you anticipate shedding your shell and insulating layers during your hiking/backpacking trip, this might not be the best option for you. But if you have your heart set on not being stinky in the backcountry, at least choose a mid-weight option to hold up a little better.
Same goes for washing thin merino wool. It may develop holes after you wash it several times.
Another disadvantage to merino wool is that it is not as quick drying as synthetic material. This may be of importance to you if you are a heavy sweater, or are performing a strenuous hike, or other activity. Heck, if you’re not an ultra-lighter, you may want to just bring a merino wool base layer for hanging out around the camp and sleeping. Then pack a synthetic base layer for hard hiking and sweating.
Synthetic material
Common synthetic materials for base layer clothing include polyester, acrylic, and cheaper pieces may have spandex or rayon.
Synthetic base layers are more efficient at wicking and drying than wool based ones. They also are stronger and more able to deal with the abrasive forces of a heavy backpack. These are thus good for more intense activities.
But the synthetic base layer materials also tend to stink worse after getting sweat in them. They also can feel a little colder against the skin, even when not wet.
Related: Check out my review of the Flylow Garrett summer base layer shirt for hiking, mountain biking, and casual hot climate wear. This one is an ultra lightweight synthetic base layer.
Synthetic plus wool blend base layer clothing
One tip on feeling less moist or cold with a synthetic base layer is to find a product that is a blend of both synthetic and merino wool. You may feel warmer while still getting the excellent wicking and drying of the synthetic fibers. And these days even a 90% wool/10% synthetic base layer material is still cheaper than the 100% Smartwool option.
Silk base layers
Silk base layers are the warmest of the three main material categories. They are also the softest against your skin. However like merino wool base layers they’re not as efficient at wicking sweating. Nor do they hold up to abrasive forces.
If you know you’re just going to use them around camp or in low sweat activities, silk based base layer clothes may be a warm choice for you.
Summary and further reading
Thanks for checking out my article on base layer hiking clothing!
I hope it gave you some quick insights into using base layers on your next hiking, backpacking or other outdoor excursion.
Next, check out my hiking and camping clothes page, or winter hiking and camping page for further reading related to hiking base layers.
See ya out there….