If you plan to spend time outdoors, especially in colder months, choosing the right base layer is crucial for maintaining a comfortable body temperature.
A ‘base layer’ refers to the layer of clothing closest to the skin. Ideally, a base layer should be close-fitting and be made from a moisture wicking material.
How do base layers keep you warm?
A base layer is designed to trap a thin layer of air between the skin and the material, which is then warmed by body heat (in a similar way that a wetsuit works by trapping a layer of water against the skin).
Quality base layers also have moisture wicking agents within the material which draws sweat away from the body. This allows any moisture to evaporate from the outer surface of the material or be transferred through the next layer until it gets to the outer garments from where it can evaporate, keeping the wearer dry and comfortable during active periods.
What are base layers made of?
The majority of base layers are made from a synthetic material (such as polyester or a polyester/elastane mix) or from natural Merino wool.
Why are base layers better than t-shirts?
The majority of t-shirts are made from cotton or a cotton mix. While this may feel warm/comfortable to begin with, as soon as activity starts, the material will soak up and hold any moisture – making the t-shirt damp and heavy. You then end up with moisture being held against your skin which then draws heat from your body which defeats the whole purpose of wearing a base layer. Plus t-shirts are not designed to fit as snugly as base layers, which makes it more difficult for the area between your skin and the material to become warm as a result of body heat.
To find out more about the theory behind layering, visit our layering guide.