Base layers

Base layers

Base layers are important as they keep you warm and dry.

Base layers 

Base Layers

One of the things you’re trying to do for a successful day in the hills is to stay dry.  So maybe you’re wondering what base layers have to do with staying dry. Should we instead be talking about waterproofs? Of course, a waterproof is important to keep you dry from the outside, but good base layers will help to keep you dry from the inside out. 


When we engage in physical exercise our bodies tend to heat up, and a means for the body to regulate its temperature is to sweat, which causes cooling.  Sweating is fine, but under a waterproof shell it had a tendency to stick around, cause condensation and make our clothes wet.  A good base layer will draw moisture away from the body where it can evaporate, by a process referred to as wicking. Some fabrics are better at this than others.


Cotton is poor at drawing sweat away from the body. Thus, wearing a cotton T shirt for a day in the hills is probably one of the worst things you can do, as it will hold on to sweat.

Having a sweaty T shirt in itself is not the issue.  Apart from being uncomfortable, the moisture will cool down when you stop pumping out heat, i.e. when you stop walking for any period of time. It is then that the moisture becomes a problem, as it will cool down and cool you down in the process. Water will cool down the body about 25 times quicker than air, by a process known as conduction. If you’ve been out in the hills, worked up a sweat then stopped for lunch,you’re probably aware of all of the above and have experienced first hand the effect of cooling in this way. 

Put yourself in a situation where you’ve just walked a few miles up a hill, and now there’s an emergency situation and you have to stay in the same location for a few hours. If you have a non-cotton base layer you’ll be drier than if wearing a cotton T shirt. You will cool down less quickly, meaning that you will be less susceptible to the onset of

Equipment manufacturers have an array of fabrics that have actual or perceived advantages over competitors products, but at the end of the day most of the outdoor base layers wick away sweat better than cotton. Make sure you wear a wicking base layer.


On a footnote; base layers include underwear, so make sure that you wear non-cotton undies & socks.

1,000 mile socks are a great liner sock that wick sweat away from your feet.


Despite wicking sweat away from your skin and drying much better than cotton, even the best base layers will become damp with sweat sometimes. Consider taking a spare base layer T shirt, which would be invaluable if you have to stay put for a considerable period of time; having a dry T shirt next to your skin will prevent heat by conduction.

The Layering System Explained

Click here for more information on the layering system, together with a couple of videos.