Our body is a self-regulating system which ensures that we constantly stay at the right temperature. It works by losing heat or limiting heat loss, so that your body temperature remains stable. On the one hand, our bodies will lose energy when they lose heat but, on the other, they will give off heat in high temperatures. Our bodies also sweat and that leads to damp clothing. When you’re exercising, it is important to wear clothes that are suitable for the weather, your body and the level of exertion. The 3-layer system is the ideal system for fulfilling these requirements. We split the system into 3 layers:
The base layer must transport moisture rather than absorb it. This is thermal underwear, which has direct contact with the skin and which wicks moisture to the next layer. This could be a shirt or long trousers. As a beginner, you often only need synthetic underwear (polypropylene, nylon or polyester) which dries quickly. You can find these in all colours and prices. The advantage is that they are often less expensive than technical underwear.
If you are experienced, you may invest in technical base layers. They are more fitted and will protect you during winter treks. This underwear is also made in synthetic materials, merino wool or a combination of the two. Will you be going on long, cold or multiple-day treks? Then go for soft merino wool. It doesn’t get as smelly and is better able to pick up moisture and get rid of it during exertion.
If you’ll be exercising in nice weather, you often only need a synthetic shirt made of nylon that is breathable, but also protects you against insects or wind.
The second layer is an insulating layer that breathes, wicks moisture, dries quickly and is also light. At cold temperatures, this layer helps retain body heat. A fleece is the ideal layer for this purpose.
The last and uppermost layer must be waterproof and breathable. The excess moisture from the lower layers must find a way out through the top layer. A wind or rainproof jacket is a great outer layer.