Thermal underwear can be defined in two basic ways. The first is to regard this term as a synonym for functional underwear. However, for simplicity, we will use the second variant and define thermal underwear as clothing, whether in the first or second layer of functional composition, which is made of functional materials and serves to maintain the body's thermal comfort while also wicking away excess moisture and sweat away from the body.

Directly on the body or over underwear

Under our second definition, elements of clothing for both the upper and lower body fall, which can be worn either directly on bare skin or over already worn functional underwear. In the first case, this thermal underwear will work together with the underwear as an absorptive layer.

The ideal material that perfectly fulfills the function of thermal underwear is merino wool, which can warm even when wet and at the same time beautifully wicks moisture to other layers of clothing. From merino wool, you can get, for example, a long-sleeve shirt, but also bottoms. Another option is to use polyester, either on its own or in combination with cotton or elastane, or both.

On top of the underwear, you can then wear elements of the second functional layer, called the insulation layer. In this case, it is appropriate that the thermal underwear has a thick structure and is not too thin. The ideal material that will fulfill the function of insulation in this case is fleece.

For winter and even for a sleeping bag

Functional thermal underwear can help you eliminate the possibility of getting cold in extremely low outdoor temperatures. And this regardless of whether you are going for a walk, on an expedition, or on a military mission. Naturally, it is advisable to combine thermal underwear with a winter jacket or winter pants to make the functional composition of the clothing perfect.

If you plan to bivouac in cold weather, you can keep the thermal underwear on even when you go to sleep. In a sleeping bag, it serves as insulation – but be careful, it is necessary to ensure the correct size of the sleeping bag, so that there is still a sufficient layer of air between your body dressed in thermal underwear and the sleeping bag for thermal insulation.

At Rigad.cz, you will find functional thermal underwear from established brands that are tested by members of civilian expeditions and military missions. Carefully chosen materials and quality cuts ensure that you will feel comfortable in your new thermal underwear while also being protected from external influences.