Which Base Layer is the Warmest?

Under certain weather conditions, just wearing a good coat is not enough to keep you warm. If you live in a frigid climate where the thermal sensation differs significantly from the temperature in a thermometer. To get around this situation, which can ultimately compromise the joys of winter, several fabrics were developed that are used in different types of clothing. The overlapping of several pieces of clothing is called the "layering system" because it resembles that of an onion.

The layer system is divided into 3 fundamental parts: the base layer or first layer, the thermal or intermediate layer, and the external or third layer. All layers must, as a priority, be breathable, so when choosing each of the skins, it is essential to notice this detail.

The base layer, also known as the first layer, is a garment that resembles a glove but for the entire body and is lightweight. This piece is known as a second skin because it snug fits the body with no seems. To function correctly, it must be a micro-textured fabric. In other words, no natural fabrics like cotton. There are different fabrics for different temperatures. The lighter the weight, the easier it is to transfer sweat.  

Most thermal base layers consist of a polyester/ spandex blend. Usually, they accompany a fleece lining to make it comfortable and warm. Because of the elastance, the thermal clothing is four-way stretchable and doesn't restrict movement. Synthetic fabric for thermal underwear is ideal for frigid climates. As mentioned, it is usually polyester and spandex, but also lycra and nylon. These materials offer a good balance between moisture wicking and heat retention.

Merino wool is the gold standard for base coats because of its many desirable qualities. However, more expensive brands often feature Merino wool, which is warm, absorbs moisture, and even has odor-reducing properties. Although Merino sheep originated in Spain, nearly 80% of merino wool is now obtained from sheep raised in Australia and New Zealand.

Silk is a lightweight fabric option suitable for when the weather is cold but not too cold. This natural fabric, like cotton, is not used in its pure form but is combined with synthetic yarns. It has a soft texture without too much bulk, but it's not so good at quickly drawing moisture out of the body.

Pure cotton yarns are practically not used in the production of fabrics for thermal underwear, as cotton quickly absorbs and retains moisture for a long time. Most of the time, the cotton threads in the material are combined with synthetic ones. Pure cotton underwear can be used in cases where physical activity does not involve active actions that cause profuse sweating.

Fabric texture also plays a role in the functionality of thermal base layers. The extraordinary interweaving of the threads makes it possible to obtain a fabric of 1 to 3 layers. In addition, using different weaving techniques, it is possible to get areas with varying textures in the underwear. This will provide maximum comfort in places of greater or lesser perspiration on the body.