A BASE OR THERMAL LAYER IS AN ELEMENTARY AND FUNDAMENTAL LAYER FOR ALL SPORTS ACTIVITIES.
During physical activity your body will warm, as a result, its natural cooling system will kick in to regulate your core temperature; your body will begin to perspire. When exercising in cold weather conditions, it's particularly important to draw perspiration away from the body as quickly as possible as damp clothing may cool the body too quickly. A thermal base layer in this case performs its functions as a layer that wicks perspiration away from your skin while simultaneously insulating. Thermal garment should be worn straight on the skin so it can keep you warm and dry.
Functionality Of The Garment
Thermal garment provides this unique attribute thanks to the used material, which does not absorb the humidity and instead lets it go through towards the external layers of the clothing and out.
How does it work: if you apply a drop of water to a cotton shirt, the water soaks into the fabric and takes a relatively long time to dry. But if you apply a drop of water to a polyester shirt, water remains on the surface and therefore dries much faster. The structure of the fabric is thus fundamental in maintaining comfort.
Materials for thermal garments are produced in varying combinations and thicknesses; but the aim is always to achieve an ideal balance between the removal of moisture, while also retaining a sufficient (but not excessive) amount of heat. For example, a less thick variant of the material is suitable for biking in the summer, as the highest amount of ventilation is needed. In the same way, a thicker variant of the material would be more suited to skiing in the winter, where retaining body heat is more immediately important than ventilation.
The most common materials for a base thermal layer are polyester and polypropylene, as they retain almost no moisture, are lightweight and relatively comfortable.
Cotton on the other hand, retains a lot of moisture, making it unsuitable as a material for technical sports clothing.
Merino wool as a latest trend
Merino Wool is another alternative for the effective removal of perspiration, because of its low water absorption and excellent thermal insulation properties, all the while remaining pleasant to the touch - like cotton. Merino wool is also naturally antibacterial, so the buildup of bad odour from perspiration is minimal. People with sensitive skin may initially find this fabric itchy or otherwise irritating but after several washes this feeling should lessen.
Proper Use of Base Thermal Layers
• To ensure its proper function, the base thermal layer should encircle the body; fitting comfortably but not too loosely. Higher quality (usually more expensive) garments usually fit better because of the form-fitting design and elastic materials used to produce the clothes.
• Full equipment is needed for the right function of the garment. Even the best thermal garment will be inefficient if used over a cotton underwear, which would concentrate the humidity in the most delicate spots of the body.
• It's always better to layer - two or three layers are always more versatile than one thicker layer.
• It is physically impossible to keep you dry while exerting in extremely humid weather as the humid air cannot absorb the humidity from your clothes.
• When you set out for a light intensity activity in cold weather, dress so that immediately after leaving the heat of your home, you feel slightly chilly. Once you start exerting yourself and are at 'operating temperature', your clothing should insulate you accordingly, without the overt perspiration you would have if over-dressed.
• Base thermal garments should be washed according to the manufacturer's instructions on the labels, though as a general rule, it's not recommendable to use fabric softeners. Beware of combining items containing Velcro patches (or strips) with fine fiber garments as the Velcro will break down delicate fabrics with each wash.