
Thermal underwear - what is it and what is it used for?
The very term "thermal underwear" is initially misleading. After all, if it is "thermo" - then it should warm up. But modern underwear for sports or even just for an active lifestyle has completely different functions and the task of "warming up" is far from the most important here. But obviously, the word thermal underwear sounds much better than water-repellent or antibacterial, which, in general, also does not reveal its full functionality.
So, thermal underwear is first and foremost underwear, a kind of "first layer". For different conditions and needs, thermal underwear is made of synthetic fabrics, natural or mixed fabrics. The complex structure of the tissue is made in such a way as to ensure that excess moisture is removed from the body and retains the body heat generated by its own body. Many do not even think that moisture can cause frostbite and discomfort. Therefore, the removal of moisture is the most significant difference between thermal underwear and ordinary clothes.

What is thermal underwear?
The main functions of thermal underwear are:
It does not absorb, but removes excess moisture (sweat) from the surface of the skin. In contrast, cotton underwear absorbs moisture well, gets wet quickly and is difficult to dry, which leads to additional cooling of the body;
Regulates heat transfer - retains heat and at the same time prevents overheating;
It does not restrict movement, the fabric is elastic. Underwear is designed taking into account the active use during sports;
Provides comfort in all modes of activity (stays dry and soft);
Maintains body hygiene for a long time, prevents the appearance of the smell of sweat.
How it works?
Depending on its purpose, thermal underwear can perform several functions - to remove excess moisture, to keep you warm or both. During physical activity, a sufficient amount of moisture is released from the human body, which, accumulating in the fabric of ordinary underwear, seriously damages its thermal insulation properties. In addition, precious energy is additionally consumed to heat and evaporate this moisture.
Thermal underwear is made of complex, specially developed fabrics by special technologies. To ensure all the above requirements, manufacturers of thermal underwear use materials with a special structure for knitting. Usually such tissue has a cellular structure, while the cells adjacent to the body remove moisture from it, and the upper ones work to maximize its distribution on the surface and rapid evaporation due to the capillary effect. In this way, your energy is not used to heat the accumulated moisture, and the generated heat does not go outside.
In addition, on sale you can find thermal underwear consisting of materials with different degrees of density, local compression stimulates blood circulation and maintains muscle tone.
Composition of thermal underwear. What is it made of?
Wool and cotton, so loved by our grandmothers, no longer seem so indispensable. There was a time when all thermal underwear was made of traditional wool. But the coat is different. Cheap wool strongly binds the body, its products are heavy and do not remove moisture at all.
Over the last few years, a number of specialized laboratories have been working to ensure that technological advances in the production of synthetic materials do not stand still. Modern fabrics, although synthetic, breathe well and also dry quickly and are hypoallergenic. Hollow synthetic fibers and fabrics from them push the linen from natural fibers far back.
Thus, today thermal underwear is produced mainly from synthetic fibers, natural fibers are used only as additives. New Zealand merino wool stands alone.
Synthetic fibers
"Synthetics" is remarkable in that it removes and practically does not accumulate moisture, and the remaining minimum evaporates quickly. Synthetic thermal underwear is more durable and less susceptible to deformation. Such tissues also inhibit the growth of sweat-causing bacteria. Some manufacturers sometimes use special impregnations to increase the antibacterial and antimicrobial properties of synthetic thermal underwear.
The main materials are: Polypropylene (PP), polyester (PES), polyamide (PA), polyacrylic, elastane, nylon and others.
Polypropylene - better than other materials, removes moisture from the skin without getting wet. But it is not recommended to wear thermal underwear made of 100% polypropylene for a very long time and even more to sleep in it, because polypropylene will dry the skin unnecessarily.
Polyester - considered the best material for thermal underwear - pure or with impurities. In terms of fiber structure, polyester (PES) is similar to cotton. Things made of polyester last a long time, always stay soft and absorb moisture well.
Polyamide - thermal underwear made of polyamide is distinguished by its smoothness to the touch and lightness. Almost all variations of seamless underwear are made of polyamide.
Elastane - as its name suggests, the thinnest fibers of this material are added to thermal underwear to increase elasticity and durability. The higher the proportion of elastane in the composition, the better the clothes are stretched without leaving traces of stretching.
Natural fibers
Of the natural fibers for the production of thermal underwear, cotton, wool and silk are most often used. The properties of natural fibers are very important and often irreplaceable and are often used in combination with synthetic materials.
Cotton - The special properties of cotton fibers are that cotton removes moisture from the skin faster than other materials without even touching it, but it accumulates and holds very tightly. The retained moisture in the skin constantly cools it until it completely evaporates. It evaporates, consumes body heat. For this reason, manufacturers combine cotton with synthetics: in this way, moisture is removed quickly and the skin remains quite dry. So leave 100% cotton underwear for everyday wear and sleep, not for sports.
Merino wool - its warming effect is known to all. Wool fibers provide micromassage to the body, which increases the intensity of blood circulation in the skin capillaries. The service life of the wave depends on the quality of its thread. For a long stay in the cold, wool is indispensable. In addition, wool has natural antibacterial properties, which makes its products resistant to odor.
Silk - gives the underwear high strength and abrasion resistance. In addition, silk underwear is extremely pleasant for the skin. In the production of thermal underwear silk is used only in combination with synthetic materials and quite rarely.
What thermal underwear do you need?
The choice of type of underwear directly depends on three factors: air temperature, intensity of the load and the personal reaction of the athlete to heat and cold. Based on this, manufacturers of thermal underwear offer models for sports and fitness, as well as for everyday wear in different versions - cool (cold, for hot conditions), light (light, for summer), warm (warm, for cold conditions), x- warm (very warm in severe winter conditions).
Choice of thermal underwear
For winter sports, it is preferable to combine polypropylene thermal underwear with the addition of cotton or wool. Going skiing or snowboarding means a regular change of active loads (downhill) and a state of rest (climbing the lift, lunch in a cafe or bar). Therefore, in cold conditions, it is necessary that your thermal underwear not only removes moisture, but also retains heat.
If you are a climber, hiker, kayaker, yachtsman, then your choice is almost 100% limited to synthetic fabrics, both in winter and summer. In fact, only such underwear is able for many days with continuous wear to provide comfort and warmth. Although, according to technologists, woolen merino underwear will also cope well with all these tasks.
If you want to buy thermal underwear for everyday wear - just choose what you like. It is only necessary to determine the density of the material. Each of them is suitable: cotton, wool, combined or purely synthetic. The main thing is not to get lost in the thickness of the fabric. Manufacturers usually put special labels to indicate the degree of heat of a particular thing.
If you expect to be outdoors for a long time in cold weather without active movements, or simply belong to the category of "frozen" people, your choice is woolen or fleece underwear.
How to choose the size of thermal underwear?
Thermal underwear should ideally fit snugly on the body. Otherwise, the radiated moisture will not be removed and collecting in drops, it will drain on the surface of the skin. Reinforced flat seams and double cuffs allow tight and comfortable adhesion of thermal underwear to the body and prevents friction. In addition, the tight fit makes it easier to put on an extra layer of clothing over thermal underwear.
How to choose the size of thermal underwear?

You should not buy thermal underwear, focusing only on the sizes indicated on the labels. Before you buy thermal underwear, don't forget to try on a set - take a walk, sit down, wave your hands. Experienced consultants in a specialty store can always tell you how this or that model should sit. But don't forget to listen to your feelings. Don't press? Not lubricated? The seams do not rub?
What sensations does a person feel in thermal underwear?
A person's feelings, of course, depend on the nature of his occupation. Each sport has its own specific load intensity. Take, for example, the usual winter run. The load on the body is evenly high. If the thermal underwear is chosen correctly, the back and lower back will remain dry. But what about tourism? The load in this case is uneven, torn. Periods of intensive work combined with complete rest. It is extremely difficult to find a warm shower in nature at the end of the day, and taking a few sets of changeable underwear with you on a trip is not a very promising prospect, every gram counts! And you also need to take into account the strong differences in air temperature in the morning, afternoon, evening and night.
The neck is very indicative of the issue with thermal underwear. Often there, right on the top of the "thermal t-shirt", the line of dryness crosses if your thermal underwear does not do its job
Thermal underwear care
Thermal underwear should be washed in warm water at a temperature not exceeding 40 ° C, with soap or washing powder by hand or in a washing machine in "gentle" mode with the addition of rinse aid with antistatic additive.
Rinse thoroughly after washing. It does not need to be squeezed or centrifuged. It is necessary to allow the water to drain and dry without the use of aids.
Do not dry thermal underwear on heated surfaces and near an open flame, it is best to dry in a well-ventilated room with low humidity.
Linen made of polypropylene is strictly forbidden to iron, dry in the dryer, on the radiator or over a fire.
Do not store thermal underwear near heating and lighting devices, in unventilated rooms, in rooms with high humidity;
Remember that the material, heated to a temperature above 60 ° C, irreversibly loses its properties
