## 5 Additional Functionality of Medical Compression Garments
However, the main aspects of comfort are psychological, thermos-physiological and neurophysiological [116]. Since the assessment of the level of psychological comfort is mainly based on a person's subjective feelings, studies of the comfort of textile materials and products relate to a greater extent to issues of ensuring thermos-physiological and neuro-physiological comfort (which in other studies is called tactile or sensory) [117]. Sensory comfort is characterised by what a person experiences as a result of the interaction of clothing and skin under certain atmospheric conditions. The feeling of neuro-physiological comfort is influenced by the texture of materials, their surface roughness, rigidity, and ability to collapse and create wrinkles [118; 119]. There are three main skin irritants: mechanical contact with external objects, temperature changes caused by heat flows, and chemical influences. In response to various stimuli, skin receptors can produce sensations of heat, cold, touch or pain. The neuro-physiological aspect [117] of textile clothing comfort is also influenced by such characteristics as prickliness and scratchiness, stiffness, softness, smoothness, roughness, friction, and the tendency of the material to cause itching (itchiness), as well as tactile properties and whether the material is warm or cool to the touch, whether it causes a feeling of dampness (dampness sensations). The prickliness is associated with the presence of hard fibres rising above the surface of the fabric. The degree of adhesion of a fabric is most influenced by characteristics such as the supporting surface, wettability and the area of contact of the fabric with the skin. Wet adhesion occurs due to sweating. A warmth to the touch is felt when the garment is first picked up or put on. The feeling of roughness depends both on the geometry of the surface of the fabric and on the area of contact between fabric and skin and the force interaction between them. Because of ageing, the temperature of the deep muscles decreases, and it can profoundly change motor function and performance [95]. For example, local knee heating (up to 44 \({}^{\circ}\)C next to skin temperature) for young and aged, especially, adults can reduce pain and increase mobility [120]. Heating therapy helps to increase skin blood flow, blood volume and oxygen saturation, stimulates blood circulation and, therefore, reduces joint stiffness and pain release in joints, and consequently leads to the overall improvement in joint mobility during movement [121]. Various heating elements and techniques can be used to realise the heating function in orthopaedic compression supports, such as heating tubes or plates attached to the surface of the support, electro-conductive metal wire or electro-conductive yarns embroidered on the surface of the support or directly incorporated into the structure of the support by weaving or knitting. Realisation of an externally mounted heating plate or tube is technically not very difficult, however, it has an essential disadvantage--it is an additional rigid element that has a significant impact on the overall compression generated by the product. The embroidered heating element, using electrically conductive threads, also has a significant effect on the overall elasticity and compression of the product. The best solution to realise the complex compression heat therapy is to incorporate electro-conductive yarns directly into the textile structure [122]. Conductive fibres, filaments and yarns can be classified into two main groups: those that are originally conductive and others that are specifically treated in order to reduce their electrical resistance and increase their conductivity. Originally, conductive yarns were formed from electrically conductive metals, such as stainless steel, copper, aluminium, carbon, fine filaments, etc. The conductivity of such yarns usually is very high; however, they are characterised by higher rigidity compared to conventional textile yarns.