###### Abstract
In addition, the weight of the new system was lower compared to the others, which had an impact on improving physical fitness. [PERSON] and [PERSON] [11] evaluated an electrically heated vest (EHV) using a thermal dummy under conditions simulating a cold environment. In the study, the dummy was used to assess the performance of such vests used with a three-layer set of clothing. It was demonstrated that an EHV can change the uniformity of thermal insulation of the entire clothing set. It was pointed out that a higher heating temperature leads to lower heating efficiency as a result of greater heat loss to the environment. It was observed that heating efficiency decreased from 55.3% at 0 \({}^{\circ}\)C to 27.4% at 21 \({}^{\circ}\)C when heating power was set to 13 W. Moreover, the authors suggested setting the heating power to 5 W at 0 \({}^{\circ}\)C and to 13 W at 21 \({}^{\circ}\)C to provide thermal comfort to the user. [PERSON], [PERSON], and [PERSON] [12] evaluated electrically heated gloves designed to relieve pain in patients with vasospastic disorders. They proved that such gloves provided many significant benefits for patients suffering from Raynaud's syndrome (numbness of the fingers and toes, as well as the nose and auricles) and other vasospastic conditions. Other researchers have considered monitoring and measuring biosignals from people working in cold environments. If the body temperature fell below a certain level, then the heater placed in the clothing automatically turned on, providing the user with adequate thermal comfort [13]. Another example is a vest equipped with heating inserts incorporating e-textiles. The inserts were made of various conductive yarns using hot air welding technology [5]. The heating inserts based on e-textiles were tested to assess their heating properties using different direct current (DC) values. During work implementation, an electrical module composed of a control and power management system was designed and fabricated. At the next stage, the electric module was integrated with the heating insert intended for use in the vast. To produce the vest, [PERSON] and [PERSON] [5] recommended the use of fabric with a canvas or oblique weave with a surface mass of 250 g/m\({}^{2}\). They found that the composition of the materials from which the vest is made affects the heating properties of the inserts. For example, they found that the heating capacity of woolen fabric is higher than cotton. Thermoplastic fabrics, namely, polyamide and polyester coated with polyurethane, were used as conductive fabrics in combination with lithium batteries with 7.4, 9, and 12 V nominal voltages. Tests on volunteers were conducted to observe and monitor the heating efficiency of the produced vest in real time--a thermal imaging camera recorded the front and back of the vest after 10 min after turning on the heating unit and immediately after the removal of the vest. The temperature of the front of the vest reached 23.5 \({}^{\circ}\)C and the back--25.5 \({}^{\circ}\)C--30 s from the moment of putting on the vest. The vest was observed to heat up quickly, and the heat was distributed evenly over its whole surface. Nowadays, most electrically heated clothing available on the market is based on built-in heating cables, which cause some problems. Currently, the heating element is mainly implemented in the form of a panel/heating insert, which means that it cannot be integrated with the human body, causing limitations to the user's mobility. Another significant drawback is that the heating wires tend to break. Temperature control systems should be properly designed and deployed so that the temperature could be changed in a controlled manner [14]. [PERSON] et al. [15] also pointed to a problem related to the capacity of batteries used in electrically heated clothing. They observed it in the course of their research on an electrically heated vest in which the battery lasted only 2 h. [PERSON] et al.