[Excerpt] Introduction: Humans are endothermic organisms and have much higher basal energy consumption, which is mainly necessary to keep their body temperature constant within a wide range of different environmental temperatures. The human body temperature is around 37 °C in the body core such as cranial, thoracic, abdominal cavities and in the extremities, the temperature is lower (28-36°C) [1]. Especially in active sports, the muscles produce heat from metabolic activity and this causes greatest thermal stress during exercise. [...]This work was supported by FEDER funds through the Competitivity Factors Operational Program (COMPETE) and by national funds through FCT–Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007136. We would like to thank Nadine Häußermann and Silke Küblbeck for their kind support
