Due to the infrared radiation warmth is generated on the skin surface. This warmth is continually transported to the interior of the body by the circulation of the blood supply. This results in a continuous, gradual increase of the body core temperature.
The body begins gradually increasing the blood supply to the periphery (i.e. muscle and skin). After about 10 minutes the guests at the Wellbeing Hotel in the Stubai feel an increase of the body core temperature by 0,1 °C, after about thirty minutes the body core temperature increases by about 0,2 - 0,3 °C and perspiration sets in.