The most difficult concept to explain to new infrared sauna researchers is that an infrared sauna does not use hot air to produce a sweat. Rather, it uses invisible light on the far infrared spectrum that comes off as radiant heat. Because it is invisible light it travels the same way that light does–in a straight line. What this light does is penetrate into your skin, it is absorbed, and then it raises your core body temperature from the inside. Have you ever been cold in the shade or inside your home then walked outside into the sunlight and felt that internal warmth radiating through your body? That is far infrared radiant heat! When you are in the sauna you are very slowly raising your core body temperature over the span of your sauna session. The starting temperature that we recommend for getting in the sauna is 110 degrees. At the end of a half an hour session, the temperature will be around 120-125 degrees. In the meantime, your core body temperature will have risen a few degrees producing a sweat that is full of toxins and heavy metals.