First of all, it is an error to talk about “infrared sauna”, being the correct diction “infrared cabins”. Finnish saunas and infrared cabins are different.
Actually the sauna is a natural treatment: its beneficial effects, both on psychological and physical level, are a heavy sweating and, as consequence, the elimination of liquids, toxins and lactic acids.
During a treatment with infrared it is difficult to perceive the actual action, being the temperature lower than the traditional sauna. Inside the infrared cabin the temperature reaches 50/55 °C, the infrared gets into your skin and raises the body warmth.