Far Infrared is radiant heat which we ourselves as human beings naturally emit. This is the same heat we feel from an environment warmed by the sun. It is completely natural and 100% safe.
Human & animal sense of comfort has evolved from radiant heat from the sun. Our skin naturally tans, reflects and prompts us to avoid the suns hottest waves, Near (Shortwave) infrared. The waves we find most comfortable are those that are absorbed by our environment and radiated back – called Far and Medium (or Longwave and Middle) infrared.
Far Infrared is what our skin and common materials in our environment absorb and emit the most efficiently and 100% naturally.