Sometimes when you step outside into the sun you can feel warmth overcome you from the inside out. This feeling is caused by far infrared rays, an invisible light which is on opposite side of the spectrum of harmful ultraviolet rays. It is the same light that plants use to photosynthesize in order to feed. This plant dependency of far infrared can be found in the human body as well. Science has been able to focus FIR and utilize them to improve our wellness levels.