Far Infrared heat is heating through radiation. Objects heat up directly due to heat radiated by the sun without heating the air inbetween by the method of conversion.  The sun produces maximum energy in the infrared portion of spectrum.  Infrared light is not visible to the naked eye, however, some cameras can transform such light in to visible colors.  All objects radiate infrared heat, and cooler objects may not give out light but emit energy in infrared.  Humans radiate the most at wavelengths of 10 microns.  Even planets and stars emit such light.  Special sensors aboard artificial satellites can measure this light coming from astronomical objects.

Light between microwave and the visible portions of the electromagnetic spectrum is called infrared light. The electromagnetic spectrum consists of gamma rays, X-rays, ultraviolet, visible, infrared, microwaves and radio waves with varied wavelengths and frequency. The Infrared electromagnetic spectrum has three divisions according to wavelength with microns or micrometers as a measurement unit. Wavelength increases and frequency decreases from gamma rays to radio waves. Frequency also consists of temperature and energy.

‘Near infrared light’, around the size of a pinhead, is nearest to visible light while microscopic ‘far infrared’ is nearest to microwave as per wavelength. Near infrared is approximately 0.076 to 1.5 microns, medium infrared is approximately 1.5 to 5.6 microns and far infrared is approximately 5.6 to 1000 microns. Infrared rays between 7 to 14 microns can cut through the earth’s atmosphere and will warm earth. Such radiation is due to thermal radiation. After warming, the earth radiates infrared rays in the same range with peak radiation at 10.  High temperature leads to high frequencies, and a higher frequency means a shorter wavelength. Bright metallic surfaces heat up with medium and long-wave infrared radiation while clear surfaces are transparent to certain wavelengths, thereby affecting the transfer of energy. 

 

This heat is safe if you maintain necessary distance, similar to any heated surface.  Touching an infrared heated surface can cause burns, for this reason far infrared sauna kits have spacers inside to prevent direct skin contact with the heater's surface.   Hospitals use these rays to keep newborn babies warm. Although these saunas have many potential curative powers, people with certain ailments should avoid them.  Pregnant women, users of prescription drugs, patients of; Multiple Sclerosis, Adrenal Suppression cases, severe joint problems, silicone, surgical implants, hemorrhage, and women during menstruation should avoid the cardiovascular sweating intensity of these specialized saunas.