Infrared heat is a completely safe form of naturally occurrung energy that heats objects by a process called direct light conversion.  This type of energy travels 2-3 inches deep into the body and is believed to improve circulation and nourish damaged tissue.

Unlike steam saunas, this is "dry heat" which heats your body directly, not the surrounding air. The deep tissue thermal effects cause blood vessels and capillaries to dilate, promote better circulation, and help get rid of body toxins and metabolic waste through sweating. 

You can burn up to 800 calories in one 20-30 minute session.   The water lost through sweating can be replaced, the calories may not.

The improved circulation derived from infrared therapy has been associated with better cardiovascular health, speeds the healing of strains and sprains and other sports injuries by supplying more oxygen to the damaged site through improved circulation, loosens muscles prior to massage therapy, provides mild cleansing of the skin, promotes healthy skin tone and texture, and has been associated with having a positive effect on the immune system.