The sun is an excellent source of Infrared Heat, and it`s the reason that you seem to instantly relax when your skin is touched by it.
This instant relaxing is similar to the feeling experienced in an infrared heat based saunas. You can stay in an infrared sauna longer and reap greater benefits because the air around you does not reach blistering temperatures like in a traditional sauna.
Athletes have been known to use this type of heat to relieve aches, pains and strains, and also to help move along the healing process because it is believed to help make circulation more efficient. As you may know, wounds heal faster with better circulation, and this is also true of muscle and tissue trauma.