an infrared sauna will give you the good parts of the sun without the harmful UV rays
as far as regular sauna's like at the gym that are public, in actuality they are a health hazard. you know how many disgusting naked men have sat in there sweating ? it is more filthy than a kids swimming pool at the Y.
if you are going to use a sauna use a private one at your home to sweat out toxins but make sure you are hydrating after
or go mow the grass in the middle of the day lol