A sweat lodge is a Native American version of a sauna. It has the same magical and spiritual qualities as the steam room or the sauna at your neighborhood gym, which is none. So why do self-help gurus, especially the phony ones, like using them so much and claiming they are going to help your spiritual growth and enlightenment? Because that is what Native Americans used them for. In a real Native American sweat lodge, there was chanting, drumming, and often drinking a beverage that had hallucinogenic herbs added to it. The whole package was designed to aid Native Americans and was always done under the guidance of a Native American shaman. Only those who had undergone certain preliminaries were allowed to participate in the sweat ceremonies, which were usually intended to aid one in communicating with ancestors and animal spirits (totems). And the shaman was sensitive enough to people so he would know if someone had too much and would have that person led out. 
    Simply making a building shaped like a sweat lodge without the proper directions and ceremonies, and putting unqualified people in it to sweat, is not going to bring about enlightenment. Unfortunately, there are quite a few phony gurus today who grab bits and pieces from various traditions and try to claim that what they put you through, for which you pay much, will make you enlightened, successful or wealthy. Before you fall for these programs, look at the results. How many of the wealth guru's students are billionaires? How many of his customers were spontaneously cured of fatal illness? If you find no real evidence of success (the fact that followers recommend a guru is not real evidence), then you should look elsewhere. Also remember, a program that promises to make you wealthy isn't going to make you spiritual and vice-versa, so a guru who promises both, probably can't deliver either.