Why did the Plains Indians use sweat lodges?

terrible description here - the picture is also a temzcal used in South America similar to a sauna, it is not a sweat lodge.

Arohanui, I think they are referring to misuse, like the guy in New Mexico who used a rubber liner for a sweat lodge and killed a few people by overheating. a sweat lodge isn't dangerous if the person knows what they are doing and follows the right protocols

I very much doubt that was the real reason.

It reminded me of a sauna also.