I had one session in a Far Infrared Sauna
. It was amazing. My naturopath also put me on a chi machine at the same time so I'm not entirely sure what did what, but while I was in the sauna, it felt wonderful and I felt my body just relaxing like it never had before.
The following two nights I had the best sleep I have had in years. Unfortunately, after that I went back to sleeping badly but I also think it may have caused some herxing for the following week.
I definitely plan on doing more sessions with the sauna.