That makes much more sense. I googled sona and was totally confused.
Anyway, no, saunas and steamrooms do not help with weightloss. The water weight you do lose is put on the moment you drink something as your body is rehydrating.
However, I LOVE steamrooms. My skin feels fabulous, it loosens my muscles and I find it very relaxing. In a roundabout way it does kind of help with weightloss as I look at it as a "treat" after working out