One benefit of sauna I've noticed, beyond the many you have discussed, is that it reduces the need to urinate at night. I've found that if I stop drinking water around 6pm and sauna around 8pm, I will not have to urinate while sleeping. I recognize this is due to the body being dehydrated, but is there any risk associated with that if one is drinking water all day and first thing in the morning?
Is there scientific truth in the claim that there are foods which can cause excessive mucus production? Whether they contain more histamine (dairy, aged foods, processed meats) or are histamine liberators (chocolate). Should these foods then be avoided, or do they affect individuals differently?