This is a linkpost for https://www.eurekalert.org/pub_releases/2016-12/uoef-fsb121616.php
"The more frequently saunas were taken, the lower was the risk of dementia. Among those taking a sauna 4-7 times a week, the risk of any form of dementia was 66% lower and the risk of Alzheimer's disease 65% lower than among those taking a sauna just once a week. "
that seems more effective than any single medical intervention i have seen, even the sonogram and strobe light tech were less efficacious than this.
As a very shitty theory; the results might be able to be explained by frequency of exercise associated with sauna use. i.e. if I go in the sauna every time I gym and I gym 7 days a week instead of 1 day a week I can presume that means I am healthier or am more likely to be healthier.
...Previous results from the KIHD study have shown that frequent sauna bathing also significantly reduces the risk of sudden cardiac death, the risk of death due to coronary artery disease and other cardiac events, as well as overall mortality. According to Professor Jari Laukk