How many studies support Sauna?

A well-known Finnish cohort study (KIHD) found frequent sauna bathing (4-7 times per week) was associated with substantially lower fatal cardiovascular and all-cause mortality compared with once weekly, a finding extended by related analyses from the same cohort linking sauna use, cardiorespiratory fitness, and reduced risk of sudden cardiac death. That's backed by 8 published studies in Vitaebase's database, including 2 meta-analyses, the most recent from 2023 -- a fairly substantial body of research for a single topic.