Is Sauna good for cardiovascular health?

Yes — the evidence for this is strong. 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 reflected in an evidence score of 71/100 for its role in cardiovascular health, drawn from 9 studies, with an estimated impact on longevity rated moderate (63/100).