April 30, 2026
The study people are quoting when they talk about sauna and heart health is a Finnish cohort published in JAMA Internal Medicine in 2015. It followed 2,315 middle aged men for a median of about 20 years.
The finding that travelled was the frequency gradient. Men using a sauna four to seven times a week had substantially lower cardiovascular mortality than men using it once a week. Session length mattered too, with longer sessions tracking better than short ones.
Worth being honest about what that is and is not. It is an observational cohort in one country with a specific sauna culture, all male, and it cannot prove the sauna caused the difference. People who sit in a sauna five times a week may differ in a dozen other ways.
What it does support is unremarkable and useful: regular heat exposure looks good for you, and regular beats intense. Our recovery room runs at 60 degrees for that reason. It is warm enough to matter and mild enough that you will actually come back on Thursday.