New Research Strengthens the Case for Sauna and Immune Health

Professor Jari Laukkanen's research group at the University of Eastern Finland keeps adding to the evidence base for sauna's health benefits. The latest findings, presented ahead of the World Sauna Forum 2026, focus on the immune system: regular sauna bathers showed lower levels of C-reactive protein (CRP, a marker of systemic inflammation) and reported fewer flu symptoms compared to people who don't use saunas regularly.

What the Research Shows

The study involved approximately 100 participants and measured inflammatory biomarkers alongside self-reported illness frequency. The key findings: regular sauna users had lower CRP levels and got sick less often. Elevated CRP is associated with acute systemic inflammation, so lower baseline levels suggest a calmer immune response, not a suppressed one.

This builds on Laukkanen's earlier work, including the landmark Kuopio Ischemic Heart Disease Risk Factor Study (published in JAMA Internal Medicine, 2015), which tracked over 2,300 Finnish men for 20+ years and found that frequent sauna use (4-7 times per week) was associated with a 40% reduction in all-cause mortality compared to once-weekly use.

The immune findings are still early, but they're consistent with what the cardiovascular data has been telling us for years: regular heat exposure appears to have broad, systemic health benefits.

Laukkanen Research Highlights: Kuopio KIHD Study: 40% lower all-cause mortality for frequent sauna users (JAMA Internal Medicine, 2015). New findings: lower CRP levels and fewer flu symptoms in regular sauna bathers. Reduced arterial stiffness in regular sauna users. Research funded by Finnish Funding Agency for Innovation.

Context

Laukkanen has become the most-cited researcher in sauna health science, and his work is frequently referenced by both the medical community and the sauna industry. He is expected to speak at the World Sauna Forum 2026 in Jyvaskyla, Finland (June 9-11).

The immune research is still in its early stages and the sample size is modest. More work is needed before drawing broad clinical conclusions. But the direction is clear and consistent with the larger body of sauna health evidence.

For a deeper look at the newest mechanistic data, including white blood cell and interferon shifts measured during a single heat exposure, see our follow-up analysis of how sauna acutely affects immune cell activity.