Laukkanen’s Research Links Regular Sauna to Lower Inflammation and Pneumonia Risk

Professor Jari Laukkanen’s research group at the University of Eastern Finland keeps adding to the evidence base for sauna’s health benefits. Its immune findings come from the same cohort of middle-aged Finnish men behind its heart research: men who took more saunas had lower levels of C-reactive protein (CRP, a marker of systemic inflammation), and frequent sauna bathers had a lower risk of pneumonia.

What the research shows

In 2,084 men aged 42 to 60, average CRP was about a third lower among those who took four to seven saunas a week than among once-a-week bathers (1.65 against 2.41), and the inverse association held after adjusting for age, body mass index, blood pressure, smoking, diabetes, cholesterol, alcohol and physical activity, per a 2018 paper in the European Journal of Epidemiology.

A follow-up of 2,264 men over a median 26.6 years recorded 528 cases of pneumonia. Men who took two to seven saunas a week had a 21% lower risk than men who took one or fewer (hazard ratio 0.79), and men with high CRP who took saunas often showed none of the extra pneumonia risk seen in high-CRP men who rarely did, per a 2022 paper in the Journal of Cardiopulmonary Rehabilitation and Prevention. Both studies are observational: they show associations, not that sauna causes the difference.

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 are consistent with what the cardiovascular data has shown for years: regular heat exposure appears to have broad, systemic health benefits.

Context

Laukkanen’s work is frequently referenced by both the medical community and the sauna industry.

The cohort is all men, most of them middle-aged Finns, and the findings are associations. More work is needed before drawing broad clinical conclusions, including in women and in trials that assign sauna use.

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.