Sauna bathing reduces the risk of respiratory diseases: a long-term prospective cohort study.
Level 3 - non-randomized controlled study
Prospective cohort study
PubMed 28905164 · doi:10.1007/s10654-017-0311-6
What was done
Baseline sauna bathing frequency was evaluated in a prospective cohort of 1,935 Caucasian men aged 42–61 years followed for a median of 25.6 years. Incident respiratory disease cases (defined as chronic obstructive pulmonary disease, asthma, or pneumonia) were ascertained via hospital diagnoses. Multivariate hazard ratios (HRs) adjusted for major respiratory risk factors and potential confounders were calculated comparing 2–3 sessions/week and ≥4 sessions/week to ≤1 session/week.
What was found
Over follow-up, 379 hospital-diagnosed incident cases of respiratory diseases were recorded. Compared to ≤1 sauna session per week, adjusted HRs (95% CIs) for all respiratory diseases were 0.73 (0.58–0.92) for 2–3 sessions/week and 0.59 (0.37–0.94) for ≥4 sessions/week. For pneumonia specifically, adjusted HRs were 0.72 (0.57–0.90) for 2–3 sessions/week and 0.63 (0.39–1.00) for ≥4 sessions/week.
Why it matters
This study provides the first long-term prospective evidence linking regular sauna use to a lower risk of both acute and chronic respiratory conditions in a dose-dependent manner.
Limits
The study included only middle-aged Caucasian men, limiting generalizability to women, younger people, and other ethnic groups. Sauna bathing habits were assessed only at baseline and could have changed over the 25.6-year follow-up. Only hospital-diagnosed cases were captured, missing milder outpatient cases, and residual confounding from unmeasured lifestyle or socioeconomic factors remains possible.
Cited by
- supports A Finnish prospective cohort study found that men who used a sauna 2 to 3 times weekly had a 27% lower risk of pneumonia, and those using it 4 to 7 times weekly had a 41% lower risk compared to infrequent users.