Regular use of saunas could be key in reducing stroke risk, a new European study reports.
Baseline sauna habits of 1,628 men and women (age 53–74 years; mean 62.7) without prior history of stroke were included in the Finnish Kuopio Ischemic Heart Disease prospective cohort study. Three sauna bathing frequency groups were defined: 1, 2-3 and 4-7 sessions per week.
During a median follow-up of 15 years, 155 strokes occurred (90 in men, 65 in women), with the majority being ischaemic. The authors uncovered that the use of a hot, dry Finnish-style sauna 4-7 times a week led to a 60% reduction in stroke over the follow-up period. Stroke rates per 1,000 person-years was 2.8 for this group, compared to 8.1 in the once-weekly sauna group.
The association between frequency of sauna bathing and the risk of stroke was not modified by age, sex, or other clinical characteristics. Furthermore, after adjustment for established cardiovascular risk factors or other potential confounders, the hazard ratio (95% confidence interval) was 0.39 (0.18-0.84). This persisted after adjustment for physical activity and socioeconomic status.
Finnish-style saunas, typically featuring dry air at 80-100°C, have long been thought to lower blood pressure. What’s more, stabilisation of the autonomic nervous system is also purported, reducing inflammation, oxidative stress, arterial stiffness and vascular resistance. Clubbed together, these factors could drive the reduction of stroke risk as observed in the study.
Taken as a whole, the data suggests that frequent use of Finnish-style saunas could offer protective benefit for new-onset stroke. However, an accompanying editorial cautions that the results must still be interpreted carefully. Specifically, in some individual circumstances, sauna use may actually contribute to stroke or transient ischaemic attack due to hypotension, dehydration, arrythmia or haemoconcentration, especially if alcohol has been consumed prior to bathing.