Sauna for cerebrovascular disease / history of ischemic stroke or TIA
Evidence review
Overview
In the KIHD cohort of Finnish men and women without prior stroke, using a sauna 4-7 times per week was associated with a lower risk of incident stroke than once weekly, mainly ischemic stroke. In a Japanese cohort of 30,076 adults without cardiovascular disease, almost daily hot-tub bathing was associated with lower incidence of stroke, including cerebral infarction and intracerebral hemorrhage. These are observational associations in stroke-free populations. No clinical trial has evaluated sauna in patients with established cerebrovascular disease, and isolated case reports describe stroke occurring during sauna bathing.
Key findings
- KIHD (n=1,628, mean age 62.7, 14.9-year follow-up): incident stroke HR 0.38 (95% CI 0.18-0.81) for 4-7 vs 1 session/week after adjustment incl. physical activity and SES.
- Japanese JPHC cohort (n=30,076, aged 40-59): almost daily tub bathing vs 0-2 times/week, total stroke HR 0.74 (95% CI 0.62-0.87); cerebral infarction HR 0.77 (0.62-0.97); intracerebral hemorrhage HR 0.54 (0.40-0.73); no association with subarachnoid hemorrhage.
- No trials in patients with prior stroke or TIA were identified.
Every study we reviewed
2 found benefit · 1 found harm
Each study was checked on PubMed. The colored edge shows the direction of the result. The research library lists 10 studies on stroke, across all heat and cold therapies, including case reports and older work not graded here.
Sauna bathing reduces the risk of stroke in Finnish men and women: A prospective cohort study.
Kunutsor SK et al. Neurology. 2018. PubMed 29720543 · DOI · Free full text
- Who
- Finnish men and women aged 53-74 without known stroke (KIHD)
- What
- Self-reported sauna frequency 1 vs 2-3 vs 4-7 sessions/week
- Protocol
- 1 vs 2-3 vs 4-7/wk
- Measured
- Incident stroke
- Result
- 155 strokes. HR 0.39 (95% CI 0.18-0.84) for 4-7 vs 1 session/week after CV risk factor adjustment; 0.38 (0.18-0.81) after further adjustment for physical activity and SES; not modified by age or sex.
- Limitations
- Observational; excluded people with prior stroke; few events in highest-frequency group; hemorrhagic stroke events few.
Habitual tub bathing and risks of incident coronary heart disease and stroke.
Ukai T et al. Heart. 2020. PubMed 32209614 · DOI
- Who
- Japanese adults aged 40-59 without CVD or cancer at baseline (JPHC Study), followed 1990-2009
- What
- Habitual hot-water tub bathing: almost daily vs 0-2 times/week (self-reported)
- Protocol
- 0-2 vs 3-4 vs almost daily/wk
- Measured
- Incident stroke (and coronary heart disease)
- Result
- Almost daily vs 0-2 times/week: total CVD HR 0.72 (95% CI 0.62-0.84); CHD HR 0.65 (0.45-0.94, P trend 0.065); total stroke HR 0.74 (0.62-0.87); cerebral infarction HR 0.77 (0.62-0.97); intracerebral haemorrhage HR 0.54 (0.40-0.73). No association with sudden cardiac death or subarachnoid haemorrhage.
- Limitations
- Observational association; single baseline questionnaire; residual confounding possible; tub bathing, not sauna; general population without prior CVD.
Sauna stroke syndrome.
Heckmann JG et al. J Stroke Cerebrovasc Dis. 2005. PubMed 17904014 · DOI
- Who
- 64-year-old man with large cerebral infarction during sauna bathing; patent foramen ovale found
- What
- Sauna bathing (exposure, not intervention)
- Measured
- Ischemic stroke during sauna
- Result
- Single case; authors propose a possible causal link and the term 'sauna stroke syndrome'.
- Limitations
- Single case report; causality uncertain.
Protocols used in the studies
Habitual Finnish sauna use by questionnaire, with the inverse association strongest at 4-7 sessions/week; habitual household hot-tub bathing in Japan (water temperature not reported). No interventional protocol has been tested in stroke patients.
What is still unknown
Whether sauna or bathing affects recurrence after stroke or TIA; safety in patients with post-stroke disability, PFO or on anticoagulation; whether cohort associations are causal.
Safety
Cautions for sauna in this condition
- Case report of large cerebral infarction during sauna in a man with a patent foramen ovale (PMID 17904014).
- Sauna causes acute BP falls and heart-rate rises (PMID 29269746, PMID 32615263); patients with residual deficits, orthostatic hypotension or impaired balance may be at risk of falls or syncope on exiting.
- Alcohol is common in sauna deaths (PMID 18471223).
For clinicians
Suggested rationale
Frequent sauna use (Kunutsor 2018, HR 0.38 for 4-7 vs 1 session/week) and frequent hot-tub bathing (Ukai 2020, HR 0.74) were associated with a lower risk of first stroke in prospective cohorts of stroke-free adults; there is no trial evidence for heat exposure as secondary prevention after stroke, so any recommendation for a stroke survivor is extrapolated.
Suggested wording only. The treating clinician decides whether it reflects their clinical judgment for this patient.
Typical ICD-10 codes: I63.9, I69.30, Z86.73. Examples only; the clinician assigns the code.
What a letter of medical necessity should containWho can write it: physicians, NPs, PAs and others