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Opinion or narrative review

Review of 45 bath and sauna studies: sauna linked to lower heart disease, death

Nagai and colleagues · International journal of environmental research and public health · 2026

Original title: Effects of Bathtub Bathing and Sauna Practices on Cardiovascular and Systemic Health: A Narrative Review.

Under review. A person has not yet checked this summary against the paper. It is written from the PubMed abstract. Until a person checks it, search engines are asked not to list this page.

What the study found

Points to benefit

Sauna bathing, studied mostly in Finnish cohorts, was linked to lower heart disease and all-cause death, and better inflammation and artery-lining markers. Bathtub evidence was limited to observational studies of markers. The authors call for studies with clear clinical endpoints.

The study at a glance

Type of study
Opinion or narrative review
Who or what was studied
adults in studies of hot bathtub bathing or sauna
What was tested
Review of studies on habitual bathtub bathing (17 studies) and sauna use (28 studies)
Who has a stake
No stake declared
No competing interests declared.
Journal
International journal of environmental research and public health, 2026
Source
PubMed record 41899724. This page is based on the abstract only.

How much this study counts

  • –An opinion or narrative review: no new data, and no set method for choosing which studies to discuss.
  • ✓No competing interests declared.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

This paper is not on the ladder. It is a opinion or narrative review, and reviews and opinion pieces discuss studies that are already counted on the steps below.

↑ Stronger evidence

  1. Trials in people: heart disease, blood pressure and death

    3

    3 benefit

  2. Trials in people: other measures

    2

    1 benefit, 1 no difference

  3. Trials in people: lab tests or safety

    5

    2 benefit, 1 mixed, 2 no difference

  4. Population studies

    4

    4 benefit

  5. Blood levels and genes

    0

    None among the papers we read.

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Does sauna use lower heart disease risk?”

Possibly, but not proven in trials.

Confidence: low. Based on 21 on-topic papers.

Read the full answer
  • Listed with the other papers, but not quoted in the page’s main findings.

Other opinion on this question

See all 21 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The two reads agreed on every checked field. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
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