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Population study: followed a group

Study of 2315 Finnish men: frequent sauna went with lower sudden cardiac death risk

Laukkanen and colleagues · JAMA internal medicine · 2015

Original title: Association between sauna bathing and fatal cardiovascular and all-cause mortality events.

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What the study found

Points to benefit

Compared with 1 sauna a week, the hazard ratio of sudden cardiac death was 0.78 (95% CI, 0.57-1.07) for 2 to 3 and 0.37 (95% CI, 0.18-0.75) for 4 to 7 sessions per week. Similar links for heart disease and all-cause death.

The study at a glance

Type of study
Population study: followed a group
Who or what was studied
2,315 people · middle-aged men from Eastern Finland aged 42-60
What was tested
How often men took saunas (1, 2-3, or 4-7 times a week) and how long, followed for about 20.7 years
What it measured
The question itself: heart disease, blood pressure and death
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
JAMA internal medicine, 2015
Source
PubMed record 25705824. This page is based on the abstract only.

How much this study counts

  • –Shows a link, not a cause: people chose their own habits, and other differences between them may explain the result.
  • ✓Followed people over time, so habits were recorded before the outcome happened.
  • •2,315 people.
  • ✓Measured the question itself: heart disease, blood pressure and death.
  • •The PubMed record has no conflict-of-interest statement.
  • •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

Each dot is one on-topic paper on this question. Steps near the top answer the question more directly.

↑ 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

    ↑ This study is the ringed dot

  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

Of the other 3 papers on the same step: 3 benefit. This one found benefit. It agrees with most of them.

  • Quoted in “What we found”: Among 2315 Finnish men tracked 20.7 years, those taking saunas 4 to 7 times weekly, versus once, had under half the risk of sudden heart death (hazard ratio 0.37).
  • Part of the finding “Finnish cohort links frequent sauna to fewer deaths”.
  • Marked as a key paper in the research timeline: Finnish cohort links frequent sauna to fewer heart deaths.
  • Open item for a person: One Finnish Kuopio cohort: Laukkanen 2015, Zaccardi 2017, Kunutsor 2022, Kunutsor 2024 (plus off-topic 27932366, 29720543). Counted once as evidence.

Other papers on the same step

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
Source check by a person
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