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Trial, not randomized · measured the question itself

5-year trial in 129 people with severe heart failure: fewer heart events with sauna

Kihara and colleagues · Journal of cardiology · 2009

Original title: Waon therapy improves the prognosis of patients with chronic heart failure.

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

Heart failure events or heart death happened in 68.7% of the control group but only 31.3% of the sauna group (P<0.01) at 60 months. 12 control and 8 sauna patients died.

The study at a glance

Type of study
Trial, not randomized
Who or what was studied
129 people · people with severe chronic heart failure
What was tested
Far infrared dry sauna at 60 degrees C for 15 min, daily for 5 days then at least twice a week, vs usual heart failure care, followed 5 years
What it measured
The question itself: heart disease, blood pressure and death
How long
260 weeks
Who has a stake
No disclosure in PubMed
No disclosure in PubMed.
Journal
Journal of cardiology, 2009
Source
PubMed record 19304125. This page is based on the abstract only.

How much this study counts

  • –Not randomized: the groups may differ in ways that affect the result.
  • •Medium size: 129 people.
  • ✓Long: about 5 years.
  • ✓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

    ↑ This study is the ringed dot

  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

Of the other 2 papers on the same step: 2 benefit. This one found benefit. It agrees with most of them.

  • Part of the finding “One small study tracked heart failure events”.
  • Marked as a key paper in the research timeline: Five-year follow-up: fewer heart failure events with Waon.
  • Open item for a person: Ye 2020 reports 31.3% fewer heart deaths and rehospitalizations in 65 patients; this may be Kihara 2009's data. Check before counting separately.
  • Open item for a person: Kihara 2009, Kuwahata 2011 and Fujita 2011 cite the authors' own earlier Waon work; check for shared patients and device ties.
  • Open item for a person: Kihara 2009 is a matched, non-randomized comparison; Miyata 2008 calls itself case-control but says patients were randomized.

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 differed. The reviewer checked the abstract and kept the first read. 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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