Regular heat: a newer review gives a more cautious answer
Twenty randomized trials found no clear overall improvement in most heart-health markers. Whole-body heating showed a possible blood-pressure benefit.
Worth knowing: Published in 2025; the search ended in November 2024. See the older Pizzey review for the earlier evidence.
The short version
A 2025 review brought together 20 randomized trials of repeated heating. Most heart-health markers showed no clear improvement overall, including blood sugar and measures of artery function. The blood-pressure result was more mixed: whole-body heating showed a possible benefit, while local heating did not. Trials lasted two to 15 weeks and used different kinds of heat. This narrows the encouraging picture from older reviews without proving that heat has no benefit.
Keep in mind
The trials mixed sauna, baths, hot yoga and local heating. A subgroup finding is not proof that ordinary sauna prevents heart disease.
What they found
Across 15 trials, systolic blood pressure was 2.46 mmHg lower, with a 95% confidence interval from 5.02 lower to 0.10 higher. The whole-body subgroup showed 4.11 mmHg lower (7.36 to 0.86 lower).
Artery widening showed no clear improvement in three trials: a difference of −0.055 percentage points (−1.11 to 1.00). Most other pooled markers, including fasting glucose and HbA1c, also showed no clear change.
What this means for your practice
A possible blood-pressure benefit remains worth studying. These results do not establish a sauna routine or a replacement for treatment.
Methods and limitations
What the researchers did
Researchers searched three databases through November 4, 2024, selecting adult randomized trials of repeated passive heating with a control group. Twenty trials qualified.
How much can this tell us?
Restricting the review to randomized trials changes the picture from the older review in this library, which also included non-randomized studies. Many trials overlap, so the two reviews are not independent groups of people.
Small samples and varied treatments limit certainty. The pooled estimate and its interval matter more than whether a result just passes a statistical threshold.
What makes it useful
- Randomized comparisons
- Reports uncertainty and differences between heating methods
What limits it
- Small trials
- Mixed heating methods
- Weeks of follow-up, not disease outcomes
Where this study fits
Where this study fits
We score claims, not single studies. This one is part of the evidence for:
Regular heat keeps blood vessels healthy. Not supported
Low certaintyNo effect foundBody signals
Heat helps control blood sugar. Not supported
Low certaintyNo effect foundBody signals
A few weeks of regular heat lowers blood pressure. Some support
Low certaintySmall effectBody signals
Read the original
Hamaya R et al. Non-acute effects of passive heating interventions on cardiometabolic risk and vascular health: systematic review and meta-analysis of randomized controlled trials. Am J Prev Cardiol. 2025;23:101082.
DOI 10.1016/j.ajpc.2025.101082 · PubMed 41049507