The strongest health claim made for saunas is about the heart. It is also the one where a wrong guess costs the most.
This article lays out what the main study found, what it can’t tell you, and who needs a doctor’s sign-off. It sits under our overview of sauna health benefits. This is general information, not medical advice.
Short answer: regular sauna use is associated with fewer fatal heart events in a long Finnish study, but that is a link, not proof. The effect on blood pressure varies from person to person. If you have any heart or blood pressure condition, talk to your doctor before you use one.
What a sauna does to the heart
The heat makes your heart work. Harvard Health says the pulse rate “jumps by 30% or more,” which lets the heart nearly double the blood it pumps each minute.
UCLA Health gives a range: “your heart rate increases and may reach 100-150 beats per minute.” It says the heat also causes blood vessels to open, which increases circulation.
The 20-year study
The study behind most headlines was published in JAMA Internal Medicine in 2015. Researchers followed 2,315 men aged 42 to 60 in eastern Finland for a median of 20.7 years.
They compared men by how often they used a sauna. The baseline group went once a week.
| Sauna sessions per week | Sudden cardiac death | Fatal heart disease | Death from any cause |
|---|---|---|---|
| 1 (baseline) | 1.00 | 1.00 | 1.00 |
| 2 to 3 | 0.78 | 0.77 | 0.76 |
| 4 to 7 | 0.37 | 0.52 | 0.60 |
The figures are hazard ratios after adjusting for other risk factors. A value of 0.60 means a 40% lower rate than the baseline group over the follow-up period.
Session length mattered too. Sessions longer than 19 minutes were tied to a hazard ratio of 0.48 for sudden cardiac death, compared with sessions under 11 minutes.
The authors concluded: “Increased frequency of sauna bathing is associated with a reduced risk” of these outcomes.
What the study can’t tell you
Here’s what the headline version leaves out.
It was observational. Men who sauna daily may differ from others in ways the adjustments missed. The study shows the two things move together, not that one causes the other.
It covered middle-aged Finnish men using traditional Finnish saunas. It says nothing direct about women, other age groups, or infrared cabins.
The 2-to-3 group’s result for sudden cardiac death (0.78) had a confidence interval of 0.57 to 1.07, which crosses 1.00. On that single measure, the middle group’s benefit isn’t statistically certain.
Blood pressure: the sources differ
UCLA Health: “Evidence over the past few decades shows that sauna bathing has an immediate positive effect on blood pressure.” It also reports that 15 minutes of sauna after a workout, three times a week, improved blood pressure more than exercise alone.
Harvard Health is more cautious about a single session: “Blood pressure is unpredictable, rising in some people but falling in others.”
Both can be true. Averages across a group can improve while individuals respond differently. That is my reading, and it is the reason the next section matters.
Who should ask first, and who should stay out
Cleveland Clinic draws the lines.
Avoid the sauna if you have had a recent heart attack or stroke, or if you have been drinking alcohol.
Check with a provider first if you have a heart condition, including “heart failure, or high or low blood pressure.”
UCLA Health adds that sauna use can lower blood pressure, so people with low blood pressure should talk to their physician.
On cooling off, thisisFINLAND warns: “People with heart complaints or high blood pressure should avoid swimming in cold water after leaving the hot room.”
If your doctor says yes
The practical limits are the same in each source: sessions of about 15 to 20 minutes, water before and after, and no alcohol. Cleveland Clinic suggests new users start around 5 minutes.
Most of the research is on traditional saunas at 80 to 100°C. If you want that kind of heat at home, the home sauna buying guide explains what a traditional heater needs from your house. The Almost Heaven Salem ($4,176), for example, needs a 240V, 30-amp circuit for its 6kW heater.
Bottom line: the evidence linking saunas to heart health is encouraging and incomplete. Treat it as a reason to enjoy a sauna if you are cleared to use one, not as a treatment. Your doctor makes that call.
Sources
- Laukkanen T, Khan H, Zaccardi F, Laukkanen JA, “Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events,” JAMA Internal Medicine, 2015;175(4):542-548: jamanetwork.com
- UCLA Health, “Benefits of sauna bathing for heart health,” February 1, 2023: uclahealth.org
- Harvard Health Publishing, “Sauna Health Benefits: Are saunas healthy or harmful?” May 14, 2020 (opening section): health.harvard.edu
- Cleveland Clinic, “Get Your Sweat On: The Benefits of a Sauna,” August 12, 2024: health.clevelandclinic.org
- thisisFINLAND, “Bare facts of the sauna in Finland,” accessed October 12, 2026: finland.fi
- Almost Heaven Salem listing at Select Saunas (price, power), checked October 2026