Is the sauna healthy? For healthy adults, sauna bathing in moderation is considered harmless and possibly beneficial to health – this is how Barmer, for example, sums it up. The full answer is somewhat more nuanced: many of the frequently cited results come from observational studies with Finnish men, and for some people the sauna is not suitable.

This article puts into perspective what research actually shows about the effects of the sauna, where its limits lie and who should seek medical advice before a sauna session.

Important note: This article provides general information and does not replace medical advice. If you have pre-existing conditions or take medication regularly, please clarify your sauna visit in advance with your doctor.

Photo: Wellnesshotel Sonnenhof & Sonnhalde

Is the sauna healthy? What happens in the body

During a sauna session, body temperature rises by about 1 °C, according to Barmer. The heart rate increases to around 120 to 150 beats per minute; at rest it is 60 to 80 in healthy people. Blood pressure initially rises, and the blood vessels widen.

According to Barmer, the strain on the circulation is similar to a short, moderate workout; Apotheken Umschau compares it to climbing stairs. After the sauna session, temperature and pulse return to normal, and according to Barmer blood pressure even drops below its starting level.

What studies show about the effects of the sauna

Heart, circulation and more: the Finnish long-term studies

The best-known study was carried out by Laukkanen and colleagues (JAMA Internal Medicine, 2015). It followed 2,315 men from eastern Finland, aged 42 to 60, for an average of 20.7 years. Those who went to the sauna four to seven times a week had a clearly lower risk of sudden cardiac death than men who went once a week (hazard ratio 0.37). With two to three sauna sessions a week, the difference was not statistically clear.

The same research group has published further analyses. The overview below compares “four to seven sauna sessions a week” with “one sauna session a week” in each case. A hazard ratio below 1 means that an event occurred less often in the group that used the sauna frequently.

Outcome studied	Study and participants	Hazard ratio (4–7 vs 1 per week)
Sudden cardiac death	JAMA Internal Medicine 2015; 2,315 men, 20.7 years	0,37
Death from cardiovascular disease	BMC Medicine 2018; 1,688 men and women, 15 years	0,23
High blood pressure (new cases)	American Journal of Hypertension 2017; 1,621 men, 24.7 years	0,54
Stroke	Neurology 2018; 1,628 men and women, 14.9 years	0,39
Dementia	Age and Ageing 2017; 2,315 men, 20.7 years	0,34
Respiratory diseases (asthma, COPD, pneumonia)	European Journal of Epidemiology 2017; 1,935 men, 25.6 years	0.59 (at least 4 vs at most 1)

The ranges of uncertainty for these values are in some cases wide; you will find the exact figures in the linked studies at the end of the article.

How reliable are these results?

All the studies mentioned are observational studies. They show an association, but not proof of cause and effect. In a commentary on the 2015 study, the physician Rita Redberg (UCSF) pointed out that people who go to the sauna often may simply lead more relaxed or more socially active lives (Deutsches Ärzteblatt). In addition, most of the long-term data come from Finland and mainly concern men; according to Apotheken Umschau, they cannot simply be applied to other countries.

A systematic review by Hussain and Cohen (2018) evaluated 40 clinical studies with a total of 3,855 participants. Only 13 of them were randomised controlled trials, and most were small. The authors’ conclusion: regular sauna bathing has potential health benefits, but more and better data are needed. Prof. Axel Schmermund, a cardiologist, says in Barmer that frequent sauna sessions are not harmful for healthy people according to current knowledge.

What is the sauna good for? Possible benefits at a glance

Circulation and blood pressure: Observational studies see an association with fewer cardiovascular diseases (see table). Experts cite less stiff arteries and better function of the inner lining of the blood vessels as possible mechanisms.
Airways and infections: A small study with 25 volunteers in each group found fewer colds over six months among regular sauna users; the authors wrote that the sauna “probably” reduces the number of colds and that further studies are needed. You can read more in the article Sauna during a cold.
Muscles and joints: A review article (Hannuksela and Ellahham, 2001) cites relief of pain and better mobility in rheumatic conditions as a possible effect; Barmer also mentions tension headaches as a possible area of use.
Relaxation: Barmer cites reduced stress as a possible effect; however, the research on stress reduction is less extensive than that on the heart and circulation.

Detox and weight loss: what the sauna does not do

According to Barmer, the claim that the sauna “detoxifies” the body is not sufficiently proven. Apotheken Umschau explicitly rejects the myth of “purging”: sweat contains no more toxins than other body fluids.

According to Barmer, weight loss after a sauna session is also purely a loss of fluid, which you make up for by drinking. The sauna is therefore not suitable for losing weight.

Risks and drawbacks of the sauna

Circulation: If you get up too quickly, you may feel dizzy because the blood “pools” in your legs (SRF). Barmer advises sitting up during the last two minutes.
Alcohol: According to the review by Hannuksela and Ellahham, it increases the risk of a drop in blood pressure, cardiac arrhythmias and sudden death. Apotheken Umschau reports that alcohol was almost always involved in avoidable deaths in Finnish saunas.
Overheating: Older people in particular should not stay in the heat for too long. If you feel unwell or dizzy, leave the cabin immediately, even during an Aufguss (apotheken.de; more in the article Sauna infusion).
Insulin: Heat speeds up the absorption of insulin into the blood; without an adjusted therapy there is a risk of hypoglycaemia (Apotheken Umschau).
Fertility: In a very small study of ten men, sperm production was impaired and recovered after the sauna sessions ended (Hussain and Cohen). The data are thin.

When to avoid the sauna or ask first

Health insurers and specialist literature name these contraindications. The list is not exhaustive; if in doubt, your doctor will decide.

Acute infections, fever, acute inflammation: Here you should refrain from using the sauna (Barmer, TK). Details in the article Sauna during a cold.
Low blood pressure: The sauna lowers blood pressure further, and there is a risk of fainting (Barmer).
Acute heart conditions: recurring chest tightness or unstable coronary heart disease, recent heart attack, uncontrolled high blood pressure, unstable heart failure, severe narrowing of the aortic valve (Barmer; similarly Hannuksela and Ellahham). With stable angina pectoris or a heart attack that occurred a long time ago, the sauna is, according to this review, safe for most people – but only after consulting a doctor.
High blood pressure and other heart conditions: Do not underestimate the strain, and speak to your doctor beforehand (Apotheken Umschau). After a heart attack, the AOK (referring to the Deutsche Herzstiftung) advises avoiding cold plunges and sudden cooling.
Insulin-dependent diabetes: Agree your therapy with your doctor beforehand.
Pregnancy: discuss it with your gynaecologist beforehand (Barmer).
Uncertainty or starting late in life: The Deutscher Sauna-Bund recommends that beginners with health problems consult a doctor experienced in sauna use before their first sauna bath.

You can read how long a sauna session should last and how to cool down properly in the article Sauna rules for beginners. The studies above compare frequencies, but they do not give a medical recommendation on how often you should use the sauna.

Sauna at the Wellnesshotel Sonnenhof & Sonnhalde

With us in Ühlingen-Birkendorf, at 800 metres above sea level, the spa area is open daily from 9:00 to 20:00. You can choose between the panoramic sauna with forest views (Finnish sauna, 12:00 to 20:00), the garden sauna (swimwear allowed) (14:00 to 20:00) and the herbal steam sauna (bio sauna) (16:00 to 20:00). The sauna is open to guests aged 16 and over.

For resting between sessions, there are the relaxation rooms “Garden” and “Waldblick”, a Kneipp water-treading pool and two wellness tea stations. You will find an overview in our article on the Sauna landscape in the Black Forest. The articles explain how the saunas differ Finnish sauna and Steam bath or sauna.

Photo: Wellnesshotel Sonnenhof & Sonnhalde

Day guests are also welcome: the Day Spa starts with “Schwarzwald Light” (admission and wellness bag) from €29.90 (as of October 2026). For a longer stay, you will find our packages under Booking.

Frequently asked questions

Is the sauna healthy for everyone?

No. For healthy adults, sauna bathing in moderation is considered harmless, but the sauna is not suitable in the case of acute infections, fever, low blood pressure or certain heart conditions. If in doubt, ask your doctor beforehand.

How often should you go to the sauna?

The sources used here give no generally valid medical recommendation. The Finnish studies compared one, two to three, and four to seven sauna sessions a week. Go by how you feel, and if you have existing conditions, discuss frequency and duration with your doctor.

Does the sauna detoxify the body?

That is not sufficiently proven. Barmer and Apotheken Umschau reject the detox claim; the weight lost through sweating is fluid loss.

Can I use the sauna if I have high blood pressure?

With uncontrolled high blood pressure, the sauna is considered unsuitable (Barmer). If your high blood pressure is being treated, you should not underestimate the strain and should seek medical advice beforehand (Apotheken Umschau).

Is the sauna allowed during pregnancy?

You should discuss this with your gynaecologist beforehand (Barmer).

Is the sauna healthy? Effects, benefits and when you should avoid it

Is the sauna healthy? What happens in the body

What studies show about the effects of the sauna