The relationship between sauna use and cardiovascular health is one of the most discussed health benefits. Overseas studies have reported that people who use saunas more often tend to have a lower risk of death from cardiovascular disease.

But to be clear at the outset, this does not mean that saunas cure or prevent heart disease. What the research shows is a correlation, not causation. In this article, we will break down the commonly cited studies, possible mechanisms, and the precautions people with chronic conditions should take, from a safety-first perspective.

What research has found

The most frequently cited study is a large Finnish cohort study, the Kuopio Ischemic Heart Disease Risk Factor Study. It followed 2,315 middle-aged men for a median of about 20.7 years and found that more frequent sauna use was associated with a lower risk of sudden cardiac death and cardiovascular mortality.

The numbers alone make the association look strong. However, this is an observational study and does not directly prove causation. Exercise habits, diet, sleep, income, and other factors among frequent sauna users may also have influenced the results. The participants were middle-aged Finnish men, so the findings cannot be applied to everyone as-is. That is why saunas should not be treated like medicine.

Possible mechanisms

When you enter a sauna, your body temperature rises, blood vessels in the skin expand, and your heart rate increases. In healthy people, this temporary change is thought to work as a stimulus similar to light exercise.

In addition, relaxation may reduce stress, improve sleep quality, and temporarily lower blood pressure, which may connect to long-term lifestyle benefits. However, these are the result of multiple factors combined, so it is better not to oversimplify them as a sauna-only effect.

Effects on blood pressure

After a sauna session, blood vessels widen, so blood pressure tends to drop. This is why some people feel lightheaded after bathing. On the other hand, some reports suggest that blood pressure may stay lower over the long term.

However, whether sauna use is safe for people with hypertension depends on the severity of the condition and medication status. Rather than using saunas instead of blood pressure management, the realistic approach is to continue medical care while using saunas within a comfortable range.

A cold plunge bath is not required

In Japan, it is common to enter a cold plunge bath after a sauna, but from a cardiovascular perspective, a cold plunge bath is not essential for everyone. Sudden temperature changes can feel refreshing for some people, but stressful for others.

Especially for older adults or people with chronic conditions, it may be safer to cool down with a lukewarm shower or a rest break rather than jumping directly from a hot sauna into a cold bath. Even if studies show an association with sauna use, there is no need to force yourself to recreate the cold plunge experience.

People who should be cautious

The following people should think carefully before using a sauna.

• Those with heart conditions such as heart failure, arrhythmia, angina, or after a heart attack
• Those with severe hypertension or unstable blood pressure
• Those prone to dehydration or with unstable health
• Those using a sauna after drinking alcohol or for long sessions like a test of endurance

This article provides general information and is not medical advice. If you have a chronic condition or symptoms that worry you, do not rely on saunas on your own. Please consult a medical institution for advice and evaluation.

For overall health management, precautions before entering an onsen may also be helpful.

Safety guidelines for use

Even if you want to use saunas for their potential benefits, there is no need to aim for high heat, long sessions, or frequent use. It is safer and easier to maintain if you keep sessions short on days when you feel well, drink enough water, and take breaks.

Useful signs are not feeling dizzy after the sauna, having no palpitations or chest pain, and not being left with strong fatigue the next day. Using saunas within a range you can continue comfortably is, in the end, the most realistic approach. The broader effects and limits of saunas are also covered in Sauna Health Benefits.

Frequently asked questions

Are saunas good for the heart?

Some studies have shown that people who use saunas more often tend to have a lower cardiovascular risk, but this does not prove causation. Saunas are not a substitute for treatment or prevention. Think of them as something healthy people can enjoy within a reasonable range.

Can people with high blood pressure use a sauna?

It depends on the severity of the condition and medication status. Do not judge for yourself. Consult your doctor first, and start with short sessions and lower temperatures.

Is there no benefit unless you use a cold plunge bath?

Not at all. A cold plunge bath is not essential. If it does not suit you, resting or using a lukewarm shower is enough.

How often should I use a sauna?

Research shows an association with frequency, but this is not a contest for the number of sessions. The basic rule is to use it without overdoing it on days when you feel well.

Summary

Regarding saunas and cardiovascular health, observational studies have found that more frequent use is associated with lower risk. However, this does not prove causation, and saunas should not replace treatment or prevention. In practice, keep sessions short and comfortable, and make sure to rest and hydrate. If you have a chronic condition, consult a doctor first and enjoy saunas only within a safe range.

Sources

• Laukkanen T, et al. "Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events" JAMA Internal Medicine, 2015
• Same paper (PubMed)