Sauna and health: what science says

Saunas and health

Many people find the sauna does them good — and large observational studies from Finland suggest that regular sessions go hand in hand with better cardiovascular health. What these studies show, what they don’t, and what to look out for.

What happens in the body

During a sauna session:

• Your skin heats up a lot and your body temperature rises slightly
• Your heart beats faster
• The blood vessels in your skin widen
• You sweat and lose fluid

What studies show

Heart and circulation

The best-known study followed 2,315 men aged 42 to 60 in eastern Finland for around 20 years. Those who used the sauna 4 to 7 times a week had a roughly 63% lower risk of sudden cardiac death than men who went once a week.

Colds

In a small study of 50 people, the group that used the sauna regularly for six months had fewer colds than the comparison group, especially in the last three months. How long and how severe the colds were did not differ. The study is too small to draw firm conclusions.

Relaxation

Many people find the warmth and the rest breaks soothing and relaxing. That’s a good reason for a sauna day. But the sauna is not a treatment: if you have been feeling low for a long time, talk to a professional.

After exercise

Many athletes like to use the sauna after training. That it speeds up muscle recovery, however, is not well established.

The bigger picture

An independent review looked at 40 studies on regular sauna use. Most report benefits, but many are small. The authors’ conclusion: possible benefits, better studies needed (Hussain & Cohen, 2018).

When you should not use the sauna

Better to skip the sauna:

• Acute infections with fever
• Immediately after a heart attack
• Unstable angina pectoris
• Severe cardiac arrhythmias

Check with your doctor first:

• High blood pressure (controlled by medication)
• Pregnancy
• Epilepsy
• Acute inflammation

Tips for healthy sauna use

1. Not hungry, not full — A light meal 1–2 hours beforehand
2. Drink enough — Water or unsweetened tea, especially after the sauna
3. No alcohol — It strains the circulation; in the rare deaths in Finnish saunas, alcohol was involved in half of the cases
4. Start slowly — Beginners start with short sessions
5. Rest sufficiently — The rest period is just as important as the sauna session

How often?

There is no fixed recommendation. In the Finnish studies, men with 4 to 7 sessions a week did best — that’s an association, not a prescription. For most people, once to three times a week is perfectly manageable. What matters more than the number is that you feel good.

Conclusion

For healthy people the sauna is a pleasant ritual, and the evidence is encouraging. It is not a cure, though: the evidence comes mainly from observational studies. Enjoy the sauna as a break — and take questions about your health to your doctor.