Last reviewed 23 October 2026
People have used saunas for centuries to relax, warm up and feel good. Research on their health effects is growing, but much of it comes with caveats. Here’s a plain summary.
What happens in your body
In a hot sauna your skin warms, your blood vessels widen, your heart beats faster and you sweat. Your heart rate can rise to a level similar to light or moderate exercise. Afterwards, most people feel relaxed and many sleep well.
What studies suggest
- Heart and circulation. The best-known research comes from a long-running study of more than 2,000 middle-aged men in eastern Finland. Men who used a sauna more often had lower rates of heart disease and death over around 20 years of follow-up than men who used one less often.
- Relaxation and wellbeing. Many people report feeling calmer and less stressed after a sauna, and social saunas add the benefit of time spent with other people.
- Muscle soreness. Some athletes use sauna and heat for recovery. Evidence here is mixed and studies are small.
What it doesn’t show
Most of this research is observational: it shows that people who use saunas often tend to be healthier, not that the sauna caused it. Frequent sauna users in Finland may differ in many other ways. A sauna is not a treatment for any condition, and it doesn’t replace exercise, medical care or medication.
Sweating also doesn’t “detox” you in any meaningful way. Your liver and kidneys do that job.
Who should check first
Speak to your GP before using a sauna if you:
- are pregnant
- have a heart condition, have had a heart attack, or have high or low blood pressure
- take medication that affects your heart rate, blood pressure or sweating
- have epilepsy or a condition that affects your temperature control
Don’t use a sauna after drinking alcohol or when you’re unwell, and keep children’s sessions short.
The bottom line
For most healthy adults, sauna sessions are safe and enjoyable, and there’s encouraging evidence they’re good for you. Go regularly if you enjoy it, keep sessions sensible, drink water, and get out if you feel unwell.