How Does a Sauna Work?

This article dives into the mechanics of a sauna, what it does to your body, and the health benefits backed by modern science. Whether you're a casual spa-goer or a wellness enthusiast, understanding how a sauna works will help you use it more safely and effectively.

What Is a Sauna?

A sauna is a small heated room or enclosed space designed to induce sweating through elevated temperatures. Saunas are typically kept between 150°F to 195°F (65°C to 90°C), though infrared saunas use lower ambient heat to achieve similar physiological effects.

There are several types of saunas:

Type	Heating Method	Temperature & Humidity Features
Traditional Finnish Sauna	An electric or wood stove heats the air and rocks	High temperature (70–100°C), low humidity, creates a dry heat environment. Water can be poured on rocks to add humidity
Steam Room (Wet Sauna)	A steam generator produces water vapor	Moderate temperature (40–50°C), high humidity; provides a moist heat that helps moisturize the skin
Infrared Sauna	Infrared light directly warms the body	Moderate temperature (40–60°C), low humidity; heats the body directly instead of the air, warms up quickly

How Does a Sauna Work on the Body?

Here's what happens:

 

1. Your Core Temperature Rises

The high heat raises your internal temperature by about 1–3°F, simulating a fever-like state that activates protective bodily functions.

 

2. You Start Sweating

To cool itself, your body produces sweat—up to a pint every 15 minutes. This helps regulate temperature and flushes out trace minerals and water.

 

3. Blood Vessels Dilate

The heat causes vasodilation, increasing blood flow to the skin and extremities. This temporarily lowers blood pressure and improves circulation.

 

4. Your Heart Rate Increases

Similar to moderate exercise, your heart rate may rise to 100–150 bpm, giving the cardiovascular system a mild workout.

 

5. Heat Shock Proteins Are Activated

These cellular protectors are triggered during heat exposure and may help with muscle repair, immune function, and longevity.

How Different Saunas Work

Type	Heat Source	Air Temperature	Humidity	Key Features
Traditional Sauna (Dry Heat)	Electric stove or wood-burning heater	170–195°F (77–90°C)	Low (5–20%); humidity increases if water is poured over rocks	Classic dry heat; intense sweating; traditional sauna experience
Steam Room (Wet Sauna)	Steam generator	110–120°F (43–49°C)	Extremely high (100%)	Feels hotter due to moisture saturation; promotes skin hydration
Infrared Sauna	Infrared panels emit radiant heat	120–140°F (49–60°C)	Low humidity	Heats the body directly; gentler and more tolerable for beginners

 

Health Benefits: What Science Supports

Sauna use is far more than just a luxury. Numerous studies have shown its positive impact on several aspects of health:

 

Cardiovascular Health

A 2015 Finnish study found that regular sauna bathing reduced the risk of fatal heart disease by up to 50% in men. The effect was dose-dependent—the more frequent the use, the greater the benefit.

 

 Muscle Recovery and Pain Relief

Heat helps relax tense muscles, reduce joint stiffness, and improve recovery time after exercise or injury.

Improved Sleep

Post-sauna relaxation and endorphin release can promote deeper, longer sleep.

Mental Health Support

The combination of heat exposure, mindfulness, and solitude can reduce stress, anxiety, and even mild depression.

Potential Immune Support

Mild elevation of body temperature may help the body fight infections, though it should not replace medical care.

How to Use a Sauna Safely

To enjoy the full benefits of a sauna while minimizing risks:

Stay hydrated before and after sessions

Limit time to 15–20 minutes per session

Avoid alcohol and heavy meals beforehand

Cool down gradually afterward—don’t jump into a cold shower immediately

Listen to your body—lightheadedness or nausea are signs to exit

People with heart conditions, low blood pressure, or who are pregnant should consult a doctor before using a sauna.

Conclusion

Knowing how a sauna works turns a simple sweat session into a strategic tool for health and wellness. Whether you're in it for relaxation, recovery, or longevity, respecting the science behind the heat will help you gain more from every session.