In Scandinavia, saunas have long been used as a way to socialize as well as for their many health benefits. And while they aren’t quite as popular in the U.S., you can still find saunas in many gyms and community centers.

Saunas are a nice way to relax and have a good sweat, but can they really help you lose weight? The short answer is... sort of.

Researchers still have a lot to learn about how the heat from saunas affects the body.

How Saunas Work

When in Finland...
  • The word “sauna” is Finnish.
  • Finland is estimated to have almost three million saunas. That’s enough to accommodate all 5.4 million Finns at the same time.

A sauna is defined as a room that’s heated to temperatures between 150 and 195 degrees Fahrenheit. Finnish-style saunas are considered “dry,” while Turkish style saunas have lots of steam. People typically spend around 15 to 30 minutes in a sauna.

These are the most common types of saunas:

  • Wood burning: Wood-burning stoves are used to heat sauna rocks. Temperatures are high and humidity is low.
  • Electrically heated sauna: An electric heater mounted on the floor or wall is used to heat the room. Temperatures are high and humidity is low.
  • Steam rooms: You might also know these as “Turkish bath houses.” Temperatures are low and humidity is high, at 100 percent.
  • Infrared: Uses light waves to heat your body without warming the room. The benefits are similar to more conventional saunas.

While the temperatures and humidity levels vary, saunas generally work the same when it comes to how your body reacts.

Dangers of Dehydration

Extreme heat makes your body sweat, and when you sweat you lose fluids. When you lose more fluid than what you’re taking in, you can become dehydrated. There is a risk of getting dehydrated from being in a sauna. According to Harvard Medical School, the average person loses about one pint of body fluid during a short time in the sauna. However, if you drink enough water before, during, and after your time in the sauna, you will replace the fluids lost by sweating.

Signs of Dehydration

Severe dehydration is a medical emergency. It’s important to pay attention to your body and drink plenty of fluids if you use a sauna.

Be aware of these signs of mild to moderate dehydration:

  • dryness in the mouth
  • extreme thirst
  • headache
  • feeling dizzy or lightheaded
  • not urinating as frequently as normal

Older adults and people with chronic conditions such as diabetes, kidney disease, and heart failure, or those who are pregnant, are at a higher risk of becoming dehydrated.

Saunas and Heart Health

The high heat levels you experience in a sauna cause your blood vessels to open up and move closer to the skin’s surface. When blood vessels expand, your circulation improves, and your blood pressure gets lower. Some recent studies have found links between regular sauna use and improved heart health.

However, people who have heart issues such as an irregular heartbeat or recent heart attack are usually told to avoid saunas. People with high blood pressure can use saunas, but the American Heart Association (AHA) warns against moving between extreme hot and cold temperatures because it can raise your blood pressure. Also, those on heart medications should check with their healthcare provider before using a sauna.

Can You Sweat Off Weight?

The weight loss that happens in a sauna is water weight, which you put back on once you begin drinking again. The higher temperatures cause your heart rate to increase in a way similar to exercise. But, this increase only causes a slightly higher calorie burn than sitting at rest. The sauna may be able to help you burn some extra calories, but don’t bank on sweat sessions alone to shed pounds. It is not an effective tool for real weight loss.

The Takeaway

Studies from Finland, Japan, and Germany have found health benefits to regular sauna use. For healthy adults, sitting in a sauna at temperatures around 190 F is considered safe. If you’re pregnant or have a chronic health condition, you’ll want to consult your doctor first.