You may have seen or heard of health clubs or gyms having saunas in the locker room for relaxation after a sweat session. But are they really good for your health?

Saunas can have benefits, but only if used correctly. Read on to learn more about how saunas work and how they can potentially help your health.

There are a few different types of saunas, but in general all saunas are rooms that are heated to temperatures between 150°F and 195°F (65°C to 90°C).

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, depending on how much heat they can tolerate.

The differences in saunas are in the methods used to produce heat. These are the most common types:

  • Wood burning: Wood-burning stoves are used to heat sauna rocks. Temperatures are high, but humidity is low.
  • Electrically heated sauna: An electric heater fixed to the floor or wall is used to heat the room. Temperatures are high, but humidity is low.
  • Steam rooms: These are also called “Turkish bath houses.” Temperatures are low and humidity is high, at 100 percent.
  • Infrared: Light waves from specialized lamps are used to heat your body without warming the room. The benefits are similar to more conventional saunas, but at much lower temperatures. Infrared saunas are usually around 140°F (60°C).

While the temperatures and humidity levels vary, the effect on the body is similar for all types of saunas.

In addition to being a relaxing way to end a workout, saunas do have some health benefits.

Spending time in the sauna might have a positive effect on heart health. Some research has shown that the high temperature exposure helps blood vessels expand, which helps improve circulation and lowers blood pressure.

“There are people who have chronic muscle and joint pain from rheumatoid arthritis and fibromyalgia, etc. [Studies have] shown that saunas can help with pain and fatigue associated with those conditions,” says Dr. Ai Mukai, physical medicine and rehab specialist at Texas Orthopedics.

Dr. Mukai also says that some athletes use saunas to help with performance and endurance. “Muscle strength and power seem to increase after sauna use. If you’re looking to build strength and power, saunas can help with that.”

The weight you lose from being in a sauna is water weight, which is not ideal. Being chronically dehydrated is not a good state for the body, so you want to make sure to replace this lost water weight as soon as possible. But being in the high heat does cause your heart rate to go up slightly, which may make you able to burn more calories sitting in a sauna than you would sitting at rest in normal temperatures. However, this effect is very small and will likely not have a great overall impact on total calories burned.

Dr. Mukai stresses balance when it comes to weight loss programs. Sauna use alone won’t help you lose weight, but it might be helpful when used as part of a healthy weight loss plan. “Overall, if you’re on a program where you’re working on both diet and exercise, the sauna can be a beneficial component to a holistic plan.”

All saunas expose your body to warm temperatures. When your body gets overheated, you sweat. Sweating causes you to lose fluids. You get dehydrated when you lose more fluid than you’re taking in. There’s a risk of getting dehydrated from being in any type of sauna.

When you factor in that you’ve already been sweating during a workout, you need to be especially careful.

“The biggest risk (of sauna use) is dehydration,” says Dr. Mukai. “Drink plenty of fluids. If you’re going to be sweating a lot, look into electrolyte drinks.”

According to Harvard Health Publications, the average person loses about a pint of sweat during a short time in the sauna. But you can prevent dehydration by drinking enough water before, during, and after your time in the sauna. This will help replace the fluids your body will lose while sweating.

Severe dehydration is a health emergency and needs medical attention.

To avoid dehydration, drink plenty of fluids and know these signs of mild to moderate dehydration:

  • dryness in the mouth
  • extreme thirst
  • headache
  • feeling dizzy
  • feeling lightheaded
  • not urinating as frequently or having very concentrated urine

Older adults and people with chronic conditions such as diabetes, kidney disease, and heart failure are at a higher risk of becoming dehydrated. If you have an existing health condition, check with your doctor before using any type of sauna. Also, be sure to check with your doctor before using a sauna if you are pregnant, as it may not be recommended.

Using the sauna after a workout can be helpful if it’s done carefully and responsibly. According to Dr. Mukai, you should ease yourself into sauna use. “I usually tell people to start with a shorter time and see how they feel right after, and then for the rest of the day.” Try starting with only five minutes. Build up if you feel comfortable.