Saunas help you relax and increase your sense of well-being, according to Harvard Health Publications. They cause the heart to beat faster and 30% can burn almost as many calories as a 3-mile race.
Extreme temperatures, such as those found in a sauna, can increase your metabolism by 20%. This can allow you to burn 300 calories in a 30-minute sauna session, according to the book "100 Ways to Supercharge Your Metabolism" written by Cynthia Phillips and her colleagues. The metabolism-boost benefit lasts up to three hours afterwards, which can lead to burn even more calories.
Phillips and his colleagues explain that sweating also increases your metabolism. Sitting in the sauna for 30 minutes can produce the same amount of sweat as a 6-mile run. In the sauna, you can lose up to 1 pound through sweat.
Harvard Health Publications reports that saunas have multiple health benefits, including reducing stress and "seems safe for the body," but advises taking certain precautions. Alcohol and medications can weaken your ability to sweat, which can make it very difficult for your body to cool itself down properly. Avoid these if you are going to enter a sauna. Drink two to four glasses of fresh water after your sauna session; avoid it if you are sick. Also, if you do not feel good when you're in the sauna, get out immediately.