'Historically, saunas have a longstanding tradition of use. They are common to many Eastern European countries, as well as Asia. In some countries, such as Finland, you can find them in nearly every home, where they're used for relaxation, detoxification and more.
Saunas are actually becoming increasingly used by athletes as well, but not only for the post-workout muscle relaxation as you might expect.
According to Rhonda Perciavalle Patrick, Ph.D., increasing your core temperature for short periods, as is done by using a sauna, may offer dramatic improvements to your athletic performance. She calls this concept "hyperthermic conditioning," which emerging research suggests has multiple positive effects on your body, from increased endurance to the growth of new brain cells.'