Saunas have been traditionally used to produce a feeling of relaxation. As your heart rate goes up and your blood vessels dilate, there is an increase in blood flow to the skin. Saunas may also improve blood circulation. 

Using a sauna can leave people feeling invigorated. Since the blood vessels relax and dilate in a sauna, blood flow increases and the experience can help reduce tension in the joints and relieve sore muscles.