A sauna is a small room or building that is made hot. The heat of a sauna is calming and makes the person using it sweat. This is believed to help people be more healthy though it causes stress on the body by overheating. Today many countries and groups of people have different ways of heating and using a sauna. The temperature is often 80°C in Finnish saunas. The heat can be more than 100°C. Finnish and Swedish saunas have lower humidity (the air is less wet) to make this high heat comfortable.