When you use a sauna, you’re in effect voluntarily subjecting your body to extreme conditions – with a standard sauna temperature between 90°C and 100°C being followed by cooling down, sometimes below 0°C. Whilst in the sauna, the temperature of your skin rises faster and differently to the temperature inside your body, which never actually increases by more than 1-2°C. After around 10 minutes in the sauna, however, the temperature of your skin increases to 40-42°C. In technical jargon, this is known as hyperthermia, and is one of the positive effects of using the sauna. It significantly stimulates and increases the turnover of various substances – your metabolic rate, in other words. Raising your body temperature from 37°C to 38-39°C is like inducing an artificial fever. Unlike your body itself, numerous bacteria and viruses which can make us ill are unable to cope with such high temperatures, which means that using a sauna can be an effective way of combating infections before they attack.