Clambering into a hot sauna might be the last thing you want to do during a heatwave. But researchers say that 'heat training' in these roasting hot Scandinavian baths could be critical in helping us adjust to the scorching summer temperatures. According to Professor Laukkanen, heat training is best done in a slow and steady process over a longer period of time. Heat training typically takes about 40 to 60 minutes of heat exposure each day for four to six days, with benefits that last for around a week. However, longer–term benefits are possible with longer periods of heat training.