Comment by p1anecrazy

Once in a while as I get sick I have to retrain myself to going to sauna (e.g. taking lowest level, even skipping the Aufguss, German infusion where temperature is raised gradually etc.)

Also IMO your body fat/water/lean muscle ratio may play a role. I once lost 5 kg due to Influenza A and all my sport achievements as well as sauna endurance were gone