The aim of this clinical study is to evaluate the impact of wearing firefighters' personal protective equipment (PPE) on the quality of chest compressions during simulated resuscitation scenarios. The study compares the effects of one-minute versus two-minute intervals for switching the individual performing compressions. How does the clinical trial work? This randomized cross over trial will be conducted in several locations and will involve a total of 38 fire-fighters. The study will be conducted by the Department of Anesthesiology of the Medical University of Vienna. Participation in this clinical study is expected to last 30 minutes in total. Participants are randomized to either one or two minute intervalls of performing chest compressions in teams of two. After a cooling-of phase of at least 24 hours, they will be switched to the other group. Chest compressions will be performed for 12 minutes in full firefighter's PPE. Primary outcome will be chest compression depth.