Autonomous driving is getting more common and easily accessible with rapid improvements in technology. Prospective buyers of autonomous vehicles need to adapt to this technology equally rapidly to feel comfortable in them. However, this is not always the case, since taking away control from the user often correlates with loss of comfort. Detecting uncomfortable and stressful situations while driving could improve driving quality and overall acceptance of autonomous vehicles through adaption of driving style, interface and other methods. In this paper, we test a range of methods, which measure the discomfort of a user of an autonomous vehicle in real-time. We propose a portable set of sensors that measure heart rate, skin conductance, sitting position, g-forces and subjective discomfort. Preliminary results will be examined and next steps will be discussed.