Background: To examine relationships between teachers' experienced classroom demands and autonomic stress reactions, we report the results of a pilot study. Based on an integrative literature review, we identified and described the following situational classroom demands: time and work pressure (including missing rest periods, time pressure, and pressure to get through the subject matter), vocal strain, uncertainty concerning the subject matter, uncertainty concerning didactical decisions, achievement-related diversity in class, lack of social appreciation, disquietude in class, classroom disturbances, behavioral problems of students, insufficient skills and concentration of students, and insufficient motivation of students. Method: These identified categories of teachers' situational classroom demands are the basis for the empirical item identification and selection (Study A). The identified items were used in a single-case, short-term longitudinal study in which we examined relationships between experienced classroom demands and autonomic stress reactions as well as between autonomic stress reactions and affective stress experience via first-order vector autoregressive modeling (Study B). Results: Concerning our hypotheses, we found evidence that some of the experienced classroom demands ("I cannot respond to students' different needs"; "There is disquietude in class") had time-lagged associations with autonomic stress measures. Furthermore, we found that physiological arousal triggers affective stress experience due to a time-lagged effect. Conclusion: The research approach and results of our pilot study can be the basis for further process-oriented research in vocational education and training (VET). From a practical point of view, our results on experienced classroom demands could be used in VET teacher education to prepare student teachers for specific skills to cope with such demands.