I am not really able to post a theory on how heart rate is influenced by a plot, but I am quite sure that there is more than being afraid by seeing torture, seeing action or horror. I am currently using this app together with Dr. André Weinreich, Head of Research & Science from emolyzr (DE), a company founded by the Humboldt University, Berlin. He is a psychologist and dedicated researcher of emotions. We run a study on various movies with a set of Apple Watches and Movie Pulse. You can find out more on the research and analysis topic at movie-pulse.com.