Heart rate refers to the number of times that the heart muscle contracts or beats averaged for a specific period of time, usually 1 minute. Hence, many heart rate studies use the standard measure of beats per minutes (BPM). Heart rate, along with blood pressure, falls within the general class of hemodynamic variables that measure moment-by-moment changes in vascular activity produced by the autonomic nervous system under conditions of physical exertion, psychological stress, or when symptoms of certain disease processes are present.

Heart rate is pertinent to the study of human communication for at least two reasons. First, in some cases, study participants may give false or misleading information during structured interviews and even when completing anonymous surveys. Some survey respondents suppress or underreport upsetting memories, ...