Heart rate is often considered as an indicator of arousal changes. We have found in course experiments that in humans by mildly enhancing general arousal the heart heart rate goes up in some test persons and goes down in others. So, if heart rate has a relation to arousal, it may indicate level changes, but there is no linear relation between arousal level and heart rate.

Is there anybody who could confirm my observation in humans, or knows about a publication. I would also be glad to hear about general definitions of arousal as well as critics of the arousal concept