@Feryll - High pulse rates and other changes in the body are common when we get nervous, excited or angry. As this article says, when your pulse rate stays high for long periods that's when you should become concerned, and get to a doctor.
Every time I go to a doctor, my blood pressure goes through the roof and my hear rate increases. I get anxious when they start taking my readings because I know the numbers are going to be high, and this makes the readings go even higher.
This isn't a problem now that I have a regular doctor who knows my situation, but when you go to a doctor or dentist for the first time and try to explain what is happening, they think you are just making an excuse because you don't want to be seen as unhealthy or don't want to accept reality.
I have a machine at home that measures blood pressure and pulse rate, so I use that before I go to the doctor and then I let him know how my readings have been the previous week.