Hi Ayna,
Do you have low blood pressure? Sometimes the body notices that your BP is too low, so it automatically raises your heartbeat to increase the BP to a normal rate for you. It is our survival mechanism that everyone has.

If we lose a lot of blood, our BP drops, so our heart rate goes up then too to keep your heart pumping. Again another survival mechanism built into all our bodies.

If you're stressed or anxious, then the heart rate goes up and BP too. That is why a doctor or nurse waits awhile and then takes it again if you are the nervous type.

They used to call that the "White Coat Syndrome." See a doctor's coat and you get nervous or stressed. It happens to people with normal BP and HR too. Being fearful of what the doctor may say does it.

Before you take your pulse (don't use your thumb, it has it's own pulse) use pointer and middle finger, sit and rest for twenty minutes, do not eat or talk, smoke or drink caffeine or alcohol.

Then take it. Take it for one full minute, not 15, or 30 seconds to be sure. It varies in one minute perhaps different from a 30 second count.