How long have you been exercising Jimbo? If you have high blood pressure, then you should probably be working at a moderate intensity until your fitness improves.
Moderate intensity means working at 65% of your maximum capacity, so you should aim to keep your heart rate around 120 beats per minute. It's fine to work at 100%, which would be 184, but only really fit, athletic people, with no heart problems should do this. 216bpm does sound a little too high, considering you also have high blood pressure.
If you are concerned though, you should speak to your doctor.