Everyone has got high blood pressure when exercising, getting angry, or having intense fears. This doesn’t mean that everyone is having hypertension. Hypertension is when the blood pressure becomes abnormally high at rest and without any external stimulation.
The real difference is that constant high blood pressure is much more damaging to the arteries than occasional high blood pressure.
Anyway, in common conversational english, we often use high blood pressure as another term for hypertension.