Yes, it is a major risk factor for heart disease. Single BP readings are never diagnostic though. If you have a few high readings, your GP will want to do a 24 hour blood pressure study to get a more accurate analysis of your blood pressure. If your BP is consistently above 150, then this is within treatment range. The treatment threshold is lower if you have risk factors such as diabetes etc. If you are fairly young, your GP will want to rule out secondary problems such as hormone or kidney issues. If your blood pressure is this high, it is dangerous because your heart is being forced to work way beyond it s capacity. Besides injuring blood vessels, it can damage the brain, cause swelling of the optic nerve or hemorrhaging of the retina and kidneys issues. You are also at an increased risk of suffering from a cardiovascular event such as stroke and/or heart attack. Has your GP checked your cholesterol levels? In the meantime, reduce sodium in your diet, exercise and lose weight if you are overweight. Optimal BP is 120/80, regardless of adult age.