what does the bottom number on blood pressure
""" What would cause my bottom number on my blood pressure be very high? """ This causes a rise in the pressure within the arteries that we call the systolic blood pressure. When the heart relaxes, the blood pressure falls, but doesn't go to zero. This lull in the blood pressure is called the diastolic blood pressure. This is the bottom number. In general, we don't like the bottom number to be much above 85. If this number is too high, then the top number is usually high too. If only the bottom number is high, you may need a very low dose of a blood pressure medication. We call this isolated diastolic hypertension. It isn't that common, and usually does not cause any symptoms in people your age.