Blood pressure is the pressure that occurs in the blood vessels as the blood is driven from the heart into the body and later back to the heart. High blood pressure makes the heart pump work harder and can be serious if you do not get it treated. The risk of cardiovascular disease and kidney problems in particular increases if you have high blood pressure.
Low blood pressure is in most cases completely harmless and does not require any treatment. Most people who have low blood pressure have no symptoms. If you have a sudden drop in blood pressure, you should sit down or lie down. Sometimes you may need to seek care.