What is Blood Pressure and Hypertension

The blood pressure measurement is one of the most important measurements taken when you visit your physician.   Hypertension is the term given to the condition of high blood pressure.  Blood pressure is necessary to deliver blood to vital organs.  It is generated by the contraction of your heart in conjunction with the elastic properties of the arteries.  Blood pressure readings are usually recorded as two numbers (systolic BP/diastolic BP) the systolic blood pressure (the top number)is the blood pressure generated as the heart beats and the diastolic blood pressure (the bottom number) is the blood pressure generated while the heart is at rest between beats.  High blood pressure means that your blood is moving through your circulatory system with a pressure higher than normal. The higher the pressure inside your arteries, the higher your blood pressure numbers may be.  When your cardiovascular system (heart and arteries) are healthy, blood flows easily and your heart doesn’t have to work too hard. But when your arteries are too narrow or stiff, blood pressure rises, the heart gets overworked, and arteries can become damaged.  Furthermore, high blood pressure may cause damage to your organs such as your brain and kidneys.  Complications of hypertension include:


  • Stress on the large blood vessels such as the aorta which may predispose to aneurysm formation and risk of rupture.
  • Chronic kidney disease
  • Heart attack and heart failure
  • Poor blood supply to the legs
  • Stroke and dementia
  • Problems with your vision

Blood pressure and hypertension is staged by the 7th report of the Joint National Committee Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) as follows:

Stage Diastolic (bottom number) Systolic (top number)
Normal Less than 120 (mm/Hg) and Less than80
Pre-Hypertension 120-139 (mm/Hg) or 80-89
Stage 1 Hypertension 140-159 (mm/Hg) or 90-99
Stage 2 Hypertension 160 or greater (mm/Hg) or 100 or higher


*Adapted from JNC 7

If you have diabetes or chronic kidney disease you will need treatment when your blood pressure is greater than 130/80.  If your primary physician has difficulty controlling your blood pressure, have difficulty tolerating medicines, or have chronic kidney disease or diabetes you may benefit by being evaluated by a specialist in high blood pressure.