1. What causes hypertension?
While the causes of
hypertension in most people remain unclear, a variety of conditions
and states--such as getting little or no exercise, poor diet,
obesity, older age, and genetics--can lead to
hypertension.
2. How is blood pressure measured?
Your doctor or
health care provider can check your blood pressure during a
physical exam. (You can also check your own blood pressure at
home.) Blood pressure is measured with a device known as a
sphygmomanometer, which consists of a stethoscope, arm cuff, dial,
pump, and valve. (A digital blood pressure monitor provides an
electronic blood pressure reading.) The blood pressure reading is
measured in millimeters of mercury (mm Hg), and is written as
systolic pressure (the higher pressure when the heart is
contracting) over diastolic pressure (the lower pressure when the
heart is relaxed), for example, 120/80 mm Hg, or "120 over 80".
3. What is a normal blood pressure?
The Joint
National Committee on Prevention, Detection, Evaluation, and
Treatment of High Blood Pressure has classified blood pressure
measurements into several categories:
- "Normal" blood pressure: less than 120/80 mmHg
- "Pre-hypertension": 120-139/80-89 mmHg
- Hypertension: greater than 140/90 mmHg
4. What health problems are associated with
hypertension?
Several potentially serious health
conditions are linked to hypertension:
- Atherosclerosis is a disease of the arteries caused by a
buildup of plaque, or fatty material, on the inside walls of the
blood vessels. Hypertension contributes to this buildup by putting
added stress and force on the artery walls.
- Heart disease includes heart failure (the heart
can't adequately pump blood), ischemic heart disease (the
heart tissue doesn't get enough blood), and hypertensive
hypertrophic cardiomyopathy (enlarged heart).
- In kidney disease, hypertension damages the blood
vessels and filters in the kidneys, so that the kidneys cannot
excrete waste products.
- Hypertension can lead to stroke, either by contributing
to the process of atherosclerosis (which can lead to blockages
and/or clots) or by weakening the blood vessel wall and causing it
to balloon and burst.
- Eye disease can occur because hypertension damages the
very small blood vessels in the retina.
5. How do I know if I have hypertension?
Hypertension doesn't have any symptoms, so you usually
don't feel it. For that reason, hypertension must be
diagnosed by a health care professional. This is especially
important if you have a close relative who has hypertension.