Hypertension: High blood pressure, defined as a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 or a diastolic pressure above 90.
Chronic hypertension is a "silent" condition. Stealthy as a cat, it can cause blood vessel changes in the back of the eye (retina), abnormal thickening of the heart muscle, kidney failure, and brain damage.
For diagnosis, there is no substitute for measurement of blood pressure. Not having your blood pressure checked (or checking it yourself) is an invitation to hypertension.
No specific cause for hypertension is found in 95% of cases.
Hypertension is treated with regular aerobic exercise, weight reduction (if overweight), salt restriction, and medications.