Hypertension is a medical condition in which the blood pressure is chronically elevated. Hypertension also called as High Blood Pressure. Blood pressure refers to the pressure that blood applies to the inner walls of the arteries. Hypertension is one of the major causes of death and disability in the world, and it is also the leading cause of heart attacks, strokes and kidney failure. Hypertension is known as "Silent Killer" because it may be present for years with no perceptible symptoms.

Blood pressure readings are measured in millimeters of mercury (mmHg). The normal blood pressure reading is 120 (systolic) over 80 (diastolic) represented as 120/80 mm of Hg. Systolic pressure refers to the pressure in the arteries as the heart contracts (beats) and Diastolic pressure refers the pressure in the arteries as the heart relaxes between beats. If the blood pressure between 120/80 and 139/89 is called pre-hypertension, and a blood pressure of 140/90 or above is considered high.

Hypertension can be classified as either essential (primary) or secondary. Idiopathic hypertension or Primary hypertension is common; about 90-95% of hypertension is essential hypertension. Secondary hypertension indicates that the high blood pressure is a result of organ injury; it leads heart disease, kidney disease or tumors (adrenal adenoma or pheochromocytoma). Severe and immediately life-threatening hypertension is called malignant hypertension and usually requires hospitalization and acute medical care.