Blood pressure is a measure of force that the circulating blood puts on the walls of the arteries. The condition when the force exceeds normal limit, is called hypertension. It can lead to stroke, heart failure and kidney diseases. Two values of blood pressure are measured - the highest when the heart contracts (systolic) and the lowest when the heart is at rest (diastolic).
It is measured in millimetres of mercury (mmHg). A diet rich in fat and salt; use of tobacco and alcohol; and stress are the major triggers for hypertension. Even a slight elevation in pressure can reduce life expectancy. To reduce harm, doctors prescribe a variety of drugs that can be taken either singly or in combination.
These include alpha blockers, which dilate the blood vessels; angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, which protect blood vessels and heart muscles; beta blockers, which decrease the rate of heart beat and blood pressure; and calcium channel blockers, which dilate the blood vessels.