What is High Blood Pressure?

Hypertension is high blood pressure, and it is a major risk factor for heart attack and stroke, which constitute the major causes of death in Australia. Globally, hypertension is of major health importance and by the year 2025, hypertension is expected to increase by 60%, affecting 1.6 billion people. The danger of hypertension is that it is often without symptoms. It is a tragedy when the first sign of high blood pressure is a stroke that leaves the victim permanently disabled.

Yet hypertension is preventable, easily detected and treatable. That is why the High Blood Pressure Research Council of Australia recommends that you should “know your blood pressure”.

On average, blood pressure is higher in men than women and so hypertension is also more frequent in men. Age is another reason why blood pressure rises, particularly in Western cultures where it is probably related to lifestyle and the middle age spread.

In most cases medical tests fail to reveal a specific cause of hypertension, although a family history of high blood pressure is often present. This reflects than fact that genes and family environment play a role. In a minority of hypertensive individuals a cause will be clearly identified such as kidney trouble or hormonal imbalances. Although uncommon, these conditions can be reversed by appropriate treatment and blood pressure can be  “cured”.

For the rest, treatment of hypertension either with lifestyle modification or with drugs reduces the risk of heart attack, stroke and death.


Blood pressure is normally measured in the doctor’s office using a sphygmomanometer. The technique involves wrapping an inflatable cuff around the upper arm. The cuff is inflated until blood flow in the arteries of the arm is stopped. The cuff is slowly deflated and a stethoscope is used to hear sounds coinciding with the heartbeat.

The pressure at which sounds start is the systolic pressure. This is the maximum pressure developed by the beating heart. The lowest pressure between heartbeats is also recorded when sounds disappear. This is the diastolic blood pressure. Pressures are usually recorded in millimeters of mercury (mmHg) and cited as systolic over diastolic pressure, for example, 120/80 mmHg. Resting blood pressure below 140/90 mmHg is generally considered normal.

Blood pressure is however very variable and can be elevated transiently by stress, emotional state, recent physical activity, smoking, caffeine and even talking. Hypertension is not therefore diagnosed until resting blood pressure is shown to be consistently elevated during several successive visits to your doctor. Sometimes blood pressures can be measured by automated machines at home, but it is important to use reliable and validated equipment. More comprehensive measures of blood pressure can be made using ambulatory monitors that are fitted to patients for a 24-hour period. These readings give a measure of blood pressure during normal daily activities and can be helpful in determining the diagnosis of hypertension in certain cases in which clinic measures are inconclusive.


The usual starting point is to ensure that a healthy lifestyle is followed. Lifestyle factors that reduce blood pressure include weight reduction (average 1 mmHg per kg lost), regular aerobic exercise, low salt diet and alcohol restriction. If drug treatment is deemed necessary, doctors and patients have a wide range of useful drugs from which to choose.

The names of the major classes of drugs used in the treatment of hypertension include diuretics (water tablets), beta blockers, angiotensin converting enzyme inhibitors, angiotensin antagonists and calcium antagonists. It is estimated that about 8% of Australians take blood pressure medications which are usually for life.