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Michelle Loewenstein
3 minute read
22 Nov 2013
6:00 am

High blood pressure: The silent killer

Michelle Loewenstein

Many articles have been published on the dangers of high blood pressure, also known as hypertension. However, relatively little information is readily available on low blood pressure (hypotension).

Image courtesy Stock.xchnge

According to, your blood pressure is expressed as systolic/diastolic blood pressure – for example, 120/80. The systolic blood pressure (the top number) represents the pressure in the arteries as the muscle of the heart contracts and pumps blood into them. The diastolic blood pressure (the bottom number) represents the pressure in the arteries as the muscle of the heart relaxes following its contraction.


Image courtesy Stock.xchnge

Image courtesy Stock.xchnge


A normal blood pressure reading would be 120/80 at rest. Low blood pressure symptoms occur when blood pressure is less than 90/60.

Dr Tai Seng Shierenberg, general manager at Netcare Sunning-hill Hospital, answered a few questions about this physiological problem.

What causes low blood pressure?

Insufficient blood volume, blood loss or dehydration or electrolyte imbalance can cause it. Insufficient vascular tone, such as sudden severe infection or septic shock, as well as insufficient output from the heart due to a weak heart or a heart that beats irregularly, too slowly, or too fast can also be a cause. One of the rarer reasons the heart beats abnormally is due to conduction disturbances within the heart muscle, whereby the electrical impulses are conducted along pathways that are diseased or abnormal.

This could be congenital or due to an ageing heart which is chronically deprived of blood and oxygen or due to a number of other causes including drug side effects, metabolic disturbances etc.

There are a number of additional underlying causes to low blood pressure, including pulmonary embolus, acute myocardial ischemia (when a heart muscle is acutely deprived of oxygen), aortic stenosis, myocarditis and pericarditis (inflammation of heart muscle and covering respectively), hormonal disturbances (adrenal insufficiency) and side effects from drugs.


Image courtesy Stock.xchnge

Image courtesy Stock.xchnge


What are the symptoms?

Weariness, feeling weak or tired, feeling light headed, impaired vision, dizziness, especially when standing up, loss of consciousness, and falls.

What are the dangers of having low pressure?

You can succumb to the underlying pathology or the underlying causes if it goes unrecognised and untreated. If you lose consciousness and fall over, then obviously you will run a high risk of injury to head, spine, hips, legs and other long bones, which easily fracture in the elderly.

Is it as dangerous as high blood pressure?

The dangers are different and usually more acute and short term in nature, so you must take low blood pressure seriously. The ffects of high blood pressure evolve over time and can be managed with appropriate drug therapy.

How is low blood pressure treated?

Doctors will identify and address the cause. If it is a very acute problem such as a haemorrhage, severe dehydration, sepsis or cardiac event, the patient will need to seek emergency help and will be presented to an emergency department in hospital, and/or consult with a physician or a specialist cardiologist or surgeon in the case of acute blood loss due to injury.


Blood Pressure Monitor in a Doctor's Office. Image courtesy Stock.xchnge

Blood Pressure Monitor in a Doctor’s Office. Image courtesy Stock.xchnge


How do you know if dizziness is normal or if it is a sign of a low blood pressure problem?

Have your blood pressure measured and a thorough examination of your cardiovascular system. Have your doctor check, or check yourself for any signs suggestive of the above conditions. Hypotension could be the problem if you get dizzy when standing up. Likewise the blood pressure will noticeably drop from measured when lying down and then changing to the standing position.

Why do you think this affliction doesn’t get much attention in comparison to other illnesses?

It is a sign of serious underlying pathology and certainly receives acute attention if a patient presents in hospital, where it would be aggressively managed by managing underlying causes. Having said that, a lot of elderly people suffer falls and sustain injuries as a result. Often the question to ask is: why did this patient fall? Is there some underlying cardiac problem that has gone unnoticed and untreated?