Hypotension vs hypertension

Posted on 17 September 2014

Keeping your blood pressure stable is key to good cardiovascular health. Dr Kobus Hugo, a GP with special interest in sports medicine, based at the Lowmed Health and Sport Performance Centre in Nelspruit explains the difference between low blood pressure (hypotension) and high blood pressure (hypertension).

What’s the difference between hypotension and hypertension?
Blood pressure (BP) is the measurement of the pressure in a person’s arterial system. The measurement consists of two values – a top and a bottom value, when a doctor is using a blood pressure monitor. The top value is known as the systolic pressure, which is the pressure in the arteries when the heart contracts. The bottom value or diastolic pressure is the pressure in the arteries when the heart relaxes. Normal blood pressure can be any value between 140-100/90-60.

Generally, hypertension is diagnosed when the BP reading is above 140/90. Hypertension can be classified as essential and secondary hypertension. Essential hypertension is where a cause cannot be identified and it occurs in 90-95% of cases. Secondary hypertension is where a cause can be identified and this is usually from a cardiac, arterial, renal or endocrine origin in 5-10% of cases. Hypotension is diagnosed when the BP is less than 90/60. Remember that a sudden drop in blood pressure with feelings of nausea, dizziness and/or chest pain is abnormal and medical advice should be sought without delay.

In terms of developing cardiovascular disease, which of the two is the most dangerous and why?
Hypertension is much more dangerous than hypotension as it can lead to ischaemic heart disease, heart failure, kidney damage, stroke, blindness and aneurysms. Hypertension can damage the inner layer of the coronary arteries, which can lead to occlusion of the arteries and eventually ischaemic heart disease where not enough oxygen is delivered to the heart muscles. High blood pressure can also cause the heart to work harder against a higher resistance, which can lead to left ventricular hypertrophy – a pathological thickening of the heart muscle – which might lead to abnormal heart rhythms and heart failure.

 

The information provided in this article was correct at the time of publishing. At Mediclinic we endeavour to provide our patients and readers with accurate and reliable information, which is why we continually review and update our content. However, due to the dynamic nature of clinical information and medicine, some information may from time to time become outdated prior to revision.