High Blood Pressure: introduction
High blood pressure, also known as hypertension, is an often-symptomless condition that acts as a clinical risk factor for various other diseases and conditions.
The beating of the heart causes blood to circulate through the body at inconsistent rate. This causes blood pressure to vary naturally from minute to minute. Therefore, when blood pressure is measured over time, the beating of the heart causes peaks and troughs. These peaks and troughs are referred to as systolic and diastolic blood pressure respectively. Blood pressure is recorded as systolic/diastolic, e.g. as 140/90 mmHg (pressure equivalent of millimetres of mercury).
When blood pressure remains elevated beyond normal levels for a sustained period of time, damage to the blood vessels and other organs such as the kidneys occurs. This, in turn, can cause a number of other diseases to develop including:
- coronary heart disease (angina, heart attack)
- stroke (both that due to a blood clot and that due to bleeding)
- heart failure (heart strain - especially left ventricular)
- aortic aneurysm (dilated aorta with risk of rupture and massive internal haemorrhage)
- peripheral vascular disease (reduced blood supply to the limbs)
- chronic kidney disease (including renal failure)
- retinal disease (visual impairment)
High blood pressure has a significant impact on morbidity and mortality in Scotland and world-wide, with the Global Burden of Disease study (2021) reporting that the condition is the second greatest risk factor contributing to death and disability in Scotland, after tobacco smoking.
Management of high blood pressure at population level is challenging due to the high prevalence of the disease and its usually symptomless nature. The Scottish Health Survey estimated in 2022 that 22% of those over the age of 16 in Scotland had been diagnosed with the condition. These estimates of prevalence may still significantly underestimate true prevalence, with the 2019 iteration of the Scottish Health Survey reporting that the high blood pressure detection rate in Scotland was stable at 59%.
Hypertension is diagnosed by taking blood pressure measurements from each arm. If blood pressure exceeds the standard of 140/90mmHg defined by the National Institute for Health and Care Excellence (NICE), a second measurement should be taken. If this measurement also exceeds the threshold, treatment should be considered.
Treatment for hypertension is primarily concerned with managing modifiable risk factors for the condition through lifestyle changes, for example by reducing sodium and alcohol intake and by quitting smoking. Anti-hypertensive drugs may also be prescribed to those with other conditions such as diabetes or to those at risk of organ damage due to the condition.
