man measuring his blood pressure

The causes of hypertension vary between patients and can be difficult to establish. Narrow, stiff or clogged arteries cause higher blood pressure. In more than 90% of patients, it is very difficult to determine one clear-cut cause of hypertension and most doctors suspect, that there is a variety of issues at play.

It is important that you get a medical check-up so that your doctor can try to determine the reasons for your high blood pressure.

If you have been diagnosed with high blood pressure, you can order a repeat prescription for your medication online. Our doctors can prescribe most UK brands (Diovan, Aprovel, Amias) and send you a 3-6 month course via our partner pharmacy.

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What causes high blood pressure?

Blood pressure is the result of the amount of blood pumped through your body by the heart and your arteries' resistance to the blood flow. High blood pressure occurs when your arteries cannot dilate properly to accommodate changes in blood flow.

High blood pressure takes many years to develop, and usually causes no symptoms at all. Most people will discover they have it when they go for a medical check-up, suffer a heart attack or develop erectile dysfunction.

As we age, our arteries become stiffer and less flexible, therefore a certain increase in blood pressure is normal over the years. However, abnormally high blood pressure is a real problem that can lead to heart attack and stroke. Over time, the excessive pressure on the walls of your arteries will cause damage to the arteries.

Technically speaking, what causes high blood pressure are narrow, stiff and/or clogged arteries. It can be difficult to understand exactly what is causing this narrowing or clogging.

However, it is very quick and easy to diagnose hypertension. After that, you need to work with your GP, who will develop a treatment plan for you.

Essential (or primary) hypertension

The most common form of high blood pressure is called essential hypertension. It affects about 90-95% of cases of hypertension and doctors usually cannot identify the exact reason for high blood pressure of this type. It is asumed that a number of factors contribute to hypertension.

These factors include (full list in the "risk factors" section):

  • Lifestyle
  • Diet – too much fat, salt or coffee
  • Age
  • Gender – men are more at risk than women
  • Ethnicity
  • Genetic disposition (family history of hypertension)

Essential hypertension develops slowly over the years, which is why it is symptom-less (or asymptomatic) most of the time – until something triggers a heart attack, stroke or another condition.

Secondary hypertension

The second most common cause of high blood pressure is called secondary hypertension. It represents 5-10% of cases of hypertension and is caused by an underlying condition.

Possible causes of secondary hypertension include: kidney disease, hormonal disease (e.g. gland tumour, hyperthyroidism), lead poisoning, head injuries and pregnancy.

Many of these causes of secondary hypertension are temporary and/or curable. Some medications and drugs can also cause secondary hypertension. These include antidepressants, cocaine, amphetamines, NSAID (non-steroidal anti-inflammatory drugs such as aspirin or ibuprofen in high quantities), decongestants, etc.

Less common causes

Isolated systolic hypertension is a much less common type of hypertension. It happens, when only the first number of your blood pressure is too high, for example 140 in 140/80 (read 140 over 80).

This number represents the systolic blood pressure (when blood is pumped into the vessels), as opposed to the diastolic blood pressure (the second number, when the heart is at rest).

This disease causes high blood pressure only when the heart is pumping blood, after which the blood pressure goes back to normal. This creates a huge chronic difference in blood pressure, which swings up and down putting great strain on your arteries.

Causes of isolated systolic hypertension (or ISH) include advanced age, anaemia (lack of red blood cells), thyroid hormone diseases and heart conditions.

Another reason for high blood pressure – called white-coat hypertension – is not as serious as the other types and happens because of the stress of being in a hospital or clinic and receiving treatment there. It is not really a case of high blood pressure as a condition but is simply a case of increased blood pressure due to stress.

This can lead to misdiagnosis, so try to relax as much as possible when in hospital or with your doctor.

High Blood Pressure Risk factors

Lifestyle-related risk factors:

  • Smoking raises your blood pressure, and most importantly it damages your arteries in the long run
  • Lack of exercise: the arteries will lose the ability to adapt to changes in blood flow (by expanding or narrowing), thus leading to earlier aging and hardening of your arteries
  • Obesity: as your weight increases, you need more blood to “feed” your tissues in oxygen and nutrients. This means that your arteries are gradually transporting much more blood than they were originally “designed” for
  • Stress may trigger stroke and heart attack as it can temporarily lead to huge increases in blood pressure
  • Unhealthy diet: too much alcohol, salt, coffee as well as lack of potassium and vitamin D will contribute to an increase in blood pressure. Binge drinking also damages the heart

Other relevant factors include:

  • Age: the older you get the higher your blood pressure is because of the natural hardening of the arteries
  • Family background: there is a genetic aspect to hypertension which is often inherited
  • Ethnicity: some ethnic groups are more at risk of high blood pressure than others, for example people from South Asian (e.g. India) and Caribbean origins

And finally the disease-related risk factors:

  • High cholesterol, which narrows your blood vessels
  • Diabetes: 30% of people with type 1 diabetes and 50% of those with type 2 will develop high blood pressure over time
  • Kidney disease

There is a whole range of other diseases that can contribute to high blood pressure. You should also know, that risk factors usually add up, meaning that the more risk factors you accumulate (for example in the case of a 65 year old overweight smoker with diabetes), the higher your risk of high blood pressure, heart attack or cardiovascular disease (i.e. heart and blood vessels disease).

How common is high blood pressure in the UK ?

In the UK, as well as in many other countries, hypertension remains under-diagnosed. Tens of thousands of people are at risk and unaware their condition until they eventually suffer from complications - such as stroke, heart attack or impotence.

30-35% of men aged over 40-45 suffer from high blood pressure and around 25% of women the same age have hypertension. About half of British people aged over 65 have hypertension. In people over the age of 75, high blood pressure affects 75% of men and 65% of women.

The threshold that determines who has hypertension and who hasn’t, is a blood pressure reading equal to or over 140/90 (140 over 90). The higher the blood pressure is, the greater the risk of developing other serious conditions.

The lack of treatment and screening of high blood pressure means that too many people in the UK suffer from this preventable disease. Thousands of lives could be saved every year if people age over 50 had their blood pressure checked regularly.

Measuring blood pressure

You need to understand what causes high blood pressure to realise whether you are part of the population at risk or not.

If you worry you might be at risk, get into the habit of getting your blood pressure checked regularly. If you know that you are at risk (e.g. diabetes, age over 65, mild hypertension) you need to get your blood pressure measured at least once every year.

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