Many people have high blood pressure (hypertension), but they usually do not notice it – which means that over time it can damage blood vessels. Having blood pressure that is consistently too high can make you more likely to develop health problems like heart attack, stroke or kidney damage.
Blood pressure readings have two values that are always listed as a pair: 128/85 mmHg, for example. Systolic blood pressure (the higher one) comes first, followed by diastolic blood pressure (the lower one). Blood pressure is measured in units of “millimeters of mercury,” written “mmHg” for short.
Blood pressure is considered to be too high if the systolic value is over 140 mmHg and/or the diastolic value is over 90 mmHg. However, these levels were set for practical reasons and act only as a general guide. Experts do not fully agree on what value should be taken as the value above which high blood pressure needs to be treated. There is also no consensus on the value blood pressure should be lowered to.
High blood pressure itself usually goes unnoticed. It only causes symptoms like dizziness or vision loss when it is extremely high.
Causes and risk factors
Our bodies are able to regulate blood pressure as needed. For example, when we do hard physical work and our muscles need more energy, our blood pressure increases. Stress or fear can also cause blood pressure to go up. Our blood pressure is lower when we relax or sleep. Blood pressure generally increases with age.
So it is normal for blood pressure readings to vary; that is just a sign of an active life. But if blood pressure is too high for too long, it can damage blood vessels over time and increase the risk of serious health problems.
Many people are affected by high blood pressure. An exact cause can only be found in 5 out of 100 people. In rare cases high blood pressure is the direct result of an organ disease such as an overactive thyroid or a kidney problem. This kind of cause is more common in younger people under the age of 40. Some types of medication may also increase blood pressure.
When no clear cause is detected, doctors usually refer to high blood pressure as "essential" or "primary" high blood pressure. Even when it is not clear what the exact cause is, there are a few known contributing factors, such as overweight, eating a lot of salt, drinking too much alcohol and not getting enough exercise.
Long-term high blood pressure can increase the likelihood of cardiovascular diseases and cause organ damage. Possible complications of high blood pressure include the following:
- Poor blood circulation in the legs
- Weakened heart muscles (myocardial insufficiency)
- Heart attack
- Damage to the kidneys
Treatment can lower the probability of developing these kinds of complications.
Blood pressure can be measured using an instrument called a sphygmomanometer or with a digital blood pressure meter. Blood pressure is usually measured when the person is at rest so that the blood pressure readings can be compared and interpreted more easily. Taking just one reading is not considered reliable enough. Instead, a total of two readings are taken on two different days. In some cases, blood pressure is also measured during exercise or over the course of 24 hours (ambulatory blood pressure). It is important to measure blood pressure on both arms because the pressures may differ. The higher set of readings is then taken as the basis for determining whether you have high blood pressure.
In adults, blood pressure is considered to be normal under a systolic value of 140 mmHg and under a diastolic value of 90 mmHg. Blood pressure used to be considered too high if the systolic value was over 160 mmHg. Nowadays blood pressure is considered to be too high if it is above 140/90. In other words, if either the systolic value is above 140, the diastolic value is above 90, or both values are too high.
In Germany, statutory health insurance covers the cost of a general health check-up every two years from the age of 35 onwards. The aim of this check-up is to detect early signs of cardiovascular disease, diabetes and kidney problems. It involves things like having your blood pressure taken, and blood and urine tests.
There are some things you can do on your own to lower high blood pressure. Changing your eating habits and getting more exercise can help. Lowering your salt intake is particularly helpful.
There are also effective drugs designed to lower blood pressure and prevent related medical problems. But before you decide to start taking medication, it is worth considering the advantages and disadvantages.
Poulter NR, Prabhakaran D, Caulfield M. Hypertension. Lancet May 27, 2015 [Epub ahead of print].
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