High blood pressure


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Many people have high blood pressure (hypertension). But they usually don't notice it – which means that over time it can damage blood vessels. Having blood pressure that is always too high can make you more likely to have a heart attack, a stroke or kidney problems. The higher your blood pressure, the greater your risk of developing these medical conditions.

Blood pressure readings have two values that are always listed together: 128/85 mmHg, for example. The first number represents the pressure in the blood vessels when the heart muscles squeeze (systolic blood pressure). The second represents the pressure in the blood vessels when the heart muscles relax (diastolic blood pressure).

Blood pressure is considered to be too high if the systolic value is over 140 and/or the diastolic value is over 90. But these levels were set for practical reasons and act only as a general guide. Because of this, recommendations about when medication is needed to treat high blood pressure may vary.


High blood pressure itself usually goes unnoticed. Only if it is extremely high can it result in symptoms like dizziness or vision problems.

Causes and risk factors

Our bodies are able to regulate blood pressure as needed. It's typically low when we relax or sleep. It increases when, for example, we do hard physical work and our muscles need more blood. Stress or fear can also cause your blood pressure to go up. It usually naturally increases with age in most people as well.

So it's normal for blood pressure readings to vary; that's 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 various health problems.

Often no specific cause is found for high blood pressure. Then doctors call it "essential" or "primary" hypertension.

Being overweight, eating a lot of salt, drinking too much alcohol and not getting enough exercise can increase your blood pressure. But slim, athletic people who watch what they eat may also develop high blood pressure – for example, because it runs in their family.

An exact cause is only found in 5 out of 100 people. Possible causes include an overactive thyroid gland (hyperthyroidism) or kidney disease. When the cause is known, doctors refer to it as "secondary" hypertension.

Sometimes medications can increase blood pressure as well. For example:

  • Some medicines used to treat psychological illnesses
  • Certain plant-based medications like St. John's wort
  • Decongestant nasal sprays or drops
  • Birth control pills


Long-term high blood pressure can increase the likelihood of cardiovascular (heart and blood vessel) diseases and cause organ damage. The possible long-term effects of high blood pressure include the following:

Treatment can lower the risk of developing these kinds of problems.


Blood pressure is measured in units of “millimeters of mercury,” written “mmHg” for short. It is always measured while you are resting so that the readings can be compared and interpreted more easily. Blood pressure is measured on several days to get a more reliable result than a single reading can offer. It's also important to measure blood pressure on both arms because the pressures may differ. The highest systolic reading and the highest diastolic reading are then taken as the basis for determining your blood pressure.

An adult’s blood pressure is considered to be normal if it is less than 140 over 90 (140/90). High blood pressure is diagnosed if

  • the systolic reading is greater than 140 mmHg,
  • the diastolic reading is greater than 90 mmHg, or
  • both readings are greater than these values.

Sometimes blood pressure is measured over a 24-hour period (ambulatory blood pressure monitoring). This might be done if individual measurements vary a lot. To do that, you carry a portable instrument with you that measures your blood pressure at regular intervals.


In Germany, statutory health insurers cover the cost of a general health check-up every three 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 includes taking your blood pressure. So far, though, studies haven’t proven that regular general health check-ups can protect healthy people from illness or increase their life expectancy.


There are a number of things you can do on your own to lower high blood pressure. Some people manage to keep their blood pressure under control by

  • losing a little weight,
  • eating less salt, and
  • getting more exercise.

If that doesn't work, medication can also be used to lower blood pressure. Before you decide to take medication, it's worth considering the pros and cons. That's because some people benefit less from medication than others, and the medication may have side effects.

Further information

When people are ill or need medical advice, they usually go to see their family doctor first. Read about how to find the right doctor, how to prepare for the appointment and what to remember.

Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Reduction of salt intake in essential hypertension: Rapid Report; Commission A05-21B. June 18, 2009. (IQWiG reports; Volume 54).

Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Increase of physical activity in essential hypertension: Rapid Report; Commission A05-21D. August 23, 2010. (IQWiG reports; Volume 75).

Semlitsch T, Jeitler K, Berghold A, Horvath K, Posch N, Poggenburg S et al. Long-term effects of weight-reducing diets in people with hypertension. Cochrane Database Syst Rev 2016; (3): CD008274.

Whelton PK, Carey RM, Aronow WS, Casey DE, Collins KJ, Dennison Himmelfarb C et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol 2018; 71(19): e127-e248.

Williams B, Mancia G, Spiering W, Agabiti Rosei E, Azizi M, Burnier M et al. ESC/ESH Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Cardiology and the European Society of Hypertension. J Hypertens 2018; 36(10): 1953-2041.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on May 23, 2019

Next planned update: 2024


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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