The heart forcefully pumps blood into the arteries. This creates pressure on the blood vessels. Blood pressure is therefore the pressure of the blood in the arteries. Blood pressure is the pressure placed on the walls of the blood vessels every time the heart contracts. Two blood pressure values are distinguished, namely the upper pressure (or systolic blood pressure) and the negative pressure (or diastolic blood pressure). Blood pressure is measured in millimeters of mercury (mm Hg). For example, blood pressure can be read as ‘120 over 80’, which represents upper and lower pressure respectively. Normal blood pressure is 120/80 or lower.
- Two blood pressure values: negative pressure and upper pressure
- Two numbers
- Systolic blood pressure
- Diastolic blood pressure
- How is blood pressure measured?
- Accurate blood pressure measurement
- Multiple blood pressure measurements
- When does high blood pressure occur?
- Blood pressure table: blood pressure values
- What are the consequences of high blood pressure?
- What causes high blood pressure?
- Risk factors
- Additional causes of high blood pressure
- Keep your blood pressure low
- When does low blood pressure occur?
- Lower blood pressure through lifestyle changes
Two blood pressure values: negative pressure and upper pressure
Two blood pressure values are distinguished:
- the upper pressure (systolic blood pressure); and
- the negative pressure (diastolic blood pressure).
Systolic blood pressure is measured when the left ventricle contracts. The pressure is then highest. When the heart relaxes and the left ventricle fills with blood again, blood pressure is at its lowest. The pressure that occurs between two contractions of the heart, when the heart relaxes, during the resting phase of the heart, is called diastolic blood pressure.
Two numbers
When measuring blood pressure, two values are recorded: the upper pressure and the lower pressure and these are expressed in millimeters of mercury (mm Hg). When reading blood pressure, the upper pressure is first mentioned and then the negative pressure. For example, 120/80 mm Hg is pronounced ‘120 over 80’, which refers to the upper and lower pressure respectively.
Systolic blood pressure
When the heart contracts, blood is pumped through the arteries to the rest of the body. This force puts pressure on the arteries. This is called systolic blood pressure. A normal or ideal systolic blood pressure is 120 or lower. A systolic blood pressure of 120-139 means you have prehypertension. This means that you do not yet have high blood pressure, but there is a chance that you will develop it. Even people with prehypertension have a higher risk of developing cardiovascular disease. A systolic blood pressure of 140 or higher is considered hypertension, or high blood pressure.
Diastolic blood pressure
Diastolic blood pressure represents the pressure in the blood vessels when the heart rests between beats. This is the time when the heart fills with blood and receives oxygen. The normal or ideal diastolic blood pressure is 80 or lower. A diastolic blood pressure between 80 and 89 indicates prehypertension. A diastolic blood pressure of 90 or higher is considered hypertension or high blood pressure. By the way, it is almost impossible for someone to have a normal upper pressure and at the same time an excessively high negative pressure (of more than 90). In almost all cases, a negative pressure of more than 90 is accompanied by a systolic pressure of more than 140.Blood pressure measurement by a doctor / Source: Kurhan/Shutterstock
How is blood pressure measured?
Accurate blood pressure measurement
Blood pressure is measured by a doctor with two instruments: a cuff (developed by the Italian Riva Rocci), which is connected to a pressure gauge and a stethoscope. The inflatable cuff is placed around the upper arm. Some blood pressure cuffs are wrapped around the forearm or wrist, but these are often not very accurate. When measuring blood pressure, the doctor or nurse will use a stethoscope by placing it on the brachial artery. This listens to the murmur of the artery in the arm, which is necessary for a good blood pressure measurement. The cuff is inflated to a pressure known as the palpatory systolic blood pressure; the doctor feels the pulse while inflating and continues until the pulse disappears. He then pumps another 20 mm Hg and then closes the valve. With the stethoscope in his ears, he listens in the bend of his elbow, where nothing can be heard. Then he carefully lets air escape. When the cuff deflates, the first sound he hears through the stethoscope is the systolic blood pressure. It sounds like a whooshing sound. When this noise disappears completely, the diastolic blood pressure can be read. People can use digital blood pressure monitors at home, so that you can measure and monitor your blood pressure yourself.Measure your blood pressure at home / Source: Bacho/Shutterstock
Multiple blood pressure measurements
Blood pressure changes constantly depending on the time of day; in the morning and evening blood pressure is slightly lower than in the afternoon. Blood pressure also increases with exertion (cycling, walking), strong emotions and excitement or with a change in position, but often also with the doctor. This is then referred to as ‘white coat blood pressure’, where the blood pressure is increased as a result of the tension of the measurement. That is why one measurement is completely insufficient. Blood pressure must be measured between 3-5 times over a period of weeks to months before hypertension or high blood pressure can be diagnosed.
When does high blood pressure occur?
The ideal blood pressure (the target blood pressure) for adults of both sexes is a pressure of approximately 120/80 mm Hg; for the elderly it may be slightly higher. There is elevated blood pressure at values of 140/90 mm Hg or higher. For persons aged 60 (sometimes older, depending on the source consulted) and older, a limit of 160 mm Hg systolic is used, if there is no:
- diabetes;
- familial hypercholesterolemia (an inherited condition in which the cholesterol level in the blood is too high); or
- have cardiovascular disease.
The aim is to keep or bring the systolic blood pressure below 140 mm Hg, preferably below 120, and the diastolic blood pressure below 90 mm Hg, preferably 80.
Blood pressure table: blood pressure values
A distinction is made between mildly, moderately and severely elevated values. This distinction is made with the negative pressure and not with the upper pressure. Usually both are elevated. In that case, the classification only focuses on the negative pressure.
| Classification | Values |
| Slightly increased diastolic pressure | 95 to 104 mm Hg |
| Moderately elevated diastolic pressure | 105 to 114 mm Hg |
| Severe diastolic pressure | 115 mm Hg or more |
| Increased systolic pressure | 160 mm Hg or more |
What are the consequences of high blood pressure?
High blood pressure leads to vessel wall damage and thus to arteriosclerosis or atherosclerosis. In addition, the vessel wall becomes thicker and less elastic. These consequences increase the risk of heart attack or stroke. High blood pressure can also lead to kidney disease, and is closely linked to some forms of dementia.Walking is healthy for the heart and blood vessels / Source: Robert Kneschke/Shutterstock
What causes high blood pressure?
Risk factors
It is not known exactly what causes high blood pressure. Usually no cause for high blood pressure can be found. It is known that your lifestyle can influence the development of high blood pressure. Risk factors are:
- too much salt intake;
- not eating enough fruit and vegetables;
- not being physically active enough;
- obesity or obesity;
- drinking too much alcohol.
You can lower your blood pressure and thus reduce the risk of stroke and heart attack by making lifestyle changes.
Additional causes of high blood pressure
There are a number of factors that increase the risk of developing high blood pressure, but they are unchangeable. These factors are:
- Age: As you get older, the effects of an unhealthy lifestyle can add up and increase your blood pressure. In addition, the stiffness of the vessels increases with age.
- Ethnic origin: People from Afro-Caribbean and South Asian communities are at greater risk than other people for high blood pressure.
- Family history: you are at greater risk if immediate family members also have (had) high blood pressure.
Some people have high blood pressure that stems from another condition, such as kidney problems. For these people, blood pressure can be lowered as soon as the underlying condition is adequately treated.
Keep your blood pressure low
Even if you don’t currently have high blood pressure, it’s important to keep your blood pressure as low as possible. The higher your blood pressure, the higher your risk of health problems. For example, you may have a blood pressure of 135/85 and be okay with this, but someone with these values is twice as likely to have a heart attack or stroke as someone with a blood pressure of 115/75.
When does low blood pressure occur?
Low blood pressure or hypotension only occurs when the blood pressure is so low that you experience discomfort in the form of complaints such as dizziness and fainting. The pressure is often below 90/60. Low blood pressure can affect anyone, young and old, male and female.
Lower blood pressure through lifestyle changes
You can lower your blood pressure by making certain lifestyle changes. Read which ones here.
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