Blood pressure: what it is, how to measure it and table by age

Blood pressure is the pressure that blood exerts within the body’s large arteries and varies according to the elasticity of the vessels, their size and the amount of blood pumped by the heart. In adults, normal systolic pressure ranges from 120 to 129 millimeters of mercury (mmHg) and diastolic pressure ranges from 80 to 84 mmHg.

Although changes in blood pressure do not always have a specific cause, they can occur due to the use of some medications, such as diuretics or antihypertensives, hyperthyroidism and dehydration, for example.

Therefore, correctly measuring blood pressure is important so that changes can be identified properly. Furthermore, it is recommended to consult a cardiologist or general practitioner to confirm the diagnosis and initiate the most appropriate treatment, which may involve the use of medication.

How to measure

Automatic devices or a sphygmomanometer can be used to measure blood pressure and the correct technique varies depending on the device chosen. See how to measure blood pressure correctly.

Before taking the measurement, it is important that the person is sitting comfortably and in a calm environment. In addition, you must have an empty bladder, not smoke, consume alcoholic beverages, coffee or other foods 30 minutes before the measurement, and not do physical exercise in the previous 90 minutes.

See the following video with Dr. Ronaldo Gismondi on how to measure blood pressure correctly:

Blood pressure table by age

The table below shows reference pressure values ​​in mmHg according to age and sex:

If blood pressure is above these values, it is important to consult a cardiologist, general practitioner or pediatrician for an evaluation. In this case, blood pressure measurement may be indicated at other times due to the risk of high blood pressure.

Normal blood pressure

In adults, blood pressure is considered normal when systolic pressure is between 120 and 129 mmHg and/or diastolic pressure is between 80 and 84 mmHg. Furthermore, when blood pressure is below 120 x 80 mmHg, it is considered optimal, however, if it is below 90 x 60 it is generally classified as hypotension.

In children, the normal blood pressure value varies according to age, sex and height, and can be considered normal when lower than the 90th percentile for systolic and diastolic pressure.

Causes of high blood pressure

High blood pressure can be caused by hormonal changes, such as hyperthyroidism and Cushing’s syndrome, and kidney diseases, such as chronic kidney disease or polycystic kidneys, for example. In addition, some medications, smoking and excessive alcohol consumption can also cause high blood pressure.

In adults, high blood pressure, or hypertension, is typically considered when the person’s home blood pressure is above 130 x 80 mmHg. When measured in a doctor’s office, hypertension is normally when blood pressure is above 140 x 90 mmHg.

Read too: High blood pressure: what it is, symptoms, causes, remedies (and more)

Causes of low blood pressure

Low blood pressure, or hypotension, is when blood pressure is less than 90 x 60 mmHg, which can occur due to the use of some medications, such as diuretics and antihypertensives, dehydration, heart problems and serious infections.

Read too: Low blood pressure: symptoms, causes and what to do

However, the cause of low blood pressure is not always identified and may not be of concern in some cases, especially when symptoms such as weakness or drowsiness do not occur.