http://www.ck12.org Chapter 1. Human Biology
- Diastolic: less than 80
Blood pressure is usually written as systolic/diastolic. For example, a reading of 120/80 is said as "one twenty over
eighty." These measures of blood pressure can change with each heartbeat and over the course of the day. Pressure
varies with exercise, emotions, sleep, stress, nutrition, drugs, or disease.
Studies have shown that people whose systolic pressure is around 115, rather than 120, have fewer health problems.
Clinical trials have shown that people who have blood pressures at the low end of these ranges have much better
long term cardiovascular health. Blood pressure is measured with a sphygmomanometer (Figure1.50).
FIGURE 1.50
A digital sphygmomanometer is made of
an inflatable cuff and a pressure meter
to measure blood pressure. This reading
shows a blood pressure of 126/70.Hypertension, which is also called "high blood pressure," occurs when a person’s blood pressure is always high.
Hypertension is said to be present when a person’s systolic blood pressure is always 140 or higher, and/or if the
person’s diastolic blood pressure is always 90 or higher. Having hypertension increases a person’s chance for
developing heart disease, having a stroke, or suffering from other serious cardiovascular diseases. Hypertension
often does not have any symptoms, so a person may not know that he or she has high blood pressure. For this
reason, hypertension is often called the silent killer. Treatments for hypertension include diet changes, exercise, and
medication.
Vocabulary
- blood pressure: Pressure that circulating blood puts on the walls of blood vessels.
- diastolic: Blood pressure when the heart is resting between beats.
- hypertension: High blood pressure.
- systolic: Blood pressure when the heart constricts.
Summary
- Blood pressure occurs when circulating blood puts pressure on the walls of blood vessels.
- Hypertension, or high blood pressure, can increase the risk of cardiovascular disease.