What is blood pressure?
Blood pressure is a measurement of the force applied to the walls of the arteries as the heart pumps blood through the body. The pressure is determined by the force and amount of blood pumped, and the size and flexibility of the arteries.
Blood pressure is continually changing depending on activity, temperature, diet, emotional state, posture, physical state, and medication use.
How is blood pressure measured?
Blood pressure readings are measured in millimeters of mercury (mmHg) and are given as two numbers. For example, 110 over 70 (written as 110/70).
The top number is the systolic blood pressure reading. It represents the maximum pressure exerted when the heart contracts.
Why the Test is Performed
The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends screening adults for high blood pressure every 2 years if their blood pressure is normally less than 120/80 mmHg.
Adults with high blood pressure or prehypertension should have their blood pressure checked every year or more often.
Most people cannot tell if their blood pressure is high because there are usually no symptoms.
High blood pressure increases the risk of heart failure, heart attack, stroke, and kidney failure.
If you have high blood pressure, blood pressure measurements can help determine if your medicine and diet changes are working.
Low blood pressure may be a sign of a variety of illnesses, including heart failure, infection, gland disorders, and dehydration.
In adults, the ideal top number (systolic pressure) should be less than 120 mmHg. The bottom number (diastolic pressure) should be less than 80 mmHg.
The bottom number is the diastolic blood pressure reading. It represents the minimum pressure in the arteries when the heart is at rest.
What Abnormal Results Mean
Top number is consistently 120 to 139 or the bottom number reads 80 to 89.
Stage 1: Mild high blood pressure:
Top number is consistently 140 to 159 or the bottom number reads 90 to 99.
Stage 2: Moderate to severe high blood pressure:
Top number is consistently 160 or over or the bottom number reads 100 or over.
Low blood pressure (hypotension):
Top number reading lower than 90 or pressure 25 mmHg lower than usual
Blood pressure readings may be affected by many different conditions, including:
- Cardiovascular disorders
- Neurological conditions
- Kidney and urological disorders
- Pre-eclampsia in pregnant women
- Psychological factors such as stress, anger, or fear
- Various medications
- “White coat hypertension” may occur if the medical visit itself produces anxiety
This information is from ”Blood Pressure” at Medline Plus.