What is a normal blood pressure?mr.shahadifar
Normal blood pressure is vital to life. Without the pressure that forces our blood to flow around the circulatory system, no oxygen or nutrients would be delivered through our arteries to the tissues and organs.
However, blood pressure can become dangerously high, and it can also get too low.
In this article, we will discuss what blood pressure is, how it is measured, and what the measurements mean for our health.
What is blood pressure?
Blood pressure is the force that moves blood through our circulatory system.
It is an important force because oxygen and nutrients would not be pushed around our circulatory system to nourish tissues and organs without blood pressure.
Blood pressure is also vital because it delivers white blood cells and antibodies for immunity, and hormones such as insulin.
Just as important as providing oxygen and nutrients, the fresh blood that gets delivered is able to pick up the toxic waste products of metabolism, including the carbon dioxide we exhale with every breath, and the toxins we clear through our liver and kidneys.
Blood itself carries a number of other properties, including its temperature. It also carries one of our defenses against tissue damage, the clotting platelets that prevent blood loss following injury.
But what exactly is it that causes blood to exert a pressure in our arteries? Part of the answer is simple – the heart creates blood pressure by forcing out blood when it contracts with every heartbeat. Blood pressure, however, cannot be created solely by the pumping heart.
The National Institutes of HealthTrusted Source cite normal blood pressure to be below 120 mm Hg systolic and 80 mm Hg diastolic.
However, blood pressure changes naturally, a fact that cardiologists explored while writing about blood-pressure variability in NatureTrusted Source in March 2013:
“Blood pressure is characterized by marked short-term fluctuations occurring within a 24-hour period (beat-to-beat, minute-to-minute, hour-to-hour, and day-to-night changes) and also by long-term fluctuations occurring over more prolonged periods of time (days, weeks, months, seasons, and even years).”
The guidelines state that for blood pressures above a figure of 115/75 mm Hg, every rise of 20/10 mm Hg doubles the risk of cardiovascular disease.
The overall guidelines for high blood pressure received an update in November 2017. They allow for earlier intervention.
Since 2017, the American Heart Association (AHA) has advised that people with high blood pressure should receive treatment at 130/80 mm Hg rather than 140/90 mm Hg.
They also removed the “prehypertension” category between 120-139/80-89 mm Hg. A blood pressure reading of 140/90 mm Hg now qualifies as stage II hypertension and not stage I, as it used to be.
This category now forms two separate ranges:
elevated blood pressure, from 120-129/less than 80 mm Hg
stage I hypertension, from 130-139/80-89 mm Hg
In these new guidelines, the AHA also advises that doctors should only prescribe medication in cases of a previous heart attack or stroke, or in the presence of risk factors for these conditions, such as age, a diabetes mellitus diagnosis, or chronic kidney disease.
Treatment at the earlier stages should instead come mainly through lifestyle changes.
Medically reviewed by University of Illinois — Written by Markus MacGill — Updated on January 26, 2021