What is Blood Pressure?

Submitted by Thiruvelan on Wed, 06/23/2010
Hypertension

Blood pressure sometimes called arterial blood pressure is the pressure exerted by circulating blood against the walls of blood vessels.

Studies show one in every three adults has high blood pressure, but one-third of them unknowingly having hypertension.

Define Blood Pressure?

Our body cells need nutrients and oxygen to get their energy requirement by burning it; blood circulation provides this. Nutrient and oxygen-rich blood transported from the heart to all part within the body. The heart pumps out blood with some pressure so that it can easily reach extremes. During the heart pump, blood has the pressure that exerts over the wall of the arteries called blood pressure.

Discovery of blood pressure! Stephen Hales, a British veterinarian who in 1733 inserted a brass pipe into the artery of a horse and connected the hose to a glass tube. He noticed that the blood through the glass tuberose and concluded that pressure was pushing the blood. However, Hales had no way to measure the pressure and prove his theory.

What are the factors that determine your Blood Pressure?

The pressure in your arteries depends on a couple of crucial factors. These factors are baroreceptors (pressure sensors in arteries & veins), blood volume, heart’s ability to pump, cardiac output, heart rate, and blood vessel elasticity.

  1. Baroreceptors – are pressure sensors in your body. Healthy blood pressure maintenance depends on the ability of baroreceptors to measure the pressure. 
  2. Blood volume - When the heart pumps more blood with every heartbeat, then the blood pressure will be higher. On the other hand, if the heart pumps lesser blood with every heartbeat, then the blood pressure will be lower.
  3. Hearts ability to pump - Proper functioning of heart valves is vital for the heart's ability to pump blood through the body. Regurgitation (valve leakage), stenosis (valve narrowing), and atresia (valve not appropriately developed in a child) are some heart’s inability to pump blood properly.
  4. Cardiac output – is the volume of blood being pumped by the heart in a minute. It is equal to the heart rate multiplied by the stroke volume. So, if there are 70 beats per minute, and 70 ml of blood pumped with each beat of the heart, the cardiac output is 4900 ml/ minute.
  5. Heart Rate - Heart rate is the measure of the number of heart contractions per minute (bpm). The heart rate can vary according to your body's oxygen requirement and how well it excrete carbon dioxide.
  6. Blood vessel elasticity - The presence of thick or narrow artery wall resist blood flow results in high blood pressure. On the other hand, a dilated artery wall exerts reduced resistance results in low blood pressure.

Additionally, it also depends on how properly your kidneys, liver, and vessels work. Without knowing why the pressure is high, you cannot treat hypertension properly.

How does your body maintain healthy Blood Pressure?

Baroreceptors are sensors in the blood vessels that sense the blood pressure. It sends the details to the brain so that the brain maintains healthy blood pressure by communicating with the kidneys, arteries, veins, and heart to increase, decrease, or maintain blood pressure, as needed. Its function is to ensure all the organs and tissues receives sufficient blood supply.

If your blood pressure is too high, baroreceptors send a signal to the brain. The brain instructs

  • The heart to beat slower, pump less blood per beat,
  • Relaxes the arteries that carry oxygen-enriched blood from the heart,
  • Constrict the veins that carry oxygen-depleted blood to the heart.

It results in a drop in blood pressure until they attain healthy blood pressure.

On the other hand, if your blood pressure is too low, baroreceptors send signals to the brain. The brain instructs

  • The heart to beat faster, pump more blood per beat,
  • It increases blood pressure by constricting the arteries that carry oxygen-enriched blood from the heart.
  • Relaxes the veins that carry oxygen-depleted blood to the heart.

It results in a rise in the blood pressure until it attains a healthy blood pressure.

If the above said control loop not able to maintain healthy blood pressure, then the next master control system involving the kidney is pressed into the service.

  • If the blood pressure is high, kidney pulls more water out of the blood by excreting more urine than usual thus decrease blood pressures.
  • If the blood pressure is low, the kidney keeps more water in the blood by excreting less urine than usual, thus increases blood pressure.

This control loop is slow acting; it takes hours compared to rapid baroreceptor control.

What Is Healthy & High Blood Pressure?

The left lower chamber (ventricle) of the heart receives oxygenated blood from the lungs and heart pumps blood throughout the body. The blood flow exerted pressure on the arteries during the heartbeat is called the systolic blood pressure. It is the first or top number in a blood pressure reading. The pulse you feel is the contraction of the heart's left ventricle.

The heart fills with blood between heartbeats. During this period, the blood pressure drops on the arteries called the diastolic blood pressure.

For any reason, if the blood pressure stays higher (between 140/90 and 159/99 mmHg) for an extended time, then call it as High Pressure. The medical term for high blood pressure is hypertension.

Studies show one in every three adults has high blood pressure, but one-third of them unknowingly having hypertension. Because the hypertension symptoms are difficult to predict, so it goes unnoticed.

Uncontrolled hypertension for a long time might lead to hypertension complications such as coronary heart disease, heart failure, stroke, and kidney failure. That is why hypertension is considering as the “Silent KILLER.” The only way to diagnose hypertension is to check blood pressure. So, if you have many of the high blood pressure risk factors and experiencing symptoms of high blood pressure, then you need to go for blood pressure diagnosis.

High blood pressure measured in the doctor’s office may be sometimes falsely high, because

As much as 20 % suffered from "white coat syndrome." Blood pressure surges in the doctor's office. Otherwise, the BP is normal at home. 

Knowing about white-coat syndrome helps to stop misdiagnosed as hypertension. Also, you need to repeat blood pressure measurement many times preferable outside the doctor’s office before confirming the diagnosis of hypertension.

You must confirm blood pressure diagnosis only after the blood pressures are consistently high many times at different days. If diagnosed with hypertension, before you start your blood pressure treatment, you need to know your cause of high blood pressure.

Gestational hypertension is pregnancy induces high blood pressure. Thus, if you are pregnant, then check your blood pressure at your 20th week of pregnancy. If you are hypertension during pregnancy, then you should manage your blood pressure correctly for you and your baby’s health.

How can you lower your blood pressure?

  1. If you are more concern about your good health and ready to put consistent effort, then the best option is the lifestyle changes to lower blood pressure. Proper diet and exercise help bring back your blood pressure to a healthy range.
  2. If you are looking for a fast fix to your high blood pressure, your option is blood pressure medications. Learn, what are high blood pressure medications? Which one is suitable for you? How does it work, dosage, and its side effects?
  3. If you are looking for a natural way to lower your blood pressure. Learn, five natural blood pressure treatments; they are herbs, yoga, acupressure, and reflexology

It is necessary to keep track of your blood pressure levels to avoid any hypertension complications, thus advisable for home blood pressure monitoring.