Mechanics of Blood Pressure
It all starts with your heart which pumps blood out of the heart into your body’s arteries. These large arteries taper down into smaller vessels called arterioles. These arterioles then taper into even smaller vessels called capillaries. It is at the capillary level that your blood exchanges the oxygen and nutrients it carries in exchange for the cell’s waste products such as carbon dioxide and toxins. This blood then flows out of the capillaries into your veins returning your blood to the heart.
As your heart pumps blood through the lungs the carbon dioxide is exchanged for oxygen. And, as your blood is pumped through the liver, the liver removes most of your toxins.
Given this closed pumping system, there are two main factors that can contribute to changes in your blood pressure:
o Strength of Heart Contraction – Your heart acts as a pump. As your heart contracts it squeezes out the blood into its various chambers or into the large arteries leaving the heart. The strength of your heart’s contraction will determine the head force of the blood as it leaves the heart.
o Resistance to Blood Flow – Once your blood leaves the heart it’s going to meet resistance. This resistance can be from arteries that have aged and lost some of their elasticity. Or, the resistance can come from plaque and other fatty deposits that change the interior shape of the arteries and arterioles. Certain nerve impulses can trigger the endothelial cells that line the interior of your blood vessels to release nitric oxide.
Nitric oxide is the main signaling molecule of the cardiovascular system and determines how much a blood vessel will dilate (become larger) or contract (become smaller). Finally, resistance is going to occur at the capillary level. If the capillary beds are restricted then resistance to blood flow will increase. If the capillary beds are open and flowing then resistance to blood flow will be minimized.
As you can see there are multiple factors that affect your blood pressure. Although heart strength is one of them, most of the factors that affect this area occur once your blood leaves the heart. This is why in 90 to 95 percent of high blood pressure cases the cause is unknown. The remaining 5 to 10 percent of cases usually have a known cause which could be:
o A kidney abnormality.
o A structural abnormality of the aorta which is the large artery leaving the heart.
o A narrowing of certain arteries from a specific disease.
Most of these problems can be corrected. The challenge is dealing with the remaining 90 to 95 percent of these cases.
When you go to the doctor’s office or hospital, one of the first things done by a nurse or health practitioner is to take your blood pressure. They wrap a large cuff around the upper part of your arm. Then they manually pump air pressure into the cuff causing it to expand which puts pressure on your arm. Eventually the pressure in the cuff is greater than the pressure in your arm’s artery. This then stops blood flow.
The next step is for the health practitioner to place the bell of their stethoscope over the artery in your arm and begin to slowly release the pressure in the cuff. They are listening for two sounds. When your blood pressure is greater than the pressure in the cuff, then your blood will again pulse through your arm’s artery. This makes a sound and this first sound is called your systolic pressure. When the sound finally goes away this final sound is called your diastolic pressure.
Your blood pressure is recorded as two numbers such as 110/70 mm Hg (millimeters of mercury). The systolic pressure is the first and larger number. It represents the pressure generated by your heart when it contracts to pump blood out of the heart into your body.
The second and smaller number is the diastolic pressure. This is the pressure of the blood in your arteries when your heart is refilling itself just before it contracts again. It is the diastolic pressure that enables your blood to continue to circulate through your body.
The medical community has determined a normal range for both these systolic and diastolic pressures. Anything above this normal range is considered either “prehypertension” or “hypertension.” The range is as follows:
o Normal Blood Pressure – Any thing below 120/80 mm Hg
o Prehypertension – If your systolic pressure is 120 to 139, or your diastolic pressure is 80 to 89, or both
o High Blood Pressure (Hypertension) – If your systolic pressure is 140 or higher and/or your diastolic pressure is 90 or higher
It is estimated that 72 million Americans have high blood pressure which means 1 in 3 adults have this “Silent Killer!” It is called this because there usually are no symptoms. This means that most who have high blood pressure don’t even know it.
Now you might think if there are no symptoms, then what harm can it be to your body. Here is a list of the potential damage it can do if left unchecked:
o Increased risk for heart disease
o Increased risk for heart attack
o Increased risk for congestive heart failure
o Number one cause of stroke
o Increased risk for kidney failure
o Increased risk for peripheral artery disease
o Increased risk for aortic aneurysms
o Increased potential for eye damage with loss of vision
That’s quite a list of potential life-threatening health issues. You need to pay attention to your blood pressure and find ways to reduce your risk for this silent killer.
If you don’t know what your blood pressure numbers are, then make it a priority to visit your pharmacist, local clinic or doctor’s office in the next seven days and have a qualified person take your systolic and diastolic readings. It is your first step in addressing this potential killer especially if you want to slow down the aging process and improve your overall health and well being. Until next time, may we both age youthfully!