Normal Blood Pressure: It's Vital

You can't get through a trip to the doctor without having a blood pressure cuff wrapped around your arm. It doesn't matter if you were at the same office three days ago or if you are coming in for an obvious case of poison ivy - your arm will not be escaping the cuff. Someone will slap that sucker around your biceps, pump it up to give you a nice squeeze, mysteriously listen to your elbow through their stethoscope (it's weird when you think about it), and then mutter some numbers that may or may not be good. If you're lucky, you'll hear something to the effect of: "118 over 72".

Everyone knows that a normal blood pressure is essential to being healthy, but what exactly is blood pressure? What do those numbers actually tell us? Why is blood pressure important enough to be a VITAL sign? Why does everyone freak out when the numbers start to creep up, even slightly? And why, oh why, is high blood pressure associated with so many terrible things (heart attack, stroke, kidney failure, death... you know, those kinds of terrible things). 

To appreciate the importance of blood pressure, we must first understand: 1) pressure and 2) what happens in your body during a single heart beat. Don't be intimidated and stop reading. This isn't going to include crazy diagrams or calculations (it could but that's already been done). 

• Pressure: this is a word we all use and understand, but let's dissect (pun gleefully intended) the meaning as it relates to blood pressure. Pressure, in the world of physics, is a calculation based on the amount of force that is being exerted on a given area. Your blood pressure is the amount of force applied to the walls of your arteries as blood flows through them. Why two numbers? Let's talk about your heartbeat first...

• When your heart beats, it contracts, pumping blood out of your heart to circulate throughout your body. During the fraction of a second between heartbeats, your heart is relaxed and refilling with blood.The contraction phase of the heartbeat is referred to as systole and the relaxation phase is termed diastole. Hence, your systolic blood pressure (top number) is the pressure exerted on your artery walls when your heart is contracting. Your diastolic pressure (bottom number) measures the pressure while your heart is relaxed.

Now that you understand what blood pressure is measuring, it probably makes intuitive sense why high blood pressure (also called hypertension) can be so damaging to your body. First of all, if your blood pressure is too high, it is causing your heart to work harder than normal. Second, the increased pressure can damage your blood vessels and to organs such as your kidneys. Damage caused to your blood vessels can include tears, which are prime areas for build up of plaque, thus causing narrowing of the vessels, in turn leading to stroke or heart attack. High blood pressure can even lead to rupture of blood vessels, as occurs in an aneurysm (basically the pressure can cause an artery to explode... BAD NEWS). 

Unlike low blood pressure, which is symptomatic (dizziness, fainting, etc), high blood pressure is usually asymptomatic until it causes one of the aforementioned terrible things to happen. This is why it is incredibly important for high blood pressure to be treated as soon as possible. Click here for more information on prevention and treatment of high blood pressure. 

So, next time you get your blood pressure measured, don't think "oh not this again" but be grateful for the opportunity to catch high blood pressure before it gets out of control. It's vital!