Blood Pressure, the real story


I had my annual medical the other day and my Blood Pressure (usually denoted by the letters BP) was reported as being marginally high at 145/75. The computer wondered if this was “Hypertension” and the standard response is to check again in two weeks.

Now that’s not a bad plan, but if your doctor tells you that you have hypertension on just one reading – don’t believe him (or her).

So how do you find out if your BP is too high? Quite simply by repeated measurements. Just as one swallow doesn’t make a summer, one elevated reading does not necessarily mean Hypertension. In my own case, I had been rushing prior to the annual medical testing, and the repeat measurement one week later was 134/76.

You see, Blood Pressure is a dynamic situation. Lying down you can have one BP. Get almost run over by a baht bus and you have another much higher BP. Blood pressure tends to be higher in the morning and lower at night. Stress, smoking, eating, exercise, cold, pain, noise, medications, and even talking can affect it. The single elevated reading does not immediately mean you have high blood pressure. In fact, the average of several repeated measurements throughout the day would be a more accurate picture of what is going on than a single reading, but quite frankly, you do not have to go to that extreme.

As part of the routine in most good hospitals and clinics is the measurement of your blood pressure. You should get this done at least twice a year. Rising or elevated readings do mean you should get medical advice.

So why is BP important? Because if you don’t you don’t have BP you are definitely dead! However, if your BP is too high, it can mean you could be claiming early on your life insurance policy – or your relatives will, on your behalf.

High BP is otherwise known as the “silent killer” as there are very few symptoms of the increase in blood pressure, until a vessel bursts somewhere, generally catastrophically! The good thing is you are dead within minutes, so you won’t linger.

Blood Pressure is needed to keep all the organs of the body supplied with oxygen. This is done by the red blood cells which carry the oxygen, with the pump to drive the system being the heart. The tubes from the heart heading outbound are the arteries, and those returning the blood to the heart are the veins.

This heart-arteries-veins-heart system is a “closed” circuit. In other words, no leaks, otherwise you would be continually losing the life-preserving blood, but to make it go around, there has to be a pumping pressure (just like the oil pump in your car).

The heart squeezes the blood inside itself and pumps it out into the arteries. This squeezing pressure is called the Systolic, and is the upper number quoted when we measure your blood pressure.

After the squeeze, the heart relaxes to allow the blood to fill the chamber, ready for the next squeeze. The pressure does not return to zero, because there has to be some pressure to refill the chamber. This resting or ambient pressure is the lower number quoted and is called the Diastolic. BP is then typically quoted as 120/70, being 120 (systolic) / 70 (diastolic). The actual pressure number is measured in a millimeters of mercury scale.

So what is your correct BP? The following table shows the categories of BP measurements.

Optimal: less than 120/80
Normal: less than 130/80
High-normal: 130–139/85–89

High blood pressure (hypertension):
Stage 1: 140–159/90–99
Stage 2: 160–179/100–109
Stage 3: 180 or higher/110 or higher

The problem with running at high pressure is that the heart is having to work harder, and therefore may be subject to heart failure. The arteries are also subjected to higher pressures than they were designed to cope with and can burst, making the risk of stroke so much higher. Other organs don’t like working at the high pressures either, and kidneys, in particular, can go into failure mode.

No, if you really have hypertension, get it treated – but remember to have repeated measurements done.