Blood Pressure, Hypertension & The Numbers Game
Jun 7, 2016
By Barret Procyshyn
Everyone understands hypertension, or elevated blood pressure readings can be concerning. It's almost a given; if you show up in a nursing station, walk in clinic, doctor's office or emergency room, the first test to be taken is blood pressure. A cuff gets put on your arm and the machine generates two numbers. What can be a little confusing for some is what those two numbers are should ideally read and what complications can arise if your numbers are consistently elevated.
The top number in a blood pressure reading is the systolic pressure. This number, which will always be the highest of the two, measures the blood pressure in arteries when the heart beats and the heart muscle contracts. If we think of the heart and blood vessels like a pump and plumbing pipes, systolic pressure is measured in the pipes as the pump is in the process of pushing the fluid through them.
The bottom number in a measurement, called diastolic pressure, is the lower of the two numbers. It measures the pressure in the arteries between heartbeats. This is when heart muscle is resting between beats and refilling with blood. Continuing with an analogy, the pump would be taking a break when measuring the fluid in the pipes.
While both numbers are important, we usually pay more attention to the top number as a major risk factor for cardiovascular disease. Unfortunately as we age, most people will see their systolic blood pressure rise, due to increasing stiffness of large arteries, potential build-up of plaque, and increased incidence of heart and vascular disease. Again, using the plumbing analogy if the pipes cannot expand or become narrower, the pressure goes up.
So why all the fuss about the numbers, especially when you might not feel any effects of hypertension? Then the pressure in pipes becomes too high something will burst. Over 1.6 million Canadians have heart disease and one person dies from it every seven minutes. More than 350 000 will be hospitalized for heart disease or stroke and over 400 000 have a stroke induced disability. If you take one thing from this discussion - please remember consistently high blood pressure numbers are a concern and do matter to your health.
Blood pressure is considered to be normal when the systolic number is less than 120, while the diastolic pressure is less than 80. While there are exceptions, usually a low blood pressure is good. If your numbers hover slightly over 120/80, it is more than likely not a problem. The 2016 Hypertension Canada guidelines list any pressure less than 140/90 as a treatment target for someone who has been previously diagnosed with hypertension. This means for someone on blood pressure treatment, anything under 140/90 is perfectly fine. However, if you have deemed a high risk patient due to previous cardiac events, strong family history or have other chronic diseases your systolic target is anything less than 120. If you are one of the approximately 100 000 people in Manitoba who have diabetes your target is recommended to be less than 130/80.
When we talk about the numbers we now do not talk about one time readings, for the simple fact that one blood pressure is often not the normal blood pressure. In fact to be diagnosed with hypertension there has to be a series of consistently high readings. If an elevated reading is first noticed at home, a physician office or pharmacy, an additional doctor's appointment should be booked to do another reading. If that reading is greater than 180/10, hypertension can be diagnosed instantly. If the reading is less than 140/90 and you do not have diabetes, hypertension is not diagnosed.
If the reading is over 140, one of two further options is required. Option 1 is to do a home blood pressure series. This involves two readings taken in both the morning and evening for 7 days. The average of the last 6 days is used. If the average is higher than 135/85 hypertension is diagnosed.
Option 2, the preferred option, is to do a 24 hour ambulatory blood pressure monitoring. This involves wearing a portable blood pressure machine for 14 hours, which automatically tests pressure throughout the day. If the average of these readings is greater than 130/80 hypertension can be diagnosed. If you are a customer at the Dauphin Clinic Pharmacy and your doctor prescribes a 24 hour blood pressure test, we have the devices available to do so. We also have automated blood pressure machines available to our customers to loan or to purchase.
Look for the article next week in the Parkland Shopper, discussing treatment of Hypertension including the importance of lifestyle modifications.