Blood Pressure — A Patient Primer
So your family physician has told you that your blood pressure is borderline or high? What does that mean anyway? What is blood pressure and why does it matter? Read on for a beginner’s guide.
What is Blood Pressure?
Your heart pumps blood to the rest of the body to distribute nutrients and pick up waste. The pump (your heart) is hooked up to your organs/tissues by blood vessels (arteries and veins). Blood pressure is a measure of the pressure in these vessels.
The systolic blood pressure (colloquially known as the top number) is the pressure when your heart pumps. The diastolic pressure (the bottom number) is the pressure when your heart relaxes. Pressure is commonly measured in mmHg (millimeters mercury) by a sphygmomanometer (Blood pressure machine).
High blood pressure (hypertension) is defined as a pressure that is consistently higher than 140/90 mmHG. Normal blood pressure is consistently less than 120/80 mmHG. Levels consistently in between are considered pre-hypertension.
So why does an increased pressure matter anyway?
Imagine being a tiny little blood vessel in a kidney of a person with high blood pressure. With each pump of the heart, your walls would experience a force (pressure) higher than normal. Chronic exposure to these pressures over years could end up permanently damaging your walls. Damage to your walls could lead to a problem with delivering nutrients to the kidney you’re supplying. This damage can also lead to build up of plaque along your walls. All this can lead to narrowed and less elastic arteries. Ultimately, all this could lead to kidney disease. A similar process in other organs could contribute or lead to diseases such as dementia, coronary artery disease, heart failure, stroke and eye disease.
The reason for treating high blood pressure is not to treat the number but to limit the development or progression of diseases like those mentioned above.
Measuring Blood Pressure
It is important that when your blood pressure is being measured, it is being measured properly. Measuring blood pressure inappropriately can lead to overestimation of blood pressure and a false diagnosis of hypertension. When your doctor is measuring your blood pressure, you need to be in a resting and relaxed state (ideally, sitting with no talking for 5 minutes prior to measurement). Rushing to your appointment after a stressful day at work is probably not the best time to get your blood pressure measured. Your bladder should be empty and you should refrain from smoking or drinking caffeinated beverages for at least a half hour before the measurement. Your physician should be cognisant of using the right sized cuff and appropriate positioning (legs uncrossed, arm at heart level).
One high reading does not mean a diagnosis of hypertension. Usually your physician will measure your blood pressure over a span of a few visits before diagnosing hypertension. In addition, you may be asked to do some blood work and an ECG to look for any evidence of co-morbidities (diabetes for example) or evidence of early signs of end organ damage (decreased kidney function, changes in your heart rhythm, protein in your urine etc.).
What causes hypertension anyway?
Hypertension can be broadly divided into two categories. Primary (or essential) hypertension does not have one clear cause. Rather it is caused by a combination of environmental or genetic factors (family history, sedentary lifestyle, smoking, stress etc.). Primary hypertension accounts for the majority of cases. Secondary hypertension is caused by an underlying, possibly correctable cause (sleep apnea, kidney disease or hormonal diseases for example). Secondary hypertension accounts for maybe 5–10% of all cases. Secondary hypertension can often be treated by treating the underlying cause. This discussion is primarily focussing on essential hypertension.
A diagnosis of hypertension has been established, what now?
Unless your blood pressure is dangerously high, there are already signs of end organ damage or you have multiple co-morbidities, your physician will not likely jump to treating you with a medication. A good physician will explain the diagnosis, discuss its inherent risks and then move to a discussion revolving around lifestyle changes that can be made to treat your hypertension. I will not be discussing medications to treat blood pressure here but if one is suggested, ensure your decision is an informed one.
Lifestyle management
There are a number of steps in terms of lifestyle that can be take in order to improve blood pressure. www.hypertension.ca has some great tips which are summarized below.
Limiting salt intake will help reduce your blood pressure. Try to aim for less than 2000 mg of sodium (5 grams of salt) per day. When buying packaged foods, aim for a serving that has less than or equal to 5% of your daily intake.
Quitting smoking will lead to a number of significant health benefits in addition to helping lower your blood pressure. Your family doctor can provide you with a number of resources and outline options available to you to aid smoking cessation.
Stress is a significant contributor to high blood pressure and working on limiting stress and improving stress management can go a long way in aiding blood pressure reduction.
Being physically active is an excellent way to maintain or improve health and treat or limit the progression of diseases such as hypertension. Great tips and guidelines regarding physical activity can be found here.
Eating a well-balanced diet, limiting alcohol consumption and maintaining a healthy body weight can all help you improve your blood pressure. The DASH diet (Dietary Approach to Stop Hypertension) has been shown to reduce blood pressure. More details on it can be found here. If you are struggling with weight management, I suggest you start here and of course open a discussion with your family doctor.
Hypertension is an increasingly common condition and it behooves all of us to increase our education around its diagnosis, risks and treatment. Any questions? Ask your family doctor, she’ll be glad to help!
