- Dr. Mike Purdon
Understanding blood pressure: the basics
Updated: Apr 11, 2019
You are probably reading this because we noticed that your blood pressure was elevated. We hope that you find this information and the links useful in understanding why your blood pressure matters to us.
I like how the Mayo Clinic puts it on their patient information website:
“High blood pressure is a common condition in which the long-term force of the blood against your artery walls is high enough that it may eventually cause health problems, such as heart disease.
Blood pressure is determined both by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries. The more blood your heart pumps and the narrower your arteries, the higher your blood pressure.
You can have high blood pressure (hypertension) for years without any symptoms. Even without symptoms, damage to blood vessels and your heart continues and can be detected. Uncontrolled high blood pressure increases your risk of serious health problems, including heart attack and stroke.
High blood pressure generally develops over many years, and it affects nearly everyone eventually. Fortunately, high blood pressure can be easily detected. And once you know you have high blood pressure, you can work with your doctor to control it.”
This seems pretty simple, but there are many ways in which diagnosing and treating blood pressure problems can be confusing. Let’s outline a few of them by reviewing comments and questions we often hear in the office:
“The office is a terrible place to measure my blood pressure. I think I have white coat hypertension.” This may be true, even though most of us don’t wear white coats anymore. In fact, I always say that “no one comes to the office to relax” and measuring blood pressure at a place where people are often stressed, tired or unwell is likely to be misleading. We know that your blood pressure may be very different at home or at your work, or while you are exercising, than it is in our office. Rarely, blood pressure can even be better in the office than outside, so it is important for us to get some readings in other settings. Experts suggest that the very best way to measure your blood pressure is take multiple readings outside the office, using a monitor that can be worn for 24 hours, but many of our patients prefer to use a machine at home or at the pharmacy to collect multiple readings for us to review. A sample log can be found here. If we have sent you to this page, you can really help us by completing one of these logs a couple of times per year for us to review.
“My blood pressure is always changing and no two readings ever seem to be the same.” Measuring blood pressure is a little like monitoring the speed of your car with the speedometer. As you drive your car’s speed will vary from moment to moment, just like your blood pressure does. There are times when speed will be high and when it will be low and your blood pressure varies like this too. It is really important to us to know what the high numbers are and what the low numbers are and we need to get a sense of your average blood pressure as well. If we have recommended that you start monitoring your blood pressure you will see lots of variation in the readings, but over time we will get a sense of the average blood pressure and the highs and lows. This will guide us in helping you to reduce risk.
“Doctors seem to use different standards for defining high blood pressure in different people.” This is true. For example, if you have diabetes, kidney disease, heart disease, or if you have had a stroke or mini stroke, we will try to help you get your blood pressure especially low to protect your organs from further damage. We will also want to be really careful that your blood pressure doesn’t get too low as this can cause symptoms as well. For younger, healthier patients, we can allow blood pressure to run a little higher. It is really important to talk to your doctor about what the best average blood pressure is for you.
“Can’t I just cut back on salt and exercise more to get my blood pressure down?” Exercise, diet and weight control are all important in keeping blood pressure under control. Many patients can avoid medication altogether by getting fit, dropping weight and changing their diets. Sometimes, despite our best efforts, these measures aren’t enough though. You may have heard of the DASH diet, and this seems to be particularly helpful for patients with high blood pressure. We really like the Mayo Clinic’s guidelines on blood pressure and exercise. Please talk to us before you start a diet or exercise program to make sure that it is safe for you.
“You said I had high blood pressure and that I needed a blood pressure pill and then you gave me a water pill.” We have lots of different types of medications that we can use in the treatment of blood pressure. One of the most commonly used medications is a diuretic, or water pill. These medications reduce fluid as well as lower blood pressure so they are often also prescribed to help reduce edema or swelling as well as treat blood pressure. In fact, we will often recommend a medication that might help with other conditions that you might have so that one medicine can serve two purposes. For example, certain types of blood pressure pills can help with migraine headache or chest pain, or rapid heart beats or diabetes. It is important to understand the potential benefits of your blood pressure medication, beyond just reducing your blood pressure.
Hopefully this information will be helpful in better understanding blood pressure. Please let our staff know if you are interested in any of the group visits that we offer for patients with high blood pressure.
Heart and Stroke Foundation Canada