DEAR DOCTOR K: My doctor told me to check my blood pressure at home, but he didn’t give me many details. Could you provide some guidance?
DEAR READER: Keeping your blood pressure in check is vital to maintaining heart health and preventing stroke. But the way most of us monitor our pressure – by trekking to the doctor’s office for occasional blood pressure checks – is far from ideal.
For one thing, it provides isolated snapshots, rather than a complete picture. What’s more, measurements at the doctor’s office can be elevated. This phenomenon is known as “white-coat hypertension,” and it may affect as many as 25 percent of people. Simply put, seeing their doctor – even me! – tends to raise the blood pressure of some people.
The flip side is “masked” high blood pressure. This is when your blood pressure looks fine in the doctor’s office but is higher at other times. Maybe some people feel more relaxed when they’re in the safety of their doctor’s office. Or perhaps their time in the doctor’s office is the only stress-free period of their day.
Several studies have shown that people who monitor their blood pressure at home have it under better control than people who do not. How does home monitoring help? More frequent, and possibly more accurate, information provides more opportunities to fine-tune your lifestyle and medications.
To measure your blood pressure at home, you’ll need a blood pressure cuff. You can buy a good one at a pharmacy or online for between $40 and $100. Get a cuff that inflates automatically, not one you have to pump up yourself. And get one that fits around your upper arm and shows the results on a large, easy-to-read display. The cuffs that fit around your wrist are less accurate.
To measure your blood pressure:
(1) Sit at a table with your arm resting comfortably on it and your feet flat on the floor. It’s easier for most right-handers to take the pressure in the left arm, and vice versa.
(2) Secure the blood pressure cuff snugly but not tightly around your bare upper arm.
(3) Rest your arm on the table in a relaxed posture, with the cuff at about the same level as your heart.
(4) Relax for a minute or two, taking slow deep breaths, and then take the first reading.
(5) Wait for at least two minutes and take another reading.
Take two measurements in the morning and two more in the evening. Take your measurements at about the same time every day. Be consistent about taking them either before or after your coffee and medications. Avoid taking the measurements right after exercising.
I have high blood pressure – fortunately, well controlled by medicine – and I keep an automatic blood pressure monitor at home and at work. (Yes, I know I’ve got the real blood pressure machine at work, but the home monitor is easier.) These help me and my own doctor keep my blood pressure under control.
This column ran originally in October 2014. Dr. Komaroff is a physician and professor at Harvard Medical School.