Measuring Blood Pressure At Home

Your blood pressure changes from hour to hour, sometimes even minute to minute.
Standing up, watching an exciting sports event, eating a meal, even the time of day
infl uence your blood pressure. It jumps around so much that you are more likely to
get a “normal” reading if you check it at home rather than in the doctor’s office.
That idea underlies a recommendation from the American Heart Association
(AHA), American Society of Hypertension, and Preventive Cardiovascular Nurses
Association. They urge individuals with high blood pressure, or at high risk for
developing it, to become blood pressure do-it-yourselfers. There are many good
reasons to follow their advice:

Find your real blood pressure. The measurement your doctor or nurse takes is just
a just single frame from an ongoing movie. In some individuals, that snapshot is an
excellent approximation of their usual blood pressure. In others, it isn’t. Up to 20%
of people diagnosed with high blood pressure have white-coat hypertension. This
is a temporary spike in blood pressure brought on by the stress of seeing a doctor.
Still others have what’s called masked hypertension — normal blood pressure in the
doctor’s office but high blood pressure everywhere else.

Improve your control. People who check their blood pressure at home tend to be
more successful at keeping it under control. Instead of a getting a blood-pressure
reading once every few months in a doctor’s office, you can get a reading every week
or so at home. Being more involved by taking the measurements yourself also helps.
People who actively participate in their care generally do better than those who take
a hands-off, let-the-doctor-do-it approach.
Track your progress. You can’t feel your blood pressure improve — or get
worse. Measuring it at home can tell you whether your lifestyle changes and the
medications you are taking are having their desired effects.
Save time and medications. Monitoring your blood pressure at home may mean
fewer trips to the doctor’s office. If you have white-coat hypertension, it may also
mean taking fewer, or no, blood pressure medicines.

Run with the right crowd. Of every 100 people with high blood pressure, 70 or
more don’t have it under control. A study shows that people who checked their
blood pressure at home and e-mailed the results to a pharmacist who offered advice
were far more likely to keep their blood pressure in check than those who merely
measured it at home or those who had it taken by a doctor every now and then.
Key Points
• If you have high blood pressure, it’s a good idea to check your blood pressure at home.
• Use an automatic monitor with a cuff that fits around your arm and that keeps
track of your readings.
• Check your blood pressure once in the morning and once in the evening for a
week, then one or two days a month after that.
Picking the Right Machine
There are dozens of different home blood pressure monitors on the market. For best
accuracy and ease of use, buy one with a cuff for the upper arm that automatically
inflates and that automatically records the pressure. The AHA doesn’t recommend
wrist or finger home blood pressure monitors. The September 2008 issue of
Consumer Reports compares home blood pressure and blood sugar monitors.
Do it Right

When it comes to measuring blood pressure, technique matters. Doing it wrong can
give you a reading that’s too high or too low. (To see a brief video on using a home
blood pressure monitor, visit
www.health.harvard.edu/128

There are two things to do before you
start. First, check your machine against
the one in your doctor’s office. Second,
make sure you have the right size cuff —
the inflatable part should encircle at least
80% of your upper arm.
When you first start to check your blood
pressure at home, measure it early in the
morning, before you have taken your
blood pressure pills, and again in the
evening, every day for a week. After that, follow the plan your doctor recommends,
or check it one or two days a month. Each time you take a reading:
• Avoid caffeinated or alcoholic beverages, and don’t smoke, during the 30 minutes
before the test.
• Sit quietly for five minutes with your back supported and feet on the floor.
• When making the measurement, support your arm so your elbow is at the level of
your heart.
• Push your sleeves out of the way and wrap the cuff over bare skin. Measure your
blood pressure according to the machine’s instructions. Leave the deflated cuff in
place, wait a minute, then take a second reading. If the readings are close, average
them. If not, repeat again and average the three readings.
• Don’t panic if a reading is high. Relax for a few minutes and try again.
• Keep a record of your blood pressure readings and the time of day they are made.
Checking blood pressure at home won’t cure hypertension, but it will help control
the most common cause of stroke and a big contributor to heart attack, heart failure,
and premature death.
For more information on diagnosing and treating high blood pressure, order our
Special Health Report, Hypertension: Controlling the ‘silent killer,’ at
www.health.harvard.edu/HT
 
Sal Casano, Ph.D. RN, FCN

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