BP Checking Machine at home

Your blood pressure changes from hour to hour, sometimes even minute to minute. Standing up from a chair, watching an exciting show on television, eating a meal, listening to soothing music, being stressed — even the time of day — influence 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 (Hypertension, July 2008). 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 tells the whole story, and 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 trekking to and 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. Timely feedback helps. Instead of a getting a blood-pressure reading once every few months under unusual conditions (in a doctor's office), you can get a reading every week or so at home. 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 get better — or worse. Measuring it at home offers vital information about 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. Checking your pressure at home and acting on the results can help you join the "in" crowd who do. 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 (Journal of the American Medical Association, June 25, 2008).

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.

Who needs to do this?

The new recommendation says home monitoring should be done by most people "with known or suspected hypertension." That includes the whopping 73 million Americans with high blood pressure. It also includes the millions more with type 2 diabetes or chronic kidney disease, who are at high risk for developing high blood pressure. Women who become pregnant should consider checking their blood pressure at home, since high blood pressure is a common, and problematic, side effect of pregnancy. You might also think about it if you are seriously overweight, if you smoke, or if high blood pressure runs in your family.

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. Models that store readings for a week or two can simplify record keeping. The AHA doesn't recommend wrist or finger home blood pressure monitors.

Consumer Reports occasionally reviews home blood pressure monitors. Its last such review was in September 2011. The ReliOn HEM-741CREL got a "best buy" rating.