Virginia -

The "three times" check of BP is, if I interpret who recommends it and who doesn't, primarily for home use where you may not have a controlled routine, and may not take the time to "settle down" from varying levels of exercise.

It also might be advisable in an emergency room situation, or in a really crowded clinic where there's lots of hustle and bustle and consistent conditions are harder to provide.

Some practitioners are careful to control conditions so that patients are always put in a quiet place for a reasonable time, and are always checked under "standard conditions" so that multiple readings are not really needed, and if consistent conditions are assured even a single reading can probably be consistently interpreted.

Some MDs make a practice of having a nurse do the BP check simply because people are less prone to "white coat syndrome" that elevates BP for a few minutes after "the doc" comes in. When I was a lot younger, I encountered one or two very cute nurses that I'm sure must have momentarily added about 20mm to my readings; but I've found recently that they seem to have been specially trained to "avoid stimulation" of that sort - or maybe they just know not to send the cute ones in for my exams (dammit!).

One factor in the BP reading that has always slightly bothered me is that the "old fashioned" sphygmomonometer and stethoscope method depends on the acuity of hearing of the examiner. The systolic pressure is the highest pressure at which the examiner hears a pulse, and the diastolic is the lowest. If the one taking the readings can't hear the pulse, the reading is wrong (and I've had nurses whip the cuff off when I could still "hear" the pulse without a stethoscope by watching the mercury column still pulsating). It's for this reason that I'd suggest, if you wish to get a home-use monitor, an automatic one may give you more consistent and reliable readings than the slightly cheaper ones that make you try to use a (very cheap) stethoscope. And those with an "arm cuff" are definitely more accurate and reliable than the wrist type if you're only going to have one.

John