@bolso1 Good question. For most of us, as we relax and our mind wanders to other things while doing a repeated task such as three measurements over about five minutes of one's own blood pressure, our nervous system calms, our Vagus nerve kicks in, and each successive reading 'should' (might not) fall naturally to a low. That low is what your baseline is, or thereabouts. A first reading is likely to be rushed, will be the first after recent stresses of a kind (even if just trying to remember where your blood pressure cuff is stored), and will in all probability be th highest of the three, so above a computed average if you were to take that figure. On the other hand, the lowest of the three is more likely to be closer to your real base BP, the kind you'd have seated while driving on a long trip, or seated on a bus on a route you take daily, or when watching TV in your own home. It's at the doctor's office, walking briskly, dealing with a tough problem or a contrary personality you know in a colleague that are the typical transient instances that spike BP. Obviously, spiked BPs throughout a typical day should not be taken as the veridical measure of one's BP that needs treatment.

This is why I coach people to take both their heart rate and BP first thing before sitting up in bed when they awaken. Moving slowly, and ideally using a smart watch capable of those measurements, take one or more of each, trying hard to keep calm and to not anticipate or to begin thinking of the day's chores or problems....which can cause arousal of the sympathetic nervous system, which in turn will raise the BP. It is those first-thing measurements that tell you of your overall heart health. If the measurements show elevated results over, yes, THAT average, one taken month after month, it indicates that there may be something at play that you should deal with, whether too much heart activity the previous day (a hard hike or run), too little sleep, poor quality sleep, a virus, etc.