My GP asks for patients to take their blood pressure on a Monday morning and then to repeat the reading just one minute later, with that 'two readings' method being repeated on each Monday morning, Monday evening, Friday morning and Friday evening for a four week period.
Here's the first bit of the last set of readings that I sent to him:
https://ibb.co/NTrT1YP
You'll see that there are
some very high readings in there but the majority have a 'normal' diastolic figure (of around 80) and a 'not wildly high' systolic figure (in the 130s or 140s). My GP seemed happy enough with those and found no reason to change my medication.
So it's overall patterns that GPs really like to know about, rather than specific figures at any particular moment.