- Use a validated upper-arm cuff that fits your arm.
- Sit quietly for five minutes first: back supported, feet flat, legs uncrossed, arm resting on a table at heart level, bladder empty.
- No caffeine, exercise or smoking in the previous half hour, and no talking during the reading.
- Take three readings a minute apart and type all three; VT sets the first aside and averages the other two (readings synced from a cuff are used as they are).
- Measure in the morning before food, drink and medicines, and again in the evening.
- For a baseline or a check, measure morning and evening for seven days; the guidelines read the average without the first day.
- Otherwise once a week, at the same time, on the same arm.
- Sync or type every reading.
Why an upper-arm cuff, and why the size matters
The validated-device lists exist because many cuffs on sale have never been tested against a reference, and a cuff that has passed the international protocol agrees with it to within a few mm Hg on average. The cuff's inflatable bladder has to match the arm: one that is too small for the arm reads high, one too large reads low, and the arm circumference printed on the box is the only thing that tells you which you need. Wrist cuffs are harder to hold at heart level and read differently; the pressure estimates some watches and rings offer are a different measurement again; VT reads whatever blood pressure reaches Apple Health or Health Connect and cannot tell a cuff from a watch, so connect only an upper-arm cuff.
Why five minutes, and why no talking
Pressure settles over several minutes after you sit down, talking raises it while you talk, a full bladder raises it, and crossed legs raise it. The first reading of a session runs higher than the second in most people, which is why the measurement guidelines ask for two or three readings and discard the first, and why VT does the same (Stergiou 2021).
Why morning and evening
Pressure is lowest asleep, rises steeply on waking and often runs higher again in the evening. The morning reading, before food and before any medicine, is the one most guidelines rest on and the one that shows the end of a medicine's day; the evening reading shows the other end. Log both; VT averages the day's readings into one figure.
Why seven days, and why weekly after
A week of paired readings, with the first day dropped, is the measurement guidelines' schedule for a home average, and it is the one to do at the start, after any change (a new medicine, a new plan, a weight change of a few kilograms), and whenever your doctor asks for a check. Between blocks, a weekly reading keeps the arteries area of the Vitality Score counting in full, because a reading counts in full for seven days and is still used for fourteen; from 50, a daily reading gives a daily value of the pressure indices and a weekly reading gives a weekly one, each compared with the average of your previous seven readings.
Why the same arm
Pressure differs between arms in many people, by 10 mm Hg or more in some. Measure both arms once at the start, keep the higher one, and stay with it; a series that alternates arms is two series.
What VT does with the readings
Every reading is stored with its systolic, diastolic and time, the pulse when you type it, and the app it came from when it is synced. The day's figure is the average of the readings kept. It feeds the arteries area of the Vitality Score at any age, and from 50 it becomes pulse pressure, mean arterial pressure and fractional pulse pressure, each compared with the average of your previous seven readings. Beside each reading VT shows its category, from Optimal to Very high, colored amber from 130/85 and red from 140/90 mm Hg; these describe the reading, not a diagnosis. The European home-measurement guideline's reference for a raised home average is 135/85 mm Hg; if your average sits above it, take your readings to your GP.
| Situation | Schedule | Note | | --- | --- | --- | | Starting out, or a baseline | Morning and evening for 7 days | First day dropped; the average of the rest is the baseline | | Ongoing | Once a week, same time, same arm | Keeps the Vitality Score's arteries area fresh | | After a change: a new medicine, a new plan, a weight change of a few kilograms | A 7-day block, then weekly | Log the change as an intervention so the step has its explanation | | From 50, the pressure indices | Daily if you want a daily value | Each reading compared with the average of your previous seven; under 2 percent is stable | | Unwell, traveling, after alcohol or a hard session | Skip it | A day marked sick is not yet left out of the blood-pressure figures |
Vitality Tracker describes and tracks your measures against your own history, for general wellness and for discussion with a health professional. It does not diagnose, predict or monitor any disease; what a reading means for you is a conversation with your doctor.
Sources
- Stergiou GS, et al. 2021 European Society of Hypertension practice guidelines for office and out-of-office blood pressure measurement. J Hypertens 2021;39:1293–302. doi:10.1097/HJH.0000000000002843 (record only; the schedule, the discard rule and the home reference are the guideline's)
- Lewington S, et al. Lancet 2002;360:1903–13. doi:10.1016/S0140-6736(02)11911-811911-8>)
- Vitality Tracker, How it works (the blood-pressure measures, the consultation suggestion); Knowledge Base brief, how-to 5.