How Blood Pressure Is Measured

The protocol

• One upper-arm cuff monitor for the whole year
• Seated, feet flat, back supported, arm resting at heart height
• At least a few minutes of quiet sitting before the first reading
• Same arm each time
• Systolic, diastolic and pulse are recorded as displayed, with the date

Where readings are repeated, the second is the one recorded, because the first reading of a session is commonly the highest.

Why this is worth tracking through a fasting year

Blood pressure responds to fluid balance, sodium intake, sleep, stress and caffeine — all of which a fasting day touches. A drop on a fasting day is not automatically a health improvement; it may simply be a lower circulating volume. That is why the reading is published with the day's fasting status rather than as a standalone number.

Known limitations

Home cuffs are not clinic devices. The value here is in a long series taken the same way, not in the accuracy of any single measurement. Anything that looks clinically concerning is repeated and taken to a clinician rather than interpreted on this site.

What this measurement cannot tell you

A single reading is close to meaningless on its own. What matters is the shape of the series across a year, read alongside the fasting schedule, sleep, training and the notes for that week. Nothing on this site is presented as evidence that fasting caused a change: this is one person, with no control condition, and many things change over a year besides the fasting days.