How to keep a blood pressure log your doctor can use

Write down every reading with its date, its time, both numbers and your pulse. Measure twice a day for a week, two readings each time, one minute apart. Your doctor reads the average of days two to seven, not any single line, so the log is worth more than the best reading in it.

What to write in each line

One line is one reading: the date, the time, the systolic number over the diastolic number, the pulse, and a word of context when something was unusual, such as a missed dose, a late night or a walk up the stairs before you sat down.

The American Heart Association asks you to take two readings one minute apart each time and record both. Both go in the log; do not keep the lower one and drop the other. The printable blood pressure log has a line for each of the two, morning and evening, for seven days.

How many readings make a log

NICE NG136 sets the routine doctors use to confirm high blood pressure at home: two consecutive readings at least one minute apart, seated, recorded twice a day, ideally in the morning and the evening, for at least four days and ideally seven. That is 28 readings over a full week, or 16 over the shortest week NICE accepts.

Take them at the same times every day. A morning reading and an evening reading tell the doctor different things, and a log that mixes noon one day with midnight the next hides the pattern. How to check blood pressure at home covers the routine around each reading.

Why the first day does not count

NICE NG136 drops the readings from the first day and averages everything after it. Keep the first day in the log, mark it as day one, and leave it out of the sum. On the printable sheet the average row says so; in the app the week’s average is worked out for you.

What the average means

Average the systolic numbers and the diastolic numbers separately, days two to seven. The average blood pressure calculator does the arithmetic and names the range.

At home, ESC 2024 draws hypertension at 135/85 or higher and calls a reading below 120/70 non-elevated; the band between is elevated. NICE NG136 confirms a diagnosis when a clinic reading of 140/90 or higher meets a home average of 135/85 or higher, which is why the doctor wants the week, not one number. For a single reading, the blood pressure calculator shows the range and the next step.

A single high reading is not an immediate cause for alarm, as the American Heart Association puts it. Log it, sit for a minute, measure again and log that too.

Paper, spreadsheet or app

A printed sheet works for one week. It fits the columns the doctor reads, it goes in a bag, and it needs nothing but a pen. Print the blood pressure log as a page or download it as a PDF.

A spreadsheet works for longer. It needs a column for each number, a formula for the average that skips the first day, and the discipline to open it twice a day. Most people who ask how to build a log in Excel want the average without the formula.

The app keeps the log without either. BP Diary records each cuff reading with its time, adds a note when you want one, shows the average for the last week, month or three months, and prints the report a doctor asks for. On days without a cuff nearby it estimates a reading from your camera, calibrated against your cuff; the cuff readings stay the ones that count.

Bringing the log to the appointment

Bring the sheet or the app’s report. MedlinePlus says it plainly: if you monitor your blood pressure at home, keep a written record and bring the results to your office visit.

Bring the cuff as well. The American Heart Association suggests taking a new monitor to the next appointment, and bringing it in once a year after that, so the doctor can compare it against the equipment in the office. A log from a cuff that reads ten points high is a week of wasted mornings.

Then keep going. The next visit compares this week’s average with the last one, and a log that continues is the one that shows whether anything changed.