Measurement Week or 24-Hour Monitor: What to Log

For high blood pressure, your doctor or nurse often asks for one of two measurements: a 24-hour ambulatory monitor with a device your clinic gives you, or a measurement week at home. Both give more than a single clinic reading, and both raise the question of what you write down. The 24-hour monitor stores its values itself, while you keep only the diary your team gives you. The values of the measurement week you keep yourself, on paper or in the blood pressure program in Sam. That program turns them into a doctor report as a PDF, once a doctor has confirmed high blood pressure.

This text is general information. Which measurement fits you, and what your values mean, is decided by your doctor or nurse.

When your doctor asks for which measurement

A single reading in the clinic says little. Blood Pressure UK explains that the stress of having your blood pressure measured in the clinic can make it go up temporarily, and higher than it should. This is called the white coat effect. So doctors confirm an unusual reading with more measurements.

The 24-hour monitor shows your blood pressure through the whole day and night. That way your care team sees how it runs at night and in daily life. The measurement week is home measurement over seven days, and it is also a practical way to follow your readings regularly. Which form applies to you, and when, is your doctor's decision.

What to note during a 24-hour monitor

The device stores the blood pressure values automatically, so you do not type them in and you do not count them. What you control is your own diary, and your clinic tells you what to write in it. Follow it exactly. It often asks for these things:

• When you went to sleep and when you woke, so your team can read the night values.
• When you took your medicine.
• Any symptoms during the measuring, such as dizziness.
• Unusual activity, such as climbing stairs or sport.

When the cuff inflates, keep your arm still and relaxed. The 24-hour monitor is evaluated by your care team, and Sam does not read it.

How to run a measurement week at home

You run the measurement week with a validated monitor and a cuff that fits (NICE says blood pressure devices should be validated). The technique matters as much as the device:

• Measure for about seven days (NICE says at least four, ideally seven), morning and evening, at about the same times. Your clinic may ignore the first day's readings.
• Take two readings, about one minute apart, and keep both.
• Sit upright with your back supported and both feet flat on the floor.
• Keep your arm so the cuff sits at heart level.
• Rest quietly for about five minutes first, and do not talk or move while it measures.
• For about 30 minutes before, avoid caffeine, smoking and exercise, and empty your bladder.

Ask your team whether these same rules apply to your week, because instructions differ. The NHS says to take a reading, note the numbers, wait about a minute, then do it again, usually twice a day. For connecting a device and getting values into Apple Health, see blood pressure monitor: Apple Health connect. The blood pressure category calculator shows European (ESC/ESH) and US (AHA/ACC) bands for clinic measurements. The NHS uses 140/90 in clinic and 135/85 at home. It is not a self-diagnosis.

What to write down in the measurement week

Note every value right away, not later from memory. A full line includes:

• The date and the time.
• Both numbers, exactly as the device shows them.
• What came before: caffeine, alcohol, stress, salty food, sport or poor sleep. A keyword is enough.
• How you felt.
• Whether you had already taken your blood pressure medicine, if any is prescribed.

Write down values you do not like too. Your list is for documentation, not for judging yourself. Which values apply to you is decided by your doctor. For more on the usual fields, see blood pressure log: print or app. Symptoms without a direct link to a reading belong in the symptom diary. If a family member wants to follow along, the Sam for family page shows how helpers can stay in the picture.

What you take to the appointment

This depends on the measurement form. For a 24-hour monitor, you return the device and your diary, and your team reads the stored values. For a measurement week, you bring your list, on paper or as a doctor report (PDF) from Sam.

If your team prefers one form, ask before you prepare. The how often to measure blood pressure guide explains the routine, and High blood pressure diagnosis: what now covers the weeks after a new diagnosis.

When you need urgent help

Some readings should not wait for a whole measuring period. The US National Heart, Lung, and Blood Institute says a reading above 180/120 mmHg needs medical attention, and to call 9-1-1 if a repeat reading is also high and you have a sudden severe headache, difficulty breathing, sudden severe pain in the chest, abdomen or back, numbness or weakness, a sudden change in vision, or problems talking. Then you do not hesitate and do not wait for the next reading. Call your local emergency number (112 in the EU, 999 in the UK, 911 in the US).

Without such symptoms, a single very high reading is not necessarily a crisis. Wait 5 minutes and check again, as the National Heart, Lung, and Blood Institute advises. If it is still high, contact your doctor straight away.

Keep your measurement week in Sam and bring the report

You go to the appointment with a record of your measurement week instead of a loose sheet to search for. The high blood pressure program is a diary with a doctor report, made for high blood pressure confirmed by a doctor.

• Instead of a paper log and writing slips: you enter each value with date, arm and pulse, or Sam takes over values your cuff has written to Apple Health.
• Instead of remembering: sleep and resting heart rate come from Apple Health, and you write only what you know, such as circumstances and how you felt.
• Instead of single values: the doctor report (PDF) brings together the period you choose to print or show.

Sam does not measure blood pressure, and the 24-hour monitor is not read by Sam.

Try Sam for free

Sam is a wellness companion, not a medical device. The app does not diagnose, treat, cure or prevent any condition or health state. Always consult qualified professionals for medical decisions.

Related reading

• Blood pressure log: print or app
• How often to measure blood pressure
• High blood pressure diagnosis: what now
• Living with high blood pressure: daily readings

Sources

Updated: October 2026

• NHS: Blood pressure test (page last reviewed 25 November 2025). Home measurement, two readings about one minute apart, morning and evening, and the 24-hour monitor.
• NHS: High blood pressure (page last reviewed 19 July 2024). Clinic and home thresholds, home monitor and 24-hour monitor to confirm the diagnosis.
• National Heart, Lung, and Blood Institute (NIH): High blood pressure diagnosis (updated 26 June 2025). Preparing for a reading.
• National Heart, Lung, and Blood Institute (NIH): High blood pressure symptoms (updated 25 April 2024). Above 180/120: wait 5 minutes, check again, call 9-1-1 with symptoms.
• Blood Pressure UK: Monitoring your blood pressure at home. White coat effect, validated automatic upper arm monitor, and NICE recommending home blood pressure monitoring.
• Blood Pressure UK: Medications for high blood pressure. Taking medicines as prescribed and reviewing with your doctor or nurse.