How should I correctly measure my blood pressure at home?

How to Correctly Measure Blood Pressure at Home

Use a validated automated upper-arm device and measure twice daily (morning before medications and evening) for 7 consecutive days, taking 2 readings per session 1–2 minutes apart, then average all readings except the first day to guide treatment decisions. 1

Equipment Requirements

• Purchase only a validated automated oscillometric upper-arm device that meets international standards (AAMI, BHS, or International Protocol). 1, 2
• Avoid wrist devices—they produce unreliable readings in real-world home use due to frequent positioning errors. 3
• Select a device with memory storage capability to prevent selective reporting of readings. 1, 2
• Ensure the cuff bladder encircles 75–100% of your arm circumference; an incorrectly sized cuff produces inaccurate measurements. 1
• Bring your device to clinic appointments at least annually for accuracy verification against office measurements. 2

Pre-Measurement Preparation

Before every measurement session, you must:

• Empty your bladder. 1
• Avoid caffeine, tobacco, and exercise for 30 minutes before measuring. 1
• Rest quietly for 5 minutes in a seated position before taking the first reading. 1

Correct Body Positioning

Proper positioning is critical for accuracy:

• Sit in a chair with your back straight and fully supported (use a dining chair, not a sofa). 1
• Keep both feet flat on the floor with legs uncrossed. 1
• Support your arm on a flat surface at heart level (such as a table). 1
• Position the cuff directly above the bend of your elbow (antecubital fossa). 2
• Remain silent and still during the entire measurement. 1

Measurement Schedule and Timing

Follow this specific protocol:

Morning Measurements

• Take readings within 1 hour after waking, after urination, before breakfast, and before taking any blood pressure medications—but not immediately upon awakening. 1, 2, 4
• Perform 2 readings separated by 1–2 minutes. 1

Evening Measurements

• Take readings before dinner or at a consistent pre-specified time, or just before bedtime. 1, 2
• Again perform 2 readings separated by 1–2 minutes. 1

Duration of Monitoring Period

• Measure for 7 consecutive days. 1, 2
• Discard all readings from the first day because they show greater variability. 1, 2
• This yields a minimum of 12 morning and 12 evening readings (24 total from days 2–7). 1, 2

Recording and Calculating Results

• Record every single reading without exception—never selectively report only "good" readings, as this invalidates the data. 2
• Calculate the average of all readings from days 2–7 (excluding day 1). 1, 2
• This average is the reference value your clinician will use for treatment decisions. 1, 2

Understanding Your Numbers

Diagnostic Thresholds

• Home blood pressure ≥135/85 mmHg indicates hypertension (equivalent to office BP ≥140/90 mmHg). 1, 2
• Home BP of 120–134/70–84 mmHg indicates elevated blood pressure. 1

Treatment Targets

• Standard patients: target home BP <135/85 mmHg. 2
• High-risk patients (diabetes, coronary artery disease, chronic kidney disease): target home BP <130/80 mmHg. 2, 5

Long-Term Monitoring Schedule

After initial diagnosis:

• Stable, controlled patients: repeat a 7-day monitoring period every 3 months (quarterly). 2
• During medication changes: repeat monitoring 2–4 weeks after starting or adjusting medications to assess response. 1, 2
• Poor medication adherence: monitor more frequently as directed by your clinician. 2

Arm Selection

• Use your non-dominant arm for consistency. 4
• If your clinician has detected a significant difference between arms (>10 mmHg), always use the arm with the higher readings. 1, 4
• Avoid measuring in an arm with an arteriovenous fistula or after axillary lymph node surgery. 1

Common Pitfalls to Avoid

• Never base decisions on a single day of measurements—they lack reliability. 2
• Do not take extra measurements when feeling stressed or symptomatic; stick to the scheduled protocol. 2
• Avoid automated devices in pharmacies or shopping malls—they are often inaccurate. 2, 5
• Do not use finger-cuff devices—only validated upper-arm monitors are acceptable. 2
• Do not measure immediately after waking—allow time for morning activities first. 4

When Home Monitoring Is Unreliable

Home blood pressure monitoring using oscillometric devices is unreliable in patients with atrial fibrillation or frequent irregular heartbeats. 2 If you have these conditions, discuss alternative monitoring methods with your clinician.

Clinical Value

Home blood pressure monitoring predicts cardiovascular risk more accurately than office measurements because it provides many more readings, eliminates the "white-coat effect" (artificially elevated readings in medical settings), and shows superior reproducibility. 2, 5 Morning readings are particularly important as they predict future cardiovascular events more strongly than evening readings. 2