From the Guidelines
To calculate your average blood pressure from 7 days of readings, first take all measurements at consistent times each day—morning and evening—on both arms, as recommended by the 2024 ESC guidelines for the management of elevated blood pressure and hypertension 1. Record each reading with its systolic (top) and diastolic (bottom) numbers. After collecting all 28 readings (7 days × 2 times per day × 2 arms), add up all systolic values and divide by 28 to get your average systolic pressure. Do the same with all diastolic values to get your average diastolic pressure. These two numbers together represent your average blood pressure. For the most accurate results, sit quietly for 5 minutes before each measurement, use the same validated device each time, position your arm at heart level, and avoid caffeine, exercise, and smoking for 30 minutes beforehand, as suggested by the 2019 AHA/ACC clinical performance and quality measures for adults with high blood pressure 1. If you notice a consistent difference of more than 10 mmHg between arms, mention this to your healthcare provider as it could indicate underlying vascular issues. This averaging method provides a more reliable picture of your blood pressure than single readings because blood pressure naturally fluctuates throughout the day due to factors like stress, activity, and medication timing. Some key points to consider when taking these measurements include:
- Using a validated BP device 1
- Measuring BP in a quiet room after 5 min of rest with arm and back supported 1
- Obtaining two readings on each occasion, 1–2 min apart 1
- Recording and averaging all readings and presenting results to a clinician 1
- Obtaining readings twice a day (morning and evening) for at least 3 and ideally 7 days 1
From the Research
Calculating Average Blood Pressure
To calculate the average blood pressure using 7 days of readings from both arms, morning and evening, follow these steps:
- Take blood pressure readings from both arms, morning and evening, for 7 consecutive days.
- Record the systolic and diastolic blood pressure values for each reading.
- Calculate the average systolic and diastolic blood pressure for each day by adding the morning and evening values and dividing by 2.
- Calculate the overall average systolic and diastolic blood pressure for the 7-day period by adding the daily average values and dividing by 7.
Considerations for Blood Pressure Readings
When taking blood pressure readings, consider the following:
- Use a reliable blood pressure monitor to ensure accurate readings 2.
- Take readings at the same time each day, ideally in the morning and evening, to account for any fluctuations in blood pressure throughout the day.
- Sit comfortably with your back supported and feet flat on the floor, with your arm at heart level, to ensure accurate readings.
Interpreting Blood Pressure Readings
When interpreting blood pressure readings, consider the following:
- Normal blood pressure is typically defined as a systolic pressure less than 120 mmHg and a diastolic pressure less than 80 mmHg 3.
- Elevated blood pressure may require lifestyle changes or medication to manage, as outlined in studies on hypertension treatment 4, 5, 6.
- Consult with a healthcare professional to determine the best course of action for managing your blood pressure.