Scientists at Yale University have found that blood pressure readings taken during doctor’s visits can vary a lot from one appointment to the next. This big difference between measurements makes it hard for doctors to tell if treatments for high blood pressure are actually working.
The study highlights why home blood pressure monitoring is so important. Keeping an eye on blood pressure outside of the doctor’s office could give a clearer and more reliable picture of a person’s true blood pressure over time.
Nearly half of adults in the United States have high blood pressure, also called hypertension. Sadly, only about 1 in 4 people with high blood pressure have it under control. High blood pressure is usually defined as having a top number (systolic pressure) of 130 or higher, or a bottom number (diastolic pressure) of 80 or higher.
If left untreated, high blood pressure can lead to many serious health problems. These include heart attacks, strokes, heart failure, kidney disease, vision problems, and even memory loss or dementia later in life.
In this large study, the Yale research team looked at more than 7.7 million blood pressure readings from 537,218 adults, with an average age of 53, who were treated in the Yale New Haven Health System.
They found that blood pressure readings between two doctor visits varied by an average of about 12 mmHg — a very large difference when you are trying to track treatment progress.
Among people whose blood pressure was in the normal range, the systolic reading (the top number) still changed by an average of 6.3 mmHg between visits. For people with very high blood pressure — systolic readings above 180 mmHg — the difference between visits was even bigger, about 32.3 mmHg on average.
The study also showed that even if someone is given medicine meant to lower their systolic pressure by 10 mmHg, it would not always show clearly at their next visit.
In fact, 37% of the time, the next reading would show a drop of only 5 mmHg or less. And 25% of the time, it would show no drop at all. To be 80% sure that the treatment was working, it would take about four follow-up visits.
Because of this, the researchers suggest that both patients and doctors should not rely only on occasional office readings. Home monitoring can provide more data points and help doctors see real patterns over time.
To get the most accurate blood pressure reading, they recommend the following tips: avoid exercising, smoking, or drinking coffee within 30 minutes before measuring. Make sure to empty your bladder and sit quietly for at least five minutes before the test.
Rest your arm on a table at heart level, and use a cuff placed directly against bare skin, just above the bend of the elbow. Sit up straight in a chair with your feet flat on the floor. It’s best to take two readings one minute apart — once in the morning before breakfast or medications, and again in the evening before dinner.
If you’re interested in ways to improve blood pressure naturally, recent studies suggest that probiotics might help lower blood pressure, blood sugar, and cholesterol. Also, certain plant-based foods and cutting back on added sugars can make a big difference.
This important study was led by Yuan Lu and published in Circulation: Cardiovascular Quality and Outcomes. It reminds us that checking blood pressure properly — both at home and in the office — is key to managing this silent but dangerous condition.
If you care about blood pressure, please read studies about unhealthy habits that could increase high blood pressure risk, and people with severe high blood pressure should reduce coffee intake.
For more information about blood pressure, please see recent studies that early time-restricted eating could help improve blood pressure, and results showing plant-based foods could benefit people with high blood pressure.
Copyright © 2025 Knowridge Science Report. All rights reserved.
