A new study in JAMA Cardiology shows people with high blood pressure measured lying down (supine) was linked to a higher risk of heart disease, stroke and death regardless of the seating blood pressure reading. They also found in 16 % of the people tested had ONLY high blood pressure when measured lying flat (called supine hypertension) that would have been missed by only taking blood pressure readings in the seated position.
How is blood pressure usually measured?
Blood pressure is usually taken in the arm in the seated position with the arm supported on a desk, the ARMS trial says this gives us the most reliable sitting measurement. However, based on the New study taking blood pressure both sitting AND lying flat was valuable in not missing people with high blood pressure but also identifying those people who may benefit from better blood pressure control sooner.
Taking blood pressure lying down is very similar to seating per the American Heart Association and is easy to do. Blood pressure can be measured at home in bed, sofa or recliner or when lying down on the exam table in the doctor’s office. It’s best to position the arm of blood pressure cuff propped up on a pillow, so your arm is at the same height as the top of your heart.
Like all blood pressure readings, it should be taken 2 or 3 times and averaged together. You must be relaxed for 5 minutes, no coffee, caffeinated drinks or smoking for at least 30 minutes, bladder should be empty (as full bladder may raise blood pressure) and always use the correct sized cuff for your arm as a too small of a cuff can make your blood pressure seem higher than it really is.
Why should your doctor take blood pressure lying flat or supine?
Studies say that high nighttime or nocturnal high blood pressure is a bad thing while we sleep as blood pressure (BP) is lower during this time of relaxation and rest called “nocturnal BP dipping,” and if high puts us at even higher risk for a stroke, and heart attack. Researchers feel that measuring BP lying down can detect those people at higher risk and treat them sooner.
The study out of JAMA Cardiology followed over 11,000 adults without heart disease or prior stroke over 25 years and found that 3/4 had elevated blood pressure (greater than 130/80) in both sitting and lying positions and 16 % in the supine or lying position ONLY. Those with high blood pressure reported in both positions or ONLY in the supine position suffered more strokes, heart attacks, and died sooner.
What is the blood pressure goal?
The goal for seating or lying blood pressure as set by the American College of Cardiology is less than 120/80 with high blood defined as a BP of 130-139/80-89 or greater. BP of 140/80 was considered normal until the SPRINT trial came along showing that people with lower blood pressures of 120/80 or less had fewer strokes, heart attacks, and death. Your blood pressure taken lying or sitting should fall within these targets.
And next time you go to the doctor’s office consider having your BP checked BOTH sitting and lying to be sure your blood pressure is normal or well controlled on medications in all positions. That said, it’s still not common practice to take BP lying down on a routine basis, and more research needs to be done however we do know that high nighttime blood pressure while lying down is linked to more strokes, and heart attacks and testing blood pressure lying down on a regular basis may end up being the standard of care in the future.
So, there’s no harm in asking or checking your blood pressure lying down at home or in the doctor’s office, as high blood pressure is often called the “silent killer,” so important to detect and treat early as 16 % of people in this large trial would have been missed if blood pressure was not taken lying down or in the supine position.
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