<story><title>Blood pressure should be measured lying down: study</title><url>https://newsroom.heart.org/news/high-blood-pressure-while-lying-down-linked-to-higher-risk-of-heart-health-complications</url></story><parent_chain><item><author>hwillis</author><text>&amp;gt; so nobody measures it as frequently as they do their pulse. Once we have the technology to accurately and passively measure blood pressure throughout the day&lt;p&gt;It&amp;#x27;s surprisingly tricky.  The way a BP cuff works (the auscultatory method[1]) is that the pressure is continuously decreased and you listen for the sound of a pulse.  When the cuff pressure is higher than your systolic (peak) pulse, bloodflow is blocked and you don&amp;#x27;t hear a pulse.  When the cuff pressure is lower than your diastolic, the cuff is no longer blocking bloodflow at all, and the pulse suddenly becomes much quieter because it&amp;#x27;s not restricted.  It&amp;#x27;s only between the two pressures that you hear it extra clearly.&lt;p&gt;So the problem with a sensor is that you can&amp;#x27;t just measure pressure against the skin.  At minimum, it really should actually impede a large artery.  You can squeeze the arm as tight as you like but if the brachial artery is not affected then your measurement will be very poor.&lt;p&gt;You can do fancy computer vision etc to look at special veins&amp;#x2F;arteries, and coupled with some demographic assumptions you can infer somewhat accurate measurements- but they really miss out on outliers, which is really a lot of the point of taking measurements.  This also generally will require an upper arm strap or something, and be fairly tight.  Not great to wear always&lt;p&gt;At some point, I think we will probably see implantable blood pressure monitoring.  We do something similar with implantable glucose monitors- which need regular replacement, unfortunately.  BP probably wouldn&amp;#x27;t.  Problem is that direct pressure measurement is usually done by tapping off an artery- something that will never be routine.  You&amp;#x27;d want to do some combination of acoustic and pressure measurement, and it&amp;#x27;d need to be calibrated from a base station regularly.&lt;p&gt;[1]: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Blood_pressure_measurement#&amp;#x2F;media&amp;#x2F;File:Blood_pressure_measurement_principle.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Blood_pressure_measurement#&amp;#x2F;me...&lt;/a&gt;</text></item><item><author>TechBro8615</author><text>I think the bigger issue with measuring blood pressure is that, aside from diagnosed diabetics, it&amp;#x27;s a measurement done infrequently and at mostly arbitrary times. Your blood pressure reading on the day of a doctor&amp;#x27;s appointment, right after you&amp;#x27;ve driven to the appointment, made your way through the intake pipeline, and finally sat down in the chair, is not representative of its reading during a typical day in your life. Other factors like recency of coffee or alcohol consumption, exercise and sleep, all combine to make blood pressure a fairly variable statistic with limited diagnostic power when it&amp;#x27;s only measured infrequently.&lt;p&gt;Regardless of whether you&amp;#x27;re lying down, standing up, or sitting in a chair, it would be beneficial to take more frequent blood pressure readings, throughout the day and during typical routines, than it would to only take them every time you visit the doctor. This seems like common sense, and you can even buy blood pressure sensors for $20 on Amazon, but how many people take their blood pressure on a regular basis? Once you&amp;#x27;re a diagnosed diabetic, then maybe you start measuring it every day - but wouldn&amp;#x27;t it be better to start such a habit &lt;i&gt;before&lt;/i&gt; you become diabetic? After all, if you&amp;#x27;re continuously measuring a variable then you can notice patterns and anomalies, and take steps to mitigate them - possibly avoiding becoming diabetic before it&amp;#x27;s too late.&lt;p&gt;It seems the limiting factor is sensor technology, which is obviously lacking compared to wearable sensors for tracking heart rate. Any health-conscious person with an Apple Watch or similar wearable device can easily track their pulse throughout the day. But no similarly accurate and seamless sensor exists for measuring blood pressure (as far as I know?), so nobody measures it as frequently as they do their pulse. Once we have the technology to accurately and passively measure blood pressure throughout the day, preventive medicine will become much easier, and people will have a better feeling for how their blood pressure responds to small changes in their environment and lifestyle.</text></item></parent_chain><comment><author>TechBro8615</author><text>I wonder if there are methods that could take advantage of natural movements throughout the day, where your body naturally emulates what the cuff forces it to do. For example, when you transition suddenly from sitting to standing, is it possible for a sensor to measure some proxy metric that, combined with an accelerometer, can be used to infer blood pressure? If there is some method like this, even if it has large margins of error, maybe cumulative measurements could converge on a fairly accurate reading?&lt;p&gt;(I&amp;#x27;m not a medical professional nor do I know much about sensing, or even really the basics of how blood pressure is measured or what it indicates.)</text></comment>
<story><title>Blood pressure should be measured lying down: study</title><url>https://newsroom.heart.org/news/high-blood-pressure-while-lying-down-linked-to-higher-risk-of-heart-health-complications</url></story><parent_chain><item><author>hwillis</author><text>&amp;gt; so nobody measures it as frequently as they do their pulse. Once we have the technology to accurately and passively measure blood pressure throughout the day&lt;p&gt;It&amp;#x27;s surprisingly tricky.  The way a BP cuff works (the auscultatory method[1]) is that the pressure is continuously decreased and you listen for the sound of a pulse.  When the cuff pressure is higher than your systolic (peak) pulse, bloodflow is blocked and you don&amp;#x27;t hear a pulse.  When the cuff pressure is lower than your diastolic, the cuff is no longer blocking bloodflow at all, and the pulse suddenly becomes much quieter because it&amp;#x27;s not restricted.  It&amp;#x27;s only between the two pressures that you hear it extra clearly.&lt;p&gt;So the problem with a sensor is that you can&amp;#x27;t just measure pressure against the skin.  At minimum, it really should actually impede a large artery.  You can squeeze the arm as tight as you like but if the brachial artery is not affected then your measurement will be very poor.&lt;p&gt;You can do fancy computer vision etc to look at special veins&amp;#x2F;arteries, and coupled with some demographic assumptions you can infer somewhat accurate measurements- but they really miss out on outliers, which is really a lot of the point of taking measurements.  This also generally will require an upper arm strap or something, and be fairly tight.  Not great to wear always&lt;p&gt;At some point, I think we will probably see implantable blood pressure monitoring.  We do something similar with implantable glucose monitors- which need regular replacement, unfortunately.  BP probably wouldn&amp;#x27;t.  Problem is that direct pressure measurement is usually done by tapping off an artery- something that will never be routine.  You&amp;#x27;d want to do some combination of acoustic and pressure measurement, and it&amp;#x27;d need to be calibrated from a base station regularly.&lt;p&gt;[1]: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Blood_pressure_measurement#&amp;#x2F;media&amp;#x2F;File:Blood_pressure_measurement_principle.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Blood_pressure_measurement#&amp;#x2F;me...&lt;/a&gt;</text></item><item><author>TechBro8615</author><text>I think the bigger issue with measuring blood pressure is that, aside from diagnosed diabetics, it&amp;#x27;s a measurement done infrequently and at mostly arbitrary times. Your blood pressure reading on the day of a doctor&amp;#x27;s appointment, right after you&amp;#x27;ve driven to the appointment, made your way through the intake pipeline, and finally sat down in the chair, is not representative of its reading during a typical day in your life. Other factors like recency of coffee or alcohol consumption, exercise and sleep, all combine to make blood pressure a fairly variable statistic with limited diagnostic power when it&amp;#x27;s only measured infrequently.&lt;p&gt;Regardless of whether you&amp;#x27;re lying down, standing up, or sitting in a chair, it would be beneficial to take more frequent blood pressure readings, throughout the day and during typical routines, than it would to only take them every time you visit the doctor. This seems like common sense, and you can even buy blood pressure sensors for $20 on Amazon, but how many people take their blood pressure on a regular basis? Once you&amp;#x27;re a diagnosed diabetic, then maybe you start measuring it every day - but wouldn&amp;#x27;t it be better to start such a habit &lt;i&gt;before&lt;/i&gt; you become diabetic? After all, if you&amp;#x27;re continuously measuring a variable then you can notice patterns and anomalies, and take steps to mitigate them - possibly avoiding becoming diabetic before it&amp;#x27;s too late.&lt;p&gt;It seems the limiting factor is sensor technology, which is obviously lacking compared to wearable sensors for tracking heart rate. Any health-conscious person with an Apple Watch or similar wearable device can easily track their pulse throughout the day. But no similarly accurate and seamless sensor exists for measuring blood pressure (as far as I know?), so nobody measures it as frequently as they do their pulse. Once we have the technology to accurately and passively measure blood pressure throughout the day, preventive medicine will become much easier, and people will have a better feeling for how their blood pressure responds to small changes in their environment and lifestyle.</text></item></parent_chain><comment><author>jkingsman</author><text>Worth mentioning that BP is about &lt;i&gt;arterial&lt;/i&gt;, not venous pressure. Venous pressure is an order of magnitude lower than arterial pressure; usually 0-10mmHg.</text></comment>