The science behind on-the-wrist blood pressure tracking(empirical.health)
empirical.health
The science behind on-the-wrist blood pressure tracking
https://www.empirical.health/blog/apple-watch-blood-pressure/
105 comments
> However, one thing to be aware of is that you are not used to seeing your BP readings from the entire day.
Same thing with those continuous glucose monitors that almost anyone can get and put on their arm now. The vast majority of the data and recommendations we have are for diabetics using regular single use measurements or a proper glucose tolerance test so shortly after the user eats a bowl of rice while wearing it, it sends them into a hypochondriac spiral when they see a peak of 200. Their doctor generally has to talk them down. There's just not that much data on what the average healthy person's response to blood sugar is, especially when it's continuously monitored.
Same thing with those continuous glucose monitors that almost anyone can get and put on their arm now. The vast majority of the data and recommendations we have are for diabetics using regular single use measurements or a proper glucose tolerance test so shortly after the user eats a bowl of rice while wearing it, it sends them into a hypochondriac spiral when they see a peak of 200. Their doctor generally has to talk them down. There's just not that much data on what the average healthy person's response to blood sugar is, especially when it's continuously monitored.
One of the things I wish had come out of the Quantified Self movement (which is now so mainstream, it wasn't even mentioned in this article), was a consensus awareness of how to mentally handle fluctuations when recording more data.
We already knew that things like weight fluctuated in normal people (periods, hydration, meals, etc), but many of us are still defaulting to the inaccurate model of slowly-changing measurements recorded 1x/2x a year at the doctor's office.
I'm sure people will get used to it, and many of the weight apps already wisely show averages to discourage fixating on individual measurements, but it feels like a missed opportunity.
We already knew that things like weight fluctuated in normal people (periods, hydration, meals, etc), but many of us are still defaulting to the inaccurate model of slowly-changing measurements recorded 1x/2x a year at the doctor's office.
I'm sure people will get used to it, and many of the weight apps already wisely show averages to discourage fixating on individual measurements, but it feels like a missed opportunity.
From my point of view, that's the whole point of wearing a continuous biometric monitor so that you can see the normal variation. These one off medical tests that people use to make major life and health decisions seems kinda crazy to me.
> There's just not that much data on what the average healthy person's response to blood sugar is, especially when it's continuously monitored.
Chicken and egg situation, no?
People are advised not to use those devices because there isn't much data about them for otherwise healthy people. But if they don't use those devices, there won't be much data.
Chicken and egg situation, no?
People are advised not to use those devices because there isn't much data about them for otherwise healthy people. But if they don't use those devices, there won't be much data.
The data has to be collected under clinical conditions to control for confounding variables. People are notoriously bad at accurately recording their precise food intake which is probably the most important variable here. They need to do smaller controlled studies with provided diets. Large scale population studies with sensor data in the wild is going to be a trickier proposition that requires linking the sensors to the rest of the patients medical records which is a privacy mine field.
> However, one thing to be aware of is that you are not used to seeing your BP readings from the entire day. Did you jump in a cold plunge 10 minutes before it ran? Get ready to see a really high reading dot in the 'danger zone'. Went for a jog and are catching your breath on a park bench? High dot.
This is a great point. Blood pressure readings are only useful in the context of stationary measurements under known conditions. Blood pressure is inherently volatile and depends on activity and recent movements, or to extreme events like cold exposure.
There are even finger-cuff blood pressure monitors designed for continuous, constant blood pressure measurement in the context of a lab or hospital setting. Their measurements would be useless in the context of someone moving around all day, but it can be useful in the context of someone under anesthesia or undergoing a controlled lab test.
This is a great point. Blood pressure readings are only useful in the context of stationary measurements under known conditions. Blood pressure is inherently volatile and depends on activity and recent movements, or to extreme events like cold exposure.
There are even finger-cuff blood pressure monitors designed for continuous, constant blood pressure measurement in the context of a lab or hospital setting. Their measurements would be useless in the context of someone moving around all day, but it can be useful in the context of someone under anesthesia or undergoing a controlled lab test.
> Blood pressure readings are only useful in the context of stationary measurements under known conditions.
This isn't fully true. For clinical reference to known "good" number ranges, then yes, you want to make the comparison as accurate as possible.
Butm there's a lot of potential unlocked with more data.
For example, we could discover that daily BP averages are more predictive than isolated doctor's office measurements. Imagine two people with equal BP measures at the doc's, but one has a more stressful job with higher average BP. We might reasonably expect them to have worse cardiac outcomes. Or consider the person who's anxious about docs and consistently shows higher numbers in the office than outside; we'd expect the reverse!
Another factor might be examining the variance. This already has precedents, since we know there are things that heart rate variability (HRV) correlate with more strongly than heart rate itself.
This isn't fully true. For clinical reference to known "good" number ranges, then yes, you want to make the comparison as accurate as possible.
Butm there's a lot of potential unlocked with more data.
For example, we could discover that daily BP averages are more predictive than isolated doctor's office measurements. Imagine two people with equal BP measures at the doc's, but one has a more stressful job with higher average BP. We might reasonably expect them to have worse cardiac outcomes. Or consider the person who's anxious about docs and consistently shows higher numbers in the office than outside; we'd expect the reverse!
Another factor might be examining the variance. This already has precedents, since we know there are things that heart rate variability (HRV) correlate with more strongly than heart rate itself.
Anecdotally I find my blood pressure (measured with a regular upper-arm cuff while sitting) to often be lowest soon after completing a workout, like a hard 5K run outside. I'm not sure why, maybe the vasodilation effect from increased nitric oxide production?
IANAM, but if cardiac output is constant (say) and HR ↑ then you would expect BP ↓. I think that indicates good health too, that you don't need increased output, HR is just increasing to move oxygen around faster.
Yes, it indicates good health. Flexible arteries are healthy arteries. If you have high BP at night when sleeping that is very unhealthy. I urge anyone who has high blood pressure readings to get a 24 hour BP monitor to rule out labile hypertension.
IIRC there's also a Samsung Galaxy Watch that does blood pressure monitoring, with similar requirements. Have to work a bit to get the app installed in the US, but then it takes periodic measurements, is fairly accurate, and requires calibration once a month.
I was really hoping Apple was going to bring BP to the watch this year, but my guess is the regular external calibration requirement is too much for their plug-and-play philosophy.
I was really hoping Apple was going to bring BP to the watch this year, but my guess is the regular external calibration requirement is too much for their plug-and-play philosophy.
+1. I also use Samsung Galaxy Watch (Active2) and find it to work well for me. I'm surprised more people don't know about it. I know couple of people that suffer from high BP. They showed little interest when I told them about the watch.
Regular external calibration helped me build confidence. I was suspicions if the watch worked, and how well it worked. Calibration is every month - it expires. I take 3 measurements in parallel watch-cuff, and tell the watch App what the cuff measured. I didn't mind it initially. I now find it annoying tbh. I see why Apple would like to get rid of it. Post calibration, I measure 3 times in parallel both watch and cuff to check if they match. If the difference is within 5% - then fine. In 3 years it's happened twice where they differed more and I had to recalibrate. From recollection - both times with a reason, a TV was turned on in living room.
I have the impression that BP measurements differ though the day (lower in the morning, higher in the evening), depending on activity or at rest of course, I think there maybe some seasonality too (winter v.s. summer). Measuring BP when going to the doctor once a year strikes me as a wholly inadequate. If the BP is absurdly high out of normal range - then yeah, we learn something is wrong with the patient. But in any other case - don't see what can be deduced from 1 random measurement.
To check if the calibration is important, I had my wife use the watch, that is calibrated on me. She got absurd readings. So yes - the calibration is important and is tied to the person that did the calibration. (edited to add this)
Regular external calibration helped me build confidence. I was suspicions if the watch worked, and how well it worked. Calibration is every month - it expires. I take 3 measurements in parallel watch-cuff, and tell the watch App what the cuff measured. I didn't mind it initially. I now find it annoying tbh. I see why Apple would like to get rid of it. Post calibration, I measure 3 times in parallel both watch and cuff to check if they match. If the difference is within 5% - then fine. In 3 years it's happened twice where they differed more and I had to recalibrate. From recollection - both times with a reason, a TV was turned on in living room.
I have the impression that BP measurements differ though the day (lower in the morning, higher in the evening), depending on activity or at rest of course, I think there maybe some seasonality too (winter v.s. summer). Measuring BP when going to the doctor once a year strikes me as a wholly inadequate. If the BP is absurdly high out of normal range - then yeah, we learn something is wrong with the patient. But in any other case - don't see what can be deduced from 1 random measurement.
To check if the calibration is important, I had my wife use the watch, that is calibrated on me. She got absurd readings. So yes - the calibration is important and is tied to the person that did the calibration. (edited to add this)
Most people don’t know about this feature on the galaxy watch because it’s only approved in certain countries, though you can hack the SHM to enable it.
Are the sensors already capable of it? Maybe someone could make a third party app for the watch
Was unaware of the Aktiia. Thank you for posting. I saw firsthand how CGM changed my behavior and would love the same for ketones and blood pressure.
I am particularly excited about the UT Austin research[1] that used conductive temporary tattoos to get actual real time data and not just polling at intervals. However it’s not yet at the stage of commercialization and the design is more the width of a cuff than a watch.
[1] https://scitechdaily.com/electronic-tattoo-offers-highly-acc...
I am particularly excited about the UT Austin research[1] that used conductive temporary tattoos to get actual real time data and not just polling at intervals. However it’s not yet at the stage of commercialization and the design is more the width of a cuff than a watch.
[1] https://scitechdaily.com/electronic-tattoo-offers-highly-acc...
I'll bet blood pressure readings throughout the day will be analogous to the data we get from CGMs (continuous glucose monitors). You get lots of spikes during the day.
Given enough data pairing continuous blood pressure with major events like heart attacks and strokes, we may even develop more accurate models to predict which types of spikes create the most cardiovascular risk.
Given enough data pairing continuous blood pressure with major events like heart attacks and strokes, we may even develop more accurate models to predict which types of spikes create the most cardiovascular risk.
Totally agree, although perhaps the real gift of this technology will be from the fact that people can be more aware of the underlying conditions (high BP) and tighter feedback loops on how to reduce it / manage it vs. just helping notify about an acute emergency situation.
As I typed the above sentence out, I thought "why not both?". Use the technology to reduce your risk, but in the event that the bad event still happens the notification could save your life.
As I typed the above sentence out, I thought "why not both?". Use the technology to reduce your risk, but in the event that the bad event still happens the notification could save your life.
I found the exact reverse with the jog. One day I went into the mountains with a cuff on my wrist and took a bunch of measurements. I wasn't jogging but I had something like 25 pounds on my back and was definitely pushing myself.
There was a huge effect from perceived temperature--while I didn't do the cold plunge I got some quite high readings when I was on the chilly side. Yet I could get low-normal readings with my heart rate above 130 which is the highest I could go at that elevation. Obviously I couldn't actually take a reading while moving but I could have it on my wrist, stop and immediately press the button. The pattern I observed was activity raises temperature which lowers blood pressure.
There was a huge effect from perceived temperature--while I didn't do the cold plunge I got some quite high readings when I was on the chilly side. Yet I could get low-normal readings with my heart rate above 130 which is the highest I could go at that elevation. Obviously I couldn't actually take a reading while moving but I could have it on my wrist, stop and immediately press the button. The pattern I observed was activity raises temperature which lowers blood pressure.
Thanks for sharing. For me, I can see that DURING exercise, my blood pressure is quite raised but then drops down lower than usual in the hours that follow. However, I think that's more a function of resting HR - which remains elevated.
My particular BP scenario is good diastolic, high systolic but low rest heart rate (low 50s). My pet theory is that my heart does fewer but stronger pumps, which increases the BP. After exercising, when heart rate remains elevated, the BP is lower since the heart is doing more frequent but less powerful beats.
Just a pet theory, I haven't even discussed it with a medical professional.
My particular BP scenario is good diastolic, high systolic but low rest heart rate (low 50s). My pet theory is that my heart does fewer but stronger pumps, which increases the BP. After exercising, when heart rate remains elevated, the BP is lower since the heart is doing more frequent but less powerful beats.
Just a pet theory, I haven't even discussed it with a medical professional.
The *only* pattern I could find was it was inversely related to *perceived* temperature. The doc said that relationship was to be expected. My blood pressure would not be elevated even during the recovery period.
This is super exciting, thanks for posting! I developed high blood pressure after Covid and have done a few 24h studies to better understand it. The traditional machines are super bulky, essentially like carrying a regular BP monitor around with a pouch that's strapped to you, maybe just a bit smaller. All in all it's far from convenient and can kick in at inopportune times. Having around the clock insights would hopefully give me a better understanding of the condition. For context, I've jumped through all sorts of specialty doctor hoops and there is no known underlying cause outside of the fact that it just showed up after Covid.
Do you or anyone you know happen to have firsthand experience with the device?
Do you or anyone you know happen to have firsthand experience with the device?
Hey I have firsthand experience with it as indicated in the post. Probably a few months worth of wear at this point.
BP remains a great mystery to me, even with the device. My cardio fitness is pretty good despite carrying a few extra pounds (I'm in the low 50s for resting heart rate), and while overnight I dip down in the 120's, I can see it shoot up based on various things like cold plunge, caffeine, exercise (during), etc. I can also see it drop temporarily (hot tub, meditation, the hours FOLLOWING intense exercise, etc).
I had many pet theories through the years - that I had white coat syndrome, that I disliked the feeling of the cuff, etc etc. But the device showed me that, no, something really is going on independent of these pseudo-causes.
BTW water retention seems to play a big role. When I did keto, which causes a big drop in water retention, my BP also went down. Strange. Supplements have an impact too.
All this to say - get the device and see for yourself, but you might find yourself in the same place I am - which is that you have much better understanding of what's going on in terms of symptoms but are still on the search for "the underlying cause" if there even is such a thing.
BP remains a great mystery to me, even with the device. My cardio fitness is pretty good despite carrying a few extra pounds (I'm in the low 50s for resting heart rate), and while overnight I dip down in the 120's, I can see it shoot up based on various things like cold plunge, caffeine, exercise (during), etc. I can also see it drop temporarily (hot tub, meditation, the hours FOLLOWING intense exercise, etc).
I had many pet theories through the years - that I had white coat syndrome, that I disliked the feeling of the cuff, etc etc. But the device showed me that, no, something really is going on independent of these pseudo-causes.
BTW water retention seems to play a big role. When I did keto, which causes a big drop in water retention, my BP also went down. Strange. Supplements have an impact too.
All this to say - get the device and see for yourself, but you might find yourself in the same place I am - which is that you have much better understanding of what's going on in terms of symptoms but are still on the search for "the underlying cause" if there even is such a thing.
Thanks for sharing your experience, I appreciate it. What I've seen from the 24h studies I've is very similar to what you describe, BP is highly variable throughout the day and nearly everything you do (or don't do) has an influence on it. One saving grace, if you can call it that, is that BP responds extremely well to medication. I take a small pill every morning and my doc says so long I keep it up, I've nullified all related health risk since my BP is now in a good range. So something to consider if, like me, you never find an underlying reason.
I've found similar. I don't know if it was post-Covid, but I have completely asymptomatic high blood pressure. It's really scary to go to the doctor for an extremely routine health check expecting to be back at work in an hour, and then suddenly be told that your blood pressure is so high that you need to go to hospital immediately.
There's no obvious cause, I'm fit and healthy in all other ways, I've had multiple blood tests and ECGs, my cholesterol is normal, everything is normal, just the blood pressure. I also didn't know about this machine but I might get one. I have developed anxiety around having it taken (because of the experience of getting sent to hospital!) so it goes up when I take it, like extreme white-coat syndrome.
I'm definitely getting one of these gadgets so I can see what it really is, without the stress and pain (those things hurt!) of inflating cuffs.
There's no obvious cause, I'm fit and healthy in all other ways, I've had multiple blood tests and ECGs, my cholesterol is normal, everything is normal, just the blood pressure. I also didn't know about this machine but I might get one. I have developed anxiety around having it taken (because of the experience of getting sent to hospital!) so it goes up when I take it, like extreme white-coat syndrome.
I'm definitely getting one of these gadgets so I can see what it really is, without the stress and pain (those things hurt!) of inflating cuffs.
You can request a 24 hour monitor from your doctor.
Just curious if you BP was low/normal at night?
Not really, it was usually hovering right around the border of what's considered high blood pressure. As you might guess, the daytime numbers were off the charts compared to that. Luckily my body responds very well to the medication and a small dose is all I need to stay in a good range the whole day.
I have labile hypertension so my BP readings are whack. It is usually up at 160/100 at the doctors office but at home it is normal. Docs did not believe me and were trying to force me onto meds till they put a 24 hour monitor on me. BP spikes and drops during the day and drops to 100/60 at night.
Labile hypertension is the most difficult to treat. So far my heart is perfect for a late 50's dude. Just had an colorflow echocardiogram, no sign of hypertension in the heart. Probably because I eat so much fish.
If I drink coffee my BP is up all day though. I am just very sensitive.
https://en.wikipedia.org/wiki/Labile_hypertension
Labile hypertension is the most difficult to treat. So far my heart is perfect for a late 50's dude. Just had an colorflow echocardiogram, no sign of hypertension in the heart. Probably because I eat so much fish.
If I drink coffee my BP is up all day though. I am just very sensitive.
https://en.wikipedia.org/wiki/Labile_hypertension
Funny I had a similar experience, late twenties, felt completely healthy, but was constantly having chest pains. I was a bit over weight at the time but I walked everywhere and was really active, doctors office my BP was always ~ 140/80, he prescribed me meds but I wasn't satisfied with that. I went and got a full heart study done and a 24hr blood pressure monitoring done, my heart and BP are totally fine apparently.
I really freak out about getting my blood pressure taken in a clinical setting, it's really unusual.
I had some treatment for a kidney stone recently, and after the procedure they were checking me with some pretty accurate machines, like 10 times in 24 hours (apparently), 128/80, for some reason in that specific setting I didn't freak out.
White coat HT is a weird thing.
I really freak out about getting my blood pressure taken in a clinical setting, it's really unusual.
I had some treatment for a kidney stone recently, and after the procedure they were checking me with some pretty accurate machines, like 10 times in 24 hours (apparently), 128/80, for some reason in that specific setting I didn't freak out.
White coat HT is a weird thing.
I have frequent chest pains as well since my early 20s! They tell me it is costochondritis but my inflammatory markers are always exceptional. I know what it is now and it is totally neurological, both issues.
Wonder if you have noticed if you were neurologically sensitive to any types of foods?
Wonder if you have noticed if you were neurologically sensitive to any types of foods?
Eventually they subsided, I don't even remember when, and I've never really had them since...unless I have reflux, which does happen for me occasionally.
I'm learning I just can't really do coffee / caffeine though, I don't think it's ever really been good for me, it causes reflux and anxiety for me, but I just loved coffee to much. I gave up recently however!
You might have heart burn occasionally too ?
I'm learning I just can't really do coffee / caffeine though, I don't think it's ever really been good for me, it causes reflux and anxiety for me, but I just loved coffee to much. I gave up recently however!
You might have heart burn occasionally too ?
I cut out caffeine & my chest pain completely went away & never came back.
I am wondering if continuous blood pressure monitoring would have some knock-on effects as a measurable, correlatable negative health effect of stress.
It would mean that you can literally show that working conditions are shortening your life.
Your company's health insurance could look at BP during commuting hours and in the office vs. at home and raise rates on companies based on their policies.
It would mean that you can literally show that working conditions are shortening your life.
Your company's health insurance could look at BP during commuting hours and in the office vs. at home and raise rates on companies based on their policies.
Unfortunately they get very mixed reviews on Trustpilot, both for the product and for after-sales support:
https://www.trustpilot.com/review/aktiia.com (2.9/5)
https://www.trustpilot.com/review/aktiia.com (2.9/5)
Hmm... I remember reading that cuff blood pressure measurements require your arm to be supported. (and also explains why a lot of blood pressure measurements are inaccurate)
I wonder if you're calibrating on a supported arm, then letting your arm swing free later with the wrist device.
I wonder if you're calibrating on a supported arm, then letting your arm swing free later with the wrist device.
What extra useful information can you get from continuous BP measurement compared to once or twice daily measurement?
One real answer is "we don't know because this capability hasn't existed before" I mean, you can wear something like a traditional cuff that puffs itself up every five minutes or whatever, but that doesn't really fit into a patient/subjects life. Good like trying to recruit people for a long term longitudinal study.
But having worked in medical sensors, and spending time with researchers as customers, there was a real sense that they could learn a lot from BP readings that were accurate and continuous.
But having worked in medical sensors, and spending time with researchers as customers, there was a real sense that they could learn a lot from BP readings that were accurate and continuous.
How specific events throughout the day affect your BP, like things you ate, caffeine, a walk in the cold/heat, exercise, or a conversation. I'd say it's all useful info for perspective on how to manage stress and circulatory health.
I can see how the information can be useful from a big-data perspective (finding correlations between the data of thousands of people), but for individuals I'm not convinced yet. For example, how do you know if a spike in BP is normal, or if it's only happening in your specific case and it needs attention?
I think the best answer to that is ask your doctor if you see something that concerns you. Though, even without an expert opinion or big data as a reference, establishing what is a baseline for yourself and then noting when there is significant deviation can have value. It could be an early warning sign or just encouragement to get help if your BP is one day very high or low. Some googling can probably give you an idea of what are normal ranges based on activity, too.
> Aktiia
Looks interesting, but it too _requires_ a cloud account to function. WTH.
Looks interesting, but it too _requires_ a cloud account to function. WTH.
Thanks for pointing that out. I would love to have regular automatic BP measurements but not with closed source software that demands an internet connection.
> And goes without saying, your blood pressure SHOULD go up and down based on your activity and time of day. You just aren't used to seeing it other than at true rest.
Yeah, people panic reading a single 150 systolic, yet routinely it can reach 220+ during heavy exercise. It's perfectly fine. The health metric is the BP at rest, i.e. how low it goes when you're completely idle.
I find it takes up to 20 minutes to reach its lowest sometimes, in state of absolute calm: no movement, no talking, no anxiety. Hence the 'white collar hypertension', i.e. high BP when measured in hospitals and GPs office, where they don't give you enough time to settle down, or are not spaces that induce calm mental states.
The way I take my BP reading is every 5 minutes, until I get a similar reading after 2 consecutive measurements. It takes longer than you'd expect.
Yeah, people panic reading a single 150 systolic, yet routinely it can reach 220+ during heavy exercise. It's perfectly fine. The health metric is the BP at rest, i.e. how low it goes when you're completely idle.
I find it takes up to 20 minutes to reach its lowest sometimes, in state of absolute calm: no movement, no talking, no anxiety. Hence the 'white collar hypertension', i.e. high BP when measured in hospitals and GPs office, where they don't give you enough time to settle down, or are not spaces that induce calm mental states.
The way I take my BP reading is every 5 minutes, until I get a similar reading after 2 consecutive measurements. It takes longer than you'd expect.
100% hard agree. I'm now paying most attention to my overnight rate, like in the middle of the night - but even that takes a few hours to get down to the minimum value. Fascinating to see the big spike prior to waking up that signals your body is preparing for rising.
Did I eat late before bed? Higher BP overnight. Drink any alcohol at all after, say, 12pm? Higher BP overnight. So it's still useful and interesting to see the overnight values change and shift around.
However, the contrarian in my mind says that it's not smart to ONLY pay attention to your deep rest state BP, since that only applies to a fraction of the day. And if you're running around at high values for the rest of the day, you're still potentially doing damage to your kidneys, retinas, etc - the sensitive blood vessel stuff.
So it's a useful device, it's useful to have the data, but it's also still a bit of black box.
The fact that 80% of all high blood pressure is of unknown physiological cause is a real head scratcher considering that cardiac misadventures are the leading cause of death in the Western world.
Did I eat late before bed? Higher BP overnight. Drink any alcohol at all after, say, 12pm? Higher BP overnight. So it's still useful and interesting to see the overnight values change and shift around.
However, the contrarian in my mind says that it's not smart to ONLY pay attention to your deep rest state BP, since that only applies to a fraction of the day. And if you're running around at high values for the rest of the day, you're still potentially doing damage to your kidneys, retinas, etc - the sensitive blood vessel stuff.
So it's a useful device, it's useful to have the data, but it's also still a bit of black box.
The fact that 80% of all high blood pressure is of unknown physiological cause is a real head scratcher considering that cardiac misadventures are the leading cause of death in the Western world.
The cause is actually known: high amounts of fructose or sugar (which is 50% fructose) -> decrease in nitric oxide production in the liver -> high BP
Like many things, it is diet related. It seems "unknown" because GPs are still lagging well behind modern dietary research and are often nothing more than pill pushers. Lowering your sugar and simple carb intake over the long term, and fixing potentially hidden metabolic syndrome (see skinny fat people with unhealthy livers) is how you reverse it.
Like many things, it is diet related. It seems "unknown" because GPs are still lagging well behind modern dietary research and are often nothing more than pill pushers. Lowering your sugar and simple carb intake over the long term, and fixing potentially hidden metabolic syndrome (see skinny fat people with unhealthy livers) is how you reverse it.
Hey I hear you, appreciate the perspective but I'm borderline keto most days -- almost zero sugar, very few carbs, etc -- and yet still here.
So while this may explain some amount (perhaps most?) of peoples idiopathic/essential HBP I doubt it's that simple.
"It's your potassium levels", "it's your homocysteine levels", "it's your fructose", "it's white-coat syndrome", "it's...." etc. Surely we're making progress but it's also not a silver bullet thing.
Good thing the treatments are so safe and effective.
So while this may explain some amount (perhaps most?) of peoples idiopathic/essential HBP I doubt it's that simple.
"It's your potassium levels", "it's your homocysteine levels", "it's your fructose", "it's white-coat syndrome", "it's...." etc. Surely we're making progress but it's also not a silver bullet thing.
Good thing the treatments are so safe and effective.
During a recent visit, I mentioned my "White Coat Syndrome" was probably affecting me right there, so they selected their most attractive woman with the best perfume and a manual sphygmomanometer for a hands-on measurement, before releasing me.
I'm a med device engineer and have watched the hopes and dreams of cuffless BP monitoring tech. I hope we get there as it will be hugely important. However, remember tech is only a small part of the battle. We need to figure out clinically what to do with all this new continuous data.
I am very sceptical PPG alone will be capable for many reasons. Aktiia does indeed have European regs clearance. But, they don't have FDA clearance. The FDA is a very different beast (more hands on - and they'll be absolutely much more heavy with such a new approach) - and they must have concerns on the approach for it to take this long. The FDA even has accelerated programmes for breakthrough high impact tech as they really do want it to get to market safely.
The main cuffless FDA cleared devices I know measure the pulse transit time betwen a central ECG patch and a peripheral based PPG (that time is then calibrated to a BP with the Moens Kourteweg equation) - see Biobeats watch and a now defunct wearable ICU monitor company I can't find the name of.
The issue with PPG is that it is wildly sensitive. The PPG waveform morphology will changed dramatically based on the pressure of the sensor against the skin, unconstrained changes in orientation of the human and arm etc. Changes in morphology != changes in system wide BP.
Speak to an anaesthesiologist and they'll tell you blood pressure is function many things eg cardiac output, stroke volume, heart rate, blood volume, total peripheral resistance etc etc (https://www.sharinginhealth.ca/multimedia/images/blood_press...). The question is whether PPG alone can measure all these things. I suspect it's really just measuring lots of proxies of all these things. And that's fine - however in the presence of people with conditions or on therapeutics that alter these in very personalised and unpredictable ways then error may start to creep in on free living measurement. Paradoxically, it's probably these people for whom this tech would have most impact - not the worried well.
I am very sceptical PPG alone will be capable for many reasons. Aktiia does indeed have European regs clearance. But, they don't have FDA clearance. The FDA is a very different beast (more hands on - and they'll be absolutely much more heavy with such a new approach) - and they must have concerns on the approach for it to take this long. The FDA even has accelerated programmes for breakthrough high impact tech as they really do want it to get to market safely.
The main cuffless FDA cleared devices I know measure the pulse transit time betwen a central ECG patch and a peripheral based PPG (that time is then calibrated to a BP with the Moens Kourteweg equation) - see Biobeats watch and a now defunct wearable ICU monitor company I can't find the name of.
The issue with PPG is that it is wildly sensitive. The PPG waveform morphology will changed dramatically based on the pressure of the sensor against the skin, unconstrained changes in orientation of the human and arm etc. Changes in morphology != changes in system wide BP.
Speak to an anaesthesiologist and they'll tell you blood pressure is function many things eg cardiac output, stroke volume, heart rate, blood volume, total peripheral resistance etc etc (https://www.sharinginhealth.ca/multimedia/images/blood_press...). The question is whether PPG alone can measure all these things. I suspect it's really just measuring lots of proxies of all these things. And that's fine - however in the presence of people with conditions or on therapeutics that alter these in very personalised and unpredictable ways then error may start to creep in on free living measurement. Paradoxically, it's probably these people for whom this tech would have most impact - not the worried well.
I wonder if you've heard of the Resonance Sonomanometry method claimed by Esperto Medical https://esperto.health/ and how you think this compares to others.
It seems like it might be an ultrasonic method? They claim no calibration needed, but I don't know if it is tolerant to movement and posture.
I can also imagine this might be too power intensive to put in a smartwatch form factor. Maybe more of a bedside or clinical device...
Disclaimer: I had past contact with some of their researchers in a different bioimaging domain. I don't know anything more about this venture than it says on the website.
It seems like it might be an ultrasonic method? They claim no calibration needed, but I don't know if it is tolerant to movement and posture.
I can also imagine this might be too power intensive to put in a smartwatch form factor. Maybe more of a bedside or clinical device...
Disclaimer: I had past contact with some of their researchers in a different bioimaging domain. I don't know anything more about this venture than it says on the website.
I take it you had a good opinion of their researchers…
Plus gold standard measurements (ABP) are invasive enough that they're not used often for studies. Much of our available data comes from surgeries and a handful of dead dogs.
I'm hoping someone can answer a question that's been bugging me for years: When I take blood pressure medication my blood pressure goes down but my heart rate goes up[1]. That can't be good. Heart rate has a strong inverse correlation with lifespan, and this even holds across species (animals with higher heart rates have shorter lifespans). So does lowering blood pressure reduce the risk of heart disease, stroke, etc, but nevertheless shorten your lifespan in other ways because of a higher heart rate?
[1] I've verified this for myself with careful record keeping over long periods of starting/stopping different BP meds, but I'm not entirely sure it's true for everyone.
[1] I've verified this for myself with careful record keeping over long periods of starting/stopping different BP meds, but I'm not entirely sure it's true for everyone.
This sounds like reflex tachycardia -- your body wants to ensure blood is flowing to all the right places, so it raises heart rate to partially compensate for blood pressure falling. Reflex tachycardia can be a normal response to certain types of blood pressure medications, like vasodilators or diuretics. Beta blockers are a different common type of blood pressure medication that attempt to lower both blood pressure and heart rate simultaneously.
If the increase in heart rate is large (>30bpm), especially when going from laying to standing, it could be a sign of underlying dysautonomia or POTS. If you experience symptoms (dizziness, fatigue, fainting, etc) it's worth getting evaluated. We (the OP) do offer medical care for POTS here: https://empirical.health/pots
As for the relationship between low heart rate and longer life spans, it's not necessarily causal -- a lower heart rate is often a sign of a stronger cardiac muscle (each beat pumps more blood, so fewer beats per minute are required to pump the same volume of blood). So I'd suspect much of the relationship here is driven by these confounding variables!
If the increase in heart rate is large (>30bpm), especially when going from laying to standing, it could be a sign of underlying dysautonomia or POTS. If you experience symptoms (dizziness, fatigue, fainting, etc) it's worth getting evaluated. We (the OP) do offer medical care for POTS here: https://empirical.health/pots
As for the relationship between low heart rate and longer life spans, it's not necessarily causal -- a lower heart rate is often a sign of a stronger cardiac muscle (each beat pumps more blood, so fewer beats per minute are required to pump the same volume of blood). So I'd suspect much of the relationship here is driven by these confounding variables!
I won’t be a user of your service, but wanted to share a bit of feedback on the page you shared. On that page, I didn’t see any definition for POTS (though I know what it is or if I were someone else, I could’ve searched online). The page mentions a CHOP protocol without a link or explanation about what it is. I think the page could do better with some simple explanations or at least a guidance on symptoms and what you offer. Currently it seems like it’s optimized to be linked for anyone searching for POTS, which probably assume a lot more than what most people may be aware of.
You're absolutely right. This page was originally written for people searching for POTS, so we assumed some context. I've updated the page to link to pages we've written on POTS diagnosis and the CHOP protocol, so that it stands alone a bit more.
Let me second your comment. That webpage really needs to define POTS and give a brief explanation. It's written as if everyone knows what it is. I've never encountered the term Postural Orthostatic Tachycardia Syndrome until now.
Thanks! Mentioned above -- I updated the page to link to dedicated articles on each of these.
It’s pretty normal for heart rate to increase with a drop in blood pressure. It’s part of a normal reflex called the baroreceptor reflex that your body evolved to keep you alive.
To answer your question, there have been an abundance of epidemiological studies showing that the drop in blood pressure is worth the slightly increased heart rate (assuming you’ve been diagnosed with hypertension). The main benefit is the drop in stroke risk, atherosclerosis, and kidney damage, even despite the fact that your heart has to beat faster.
To answer your question, there have been an abundance of epidemiological studies showing that the drop in blood pressure is worth the slightly increased heart rate (assuming you’ve been diagnosed with hypertension). The main benefit is the drop in stroke risk, atherosclerosis, and kidney damage, even despite the fact that your heart has to beat faster.
My understanding of the heart rate correlation to lifespan between different species is that it is “within a couple levels of magnitude” and that an increase of 10% in a human’s rate does not correlate at all to a 10% decrease in lifespan
I'm not a doctor, but my understanding is that lower blood pressure can indeed lead to a higher heart rate under certain circumstances. For instance, people taking minoxidil for hair loss can experience lower blood pressure, which leads to higher heart rates and increased left ventricle thickness as a side effect.
My suspicion is that this happens because the heart is trying to maintain a constant oxygen supply to the muscles. However, if blood pressure is lowered by improving factors like arterial flexibility, stroke volume (amount of blood per heartbeat), muscle oxygen efficiency, or oxygen content in the blood, the heart wouldn't need to pump faster.
My suspicion is that this happens because the heart is trying to maintain a constant oxygen supply to the muscles. However, if blood pressure is lowered by improving factors like arterial flexibility, stroke volume (amount of blood per heartbeat), muscle oxygen efficiency, or oxygen content in the blood, the heart wouldn't need to pump faster.
It's the futility of trying to make two arbitrary numbers go down and covering up a mere symptom.
Hypertension is correlated with a lot of issues, and it's easy to measure.
It's also easy to keep formulating novel chemicals, so keep complaining about side effects, and your physician will be happy to keep spinning the Formulary Roulette Wheel.
Hypertension is correlated with a lot of issues, and it's easy to measure.
It's also easy to keep formulating novel chemicals, so keep complaining about side effects, and your physician will be happy to keep spinning the Formulary Roulette Wheel.
It’s complicated. You need blood pressure to live…
Too low heart rate can also be a problem.
talk to your cardiologist about your specifics.
At the population level, the guidelines have backed off over the last 20 years. What’s normal now used to be called high blood pressure.
Too low heart rate can also be a problem.
talk to your cardiologist about your specifics.
At the population level, the guidelines have backed off over the last 20 years. What’s normal now used to be called high blood pressure.
> Heart rate has a strong inverse correlation with lifespan, and this even holds across species (animals with higher heart rates have shorter lifespans).
I’m not a doctor, but I don’t think this covers all cases. If someone has some kind of heart disease, they could have a lower resting heart rate and probably need medical attention and care. It may not imply that they’re going to live longer.
I’m not a doctor, but I don’t think this covers all cases. If someone has some kind of heart disease, they could have a lower resting heart rate and probably need medical attention and care. It may not imply that they’re going to live longer.
Have you mentioned this to your doctor? There are different types of blood pressure medications. Some will lower your heart rate.
Back when I took beta blockers they reduced my heart rate from 65-70 to 45-55.
Back when I took beta blockers they reduced my heart rate from 65-70 to 45-55.
Tangentially Related: https://arstechnica.com/health/2024/10/your-doctors-office-c...
Yeah -- in addition to inappropriate measurement technique, "white coat hypertension" can cause elevated blood pressure readings.
And, of course, you have the fact that the American College of Cardiology (ACC) updated their blood pressure guidelines in 2017 to use a lower threshold. So some people with moderately high blood pressure would now be considered to have hypertension and are recommended to seek treatment.
And, of course, you have the fact that the American College of Cardiology (ACC) updated their blood pressure guidelines in 2017 to use a lower threshold. So some people with moderately high blood pressure would now be considered to have hypertension and are recommended to seek treatment.
The threshold was 160. Then 140, then in 2017 130 so suddenly millions of new people whom were fine the day before now have a hypertensive crisis and need to be prescribed pharmaceuticals for the rest of their lives. The profit arising from this change is just a happy coincidence arising from the evidence.
Measuring blood pressure on the wrist is tricky. I usually do three measurements to get an accurate reading. I have two machines I use. The older one is actually better than the new one. Another thing is, pay attention to how you feel. I can feel my blood pressure when it's high and usually know when the device reading is off. I do this because my family has a history of high blood pressure and so far because of lifestyle choices I have avoided the need for meds.
Why do you have to do it so often? Why do you even do it if you’re not on meds? Third, what would you even do if it’s high?
I don't check my blood pressure every day. Maybe twice a month or when I feel like crap. I also check my glucose. Why? I believe if I keep myself in check I will keep myself out of the hospital as I age. High blood pressure and diabetes are two things I can manage. I don't want to be on meds unless I absolutely have to. Exercise and these tools allow me to figure out what I can eat and not. I'm not obsessed with my health or a health "nut". The upside is I don't get sick that much and feel good.
What are some examples of the non-pharmacological/lifestyle approaches you’ve taken?
I would love to have continuous BP monitoring. I ready for this tech to mature. I'd wager that blood pressure varies way more during the day than weight (which can vary as much as 5 lbs or more) - and continuous, easy BP monitoring at would cause HT dxs to drop significantly.
High blood pressure has been defined as blood pressure over a certain threshold when blood pressure is taken a certain way. That certain way is at rest when it's lower than moving around. All the data and research has correlated health outcomes that way. We already know blood pressure is higher when you are up and about than after you've been sitting down for 5 minutes. If you're trying to get out of your hypertension diagnosis using continuous monitoring you are in for disappointment because hypertension has been defined by your blood pressure when it's at its lowest.
If you look at the BP measurement protocol for HT dx, most people will never have a visit that matches that protocol because it costs a lot of time and time is something medical practices don't like to give for something as simple as HT dx.
https://www.ahajournals.org/doi/pdf/10.1161/HYPERTENSIONAHA....
24 hour ambulatory BP measurements are the gold standard for accurate HT dxs.
https://www.ahajournals.org/doi/pdf/10.1161/HYPERTENSIONAHA....
24 hour ambulatory BP measurements are the gold standard for accurate HT dxs.
Well, baked into your own claim, they don't have hypertension if their pressure is only elevated when it's taken (e.g. the doctor's office) rather than what it might drop to otherwise.
I have a blood pressure monitor that takes the lowest of three measurements. It's really annoying to use, takes forever, feels uncomfortable, and my blood pressure often drops another 10 points if I do it all over again because I've been laying in the bed another 5min.
Passive measurements address all of this. You also get to see what activities have what impact on your blood pressure. How does your daily blood pressure graph look like on and off ADHD meds, for example?
I can't wait until this info is part of the wrist wearable kit.
I have a blood pressure monitor that takes the lowest of three measurements. It's really annoying to use, takes forever, feels uncomfortable, and my blood pressure often drops another 10 points if I do it all over again because I've been laying in the bed another 5min.
Passive measurements address all of this. You also get to see what activities have what impact on your blood pressure. How does your daily blood pressure graph look like on and off ADHD meds, for example?
I can't wait until this info is part of the wrist wearable kit.
The problem with this is exercise messes with blood pressure.
“Extremely high blood pressure elevations of up to 345/245 mmHg were observed during the lifts.”[1]
My doc even said it can get as high as 400 and it’s important to breathe correctly.
[1]https://pubmed.ncbi.nlm.nih.gov/2632751/
“Extremely high blood pressure elevations of up to 345/245 mmHg were observed during the lifts.”[1]
My doc even said it can get as high as 400 and it’s important to breathe correctly.
[1]https://pubmed.ncbi.nlm.nih.gov/2632751/
Yes, BP is much higher when exercising, but presumably in these situations the user will indicate that they are exercising in whatever app they are syncing with. 24 hour ambulatory BP measurement protocol directs pts to not exercise during the time to rule out this confounding factor.
What we really need is a device that can be implanted in our bodies, and which will measure BP, blood sugar, heart rate, and various other factors, so that this data can be collected by our physician and analyzed to see if we have any health issues well before bigger problems arise.
> HT dxs
I'm unfamiliar with this abbreviation but did my best with Google. Does it mean 'hypertension diagnoses'?
I'm unfamiliar with this abbreviation but did my best with Google. Does it mean 'hypertension diagnoses'?
yes
Why do you think this would cause HT diagnosis to drop? If anything all of these continuous monitors create more patient visits and probably more diagnosis.
I'm interested in what the future holds when these things are capable of FDA-approved diagnosing. Will Apple send a prescription for BP meds to my pharmacy?
I'm interested in what the future holds when these things are capable of FDA-approved diagnosing. Will Apple send a prescription for BP meds to my pharmacy?
I think there is a lot of white coat HT that makes up many cases. I think the ACS recommends a measurement 3 times in a row at different office visits. So, maybe anxiety might be a direct cause of HT dx.
For anyone interested in on-the-wrist blood pressure tracking who doesn't want to spend the money on a Samsung Galaxy and hack SHMs, or wait for Apple to implement it, there are a plethora of Chinese smartwatches that already have the blood pressure monitoring and calibration capability that can be had for < $15.
My experience with them is that although I wouldn't trust these to diagnose a medical condition, the trends are correct and correlate to cuff readings - they're not just random number generators.
I just wish there were a way to export the data from the H Band app. Apparently, the data is stored in SQLite files.
My experience with them is that although I wouldn't trust these to diagnose a medical condition, the trends are correct and correlate to cuff readings - they're not just random number generators.
I just wish there were a way to export the data from the H Band app. Apparently, the data is stored in SQLite files.
> there are a plethora of Chinese smartwatches that already have the blood pressure monitoring and calibration capability that can be had for < $15
Sounds interesting. Any idea where can I find such, and additionally, how I can differentiate from the ones with fake claims?
Sounds interesting. Any idea where can I find such, and additionally, how I can differentiate from the ones with fake claims?
I am fascinated by the concept of blood pressure as one of the foremost tools of health. Can someone recommend perhaps a book size read on the history of how we came to learn of its value and help illuminate well... what it even is?
For most instruments, it's an interplay between resolution and consistency. There isn't a "true" reading in any sense of the word. There is just how much resolution you are measuring and how consistent the measurement is between independent readings of the same event.
The overwhelming amount of pre-existing clinical data gathered by cuff-monitors means that any novel measurement methods benefit from tying/correlating their output to the existing data for compatibility. It's a bit unfortunate in some sense as cuff-monitor data lacks resolution and sometimes can be a bit of a drag on novelty.
The overwhelming amount of pre-existing clinical data gathered by cuff-monitors means that any novel measurement methods benefit from tying/correlating their output to the existing data for compatibility. It's a bit unfortunate in some sense as cuff-monitor data lacks resolution and sometimes can be a bit of a drag on novelty.
Two tidbits from me:
Several years ago, I got an omron wrist cuff blood pressure monitor. Some doctors showed heavy skepticism at the time but I've never seen any reason to think it's inaccurate when properly mounted and with healthy batteries.
I had a sleep study done last year using a brand new machine the lab got (literally unboxed while I was there) that uses a combination of the ecg signals and pulse timing to calculate blood pressure continuously once calibrated. Seemed pretty cool to me and I got the impression this technique is fairly new?
Several years ago, I got an omron wrist cuff blood pressure monitor. Some doctors showed heavy skepticism at the time but I've never seen any reason to think it's inaccurate when properly mounted and with healthy batteries.
I had a sleep study done last year using a brand new machine the lab got (literally unboxed while I was there) that uses a combination of the ecg signals and pulse timing to calculate blood pressure continuously once calibrated. Seemed pretty cool to me and I got the impression this technique is fairly new?
I guess that "properly mounted" may be a problem for a lot of people. According to operating manual measurements should be taken at heart level with 30±5 cm distance between top of the seat and top of the table. Outside of that ±5 cm difference you may get inaccurate results.
I've an arm cuff monitor but recently bought a wrist one, both Omron, because my wife didn't like the arm cuff.
What I found was the wrist cuff was incredibly sensitive to both positioning and to any movement, it was harder to get a consistent reading.
What I found was the wrist cuff was incredibly sensitive to both positioning and to any movement, it was harder to get a consistent reading.
Hypertension is more dangerous than smoking, I read - as I was shocked to discover I had let it slide massively at my last attempt to donate blood at Australia Red Cross.
Fast forward 9 months, and I'm now using my Galaxy Ultra watch to monitor my blood pressure, and I've been able to reverse hyper tension thanks in part to how much of an improvement it has made when it comes to quickly getting the pressure reading.
Compared to the Omron I calibrate it against, it's a far better experience. It's also a huge step up in performance over the 6 Classic that I upgraded from. That one would have a failed reading 3 times out of 4, whereas the Ultra gets it right just about every single time.
The biggest pain is the monthly calibration process, seriously it feels like if I bat an eyelid, or not have the cuff on with just the right tightness, or just have the arm at a slightly different angle, or just get anxious about this whole thing, the Omron (a modern unit with built in Bluetooth etc) will give a different reading. When I get the process done right, however, the Galaxy will return readings that are very close to the Omron both systolic and diastolic - and then it's a month until next time.
Being able to quickly and easily get my blood pressure in a number of different situations made a huge change in my motivation to get it under control; I primarily focused on diet and exercise. I ran/run the test several times per day, and learned so much from it. Absolutely love my Ultra watch, it looks gorgeous and performs amazing in general as well.
Fwiw I'd regularly see values like 140-155 over 90, now I'm typically around 120 over 80 give or take.
Fast forward 9 months, and I'm now using my Galaxy Ultra watch to monitor my blood pressure, and I've been able to reverse hyper tension thanks in part to how much of an improvement it has made when it comes to quickly getting the pressure reading.
Compared to the Omron I calibrate it against, it's a far better experience. It's also a huge step up in performance over the 6 Classic that I upgraded from. That one would have a failed reading 3 times out of 4, whereas the Ultra gets it right just about every single time.
The biggest pain is the monthly calibration process, seriously it feels like if I bat an eyelid, or not have the cuff on with just the right tightness, or just have the arm at a slightly different angle, or just get anxious about this whole thing, the Omron (a modern unit with built in Bluetooth etc) will give a different reading. When I get the process done right, however, the Galaxy will return readings that are very close to the Omron both systolic and diastolic - and then it's a month until next time.
Being able to quickly and easily get my blood pressure in a number of different situations made a huge change in my motivation to get it under control; I primarily focused on diet and exercise. I ran/run the test several times per day, and learned so much from it. Absolutely love my Ultra watch, it looks gorgeous and performs amazing in general as well.
Fwiw I'd regularly see values like 140-155 over 90, now I'm typically around 120 over 80 give or take.
Side note, I started monitoring with a cuff-style monitor over the past month, and one thing that’s super important is keeping the cuff at about heart level. The cuff I got actually reminds you of this verbally. While it obviously makes sense, it’s a bit surprising how much a change in elevation affects the readings.
Try sticking it around your ankle and measuring while standing up. I get 250 mmHg systolic, easily
How long does calibrating an on-the-wrist sensor take with a cuff?
I used to work at Higi which has many blood pressure cuffs in public locations. I'm wondering if it's practical to calibrate a smartwatch sensor at one of these, or if it would take too long when you're grocery shopping or at the pharmacy.
I'm also wondering if new generation cuffs are required. The cuffs we used would be pretty old at this point.
I used to work at Higi which has many blood pressure cuffs in public locations. I'm wondering if it's practical to calibrate a smartwatch sensor at one of these, or if it would take too long when you're grocery shopping or at the pharmacy.
I'm also wondering if new generation cuffs are required. The cuffs we used would be pretty old at this point.
Now I'm wondering how well calibrated those automatic public cuffs are in the first place...
Haven’t read the article yet but there are three big things that hinder the usefulness of this tech as it stands:
1. Most clearances only apply to when people are motionless. 2. Often need to calibrate frequently. 3. No practitioner knows what to do with continuous bp data even if they had it.
Solve those and we’ve got something big. Until then progress is welcome but not revolutionary.
1. Most clearances only apply to when people are motionless. 2. Often need to calibrate frequently. 3. No practitioner knows what to do with continuous bp data even if they had it.
Solve those and we’ve got something big. Until then progress is welcome but not revolutionary.
I got a Xiaomi GT3 watch for less than 40$ including shipping. it has blood pressure measuring. How accurate? I dont know. I have a normal BP, and it always shows me normal values. Whe I try it on my son or wife's wrist, it always measures a lower BP.
Anyways, I stopped looking at it, and I only use it for the looks and to show me notifications.
Anyways, I stopped looking at it, and I only use it for the looks and to show me notifications.
I've got a dubious watch bought from AliExpress that was even cheaper and that claims to monitor blood pressure as well as blood glucose levels, blood lipids and even uric acid levels (that's why I bought it as I get gout). It's obviously not going to be calibrated and accurate, and I did get my brother (who's Type 1 diabetic) to compare the watch readings with his own glucose measurement and it was over 10% out, but that could also be a timing issue as he had just recently eaten. Definitely not a device that you would use to determine insulin injections.
Have you considered comparing it to a regular blood pressure monitor in parallel? My guess is that since it isn't certified as a medical device, it's essentially just a random number generator. No smart watch from a big name brand offers this feature yet, so I doubt a $40 device has figured it out.
Great read.
Side note: please fix your header. Makes the website appear so much less professional than the information it provides really is.
Side note: please fix your header. Makes the website appear so much less professional than the information it provides really is.
Thanks! Would you be able to send me a screenshot of what you're seeing? It may be formatting differently on your screen than mine. [email protected].
What's currently the best in the market wearable (watch, ring or maybe something else) to track (useful) health indicators?
If Apple ever gets continuous bp or glucose monitoring I will probably start to wear one.
I've dabbled a bit with it and it's very close to the cuff measurements.
It works by calibrating with their custom arm cuff device. I'd guess that it's correlating what the wrist sensor sees w.r.t. your wrist blood vessels and what the "true" reading is from your arm. You re-do the calibration every few weeks.
The device takes a reading every 20 or 30 minutes or so and seems to try to pick periods where you're more stationary.
However, one thing to be aware of is that you are not used to seeing your BP readings from the entire day. Did you jump in a cold plunge 10 minutes before it ran? Get ready to see a really high reading dot in the 'danger zone'. Went for a jog and are catching your breath on a park bench? High dot.
This isn't a bad thing, it just takes some getting used to since your "daily average" will be significantly above the readings you're used to if you're doing arm cuff measurements at the start/end of the day. Of course it's also getting readings at those more usual times too, but they get washed out in the larger number of data points from your day.
And goes without saying, your blood pressure SHOULD go up and down based on your activity and time of day. You just aren't used to seeing it other than at true rest.
But all in all it's been fascinating to see, and there's no doubt in my mind that this technology will be mainstream quickly (and Apple will likely dominate it).