> 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.

> 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.

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.

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'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.

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.

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?

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

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.

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)

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.

What extra useful information can you get from continuous BP measurement compared to once or twice daily measurement?

> Aktiia

Looks interesting, but it too _requires_ a cloud account to function. WTH.

> 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.

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.

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.

Sotera Wireless

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!

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.

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.

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.

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.

> 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.

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.

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.

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?

What are some examples of the non-pharmacological/lifestyle approaches you’ve taken?

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.

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/

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'?

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?

> 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?

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.

Try sticking it around your ankle and measuring while standing up. I get 250 mmHg systolic, easily

Now I'm wondering how well calibrated those automatic public cuffs are in the first place...

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.

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. bmb@empirical.health.