Aktiia bracelet review: cuff-like blood pressure monitoring from the wrist
- Works with cuff-like accuracy
- Automatic measurements
- Low-key design
- Simple to use app
- Good battery life
- Only measures blood pressure & resting heart rate
- Little in terms of insights (this will change with future updates)
We are edging closer to the day when blood pressure monitoring from the wrist will be a normal thing. It might happen later this year, more likely in mid-to-late 2022 and beyond.
One of the first real entrants in this market is Swiss startup Aktiia. The outfit has just started selling its wrist-based optical blood pressure monitor (BMP) in the UK (view on aktiia.com). From early May, availability will be extended to Germany, Austria, France and Switzerland. This will be followed by the US in the near future, once FDA approval is secured.
Essential reading: Best fitness trackers and health gadgets
Many adults are affected by hypertension, but as many as one in three can be unaware they have the condition. They feel the odd twinge or headache, but simply put this down to feeling a little under the weather. And this is the paradox and the reason high blood pressure is sometimes called the silent killer. You don’t know you have a problem until it’s too late.
Home BPMs can be quite useful. Taking regular measurements is particularly important as you get older – the effects of an unhealthy lifestyle tend to build up over time.
Whether they are smart or traditional, BPMs typically come in one of two forms – those for the upper arm, and those for the wrist. Nearly all of these use some type of inflatable cuff technology.
We have yet to see a big brand come up with a wrist wearable that utilizes optical sensors to measure blood pressure with cuff-like accuracy. There is lots of stirring in this area, though.
Samsung is perhaps taking the lead with its Galaxy series. However, these measurements are not on par with cuff like accuracy. Fitbit has also just announced a study on whether its Sense smartwatch can take such readings.
Part of the problem is that the wrist arteries are narrower and not as deep under your skin as those of the forearm. Which makes taking blood pressure from that location more difficult.
There is, of course, the Omron HeartGuide. But this is a watch-sized sphygmanometer so does not use optical sensors. It’s basically a miniature cuff that is built into a smartwatch. Omron has filed more than 80 patents to create the thing a couple of years ago.
Which leaves us with traditional BPMs. They work well but many of us do not use them on a regular basis.
The Aktiia bracelet promises something never seen before. Automatic, clinically validated blood pressure measurements during the day and night taken from the wrist with optical sensors. No buttons to press, nothing to do except wear it.
Does it work as advertised? I’ve been living with the Aktiia bracelet for nearly a month. Read on to find out what I made of it. Also worth a read is my interview with Aktiia CEO, Micheal Kisch.
Design and hardware
Setup and use
Results, app, summary report
Aktiia bracelet review: Design and hardware
- discreet design
- no display, app shows data
- uses optical heart rate sensor & proprietary algorithms
- 9 day battery life
In the box the Aktiia system comes with the measuring bracelet, a traditional blood pressure cuff, charging cables and a small charging stand. There’s also a little instruction booklet if you care to read it. I typically dive straight in without spending much time on literature. Luckily the information in the smartphone app was sufficient to guide me through setup and use.
What surprised me a bit, though, was that there was an Aktiia-branded traditional cuff in the box. You’ll discover on initial setup that you do need to calibrate the device before first use, and then once per month. Not a big deal but something to be aware of.
The bracelet itself is very low key. It consists of a core unit made of metal attached to a velcro strap. The band slots through two rings on the main unit and is secured in place via a traditional watch buckle. Once on there’s no danger whatsoever of it falling off.
This is a one size fits all affair. But the strap is adjustable so can fit a variety of wrist sizes, 14 to 21 cm. The same is the case with the initialisation cuff. Aktiia says the cuff can accommodate arms with a circumference between 22 and 42 cm. That’s most people.
What I really liked is the small form factor of the Aktiia bracelet. The thing is not a substitute for a traditional activity band. It only captures blood pressure readings and resting heart rate. So if you have a fitness tracker and smartwatch that you use on a daily basis, the minimalistic design of Aktiia means you can wear it on the other wrist. Some might even mistake it for a piece of jewlery.
Under the hood
As far as the underlying technology, the Aktiia system uses common optical heart rate sensors and proprietary algorithms to measure an individual’s blood pressure at the wrist. The system works by analyzing the changing diameter of the arteries with each heartbeat. The monitoring is performed at regular intervals automatically, so users can see how their blood pressure changes at different times of the day and night.
The wearable has a battery life of 9 days so does not need charging often. Simply wear it as you would any fitness tracker and go about your day.
You do need to take it off, though, when taking a bath or going for a swim. That’s because the bracelet is only splash-proof. Keeping it on for a swim would be kind of pointless, anyway. Aktiia takes measurements only during rest periods. It will take readings when you are lying in bed and perhaps at times when you have been sitting down for a while.
After about a week, I found myself taking it off when I would head out the door. I did that in the knowledge that I won’t really be missing out on any data. Capturing blood pressure while you are walking or exercising is useless – even with a traditional measuring cuff.
To this end, the Aktiia bracelet has an accelerometer inside. But this is not to count your steps or calories burned. It’s to figure out if you are stationary. By gauging movement, the bracelet can assess when accurate measurements can be taken.
Aktiia bracelet review: Setup and use
- readings are captured automatically
- works while you are at rest
- requires calibration once per month
Before first use you’ll need to calibrate the band with a traditional blood pressure cuff. As mentioned, this is included in the box.
The calibration is done via the Aktiia smartphone app. This will take you through a brief setup procedure. You’ll also be guided on the correct way to wear the bracelet. The instructions say the band should be snug but not too tight. They suggest leaving enough space for a pencil to slide through between the strap and your wrist.
I followed the instructions to the letter. In the end I found that it’s actually better to keep the strap close-fitting as it captures readings more frequently. So if the device fails to register measurements often enough, try tightening the band. Ensuring, of course, that there’s still a comfortable fit.
The app will also help you calibrate the device. With the Aktiia bracelet and the traditional cuff on, you’ll need to capture readings from both at the same time while being in a seated, comfortable position. Two individual readings will be taken one after the other to ensure accuracy.
The process can be a little finicky and requires a bit of trial and error. It took me about 5 minutes to perform the calibration the first time. For some reason the band worked much better from my right wrist than my left wrist. To make sure all was ok I did a few more calibrations. On subsequent tries it was much easier and worked flawlessly.
Aktiia says the bracelet should be recalibrated at least once a month. Rather usefully, the app shows the date by which you need to do the next calibraiton.
If the initialisation is not performed within the required date, accuracy cannot be ensured. This is the reason the company displays a disclaimer on the box. The data might not be accurate if the initialization is not performed in due time.
After setup and calibration you are good to go. The small form factor of the Aktiia bracelet coupled with the fact that it’s very light means you’ll quickly forget you are wearing it. In this sense, I think it actually helps that the wearable doesn’t have a display. Just make sure you charge the bracelet every week or so.
Aktiia bracelet review: Results, app, summary report
- readings can only be seen in the app
- daily, weekly, month trends
- PDF summary report
The results can be viewed in the accompanying smartphone app. This allows you to see individual readings, averages and share a summary report with others.
As with all such devices, a sync is performed via a Bluetooth connection. This typically takes less than a minute.
The app itself is a rather simple affair. There are three tabs along the bottom. The Home tab is where your blood pressure readings sit. Next to it is the Devices tab where you can view battery level of both the bracelet and cuff. The final tab shows your Profile and settings.
Readings can be viewed and charted on a daily, weekly and monthly basis. I estimate that on average the bracelet would take 9-10 measurements per day.
What’s most important is that these readings meet the ISO81060-2 standard for accuracy. Hence, the wearable has the CE marking as a Class IIa medical device (for users within the age group 21-65, excluding contraindications due to certain health conditions). Lots of research went into creating the Aktiia system. This includes 5 clinical trials and 1 million measurements to date. You can read more about accuracy on this link.
I sometimes take blood pressure measurements in the morning with a traditional blood pressure cuff. The systolic and diastolic values would typically be about 8-10 points above the readings from Aktiia. Which makes sense. The Aktiia measurements are taken while you are asleep or at rest. I take readings with a traditional cuff in a sitting position during the day.
The app also collates averages. For me, the readings did not change very much from day to day. But they would go up or down by a couple of points. This would depend on my activity the previous day.
For example, if I did a particularly stressful bout of exercise, my readings would go slightly up during the night. Also, the week after a plane flight – the readings steadily fell each day as I recovered from the trip.
But you can see the potential. The fact that Aktiia works automatically 24/7 means you can experiment how changes in exercise, diet and sleep effect your cardiovascular health. The app will chart the measurements so you or your doctor can spot patterns.
What I would have liked to have seen is a bit more analysis. Apart from the daily, weekly and monthly averages, it ends with weekday vs weekend averages.
But this is on the company’s to-do list. According to Aktiia CEO, future software updates will bring insights such as day vs. night analysis, the ability to “label” the data so that the user and their physician better understand the specific impact of diet, exercise, medication and stress on their cardiovascular health and targeted heart health tips based upon each user’s unique blood pressure pattern.
Another useful part off the system is reports. You can generate a summary document for a set time period. This can then be viewed on your phone, downloaded as PDF or sent to your health care provider.
Here’s an example of the summary report. Click on the image below to enlarge.
Aktiia bracelet review: The verdict
The Aktiia bracelet is not meant as a replacement for a fitness band or smartwatch. It uses optical sensors to track blood pressure from the wrist, along with resting heart rate. Nothing else. But it does this with clinical-grade accuracy, automatically, multiple times during the day and night. At the moment, this is the only product of its kind.
The small form factor of the bracelet means you can put it on and forget about it. Just remember to charge it every week or so. And do the calibration with a traditional cuff once per month.
All in all, I found the Aktiia bracelet works very well. In a 24 hour period it would capture about 10 readings. This is all charted for you in the simple to use app, plus you can generate a report to share with your doctor. The readings were where I expected them to be. What adds confidence is the clinical validation and the fact that the wearable has the CE Mark clearance for accuracy.
The system is ideal for someone who wants to keep a closer eye on their cardiovascular health. It can also be useful for those that are at risk for or have already been diagnosed with high blood pressure. The wearable provides a great tool to help you make lifestyle changes that benefit your cardiovascular health.
The Aktiia bracelet can be purchased by those living in the UK. Other countries will follow soon. You can add your email to the waitlist on the website to be notified when Aktiia will be available in your country.
The bracelet costs £129.99 with an on-going £6.99 monthly subscriptions to access the Aktiia 24/7 Monitoring Service. The £199.99 annual plan includes the monthly subscription cost.
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19 thoughts on “Aktiia bracelet review: cuff-like blood pressure monitoring from the wrist”
I have been following this company for a while and was excited to see this product finally being brought to market. However, I was very disappointed to see that the watch needs to be calibrated with a cuff. This is not true cuffless technology, which is what I have been waiting for. Some people find that cuffs grip their arms tightly, which sends off alert singles to the brain, thus elevating blood pressure. This means that a normal reading isn’t obtained. Subsequently the very act of wearing a cuff can create anxiety, knowing that you’re going to get an inaccurate reading. The whole point of cuffless and continuous measurement is for there to be no interaction with a cuff at all. I would expect to be able to buy a blood pressure ‘watch’, wear it and forget that it is there. This way more accurate readings can be obtained.
It does not matter if your blood pressure elevates during the cuff measurement for Aktiia bracelet calibration, the only thing that matters is how well the numbers obtained by the cuff correspond to the numbers obtained by the bracelet! 🙂 You are completely wrong in your reasoning – calibration is needed for any device, I repeat – ANY device.
Totally agree. 👍👍
I really don’t see an issue here. The cuff is only needed one time in a month to calibrate absolute values with the bracelet. During this process the values just have to stay constant. Therefore you should try to relax and keep your blood pressure constant. In the remaining time the bracelet measures every hour at least one time the blood pressure and that quite reproducible compared to my old cuff.
And so it follows, that if there’s any issue with your calibration measurement, a whole months worth of bracelet measurements are going to be off as well. You would want to start increasing the calibration frequency to iron out potential giant mis steps in readings.
I read the “Clinical Trial” paper provided by Aktiia (on their site) relating to the accuracy of the bracelet in various body positions. Consider: an upper arm cuff, by it’s nature, will tend to be at more or less the right height (at heart level). Wrist cuffs, on the other hand, would tend not to be in the right place and so you are told to position your wrist at heart level for the reading.
I was trying to establish how Aktiia overcame this problem. How could a wrist positioned monitor work when you are standing up, or lying asleep with your arm hanging out of the bed and dragging on the ground. Or reclining on a couch watching TV with arm held over and behind your head? How could the bracelet know how far your wrist was above/below your heart and compensate.
Well maybe it can’t know.
The “Clinical Trial” paper doesn’t relate to an actual clinical trial. It relates to a pilot (a pilot is a precursor activity which aims to assist in the design of a clinical trial, the clinical trial being a much larger affair) and the authors of the pilot are Aktiia employees.
They note the fact that there is no protocol for validating wrist worn devices for measuring in multi body positions. With good reason perhaps: an upper arm cuff is likely to be in the right place, by the heart. But how, pray tell, could a wrist worn cuff/device compensate for the fact it might be miles from the heart?! How would it “know” how far above or below the heart it is?
In the discussion section of the “paper” the accuracy of the device is listed for various body positions:
supine (67% of readings were “accurate”. Or to put it another way: 37% of readings were not accurate)
sitting (50% of the readings were accurate. Or to put it another way..)
standing (25% of the readings were accurate. Or to put it another way)
25% accurate when standing? Or 75% inaccurate?
I recently bought one of these bands to monitor my BP after recent high blood pressure issues, but 3 days in and I am really disappointed and thinking of returning it as it’s next to useless in the real world.
Packaging – good.
App – good.
Hardware look and feel – good.
Price – good.
Actual function – unknown.
The issue I have is that it only takes measurements during ‘rest periods’, which are not well defined in the documentation. As such, over the last 3 days it has only taken measurements when I am asleep!
I have a deskjob which keeps me tied to a computer screen for 6+ hours per day, but I don’t get any measurements taken by the band. I have tried changing tightness, wearing it on my non-dominant wrist etc, but nothing works.
For me it is pretty useless to pay to have a measurement of BP at the times I don’t actually need it!
I think you’ll find its pointless taking blood pressure when you are not totally at rest. Traditional blood pressure monitors work in a similar way. You are meant to relax and sit still for 5 minutes before taking a reading with a traditional blood pressure monitor.
Having tested this over a month:
1. There is no sync with Apple Health which is fairly maddening for iOS users. There is no ability to export data at all.
2. The app is a bit buggy eg you cannot set the sleep time, it just reverts to a default when you do.
3. It’s giving very different readings to my Omron calibrated cuff. I’m really extremely doubtful it is accurate and their support site says “may” and “can” etc,
4. It was refused by my aviation medical examiner who said it was flawed because you have to be still, upright etc. I had to go and buy a “proper” one,
5. I did ask to return it but they refused saying the 14 days was up – despite it still being in the box. Reading between the lines I think they are dealing with a huge number of returns.
I think that this device has a great potential and indeed is the future way to measure blood pressure on an ongoing basis over the whole day. However, when comparing the measurements from the device and my own blood pressure monitor the results are quite different. For example, when my blood pressure monitor has a reading of 152/82 the device showed 102/66. My average BP for the last month of measurement was 142/79 whereas the device was 106/67, not even close. I think part of the problem is the calibration process, which rarely works first time. I exchanged email with support but they sent me a pdf of how to calibrate the device, which while grateful did not address the issue. Neither did they propose to exchange the device, which could be defective or the cuff provided. Having wrote the above and giving it a low score I hope I’m in the minority with this product as this is the future of BP measurement.
Very similar experience to ours. Difficult when the measurements appear to be inaccurate but also have no consistency in when measurements are taken. I’ve asked them to add the capability to export readings in CSV form; apparently others have asked for this, so perhaps it may come in future though sadly, I’ll be unlikely to benefit from it as I will have abandoned it before then.
Like a few suggestions already made. It would be good to have an option to do calibration manually by an external BP monitor. That way the device can accurately function when the Cuff details are clearly wrong. There may need to be some disclaimer about the results being based on the modified calibration is at the owner’s responsibility/risk – I can live with that! Also, need to have the days/months/years on a rolling basis, not straight calendar basis. When comparing results you want to look at the previous 7/30 days of data, not just the first day of the calendar week/month! Additionally, I would like to see a CSV export of all the raw data, not just the nice chart. It’s nice to know when an exception occurs but this is difficult when data is averaged over the day/week/month/year.
There has not been an upgrade of the app for over a month and this is greatly needed to keep in line with the competition in terms of reporting, export of data, etc. As mentioned the device has potential to be a great device but only if the bugs are fixed, including the Cuff override when it’s plainly incorrect.
My issue is that my BP can vary wildly over the period of a day – 80 points would not be untypical, and it tends to drop when I’m active, so without taking measurements at all times it’s likely to be not very useful.
I don’t think it’s supposed to take BP measurements when you are active. BP is taken at rest. When I tested it, most of my results were for the period when I was sleeping.
Check out Cardiex and their new cuff less blood pressure monitoring device….and great App to go with.
I can’t find any reference to obtaining the CardieX device, which appears t be in an early stage of development at present.
I have been using the Aktiia device for more than a month right now and I am quite satisfied. Initially the device could not take too many measurements a day but then I learnt that I could take more measurements by tightening the device. So now I can take a measurement every two hours when I am not very active. The only thing I noticed is that the measurements are linked to the calibration in the sense that if you calibrate the device in the morning when BP is higher, all readings will be consistently higher than readings obtained when calibration is performed in the evening when BP is lower. This means that even if the device will continue to monitor the excursion during the day, it will show a consistent bias related to the time of the day when the initial calibration was performed. Therefore I suspect that the best data are obtained if the device is calibrated during the afternoon when my BP readings are in the middle of the excursion. Anyway I am learning a lot from my device and how behaviors, diet, sleep can affect your BP. For instance I noticed that caffeine is lowering my average BP even if it increases the punctual value after drinking a coffee. Same thing happen with chocolate. So a moderate consumption of coffee and chocolate would be positive but should be avoided if you are suffering from isolated high BP peaks. Hope you will enjoy this device.
We have found that the wrist bracelet produces systolic measurements that are 20 points lower on average than a properly calibrated arm band. Diastolic is about 5 points lower. Recording BP is very sporadic and I have asked Aktiia support for more information on how long a person has to be at rest, and what the trigger for a measurement is. It would be helpful to understand how best to use it, how long to remain at rest and so on. They just shut down my email ticket after giving some unrelated replies that did not address the problems. So despite having great potential, it is in fact not useful for us. Oh, and I learned of the monthly fee after the first year only from this review. In case my wife – the user – had some issues that made the Aktiia unhelpful to her alone, I tried to calibrate it for me, but it simply could not do it and refused to calibrate. The £199.99 cost is about that for a private consultation, so as I like to test new technology, it is worth wasting the money. Just. But I couldn’t recommend it to anyone.
What monthly fee are you referring to? I bought my band for £199.99, do they want any more money?