The Omron HeartGuide (OHG) is a digital wristwatch that takes oscillometric measurements of blood pressure. Named to TIME Magazine’s Best Inventions of 2019 list, the promise of this device was succinctly summarized by an Omron executive: “Integrating a blood-pressure monitor into a sleek watch that also measures sleep and activity makes staying on top of cardiovascular health easy and provides a fuller picture of overall wellness.”
Previously on the skeptical cardiologist, I described my excitement at the HeartGuide’s ability to “serve as an accurate and unobtrusive daytime ambulatory blood pressure monitor.” After wearing the HeartGuide for a week and using it in a variety of situations to measure my blood pressure I had begun rethinking my usual recommendation against wrist blood pressure cuffs.
For me, the great attraction of the OHG was and still is the ability to measure your BP “anytime, anywhere.”
Despite my unabashed enthusiasm for the Heart Guide’s ability to provide facile daytime BP monitoring, certain limitations need to be recognized.
Herein is my more detailed, objective and pragmatic review of the device.
What Is In The Cube?
The OHG is available on the Omron website for $499 but upon checkout currently, Omron is providing a 10% discount along with free economy shipping.
The device is available in medium and large wrist sizes. I sized my wrist as a medium using the measuring tool on their website.
Proper wrist sizing is crucial for accurate BP measurement.
The OHG ships in a black cube.
Inside the cube you will discover:
- 1 Monitor
- 1 Paper Sizing Guide
- 1 Instruction Manual
- 1 Quick Start Guide
- 1 Charging Clip
- 1 AC Adapter
- 1 Charging Cable
- 2 Replacement Cuff Sleeves
The OHG is large but stylish in appearance. It weighs 115 grams and the watch dial has a diameter of 1.9 inches.
I found it took about 2 hours to fully charge the battery and that the device remained charged for about 48 hours.
Preparing For Blood Pressure Measurement
Your monitor has a built-in heart zone indicator that is used as an aid in determining if your monitor is at the correct height and position. It has been designed to work with most people so that when your wrist is at the correct position relative to your heart, your monitor will vibrate once. If it does not vibrate, your monitor may not be at the correct height and position relative to your heart.
Due to differences in individual size and physique, this feature may not be helpful in all cases and you may wish to turn off this feature. If you feel the position of the wrist, according to the heart zone indicator’s guidance, does NOT match your heart level, please turn off this feature and follow your judgment.
It’s not clear to me how the OHG knows that it is at heart level. I experimented with various positions including lying on my back and standing with my wrist definitely at heart level. Sometimes the OHG agreed, others not.
Measuring A Blood Pressure
Once positioned properly simply push the top button on the watch and put your wrist in the appropriate position. You will notice a vibration followed by an initial mild inflation of the cuff that lasts about 15 seconds followed by a pause of a few seconds then a full , tight inflation of the cuff.
The entire process takes over a minute and is significantly slower than the upper arm BP cuffs I have been using.
When completed, the cuff deflates and the systolic and diastolic blood pressure along with pulse rate are displayed.
Before I could recommend the OHG in particular or wrist BP cuff devices, in general, I needed to know how they compared to the gold standard brachial artery, upper arm BP cuff.
I asked Omron for data supporting the accuracy of the OHG and they provided me with a copy of a 2019 paper entitled “Validation of two watch‐type wearable blood pressure monitors according to the ANSI/AAMI/ISO81060‐2:2013 guidelines: Omron HEM‐6410T‐ZM and HEM‐6410T‐ZL”
The lead author of this study is an MD, PhD working at the Jichi School of Medicine in Japan and his 3 co-authors all work for Omron Healthcare, Kyoto, Japan, which provided funding for the research so this skeptical cardiologist takes this information with a grain of salt.
The introduction to this paper points out that ambulatory blood pressure monitoring is important to help identify individuals who have higher blood pressure outside the clinic. Such individuals have masked hypertension, the opposite of white-coat hypertension.
The researchers concluded that both the large and medium wrist HeartGuide devices were accurate and fulfilled criteria set by the American National Standards Institute, Inc/Association for the Advancement of Medical Instrumentation/International Organization for Standardization.
Here are the Bland-Altman plots from that study
Note that although the average difference between the reference BP and the HeartGuide systolic BP is close to zero there is a significant variation from zero for individual measurements with some 20 mm Hg higher and some 20 mm Hg lower.
My experience confirms this significant individual variation. I took a number of simultaneous measurements using the HeartGuide on one wrist and a brachial BP cuff on the contralateral arm. I did this over multiple days under differing circumstances and with the devices on different arms.
I found that the HeartGuide systolic blood pressure was on average 10 mm Hg lower than the brachial BP when my blood pressure was high (>140 mm Hg). When my systolic BP was between 120 and 130 mm Hg the HeartGuide was 5 mm Hg lower than the brachial and when my blood pressure was less than 120 mm Hg the Heart Guide and brachial BPs were identical.
I made similar measurements on other volunteers and found some had consistently identical wrist and brachial SBP whereas others had consistently higher blood pressures by wrist compared to brachial techniques.
Because of this individual variation I highly recommend users calibrate the OHG (or any wrist-based BP cuff) versus a standard BP cuff over a series of days with multiple measurements to see how the two measurements compare. If you find a consistent over or underestimate then the device can be used with this known adjustment.
Comfort, Form, Fit
The OHG is big. and it is bulky. The fastening strap is made of thick rubber and underneath that is the inflatable microcuff which works like the larger cuffs designed for brachial/upper arm measurement.
I was always aware of something on my wrist when I was wearing it. The OHG cannot be accessed if you are wearing a coat or any garment with thickish sleeves. Getting most upper garments on and off while wearing the OHG is a chore.
In the picture below you get a feel for how the OHG interacts with long sleeve garments. My shirt sleeve would not slip over it. When I was wearing a coat or sweatshirt I could not access or view the OHG as its large size prevented pulling back the sleeve.
Some Other Things the OHG Does
The OHG measures steps and it tells time. Omron also indicates it can be used to measure sleep quality. Frankly, I did not test this feature because I felt I would not be able to sleep comfortably with the device on my wrist.
The OHG pairs via Bluetooth with the Omron smartphone app “Heart Advisor.” The app displays imported BP, pulse, activity and sleep data in various graphic formats.
Data can be exported from the Heart Advisor app by email in either an Excel or PDF file. This feature would allow the user to conveniently send recorded BPs to their physician.
The OHG sends an alert when you receive a text message or phone call but you can’t see the text message or answer the call.
Overall Pros and Cons
I am still a fan of the OHG despite the limitations I have indicated above.
I don’t see most people using the OHG as their every day smartwatch The inconvenience and discomfort factors for most will outweigh the benefits.
However, I do see a very beneficial role in wearing the OHG periodically for targeted purposes. For example, it could be worn to work once per week to determine how one’s blood pressure is reacting to stressful situations or to the gym to assess one’s blood pressure before and after a workout. At least one study suggests that BP obtained at work is superior to 24 hour or sleep BP in predicting end-organ damage (manifested by echocardiographic left ventricular hypertrophy) from hypertension
If Omron can develop a method for the device to automatically trigger during sleep and provide accurate nocturnal BP measurements this would be a huge advance in the management of hypertension.
N.B.Technical Specifications for the OHG
Display: Transflective memory-in-pixel LCD
Memory: Blood pressure measurement up to 100 times, Activity measurement up to 7 days, Sleep measurement up to 7 times, Event up to 100 items
Transmission method: Bluetooth® low energy technology
Power source: 1 Lithium ion polymer rechargeable battery, AC adapter
Battery lifespan: Will last for approximately 500 cycles, 8 times/day measurements in normal temperatures of 77 °F (25 °C) when new battery fully charged
Battery life: A typical user can expect to charge HeartGuide approximately 2-3 times per week, depending upon the frequency of use of HeartGuide’s features
Weight: Approximately 4.1 oz (115 g)
Dimensions: Diameter approximately 1.89” (48 mm), Case thickness approximately 0.55” (14 mm), Band width approximately 1.18” (30 mm)
Measurable wrist circumference: Medium – 6.3” to 7.5” (160 to 190 mm), Large – 7.1” to 8.5” (180 to 215 mm)