Can the Galaxy S9 measure your blood pressure? We put its new optical sensor to the test...

Can the Galaxy S9 measure your blood pressure? We put its new optical sensor to the test...
Samsung has big plans for its pulse meters, and the new one on the Galaxy S9 and S9+ "provides richer, more accurate information on users’ health status." How does it do that? Well, there is a new, more accurate optical sensor on the back of the S9 and S9+, for once, which can measure something called the Heart Load Factor, which is a gauge of the real-time demand that is tasked to your heart. Of course, it comes with the usual "intended for general wellness and fitness purposes only" disclaimer, but that's usually all everyone is using those for anyway.

The funkier part is that the new heart rate sensor kits on the Galaxy S9 and S9+ are able to take your blood pressure. Yes, you read that right, no arm cuffs, no wrist monitors, just you and your trusted Galaxy S9 after 11 sausages in a row. We kid, but Samsung entered a partnership with the University of California, San Francisco (UCSF) to leverage the "revolutionary optical sensor" on its new flagships by engaging into a pilot study in digital health. 

The way the optical sensor works, is the way some apps in the Play Store read your BP with the camera and illumination by the LED flash, yet is way more precise than those. We'll spare you talks about Ballistocardiography and Photoplethysmograph readings, but will just say that the optical sensor collects info from your fingertip pulse between heart beats, and runs them through linear regression analysis, set by a baseline reading with a medical-grade arm cuff BP monitor.

UCSF has created an app called My BP Lab, which aims to follow the study participants' blood pressure and stress levels throughout the day in the span of a few weeks, using the data for both number crunching, and improving the accuracy of the optical pulse reader on the S9, so that it becomes a viable tool for following your BP. Well, UCSF just released the My BP Lab application, as promised, for the official launch of the S9, and we immediately took it for a spin to measure how precise will the blood pressure measuring abilities of the phone will turn out to be against a regular arm cuff monitor.

Download My BP Lab blood pressure study app for Galaxy S9


To a great extent correct, it turned out, but don't throw out your arm or wrist cuffs just yet. Once you create a study participant account in the app, enter your details, and set a baseline measurement with an orthodox arm cuff, then the phone takes over, and we barely noticed a maximum of +/- 5 point difference between the cuff and the handset's readings afterwards, as long as our volunteers were sitting still.

With activity, however, the measures were profoundly different. When you exercise, your systolic (the upper reading) measurements can skyrocket, and that is where we logged huge discrepancies between the cuff, and the optical reader measurements on the same baseline. 

Both arm cuff monitor makers, and the app creators, advise to log your BP in a calm state and sitting, rather than running around with a cuff on your arm, yet it's something to keep in mind if you use the phone to measure the change in your BP reading after rigorous activity or in stressful situations. We also measured the same +/-5 points discrepancy when we logged our BP with another person's baseline, and then controlled it against our cuff measurements, too.

*deviations between the cuff and the Galaxy S9 were much larger after physical activity than the ones logged here in a still state

Long story short, you shouldn't rely entirely on your Galaxy S9 or S9+ to log any daily BP readings required by your doctor, but for a more relaxed blood pressure tracking, or in emergencies when you don't have the cuff around, the results turned out to be viable, mainly for observing trends and change amplitude. 

Medical revolution? On the cuff cusp of it just yet, though one of the purposes of the UCSF study is to perfect the algorithms behind the optical reader measurements, so if you want to help science make BP readings on your phone an accurate tool, check out the My BP Lab app from the download link above, and take one for science with your Galaxy S9 or S9+.

Related phones

Galaxy S9
  • Display 5.8" 1440 x 2960 pixels
  • Camera 12 MP / 8 MP front
  • Processor Qualcomm Snapdragon 845, Octa-core, 2800 MHz
  • Storage 256 GB + microSDXC
  • Battery 3000 mAh(31h talk time)
Galaxy S9+
  • Display 6.2" 1440 x 2960 pixels
  • Camera 12 MP / 8 MP front
  • Processor Qualcomm Snapdragon 845, Octa-core, 2800 MHz
  • Storage 256 GB + microSDXC
  • Battery 3500 mAh(35h talk time)

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27 Comments

1. darkkjedii

Posts: 30899; Member since: Feb 05, 2011

This just became the most awesome phone ever! As a health nut, these are the actual features and specs I crave. The hell with camera clarity, give me health features galore. I believe in being in tip top shape, and heart health is a major priority for the jedster. Kudos Samsung...major kudos.

12. bucknassty

Posts: 1318; Member since: Mar 24, 2017

i wish reviewers would mention this more often... samsung just kills the hardware

15. darkkjedii

Posts: 30899; Member since: Feb 05, 2011

Yes they do.

32. JonGarrett

Posts: 34; Member since: Aug 06, 2011

They won't out of jealousy. Sadly, most "tech boogers" are Apple fanboys and they really really hate giving Samsung credit for anything.

18. SayMobile

Posts: 156; Member since: Jan 29, 2014

Well said. Though its camera is also the highest rated for a smartphone.

20. darkkjedii

Posts: 30899; Member since: Feb 05, 2011

They kill it with cameras too, both quality, and features.

22. Xperia14

Posts: 1206; Member since: Sep 01, 2015

Yes this is great! Hypertension (systolic blood pressure higjer than 140 mmHg and/or diastolic higher than 90 mmHg) is a big risk factor of cardiovascular diseases. It has a high prevalence, but yet most people don't know their (average) blood pressure, as they have never measured it. Almost everyone has a smartphone, so if this becomes widespread, people who didn't know that they have hypertension will know, and they can get medication as it is treatable! This can potentially bring down mortality.

25. darkkjedii

Posts: 30899; Member since: Feb 05, 2011

Yes sirrr

2. PhoneCritic

Posts: 1345; Member since: Oct 05, 2011

Nice feature

3. TechSceptic

Posts: 1156; Member since: Feb 05, 2018

It's actually pretty damn accurate for a phone. That's an awesome feature to have, ontop of the already impressive health features of the Galaxy phones, such as oxygen levels and heart rate. I personally A/B tested the oxygen level feature, and it was within 1% of the proffesional medical equipment in the hospital. It's really impressive how many health features there are in the Samsung Galaxy phones and how well they work. I can't think of a single other phone that offers as good and as many health features. I don't think there is anything close.

13. bucknassty

Posts: 1318; Member since: Mar 24, 2017

Samsung puts so much in to their phones, its nice to have the essentials... but to have more... thats a plus

4. cmdacos

Posts: 3969; Member since: Nov 01, 2016

Pretty impressive for a static sensor. Nice work.

5. sissy246

Posts: 7035; Member since: Mar 04, 2015

The s9/+ are awesome phones and now I can't wait to see what the note 9 will be.

7. TechSceptic

Posts: 1156; Member since: Feb 05, 2018

I'm really hyped for the S10, their anniversary phone. The note 9 is going to be good, but i think they're saving all the fantastic stuff for their anniversary phone. I love the direction Samsung has been heading ever since the S6.

6. afrohoxha

Posts: 232; Member since: Mar 13, 2014

It's pointless to measure pressure during activity. Different parts of body are affected by the level of activity performed in them because movement interferes with the oscilloscope of the metering device. Anyway those stats sound really good

8. majerb

Posts: 1; Member since: Mar 16, 2018

is the s9 the more accurate measurement? it will be interesting what this study finds

10. ph00ny

Posts: 2014; Member since: May 26, 2011

It looks like the figures are all within the range. Even on cuffs, consecutive measurements won't give you the same reading

9. jjface

Posts: 224; Member since: Jun 07, 2017

Nifty feature.

11. Cat97

Posts: 1804; Member since: Mar 02, 2017

This is the only reason why I want an S9, despite its other shortcomings. It's a great feature. Think that you can take your blood pressure during workouts or when stressed...very useful indeed.

14. blueyzfr6

Posts: 28; Member since: Nov 02, 2015

I wonder if I can use my HSA card and buy the S9+ and write it off as a Blood Pressure Monitor....

16. LikeMyself

Posts: 631; Member since: Sep 23, 2013

I hope this becomes more accurate with time as it'd help us greatly!

24. xekrubx

Posts: 1; Member since: Mar 16, 2018

Received my S9+ on Wednesday. I only learned about this feature and the My BP app yesterday. (when the app was released) Ive so far only been able to "check in" three times after much finger adjustment. This current evening "check in" just isnt working. Ive tried everything the app suggests. While its cool to see this tech in a phone, its been a giant pain in the rump to get working. Im not sure if its the app or the sensor but its looking like completing this 3 week reading trial is going to be next to impossible. I also cant seem to find actual BP numbers in this app. Just a +/- % reading Other than that, this is an amazing phone. Traded in my S8+ with zero regrets.

27. smajilya

Posts: 25; Member since: Aug 08, 2017

How about Blood Sugar measurement?

28. worldpeace

Posts: 3106; Member since: Apr 15, 2016

You'll need needle for that.. But probably we'll see affordable costumer-grade needle-less glucose meter in the next 1-2 years, and probably it will need another 3-4 years to make it small enough to put it inside smartphone or smartwatch.

29. aBoss

Posts: 164; Member since: Sep 15, 2014

awesome, cant wait for the Note 9. I am debating on Note 9 or XZ Premium This feature will be noted for sure :)

30. CreeDiddy

Posts: 2134; Member since: Nov 04, 2011

Well Apple Watch has been doing this for us since launch. Nothing special

31. GeekOFW

Posts: 59; Member since: Dec 14, 2016

One day, a Samsung phone will also be able to do Sperm Count. Kudos to Samsung for these health features!

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