Your smartwatch is lying to you

Many leading brands of smartwatch are outright lying to users about resting heart rate, providing us with misleading numbers that make us seem far fitter than we actually are. So I decided to get to the bottom of these resting heart fakes, with a bit of help from YouTube’s Dr @MedlifeCrisis.

*Chapters*

00:00 Introduction
01:59 Dropping some beats
03:17 Am I crazy-super-fit?!
04:18 Why lie?
06:47 Sleeping heart rate

*Sources and further reading*

Links at which various manufacturers state how their ‘resting’ heart rate values are calculated:

*And finally…*

[JamesSmith-qshx]

That moustache has it's own resting heart rate.

[MedlifeCrisis]

Amazing breakdown of all the data points, you've displayed them all fantastically. I've gotta say, I really do think the the 'cynical' reason you started with is the real reason. But yes, I accept the alternative that it's just simpler to measure overnight, however unlike the cardiac monitors we tend to use for patients, wearable devices have a major extra feature – accelerometers. Surely it would be really easy to find a 5 minute period with minimal activity and then use that for RHR. And maybe repeat several times.

I think sleeping HR is a perfectly good metric to track (as you suggest), but people should be made aware of the difference. We've been focusing on the low end, but I would hate people ignoring 90bpm overnight because they think it's in the normal range of 60-100. If someone's HR is that high at night, I'd recommend getting checked for things like sleep apnoea etc.

[markjohnson]

You can find more clarification on Apple's RHR figure in their 'Health' app. Specifically, it says "Your resting heart rate is the average heart beats per minute measured when you've been inactive or relaxed for serval minutes." and continues with "Resting heart rate does not include your heart rate while you're asleep and is validated for users over the age of 18 years."

[ayaderg]

while not backed by any data, my theory as to why the clinical world has settled on 60-100 instead of 50-90 as their RHR range, is because of the lack of time in a clinic setting. they take your heart rate & blood pressure after having gotten up, spoken with the nurses, maybe gotten nervous, walked around, etc. they don't have time to let you sit for 10 minutes in a stress-free environment just to get your heart rate.

[benpptung]

I've been wearing a Fitbit for over 3 years, and I believe that the Fitbit resting heart rate (RHR) feature is useful for two reasons. 1). Monitoring your RHR over the past year can indicate whether your health is improving or deteriorating. For instance, I quit consuming caffeine six months ago and noticed my RHR gradually decreasing. When I contracted COVID-19 three months ago, my RHR skyrocketed during the 10-day period, even while I was asleep. As my RHR began to decline, I started recovering from COVID-19. 2). I also check the lowest heart rate during my sleep, as I find it helpful in assessing my overall well-being. I've noticed that my lowest heart rate decreases as my body becomes healthier. In my opinion, the exact RHR number doesn't matter; what's important is observing the trend, whether it's going up or down, as it provides valuable insight into your health.

[peteracain]

As a cardiologist I can tell you *all peripherals* (including BP monitors) under-count the true *heart rate* (i.e. the number of times the heart contracts). This is different to the *pulse rate* How can this be true? Well even fit people get ectopic beats (VPC, PVCs etc) which cause a cardiac contraction, but not a strong enough pulse wave to register peripherally. I'm sure each device has a different threshold for detecting weaker pulse waves. Furthermore, these devices use temporal smoothing - some up to 10 beats at a time. That is why you don't see an instantaneous jump from 60bpm to 100bpm like you would on an ECG. The number is smoothed over time and can result in varying heart rates at any given time.

[NilsdeRooij]

Great clear video man! Conclusion; Don’t trust the number, trust the trend… Going up or down indicates more than the actual number. Same for body fat % on scales if you’d ask me :)

[bullman]

It’s quite hard to believe that there aren’t many YTers doing reviews like these! Everyone makes unboxing videos and reviews smart watches with a general focus on the products promises but no one actually stress tests the features itself.
So thank you for making this video!

[topaz_climber]

The thing is, a traditional ‘taken by a doctor in an uncomfortable clinic chair’ HR is way less likely to be accurate - no-one is relaxing in that environment. So it might be more true to say “traditional medical science is lying to you about what a healthy HR is”. And it’s easy to verify smartwatch measurements. I’ve done this many times to verify that my ‘slobbed out of the sofa in the evening’ HR of 38 or something is accurate. It is. Just now I’ve just sat on the sofa and confirmed my watch’s reading of 43bpm. Which is actually 2 beats lower that it’s been showing me as my RHR this week and 2 beats higher than my overnight sleeping low.

So I’d say the watch is doing a good job, and it’s the doctors who need to catch up!

[idontwantahandlethough]

Whenever I go to the Doctor's office, my heart rate is like 20-30 BPM over what it is normally. I don't want to tell them that it's because all the nurses that work there are ridiculously attractive and I'm trying very hard not to say anything too stupid

[fatboydim.]

As a Garmin user I know that my resting heart rate is roughly 45 BPM and when I have went into the NHS for a check up they always correlate that my resting heart rate is in the 40's and they ask me if I am an athelete, which I do fitness train, so its not any other underlying cause. I was always told that Garmin has a 10% error factor built in.

[tsmwebb]

My feeling is that the conventional definition is lower quality. 5 minutes of rest just in from a long run probably settles at a significantly higher number than after a short burst of exercise or a previously rested state, etc. Overnight conditions might tend to be more consistent. Maybe?

[johnmcgimpsey]

I wonder how reproducible each platform is. If I'm working toward getting more fit, I could be persuaded that it doesn't really matter if my indicated RHR is 58 or 48, as long as the trend is headed downward.

[mikewhite]

My AW telled me 2 weeks after I stopped smoking, that my average resting heartrate was going down from 80bpm to 60bpm, since the day I stopped smoking. That was a really cool surprise. :)

[supercurioTube]

That was a great video! I subscribed.
As Fitbit user for years, I found their RHR an actionable insight linked to general fitness, stress, recovery and stress.
And this insight really makes sense comparing to your own values, not someone else's.

Then once adding HRV it's even better as the later is really representative of recovery after exercise, getting sick and stress.

[noobiedooby]

Resting heart and hear rate is a tough number to measure health in my mind. For someone who's numbers are in the 60s while sitting but if i try to monitor it by myself it rises in the 90s. We things called emotions (anxiety) that can alter numbers. So sleeping heart rate seems like a better metric to me.. Mine is like 48-53 while sleeping.

[snithereens]

In the Apple health app, German version, I am told, that resting heart rate is validated for persons over 18 years old and is specifically not monitored during sleeping time. So, which is it?

[Kruperfone]

My apple watch was warning me about low heart rate while I'm asleep. I was pretty concerned and consult with my doctor, did some measurements, wore a cardiologist device measuring me for 3 days while logging everything what happens to me. Everything was fine.
Later it showed around 40 beats during the day, while I was actively talking and obviously didn't have that low numbers.

I'm happy for people who got important warning in time, but for me it gave only anxiety 😢

[Halbmond]

The video is already a year old, but I know for a fact that in the past, the Apple Watch didn’t (correctly) distinguish between sleeping heart rate and daytime resting heart rate before the sleep mode launched. I used to use a third-party sleep tracking app, and once I started using that, my resting heart rate dropped significantly. When the sleep mode launched, the resting heart rate went back up to a more realistic value again.

[KDEDflyr]

Garmin uses RHR as the lowest 20 minute average during sleep. They do specifically call out RHR as SHR. The reason you use SHR instead of RHR is that RHR is more affected by temperature, caffeine, stress, activity, etc. But you can isolate those variables during sleep so that you can compare apples to apples and monitor recovery. RHR isn’t very useful for performance monitoring compared to SHR. I use Garmin’s health snapshot in the mornings after waking up to get an accurate RHR with HRV. My RHR sitting on the couch is 49. Sleeping varies from 44 to 50 depending on how hard my training load has been.