Sense heart rate and calories differ from Versa

[SunsetRunner]

I recently got a Fitbit Sense to replace my aging Fitbit Versa 1.  It seemed the Heart Rate and calorie Burn for Exercises are Drastically different.  To test I setup the Versa 1 on a separate account and have been wearing it on my right Hand while Wearing Sense on my Left.  The Below graphs are for the exact Same Exercise,  Any thoughts on why so Different?

Versa 1 Results:

Sense Results:

Moderator Edit: Clarified subject and updated label

[JohnnyRow]

Calorie burn is not a separate issue from heart rate.  Calorie burn comes from heart rate.  So if the heart rate is so different, many things stem from that.

[Giampi71]

As @JohnnyRow says the problem comes from the HR measurement. Specifically Versa 3 / Sense offer HR sensor performances that are poor, particularly evident at high HR.

As the problem exists since the release of the smartwatch I'm not sure it will be ever corrected, even the last update changelog does not address anything concerning HR.

[MichaelLyons227]

Ok.  But why is the Heartrate so different between left and Right Hands.  Same Exercise, Same Person, So should be same HeartRete.

[Clove6060]

It is possible to have a significant difference in the pressure recorded in the right and left arms but that would be a signal for circulatory problems.  Some doctors check pulse in both arms. 

[LZeeW]

@SunsetRunner   If you look at the backside of both devices, you will see a different arrangement of the LED emitters and sensors.  Users with other models like the Ionic and Charge 4 will see a different arrangement.  Both the hardware and software algorithms are different among the devices.  If you added an Ionic, a Charge 2, and a Charge 4 to your experiment, you would probably get three additional different heart rate traces.

I am confident this is why we see so many user posts about heart rate accuracy.

[IgorR11]

It would be best to make a comparison on different systems. For example, using an apple watch, garmin or galaxy watch, then see which metrics compare to see if there is a very high divergence from the sense

[Murray67]

I have the exact same problem, though I haven't worn both watches at once to compare them. The original Versa's HR accuracy (which isn't great) is just miles better than the Sense's.

The Sense HR sensor hardly picks up elevated heart rates at all. I can do a heavy set of deadlifts, feel my heart racing and check the Sense: 109 bpm. 5x10 of 60% RM squats: 110 bpm. I haven't ridden my bike yet with the Sense, but I assume it'll be a similar disaster.

I've been using Fitbits for several years now, so I'm very familiar with the quirks of wrist-mounted HRMs, especially for weightlifting, but this is another level entirely. How is it that they labored so long on the PurePulse 2.0 sensor only to end up with this debacle?

Yes, I've moved it further up my arm (where it keeps slipping down), I've experimented with the tightness of the strap. No difference. The most irritating thing is that my Active Zone Minutes have dropped to near zero, where the Versa usually reported I'd fulfilled my 150 minutes on the second day of the week.

I mean, this is fundamental. The HRM is basically the reason people buy fitness trackers in the first place, and many of the app's features are based on that functionality. Fixing this should be the top priority for their flagship watch.

[MichaelLyons227]

I got to looking into this and doing an experiment when a Friend noticed a big Drop in the Stats for Her Versa 2.  Seemed to be tied to a Firmware update.  It seemed like it was more accurate or she was getting better numbers before.  She has been conducting the same sort of experiment with Versa 2 and Charge 3.  Charge 3 is always picking up the higher Heart Rate shows more Peak and Cardio.  For her the Charge 3 results were closer to what she used to see on her Versa 2.  She was considering buying a new one as thought hers was Broken.  It sounds like she would have been disappointed if she made that purchase.

It does seem the More Cardio intense are closer - Spin this morning for me was 7 Calories different between the 2.  I tightened the Senses Strap as yesterday doing spin the different was close to 100 Calories.  It also seems for other Cardio intensive workouts it is at least closer. 

I have bee using the FitBit Tracers with my First bing Fitbit Charge, Then Charge HR (They had to replace one of this because heart rate monitor Quit), Then Blaze (It Stopped dead one day), Then Versa, I just picked up the Sense as the Original one was over 3 years old.  Thought the Ekg and the sensors might be useful.

Hopefully they can release s Firmware update that Fixes it.

[Giampi71]

Hello @IgorR11 

I think this is one the best tests available

[IgorR11]

From what I saw in the test there is a lot of divergence in graphics, it will be a software or hardware problem. I've used Apple Watch and Galaxy Watch devices together in sequence, each one's graphics were very satisfactory and with a low margin of error in cardio and weight training exercises

[thatssoketo]

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@MichaelLyons227 wrote:

Ok.  But why is the Heartrate so different between left and Right Hands.  Same Exercise, Same Person, So should be same HeartRete.

---

It's not the issue of right vs left hand. 

The Fitbit sense HR tracking is very poor, it's been noted on this forum many times. It's one of the most common complaints. 

[IgorR11]

In my country there is no support or sale for fitbit product, I bought a verse from a friend who went to the US and I really liked the watch, I made a point of buying a sense and the experience was not pleasant in the first month, it cost me $300.00 in my local currency is very expensive this value, the screen broke with only 4 weeks of use, I It hasn't arrived yet since my country doesn't have a fitbit store. I sent it from the USA to my country, but unfortunately I see a lot of divergence in the data obtained with the device, I really don't know if I believe the reports, I'm almost leaving aside and using my Apple Watch series 6 again. It's a shame, because I thought it would be an innovative product with all the sensors added in the sense, I hope there's an update that corrects this divergence in the HR

[Murray67]

An update. Since yesterday's comment, I have done the following exercises:

• My standard 2 mile lunchtime walk. With my old Versa, 115-120 BPM average, 10-15 zone minutes.  With my Sense, 102 BPM average, 0 zone minutes.
• 2.4-mile morning walk, half uphill with a 240 ft elevation gain. Versa: about 115-120 BPM average, 40-50 zone minutes. With the Sense, 102 BPM average, 0 zone minutes.
• 8.3-mile vigorous bike commute, long uphill section with a 440 ft elevation gain. Versa: usually around 135 BPM average, 50+ zone minutes. With the Sense, 128 BPM average, 33 zone minutes.

So the cycling isn't quite as bad as walking or weightlifting, but it's still pretty bad. Here's a comparison:

Versa vs Sense:

This is the same route, despite the slightly different GPS elevation profile, ridden at a very similar level of effort.

At this point, I'm considering returning the Sense, going back to the two year-old Versa (failing touchscreen and all), and looking for my first non-Fitbit tracker, since it appears that Fitbit has either no interest in resolving this issue, or no competency to do so. To so badly screw up the core feature of its products, the single thing that underlies most of its other features, is just staggering.  

[Micsb]

Are you certain your Versa2 is correct? My walking is on average 99-102. Compared with my chest strap this is right.

You sound to be in good shape and will have do forced walking or light jogging to start getting active minutes. My threahold is 112 and i cant get my HR above only by walking.

[Murray67]

It's a Versa, not a Versa 2, but I think the HRM is the same, so it's probably a distinction without a difference.

I checked the Versa against a chest strap during weightlifting, and as expected it cut off the peaks pretty consistently, while tracking the lower intensity periods pretty well. The chest strap showed >160 BPM during (say) heavy squats, while the Versa rarely got above 150. But my average weightlifting HR with the Versa was ~120 BPM, while with the Sense it's around 105.

Weightlifting comparison, Versa vs Sense:

Note the difference in scales: 70-160 on the Versa, 70-130 on the Sense. I'm pretty familiar with what 150 BPM (or whatever) feels like, so I'm confident the Versa was much closer

To make matters worse, those two records are from the same workout in my 531 program, about 3 weeks apart: 5/3/1+ deadlift at 75/85/95% 1RM, 5x 10 squat at 60% 1RM, 5x10 hanging leg raises. The Sense didn't pick up the deadlifts at all, reading my HR at around 100 BPM, gave me 5 small peaks for the squats, and 5 smaller peaks for the hanging leg raise. The Versa, by comparison, did much better on all lifts.

[Micsb]

I agree, the Sense is worse than terrible on weight lifting exercises.

Just did a quick test on three sets of pushups, took on the HR strap on third set where my system should have been warmed up well.

on the third set my HR rose up to 135 whereas it dropped to 90 on Sense. It started at 100 when i went down for the third set. Sense didnt go back up to 100 before the HR strap had droppe my HR back to 100.

Sense works well on cardio while i am running. It fails walking in rough terrain where the HR drops when climbing hills. It used to work alright on previous firmware, it got worse on the newest firmware.

[Murray67]

Thanks, sounds much the same as my experience.

It's well understood that wrist HRMs have difficulty with weightlifting exercises, due to the muscle tension in the forearm interfering with the optical signal. But my Charge 2 and Versa mostly just cut off the peaks for heavy lifts, while doing fine on lower-intensity exercises. The Sense is just another level altogether, like they reached all the way back to 2010 for their next-generation HRM technology.

Researching alternatives now, so if they don't come up with a firmware fix in the next few days... 

[Micsb]

I agree, already have my eyes on a Polar watch 😊 I am in no hurry and will probably wait for the Sense to break before switching. It fullfills my need as a motivational tool, however the latest firmware and HR really bothers me and will cancel my premium subscription to start.

Just went for a walk with my chest strap and found it close to impossible getting Sense above 105. Pushing myself hard i can get my Hr up to about 110-114, and Sense stops at 105 most of the time

[Micsb]

FITBIT what did you do to my watch tonight?

Elevation today is pretty accurate. Running same route as earlier, on a windy day, resulted in a height profile matching the route well. A short moning walk on a fairly flat route, it only credited me a few floors whereas it earlier applied up to 18 floors happily.

HR readings now much more responsive to changes in resistance. Three sets of pushups and it gladly followed the chest strap up to 130, albeit with a slight delay as is normal for optical sensors. Instead of dropping down as it did on two tests yesterday. Even on hills, it didnt stop at 105 and followed the HR up closely matching the chest strap.

And thats not even all, you also added access to historic data in the Health Metric that i Have been wanting for a long time. I can now compare my numbers today with last autumn. Had a long period for 4 months, stressed out, inactive and gained a lot of weight. Been working getting back into shape and can now copare my current progress with my status last time I was equally active.