PurePulse 2.0 news and reviews

[Mithras90]

Fitbits description about it:

24/7 Heart Rate Tracking with PurePulse 2.0

With an all-new multipath sensor, Sense delivers PurePulse 2.0—Fitbit’s 24/7 continuous heart rate tracking for exercise, sleep tracking and everything in between.

Here are some mentions in different reviews since the Sense launched regarding PurePulse 2.0, with key points underlined:

"The Sense boasts improved heart rate tracking with its PurePulse 2.0 technology, which uses a new multi-path heart rate sensor. Basically, that means it’s checking your heart rate in more ways and in more places, which, when combined, should provide a more accurate picture of what your heart is doing. This is something I would have liked to spend more time testing, but early results were promising. I would spike my heart rate doing some exercise and then would manually count my beats per minute using a stopwatch and compare it to the Sense. Not only did the Sense generally stay within a few BPM of my manual count, but it would usually get up to speed faster than the Garmin Fenix 6 Pro Solar, which seemed to have a bit more lag."

- The Verge

https://www.theverge.com/21450123/fitbit-sense-review

"Sense uses Fitbit's new PurePulse 2.0 heart rate monitor, which the company says has an improved algorithm to offer its "most advanced heart rate technology yet." However, I didn't have the best experience with it during my workouts. 

To test it out, I wore the Sense, Apple Watch Series 6 , and Polar H10 heart rate monitor, and compared my stats. Throughout three separate runs, I found my average heart rate on the Sense was always off by about 10 to 20 beats per minute (BPM). Now, contrast that with the measurements from my Apple Watch and Polar strap — both of which were only about one to two BPM off from one another.

Throughout my runs, I noticed the Sense struggled to keep up with change in pace in real-time. For example, when I was at a light jog, the BPM on the Sense matched the rest of the devices. But when I'd ramp up my speed and increase my heart-rate, it would take a while for it catch up with both the Apple Watch and the Polar H10.

I also tested it during a quick, 15-minute kickboxing session and ran into the same issue. But this time, the average BPM was off by about 20 BPM."

- Mashable

https://mashable.com/review/fitbit-sense-smartwatch-review/

"We took the Sense for a pretty intense spin session and noticed no unexpected dips in heart rate that indicate an issue with fitness trackers. Our heart rate shown on the watch face mirrored our efforts on the bike, with only a slight delay as you'd expect from any wrist-mounted heart rate monitor."

- Techradar

https://www.techradar.com/reviews/fitbit-sense

"My “biggest” problem with the Sense, however, was heart rate-tracking during exercise. This may be due to the new Pure Pulse 2.0 algorithm, but in general, my workouts had average bpm readings that were about 5 bpm lower than my Apple Watch SE and the Polar H10 chest strap. That’s not that serious of a change. However, I did notice that sometimes the Sense lagged by as much as 10-15 bpm compared to the Watch SE and Polar H10. This wasn’t uncommon in the early days of wearables testing, but I can’t remember the last time I saw two trackers that were more than 5 bpm apart in real time.

This lag didn’t occur all the time, or even in every type of exercise. I only encountered it while running outdoors. Upon reviewing my heart rate data after my runs, however, the graphs from the Fitbit Sense, Apple Watch SE, and Polar H10 corresponded with each other. That leads me to believe Fitbit’s exercise app might struggle to keep up with real-time data for certain exercises. For instance, I didn’t have this problem with strength training, walks, or yoga sessions. This isn’t going to be a problem for everyone, but if you are someone who trains according to heart rate zone, it’s not ideal. I’ve asked Fitbit whether this might be an exercise app issue, but have not yet received a response. Regardless of whether it’s an algorithm or app issue, it’s more of an inconvenience than a sign the Sense is irredeemably inaccurate."

- Gizmodo

https://gizmodo.com/the-fitbit-sense-is-one-hell-of-an-ambitious-smartwatch-1845097433

"First example, this relatively easy paced run , compared to the Garmin HRM-PRO chest strap and Apple Watch SE, both of which were fairly similar, except the Fitbit Sense was often 20+ bpm high..... // .. You can see how for the first 10-12 minutes it’s all over the map – in some cases by 20BPM. It’s nuts.... // ... having a third device to compare against (more soon), I can say without question the Fitbit is wrong here./// .... Or we can go with one of my other faster paced workouts, with a few intervals tossed in. And the Fitbit Sense was wrong almost the entire time, by at a minimum 10bpm (which, is a lot). And sometimes 15-20bpm. It’s the yellow line at the bottom. /// ...In fact, the only thing that performed worse than it was the Whoop 3.0 strap, because…well, Whoop. In fact, during a few runs, I started wondering if Fitbit had licensed the tech from Whoop, since it was often equally as bad and often failed in semi-similar ways. The yellow line of the Fitbit Sense, and the blue line below are similar during these intervals. Low, slow, and inaccurate. // .... Look, it’s bad. And even when it somewhat appears close above – that’s only because you’re skewing your expectations by the parts it’s 10-20bpm off. Being 3-5BPM off looks ‘normal’ by comparison, but that’s still wrong. And bad."

- DCRainmaker

https://www.dcrainmaker.com/2020/09/fitbit-sense-in-depth-review-all-the-data-without-the-clarity.ht...

Conclusion:

It seems to me like the PurePulse 2.0 really won't be much better than the old one, and won't be enough for those/us who do intense gym workouts and HIIT. While it is a mixed result, some of these reviews point out the same issue that is found in the Versa 2, which is that it rarely keeps up with the BPM during intense workouts. This means that I will continue to have to bring my Polar H10 to the gym.

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My History:

I bought the Versa 2 on release day and was extremely hyped about it. Quickly I realized it's flaws however ,especially considering the HR monitor. It just wouldn't measure my HR correctly during workouts.

Several indepedent tests had the same result as me;

The HR monitor on the Versa2 worked fine while doing nothing, but as soon as I hit the gym it totally missed everything. Weird part is; it got it mostly correct whenever I was running. No matter if I was outisde running or on the mill, it was pretty accurate with a variation of 2-3 BPM from my H10. But as soon as I did a gym workout session, it completely missed.

Compared to the Polar H10, which is highly accurate, the results during one month of gym workout 6 days a week was:

- missed average HR of 15-20 BPM

- missed peak HR of 15--20 BPM

- missed burned calories with 200-300

Where the Versa 2 showed lower numbers than the H10.

I've discussed thjs issue in the forums and had several other avid gym-goers with other types of accurate HR monitors try it out, and they all had the same results. Obviously I scoured the forums and talked to customer service about this issue and did everything they recommended as well as everything they didn't; having the watch sitting lower down not so tight, having it higher up real tight, switching arms, all kinds of different distances and tightness levels etc. I even tried shaving where the watch sits to ensure maximum readibility.

[IvieV]

Hi.  Has anyone have any experience or would recommend Garmin vivoactive 4S?  I have had a versa2 for the past 2 years and it was working okay for my needs until I noticed heart rate inaccuracies. I could be doing an HIIT workout/cardio and HR would read 100, I would remove and readjust and leap to 150s or more; if this is not accurate my burned calories/caloric intake are off as well.  I spend way too much readjusting my Fitbit and I'm still halfway through my annual membership. I was a whole lot more disappointed when my gym added 3 rowing machines and Fitbit doesn't have a way to track this type of workout. I have been considering switching to a Garmin vivoactive 4s since I would be able to track rowing machines and still be able to track strength training/lifting weights/yoga/body weight workouts, etc.  I did grow fond of the sleep tracking portion on Fitbit but I rather keep accurate HR and calories in/out (I do use Myfitnesspal to track macros & micros).  Any suggestions?

[Yme]

Hey! 😁

First off, wrist based trackers, especially Fitbits, do not give good caloric estimates. Don't use them for that. It's simply not possible for them to do it because your body has dynamically changing energy needs. It adapts to what you do, and changes how much energy it needs depending on that. (Good article here. It's a bit long, but it goes through what science says about these trackers https://www.google.com/amp/s/www.strongerbyscience.com/research-spotlight-wearables/amp/ )

Also, let's say we are making a tracker, and we pull in 10 people to check how much calories they burn. Let's say, for simplicity, that person one 100 calories per day, person two burns 200, person three bursn 300 and so on up to person ten who burns 1000. All of them doning the same activities.

To make our device we then make an average of all these people, and create our algorithm. The average of all of these would be 550.... The final result is that allmosy none of the people would get any useful expenditure data from the device. It would only work for persen 5 and 6... And this is one of the many reasons why you can't trust wrist based trackers for estimating your energy needs. You might be lucky number 5 or 6, but most likely you aren't.

The only way for a general consumer to get an accurate number on energy expenditure is to use one of the apps that calculate it for you based on you logging all calories you eat and your weight change every day. They take about 30 days to give you a good number. MacroFactor is a good one.

There are several things you can use trackers for though, like sleep tracking (Fitbit and Whoop are the only ones that doit well, and they're about 60% accurate at predicting sleep stages), menstrual cycle tracking, training logs, activity motivation etc. 

Between Garmin and Fitbit, I like Garmin the best. It's HR tracker is much better than Fitbits. It has good sleep tracking with a lot of features, but the sleep stage tracking can be really bad. You also get much more data in everything you do, and there's no "pay for premium features".

So as a sports tracker, Garmin's are better, but as sleep stage tracker, Fitbits are the best. Fitbit also has a lot of cool community features if you like to use them.

Oh, and Garmin watches let you use a chest strap as well, for perfect HR tracking. Straps measure your heart directly, rather than estimating through a light sensor on your wrist, which is good if you want to do heart rate zone training or strength training. Wrist based trackers are horrible at tracking HR during strength training)

Edit: If your interested in how energy expenditure actually works, here's a great article for you.

https://www.strongerbyscience.com/research-spotlight-energy-compensation/

[Mithras90]

Hi @IvieV ; I have no experience with the vivoactive 4S, so I might be irrelevant, but:

Another option would be to do what I still do today; Use a chest-strap (I use Polar H10) for when you want the extremely accurate results, and the Fitbit for the rest (sleep tracking, rest pulse, etc). I found that this is the cheapest option, as chest straps aren't as expensive as the watches (Vivoactive 300 eur vs H10 75 eur). This way you can still use your Fitibt as well and not let it go to waste. I actually still let the Fitbit track the amount of training sessions I've had per week.

As for trying to accurately measuring burned calories; I gave up on that a long time ago. The way I do it now is that I use the burned calories per training session from my H10, subtract 20%, and then add that to my basal rate of 1500 kcal/day.

So 1500 kcal + 0.8*burned calories from each training session.

This has allowed me to actually lose the fat I wanted while maintaining muscle mass.

Hope you'll find a solution that fits you!

[Stev12]

I just read a online review from TechAdvisor making the claim that the new Charge 5 is using the new PurePulse 2.0 version. I posted the link below. Yet everywhere else is writing that the Charge 5 still runs the older original PurePulse first version. Does anybody know the truth? Is Charge 5 really equipped with PurePulse 2.0???

https://www.google.com/amp/s/www.techadvisor.com/article/724350/the-best-fitbit-2022-which-fitbit-is...

[Guy_]

Hi @Stev12 - the Charge 5 does not use the new PurePulse 2.0 version. See https://community.fitbit.com/t5/Charge-5/Frequenza-cardiaca-pure-pulse-2-0-Charge-5/td-p/4980709

Which states that "I would like to confirm to you that the Charge 5 uses standard PurePulse technology and not PurePulse 2.0 (as found in the Sense or the Versa 3). "

[Stev12]

The Versa 3, Sense and Charge 5 use the updated and more accurate PurePulse 2.0 Sensor. 

[Guy_]

@Stev12 - as you posted the article previously it would still seem that it is not correct.