Blaze vs Chest Strap (polar H7): A review

[AdamMSC]

PLEASE READ THE REVIEW AT THE BOTTOM: I got different results my second time around, but I am leaving this up here as a source of information for others.

Testing

I tested the Blaze vs the H7 today at the gym. I used Endomondo for the H7 and the Fitbit app (of course) for the Blaze. I started the exercises simultaneously and used aerobic and anaerobic movements. If you have any questions, please feel free to ask. If you would like me to test other workouts, please feel free to ask. I will be happy to help you make an informed buying or returning decision. What did I do? Tread mill, jump rope (moderate and intense; regular skipping and double unders at roughly 30 second intervals), back rows  (machine and free weights), lateral raises (dumbbells), push ups. I consistently checked the Blaze against the Endomondo app with H7 monitoring. 

Review/Thoughts

The Blaze does an exceptional job tracking heart rate for exercises under ~155 beats (it does *rarely* have a spiked drop here and there, but generally it is right on). Once the heart rate goes above that, it is hard to know if it is accurate (which it sometimes was) or is hardly accurate (which it sometimes was). The conditions that gave me different results were the same: jumping rope. With regard to the weights, I did not have trouble with the device. It was within  approx. 5 beats of the chest strap. I believe the discrepancy while skipping rope comes from the Blaze's inability to quickly track a a pulse once it reaches the anaerobic zone. The sensor on the Blaze records your pulse every second and scans it many more times than that per second; however, it doesn't do a great job once your heart react reaches the 150s and up. Interestingly enough, Fitbit describes the peak zone at about 152... and that is right about where the device starts to lose credibility. A few times-I stress a few- it did keep up with the chest strap and go into the 160s, but there were many times when my heart rate was at 180+ and the Blaze was nowhere to be found (it was in the 150s).

Conclusion
Just like you'd expect, the Blaze doesn't do great with extremely intense exercises. However, if you are doing moderately intense to intense workouts, you can count on it to be pretty spot on, and I mean very, very close!!!! Below are the graphs of the workout. With that said, your calorie count is definitely going to be thrown off because the Blaze is less likely to put you in the anaerobic zone. Blaze had me at 473 while the H7 on Endomondo had me at 596.The top is the chest strap (with endomondo), and the bottom is the Blaze.

[AdamMSC]

The large spikes come from jumping rope inbetween my lifting sets. I really pushed the device to where it's most limited, and it did a decent job. It will do very, very well at tracking your heart rate throughout the day and for your moderately intense workouts!

[AdamMSC]

RETEST DAY 2; Different results:

Differences- I moved the monitor up about an inch on the arm.

I did a gradually increasing cardio workout to get my heart rate into the 180s. The Blaze performed phenomenally. Moving the Blaze up some also  made a difference in the HIIT with the jump rope. Instead of being off by 20+ beats at times, the Blaze with always within 10 beats. There is still room for improvement, but this device performs VERY WELL  for a wrist-based monitor. Once again, it had NO problem keeping up with weightlifting/ body exercises. Graphs below:

Conclusion: 

Arm placement makes a big difference... Also, the Blaze still undercounts the rapidly rising pulse, but it got right near it every time. There were instances when I thought that the Blaze was using the heart rate monitor to get its information; it was seriously spot on, and I was trying to mess it up... So I am going to leave my previous review up (so people can see the difference in placement), but this one is going to be my final take on it. The Blaze gets an A for accuracy...

[bbarrera]

Objectively those results are not phenomenal, there is a serious enough accuracy gap that would prevent me from using it for HR training on bike or running. Just look at the shape and min/max HR on the last three "bell curves" at 10min, 13min, and 15min marks. The Blaze would push me out of my training zones in past threshold. Go read DCRainmaker's reviews and you'll find there are better optical HRMs in the market.

[AdamMSC]

Fair enough! I've read his review; it is very good and much more comprehensive than mine. However, the crap some people are posting about the hr monitor just isn't true... It is PLENTY accurate for anybody that wants a good estimate of a workout and a near perfect picture of their general daily heart rate trends.

[AdamMSC]

Those last three curves all come from jumping rope btw ... I think it did a pretty good job with it. If I started doing cardio again on the treadmill again, then I guarantee it would've been within a beat or two!

[SunsetRunner]

I agree with @bbarrera, the Blaze is good enough for a daily overview but if training with heart rate zones, it's no good (which is why we have chest straps 🙂 ) The Blaze would not be able to tell me the moment or indeed time I was in UT AT TR or AN zones.

[AdamMSC]

I am a novice when it comes to this stuff, and I am sure you have plenty of experience with it, so please help me understand why the device would fail as a training tool after reading my thoughts on it below.

The Blaze was precise each time I used it on the treadmill. I would guess it would be just as accurate on a bike, but I haven't tested it yet. I've read from Runners World that there are studies done where running by feel and the talk test is well correlated with a targeted pace... If that is good enough for some people, then the Blaze can certainly work as a tool. Since zones have about a 5-10 percent margin, they are more like guidelines than they are precise and exact rules. I am not saying they are irrelevant or unimportant! But since the Blaze is the exact same when doing cardio while being compared to a chest strap, one would be getting something more than just a correlation... They'd be getting that and an effectively accurate device. The only issue I could see is that it can be  off by 10 beats (or less)  while doing HIIT... but that isn't a typical cardio workout. If given time, the monitor does catch up on the Blaze...

[KiloLima64]

In my opinion this device is for the everyday person. If you training for a marathon or are a "Super" athlete then you wouldn't use this product you probably turn to something more serious like a Polar with a chest strap. For the everyday person 10 beats per minute difference isn't that much of a gap.

[AdamPow]

I don't think Fitbit is targeting Olympic athletes in training. It's a great device for recreational and semi-serious athletes. 

Next time you walk through the gym, take a look at the people working out. What percentage actually get their heart rate above 155 bpm? Of the ones that do, what percent of their workout are they above that level? You're talking about a small amount of people for a small segment of their workout. 

[SunsetRunner]

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@AdamMSC wrote:

please help me understand why the device would fail as a training tool after reading my thoughts on it below.

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Quite simply, yes it is good for average use but if training in zones, these zones need to be accurately monitored. My anaerobic threshold band is 163 - 168bpm. Clearly a 10bpm error isn't going to cut it.

Also, today I noticed the Blaze just gave up and flat lined my HR. Again, no help at all. But, I acknowledge that the training I'm doing is not what the Blaze is for and so have the chest strap. But I do have the Blaze for the rest of the day, and I'm happy with what it does there.

[AdamMSC]

I agree with what you all are saying: most people wouldn't use it for serious training. People that are serious have generally decided to invest in more serious equipment. However, it could be used as a tool for someone who is serious about their health, and there is an important difference there... it is good enough to be used as an effective tool, and it is spot on while compared the the Polar chest strap that I have when doing cardio. That being the case, it could be used  for zone training. One doesn't  need to be a serious athlete to target specific zones.

[AdamMSC]

@SunsetRunner 

Weird. I haven't experienced a flatline yet. I have had it drop my heart rate quicky to try and match what it actually was, though. So would you agree that-- when it is working like it's supposed to and can-- it is as accurate as a chest strap while doing cardio? I've yet to see mine be off by more than a few beats while running...if it is, then it quickly catches up. I have both, so it doesn't matter much to me if the Blaze is perfect; I am just reporting the results that I've gotten... and they suggest that the Blaze is spot on for cardio. I will do more tests this week and show more graphs. Next time I will do sprint intervals and see how it fairs.

[SunsetRunner]

No I wouldn't agree it's good enough for zone training @AdamMSC. It's alright for cardio work if all you're doing is "exercise", as you're not going to be that bothered where your hr is. And to be fair, it is generally good at that, assuming you get it positioned correctly and nothing moves it too much. However for high hr work, where I'm monitoring aerobic / anaerobic thresholds, it's not up to the job, especially if there's a lot of movement of my wrist, which impacts the Blaze's ability to interpret the light readings. As you say, it's playing catch up and that's not good enough. But I'm ok with that, as I have the tools that are.

[AdamMSC]

Fair enough. I am interested to see how it does with sprints and interval training while running. I think it will do much better there than it did while I was jumping rope.

[bbarrera]

It wanders and sometimes loses HR, even on steady state cardio. Read the DCRainmaker review. 

[AdamMSC]

I have read it. I haven't had any wandering yet.There is at least one person with one problem for each part of the device... For every person that has a problem, there seems to be another one that doesn't and finds it to work just fine. There is a concentration of the bad here because people go to forums to look for solutions; however, just read the amazon reviews to see all the positive at the other side of the spectrum. I am telling you that I have not had it wander while doing cardio, nor have I had it drop while doing cardio. It has been dead on!

[SunsetRunner]

Well I'm definitely not impressed. Did 25mins @ 165-170bpm (Polar) and Blaze had me 119 - 165, with no continuity. It was up and down, though mostly down.

[JeffWski]

I've found the Blaze to be horrible at interval training. 2 of the 3 cool down segments for one of my workouts the Blaze actually said my HR went up! My chest strap correctly showed the decrease in HR. Like others have said, I feel the HR is adequate to a point. It definitely struggles with high intensity and intervals.

[bbarrera]

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@AdamMSC wrote:

I am telling you that I have not had it wander while doing cardio, nor have I had it drop while doing cardio. It has been dead on!

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Your graphs clearly show it was *not* dead on compared to chest strap. Optical HR monitors on the wrist are pretty darn good when you are at rest, and do ok when exercising - very good from time-to-time and struggling at other times. Its ok to admit it, your comparison, and others that have taken the time to compare with chest strap, clearly show that accuracy during various exercises is an *estimate* that can be hit or miss depending on when you look.

Its all good, some folks want a better looking Fitbit and will upgrade to Blaze. But the Fitbit marketing claims of PurePulse are often a case of "over promising and under delivering." If this was Apple those claims would be torn apart on the Internet. But its Fitbit, the market leader, and for some reason judged on a different, more lenient, standard.