My zone or fitbit

[Kevinp1983]

I was at the gym this evening. Where I attended a rpm class .

The instructor is pushing these new my zone belts. I already have the fit bit blaze.

So we decided to do an experiment.

I wore both and tracked my progress

The heart rate measurements were roughly the same. But what was different. Was the calorie burn.

My zone says I was 750 ish

Where fit bit says I was 450ish

Which one of the two do I trust?

[Kevinp1983]

Have pics of both workouts to prove.

[bbarrera]

@Kevinp1983 RPM class is stationary bike class, right? I haven't had good luck with Fitbit and spin/RPM or cycling. You can read about the same on DCRainmaker reviews of both Surge and Blaze.  Assuming you properly setup MyZone account, I would trust their chest strap which has been benchmarked to EKG and is 99.4% accurate. Fitbit makes no claims about accuracy.

Keep in mind these are calorie burn estimates based on heart rate, generally accurate for majority of people (there are research papers easily found if you are interested). Your actual calorie burn might be different. Also, when you are training in upper ranges of your heart rate zones, "roughly the same" is not good enough. Thats why you want a chest strap.

[Kevinp1983]

It's a bit frustrating. I hear statements saying you shouldn't Base any fitness/nutrition programs around the results of the analysis.

But what's the point if you don't? Might as well not buy one.

I personally bought one. To see what sort of calorie burn I was achieving daily. So I could fine tune a diet. I didn't expect it to 100% spot on. But 300 calories difference. Can be extremely crucial.

I'm disappointed.

[bbarrera]

Personally I've found 24x7 HRM to be more of a distraction and a reason to lose sight of the fundamentals.

My BMR calorie burn for the day is about 1850 cals. Walking around 10,000 steps throughout the day burns somewhere between 200 calories (pacing around office) and 500 calories (45-60 min dog walks) additional calories. So on typical days I start with eating around 2000 calories, and add more calories when exercise level increases.

Exercises of choice are cycling, weight lifting, and spinning/RPM in winter. I burn 700-1200 calories per hour while cycling (great bang for the exercise buck), and I typically ride a total of 5 hours mid-week, so thats 3500-6000 calories burned mid-week. On weekends another 3-5 hours on the bike, for another 2100-6000 calories on Sat/Sun. On the low-end (5600 cals/week) that works out to eating another 800 calories per day during the week, and on the high-end that works out to eating another 1700 calories per day. When I'm out riding hard 5 days a week, or have a big century ride on the weekend, my body tells me its not getting enough to eat.

Its not an exact science, with or without all-day HRM. Stuff like this has been around for awhile:

http://www.webmd.com/diet/estimated-calorie-requirement

I'm the last line of the chart. If you've been following what's missing from that chart is a "very active" column.

With Fitbit I counted calories and walked to lose first 30 pounds (out of 40), then got fit and couldn't walk fast enough. So I started cycling and had trouble maintaining weight because Fitbit underestimated calories. Result? Wasn't eating enough and weight dropped too fast. That was before Surge/ChargeHR/Blaze hit the scene. My only option was to buy a chest strap to get better handle on how much I burned while riding. I'm a big guy (burn more cals), and ride hard, often 80-90% max heart rate in very narrow HR zones, and for that reason am not giving up the chest strap because it is accurate. Before dinner I pull up ride in Strava, review calories burned, and make tweaks to dinner portions. Don't always get it right, and my body lets me know if I'm not eating enough, and the scale does the same if I'm eating too much.

If Blaze works for you thats great. But if not don't forget the fundamentals.

Hope that helps.

[Rich_Laue]

Both units use their own proprietarysth to figure calorie birn.. Without monitoring the O2 consumed it would be hard to tell which one is closer
I've been told Fitbit does not add your BMR to the exercise, if this is true than some,not all, of. He difference would be explained.

[bbarrera]

"if this is true than some,not all, of. He difference would be explained."

"some, not all" isn't that much -- if Fitbit doesn't add BMR, then assuming 1 hour workout for male/200lbs/50s you are only adding 78 BMR calories:

original diff: 450/750 = Fitbit calorie estimate is 40% lower than MyZone

adding BMR to Fitbit: 528/750 = Fitbit calorie estimate is 30% lower than MyZone

Still a big difference: 300 vs 212 calories.

Reasoning behind my assumptions: I typically burn 750 calories in a one hour spin class, unless I go all out then I burn around 1200 calories in an hour. This online calculator:

http://www.acaloriecalculator.com/calories-burned-calculator/

is pretty handy for helping to compare the calorie burn estimates from HRM against compiled/generalized data. Its been fairly accurate for me, at least for walking, hiking, cycling, and stationary bike in gym (ours have power meters, easy to lookup in table from that website). It may not be that accurate for you, so compare with a grain of salt. 

[Ukase]

Sorry this reply is so late, but maybe it can help someone. 

 MyZone is allegedly 94% as accurate as an EKG. Not sure what Fitbit's stats are, but odds are, the MyZone is more accurate. That said, consider that when you first try on a Fitbit - presumably you've already loaded your age, height, weight, etc. With MyZone - it sets you up with a resting heart rate of 100bpm, and adjusts from there. Usually in a day. So - the calorie reading you get on that first demo isn't a good comparison. Additionally, MyZone uses your max heart rate to determine what "zone" you're in when you're exercising and attributes your calories based on that percentage of max heart rate. 

Suppose you're in great shape for someone your age? MyZone isn't going to know that for another month or two, when it detects that you might be staying in the 90-100%% range longer than you should be able to, and it will adjust your max heart rate upward. These variables will certainly impact your total calorie results. 

I noticed that Fitbit overestimates walking/running compared to MyZone, and Fitbit underestimates other non-walking/running workouts. 

The truth likely lies somewhere in between. 

[Rich_Laue]

Which type of My zone device dosyou have? Does it go around the chest and read the electrical impulses that an ELF would read? Or does it go on the wrist and looks at changes in the density of blood. 

I'm afraid that a chest strap will almost always be a little more accurate. 

As for calories burnt. this accuracy will be based on the math 

[jazzybelle]

I think the my zone is more accurate because of the 94% stated accuracy on their webpage, but also bc the fitbit doesn't really calculate the calories from the minute u start ur workout unless your pressing the button on your blaze to start you workout.  I used to box with a fitbit blaze and now i box with a myzone, I think the fitbit might calculate everything overall through the day.  but the myzone will show accuracy through your whole workout in comparison.  I used to add the calories by the minute on the fitbit app to get a better accuracy for the hour worked out.  with myzone soon as you put it on it starts counting the heartrate and calculating calories to the minute u take it off.  good luc

[raevont]

I am a long time FitBIt user and I currently have the Versa 2 with a premium subscription. I got a MyZone Chest Strap over the summer to use at my gym during cycle class (mostly to be competitive LOL). What I have consistently found is that my FitBit calories burned is almost 100 points less than the MyZone strat/app. The reason, I have found, is that, my Versa regularly stops reading my heart rate during exercise (especially on the "weights" setting) thus the gaps in measurement cause my calories to be lower. I have spoken with tech support numerous times and followed their recomendations of specific wrist placement, resetting the HR on/off in settings and restarting the device. I've done these things multiple times and my Versa 2 STILL stops reading my HR rate randomly during my workout. I will continue to use this Versa 2 until it dies. After using MyZone for 6 months now, I feel it is the superior choice for HR monitoring and calorie burn if that is what you are focused on. FitBit does have superior options in the way of the app, including premium features/workouts/minfulness settings, etc, so if thats what matters more, then stay with FitBit and take your calories/HR as a suggestion.