Fitness tracker reliability

MeanderingMammal

So contest to the received wisdom, not bad at measuring HR, but poor for calorie estimation.


Fitness trackers out of step when measuring calories, research shows | Technology | The Guardian https://www.theguardian.com/technology/2017/may/24/fitness-trackers-out-of-step-when-measuring-calories-research-shows

RDahling

Of course they are off - it's not really contrary to any conventional wisdom since most fitness trackers come with a caveat clearly stating they aren't perfect and are not a replacement for gold-standard testing, and that alterations to diet and lifestyle should be done in consultation with a doctor.

MeanderingMammal

RDahling wrote: »

...it's not really contrary to any conventional wisdom...

It shouldn't take long browsing around the forums to identify that there is a perception that they're more reliable than they are.

To me, what's interesting is that the HR monitoring aspect is pretty stable. Many on here will condemn optical HR tracking as unreliable, when in practice it's good enough for most use. All that said the article doesn't comment on the inappropriateness of HR sensing as a proxy for calorie expenditure in the first place.

..... aren't perfect....

I'd observe that the marketing suggests something very different. Caveats buried in the instruction manual have significantly less effect than TV and Farcebook advertising.

Ann262

I think that is common sense. The tracker only knows the data you entered when you bought it, your heart rate and your movements. I think they are useful for a high level guidepost to comparing day to day expenditures but I never thought they were good enough to take to the bank.

Theo166

MeanderingMammal wrote: »

RDahling wrote: »

...it's not really contrary to any conventional wisdom...

It shouldn't take long browsing around the forums to identify that there is a perception that they're more reliable than they are.

To me, what's interesting is that the HR monitoring aspect is pretty stable. Many on here will condemn optical HR tracking as unreliable, when in practice it's good enough for most use. All that said the article doesn't comment on the inappropriateness of HR sensing as a proxy for calorie expenditure in the first place.

..... aren't perfect....

I'd observe that the marketing suggests something very different. Caveats buried in the instruction manual have significantly less effect than TV and Farcebook advertising.

Many post first hand accounts about how their optical HRM fails to work correctly during strenuous activity. I like my FB for daily wear but think there is no substitute for using a chest strap HRM when you are seriously training.

NorthCascades

MeanderingMammal wrote: »

To me, what's interesting is that the HR monitoring aspect is pretty stable.

My Fenix 5X's optical/wrist HR sensor reports a perfectly stable 120 bpm when I'm running above my threshold which is 165 bpm. A stable number isn't useful if it's the wrong number.

NorthCascades

By the way, this was already posted here:

http://community.myfitnesspal.com/en/discussion/10559703/fitness-trackers-are-largely-inaccurate-when-counting-calories-stanford-researchers-say#latest

MeanderingMammal

Theo166 wrote: »

MeanderingMammal wrote: »

RDahling wrote: »

...it's not really contrary to any conventional wisdom...

It shouldn't take long browsing around the forums to identify that there is a perception that they're more reliable than they are.

To me, what's interesting is that the HR monitoring aspect is pretty stable. Many on here will condemn optical HR tracking as unreliable, when in practice it's good enough for most use. All that said the article doesn't comment on the inappropriateness of HR sensing as a proxy for calorie expenditure in the first place.

..... aren't perfect....

I'd observe that the marketing suggests something very different. Caveats buried in the instruction manual have significantly less effect than TV and Farcebook advertising.

Many post first hand accounts about how their optical HRM fails to work correctly during strenuous activity. I like my FB for daily wear but think there is no substitute for using a chest strap HRM when you are seriously training.

Indeed, and clearly anecdata > lab testing...

Fwiw I wouldn't consider any of the devices listed for serious training anyway.

MeanderingMammal

NorthCascades wrote: »

By the way, this was already posted here:

http://community.myfitnesspal.com/en/discussion/10559703/fitness-trackers-are-largely-inaccurate-when-counting-calories-stanford-researchers-say#latest

Well it would have been, had I not posted this on the 25th...

CharlieBeansmomTracey

I have found too that the HR on a fitbit can be off compared to if you measure manually. sometimes by up to 10bpm.even more if you are working out.I just know once my fitbit dies Im never buying another lol

jenniferinfl

MeanderingMammal wrote: »

So contest to the received wisdom, not bad at measuring HR, but poor for calorie estimation.


Fitness trackers out of step when measuring calories, research shows | Technology | The Guardian https://www.theguardian.com/technology/2017/may/24/fitness-trackers-out-of-step-when-measuring-calories-research-shows

Of course, they are still just calculated based of population averages which means that they won't be consistent for everyone. Pair it with a website like trendweight though and you will have a very handy tool.

My activity varies, I have a desk job, my TDEE should be around 2000 calories per day. But, I'm a fidgety person, I get more like 10,000 steps a day at my sedentary desk job. When I eat at a 1000 calorie deficit based on my Fitbit Blaze's data, I lose at a rate that indicates my actual deficit is 759 calories a day. (Last week it was 638, I found the inaccurate nutrition label, precooked chicken that was actually higher in calories than the label) I'm eating above my estimated TDEE and losing at a rate that indicates I'm at a 759 calorie deficit. Because, oh yeah, not all desk jobs are quite the same. Other people doing the same job as me, my coworkers, only get around 3500 steps per day. But, like I said, I'm nervous and fidgety. My experience is different.

You can make anything not work for you. I have friends who do dumb stuff like put their activity tracker on their ankle to make it track their recumbent bike.

Or, you can sign up for a site like trendweight, log your food accurately and determine how close your activity tracker is for you and then adjust accordingly and have an excellent tool.

Though, I suppose if you do the same activity everyday, then you could just skip the activity tracker and figure out your TDEE by logging and using trendweight. My activity varies widely though, so, the activity tracker is a better choice for me. When I walk 13 miles at Disney I need to know how many more calories I should eat, my Fitbit Blaze lets me do that very accurately because I've done the math to make it work for me.