How accurate are HRMs/Fitbits?

mfm143

Hi all

Wanted to get some feedback on how accurate HRMs/fitbits really are? I have researched various models and have read a lot of conflicting info on their accuracy? I.e. only chest straps are truly accurate ? HRMs/fitbits are very inaccurate ( i.e. grossly overestimating cal/burn for regular activities -60min walking moderately boring 1000+ cal??) what are your thoughts ? All appreciated thanks !

cwolfman13

nothing is "truly accurate"...it's all estimation. HRMs are awesome at telling you what your HR is...but your HR isn't directly correlated to your calorie burns. You HR is just used in an algorithm that makes a lot of other assumptions which may or may not be more or less accurate. One of those assumptions is that you are doing a steady state aerobic activity...a good HRM is reasonably accurate for calorie burn (but still very much an estimate) for this type of activity...the further you get from this kind of activity, the less accurate it will be.

Fitbits and the like are equally just estimates based on your information, but also a lot of other assumptions.

there's no way you're going to burn anything remotely close to 1,000 calories for walking for an hour...more like 250 - 300 tops.

editorgrrl

The only way to gauge the accuracy of any device is to trust it for several weeks, then reevaluate your progress.

I eat back 100% of my Fitbit adjustments, lost the weight, and kept it off. But I also:
• enabled negative calorie adjustments in my diary settings,
• log exercise in Fitbit—never MFP, and
• log everything I eat & drink accurately & honestly.

mfm143

cwolfman13 wrote: »

nothing is "truly accurate"...it's all estimation. HRMs are awesome at telling you what your HR is...but your HR isn't directly correlated to your calorie burns. You HR is just used in an algorithm that makes a lot of other assumptions which may or may not be more or less accurate. One of those assumptions is that you are doing a steady state aerobic activity...a good HRM is reasonably accurate for calorie burn (but still very much an estimate) for this type of activity...the further you get from this kind of activity, the less accurate it will be.

Fitbits and the like are equally just estimates based on your information, but also a lot of other assumptions.

there's no way you're going to burn anything remotely close to 1,000 calories for walking for an hour...more like 250 - 300 tops.

Exactly my point - I have seen some in the community with similar stats as example above and keep thinking to myself there's no way that's accurate? I think it lends to the concept of consumerism - companies want to sell these things so hence the claims that they can accurately track your cal burned are inflated.

mfm143

editorgrrl wrote: »

The only way to gauge the accuracy of any device is to trust it for several weeks, then reevaluate your progress.

I eat back 100% of my Fitbit adjustments, lost the weight, and kept it off. But I also:
• enabled negative calorie adjustments in my diary settings,
• log exercise in Fitbit—never MFP, and
• log everything I eat & drink accurately & honestly.

I do not have a Fitbit or the like - and just use this method for what it's worth - recording 100 cal manually for the exercises I do ( 5x5 ICF 3x/wk & HIIT @30 min 2xwk ) I m pretty confident I am burning well over 100 cal per wo but just record bare minimums as a gage - really it's irrelevant as I generally do not eat back my exercise cals except for days I feel I need to - in which case I only eat about 40% back - so far my weight loss ( although slow) has been consistent.