Fitbit Charge HR - Lower and Upper HR zone - what does this mean?

kmaf2018

Hi Everyone

So I recently purchased the Fitbit Charge HR and I really like it, however, the HR zones are really confusing me.

So my resting heart rate is 58bpm but it seems fitbit calculates your Target HR Zones using the "220 minus age" method (mine would be 188bpm) which then sets the Target Zones as Fat Burn 94-131bpm, Cardio 131-159bpm and Peak 159+bpm but according to my calculation based on my RHR, my Target Zones should be Fat Burn 136-149bpm (60-70%), Cardio 155-162bpm (75-80%) and Peak 162-175bpm (80-90%).

There is an option to "custom" your zones but only gives a "lower" and "upper" option - and if I put lower option as 136bpm and upper as 175bpm, it still doesnt look right, the graph!

Please can anyone help as its beginning to annoy me not knowing if my workouts will be recorded as accurately as can be :-(

Kel

NorthCascades

Beth had a Fitbit Charge HR for a while (returned it). It uses a simplified 3 zone system to help people avoid being confused. It's not really meant to serious exercise.

kmaf2018

Thanks but what defines serious exercise? I attend the gym everyday mon-fri....is this defined as serious exercise therefore its pointless me having a fitbit?

clairecoffeehouse

Fit bits are very inaccurate if you scramble eggs it records as steps ffs

kmaf2018

Im not fussed about the steps to be fair! I read lots of great reviews about the fitbit, maybe I shouldve done more research but I suppose none of the HR watches etc are 100% accurate

NorthCascades

KMAF00 wrote: »

Thanks but what defines serious exercise? I attend the gym everyday mon-fri....is this defined as serious exercise therefore its pointless me having a fitbit?

Serious exercise is what's important to you. I guess if it's important enough for you to want to track it, and the equipment you have isn't working for you, that's an issue.

What Fitbits are good at is counting steps, and guestimating how many calories a person burns from walking and maybe running throughout their day. For some people, it's good at motivating them to walk more. But, outside of that, it's less useful, it isn't programmed to understand lifting weights or using an elliptical or a bike. Its heart rate monitor is not the best out there, either in terms of accuracy, or usefulness eg it can't broadcast the HR it measures to a bike computer, and you can't set up your zones the way you want to.

kmaf2018

Thanks for your response! I suppose the only reason I wanted it is so I could monitor my HR when doing my workouts so I knew I was in the "fat burn" zones! You often hear your HR should be this and that to burn fat and from what I was reading people deemed it an accurate HR monitor

LAT1963

If you decide to change products consider the Polar A360. It has added benefit of being waterproof/swim friendly and it establishes heart rate zones based in part on a resting heart rate measurement. It has constant monitoring of heart rate (which my A300 lacks) but it may require a chest band to measure heart rate while swimming.

HermanLily

I love my Charge HR 2, I love the data I get, I love the motivation it gives me.
I have a high end device, and they are both fairly close in their data.

HermanLily

The lower number, is a number you set for your heart rate, you don't want to go below this.
The higher number, you don't want to have a heart rate above that.

NorthCascades

KMAF00 wrote: »

Thanks for your response! I suppose the only reason I wanted it is so I could monitor my HR when doing my workouts so I knew I was in the "fat burn" zones! You often hear your HR should be this and that to burn fat and from what I was reading people deemed it an accurate HR monitor

A few things:

(1) Chest straps tend to be more accurate at measuring HR because they pick up the electric activity that causes your heart to beat, instead of shining a light into your wrist and trying to "see" when your blood vessels dilate, using a primitive camera.

(2) The "fat burning zone" is a real thing, but it doesn't work anything like you'd expect from the name. It's a useful pacing tool for endurance athletes during long events. What it means is that in the short term your energy comes mostly from fats not from sugars, which is important on a 100 mile bike ride because you only have so much sugar but fat is virtually unlimited. In the long term, a calorie deficit will come from fat. If you exercise and burn mostly sugar (glycogen) your body will replenish it later, and while you recover from the exercise, the energy cost (calories) will ultimately come mostly from body fat.

kmaf2018

@HermanLily when you say lower number is this my 136bpm and the higher number would by my 175bpm? (Sorry)

MeanderingMammal

KMAF00 wrote: »

Please can anyone help as its beginning to annoy me not knowing if my workouts will be recorded as accurately as can be :-(

What sort of training are you doing and what data do you want to be "accurate"?

janejellyroll

clairecoffeehouse wrote: »

Fit bits are very inaccurate if you scramble eggs it records as steps ffs

Unless your job is actually scrambling eggs, I find it hard to believe that this would add enough steps to make a significant difference over a 24-hour day.

kmaf2018

@MeanderingMammal Nothing in particular but Im loving the HIIT circuits that Im doing at the moment as of course I want to lose fat bit wanted to make sure I was in the "fat burning" target heart rates, I also do GRIT classes and kettlebell classes and like today in GRIT I kept checking my HR on my fitbit to ensure I was in the zone and I felt it made me work harder which made me feel good but then the target zones set on my fitbit threw me a little which really confused me! I also like how it measures your sleep (I know some will say its inaccurate) but I am such a poor sleeper that even if its only 50% accurate it gives me an indication of crap my sleep is and Im currently working on that now! The data I would love to be most accurate would be my HR zones when exercising

NorthCascades

janejellyroll wrote: »

clairecoffeehouse wrote: »

Fit bits are very inaccurate if you scramble eggs it records as steps ffs

Unless your job is actually scrambling eggs, I find it hard to believe that this would add enough steps to make a significant difference over a 24-hour day.

I think the idea is that while scrambling eggs might only account for 20 minutes of your week, this opens up questions about what else is being miscounted.

MeanderingMammal

KMAF00 wrote: »

... Im loving the HIIT circuits

The data I would love to be most accurate would be my HR zones when exercising

What I'd say is that HR zones aren't really all that meaningful in the context that you're describing, but if you do want to use it for motivational purposes I'd suggest a proper training device rather than a FitBit. If you're doing the HIIT then HR lag becomes an issue and while optical HR is ok for many people this is one area where a chest strap has an advantage.

Going back to the question of what the zones mean, you're into being to do some stress testing to establish your real maximum, lactate threshold and aerobic threshold. Without that you're really looking at relatively arbitrary values.

MeanderingMammal

clairecoffeehouse wrote: »

Fit bits are very inaccurate if you scramble eggs it records as steps ffs

All step trackers will give a degree of false positives. The design needs to balance false positives with lack of sensitivity. I cycled 10 miles this morning. My tracker registered steps, through stem and fork vibration. If it was desensitised so that i don't get the false positives, how much movement would it miss?

janejellyroll

NorthCascades wrote: »

janejellyroll wrote: »

clairecoffeehouse wrote: »

Fit bits are very inaccurate if you scramble eggs it records as steps ffs

Unless your job is actually scrambling eggs, I find it hard to believe that this would add enough steps to make a significant difference over a 24-hour day.

I think the idea is that while scrambling eggs might only account for 20 minutes of your week, this opens up questions about what else is being miscounted.

In my experience, not much else. When I got my Fitbit, I was curious about this and I frequently checked my step count after cooking, typing, playing video games, and similar activities. The only thing I've found that seriously throws off my step count is driving (which I rarely do). Whisking eggs or other food may add a few steps, but the impact in a 24-hour day is truly not significant for me. Fitbit also has dominant hand features that help minimize the impact of accidental steps.

I'm not saying it's accurate in every way (the stair climbing features is wildly inaccurate for me), but I disagree with the point made above.

sarabushby

Ironically you will 'burn more fat' by NOT being in the 'fat burn zone' but by being above it, if you trained for the same duration that is, since you will burn more calories in a higher HR zone. It's a common misconception that for weight loss you would want to be in the fat burn zone.

I find my Fitbit Charge certainly is not consistent with my HR from my chest strap when measured during significant exercise - spin class, run etc. It can be as much as 20bpm different and I am confident that the chest strap is the more accurate / correct of the two since I use two different chest strap HRMs.

I believe even Fitbit themselves acknowledge that the wrist HR sensors are not accurate for athletes wishing to train by HR and that instead it is more accurate during rest or moderate activity such as walking.

NorthCascades

janejellyroll wrote: »

In my experience, not much else. When I got my Fitbit, I was curious about this and I frequently checked my step count after cooking, typing, playing video games, and similar activities. The only thing I've found that seriously throws off my step count is driving (which I rarely do). Whisking eggs or other food may add a few steps, but the impact in a 24-hour day is truly not significant for me. Fitbit also has dominant hand features that help minimize the impact of accidental steps.

I'm not saying it's accurate in every way (the stair climbing features is wildly inaccurate for me), but I disagree with the point made above.

It sounds like you took the time to get to know your device before you started relying on it. Like you found its strengths and weaknesses so you'd have a better idea of how much trust to put in it and when to doubt.

My Garmin doesn't pick up false steps for driving, but sometimes I'll clear the lazy alert by scratching my cat's ears.