Finding Accurate Heart Rate Zones

[WavyDavey]

I was talking to my doctor about using fitbit. He was interested in the heart rate tracking, and I began to tell him about fitbit's HR Zones, Fat Burn, Cardio, and Peak. As I understand it, these are set in the tracker to 50-70% MaxHR for Fat Burn, 70-85% MaxHR for Cardio, and above 85% MaxHR for Peak.

He said just taking a percentage of the MaxHR is an outdated method, and I should be using the one as listed here: http://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/exercise-intensity/art-20046887?pg=2

Below I'll post the data for each method. What concerns me outright is that the new model has much higher BPMs need, especially for the fat burn and cardio zone. In fact, if my math is correct, what Fitbit considers Cardio is really just Fat Burn by Mayo's scale.

What do you think of this? Am I missing a glaring error here? Am I shorting myself by sticking with Fitbit's "outdated" method of calculation? Any thoughts appreciated.

Heart Rate Zones

MaxHR = 172
RestingHR = 70
HRReserve = 102


                                   Fitbit (% of MaxHR)            Mayo ([HRReserve X % of MaxHR] + RestingHR)

        85%-100%    146-172bpm (Peak Zone)             157-172bpm (?)

        70%-85%        120-145bpm (Cardio Zone)        141-156bpm (Vigorous)
                
        50%-70%        86-119bpm (Fat Burn Zone)        121-140bpm (Moderate)

[A_Lurker]

Hmm... interesting.  I'll admit I don't pay much attention to the training zones.  I work out, I burn calories, I lose weight.  The system you linked to makes more sense as it uses your resting rate in the calculation, but I did see the following in the article:  "Generally only elite athletes are concerned about this level of precision. They may also use slightly different calculations that take into account gender differences in target heart rate zones. These differences are so small that most casual athletes don't need separate calculations for men and women."

I definitely don't fit into that category so for the moment I'm okay with how my zones work out.  You can go into your settings and add your calculated zones in as a min/max for training though if you want.

[WavyDavey]

Yes, they state the small difference is mostly applicable to elite athletes. My problem is the difference between the two methods is anything but small. When I'm chugging along in Fitbit's cardio zone, I'm still in the "fat burn" zone on the 2nd method. The newer method doesn't even consider Fitbit's "fat burn" to even be exercise at all.

This kind of bugs me, if fitbit cardio is really just fat burn, and fitbit's peak zone is really mostly cardio. I care because I do HIIT training where I need to be at 85+%, and I'm starting to question where that is. It would be nice if fitbit allowed editing of the actual values for fatburn/cardio/peak.

Thanks for the suggestion to make a custom zone for a single workout. That's a good idea. Mostly, I thinik the way you do @A_Lurker, in that the calories in and out make all the difference at the end of the day.

If I put on my tinfoil hat, I'd guess fitbit purposely lowered the zones to encourage people to get started with fitness/weight loss?