Polar FT7 - Fitness and fat burning zones...

FCFitness75
FCFitness75 Posts: 35 Member
edited November 2024 in Fitness and Exercise
I've recently bought a Polar FT7, and while I known HRMs can't be totally accurate, I'm just using it as an aid alongside my exercise classes and not eating back as many calories as it says I've burnt off. I'm a bit confused though, because at the end of a class it says I spend a really little amount of time in the 'fat burning zone' and most of my time in the 'fitness zone'. I looked this up and it seems that the 'fat burning zone' is when you train at a lower intensity than the 'fitness zone'... What does this mean? What is the science behind it? I can't believe that just because I like to train hard it would mean that I'm not burning fat... Can anyone shed some light?

Replies

  • jrcrmr
    jrcrmr Posts: 31 Member
    It's all nomenclature.

    But specifically, it is called the "fat burning zone" because it's the optimal amount of calories burned for the amount of effort you put in. Meaning that even if you went, let's say, 30BPM more, the amount of caloric burn you get would not be significant versus to amount of effort you're putting in.

    That being said, the fitness zone is "better" to train your cardiovascular fitness. Your heart is working a bit more and therefore, your "rest" rate will be a tad lower and progressively, you will be able to put same effort (e.g. same heart rate) while doing longer distances faster (this is over the course of long periods of training, of course). You will still burn calories in the fitness zone versus the fat burning zone (you actually burn MORE calories in the fitness zone, but if your goal is fat loss, and to get "most bang for your buck" with regards to caloric deficit, people aim for the fat burning zone), it's just the relative amount of calories loss versus effort in the two zones are different.

    hope that makes sense/helps.
  • sijomial
    sijomial Posts: 19,809 Member
    It's a pointless distinction that should have died out in the 1980's.

    It relates to the fact that you burn a higher proportion of fat in lower intensity exercise, at higher intensity the proportion changes to little fat and mostly glycogen. A sliding scale and not two distinct zones anyway.

    And the significance of that for weight loss/fat loss is precisely nothing. What matters is your calorie balance over the course of a day and not what you are fuelling your workouts with. Total calorie burn is far more significant (for weight loss).

    Heart rate zones have significance for serious cardio training but it's far more complex than most people need.

    Wish Polar would drop it!!
  • FCFitness75
    FCFitness75 Posts: 35 Member
    Thanks very much jrcrmr! So I still burn calories in the fitness zone, but in the fat burning zone, it essentially takes less effort to burn the same calories? I'll just keep training hard then because I want to improve my stamina and ability anyway in addition to burning fat :)
  • demonwithahalo
    demonwithahalo Posts: 11 Member
    The "fat burning zone" is a myth. The higher the intensity of your workouts, the more calories you are burning. Keep at it as you are.
  • FCFitness75
    FCFitness75 Posts: 35 Member
    Thanks sijomial. I do think it's an unnecessary complication that might surely give people who aren't as nerdy as me reason to believe that they can just not put as much effort in. I was skeptical of the feature when I bought the FT7, but didn't plan on using that part much anyway because I just wanted something to track 'total calories burned' as opposed to what 'area' they were being burnt from.
  • Whittedo
    Whittedo Posts: 352 Member
    All my answers have already been given. I have a Polar M400 and like you I don't completely trust its calorie burn numbers. I usually log 80% of their calculation.
  • jeichelb83
    jeichelb83 Posts: 172 Member
    I do the same thing as Whittedo. I only take 80% of any machine readout whether it be an excercise bike, elliptical, stepper, HRM, or some other gadget.
  • FCFitness75
    FCFitness75 Posts: 35 Member
    Yeah I've been doing the same sort of thing, I log about 75%. I'm very short and don't weigh a huge amount, so my calories burnt are never these impressively high numbers a lot of users of MFP seem to get, but for example, yesterday I did Insanity for 60 minutes and it said I burnt around 400. I logged 300 just in case, and today I did a half hour HIIT class which said I burnt 200, so I logged 150. :)
  • Cronniss
    Cronniss Posts: 108 Member
    jrcrmr wrote: »
    It's all nomenclature.

    But specifically, it is called the "fat burning zone" because it's the optimal amount of calories burned for the amount of effort you put in. Meaning that even if you went, let's say, 30BPM more, the amount of caloric burn you get would not be significant versus to amount of effort you're putting in.

    That being said, the fitness zone is "better" to train your cardiovascular fitness. Your heart is working a bit more and therefore, your "rest" rate will be a tad lower and progressively, you will be able to put same effort (e.g. same heart rate) while doing longer distances faster (this is over the course of long periods of training, of course). You will still burn calories in the fitness zone versus the fat burning zone (you actually burn MORE calories in the fitness zone, but if your goal is fat loss, and to get "most bang for your buck" with regards to caloric deficit, people aim for the fat burning zone), it's just the relative amount of calories loss versus effort in the two zones are different.

    hope that makes sense/helps.

    Thanks for this.

    I just got the A300 and I had been wondering about this myself. I had a pretty good idea of what it meant, but I had just not had time to research it yet.

    89019335.png
    (Quote from "The Hitchhiker's Guide to the Galaxy" by Douglas Adams.)
  • MakePeasNotWar
    MakePeasNotWar Posts: 1,329 Member
    jrcrmr wrote: »
    It's all nomenclature.

    But specifically, it is called the "fat burning zone" because it's the optimal amount of calories burned for the amount of effort you put in. Meaning that even if you went, let's say, 30BPM more, the amount of caloric burn you get would not be significant versus to amount of effort you're putting in.

    That being said, the fitness zone is "better" to train your cardiovascular fitness. Your heart is working a bit more and therefore, your "rest" rate will be a tad lower and progressively, you will be able to put same effort (e.g. same heart rate) while doing longer distances faster (this is over the course of long periods of training, of course). You will still burn calories in the fitness zone versus the fat burning zone (you actually burn MORE calories in the fitness zone, but if your goal is fat loss, and to get "most bang for your buck" with regards to caloric deficit, people aim for the fat burning zone), it's just the relative amount of calories loss versus effort in the two zones are different.

    hope that makes sense/helps.

    Not quite true. A greater proportion of calories in the "fat burn" zone come from fat (dietary fat and body fat), but for weight loss, and even fat loss, it's total calories that matter. Fat burning is just the energy system; it has nothing to do with body fat level at the end of the day.

    Low intensity exercise needs fewer carbs to fuel it because slow burning fat is enough to sustain light activity. When intensity goes up, you need energy faster than fat can provide it, so you burn more carbohydrate.

    At the end of the day, every "leftover" calorie (not just dietary fat) is stored as fat, and every calorie shortfall is provided by releasing body fat (primarily). The more calories you burn, the more body fat you will lose in a day. Where those calories come from in the short term doesn't matter.
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