Fat Burn Zone

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LittleirishDevil
LittleirishDevil Posts: 2 Member
in Health and Weight Loss
Hi All,
My name is James and I am 48 years old and starting to get back in to exercise, my question is : I am trying to workout my fat burning zone based on my age, I have done the 220 - my age, which is 172 beats and then divided by 0.6 (60%) and 0.7 (70%) , so that is 103 - 120 beats for fat burning, I have just done 40 minutes on the stationary bike working between these figures but I didn’t feel I had done anything or broke a sweat, am I doing it wrong or have I got the maths wrong? Any advice would be greatly appreciated.

Many Thanks

James

Replies

  • apullum
    apullum Posts: 4,838 Member
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    The "fat burning zone" as the term is usually used is mostly myth. Your body burns fat when you are in a calorie deficit.

    During cardio, the body first uses its readily available energy sources: glucose in the bloodsteam, and glycogen stored in the muscles and liver. It then begins to burn fat as those other energy sources are depleted. Getting your heart rate into a particular range does not cause the body to skip these other energy sources and use fat first.

    Here is a plain English explanation that also links to a scholarly source: https://vitals.lifehacker.com/there-is-no-fat-burning-zone-1831641069
  • sijomial
    sijomial Posts: 19,811 Member
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    Fat burn is badly named and an irrelevance, or even counterproductive, for weight loss.
    It's based on the reality that at lower intensities you burn a higher proportion of fat to carbs (my personal 50/50 level was about 130bpm when tested in a sport science lab). That has some relevance for people doing very extended duration endurance cardio and trying to avoid running out of glycogen (bonking/hitting the wall).

    For weight loss your negative calorie balance over an extended period of time is what results in fat loss, what fuels you use during the exercise session simply doesn't matter. What you use gets replenished when you next eat anyway - both fat and glycogen storage are always in a state of flux.

    If you are using exercise to create a deficit (which isn't how this site is designed) then by limiting yourself to lower intensity you are burning less calories than if you pushed yourself harder. You are potentially also missing out on fitness improvements.

    Another thing to note is the 220 - minus your age max HR estimate may well be very inaccurate for an individual. My brother could hit 200bpm at 60!

    Exercise for health, fitness and enjoyment. Forget about zone training unless you are serious about an endurance sport. I wouldn't advise not eating back exercise calories either as that's a very short term view.
  • dmt4641
    dmt4641 Posts: 409 Member
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    I echo what others say about the fat burning zone being irrelevant. I think the intensity of your cardio should be based on how you feel, not what your heart rate is. If you are doing short intervals with high intensity, you should be breathless and not really able to talk during the internal. If you are doing longer steady state cardio, you should be able to hold a conversation that is just a few words here and there, but not a full blown gab session. If you could carry on a full conversation without a problem, increase the speed or resistance or both.

    I just wanted to add that heart rate gets much higher than those calculators say and regularly gets up to 190 or even 200 during high intensity exercise and I am pretty well conditioned. I have just always had a fast heart rate.

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