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Fat burning zones, a question

TheBoyBillyTheBoyBilly Posts: 749
Another one of those "it's already been asnwered" questions, but I can't find it:
If my fat burning zone is in the region of 100-120 bpm on a HRM, what happens when I drop slightly below or above this range? Is this such a daft question? It's me so it probably is :oops:
To disagree with three-fourths of the British public is one of the first requisites of sanity - Oscar Wilde
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  • The only "fat burning" that goes on is on a BBQ with beer in hand. :D

    Suggest you search the forum for prior posts on the topic. In the meantime, read what's already been written....

    http://www.bikeradar.com/forums/viewtop ... t=12544454
    http://www.bikeradar.com/forums/viewtop ... t=12555742
    http://www.bikeradar.com/forums/viewtop ... t=12555663
  • Another one of those "it's already been asnwered" questions, but I can't find it:
    If my fat burning zone is in the region of 100-120 bpm on a HRM, what happens when I drop slightly below or above this range? Is this such a daft question? It's me so it probably is :oops:

    Hi there.

    I'll save you the effort - fat burning is a marketing myth. The more exercise you do, and the harder you do it, the more calories you burn. Your body stores all excess calories as fat, so if you burn more than you eat then you'll lose fat.

    Cheers, Andy
  • jenster88jenster88 Posts: 27
    I Have been told that the first 35-40 mins of any work out,you only burn off your carbs,then after that you will start to eat into the fat, proberly not the best technical terms but Is this true?
  • 3wheeler3wheeler Posts: 110
    At low intensity you are still burning fat or rather energy you are using is coming from your fat reserves, but you won't be burning many calories, just like me sitting down writing this I'm burning some calories :wink:

    Fat can only provide energy at a fairly slow rate, so when you exceed that your body needs to use the carb supplies, if you increase the intesity you are burning more calories but chances are the amount of fat being used stays the same.

    It's not quite so simple though because you will usually be getting your energy from a combination of sources, however in your 'fat buring zone' a high ratio will be coming from fat.
  • No it's simpler than that:

    Excess Calories = calories eaten - caloried burned.

    Excess calories stored as fat and vice versa. End of story.

    Cheers, Andy
  • 3wheeler3wheeler Posts: 110
    Andy - what you say is true in the long term, for example eat more than you use over a year and you will be fatter, but when you do exercise the type of exercise will determine where the energy comes from.

    So, if you did a series of sprints, you may have used energy, and be knackered afterwards, but most of that will have come from your glycogen stores not fat.

    Alternatively if you did a lower intensity, longer lasting session then a greater amount of energy will have come from fat.
  • oldwelshmanoldwelshman Posts: 4,733
    In simple terms Andy is correct but fat is burnt at different rates and different efficiencies depending on HR.
    It can also be dependent on metabolic rate and this can be higher after exercise in the morning.
    As far as I can remember working at high hr burns off more calories and more fat than lower HR but at a less efficient rate, but can also increase metabolic rate so benefit there also.
    Stay off the beer is best advice 8)
  • Stay off the beer is best advice 8)

    You got that right.

    Low intensity vs High Intensity. As I see it, the only advantage to low intensity exercise for weight loss is that you can do a lot of it without killing yourself - especially if you're new to the sport. The high intensity stuff will burn more calories per minute, and continue to do so after you stop and your body repairs itself.

    Hills, hills, hills is the answer to every question in this bit of the forum.

    Cheers, Andy
  • Andy, I think Hills is the answer to most general training conundrums!
  • I live in East Anglia there are no hills!!!

    Gats
  • ut_och_cyklaut_och_cykla Posts: 1,594
    I think both Andy & 3 wheeler are right.The fat burning zone is a myth - the best zone for it is when asleep! but clearly sleeping burns very few calories in total.....
    Doing hill training will burn loads of calories during & after from both fat stores and carbohydrates.
    Beginners start gently - eat a little less - and progress over time with increased intensity and time. For general fitness do a nice mix of exercise mostly bike 6 some running or vice versa - whatever you enjoy and can maintain - it's daily activity that keeps you healthy not slugging your guts out once a week.... :)
  • No hills = big chain ring, lower cadence into the wind. Plenty of wind over your way.
  • methodmethod Posts: 784
    Another one of those "it's already been asnwered" questions, but I can't find it:
    If my fat burning zone is in the region of 100-120 bpm on a HRM, what happens when I drop slightly below or above this range? Is this such a daft question? It's me so it probably is :oops:

    Hi there.

    I'll save you the effort - fat burning is a marketing myth. The more exercise you do, and the harder you do it, the more calories you burn. Your body stores all excess calories as fat, so if you burn more than you eat then you'll lose fat.

    Cheers, Andy

    So when I had some fitness testing done (v02 max etc) and it showed that I burn the most calories from fat at 138 bpm and none over 152bpm - your saying this isn't true?
  • method wrote:
    Another one of those "it's already been asnwered" questions, but I can't find it:
    If my fat burning zone is in the region of 100-120 bpm on a HRM, what happens when I drop slightly below or above this range? Is this such a daft question? It's me so it probably is :oops:

    Hi there.

    I'll save you the effort - fat burning is a marketing myth. The more exercise you do, and the harder you do it, the more calories you burn. Your body stores all excess calories as fat, so if you burn more than you eat then you'll lose fat.

    Cheers, Andy

    So when I had some fitness testing done (v02 max etc) and it showed that I burn the most calories from fat at 138 bpm and none over 152bpm - your saying this isn't true?

    Do you really need me to answer that for you?

    30 seconds with google reveals this: http://pinoyfitness.com/?p=8

    Cheers, Andy
  • methodmethod Posts: 784
    method wrote:
    Another one of those "it's already been asnwered" questions, but I can't find it:
    If my fat burning zone is in the region of 100-120 bpm on a HRM, what happens when I drop slightly below or above this range? Is this such a daft question? It's me so it probably is :oops:

    Hi there.

    I'll save you the effort - fat burning is a marketing myth. The more exercise you do, and the harder you do it, the more calories you burn. Your body stores all excess calories as fat, so if you burn more than you eat then you'll lose fat.

    Cheers, Andy

    So when I had some fitness testing done (v02 max etc) and it showed that I burn the most calories from fat at 138 bpm and none over 152bpm - your saying this isn't true?

    Do you really need me to answer that for you?

    30 seconds with google reveals this: http://pinoyfitness.com/?p=8

    Cheers, Andy

    Yes, probably why I asked you...

    But at an RQ over over 1, you aren't burning any fat right?
  • Tom ButcherTom Butcher Posts: 7,137
    My understanding is that if you are exercising at a high enough intensity then yes you are burning no or very little fat - from memory (so could easily be wrong) it's a high intensity - more sprinting than a short time trial type effort.

    it's a hard life if you don't weaken.
  • Tom ButcherTom Butcher Posts: 7,137
    I am pretty sure that the body also tends to burn a higher percentage of fat for a given effort the longer you've been exercising up to about an hour - so if burning a greater proportion of fat was a training aim (and I'm not saying that there is any reason it should be - but some people do aim for that) then one long ride would be better than two medium length rides.

    it's a hard life if you don't weaken.
  • methodmethod Posts: 784
    That was my understanding as well, this was what I received from my coach:

    We call this zone 'RQ1' and it means that at this heart rate and above, you are burning lots of calories but none of them are coming from body fat! Working at these high heart rates are good as you burn a lot of calories and stress your body to promote fitness improvements. However, these calories come from sugar (or carbohydrates) stored in your body and none from deposited body fat! Working at such high intensities should be taken in moderation as you run the risk of injury and illness if you overdo it! Your RQ1 heart rate is 158 bpm and you burn a total of 852 calories/hour.
  • Andy, surely at high intensity (anaerobic effort for example) very little from stores is burnt since the metabolic process is too slow. Of course, once the glycogen store is replenished, could this come from body fat as well as ingested food/blood glucose?

    From experience (dangerous ground here I know) I can ride at a low intensity all day, versus say a max intensity for no longer than 90 minutes. Now is a 6-7 hour touring ride going to use more stored body fat (assuming you dont stuff your face all day whilst on the bike) than a 90 minute alll out TT effort?

    Last season I hardly did any low intensity rides, it was almost all TT's with a couple of high intensity rides in between. I didn't lose any weight between May and October. I lost about half a stone then up to Xmas as I started riding slower but for longer and more frequently. The TT's I rode were a mix of 10's in the week, to a 10 on saturday and a 25 or 50 on sunday. a 100 and an aborted 12 hour were in there too....
  • Tom ButcherTom Butcher Posts: 7,137
    Andy, surely at high intensity (anaerobic effort for example) very little from stores is burnt since the metabolic process is too slow. Of course, once the glycogen store is replenished, could this come from body fat as well as ingested food/blood glucose?
    ...

    I think that glycogen can be converted to fat but not vice versa.

    it's a hard life if you don't weaken.
  • 3wheeler wrote:
    At low intensity you are still burning fat or rather energy you are using is coming from your fat reserves, but you won't be burning many calories, just like me sitting down writing this I'm burning some calories :wink:

    Fat can only provide energy at a fairly slow rate, so when you exceed that your body needs to use the carb supplies, if you increase the intesity you are burning more calories but chances are the amount of fat being used stays the same.

    It's not quite so simple though because you will usually be getting your energy from a combination of sources, however in your 'fat buring zone' a high ratio will be coming from fat.

    What I have read is that at higher intensity you cannot burn fat but carbs/blood sugar. When you rest the body will replace the used carbs by releasing fat stores.
  • Tom ButcherTom Butcher Posts: 7,137
    I'm almost certain that's not the case and that fat stores can not replenish glycogen stores - excess carbs are converted to fat but fat can't be converted to glycogen - as I say though only almost certain.

    it's a hard life if you don't weaken.
  • Tom ButcherTom Butcher Posts: 7,137
    And just to add to that - this is why some people argue the fat burning zone is best for weight loss - as you need to eat to replenish glycogen stores - I've seen some people argue you will actually feel hungry if you don't - whereas you don't need to replenish stored fat as you don't actually want to replenish it if weight loss is a goal. In other words they argue you can better lose weight by fat burning and controlling your diet - if you mainly exercise intensively and limit your diet you will run out of energy.

    it's a hard life if you don't weaken.
  • oldwelshmanoldwelshman Posts: 4,733
    This is getting toooo technical :D Lots of research on net.
    In simple terms, most effective hr for fat burning is 60% max hr.
    That is not to say you will not burn off more fat at 85% effort, you will but at a less efficient rate.
    So if you have plenty of time, spend 4 hours on a ride or exercise at 60% mhr, if you have less time, do 2 hrs TT at 85% and you burn less efficently but more due to the fact your burning more calories.
    Anaerobic is not much use for fat burning, but 85 to 90% is and you will keep burning afterwards also.

    I need to practise this as my gut is currenly too big !!
  • The greater our oxygen transport capacity, the greater we are able to utilise FFA as a fuel source and the greater the rate of utilisation of FFA (v glycogen). Hence training to improve our LT and VO2Max has a direct impact on our ability to use higher proportion of FFA at all (aerobic) exercise intensities.

    IOW - to "burn more fat", we need to train to become aerobically fitter. This is most effectively done at intesities at and around power at LT (~2-3hr power) and up to our power which induces VO2Max (sustainable for ~4-8 minutes).

    To "burn" the most fat over time the equation is very simple - ride at the highest intensity you can sustain for the duration you have available to train. By sustainable I mean not only on that day but also sustainable in the sense that it doesn't substantially impact ability to train on following days or weeks.
  • methodmethod Posts: 784
    Alex,

    Could you clear something up for me, according to the testing I had done, I reached RQ1 at 158bpm and was told that I'm not burning any fat at this point and above. Is that right?

    thanks.
  • method wrote:
    Alex,

    Could you clear something up for me, according to the testing I had done, I reached RQ1 at 158bpm and was told that I'm not burning any fat at this point and above. Is that right?

    thanks.
    Define RQ1
  • If you are referring to Respiratory Quotient, then I would take RQ1 to be ratio of CO2 volume produced to volume O2 utilised being 1:1.

    That being the case then yes, that is when use of FFA as an energy source diminishes substantially and is at or close to 0% and we are fueled primarily by glycogen. It also corresponds to our VO2 being at or near our VO2 Max levels.
  • methodmethod Posts: 784
    Respiratory Quotient 1

    Best explination is here:

    http://en.wikipedia.org/wiki/Respiratory_quotient

    Basically when doing a fitness test, its one of the measurements derived from carbon dioxide production.

    At an RQ of 1 (which I hit at 158bpm) all you are burning are Carbs. Which is surely why the fat burning zone isn't a myth...
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