Australia and New Zealand · Public discussion

Re: Polar Heart rate monitor help

Started by Gags · · Last activity · 2 posts · 541 views

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Australia and New Zealand
Published
2 April 2004
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2 April 2004
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Gags
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  1. "DRS" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    Gags <[email hidden]> wrote in message
    [email hidden]

    [...]

    Quoted message said:

    I generally use the HRM to train within a certain HR zone, depending
    on what I am trying to achieve with the session (ie. fat burning,
    cardiac base, intervals, lactic tolerance). It is actually pretty
    hard to keep the HR low enough to stay in the fat burning zone
    (generally I work on 60%-70% of max HR) and so keeping it down to
    about 120bpm makes me feel like I am bludging.

    The idea of the 'fat burning zone' is a myth. It's based on poor
    understanding of both physiology and maths. Your body's prime sources of
    energy are carbohydrates and fat.

    For one refering to "poor understanding of both physiology and maths", this
    is very simplistic.....the body actually has 3 energy systems....Phosphate,
    Lactate, and Aerobic. The fuel for these systems are respectively: creatine
    phosphate, glucose (from carbs), fat and carbs. All three of these energy
    systems use adenosine triphosphate (or ATP) as the final fuel that provides
    energy for the contraction of muscles. These three systems overlap to some
    degree as intensity and duration varies but basically you want to train at
    an intensity that utilises the aerobic ("with air"😉 energy system in order
    to oxidise fat. And before you acuse me....this stuff is coming out of the
    grey matter, not from some text book that I have read once.

    Quoted message said:

    Now, it is true that your body derives a
    higher proportion of its energy from carbohydrate the harder you train.


    For

    Quoted message said:

    every 10 calories you burn during exercise at a high intensity (85%


    VO2max),

    Quoted message said:

    up to 3 of those calories will come from fat. For every 10 calories you
    burn during exercise at a moderate intensity (65% VO2max), up to 6 of


    those

    Quoted message said:

    calories will come from fat. This is the source of the concept but it has


    a

    Quoted message said:

    fatal flaw. When you do the maths you actually expend more calories from
    fat at high intensity work levels.

    Consider the fat calories expended by a 130-pound woman during cardio
    exercise [1]:

    MI (60-65% MHR) HI (80-85% MHR)
    Total Calories Expended per min. 4.86 6.86
    Fat Calories expended per min. 2.43 2.7
    Total Calories expended in 30 min. 146 206
    Total Fat calories expended in 30 min. 73 82
    Percentage of fat calories burned 50% 39.85%

    The point is that although the MI workout expended a higher proportion of
    calories from fat, the high intensity workout expended more calories from
    fat in absolute terms and it's the absolute numbers which matter in this
    context. Assuming the same calory intake, the woman in question would


    lose

    Quoted message said:

    fat faster doing the high intensity workout even though it's nominally
    outsided her 'fat burning zone'. As a bonus, the high intensity exercise
    will increase her Basal Metabolic Rate (BMR) more than the moderate
    intensity exercise, so she will burn more calories per day anyway.

    In short, if you want to burn more fat then work harder for longer.

    Your argument is fine for a half hour workout but I generally work on a one
    hour minimum for a "fat burning" workout and often extend the work out for
    two to three hours. This is not achievable at a high intensity for three
    hours (at least not if you want to do 4-5 workouts a week).

    Quoted message said:

    [1] The 24/5 Complete Personal Training Manual, 24 Hour Fitness, 2000

    --

    A: Top-posters.
    Q: What is the most annoying thing on Usenet?

  2. Gags <[email hidden]> wrote in message
    [email hidden]

    Quoted message said:

    "DRS" <[email hidden]> wrote in message
    news:[email hidden]...

    [...]

    Quoted message said:
    Quoted message said:

    The idea of the 'fat burning zone' is a myth. It's based on poor
    understanding of both physiology and maths. Your body's prime
    sources of energy are carbohydrates and fat.

    For one refering to "poor understanding of both physiology and
    maths", this is very simplistic.....the body actually has 3 energy
    systems....Phosphate, Lactate, and Aerobic. The fuel for these
    systems are respectively: creatine phosphate, glucose (from carbs),
    fat and carbs. All three of these energy systems use adenosine
    triphosphate (or ATP) as the final fuel that provides energy for the
    contraction of muscles. These three systems overlap to some degree
    as intensity and duration varies but basically you want to train at
    an intensity that utilises the aerobic ("with air"😉 energy system in
    order to oxidise fat.

    Yes, it is simplistic, but at least it's not misleading. Firstly, creatine
    phosphate is not a *prime* source of energy and it's anaerobic, producing
    short, very intense bursts of energy (a few seconds) useful for things like
    weightlifting (which is why I've got a tub of creatine on my shelf),
    jumping, throwing and short sprints, and as such completely irrelevant to
    any discussion about "fat burning zones". Secondly, carbohydrates are not
    the only possible source of glucose (it can also be derived from fats and
    proteins), and since you want to get picky then it is more accurate in this
    context to refer to muscle glycogen (glucose stored in the muscles) rather
    than glucose anyway if you want to start bringing ATP cycles into this.
    Thirdly, the distinction you make between glucose and the complex
    carbohydrates which will be ultimately broken down for their glucose is
    misleading in an endurance context since muscle glycogen is depleted in a
    matter of minutes and therefore the bulk of the glucose expended during an
    extended ride comes from ongoing glycolysis (carbohydrates -> glucose) and
    lipolysis (fats -> glucose) anyway.

    Quoted message said:

    And before you acuse me....this stuff is
    coming out of the grey matter, not from some text book that I have
    read once.

    What's that supposed to mean? Are you suggesting you know more than the
    sports doctors?

    [...]

    Quoted message said:
    Quoted message said:

    The point is that although the MI workout expended a higher
    proportion of calories from fat, the high intensity workout expended
    more calories from fat in absolute terms and it's the absolute
    numbers which matter in this context. Assuming the same calory
    intake, the woman in question would lose fat faster doing the high
    intensity workout even though it's nominally outsided her 'fat
    burning zone'. As a bonus, the high intensity exercise will
    increase her Basal Metabolic Rate (BMR) more than the moderate
    intensity exercise, so she will burn more calories per day anyway.

    In short, if you want to burn more fat then work harder for longer.

    Your argument is fine for a half hour workout but I generally work on
    a one hour minimum for a "fat burning" workout and often extend the
    work out for two to three hours. This is not achievable at a high
    intensity for three hours (at least not if you want to do 4-5
    workouts a week).

    Who says you can only do high intensity for half an hour? And why would you
    want to extend your fat burning exercise to three hours when you can achieve
    at least the same result and demonstrably more in less time?

    --

    Quidquid latine dictum sit, altum videtur.

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