Is heart rate a good measure of fat burning?

Hello, there seems to be little consensus on which exercises burn how
much fat. So, can I just measure the intensity of my calorie burning by
monitoring my heart rate?

Thanks....

Polar heart rate monitors have a calorie counting counter on most of their
models. How accurate they are I don't know. I went for an hour cross-country
run yesterday and burnt around 820 calories according to the monitor.



John

"wizzywiz" wrote in message
oups.com...
Hello, there seems to be little consensus on which exercises burn how
much fat. So, can I just measure the intensity of my calorie burning by
monitoring my heart rate?

Thanks....

wizzywiz wrote:
Hello, there seems to be little consensus on which exercises burn how
much fat. So, can I just measure the intensity of my calorie burning by
monitoring my heart rate?

In a word, no. Even if an HR monitor reports a number of calories
burned, it is a statistical average with a huge(!) margin of error. In
a thread some years ago, one manufacturer offered an estimate of 30-40%
margin of error.

You cannot use HR itself to determine calories burned. However, there
are formulas -- determined by statistical regression (read "for the
typical individual") -- that relate percentage max HR and your max VO2
capacity to calories burned. Of course, the big variable is "your max
VO2". Most of us do not know that, athough there are web sites and
procedures that attempt to help you estimate it. (Again, those
estimate are for "the typical individual", which none of is.)

But any such statistical formula has a large margin of error for any
individual. I also suspect that it has a large margin of error for any
specific mode of exercise.

I recently reposted a formula that I had derived a few years ago based
on other published formulas. It is probably something like what an HRM
uses -- although I have no confirmation of that. Here is my reposting,
in part.

Based on footnote [1]:

kCal = V02max * (%MHR - 37) * 0.000075 * time

VO2max is in ml/min. Time is in minutes. %MHR is the number of
percent, not a fraction. For example, "50" means 50% or 0.50.

Ideally, estimate your VO2max and MHR using any of the fitness tests
for that purpose [8]. Alternatively (with much less accuracy),
estimate your VO2max and MHR with the following formulas. (Note: The
VO2max formulas are my own, derived from published formulas. See
footnote [4].)

male VO2max = (54 - 0.34*age) * weight

female VO2max = (42 - 0.28*age) * weight

MHR = 220 - age, or any other formula or method

Weight is in kg. Weight{kg} = weight{lb} / 2.2.

Footnote 4 has a gender-independent formula for VO2max. However, it
introduces a 10-20% computational "error".

All formulas are based on statistical regressions, so there is an
inherent statistical "error" ("+/- X"). I cannot estimate the standard
error because I do not know the std err for the underlying data. I
suspect that the above is similar to how HRMs compute calories. One
HRM vendor indicates that their estimate is +/- 30-40%(!) [5]. I
expect that is typical.

Example #1:

30-year-old 70-kg male walking 4 MPH at 62% MHR.

(54 - 0.34*30 ml/kg/min) * (70 kg) * (62 - 37 %MHR) *
(0.000075 kCal/ml) * (30 min) = 172 kCal

Example #2:

30-year-old 60-kg female walking 4 MPH at 70% MHR.

(42 - 0.28*30 ml/kg/min) * (60 kg) * (70 - 37 %MHR) *
(0.000075 kCal/ml) * (30 min) = 150 kCal

These example results are similar to results based on the Compendium
[9].


-----
Footnotes

[1] kCal = VO2{ml/min} * kCal/ml * weight{kg} * time{min} [10]

VO2{ml/min} = VO2max{ml/min} * (%V02max / 100)

%V02max = (%MHR - 37) / 0.64 [2]

kCal/ml = 4.8 kCal / 1000 ml [3]

Note that %VO2max and %MHR are the number of percent, not a
fraction. For example, "50" means 50% or 0.50.

[2] Swain (1994)
http://www.brianmac.demon.co.uk/maxhr.htm

[3] http://courses.washington.edu/conj/vo2_2004.htm

[4] My own formula, based on regression analysis of modified Leger [6]
and ACSM estimate of VO2max for "average" male and female [7]. For age
20-60. For age 60+, compute using 60.

Gender-independent formula:

VO2max{ml/min} = (47 - 0.28*age) * weight{kg}

10-12% error for male; 14-20% error for female.

[5] Posting dated Apr 29, 2004 9:24 AM at

http://forums.runnersworld.com/threa...5758&tstart=15


[6] Leger (1982)
http://www.janatrains.com/default.asp?id=19
http://www.brianmac.demon.co.uk/beep.htm

Original Leger, averaged over all ages and both genders, yields a
regression formula similar to Swain, namely:

%V02max = (%MHR - 36) / 0.57

Therefore, I arbitrarily modified Leger to fit the Swain
regression, namely:

%MHR = 45.6 + (0.64 * %VO2max) - 0.41*age + 0.0038*VO2max*age +
1.55*gender

where gender is 1 for male and 2 for female.

[7] ACSM estimate of VO2max, hardcopy, original source unknown.
Provided by the director of a fitness center.

[8] http://www.brianmac.demon.co.uk/vo2max.htm

[9] http://prevention.sph.sc.edu/Tools/C...m_tracking.pdf
[defunct]
http://www.solutionsinfitness.com/kcalexpenditure.htm
http://www.caloriesperhour.com/index_burn.html

[10] http://www.solutionsinfitness.com/kcalexpenditure.htm

wizzywiz wrote:
Hello, there seems to be little consensus on which exercises burn how
much fat. So, can I just measure the intensity of my calorie burning by
monitoring my heart rate?

It's easier than that: 100 calories / mile run, regardless of pace.

Of course that's a first order approximation, subject to some
variation.

- it assumes a runner of about 140 or 150 pounds; if you're
substantially lighter or heavier, scale this by your weight, e.g. 210
pounds = 1.5 * 140 pounds = 1.5 * 100 calories = 150/mile. That's
probably the biggest source of variation and if you take it into
account you're "close enough".

- calories will vary surprisingly little by pace - if you run slower,
you're taking longer to complete the mile and it darn near evens out -
but in the interest of scientific exactitude, it does vary a bit

- terrain (flat vs. mountainous), wind (calm vs. headwind vs.
tailwind), temperature (you'll burn more simply being in the cold),
surface (softer = requires slightly more energy) will all make some
difference

- efficiency: an efficient (several factors here, not necessarily well
understood: experience, biomechanics, pace, shoes, ...) runner requires
less energy than an inefficient one

- as others have noted, you're burning a mix of fat and
carbohydrates... but so what, for weight loss purposes it's probably
just as well to consider that calories are calories

Just figure 100/mile, or 100 * (weight/140 lb), and you won't go too
far wrong.

Pendejo wrote:
100 calories / mile run, regardless of pace.

Of course now that I noticed you crossposted to several groups, I'll
point out the obvious which is that this doesn't help for cycling etc.
It's probably "close enough" for walking though.

"wizzywiz" schreef in bericht
oups.com...
Hello, there seems to be little consensus on which exercises burn how
much fat. So, can I just measure the intensity of my calorie burning by
monitoring my heart rate?

Thanks....


Intensity and calory burning go together like horse and carriage. The lower
the intensity of your activity, the higher the amount of fat that is used as
a source of energy. When the intensity increases the amount of carbon
hydrates increases as a source of energy. The optimun (in this case your
optimum) can't be computed exactly with the use with a hart rate monitor,
but it is generally agreed that at 50-60% of Max you can burn a large amount
of fat.

"wizzywiz" wrote in message
oups.com...
Hello, there seems to be little consensus on which exercises burn how
much fat. So, can I just measure the intensity of my calorie burning by
monitoring my heart rate?

Thanks....

And what makes you think that asking in a range of unrelated forums will
result in a consensus?

"joke" wrote in message
...

"wizzywiz" schreef in bericht
oups.com...
Hello, there seems to be little consensus on which exercises burn how
much fat. So, can I just measure the intensity of my calorie burning
by
monitoring my heart rate?

Thanks....


Intensity and calory burning go together like horse and carriage. The
lower the intensity of your activity, the higher the amount of fat
that is used as a source of energy. When the intensity increases the
amount of carbon hydrates increases as a source of energy. The optimun
(in this case your optimum) can't be computed exactly with the use
with a hart rate monitor, but it is generally agreed that at 50-60% of
Max you can burn a large amount of fat.

Old wives tale, not universally true although it may be true for some
people some of the time.

-S-
http://www.kbnj.com

wizzywiz wrote:
Hello, there seems to be little consensus on which exercises burn how
much fat. So, can I just measure the intensity of my calorie burning by
monitoring my heart rate?

Thanks....

In terms of cycling, the amount of calories burned is directly related
to the amount of work done. In other words power. But this varies
greatly depending upon speed, rider weight, climbs, etc. While there is
a large margin of error, you can estimate power based on HR if you do
some tests first to calibrate yourself. This will be more accurate than
some guess made by the HRM program. Once you figure out what your total
calorie burn is, you can estimate how much is from fat based on the
intensity of your workout, which can be tracked more or less by HR. Fat
burns at all levels of intensity, but is a greater percentage of the
total at lower intensities (though remember the toal is lower too). If
you want maximum fat buring, you want maximum effort. But that is not
practical. If you want maximum fat burning for a minimum of discomfort,
keep the intensity below 70% max HR.

If weight loss is your goal, my personal experience (lost 55lbs) is
that low intensity is key as it allows a large amount of exercise to be
done without leading to ravenous hunger which in turn leads to
overeating and negating all the fat loss that the exercise
accomplished. In other words, I'd rather take 2 steps forward and 0
back that 3 forward and 2 back.

Joseph

"wizzywiz" wrote in message
oups.com...
Hello, there seems to be little consensus on which exercises burn how
much fat. So, can I just measure the intensity of my calorie burning
by
monitoring my heart rate?

There is little consensus for good reason. At the very least, people
adapt to their training programs, which means that how your body fuels a
particular activity will change over time.

For most people, it is best to focus on a specific result, such a losing
weight or a faster 25 mile bicycle time trial, and direct your efforts
towards your goal rather than trying to understand the biochemistry of
fat burning. The "intensity of ... calorie burning" isn't a meaningful
number.

Please state a goal for your exercise program. If your goal is like
that of most people, to "lose fat and tone up", you are best off to
focus your efforts on your diet first and foremost, and pick a form of
exercise or sport you enjoy practicing regularly that does not get you
injured. Changes in performance require close attention to the details
of training; changes in body composition require close attention to the
details of eating.

-S-
http://www.kbnj.com