Does fitness affect metabolic "efficiency"?
Tim Richardson
metabolic efficiency; that is, if a fit person lifts a 10kg weight 3
metres off the ground ten times, he will use less energy than if an
unfit person does it, everything else being the same. Or to be more
practical, if a fit person and an unfit person, of identical sex,
weight, height, age and lean body mass, run a marathon over the same
distance in the same time, the fit person will use less energy. I have
seen some formulas for metabolic rate, and the variables never include
a measure for fitness. Since all humans basically have the same core
blood temperature, I suppose that each gram of muscle has basically
the same efficiency at converting fuel in the blood to work done
(since I suppose the chemical reactions behind this at pretty much the
same in all of us and not really alterable by fitness level).
My friend doesn't accept this argument, on the grounds of common
sense. A fit person must be more efficient, how else can a fit person
run a marathon more easily than an unfit person? He is very fit (does
triathalons) and I am just of average fitness, so our personal
experiences are very different.
Does anyone know the answer?
John the Man
>From: timric...@yahoo.com (Tim Richardson)
>Date: 8/2/03 7:03 PM !!!First Boot!!!
>to be more
>practical, if a fit person and an unfit person, of identical sex,
>weight, height, age and lean body mass, run a marathon over the same
>distance in the same time, the fit person will use less energy.
Ha, ... Hah, Ha!
That is an oxymoron!!!
Depends on the type of fitness. Long distance runners are extremely skinny.
They have a low muscle mass and hence wont burn more calories at rest.
Body builders, however, have a lot more muscle mass and hence they will burn
more calories at rest by virtue of their muscle mass. Muscle burns calories.
Fat does not burn calories. This should be a matter of common sense!!!
Steve Harris
processes. Everybody with a good working gut has about the
same efficiency in converting food calories to HEAT, which
is what you're talking about in keeping warm, and also what
you're talking about in basal metabolic rate. But that's not
the same as the efficiency in converting food calories to
mechanical WORK, when you do work. That runs 20% to 30%
approximately, and depends a good deal on on
fitness/training.
"Tim Richardson" <timric...@yahoo.com> wrote in message
news:62c3a3a6.03080...@posting.google.com...
adrian iles
determined by the amount of work done.
As this is the same for both lifters, the energy used is the same. Their
fitness levels, body types, shoe sizes, etc are irrelevant.
Eddie Iles
bicker 2003
wrote:
> My friend doesn't accept this argument, on the grounds of common
> sense.
Common sense could make the argument either way, in your scenario.
--
¤bicker¤
"It is far better to grasp the Universe as it really is than
to persist in delusion, however satisfying and reassuring."
- Carl Sagan
People are, of course, welcome to place whatever irrelevant
limitations on their ability to enjoy something that they wish.
John the Man
>"Tim Richardson" <timric...@yahoo.com> wrote
>>if a fit person and an unfit person, of identical sex,
>> weight, height, age and lean body mass, run a marathon over the same
>> distance in the same time, the fit person will use less energy.
A few of the replies have lead me to question whether or not the great one
mis-read the original question.
Ha, ... Hah, Ha!
Heck no! This assertion is an oxymoron. You can not ask an illogical question
and then expect a logical answer.
Like most posters on smn, Tim is totally confused as what his question really
is. Ergo, that is his real problem.
And, like so many posts on smn Tim started out with a really great idea but
managed beautifully to put his foot in his mouth before he was finished. :(
The only issue of interest here is resting metabolism levels, *not* energy
expended during a race!!!
Further, the original stupid question could be changed to something logical
like: "if a fit person and an unfit person, of identical sex, weight, height,
age ran a marathon over the same distance; who would use the most energy?"
Then the answer would be *more* than a matter of simple physics.
Both parties weight the same so the fit person would have more muscle than the
unfit person with the most fat. Moving the same amount of weight over the same
distance in the same time would take the same energy. The problem lies in the
fact that the times will never be the same. So, the energy consumption would
never be the same. Going faster takes more energy than going slower. Muscle
would also burn additional calories while Fat does not. Further, the question
of nutrition would come into play. The fit athlete would consume an optimal
diet for running marathons. The unfit person would not even be prepared
nutritionally for the marathon. This would certainly affect expenditure with
an extremely complex equation.
Just my opinion. But, I am *right* as usual!
wuzzy
> My friend doesn't accept this argument, on the grounds of common
> sense. A fit person must be more efficient, how else can a fit person
> run a marathon more easily than an unfit person? He is very fit (does
> triathalons) and I am just of average fitness, so our personal
> experiences are very different.
>
> Does anyone know the answer?
Your friend is correct, the fit person has much more efficiency and
burns *alot* less calories on say a treadmill at the same speed..
Efficency from training is a good thing!
off topic on this
Especially in terms of cardiopulmonary function since the work cost of
breathing is alot higher in obese persons. Ie., obesity causes the
following by mechanical means: 1)diaphragm non-compliance (you and i
move our diaphragms more easily) 2)work cost of moving around. There
is alot of interaction between 1 and 2 and you get panting and screwed
up co2 levels in the blood etc..
anyway one of the benefits of weight loss is more efficient day-to-day
activity.
wuzzy
Also VO2 max and spirometry values change with training without weight
loss wont go into that..
John the Man
>Date: 8/3/03 2:55 PM !!!First Boot!!!
>Your friend is correct, the fit person has much more efficiency and
>burns *alot* less calories on say a treadmill at the same speed..
It is really amazing how many so called scientists have tried to logically
answer an illogical question. :(
You Geeks really are exposing yourselves for the Frauds that you truly are. :)
Just thought that you might want to know. :)
adrian iles
John the Man
>Date: 8/2/03 9:13 PM !!!First Boot!!!
>The energy expended is
>determined by the amount of work done.
>As this is the same for both lifters, the energy used is the same.
Ha, ... Hah, Ha!
The human body ain't no ball rolling on a billiard table, Jack!
The human body burns energy standing still. The amount of energy burt by the
body is determined by a number of factors, including but not limited to muscle
mass.
Moosh:]
<adri...@ntlworld.com> posted:
Yes, the energy in the work actually done will be the same, but the
question is how much food intake will be needed. The same?
Ray Lilley
the efficiency at which a particular activity can be achieved.
There are many systems that have to adapt to any new activity put upon
the body. You can therefore expect an inefficiency, which suggest
unnecessary
work while all the systems adjust and, while trying to maintain it's other
'programmed' physiochemical demands.
I support the view that no matter how 'ready' the body is for a certain
activity, if it is given a new routine it will take effort and time to
'tune' it in, i.e.it will use less energy as the 'whole' adapts.
As for quantifying?
A few years back a young good looking girl looked at me as we passed
each other. A beautiful smile broke on her face as she looked into my eyes.
The rest of my day, even the week, was 'alive'. Everybody got a good side of
me that day. Nothing was too much of an effort. How many got the feel good
factor from me too, I don't know?
So much good energy, ...just a smile.
Regards...
...Ray.
---
Outgoing mail is certified Virus Free. Please wear surgical gloves.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.449 / Virus Database: 251 - Release Date: 27/01/2003