Calories burned while rowing
Ernie Trish
Various online sources indicate that a vigorous rowing
session will burn about 300-350 calories per 30 minutes
depending on a lot of factors. My understanding is that
these figures are measuring the amount of calories the
muscles use for the workout. Simple enough.
I have also been reading about calories required to help
the body sweat during excersise (example article at:
http://www.infraredsauna.net/medicalinformation.html).
This reference and similar ones indicate each gram of
sweat we produce requires about 0.586 kilo calories.
Since I typically sweat 1.4-1.5 kg (about 3.3 lbs)
during a 45 minute rowing session this would be
820-880 kilo calories.
The question I have is whether to add both the calories
used by the muscles during rowing AND the calories used
to maintain the sweat mechanism in determing how many
total calories I have burned while rowing. Adding the
'sweat calories' more than doubles the calorie figure
and as such has a big impact on the dieting aspects of
the workout.
Regards,
Ernie
Terry Morse
> I have a calorie burn question.
I've been using a Polar 720 heart monitor, which produces a calorie
estimate for each workout. I find it handy, since it gives me an idea of
how much to eat that day.
--
terry morse Palo Alto, CA http://www.terrymorse.com/bike/
Donovan Rebbechi
> I have a calorie burn question.
>
> Various online sources indicate that a vigorous rowing
> session will burn about 300-350 calories per 30 minutes
> depending on a lot of factors. My understanding is that
> these figures are measuring the amount of calories the
> muscles use for the workout. Simple enough.
No. It's not just the amount of calories used by the muscles.
It's the total amount.
Your body operates at about 25% efficiency, so your output would be
about 200 watts.
> The question I have is whether to add both the calories
> used by the muscles during rowing AND the calories used
> to maintain the sweat mechanism in determing how many
> total calories I have burned while rowing. Adding the
No. The 300-350 calories figure is your total energy expense.
Cheers,
--
Donovan Rebbechi
http://pegasus.rutgers.edu/~elflord/
Amit
The total number of calories burned depends on the external work done
and the extra evergy that is used because the human body is not 100%
efficient (25% is a more likely number). The additional energy is
dissipated as heat and I suppose one can correlate that to the amount
one sweats.
The 300-350 cal/30 min figure you quote above sounds like the total
energy used, ie. it accounts for the inefficiency. If you have a way
to measure your workload you could multiply that figure by 4 to get
the total nuber of calories you used.
ex. Typically I might do 1000kJ/hr accorinding to my trainer. If
efficiency is 25%, and there are about 4 kJ in 1 cal. I'm burning 1000
cal/hr.
I could see a rower buring about the same number of calories in an
hour, but not say two times more, which is why I think the figure
above is the approx. total energy used.
-Amit
Justus J.
30 minutes rowing at 180 Watt = 30 * 60 * 180 Joules = 324000 Joules =
77438
Calories = 77.438 kilo Calories
(1 Watt = 1 Joule / Second)
(1 Calorie = 4.184 Joules)
When you take the 25% body efficiency into account, the total amount
of energy used would be 4 * 77.438 kilo Calories = 309.752 kilo
Calories
Justus
--------
erni...@yahoo.com (Ernie Trish) wrote in message news:<7c00d17b.03041...@posting.google.com>...
> I have a calorie burn question.
>
> Various online sources indicate that a vigorous rowing
> session will burn about 300-350 calories per 30 minutes
> depending on a lot of factors. My understanding is that
> these figures are measuring the amount of calories the
> muscles use for the workout. Simple enough.
...
>
> Regards,
> Ernie
Ernie Trish
If I have got this correctly, the body uses energy
like other instruments at less than 100% efficiency.
Not being dissimilar in concept, common units such as
watts and joules are appropriate when discussing body
energy. Like machines, a byproduct of inefficiency is heat
which for its own reasons the body can't have so it
develops the sweat mechanism.
Based on the referenced article
(http://www.infraredsauna.net/medicalinformation.html)
I had made an assumption that the sweat mechanism
itself was an active process (pores dilating or some such)
that had a calorie value associate with it. I am hearing
now that this is true but that it is accounted for in
the commonly sited calorie expenditure numbers for rowing
(300-350 calories per 30 minutes).
Do I have it correct that all the calorie estimates
are not measured directly but derived from assumptions
about wattage, joules, and metabolic efficiency? Is this
how the Polar heart rate monitors estimate calories? I
am guessing not.
erni...@yahoo.com (Ernie Trish) wrote in message news:<7c00d17b.03041...@posting.google.com>...
Phil Holman
"Ernie Trish" <erni...@yahoo.com> wrote in message
news:7c00d17b.03041...@posting.google.com...
> Thanks for the replies,
>
> If I have got this correctly, the body uses energy
> like other instruments at less than 100% efficiency.
> Not being dissimilar in concept, common units such as
> watts and joules are appropriate when discussing body
> energy. Like machines, a byproduct of inefficiency is heat
> which for its own reasons the body can't have so it
> develops the sweat mechanism.
>
> Based on the referenced article
> (http://www.infraredsauna.net/medicalinformation.html)
> I had made an assumption that the sweat mechanism
> itself was an active process (pores dilating or some such)
> that had a calorie value associate with it. I am hearing
> now that this is true but that it is accounted for in
> the commonly sited calorie expenditure numbers for rowing
> (300-350 calories per 30 minutes).
>
>
> Do I have it correct that all the calorie estimates
> are not measured directly but derived from assumptions
> about wattage, joules, and metabolic efficiency?
Yes
>Is this how the Polar heart rate monitors estimate calories? I
> am guessing not.
From heart rate there must be an estimate of power output from a user
programmed set-up value.
From that an integration of varying heartrate (power output) together
with say a 25% efficiency, will come up with an estimate of calories
burned. Likely not very accurate, IMO +/- 10%.
Phil Holman
W K
"Terry Morse" <tmo...@spamcop.net> wrote in message
news:tmorse-FFDBB9....@news.covad.net...
> Ernie Trish wrote:
>
> > I have a calorie burn question.
>
> I've been using a Polar 720 heart monitor, which produces a calorie
> estimate for each workout. I find it handy, since it gives me an idea of
> how much to eat that day.
Most people have bodies equipped with hunger mechanisms that calculate how
much exercise you've done, how many calories are in your food, allowing your
body weight to stay pretty much the same no matter what you do.
If I do say 2 hours my body has done the calculations and cries out until
for more until I have taken in the appropriate amount of calories.
Per Elmsäter
> Most people have bodies equipped with hunger mechanisms that
> calculate how much exercise you've done, how many calories are in
> your food, allowing your body weight to stay pretty much the same no
> matter what you do.
>
That should really be past tense. Most people used to be equipped with this
internal calculator.
--
Perre
Remove and/or replace the DOTs as needed to reply
Harold Buck
"Phil Holman" <phi...@earthlink.not> wrote:
>
> From heart rate there must be an estimate of power output from a user
> programmed set-up value.
> From that an integration of varying heartrate (power output) together
> with say a 25% efficiency, will come up with an estimate of calories
> burned. Likely not very accurate, IMO +/- 10%.
>
You mean when the rowing machine says I burned 831 calories, it might
not be exactly that many?
--Harold Buck
"I used to rock and roll all night,
and party every day.
Then it was every other day. . . ."
-Homer J. Simpson
John Mulholland
John Mulholland
Hexham Rowing Club
"Per Elmsäter" <perDOTe...@teliaDOT.com> wrote in message
news:fojma.6066$Du.2...@newsc.telia.net...
Phil Holman
"Harold Buck" <no_one...@attbi.com> wrote in message
news:no_one_knows-78E9...@netnews.attbi.com...
> In article <NSgma.23187$4P1.2...@newsread2.prod.itd.earthlink.net>,
> "Phil Holman" <phi...@earthlink.not> wrote:
>
> >
> > From heart rate there must be an estimate of power output from a
user
> > programmed set-up value.
> > From that an integration of varying heartrate (power output)
together
> > with say a 25% efficiency, will come up with an estimate of calories
> > burned. Likely not very accurate, IMO +/- 10%.
> >
>
>
> You mean when the rowing machine says I burned 831 calories, it might
> not be exactly that many?
>
> --Harold Buck
What do you think Harold? Does the machine know your efficiency or your
reciprocating mass?
Phil Holman
Ryan Cousineau
"Phil Holman" <phi...@earthlink.not> wrote:
Your "must" about the set-up value is correct, but amusing, because I
have a Cateye CC-HB100 HRM/computer that, while it does provide a
calories-burned estimate, has _no_ user-programmed value.
It's basically a good, functional computer. I've had some problems with
cut-out of the HR, but that may be just because I need to change the
transmitter battery. My other dislikes are: no max HR (but it has
average HR) and it can't save multiple wheel sizes for quick switches
between bikes.
It should be said that the bogo-calorie measurement should still be
useful for comparing the relative amount of work done on different rides.
--
Ryan Cousineau, rcou...@sfu.ca http://www.sfu.ca/~rcousine
President, Fabrizio Mazzoleni Fan Club
Harold Buck
"Phil Holman" <phi...@earthlink.not> wrote:
> "Harold Buck" <no_one...@attbi.com> wrote in message
> news:no_one_knows-78E9...@netnews.attbi.com...
> > In article <NSgma.23187$4P1.2...@newsread2.prod.itd.earthlink.net>,
> > "Phil Holman" <phi...@earthlink.not> wrote:
> >
> > >
> > > From heart rate there must be an estimate of power output from a
> user
> > > programmed set-up value.
> > > From that an integration of varying heartrate (power output)
> together
> > > with say a 25% efficiency, will come up with an estimate of calories
> > > burned. Likely not very accurate, IMO +/- 10%.
> > >
> >
> >
> > You mean when the rowing machine says I burned 831 calories, it might
> > not be exactly that many?
> >
> > --Harold Buck
>
> What do you think Harold? Does the machine know your efficiency or your
> reciprocating mass?
It had better after making me program that info into it.
Phil Holman
> In article <6mlma.23555$4P1.2...@newsread2.prod.itd.earthlink.net>,
> "Phil Holman" <phi...@earthlink.not> wrote:
>
> > "Harold Buck" <no_one...@attbi.com> wrote in message
> > news:no_one_knows-78E9...@netnews.attbi.com...
> > > In article
<NSgma.23187$4P1.2...@newsread2.prod.itd.earthlink.net>,
> > > "Phil Holman" <phi...@earthlink.not> wrote:
> > >
> > > >
> > > > From heart rate there must be an estimate of power output from a
> > user
> > > > programmed set-up value.
> > > > From that an integration of varying heartrate (power output)
> > together
> > > > with say a 25% efficiency, will come up with an estimate of
calories
> > > > burned. Likely not very accurate, IMO +/- 10%.
> > > >
> > >
> > >
> > > You mean when the rowing machine says I burned 831 calories, it
might
> > > not be exactly that many?
> > >
> > > --Harold Buck
> >
> > What do you think Harold? Does the machine know your efficiency or
your
> > reciprocating mass?
>
> It had better after making me program that info into it.
>
> --Harold Buck
So what is your efficiency and how did you measure it?
Phil Holman
MikeF
news:b7cemd$k2a$1...@sparta.btinternet.com...
> Most people have bodies equipped with hunger mechanisms that calculate how
> much exercise you've done, how many calories are in your food, allowing
your
> body weight to stay pretty much the same no matter what you do.
>
> If I do say 2 hours my body has done the calculations and cries out until
> for more until I have taken in the appropriate amount of calories.
Mine just cries out for more calories regardless....
W K
"Per Elmsäter" <perDOTe...@teliaDOT.com> wrote in message
news:fojma.6066$Du.2...@newsc.telia.net...
> > Most people have bodies equipped with hunger mechanisms that
> > calculate how much exercise you've done, how many calories are in
> > your food, allowing your body weight to stay pretty much the same no
> > matter what you do.
> >
>
> That should really be past tense. Most people used to be equipped with
this
> internal calculator.
Ah well, it only ever did work well in one direction. No nagging mechanism
to stop you eating too much as there is for eating too little.
Could you find one person - apart from perhaps Callista Flockhard (sp?) -
where this doesn't work.
Andy Coggan
news:slrnb9glui...@panix2.panix.com...
> In article <7c00d17b.03041...@posting.google.com>, Ernie Trish
wrote:
> > I have a calorie burn question.
> >
> > Various online sources indicate that a vigorous rowing
> > session will burn about 300-350 calories per 30 minutes
> > depending on a lot of factors. My understanding is that
> > these figures are measuring the amount of calories the
> > muscles use for the workout. Simple enough.
>
> No. It's not just the amount of calories used by the muscles.
> It's the total amount.
>
> Your body operates at about 25% efficiency, so your output would be
> about 200 watts.
This is true for cycling, but not necessarily for rowing. In particular, a
significant amount of energy may be wasted by accelerating the body's mass
with each stroke as the seat slides back and forth. The legs must constantly
be accelerated while cycling, but due to intersegmental energy transfer, the
energy required to do so is eventually completely recouped and applied to
the pedals - I don't know if this is also true with respect to the kinetic
energy "invested" in the torso when rowing, but I somewhat doubt it.
Andy Coggan
Andy Coggan
news:6mlma.23555$4P1.2...@newsread2.prod.itd.earthlink.net...
I think Harold's sarcasm would have been more obvious if he'd written
"831.000000000" Calories.
Andy Coggan
Andy Coggan
news:rcousine-BEE99C...@morgoth.sfu.ca...
> > From heart rate there must be an estimate of power output from a user
> > programmed set-up value.
> > From that an integration of varying heartrate (power output) together
> > with say a 25% efficiency, will come up with an estimate of calories
> > burned. Likely not very accurate, IMO +/- 10%.
>
> Your "must" about the set-up value is correct, but amusing, because I
> have a Cateye CC-HB100 HRM/computer that, while it does provide a
> calories-burned estimate, has _no_ user-programmed value.
>
> It's basically a good, functional computer. I've had some problems with
> cut-out of the HR, but that may be just because I need to change the
> transmitter battery. My other dislikes are: no max HR (but it has
> average HR) and it can't save multiple wheel sizes for quick switches
> between bikes.
>
> It should be said that the bogo-calorie measurement should still be
> useful for comparing the relative amount of work done on different rides.
Unless, or course, it is hot...or if you ride at altitude....or if you
didn't sleep well the night before...or if you've been sick recently....or
if you're racing instead of training....or if there's more variability in
your effort during one ride vs. another...or any of the other myriad factors
that influence the HR-power relationship.
Andy Coggan
Stewart Fleming
Andy Coggan wrote:
> I think Harold's sarcasm would have been more obvious if he'd written
> "831.000000000" Calories.
More so if he had written "831.000000005"
STF
Harold Buck
"Phil Holman" <phi...@earthlink.not> wrote:
I measured how much work I did and how many calories I burned doing that
work, and I divided. Simple.
-Harold
James Blythe
> efficiency is 25%, and there are about 4 kJ in 1 cal. I'm burning 1000
> cal/hr.
>
> I could see a rower buring about the same number of calories in an
> hour, but not say two times more, which is why I think the figure
> above is the approx. total energy used.
>
> -Amit
This would seem to fit: 1:57 for an hour is about 1150 calories according to
a Concept 2.
JB.
Harold Buck
Stewart Fleming <stewart...@paradise.net.nz> wrote:
Why? Same number of signifcant figures in each case.
Ernie Trish
I am gathering that with your formula, an accurate
calorie value can be calculated given a watts value since
the other parameters (Joules and Calories) are directly
related to eachother.
Can a manufacturer of an rowing machine (or other excercise
equipment) accurately determine a wattage value? Similarly,
if a rowing machine has accurately reported it has used
an average of 320 watts during a particular session, can
we then accurately derive calories burned?
JustEnM...@Chello.nl (Justus J.) wrote in message news:<6e6ed109.03041...@posting.google.com>...
bones
> if a rowing machine has accurately reported it has used
> an average of 320 watts during a particular session, can
> we then accurately derive calories burned?
>
The rowing machine can measure pretty accurately the useful work done
accelerating the flywheel. This value can be easily converted to calories
or other suitable units. The inaccuracy comes when using this to estimate
actual work done by the rower. It seems that it assumes an efficiency of
about 25 %. All this has been mentioned already.
Does anyone know how accurate this figure is? Does it take into account
both 1) the inefficiency of the body at converting food to mechanical work
*and* 2) work done which doesn't accelerate the flywheel (i'm thinking
mainly mechanical like moving body up and down the slide, non-useful
movements during the drive eg. "bumshoving", elasticity in the handle, etc,
but other losses eg sounds apply too)?
With 1 there will be some individual variation (both genetic and due to
training background), and it will presumably vary with how hard you are
working - in eg a max 2k test you will be using inefficient anaerobic
metabolism much more than during a long steady state ergo. Similarly if the
ambient temperature is high you will be sweating more, which means less
blood going to your muscles and so more reliance on anaerobic mechanisms.
At high altitude less available oxygen again means more anaerobic
metabolism.
2 will vary with things like body weight (more weight to move up the slide)
and technique.
With all these factors, and more, I imagine there can be quite a lot of
variation in actual calories used for the same power readout on the ergo.
Allan Bennett
<URL:mailto:bo...@bones.com> wrote:
> >Similarly,
> > if a rowing machine has accurately reported it has used
> > an average of 320 watts during a particular session, can
> > we then accurately derive calories burned?
> >
>
> The rowing machine can measure pretty accurately the useful work done
> accelerating the flywheel. This value can be easily converted to calories
> or other suitable units. The inaccuracy comes when using this to estimate
> actual work done by the rower. It seems that it assumes an efficiency of
> about 25 %. All this has been mentioned already.
>
> Does anyone know how accurate this figure is? Does it take into account
> both 1) the inefficiency of the body at converting food to mechanical work
> *and* 2) work done which doesn't accelerate the flywheel (i'm thinking
> mainly mechanical like moving body up and down the slide, non-useful
> movements during the drive eg. "bumshoving", elasticity in the handle, etc,
> but other losses eg sounds apply too)?
>
> With 1 there will be some individual variation (both genetic and due to
> training background), and it will presumably vary with how hard you are
> working - in eg a max 2k test you will be using inefficient anaerobic
> metabolism much more than during a long steady state ergo.
There is a bit of over-complication in the thinking, here. Surely, the work
done at the flywheel is just that, no matter how it is produced.
> Similarly if the ambient temperature is high you will be sweating more,
> which means less blood going to your muscles and so more reliance on
> anaerobic mechanisms.
No. Anaerobic energy production is not influenced by oxygen availability,
but by force of contraction.
> At high altitude less available oxygen again means more anaerobic
> metabolism.
Ditto.
>
> 2 will vary with things like body weight (more weight to move up the slide)
> and technique.
>
> With all these factors, and more, I imagine there can be quite a lot of
> variation in actual calories used for the same power readout on the ergo.
But there are no prizes for those who waste the most energy, or for those who
perform the most efficiently...
Allan Bennett
--
Neil Wallace
>
> I am gathering that with your formula, an accurate
> calorie value can be calculated given a watts value since
> the other parameters (Joules and Calories) are directly
> related to eachother.
>
> Can a manufacturer of an rowing machine (or other excercise
> equipment) accurately determine a wattage value? Similarly,
> if a rowing machine has accurately reported it has used
> an average of 320 watts during a particular session, can
> we then accurately derive calories burned?
>
To put a different slant on this, ask this question...
If I drive my car at 74,570W (100hp) for an hour.. how much fuel will I have
used?
Take my point? even with a mechanical system, a fuel with a very consistent
digestion mechanism and known calorific value, it is still a pretty vague
situation.
The efficiency of the engine is probably what matters most, and we know
there is a massive variation in this... I would guess humans vary even
more.. even before you add BMR considerations, but 25% seems consensus
opinion for the rowing action.
Does it really matter to get anything more than a rough idea of calories
anyway?
I would suggest if it does, then you have a very good post-grad sports
science project, measuring internal body temp, weight loss during workout,
calorie intake, residual calorific value of stools, etc., etc., etc.
Terry Morse
> Ah well, it only ever did work well in one direction. No nagging mechanism
> to stop you eating too much as there is for eating too little.
> Could you find one person - apart from perhaps Callista Flockhard (sp?) -
> where this doesn't work.
My hungry/full indicators aren't very accurate, so I have to eat before
I'm hungry and keep eating after I'm full. It must be genetic, since
siblings have the same "problem".
--
terry morse Palo Alto, CA http://www.terrymorse.com/bike/
bones
work
> done at the flywheel is just that, no matter how it is produced.
I'm aware of that, my point was there are plenty of ways energy can be lost
between it being stored in food and moving of the flywheel, which will
differ for different people, and under different conditions. Maybe I didn't
explain it very well.
> > Similarly if the ambient temperature is high you will be sweating more,
> > which means less blood going to your muscles and so more reliance on
> > anaerobic mechanisms.
>
> No. Anaerobic energy production is not influenced by oxygen availability,
> but by force of contraction.
That's interesting. Is there an explanation? Since even type I muscle
fibres have at least limited anaerobic ie. glycolytic capacity (as well as
aerobic capacity), and type IIa fibres certainly do, I'd would have expected
flux through these pathways to increase when oxidative ATP production falls
due to oxygen limitation, to make up for a bit of the shortfall.
If this isn't the case, erging in a hot room will still decrease your
"efficiency" through the increased cardiac output (and so HR) required to
pump enough blood to go to the skin for sweating, and to supply the muscles
for contraction.
>
> But there are no prizes for those who waste the most energy, or for those
who
> perform the most efficiently...
>
Sure (although efficiency is obviously an advantage), but the original
question was about whether the calorie readout on the monitor is accurate.
Ernie Trish
"Neil Wallace" <rowing...@NOSPAM.virgin.net> wrote in message news:<b7hcj0$2l$1...@hercules.btinternet.com>...
Now whose the one getting anal about calories?
Phil Holman
And that completes the circle. Way to go Harold :-)
Phil Holman
W K
> W K wrote:
>
> > Ah well, it only ever did work well in one direction. No nagging
mechanism
> > to stop you eating too much as there is for eating too little.
> > Could you find one person - apart from perhaps Callista Flockhard
(sp?) -
> > where this doesn't work.
>
> My hungry/full indicators aren't very accurate, so I have to eat before
> I'm hungry and keep eating after I'm full. It must be genetic, since
> siblings have the same "problem".
Are you really thin then?
Can I have the patent rights to your genes?
Allan Bennett
<URL:mailto:bo...@bones.com> wrote:
> > There is a bit of over-complication in the thinking, here. Surely, the
> > work done at the flywheel is just that, no matter how it is produced.
>
> I'm aware of that, my point was there are plenty of ways energy can be lost
> between it being stored in food and moving of the flywheel, which will
> differ for different people, and under different conditions. Maybe I
> didn't explain it very well.
Your explanation was OK, maybe it's just me...
Perhaps, I am finding the arguments a bit specious and futile, esp as you
seem to be stating that energy is being lost, thus dispelling one of the most
enduring paradigms in science.
>
> > > Similarly if the ambient temperature is high you will be sweating more,
> > > which means less blood going to your muscles and so more reliance on
> > > anaerobic mechanisms.
> >
> > No. Anaerobic energy production is not influenced by oxygen
> > availability, but by force of contraction.
>
> That's interesting. Is there an explanation?
An explanation of why nature is the way it is or why sports 'scientists' and
athletics comics doggedly give an alternative but inaccurate view?
> Since even type I muscle fibres have at least limited anaerobic ie.
> glycolytic capacity (as well as aerobic capacity),
By definition, this is contradictory, I'm afraid - glycolysis is the
breakdown of glucose. Glycogen, despite being a glucose polymer, does not
get converted to glucose when it is metabolise anaerobically.
Only white muscle will use the energy released from anaerobic breakdown of
glycogen for muscle contraction, and it does this when there is a requirement
for high force contraction, not when there is a shortage of oxygen.
> and type IIa fibres certainly do, I'd would have expected flux through
> these pathways to increase when oxidative ATP production falls due to
> oxygen limitation, to make up for a bit of the shortfall.
You might expect it, but if an actively contracting muscle is starved of
oxygen, it slows down, it does not go anaerobic. White fibres are under
separate and distinct neuronal control.
>
> If this isn't the case, erging in a hot room will still decrease your
> "efficiency" through the increased cardiac output (and so HR) required to
> pump enough blood to go to the skin for sweating, and to supply the muscles
> for contraction.
If there is a resultant decrease in oxygen supply to the active muscles, a
concomitant decrease in performance could be anticipated (along with other
reasons, of course).
However, there is little evidence that oxygen supply is a limiting factor,
and the necessity for sweating and skin vasodilation is to maintain the
working muscles and blood at the temperature at which the enzymes responsible
for muscle contraction remain at their most efficient...
> >
> > But there are no prizes for those who waste the most energy, or for those
> who
> > perform the most efficiently...
> >
>
> Sure (although efficiency is obviously an advantage), but the original
> question was about whether the calorie readout on the monitor is accurate.
Improved efficiency is only an advantage if it is the limiting factor. In
most active sports, it is the athlete who gets to the line first who wins,
whether they are performing efficiently or not (mechanically or
biochemically). And, no, the readout will not be accurate - especially if
you expect it to take into account all other uses of fuels, nervous stress
and variations in metabolic rates etc.
Allan Bennett
--
bones
> seem to be stating that energy is being lost, thus dispelling one of the
most
> enduring paradigms in science.
OK! But you know what I meant was that not all the energy stored in food
ends up doing useful work at the flywheel. The rest of my post was gave
examples of possible ways efficiency might vary, both due to individual
difference and outside factors. It may be that these have a relatively
insignificant effect on efficiency, I don't know. And admittedly my
suggestions about ambient temperature and altitude were rather far fetched
and not based on evidence, just my limited understanding of physiology /
biochemistry.
> > > No. Anaerobic energy production is not influenced by oxygen
> > > availability, but by force of contraction.
> >
> > That's interesting. Is there an explanation?
>
> An explanation of why nature is the way it is or why sports 'scientists'
and
> athletics comics doggedly give an alternative but inaccurate view?
An explanation for why oxygen availability doesn't influence anaerobic
metabolism, which you go on to give. But if I could take you up on a couple
of points, just to satisfy my curiosity:
> > Since even type I muscle fibres have at least limited anaerobic ie.
> > glycolytic capacity (as well as aerobic capacity),
>
> By definition, this is contradictory, I'm afraid - glycolysis is the
> breakdown of glucose. Glycogen, despite being a glucose polymer, does not
> get converted to glucose when it is metabolise anaerobically.
True, my terminology was wrong. But the G6P produced by glycogen breakdown
must go through the glycolytic pathway, during which some ATP is generated
non-oxidatively, for NADH to be produced (including in the TCA cycle) for
oxidative phosphorylation. But am happy to accept this may not be
significant.
> Only white muscle will use the energy released from anaerobic breakdown of
> glycogen for muscle contraction, and it does this when there is a
requirement
> for high force contraction, not when there is a shortage of oxygen.
>if an actively contracting muscle is starved of
> oxygen, it slows down, it does not go anaerobic. White fibres are under
> separate and distinct neuronal control.
From these 2 points I might conclude that if the oxygen supply to my muscles
falls (for whatever reason) during a long aerobic ergo, when I am mainly
using type I fibres, then I will simply become unable to maintain the same
power output. Of course I've never tried this, but I find it rather hard to
believe - surely if my aerobic fibres are producing slightly less force, I
can just recruit some more anaerobic (type IIa? - I know classifications
have changed now) ones to make up the shortfall for a little while? After
all, I must be using a few anaerobic fibres during my aerobic ergo, as if
suddenly upped the rating to 34 but kept on pulling as hard (or as gently)
I'd soon start to feel the lactate. So it must be possible to recruit some
anaerobic fibres at the force levels generated in the stroke. Obviously if
this means I am producing more lactate than my liver can remove then sooner
or later I'll have to stop. But in the meantime I think I should be able to
maintain the same power output. Can you tell me where I am wrong?
> > If this isn't the case, erging in a hot room will still decrease your
> > "efficiency" through the increased cardiac output (and so HR) required
to
> > pump enough blood to go to the skin for sweating, and to supply the
muscles
> > for contraction.
>
> If there is a resultant decrease in oxygen supply to the active muscles, a
> concomitant decrease in performance could be anticipated (along with other
> reasons, of course).
>
> However, there is little evidence that oxygen supply is a limiting factor,
> and the necessity for sweating and skin vasodilation is to maintain the
> working muscles and blood at the temperature at which the enzymes
responsible
> for muscle contraction remain at their most efficient...
I guess what I mean to say is that under the conditions I mentioned, ie.
high ambient temperature or low atmospheric pO2, efficiency will fall
because either oxygen supply to muscles will be reduced (which you have
stated is not a limiting factor), or because more energy will be used by the
heart to increase cardiac output in order that oxygen supply to the muscles
is maintained.
> Improved efficiency is only an advantage if it is the limiting factor. In
> most active sports, it is the athlete who gets to the line first who wins,
> whether they are performing efficiently or not (mechanically or
> biochemically).
Technical and physiological efficiency is always a limiting factor to one's
own performance (which is important to some people), but not always to
whether you come first or last.
terry morse
> "Terry Morse" <tmo...@spamcop.net> wrote
> >
> > My hungry/full indicators aren't very accurate, so I have to eat before
> > I'm hungry and keep eating after I'm full. It must be genetic, since
> > siblings have the same "problem".
>
> Are you really thin then?
5' 11", 135 lbs. Most people would consider that thin. It certainly
makes climbing easier.
> Can I have the patent rights to your genes?
:-)
Øyvind Røtvold
> "Terry Morse" <tmo...@spamcop.net> wrote in message
> news:tmorse-FFDBB9....@news.covad.net...
> > Ernie Trish wrote:
> >
> > > I have a calorie burn question.
> >
> > I've been using a Polar 720 heart monitor, which produces a calorie
> > estimate for each workout. I find it handy, since it gives me an idea of
> > how much to eat that day.
>
> Most people have bodies equipped with hunger mechanisms that calculate how
> much exercise you've done, how many calories are in your food, allowing your
> body weight to stay pretty much the same no matter what you do.
Most people also have bodies equipped with fatigue mecanisms that will
tell them when their heart rate is to high, yet we still find that we
need heart rate monitors; these mechanisms simply don't work to
perfection..
>
> If I do say 2 hours my body has done the calculations and cries out until
> for more until I have taken in the appropriate amount of calories.
>
>
--
__o | Řyvind Rřtvold
_`\(, | http://www.darkside.no/olr/index.html
(_)/(_) | ... biciclare necesse est ...
Andy Coggan
news:87llxx9...@net2b.kongsberg.com...
> "W K" <hyag...@tesco.net> writes:
>
> > "Terry Morse" <tmo...@spamcop.net> wrote in message
> > news:tmorse-FFDBB9....@news.covad.net...
> > > Ernie Trish wrote:
> > >
> > > > I have a calorie burn question.
> > >
> > > I've been using a Polar 720 heart monitor, which produces a calorie
> > > estimate for each workout. I find it handy, since it gives me an idea
of
> > > how much to eat that day.
> >
> > Most people have bodies equipped with hunger mechanisms that calculate
how
> > much exercise you've done, how many calories are in your food, allowing
your
> > body weight to stay pretty much the same no matter what you do.
>
> Most people also have bodies equipped with fatigue mecanisms that will
> tell them when their heart rate is to high, yet we still find that we
> need heart rate monitors; these mechanisms simply don't work to
> perfection..
"These mechanisms" actually work better than heart rate monitors (read the
abstracts for the upcoming American College of Sports Medicine meeting).
Andy Coggan
Allan Bennett
<URL:mailto:o...@iname.com> wrote:
> "W K" <hyag...@tesco.net> writes:
>
> > "Terry Morse" <tmo...@spamcop.net> wrote in message
> > news:tmorse-FFDBB9....@news.covad.net...
> > > Ernie Trish wrote:
> > >
> > > > I have a calorie burn question.
> > >
> > > I've been using a Polar 720 heart monitor, which produces a calorie
> > > estimate for each workout. I find it handy, since it gives me an idea
> > > of how much to eat that day.
> >
> > Most people have bodies equipped with hunger mechanisms that calculate
> > how much exercise you've done, how many calories are in your food,
> > allowing your body weight to stay pretty much the same no matter what you
> > do.
>
> Most people also have bodies equipped with fatigue mecanisms that will tell
> heart rate monitors; these mechanisms simply don't work to perfection..
Who is this "we" that "need heart rate monitors"? Having used them for a
couple of decades or so with athletes of various standards, I find them a
distraction and relatively useless as a coaching tool...
Allan Bennett
--
Tom Kunich
lower levels. Heart rate monitors aren't necessary for those hard days
though it can give information on whether you are beginning to
overtrain. They are most useful in showing you that you are working to
hard on your easy days.
"Andy Coggan" <aco...@earthlink.net> wrote in message
news:Q%xqa.41575$ey1.3...@newsread1.prod.itd.earthlink.net...
Tom Kunich
news:ant26173...@freeserve.co.uk...
>
> Who is this "we" that "need heart rate monitors"? Having used them
for a
> couple of decades or so with athletes of various standards, I find
them a
> distraction and relatively useless as a coaching tool...
I agree with this on the proviso that they are necessary to develop
the "feel" for the right training levels. After you know how to train
you don't need heart rate monitors and you should also drop bike
computers as well. That is also a distraction that leads to you trying
to go too hard on easy days.
Raptor
> "Řyvind Rřtvold" <o...@iname.com> wrote in message
> news:87llxx9...@net2b.kongsberg.com...
>>
>>tell them when their heart rate is to high, yet we still find that we
>>need heart rate monitors; these mechanisms simply don't work to
>>perfection..
>
>
> "These mechanisms" actually work better than heart rate monitors (read the
> abstracts for the upcoming American College of Sports Medicine meeting).
>
> Andy Coggan
During a very difficult interval session last Wednesday, I felt a new
pressure/pain in my chest. It went away after I immediately backed off
on the effort.
Is this the kind of mechanism you have in mind or was there another that
I should have listened to first? (I apologize if this is over the line
of asking for medical advice on the net.)
--
--
Lynn Wallace http://www.xmission.com/~lawall
"Let me tell you what else I'm worried about. I'm worried about an
opponent who uses nation building and the military in the same
sentence. See, our view of the military is for the military to be
properly prepared to fight and win war and therefore, prevent war from
happening in the first place." George Bush, Nov. 6, 2000
Andy Coggan
> Andy Coggan wrote:
> > "Řyvind Rřtvold" <o...@iname.com> wrote in message
> > news:87llxx9...@net2b.kongsberg.com...
> >>
> >>Most people also have bodies equipped with fatigue mecanisms that will
> >>tell them when their heart rate is to high, yet we still find that we
> >>need heart rate monitors; these mechanisms simply don't work to
> >>perfection..
> >
> >
> > "These mechanisms" actually work better than heart rate monitors (read
the
> > abstracts for the upcoming American College of Sports Medicine meeting).
> >
> > Andy Coggan
>
> During a very difficult interval session last Wednesday, I felt a new
> pressure/pain in my chest. It went away after I immediately backed off
> on the effort.
>
> Is this the kind of mechanism you have in mind or was there another that
> I should have listened to first? (I apologize if this is over the line
> of asking for medical advice on the net.)
Not the kind of mechanism I had in mind, and definitely not normal - you
should follow up with a cardiologist.
Andy Coggan
Raptor
If I had insurance, I would. As it is, a web search indicates that the
pain I felt was not all that unusual. I believe (hope) that I did
nothing more than temporarily fail to meet my heart's oxygen needs. It
was a REAL hard session, and I was pushing my hardest at the time.
{AGUT2}=IWIK=
> pain I felt was not all that unusual. I believe (hope) that I did
> nothing more than temporarily fail to meet my heart's oxygen needs. It
> was a REAL hard session, and I was pushing my hardest at the time.
Probably worth at least getting the old cholesterol checked. It *might*
make you reasses what you can / can't afford :)
Alex.
--
Reply to:alexan.tili...@ambtinternet.com cutting out the usual...
For all your UT2003 questions, visit the official UT2003 newsgroup FAQ at:
http://www.unrealtower.org/faq.php
Harold Buck
>
> If I had insurance, I would. As it is, a web search indicates that the
> pain I felt was not all that unusual. I believe (hope) that I did
> nothing more than temporarily fail to meet my heart's oxygen needs. It
> was a REAL hard session, and I was pushing my hardest at the time.
>
Mark Twain said, "Be careful about reading health books. You could die
of a misprint."
The same goes a hundredfold for the internet.
Raptor
>> If I had insurance, I would. As it is, a web search indicates that
>> the pain I felt was not all that unusual. I believe (hope) that I did
>> nothing more than temporarily fail to meet my heart's oxygen needs.
>> It was a REAL hard session, and I was pushing my hardest at the time.
>
>
> Probably worth at least getting the old cholesterol checked. It *might*
> make you reasses what you can / can't afford :)
>
> Alex.
Last I checked, a few years ago, it was just shy of "high." If I drop
off the net completely in the near future, at least you all know why
now. :-)
I feel pretty safe. I don't know if I've EVER worked my body/heart as
hard as I did last week when this happened. I don't need to be pushing
my max that much, having achieved an acceptable level of fitness.
But perhaps I'll go to the local sports science academy and have a
maximal heart rate test done. That's pretty cheap.
Raptor
> In article <3EAC74C7...@attbi.com>, Raptor <m...@attbi.com> wrote:
>
>
>>If I had insurance, I would. As it is, a web search indicates that the
>>pain I felt was not all that unusual. I believe (hope) that I did
>>nothing more than temporarily fail to meet my heart's oxygen needs. It
>>was a REAL hard session, and I was pushing my hardest at the time.
>>
>
>
>
> Mark Twain said, "Be careful about reading health books. You could die
> of a misprint."
>
> The same goes a hundredfold for the internet.
>
> --Harold Buck
I'll have to re-read some of them, but they looked like reputable
sources. I know I'm not supposed to be doing my own diagnosing from
reading stuff, but there are choices one must make in this job market.
John Ionides
on point (2). I am sure we have all sat next to a non-rower in the gym
who is pegging up and down the slide and is absolutely knackered while
only pulling 3:00 splits. The erg simply has know way of knowing this
and the calorie readout is unlikely to be correct in this case [to put
it mildly]. It is hard to imagine that the rest of us do not lie
somewhere on a scale including this non-rower and some theorectially
optimal stroke profile, all with differing efficiencies.
As far as metabolic efficiency is concerned, I would have to check
this but I imagine that, for instance, the percentage fat being used
would have an effect on efficiency [i.e. it is unlikely that all
catabolic processes have exactly the same efficiency] although, as
ever, how significant such an effect is might take a little work to
estimate. Also, if we end up estimating a range between 24.5% and
25.5% then we could reasonably say that we don't care. If we end up
talking about a range between 20% and 30% then the errors become very
significant.
Personally, I never use the energy expenditures measured by ergs
because I simply don't belive the numbers (or, more precisely, I don't
think that they measure anything that I can't derive from steady state
split times.)
And, of course, as I am sure you worked out yourself the law of
conservation of energy holds (shock! horror! no need to rewrite the
physics books ...) - if the efficiency is lower then the total energy
expenditure is merely higher to get the same work on the flywheel -
otherwise stated as that fact that I, an unfit part-time rower could
hold down a 3:00 split using far less total energy expenditure than my
non-rowing mates at the gym (except the ones I have coached, that is,
who have nigh-on perfect technique :) )
J
Øyvind Røtvold
> In article <87llxx9...@net2b.kongsberg.com>, Ųyvind_Rųtvold
> <URL:mailto:o...@iname.com> wrote:
> > "W K" <hyag...@tesco.net> writes:
> >
> > > "Terry Morse" <tmo...@spamcop.net> wrote in message
> > > news:tmorse-FFDBB9....@news.covad.net...
> > > > Ernie Trish wrote:
> > > >
> > > > > I have a calorie burn question.
> > > >
> > > > I've been using a Polar 720 heart monitor, which produces a calorie
> > > > estimate for each workout. I find it handy, since it gives me an idea
> > > > of how much to eat that day.
> > >
> > > Most people have bodies equipped with hunger mechanisms that calculate
> > > how much exercise you've done, how many calories are in your food,
> > > allowing your body weight to stay pretty much the same no matter what you
> > > do.
> >
> > Most people also have bodies equipped with fatigue mecanisms that will tell
> > them when their heart rate is too high, yet we still find that we need
> > heart rate monitors; these mechanisms simply don't work to perfection..
>
> Who is this "we" that "need heart rate monitors"?
It is me, some of the cyclists I know who use them, some of the
non-cyclist that I know who don't use them, most of the pros, but
obviously not you - I think that all of us can live and ride happily
with this situation.
> Having used them for a
> couple of decades or so with athletes of various standards, I find them a
^^^^^^^^^^^^^^^^^
You must be very patient.
> distraction and relatively useless as a coaching tool...
--
__o | Ųyvind Rųtvold
J
Firstly on the burning of Calories issue, something very similar which we did as a
class example in kinetics was the study of uptake of alcohol into the system and
the breaking down of the complex it forms once in the system. As far as the
exsample went, it stated that the rates at which the breaking down of the alcohol
was not dependent on the concentration and (more importantly) that this rate was
generally fixed. I know this is a bit of a wild fly but gut feel says that a
similar equation should apply to the burning of energy. The trick would be in
discerning whether or not the energy being consumed is fat etc. Which once again
comes down to the computer not know what type of energy is being burned and at what
rate. So yes that value probably can't be trusted. But then again for that matter
the value which your bathroom scale gives you probably can't be believed either,
but we still use it. So in the end I think that if you want to use calories burnt
during the session as an indicator of effort put in during the session then it
should be used as a relative value. To come back to the original thread which asked
if you should use this value to balance the food books then for example 200 kcal
burned means you need to put in 400 kcal etc. This would probably have some form of
experimental set-up to see if you feel replenished after eating x amount of kcal
after burning y kcal...
Secondly, the issue of heart rate monitors boils down to exactly the same thing. It
is all a relative thing. Each body has it's own mechanisms and to say that a whole
boat should train at 200 bpm or even 80% of max. is a very hap hazard way of doing
it. Unfortunately until science has come up with a fool proof way of getting people
fit, the heart rate monitor will never be fully utilized as a means for getting
people to the best possible level of fitness. Instead people will go on this
"thing" which a lot of people go for, this "that's how such and such train so we
should do the same". Which mostly works but never quite gives the same results...
Regards
J
Řyvind Rřtvold wrote:
> Allan Bennett <albe...@eclipse2k.freeserve.co.uk> writes:
>
> > In article <87llxx9...@net2b.kongsberg.com>, Řyvind_Rřtvold
> __o | Řyvind Rřtvold
John Ionides
> a class example in kinetics was the study of uptake of alcohol into the system
> and the breaking down of the complex it forms once in the system. As far as the
> was not dependent on the concentration and (more importantly) that this rate was
> generally fixed. I know this is a bit of a wild fly but gut feel says that a
> similar equation should apply to the burning of energy. The trick would be in
> discerning whether or not the energy being consumed is fat etc.
I think that you might find that the metabolism of achohol (ethanol)
is something of a special case in this regard, essentialy limited by a
single reaction (the dissociation of the achohol dehydrogenase complex
with NADH) which is realtively easily saturated (e.g. by a couple of
glasses of wine). Sugar and fat metabolism are somewhat more complex
[mild understatement], each with numberous points of control / rate
limiting steps and are unlikely to exhibit the same simple behaviour.