Calories burned while rowing

Quoted message said:

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.

Some of points to consider:

1. The website you are looking at is a website selling Infra-red sauna's as a method of
weight-loss. Not exactly a trust worthy site.

2. Consider the mechanism of sweating and how it cools you. The body only puts water on the surface
of the skin, it does not vaporize it. Putting water on the surface of the skin does not actually
consume much energy. It is only when that water is evaporated by the air that heat is transferred
from the body to the air and thus the body is cooled.

Now in a Sauna, that heat is coming from the Sauna rather than from exercise so the body does not
actually have to provide any energy in order to vaporize that water, it is simply getting to hot
because the Sauna is adding calories in the form of radiant heat to the body.

So while evaporating sweat does require calories, those calories do not necessarily need to be food
calories and in the case of the sauna, they would seem to come from the sauna rather than the
persons metabolic processes.

3. The body is about 25% efficient in converting food energy (calories) into mechanical energy. The
other 75% is heat and sweating cools you off.

If you want to do this exactly, you need to measure these things exactly and that includes measuring
your actual energy expendature rather than just estimating it.

Your question is sort of like asking if one needs to include the heat lost through the radiator when
computing the fuel mileage of the car. The answer is that the heat lost through the radiator is
accounted for via the efficiency of the engine.

So when they suggest that you burn 350 x 45min/30 min = 525 calories rowing, this is just a guess.
If you do the energy balance and assume a 25% efficiency, this corresponds to a value of 200 watts
mechanical energy output and about 400 calories would be heat which then be transferred to the air
via the evaporation of water on the skins surface.

Jon Isaacs

Ernie Trish said:

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 terrymorse.combikeOpen ↗

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

Quoted message said:

Quoted message said:

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.

Some of points to consider:

1. The website you are looking at is a website selling Infra-red

sauna's as a

Quoted message said:

method of weight-loss. Not exactly a trust worthy site.

2. Consider the mechanism of sweating and how it cools you. The body

only puts

Quoted message said:

water on the surface of the skin, it does not vaporize it. Putting

water on

Quoted message said:

the surface of the skin does not actually consume much energy. It is

only when

Quoted message said:

that water is evaporated by the air that heat is transferred from the

body to

Quoted message said:

the air and thus the body is cooled.

Now in a Sauna, that heat is coming from the Sauna rather than from

exercise so

Quoted message said:

the body does not actually have to provide any energy in order to

vaporize that

Quoted message said:

water, it is simply getting to hot because the Sauna is adding

calories in the

Quoted message said:

form of radiant heat to the body.

So while evaporating sweat does require calories, those calories do

not

Quoted message said:

necessarily need to be food calories and in the case of the sauna,

they would

Quoted message said:

seem to come from the sauna rather than the persons metabolic

processes.

Quoted message said:

2. The body is about 25% efficient in converting food energy

(calories) into

Quoted message said:

mechanical energy. The other 75% is heat and sweating cools you off.

If you want to do this exactly, you need to measure these things

exactly and

Quoted message said:

that includes measuring your actual energy expendature rather than

just

Quoted message said:

estimating it.

Your question is sort of like asking if one needs to include the heat

lost

Quoted message said:

through the radiator when computing the fuel mileage of the car. The

answer is

Quoted message said:

that the heat lost through the radiator is accounted for via the

efficiency of

Quoted message said:

the engine.

So when they suggest that you burn 350 x 45min/30 min = 525 calories

rowing,

Quoted message said:

this is just a guess. If you do the energy balance and assume a 25% efficiency, this corresponds
to a value of 200 watts mechanical

energy output

Quoted message said:

and about 400 calories would be heat which then be transferred to the

air via

Quoted message said:

the evaporation of water on the skins surface.

Jon Isaacs

Good answer. One thing I've seen in various studies is that with a Concept II type rower, the ratio
of mechanical output to total energy burned is lower due to accelerating and decelerating the whole
body mass. Greater efficiency can be achieved with a constrained setup.

Phil Holman

In article said:

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.

Quoted message said:

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 pegasus.rutgers.edu~elflordOpen ↗

[email hidden] (Ernie Trish) wrote in message
news:<[email hidden]>...

Quoted message said:

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.

I have also been reading about calories required to help the body sweat during excersise (example
article at: infraredsauna.netmedicalinformation.htmlOpen ↗). 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.

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

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 (infraredsauna.netmedicalinformation.htmlOpen ↗) 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.

[email hidden] (Ernie Trish) wrote in message
news:<[email hidden]>...

Quoted message said:

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.

I have also been reading about calories required to help the body sweat during excersise (example
article at: infraredsauna.netmedicalinformation.htmlOpen ↗). 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

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

Quoted message said:

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 (infraredsauna.netmedicalinformation.htmlOpen ↗) 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

Quoted message said:

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

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

Quoted message said:

Ernie Trish said:

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.

W K said:

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

In article <[email hidden]>, "Phil Holman"

Quoted message said:

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

Quoted message said:

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

Quoted message said:

develops the sweat mechanism.

Right

Quoted message said:

Based on the referenced article (infraredsauna.netmedicalinformation.htmlOpen ↗) I
had made an

assumption that the sweat mechanism

Quoted message said:

itself was an active process (pores dilating or some such) that had a calorie

value associate with it.

The sweat mechanism is designed to cool the body like a radiator cools the body. The energy cost to
the body ought to be compared to the energy cost of running an internal combustion engine's water
pump. It takes a bit but it has little to do with the heat equations.

Quoted message said:

Based on the referenced article (infraredsauna.netmedicalinformation.htmlOpen ↗) 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

Quoted message said:

the commonly sited calorie expenditure numbers for rowing (300-350 calories per 30 minutes).

Forget that article, they are trying to convince people to buy their equipment so that they can burn
fat without exercising. It just doesn't work that way. Consider the water pump analogy.

Quoted message said:

Do I have it correct that all the calorie estimates are not measured directly

but derived from assumptions about wattage, joules, and metabolic efficiency?

Probably. If you have a way of actually measuring your work output, then you should be able to get a
reasonable measurement of how much work you have actually done.

If you were riding a bicycle equipped with a PowerTap, it would be continuously measuring your power
output and storing it so it tells you how much actual work you have done. From that you can estimate
the number of calories you have burned.

But numbers like 300-350 calories for 30 minutes of rowing are just ball park figures that could
vary by a factor of two in either direction.

Quoted message said:

Is this how the Polar heart rate monitors estimate calories? I am guessing not.

I believe the Polar HRMs guess your work output based on your accumulated heart rate information.
This again is just a guess and obviously may differ between individuals.

Making the actual measurements of calories burned is quite complicated I believe and beyond the relm
of trying to guess it based on HR or other factors.

For my money, i would believe the number based on the actual work performed would be the most
accurate, but such devices are relatively expensive.

But please, when you see a website trying to sell InfraRed Sauna's as a weight loss technique, be
suspicious and be cautious about buying their potentially bogus hype.

Jon Isaacs

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

Quoted message said:

In article <[email hidden]>, "Phil Holman"

Quoted message said:

From heart rate there must be an estimate of power output from a

user

Quoted message said:

Quoted message said:

programmed set-up value. From that an integration of varying heartrate (power output)

together

Quoted message said:

Quoted message said:

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

In article <[email hidden]>, "Phil Holman"

Quoted message said:

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

Quoted message said:

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 (infraredsauna.netmedicalinformation.htmlOpen ↗) 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

Quoted message said:

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%.

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, [email hidden] sfu.ca~rcousineOpen ↗ President, Fabrizio Mazzoleni Fan Club

In article <[email hidden]>, "Phil Holman"

Quoted message said:

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

Quoted message said:

In article <[email hidden]>, "Phil Holman"

Quoted message said:

From heart rate there must be an estimate of power output from a

user

Quoted message said:

Quoted message said:

programmed set-up value. From that an integration of varying heartrate (power output)

together

Quoted message said:

Quoted message said:

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

"I used to rock and roll all night, and party every day. Then it was every other day. . . ."

- Homer J. Simpson

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

Quoted message said:

In article <[email hidden]>, "Phil Holman"

Quoted message said:

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

Quoted message said:

In article

<[email hidden]>,

Quoted message said:

Quoted message said:

Quoted message said:

"Phil Holman" <[email hidden]> wrote:

>
> From heart rate there must be an estimate of power output from a

user

Quoted message said:

> programmed set-up value. From that an integration of varying heartrate (power output)

together

Quoted message said:

> with say a 25% efficiency, will come up with an estimate of

calories

Quoted message said:

Quoted message said:

Quoted message said:

> burned. Likely not very accurate, IMO +/- 10%.
>

You mean when the rowing machine says I burned 831 calories, it

might

Quoted message said:

Quoted message said:

Quoted message said:

not be exactly that many?

--Harold Buck

What do you think Harold? Does the machine know your efficiency or

your

Quoted message said:

Quoted message said:

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

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

Quoted message said:

W K said:

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

Quoted message said:

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.

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

Quoted message said:

In article <[email hidden]>, Ernie Trish

Quoted message said:

Quoted message said:

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

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

Quoted message said:

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

Quoted message said:

In article <[email hidden]>, "Phil Holman"

Quoted message said:

From heart rate there must be an estimate of power output from a

user

Quoted message said:

Quoted message said:

programmed set-up value. From that an integration of varying heartrate (power output)

together

Quoted message said:

Quoted message said:

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?

I think Harold's sarcasm would have been more obvious if he'd written "831.000000000" Calories.

Andy Coggan

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

Quoted message said:

Quoted message said:

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