Figuring out calories burned?

"VBadJuJu" none@ wrote

Highly accurate too at least as to speed (and therefore distance, avg
speed etc). Recently there was one of those automated radar speed
things down the street off and on for about 9 weeks. Coming down the
hill on my way out to ride I could verify the read out vs the radar
thingie.

Bike "computers" are simple wheel revolution counters, they're all as accurate
as the tire size input.


FWIW, 13 - 15 miles works out to about 1000 calories at 10.5 - 11.5
MPH average for me.

That sounds off by a factor of 4 or so, it's way too high unless that is up a
very steep hill. You can't accurately measure calories without measuring
watts, and that's a difficult thing to do, the equipment is available to do
that (e.g. Powertap), but it's expensive.

On Wed, 01 Sep 2004 16:56:51 GMT, "chris christanis"
wrote (more or less):

I had a cheap Bell computer that did it for me but it fell off (cheap). So I
bought a cateye but it does not tell you calories burned. Anyway to figure
this out?

Pretty much, calories burned per kilometre/mile is constant, whether
you're going fast or slow. (Walking a mile burns as many calories as
running a mile.)

If you've kept records of your previous rides, with the distance gone
and the calories your old Bell computer told you, then you can do a
quick calc of how many calories per mile the old computer was
more-or-less using.

Then count the kilometres, and multiply by your chosen cal/mile
number.



The Longer version

One question is, how accurate was your old Bell computer anyway...

With cycling, because you can get up to speeds where air resistance
becomes significant, this isn't entirely true, but it's still close
enough for jazz.

The key factors for bikes I'd say a
- weight of the rider + bike
- smoothness or lumpiness of the surface.

I've looked at all sorts of sites that discuss calories/hour, and the
range I've seen goes from about 30 calories/mile to 65 calories/mile.
And these take no account of surface. And often faster riding uses
fewer calories/mile, according to these sites.

If anyone wants my spreadsheet that works out calories/mile for riders
of different weights and average speeds (Excel 5 format), just
contact me off-list, and when I return from my holidays I'll email it
to you.

I pretty much use a 38cal/km (60cal/mile) for me as a 200lb guy on a
heavy bike*.

(This actually prompted me to go and weigh my bike for the first time.
I'd sort of reckoned it as 15kg, but it's actually 20kg (45lb) -
before I load anything into the panniers or the bar bag!)

So just use your mileometer, and then multiply by the number you feel
comfortable with.

Figures I've seen on web-sites include:
==============================
Calories burnt/10 mins
Woman Man
Wt (lb) 123 170
5.5mph 36 49
9.4mph 56 74
racing 95 130


And on another:
"Cycling burns about 0.15 to 0.17 calories per minute, per kilogram
(divide your weight in pounds by 2.2 to get kilograms) of body weight,
for fast riding. There is wide variation in this formula, but this
gives you a start.

For example, 0.17 calories/minute-kilogram x 60 minutes x 73 kilograms
(160-pound person) equals 742 calories needed for an hour of fast
cycling.

For aerobic riding, the range is lower, around 0.10 to 0.15 calories
per minute, per kilogram of body weight. Very easy recovery riding is
lower yet."



--
Cheers,
Euan
Gawnsoft: http://www.gawnsoft.co.sr
Symbian/Epoc wiki: http://html.dnsalias.net:1122
Smalltalk links (harvested from comp.lang.smalltalk) http://html.dnsalias.net/gawnsoft/smalltalk

On Wed, 01 Sep 2004 16:56:51 GMT, "chris christanis"
wrote (more or less):

I had a cheap Bell computer that did it for me but it fell off (cheap). So I
bought a cateye but it does not tell you calories burned. Anyway to figure
this out?

Pretty much, calories burned per kilometre/mile is constant, whether
you're going fast or slow. (Walking a mile burns as many calories as
running a mile.)

If you've kept records of your previous rides, with the distance gone
and the calories your old Bell computer told you, then you can do a
quick calc of how many calories per mile the old computer was
more-or-less using.

Then count the kilometres, and multiply by your chosen cal/mile
number.



The Longer version

One question is, how accurate was your old Bell computer anyway...

With cycling, because you can get up to speeds where air resistance
becomes significant, this isn't entirely true, but it's still close
enough for jazz.

The key factors for bikes I'd say a
- weight of the rider + bike
- smoothness or lumpiness of the surface.

I've looked at all sorts of sites that discuss calories/hour, and the
range I've seen goes from about 30 calories/mile to 65 calories/mile.
And these take no account of surface. And often faster riding uses
fewer calories/mile, according to these sites.

If anyone wants my spreadsheet that works out calories/mile for riders
of different weights and average speeds (Excel 5 format), just
contact me off-list, and when I return from my holidays I'll email it
to you.

I pretty much use a 38cal/km (60cal/mile) for me as a 200lb guy on a
heavy bike*.

(This actually prompted me to go and weigh my bike for the first time.
I'd sort of reckoned it as 15kg, but it's actually 20kg (45lb) -
before I load anything into the panniers or the bar bag!)

So just use your mileometer, and then multiply by the number you feel
comfortable with.

Figures I've seen on web-sites include:
==============================
Calories burnt/10 mins
Woman Man
Wt (lb) 123 170
5.5mph 36 49
9.4mph 56 74
racing 95 130


And on another:
"Cycling burns about 0.15 to 0.17 calories per minute, per kilogram
(divide your weight in pounds by 2.2 to get kilograms) of body weight,
for fast riding. There is wide variation in this formula, but this
gives you a start.

For example, 0.17 calories/minute-kilogram x 60 minutes x 73 kilograms
(160-pound person) equals 742 calories needed for an hour of fast
cycling.

For aerobic riding, the range is lower, around 0.10 to 0.15 calories
per minute, per kilogram of body weight. Very easy recovery riding is
lower yet."



--
Cheers,
Euan
Gawnsoft: http://www.gawnsoft.co.sr
Symbian/Epoc wiki: http://html.dnsalias.net:1122
Smalltalk links (harvested from comp.lang.smalltalk) http://html.dnsalias.net/gawnsoft/smalltalk

On Wed, 01 Sep 2004 16:56:51 GMT, "chris christanis" wrote:

I had a cheap Bell computer that did it for me but it fell off (cheap). So I
bought a cateye but it does not tell you calories burned. Anyway to figure
this out?

Lifeform is nice software to track food and exercise.
http://www.fitnesoft.com/


---
"BitwiseBob" - Bob Anderson
Eugene Oregon

On Wed, 01 Sep 2004 16:56:51 GMT, "chris christanis" wrote:

I had a cheap Bell computer that did it for me but it fell off (cheap). So I
bought a cateye but it does not tell you calories burned. Anyway to figure
this out?

Lifeform is nice software to track food and exercise.
http://www.fitnesoft.com/


---
"BitwiseBob" - Bob Anderson
Eugene Oregon

"Kevan Smith" wrote in message
...
On Wed, 1 Sep 2004 15:26:20 -0700, "GaryG"
from Posted via Supernews,
http://www.supernews.com wrote:

"chris christanis" wrote in message
...
I had a cheap Bell computer that did it for me but it fell off (cheap).
So
I
bought a cateye but it does not tell you calories burned. Anyway to
figure
this out?


I've included a Calorie and Watts Calculator in my CycliStats ride log
and
training diary software ( http://www.CycliStats.com ).

This is really obvious, but any calorie calculation uses depends on what
you
think the calorie burn rate is. The burn rate is also logarithmic; that
is,
the faster you go, the number of calories burned per unit of time
increases on
a logarithmic curve. Therefore, finding an accurate base is important.
There
are also other factors to consider, such as elevation gain, wind, bike
position, weight, etc, which also go into the base.

The Calorie and Watts Calculator built into CycliStats takes into account a
bunch of variables, including: rider weight, bicycle weight, distance,
speed, elevation gain, average headwind, rider position on the bike, rolling
resistance factor, and air temperature. Average headwind and rider position
are the two most significant variables (after rider weight and speed which
are known quantities). The underlying calculation (from a sports physiology
Master's thesis...not mine) first calculates Average Watts. It then
converts that into Calories burned (and also displays calories per mile/km,
per minute, per hour, and equivalent fat pounds/kg burned).

The calculation can be completely automatic, or the user can override some
of the assumed variables. For instance, rider position on the bike is
assumed to be more "aero" as you ride faster, but you can override this
assumption for each ride.

Is it an "accurate" number? Well, outside of a sports lab, everything is
just an estimate. But, I've compared the numbers for Watts and Calories
from CycliStats with many others that I've seen, and I'm pretty confident
that they are reasonable for most rides. As a test, I recently plugged in
Lance Armstrong's numbers for his Alp d'Huez time trial and came very close
to what I've heard reported as his average wattage output on that climb
(around 450 watts!).


All in all, I consider it impossible to get an accurtate measurement
outside
lab conditions. That's why I ignore all that stuff. A ballpark figure is
good
enough for me, and the really important thing, anyway, is to use the same
method each time.

Agreed...it's all just an estimate. For most folks, 40 calories per mile
would probably be a reasonable number to use (a little more if you're heavy,
and a little less if you're light).


Here's a good free site to do it:

http://www.primusweb.com/fitnesspart...e/calculat.htm

By tracking results over time, you can get a general idea of how much you
need
to ride to lose or maintain weight. Of course, you also have to keep track
of
how many calories you eat, and that's another kettle of fish.

CycliStats tracks calories burned for each ride, and shows summaries for
each week, month, and year (or any other time frame you choose), along with
a whole bunch of other stats. You can download a free, fully functional
30-day trial version from the website ( http://www.CycliStats.com ).

--
~_-*
....G/ \G
http://www.CycliStats.com
CycliStats - Software for Cyclists


--
Kevan Smith

"Kevan Smith" wrote in message
...
On Wed, 1 Sep 2004 15:26:20 -0700, "GaryG"
from Posted via Supernews,
http://www.supernews.com wrote:

"chris christanis" wrote in message
...
I had a cheap Bell computer that did it for me but it fell off (cheap).
So
I
bought a cateye but it does not tell you calories burned. Anyway to
figure
this out?


I've included a Calorie and Watts Calculator in my CycliStats ride log
and
training diary software ( http://www.CycliStats.com ).

This is really obvious, but any calorie calculation uses depends on what
you
think the calorie burn rate is. The burn rate is also logarithmic; that
is,
the faster you go, the number of calories burned per unit of time
increases on
a logarithmic curve. Therefore, finding an accurate base is important.
There
are also other factors to consider, such as elevation gain, wind, bike
position, weight, etc, which also go into the base.

The Calorie and Watts Calculator built into CycliStats takes into account a
bunch of variables, including: rider weight, bicycle weight, distance,
speed, elevation gain, average headwind, rider position on the bike, rolling
resistance factor, and air temperature. Average headwind and rider position
are the two most significant variables (after rider weight and speed which
are known quantities). The underlying calculation (from a sports physiology
Master's thesis...not mine) first calculates Average Watts. It then
converts that into Calories burned (and also displays calories per mile/km,
per minute, per hour, and equivalent fat pounds/kg burned).

The calculation can be completely automatic, or the user can override some
of the assumed variables. For instance, rider position on the bike is
assumed to be more "aero" as you ride faster, but you can override this
assumption for each ride.

Is it an "accurate" number? Well, outside of a sports lab, everything is
just an estimate. But, I've compared the numbers for Watts and Calories
from CycliStats with many others that I've seen, and I'm pretty confident
that they are reasonable for most rides. As a test, I recently plugged in
Lance Armstrong's numbers for his Alp d'Huez time trial and came very close
to what I've heard reported as his average wattage output on that climb
(around 450 watts!).


All in all, I consider it impossible to get an accurtate measurement
outside
lab conditions. That's why I ignore all that stuff. A ballpark figure is
good
enough for me, and the really important thing, anyway, is to use the same
method each time.

Agreed...it's all just an estimate. For most folks, 40 calories per mile
would probably be a reasonable number to use (a little more if you're heavy,
and a little less if you're light).


Here's a good free site to do it:

http://www.primusweb.com/fitnesspart...e/calculat.htm

By tracking results over time, you can get a general idea of how much you
need
to ride to lose or maintain weight. Of course, you also have to keep track
of
how many calories you eat, and that's another kettle of fish.

CycliStats tracks calories burned for each ride, and shows summaries for
each week, month, and year (or any other time frame you choose), along with
a whole bunch of other stats. You can download a free, fully functional
30-day trial version from the website ( http://www.CycliStats.com ).

--
~_-*
....G/ \G
http://www.CycliStats.com
CycliStats - Software for Cyclists


--
Kevan Smith

On Thu, 02 Sep 2004 11:51:18 GMT, Peter Cole
wrote:

"VBadJuJu" none@ wrote

Highly accurate too at least as to speed (and therefore distance, avg
speed etc). Recently there was one of those automated radar speed
things down the street off and on for about 9 weeks. Coming down the
hill on my way out to ride I could verify the read out vs the radar
thingie.

Bike "computers" are simple wheel revolution counters, they're all as
accurate
as the tire size input.


FWIW, 13 - 15 miles works out to about 1000 calories at 10.5 - 11.5
MPH average for me.

That sounds off by a factor of 4 or so, it's way too high unless that is
up a
very steep hill. You can't accurately measure calories without measuring
watts, and that's a difficult thing to do, the equipment is available to
do
that (e.g. Powertap), but it's expensive.



HR monitors should be better in this regard, as at least they take into
account how hard you're working (and know data like your weight, sex, age,
etc.). Power monitoring would be great, too.

--
Bob in CT
Remove ".x" to reply

On Thu, 02 Sep 2004 11:51:18 GMT, Peter Cole
wrote:

"VBadJuJu" none@ wrote

Highly accurate too at least as to speed (and therefore distance, avg
speed etc). Recently there was one of those automated radar speed
things down the street off and on for about 9 weeks. Coming down the
hill on my way out to ride I could verify the read out vs the radar
thingie.

Bike "computers" are simple wheel revolution counters, they're all as
accurate
as the tire size input.


FWIW, 13 - 15 miles works out to about 1000 calories at 10.5 - 11.5
MPH average for me.

That sounds off by a factor of 4 or so, it's way too high unless that is
up a
very steep hill. You can't accurately measure calories without measuring
watts, and that's a difficult thing to do, the equipment is available to
do
that (e.g. Powertap), but it's expensive.



HR monitors should be better in this regard, as at least they take into
account how hard you're working (and know data like your weight, sex, age,
etc.). Power monitoring would be great, too.

--
Bob in CT
Remove ".x" to reply

"chris christanis" wrote in message ...
I had a cheap Bell computer that did it for me but it fell off (cheap). So I
bought a cateye but it does not tell you calories burned. Anyway to figure
this out?

This is a very tricky question.

Having investigated this in the past, I know there is no agreed,
accurate method of determining the calories used.

A few observations, though.

1) Any method that does not take account of the speed at which you are
cycling is pure rubbish.
2) Unless you are cycling on the flat at a steady speed, any method
that does not take account of the total moved mass is pure rubbish.
3) Conversly, any method which ties the calories burned to the moved
mass without taking account of the altitude gained/lost and the amount
of acceleration/decelerations is pretty much rubbish.
4) Any method that does not take account of the wind speed is likely
to be wildly inaccurate if the w/s is over about 5 mph (consider that
if you are cycling with a groundspeed of 15mph, your airspeed will
vary from 10 to 20 mph tail/head wind at this w/s. At 12 mph, the
difference would be 3 to 27 mph)

5) Within a fairly wide range, you can probably find a figure or
algrorithm that will give you any result you want, if you research
enough sites/books/articles.

The method I used to *ESTIMATE* the calorie burn was as follows.

a) Find a step aerobics machine which has a calories burned* readout.
b) Use an HRM and set the machine to various resistances. For each
resistance setting, wait until your heart rate stablises, and note the
Hr/Calories readings.
c) Plot a graph of these figures
d) Use an HRM that will give you a mean Hr for your ride, and use that
against your graph to determine your approximate calorie burn.

* Try and determine if the calorie readout is the number of calories
calculated from the kg/m raised on the machine, or whether the machine
introduces a "fudge factor" to account for the inefficiency of human
power generation/delivery. If it is the former, it will be a
considerable underestimate of the calories burned. All the heat you
produce is on top of the energy used to effectively raise your body
mass the distance used in the calculation.

If you can do the maths, you can use the Hr/Cal figures to produce an
equation, but as the relationship is non linear, it's not that easy

Apart from the above, I would say that the algorithm given based on
mean Hr and weight has the best chance of being accurate, although
both this, and the moethod I outline above will not be too good if
there is a large variation in Hr during your ride.