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BSTARR67
12-03-2009, 02:39 PM
Many questions in these forums are about measuring calories. There is a lot of mention of measuring calories using nothing except for heart rate data.

The point of my post has been made by a few others in these forums, but mostly indirectly. I feel it needs to be clear to users that:

Calories cannot be measured by heart rate monitoring and duration alone. Errors of 30% to 50% are common, especially for the most- and least-conditioned folks.

Using heart rate alone is widely promoted by Polar, of course. Garmin usually doesn't have to rely on this, since it has GPS and footpod solutions that work quite well. The moderators and Garmin experts in these forums have been very helpful to those who want accurate calorie counts in situations that aren't perfectly-suited to a Garmin solution.

More-detailed user-profiling can help make heart rate-only calculations more accurate. It doesn't need to be the ultra-credible New Leaf profile, either.

But let me assure you, heart rate alone cannot be used for accurate calorie calculation. If you don't believe me, read through the following example:

• Calories vary directly with distance and body weight, nothing else. (Everyone agrees on this.)

• I weigh the same as many national-class distance runners.

• I can run 6 miles in 48 minutes at max effort (average HR = 170).

• A national class runner can run 10 miles in 48 minutes at max effort (average HR = 170).

• A calorie estimate using HR plus duration would claim we both burned the same number of calories, but in fact the national class runner burned 67% more calories.

• (In fact, the national class runner’s average HR would probably be lower than mine during his 10-mile run.)

For us long-time runners, the Garmin Forerunner line is a dream come true. Now we can, forever, put aside all the other baloney-based calorie numbers.

LIONHILL1
12-14-2009, 10:27 PM
Hi, I appreciate your clarity on the heart rate measuring calories. I was wondering what your suggestion would be for myself, a person that would like to know how many calories I am burning during my cardio/weight training workouts. I love the features of the Garmin 305, especially the GPS, however I would like to know info about my indoor routine as well. I was previously using the Sportsline watch that I had to press to get my heart rate (which was a pain sometimes). I would compare the calorie count to my Diet & Excercise Assistant to see if the figures were in the same ballpark amount and it usually was (calories was based on time, activity, weight, age, and gender).
Since I've picked up running over the last several months, I decided that I needed more info than my "starter" watch could provide. When you say that a more detailed user profile would be more accurate than "New Leaf" can you be a little more detailed as far as what has to be done in the profile section?
Also would what suggestion would you have for using the 305 indoors without the foot pod because I don't have one as yet? Should the workout be entered manual after the calories are figured out because it seems like you can't adjust anything that is downloaded?
I know I asked alot, however I just want to get as much info as possible so that you can help me with trying to get the results that I am looking for.
Thanks

t_smit
12-14-2009, 11:07 PM
It is true that heart rate alone does not determine the absolute calorie expenditure for any given person. However, it is also true that distance and body weight alone don't determine the absolute calorie expenditure.

To use the previous example, a world class runner can do 10 km in somewhat under 30 minutes, and they'll burn a given amount of energy doing that. Part of it is purely required to cover that distance, but if they're doing 10 km in half an hour, then they spend more energy fighting wind resistance than they would if they covered that distance in one hour, since wind drag increases with at least the square of the speed.

Your heart rate is a good measure of the relative calorie expenditure rate, which is particular to you and the shape you're currently in. If you get a proper VO2max test done, then you can find out the absolute relationship between your heart rate and your calorie expenditure. So long as you stay at more or less the same fitness level, that relationship will be valid. If you increase your fitness level, then your heart rate for a given calorie expenditure will go down.

So tracking your heart rate as a function of how you exercise is still valid and can give you a guide to changes in your fitness level at least. If you run the same route regularly, at more or less the same speed, then you'll likely find that over a period of a couple of months your average heart rate on that route will decrease.

BSTARR67
12-15-2009, 09:28 AM
When you say that a more detailed user profile would be more accurate than "New Leaf" can you be a little more detailed as far as what has to be done in the profile section? ...

Also would what suggestion would you have for using the 305 indoors without the foot pod because I don't have one as yet?

Things like a more detailed user profile, a New Leaf profile, or an obviously unobtainable VO2 max test are all just band-aids. The only good solution is also an outstanding one: get the Garmin footpod. When calibrated, this footpod is very, very accurate. You'll only be frustrated (especially with your indoor workouts) until you get one.

And when I say accurate, I mean in measuring distance. I'm still not sure Garmin is using a good calorie formula to estimate calories from distance.

... Bob

JDTEREX
12-17-2009, 10:15 AM
I made my own formula calibrated from a track workout I did. Here's how to do it on a track, but it will work with any piece of sports equipment that will measure your Calories.

Step 1) After a rest/easy day, strap on your Garmin device and head out to the track (or any piece of sports equipment that will measure Calories)

Step 2) Warm up, stretch, then begin exercising.

Step 3) Start slow. Every 2 minutes, increase your effort. Make your Garmin lap automatically to make it easier. If you're not outside on a track or on your bike, have an assistant record the number of Calories burned during each interval.

Step 4) In an excel document, record your heart rate and Calories burned per minute for each interval.

Step 5) Make a scatter plot with Calores burned per minute is on the y-axis and heart rate on the x-axis

Step 6) Add a trendline. Make sure it is a linear trendline, and select show formula on chart. This formula tells you how many calories per minute you burn at a given heart rate.

The formula y = ax - b, y = Cal/min, x = heart rate. a = slope, b = intercept.

Ex. I made a curve whose formula is y = 0.1416x - 8.303. I went to the indoor rock climbing gym and exercised for 76.5 minutes at an average 105 beats per minute.

My Cal/min is 0.1416*(105)-8.303 = 6.656Cal/min. My total Calories for the workout is now 6.656*76.5 = 502Calories.

This assumes of course that I burn the same number of calories rock climbing for 76.5 minutes at 105 beats per minute as I would running for the same time and heart rate.

MARTOWL
01-04-2010, 04:04 PM
Many questions in these forums are about measuring calories. There is a lot of mention of measuring calories using nothing except for heart rate data.

The point of my post has been made by a few others in these forums, but mostly indirectly. I feel it needs to be clear to users that:

Calories cannot be measured by heart rate monitoring and duration alone. Errors of 30% to 50% are common, especially for the most- and least-conditioned folks.

Using heart rate alone is widely promoted by Polar, of course. Garmin usually doesn't have to rely on this, since it has GPS and footpod solutions that work quite well. The moderators and Garmin experts in these forums have been very helpful to those who want accurate calorie counts in situations that aren't perfectly-suited to a Garmin solution.

More-detailed user-profiling can help make heart rate-only calculations more accurate. It doesn't need to be the ultra-credible New Leaf profile, either.

But let me assure you, heart rate alone cannot be used for accurate calorie calculation. If you don't believe me, read through the following example:

• Calories vary directly with distance and body weight, nothing else. (Everyone agrees on this.)

• I weigh the same as many national-class distance runners.

• I can run 6 miles in 48 minutes at max effort (average HR = 170).

• A national class runner can run 10 miles in 48 minutes at max effort (average HR = 170).

• A calorie estimate using HR plus duration would claim we both burned the same number of calories, but in fact the national class runner burned 67% more calories.

• (In fact, the national class runner’s average HR would probably be lower than mine during his 10-mile run.)

For us long-time runners, the Garmin Forerunner line is a dream come true. Now we can, forever, put aside all the other baloney-based calorie numbers.

Hi BSTARR67: I must differ with your opinion on this issue. As a statement of fact you are correct and HR cannot be used to effectively estimate calorie consumption without laboratory calibration of the individual athlete and then is still subject to significant error. However, the 405CX and Suunto devices use Firstbeat technologies that rely on R-R calculations or beat by beat analysis of HR data. Here is a summary of white papers from the Firstbeat site. http://www.firstbeat.fi/index.php?page=5 Some of the scientific papers that were published are referenced in the white papers. If the individual athlete has a good estimation of their activity level, the calorie consumption can be accurate within 5-10%. The 405CX and the Suunto devices use this technology and should provide similar information. I have a Suunto T6 and a 405CX. Both give very similar calorie expenditure results for the same course, etc. Take a look at the information on this site and tell me what you think. I have found the distance estimates for calorie expenditure to grossly overestimate (when I forget my HR strap for example).

CAROLUSJG
09-19-2011, 07:58 AM
What I've understood is that if it's not FirstBeat equiped, the ANT+ calculation remains only an estimation.

Tisztul_A_Visztula
02-07-2013, 04:47 AM
• Calories vary directly with distance and body weight, nothing else. (Everyone agrees on this.)


I deem your statement is falling apart due to the fact that the human body has a changing metabolic efficiency as a function of speed, cadence, HR, grades etc.

There are not too many white papers measuring it while running/jogging, but if you check the white papers on cycling you can observe some nice curves showing the different level of efficiency of the same person at different power or cadence.