Calories burn with and without heart rate monitor

Calories burned is a hugely difficult thing to measure accurately unless under lab conditions and even then it's tricky. The figure is just a guide so consistency is the important thing choose using with HRM or without and stick to it. With the HRM must give yo a better comparative figure as the calc will be related to effort over a time period so that would be my preference.

IMHO there is a BIG problem here. I do not normally record activities on my VS since I use a Fenix or Edge for intentional exercise. However, in a series of recent experiments I was conducting for a different reason, I noticed that a simple 2 mile walk performed over the exact same course at very similar paces were producing very low and somewhat erratic calorie expenditure numbers on my Vivosmart when paired with an HRM while producing slightly low but consistent burns without a HRM. Here are some results:

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The yellow shaded rows are activities recorded with three different HRM's. The METS column represents the value for that activity provided by the 2011 Compendium of Physical Activities. HR Calc Values were taken from here: http://www.calories-calculator.net/Calories_Burned_By_Heart_Rate.html. GBMR is the number of calories Garmin thinks I burned in the form of BMR during the elapsed time of the activity (1,801 per day). IE BURN is the difference between the calories awarded me by GC and the GBMR and is therefore the component of calories Garmin awarded me for the activity that is attributable to intentional exercise.

In case anyone wants to check my numbers or compare their own, I am a 59 year old male that is 69" tall and weighs 155 lbs. My current VO2 Max is about 40 and resting heart rate when fully recovered is in the low 50's. Not a couch potato but certainly not an elite athlete either.

One other note. When I started this, I had never bothered to fine tune my Custom Step Length and GC was reporting my walks as 20-25% longer than actual. I did fix my Custom Step Length and that seems to have a downward impact on Garmin's calorie expenditure estimates for activities recorded without an HRM. This was a bit surprising as I would have thought it would all be about steps and time but perhaps not.

I've reported this to Garmin on a preliminary basis but would love to get some clean data from others to support my case. I think the key elements are same course, same pace, and tune up your Custom Step Length before you start collecting data.

BTW the 2011 Compendium of Physical Activities can be found here: http://download.lww.com/wolterskluwer_vitalstream_com/PermaLink/MSS/A/MSS_43_8_2011_06_13_AINSWORTH_202093_SDC1.pdf among other places. The running codes are in the 12,000's. The walking codes are in the 17,000's.

The way you use it is to look up the METS value for whatever activity you are engaging in. Multiply that value times your weight in kg and multiply that times the number of hours you were engaging in that activity.

For example—looking at my activity #1. Walking on a firm level surface at an average speed of 3.7 mph most closely matches code 17200 "walking, 3.5 mph, level, brisk, firm surface, walking for exercise" which has a METS value of 4.3.

4.3 X 70.3068 (my weight in kg) X 0.6563333333333333 (39 minutes and 23 seconds expressed as a fraction of one hour) = 198.42219452 (round to 198).

Given that these numbers are adjusted for neither sex nor age, they may be rougher than some other estimates that incorporate these values. Nevertheless, absent other measuring techniques, this has been the gold standard in science since the numbers were first published in 1993. There is a good Wikipedia entry on the subject here: http://en.wikipedia.org/wiki/Metabolic_equivalent

EricFOhio, I just realized my response to the thread you were kind enough to start did not really address your own personal experience. The consensus wisdom is that HR based calorie expenditure estimates are way better than METS. In fact, one white paper published by FirstBeat predicts an error of 20-35% by heart rate vs. 60% by motion alone. To JSRUNNER's comment, all of these outside the laboratory estimates are just SWAGS—some a little more sophisticated than others. Without your age, weight, distance and average speed, it is hard to gauge the veracity of either of the numbers you got for a 30 minute walk, though, if the walks were essentially the same and you have correct personal information entered in GC and synced to your band, a 2X difference between HR and no HR is pretty hard to believe. You notice that my results are backwards from yours as in much lower with HRM. Here is a really absurd one from this morning where Garmin awarded me less calories for a two mile walk than it should have given me for lying in bed for the same period of time: https://connect.garmin.com/modern/activity/696404334

I think there is just some kind of error in their calculations.

Yesterday's Three Walks

Each of these should have been worth 160 to 180 calories. I am at a total loss to explain the extreme swings but will keep collecting walk data on my rest days and start doing multiple short runs on my training days to accumulate enough information to convince Garmin to straighten out whatever is wrong here.

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The morning walk https://connect.garmin.com/modern/activity/696404334 was done with a Garmin HRM3 heart rate monitor which seemed to function correctly. The 35 calories I was awarded for this 35 minute walk were 9 less than my Garmin BMR for the same period of time. The midday walk https://connect.garmin.com/modern/activity/696552370 was done with no HRM and garnered me enough calories to have been a 2 hour 40 minute walk at that pace as opposed to the 33 minute walk it actually was and nearly double what I got for a six mile interval run https://connect.garmin.com/modern/activity/696639694 completed later that same day. The afternoon walk https://connect.garmin.com/modern/activity/696673096 at 144 calories is the only one that came in at a rational level.

What you're missing is "steps". It'd be interesting to see how many "steps" were recorded for the first two. When you walked the dog, was the leash on the same arm as the Vivo?

As for the one with the HR, I've lately been interested in how these formula are obtained, and I'd really like to see some of the actual data that they're based on. Nevertheless, in Googling around, I've learned that the algorithms that include HR aren't very accurate and are only applicable to aerobic activity in certain heart rate zones. 80-90 is pretty low. My Edge 800 essentially stops counting calories on descents on my MTB when my HR drops below about 110, so it isn't surprising that the calorie count is so low using HR.

Well I can fill in those blanks for you since my custom step size (2.685') was the same for all three. 2.11 Miles = 4,149 Steps. 1.89 Miles = 3,717 Steps. 2.00 Miles = 3,933 Steps. I'm with you on the calorie calculation. The Shapesense Calculator http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx refuses to compute a calorie expenditure with a heart rate below 107.

But really . . . 35 calories in 30 minutes is below my Garminized BMR for that period of time. And 792 for 33 minutes at 3½ mph? The is more wrong here than bad models. This is just plain bad math. Forget being in the right zip code—these numbers are on the wrong continent.

The dog is pretty lively and circles me a lot so the leash gets passed from hand to hand in front and behind my back. I don't think it is interfering with step counting.

Planning to do six today. Three with the same HRM (Garmin HRM1B) and three without.

Merlin

BTW this is Merlin—my research assistant. He is enjoying all of the extra exercise.

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The one in the middle of the chart (12:34), strikes me as what your calories could be if you included the calories from both your BMR and your walking activity. I just did 2 miles walking, and for that I have about 170 cals (recorded as an activity, with no HRM), but on the device it shows about 800 cals, as that's including those from my BMR. It also includes the walking calories I've burned today outside of the 2 mile "activity".

The other option, could the "792" calories in you chart be the calories you burned above your BMR for the day, and not for the 2 miles?

Thanks for participating Jim. My understanding has always been that whenever Garmin reports calories related to an activity it is what is often referred to as a "gross" number meaning your BMR + the extra calories related to the activity vs "net" which is over and above your BMR. What I was reporting up in #6 was a comparison of three activities plucked directly from the Garmim Connect Web application. I did not take any of those numbers off of the band. My total BMR as assigned by Garmin at the end of that second activity would have been 1801/24*13 or 975.

Here is what all of yesterday looked like in the Web app:
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F2 stands for fenix 2