Calories burn with and without heart rate monitor

The eTrex seems to record legs at 1 minute intervals and the F2 at 1 second intervals.

The etrex 30 manual is here: http://static.garmincdn.com/pumac/eTrex_10-20-30_OM_EN.pdf. What you seek is on page 32. I see here: http://www.aukadia.net/gps/lw3_0.htm the one second recording is possible "I do know of people who record once per second" but that will theoretically fill up your memory pretty fast "In combination with these setttings, the Archive should be set to 'Daily'. NB that if you record densely, eg once per second, you might have to set the Archive to 'When Full' as this will occur within a few hours.

It looks like there is a 10,000 track point limit on your etrex which will limit the length of a track set to 1 second recording to 167 minutes. Now I could do that on flat ground but, with 8,000 feet of altitude gain, I'm thinking it would take me closer to 180 minutes. That is a 20% grade! Should be worth 9-10 METS.

The etrex 30 manual is here: http://static.garmincdn.com/pumac/eTrex_10-20-30_OM_EN.pdf. What you seek is on page 32. I see here: http://www.aukadia.net/gps/lw3_0.htm the one second recording is possible "I do know of people who record once per second" but that will theoretically fill up your memory pretty fast "In combination with these setttings, the Archive should be set to 'Daily'. NB that if you record densely, eg once per second, you might have to set the Archive to 'When Full' as this will occur within a few hours.

It looks like there is a 10,000 track point limit on your etrex which will limit the length of a track set to 1 second recording to 167 minutes. Now I could do that on flat ground but, with 8,000 feet of altitude gain, I'm thinking it would take me closer to 180 minutes. That is a 20% grade! Should be worth 9-10 METS.

Thanks FL! I set the eTrex30 to record every 10 seconds. Hopefully, I can set the F2 to the same interval (it's not on me right now, I'll check tonight). I always remove prior tracks from my devices before creating a new one so memory should not be an issue. (maps are loaded on a 32GB SD card).

Hopefully, I can set the F2 to the same interval

Your only options on the F2 are Every Second and Smart. I would stick with Every Second. I have no idea how twisty your trail is but I might choose 2 or 3 seconds for the etrex of that is an option. I'm guessing what you are aiming for is getting the same distance on both devices.

BTW, speaking of what you are aiming for, are you primarily interested in the calorie burn differences between the three devices when all three are watching your HRM? Are you going to measure a round trip or just the ascent? Do you plan to repeat the activity without and HRM? That would be cool but a lot of work. I hope it is a pretty day wherever you are planning to do this :).

BTW, speaking of what you are aiming for, are you primarily interested in the calorie burn differences between the three devices when all three are watching your HRM? Are you going to measure a round trip or just the ascent? Do you plan to repeat the activity without and HRM? That would be cool but a lot of work. I hope it is a pretty day wherever you are planning to do this :).

My primary goals are to understand which device is most accurate when I hike long distances (distance and elevation gain/loss) and what my 'real' calorie burn might be. You'll see below one device said I burned 841 calories (F2) and the other 2,931 (Vivosmart).

Here is what I did yesterday - this hike should be somewhere around 9-11 miles and about 8,000 feet gain/loss. It was a 1 way trip up the mountain. Took the tram down. ;)

Vivosmart on right wrist (paired with HRM-RUN)
F2 on left wrist (paired with same HRM-RUN and paired with Tempe, data recording = Smart)
eTrex 30 (also paired with HRM-RUN and same Tempe, data recording at 10 second intervals)

Unfortunately, the eTrex30 lost battery power (even though the bars showed full just prior to the hike, but died within 1.5 hours - another gripe for another thread), so I changed the batteries, but lost a couple of miles as a result.

Some of my observations, that I cannot explain:

- eTrex30 picked up temperature readings, but the F2 did not.
- eTrex30 picked up heart rate, F2 did not. Yet the F2 returned a calorie burn of 841.
- Vivosmart returned a calorie burn of 2,938., and a distance of 7.5 miles (as compared to 11.8 for the F2)

Link to my eTrex30 activity: https://connect.garmin.com/modern/activity/703852190
Link to my F2 activity: https://connect.garmin.com/modern/activity/703842143

If anyone has any insight into these discrepancies, would love to hear it! Also, curious why only 1 device (of the eTrex30 and F2) picked up HR and temperature. Both were paired, I swear!

Thanks!

If anyone has any insight into these discrepancies, would love to hear it!

Well, first we have to get personal. May I have your age, sex, and weight? Do you know your Garminized BMR?

As for your missing sensors, I am afraid we are going to have to chalk that up to pilot error. Your HRM-RUN and Tempe are ant+ slave sensor devices and will connect to up to at least 50 master devices simultaneously. The fact that your F2 Activity has no HR, Run Dynamics or temperature information simply indicates that these sensors were not detected at the outset of your hike. When you begin an activity, between the time you select the Activity type and then accept start, your F2 will cycle through all sensors you have paired and its GPS and either confirm that each is connected or offer you the opportunity to skip each one individually. If this did not happen, you did not have the HR or Tempe enabled in your watch settings. Or you skipped them. There really is no other explanation. I'm betting that you never saw your heart rate on the fenix during your hike. 847 calories seems like a good number for and eight hour uphill hike.

It does not appear that you recorded the hike as an Activity on your Vivosmart. 3,000 calories make no sense at all. Is that the total accumulated calories you read off the band at the end of the hike? Was your Vivosmart paired with your HRM-RUN? Looks like you set out at 7AM and finished up at 15:00 more or less. Again, I need your personal details (you can PM them if you prefer) but 3,000 calories is a lot. For me to burn that many calories by 3 in the afternoon, I would have to run more than 16 miles at a 10:00 Pace or walk twice that far at a 15:00 Pace.

As for the distance your Vivosmart recorded, I am quite surprised it came up short. Have you carefully calibrated your running and walking step length? Even if you have, I would have expected the Vivosmart to have reported a distance estimate much longer than actual. The reason for this is that, on an extreme uphill march like you just completed, you will be taking substantially shorter steps than you would on level ground but your device has no way to "know" your steps are shorter than "normal". It just counts them and multiplies the number of steps by whatever value you fed it for average walking step length. You might wan to revisit that number. The widely accepted rule of thumb for walking is .43 time your height. A 66" tall person will, on average, had a 28" walking step size.

Your fenix 2 consistently gave you lower elevations than your etrex. Do you remember how each was set up/calibrated. Did you encounter elevation signs on the trail that you compared each to? Have any idea which was more accurate? I would have guessed that, if they were set up the same that they would have given you the exact same readings. Nearly 200' of difference seems like a little much to me. As it is, 20' of difference at the start turned into 181' at the end. The pressure was very stable while you were hiking beginning at 1011 and ending at 1007

102°F at 10 AM 5,000 feet above sea level? That seems really unlikely. The high in town was only 81° that day and it didn't get that hot until noon. Where were you wearing the tempe? Helps to keep the out of direct sunlight but also away from your body heat. It can be tricky finding the ideal spot.

Did you have a good time?

Well, first we have to get personal. May I have your age, sex, and weight? Do you know your Garminized BMR?

Sending personal info. via PM - I don't know my Garminized BMR - where do I find that?

As for your missing sensors, I am afraid we are going to have to chalk that up to pilot error.

I'll go with that for the moment, except that I have never successfully had both units produce HR and Temperature readings using the same sensors. It always seems that the first device it finds, it uses. Unfortunately, I don't have the HR and Temp readings available on my devices' main data page, so I don't consciously look while I hike.

I'll try again this weekend and pay closer attention.

The calorie reading on the Vivosmart still seems way off, though.

As for the distance your Vivosmart recorded, I am quite surprised it came up short. Have you carefully calibrated your running and walking step length?

No, I did not calibrate my walking or running step length. I never thought that should make a huge difference, especially since I'm of average height. But I will, and report back.

Your fenix 2 consistently gave you lower elevations than your etrex. Do you remember how each was set up/calibrated. Did you encounter elevation signs on the trail that you compared each to? Have any idea which was more accurate?

I calibrated both devices in my house to match my forerunner. All my devices are calibrated to read 400 ft above sea level in my kitchen. There were no elevation signs on this trail. I'll check both devices against a known elevation sign at my first opportunity. Historically, the eTrex30 was always within 5 ft of the signs. The F2 is always a couple of hundred feet different from the eTrex30.

102°F at 10 AM 5,000 feet above sea level?

Yeah, this one was definitely user error. I thought I had it in an external pocket of my backpack, but it fell out and was dangling by a carabiner on the outside. It wasn't 102 degrees, but it did get pretty warm and we were fully exposed to the sun.

Did you have a good time?

Definitely! Gorgeous desert mountain hike. Group was a bit slower than I'm used to (so a lot of stoppage time to regroup), but it was a great day! Thanks!

FL - Will take all your suggestions and 'run' with them (no pun intended). By the way my GBMR is 1,422 so that makes sense. Thanks for all your help! ~Karin

I have had a couple of brief exchanges with Vivo group people on this subject. They have admitted that HRM linked calorie expenditure estimates the Vivo's (fit and smart) are producing appear to be materially inaccurate and are looking into it. However, they have also informed me that they are seeing some absurdly high levels as well. We may have seen that once here. EricFOhio's 304 calorie 30 minute walk. That could be a good number if Eric is 200 lbs. and 70 years old or 300 lbs and 30 years old. KWAGATHA's 2,938 12 mile, eight hour, 8,000' hike initially struck me as high but both online calculators agree on 4,712 for that so it seems we have another very low number depending on exactly where she got it from.

It would be nice to have more data points while the Garmin guys and gals are paying attention to this.

Garmin 620 calories fluctuations

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.

I'm having the same issue with my Garmin 620. I'm a 63 year old woman, weigh about 108 pounds, resting pulse about 47. Garmin's estimate of my VO2 max has ranged from 39 to 49 (it was always in the high 40s until I reset the device and now it says 40, although my fitness level hasn't changed). Anyway, this week I did two runs in a row. The first, without a HRM - 35 minutes at a 9:48 pace. Garmin said I burned 304 calories. The next day I ran 6.77 miles in 65 minutes - using my heartrate monitor - and Garmin said I burned 376 calories. Really? That's nuts.