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Indoor Cycling - Where has my calorie burn gone?

Former Member over 9 years ago

Ok, I'm living with the various flaws with the 235 at the moment in terms of the 24*7 monitoring and issues with the Optical HR monitoring as I am happy to use a strap while exercising and getting an accurate HR and calorie burn. I do a lot of indoor cycling at the moment and use the Indoor cycling mode. I have been happy up until now with the results. However, the last two rides appear to be way off. For an ride of 60-70 mins I would expect to see in the region of 600 - 900 calories depending on intensity. E.g:

> 3rd Feb Typical ride of 1hr 11 mins.
Distance 35.78km
Calories 797
Ave HR 119
Max HR 128
Training affect 2.4

> 7th Feb Ride of 1hr 20 mins
Distance 34.06km
Calories267
Ave HR 119
Max HR 143
Training effect 1.0

> 8th Feb ride (today) 1Hr 1 min
Distance 23.86km
Calories 219
Ave HR 113
Max HR 126
Training effect 1.0

The last two rides are vastly different to all of my others with the first example being typical of previously recorded calorie burn. I have checked my HR zones and my Max HR setting etc and they are OK and haven't changed. My RHR is normally between 48 and 50 bpm.

This doesn't appear to be a GC issue as the low calorie burns were recorded by the watch before I sync'd.

Any suggestions? I am rapidly losing faith with this...:(

0 timgrose over 9 years ago

Can you post all the GC links to try and get a better idea what is happening here.

So no settings changes. Presume no firmware changes or resets between the 1st and 2nd rides?

Done anything else, like running?

What is your max HR set to?

What are you using to capture speed/distance?

0 Former Member over 9 years ago

247

Can you post all the GC links to try and get a better idea what is happening here.

So no settings changes. Presume no firmware changes or resets between the 1st and 2nd rides?

Done anything else, like running?

What is your max HR set to?

What are you using to capture speed/distance?

Hi Tim, no changes or resets and no running! I checked all of the settings such as MAX HR, HR Zones etc and all seemed OK.

However, I did call the helpdesk and they said they had issues with GC over the weekend which may have caused this. I have since done 3 Indoor Rides and they seem to be back to normal thankfully. So hopefully a one-off :-)

One interesting thing, I did see that GC had added about another 250 calories in the Steps line immediately after the ride, so it seems that the 24*7 tracking has registered the calorie burn and realised that I had burnt more than the activity stated and gave me some back! :)

I also noted that if I manually changed the calories in the ride activity then the extra calories added in the steps line reduced by the same amount. I'm concluding from that information that the total calorie burn for the day is solely determined by the 24*7 HR tracking. The steps line is showing the delta of the total calories burnt over BMR - Calories burnt from activities recorded on the watch. Maybe I'm wrong but it would be useful if Garmin would communicate how the top level calculations are arrived at so we can understand what we are looking at.

0 Former Member over 9 years ago

Tim, to answer your other questions, my MAX HR is set to 172.
The watch is picking up the cadence sensor from a Tacx Neo smart trainer. Distance can be out somewhat when using ERG mode, but I'm not too bothered by that as I usually look at the data in Strava which is imported from the Zwift application used. Unfortunately the Watch doesn't pick up the power meter in the turbo for some reason so to see that I have to use Strava as it does get imported into Strava for Zwift which does detect the sensor.

0 Former Member over 9 years ago

Well. it appears to have happened again.

Here is a ride from yesterday with the correct calories (653). Note training effect is 2.2

https://connect.garmin.com/modern/activity/1044484762

Here is a ride from this morning. Slightly less time but calories only 203. Note training effect is 1.0. Also no additional calories added to the steps line in the activity tab in GC,

https://connect.garmin.com/modern/activity/1045499297

One thing that is common with the tree times I have had the issue is that I turned off trainer (and the sensors) before I saved the ride on the watch. Didn't mention it before as it seemed a bit of a tenuous link. But could this be corrupting the data somehow? Is this some kind of bug?