Garmin Edge 800 - kcal

badly_dubbed

Hey guys,

Was wondering if someone would take a look at my training session from Tuesday night:

http://connect.garmin.com/activity/76020823

Is it me or is the edge 800 under estimating calories used here or does that seem accurate??

My polar would normally read into the thousands as it was a hard session!

Any info is appreciated chaps thanks!

SBezza

Without knowing what power you were outputting you can only guess, but what is reported looks reasonable to me. I wouldn't expect much more than 1000 calories for that sort of ride. It really does depend on how much power you put out with regards to calories used.

ut_och_cykla

If I did a ride that length I'd guestimate no more than 900kcal - so it might be a bit low - but it depends on what weight your dragging round too - if you are a 150kg sumo wrestler it is perhaps too low ... but if you're around 70 or so ...as a guide its probably close enough

badly_dubbed

I'm 26 and weigh in at 70kg forgot to mention that!

SBezza,Thanks, I guess my polar is over estimating then?

I was deffo feeling like I was working, last 1.5 mile sprint was killer

amaferanga

Without knowing the power you produce its hard to say, but for me a hard 90min ride would be more like 1200-1400 kCal (from PowerTap). So 900kCal might be a bit low, but then again it might not be.

Bronzie

Rough guesstimate for 90 mins @ 21mph would be around 250W average given your weight => c.1000cal/hour so I'd say the Garmin is underestimating.

There are a lot of variables in there though.

EDIT: Was this a group ride? If so, would obv. be less due to drafting.

Ands

The calorie output on my Garmin is a lot less than on my Polar. My Polar would calculate ~600 cal per hour on an average triaiing ride, whereas the Garmin is more like 400-450. Not sure which of the two is more accurate but if you read the Garmin forums, other people experience the same with Garmin v Polar.

joeyhalloran

I heard that the Polar was more accurate at giving calories burnt than Garmin...just something i heard.

rickwiggans

Read the Garmin user forum, for the 800. Seems underestimating calories is a known issue on the 800.

Ands

rickwiggans wrote:

Read the Garmin user forum, for the 800. Seems underestimating calories is a known issue on the 800.

There is a known issue with underestimating, but this is resolved with the latest firmware upgrade. When I first got my 800, it would give me a calorie consumption of <100 for a 2 hour ride. Now the issue is 'resolved' in that the readings are more realistic. Whilst the current 800 readings are not comparable with the Polar readings, there seems little to suggest that the Polar's high readings are any more accurate than the Garmin's lower readings.

badly_dubbed

Cheers ands, what firmware do you run?

And yea this was a group ride

ut_och_cykla

Group ride - - Garmin is probably close & polar way out - but who knows!

Pokerface

Previously Garmin was way OVER-estimating cals. Now it seems they have tried to fix the problem and gone too far the other way!

amaferanga

It varies from device to device and between firmware versions as well. My 310xt under-reads compared to my PT by about 50%

Ands

badly_dubbed wrote:

Cheers ands, what firmware do you run?

And yea this was a group ride

I'm on v2.1.

badly_dubbed

thanks mate, same.

just did 46miler solo technically (with a buddy but not drafting) 2.5hrs at 18.2mph average and it told me i burnt 1249cal.

i reckon its not far out..... ?

http://connect.garmin.com/activity/76390438

Alex_Simmons/RST

Most of these devices are calorie messtimators. Ignore them.

doyler78

The line I've seen trotted out when people complain about the Polar's accuracy is that it relies on accurate v02 max figures entered and most people don't have this. Polar's attempts at calculating a figure equivalent to v02 max (own index) tends to over estimate and as the Polar sets the v02 max to the own index number in the absence of user input from a real test it then tends overestimate calories. Mine personally overestimates calories by about 1/3 (from memory) however what I do remember is that it was always of the same magnitude which I found interesting.

I'll have to put the theory to the test one of these days when I get round to getting a v02 max test done

Bronzie

badly_dubbed wrote:

just did 46miler solo technically (with a buddy but not drafting) 2.5hrs at 18.2mph average and it told me i burnt 1249cal.

That's only 500cal/hour - sounds a bit low to me.

Based on my own figures (similar weight to you) I'd reckon on average power of 190-210W for that sort of speed with 600m climbing ==> c.700-800cal/hour.

You can play with the figures yourself here:
http://bikecalculator.com/veloMetric.html