Most accurate calorie indicator.

[T.M.H.N.E.T]

Congratulations on needlessly and somewhat anally complicating the measurement

PS: Expenditure based on HR closest to accurate ?

 

[fenlandpsychocyclist]

Congratulations on needlessly and somewhat anally complicating the measurement

PS: Expenditure based on HR closest to accurate ?

Heart rate linked to oxygen demand, oxygen demand linked to effort put into the pedals. Sounds good to me.

 

[amaferanga]

A rough estimation. 100Wh = 86 kCal. Your body is about 60% efficient at producing power iirc so that's 143kCal. So for a 12st man doing a flatish 70 miles averaging 100w (14.8mph) we get 677 kCal.

Not sure about your maths.

100W will burn about 370 kcal/hour (accounting for human efficiency you get a roughly 1:1 equivalence of kJ to kcal -- Watts = Joules/sec so it's easy to work out kJ if you know Wattage). So if 100W will indeed lead to an average speed of 14.8 mph (which seems quite a high speed to me for not many Watts) then over 70 miles you'd burn around 1750 kcal.

Anyway, any calorie estimate based on speed or HR will be way off for most people. My Garmin Edge 500 uses HR if it's available and comes up ridiculously low. I know this because I often ride with a power meter so know typically how many Watts I put out to average a given speed for a given route. I know that if I use the kJ figure as reported when I use my power meter that I'll be as close to knowing the kcal figure as with any other practical means.

For your average cyclist assuming 400-800 kcal/hour will be as good an estimate as any Garmin or HR monitor IMO.

 

[amaferanga]

Heart rate linked to oxygen demand, oxygen demand linked to effort put into the pedals. Sounds good to me.

HR doesn't tell you how many Watts you're producing. Two cyclists could have identical HR for a ride and even if they're the same weight, one could be putting out way more Watts that the other. It's the Watts that'll tell you how many kcal you burn, not the HR.

So calorie guessing using HR sounds bad to me.

 

[GrasB]

Not sure about your maths.

100W will burn about 370 kcal/hour (accounting for human efficiency you get a roughly 1:1 equivalence of kJ to kcal -- Watts = Joules/sec so it's easy to work out kJ if you know Wattage). So if 100W will indeed lead to an average speed of 14.8 mph (which seems quite a high speed to me for not many Watts) then over 70 miles you'd burn around 1750 kcal.

I plucked that out of my brain so I may have got the wrong baseline number. 14.8mph comes from me on the hoods of my road bike averaging 103w round a concreet oval track. So that's lowish hoods on an aerodynamically clean normal tubed road bike.

 

[fenlandpsychocyclist]

I think the main thing to learn from my original post comparing three devices on the same ride, is that many calorie estimators over-read.

Meaning if you're using one of these diet-tracker apps on a smartphone, you could well put in your food consumption for the day, then add in
the (incorrect) calorie burn for the same day ... and come out with a false number.

All in all i think its best to ignore the calorie numbers shown on any bike computer + eat less + go to bed hungry every night to loose weight.

 

[T.M.H.N.E.T]

Go to bed hungry.

What?

 

[amaferanga]

Go to bed hungry maybe, but make sure you eat at the right time so your body can recover. Less important if you're just riding for fun, more important if you're training.

 

[bof]

Heart rate is a good (not perfect) indicator of Calories burned when your gender, age, weight and V02Max are also known. (type in "Prediction of energy expenditure from heart rate monitoring during submaximal exercise" into Google ).

Polar monitors have a fitness indicator (at least the model I had did) which give a decent approximation to V02Max, so I trusted their Calorie estimates. If you can find some device that allows you to increase power in a test incrementally and get a reasonably accurate measurement of power and HR at the same time, you can work out V02Max with some online calculators.

I have just started using a Garmin Etrex 30 which measures HRM, but yet to locate a Calorie calculator that can use the GPX files it creates. Does anybody know of one?

.

 

[HLaB]

I have just started using a Garmin Etrex 30 which measures HRM, but yet to locate a Calorie calculator that can use the GPX files it creates. Does anybody know of one?

.

Have you tried Garmin Connect, Strava or RidewithGPS, they take gpx files and output Calorie data, I'm unsure of the accuracy though!

 

[bof]

Have you tried Garmin Connect, Strava or RidewithGPS, they take gpx files and output Calorie data, I'm unsure of the accuracy though!

Thanks - Garmin Connect does not do it for the etrex 30 GPXs - it just gives an average and, IIRC, max HR figure, which in themselves are no use. I will try the other two out when I am not at work.

 

[amaferanga]

Heart rate is a good (not perfect) indicator of Calories burned when your gender, age, weight and V02Max are also known. (type in "Prediction of energy expenditure from heart rate monitoring during submaximal exercise" into Google ).

One scientific paper from 2005 doesn't really convince me. All I know is that no calorie counter, be it on a Garmin or website, has ever given me a figure that's consistently close to the kJ figure from my power meter. I'd say HR is very hit-and-miss for calorie estimates and therefore using a rule of thumb will be better for most people.

Interestingly, my Garmin Edge 500 (and FR310xt) give a better calorie estimate for me when I'm not wearing the HR strap (from doing my regular commute with power meter, with Garmin and with Garmin+HR).

 

[bof]

Have you tried Garmin Connect, Strava or RidewithGPS, they take gpx files and output Calorie data, I'm unsure of the accuracy though!

I have now tried with RidewithGPS and I had forgotten I already use the site fore saving routes - showing what a bookmark can do to web branding. Anyway, I was able to upload the GPX directly from the eTrex 30 in "USB mode" where the Garmin looks like a disc drive,and once I had set up zones, it performed a Calorie calculation. I suspect it exaggerated the Calories a bit, but it produced an interesting set of data from the GPX.

Note that if you save the GPX with Mapsource, it loses the HRM data.