Calorie meter

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Janickic
Paddler
Posts: 3
Joined: August 27th, 2006, 1:00 am

Calorie meter

Post by Janickic » August 27th, 2006, 1:04 am

Does anyone know how accurate the calories burned indicator is on the erg? I would imagine that different drag factors/different sized people would make a difference. If this is the case, does anyone have a way to compensate for this or calcualte your actual calories burned?

jamesg
Marathon Poster
Posts: 4254
Joined: March 18th, 2006, 3:44 am
Location: Trentino Italy

Post by jamesg » August 27th, 2006, 4:25 am

The monitor calculates kCals from the power we supply to the flywheel, (which is accurate), multiplying by the W/kCal conversion factor and by an efficiency constant (4) which implies we are fuel cells with efficiency 25%. It also adds on 300 kCal/h which is thought to be what's produced if alive and moving up and down the slide etc.

Your weight would alter the 300 value, as also your rating and stroke length. Drag will have no effect separate from our own Wattage.

My guess is that the accuracy is around 10% at power levels of the order of 150W, and improves the higher the power delivered.

Any inaccurcay depends on the constant 4 (no idea if anyone has ever even tried to measure this, or if it remains constant at all work levels) and the 300.

Interesting on the erg is the fact (at least on my PM2) that the kCal readout is the only measurement albeit indirect of the amount of work done. And even this is falsified by the 300 free of charge: if you move the handle an inch every five seconds, you'll be credited with the 300 kCal/h.

We can also weigh ourselves before and after, add the weight of any water drunk and multiply the total by 500 kCal/kg, which is the latent heat of steam. Very rough no doubt, but fine for day to day comparisons and it's impossible to fiddle the books.
08-1940, 179cm, 75kg post-op (3 bp).

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