Calories X Joules Readings

[ppinho]

Ibike Screen

Ibike_Screen.png (418.79 KiB) Viewed 5681 times

Hi,

I have bought an Ibike Dash a couple of weeks ago and I am still learning how to use it.

During my studies, I found out that Calories measures that I get from Ibike Dash are very small compared with my old Polar CS600 for the same distance e aprox same effort.

Today I noticed that energy measure in Ibike for Mac software for one specific workout was the following:

Energy = 569 Kj

Cals Burn = 544 Kcal

As far as I could research, one joule is equivalent to 0,2390 cal.

If I consider the joule measure as correct and apply the conversion above, Calories result is 2.380 Kcal, much closer to my Polar readings.

Could you help me to understand what is wrong in my setup / readings?

Regards,

Paulo Pinho

[Velocomp]

Please post the ride file that goes with your image

[ppinho]

Hi,

This is the file of my ride.

Paulo

[ppinho]

Hi,

Any comments about my ride file?

Paulo

[KenS]

I think you have a problem with your math.
If 1 joule= 0.2390 cal then 569 kJ = 136 kcal and not 2,380 kcal (you divided by 0.2390 instead of multiplying)

The human body is only about 25% efficient at producing energy, so to produce 1 kcal of energy you need to burn 4 kcal.
To produce 136 kcal you need to burn 544 kcal

I don't know about Polar but my Garmin 708 is notoriously inaccurate at calculating calories burned since it does not use the iBike power to do that. It is usually at least a factor of 2 larger

[ppinho]

KenS,

Thanks for your response... Your math makes sense. I did a mistake when I tried to explain the difference between the polar e ibike readings.

Regards,

Paulo

[mgh1196]

Okay, another perspective on this...I find my iBike calories burned to me at least half of what my polar indicates wearing both monitors at the same time. I have used the polar for years and have tested its accuracy to amount weight lost relative to calorie deficit (-3500kcal=1 pound of weight) many times at different multiples. Meaning, when calorie intake is at maintenance level and I burn 500kcal per day that puts me at a 3500 calorie burn deficit for a one week and will result in one pound lost for that week. So, I am doubting the accuracy of the iBike calorie burn as compared to my polar as I have proved it accurate. Any thoughts or correcting my logic?

[racerfern]

The iBike calculates the calories (or kj) burned by your exercise; not by living. I find the iBike kJ burned to be spot on for the effort.