A big THANK YOU to Lindsey for posting this question on the Shape Your Weigh 2011 Facebook group. Her question was:
Kimmy, I was wondering how much of a discrepancy there is between the calories burned on your treadmill versus on the Bodybugg? I heard that gym machines can be off by as much as 20% or so. Or can you tell how many on the Bodybugg for just 1 activity?
I couldn’t let this question sit for more than a day – I was extremely anxious to tackle it. I have to say, I’m surprised by the results. It brings forth a few questions. “Which monitor is better? Can you really afford those extra calories? Are these high end gadgets worth their expensive price tag?”
Activity Selected
- Walk/Run combo on the treadmill
Length of Activity
Calorie Monitors Used
- Standard calorie monitor on treadmill
- Polar F6 Heart Rate Watch Monitor
- BodyBugg
Observations During Warm-up
I started my run like I do every other with a 1-2 minute walk. I noticed the calorie burn being reported between the watch and the treadmill were pretty close. Maybe off by 10-15 calories.
Observations During the Run
This is where all hell started to break loose. I kept a close eye on my Polar F6 heart rate monitored while watching the treadmill monitor. In a matter of minutes the two were completely out of synch and off by as much as 50-75 calories.
Comparing the Data
The proof is in the pictures. These are pictures taken of my treadmill and my Polar F6 watch at the end of the run.

As you can see there is a BIG difference between the Polar F6 Heart Rate monitor (289 calories in 30 minutes) and the treadmill (155 calories in 30 minutes).
What the BodyBugg Reported

The BodyBugg reported my 30 minute run burned 320 calories.
Table of Results
Treadmill |
155 calories |
Polar F6 Watch |
289 calories |
BodyBugg |
320 calories |
Conclusion and Opinion
I have to admit, I’m not really surprised that the treadmill was so far off from the other two monitors when it came to my calorie expenditure. The treadmill wasn’t programmed for my weight, and it wasn’t doing a heart rate reading.
I’m a little surprised to see a 31 calorie difference between the BodyBugg and the Polar F6 heart rate monitor. 31 calories doesn’t seem like a lot but in the course of a year 31 calories a day = 11,315 total calories.
1 pound of fat = roughly 3500 calories
11,315 total calories divided by 3500 calories = 3.2 lbs per year
My opinion is to continue monitoring with my BodyBugg and Polar F6 but I will keep in mind that even these two high end, expensive devices are not without fault and that there is margin for error. At the end of the day, whether or not you choose to buy them or use them is up to you.
Let me know what you think!