I have been using RunKeeper to keep track of my walks and bike rides for a while now. In addition to distance and pace, RunKeeper offers an estimate of calories burned that is most likely derived based on my weight/age and distance information. Last month I had an idea to compare these estimates with those provided by my Bodymedia tracker, and to do that, I had to conduct an experiment, which lasted for about two weeks. The estimates provided by both trackers turned out to be very close.
The experiment involved taking ten random walks during the lunch time and on weekends, with distances varying between 1.7 and 3.8 miles, on mostly flat surface (streets of Manhattan and Hudson River park). To be able to compare Bodymedia and RunKeeper estimates, I had to keep timing my walks: the time when the walk started and time when it was finished. Fortunately, Runkeeper stores than information on their website. The rest was easy: Runkeeper records the estimate of calories burned for each walk, and Bodymedia estimate can be easily obtained using interactive dashboard (use the slider to isolate the estimate between any time points).
After completing ten walks, I lined up estimates from both trackers in Excel file. The chart below shows differences in estimates from Runkeeper (blue bars) and Bodymedia (red bars). As you can see, they were pretty close, although Runkeeper’s estimates tend to be slightly lower:
The median difference between Runkeeper and Bodymedia was – 34 calories. Based on this comparison, I can conclude that (in my case), Runkeeper can be used to track calorie expenditure during walking. Of course, Bodymedia still has an advantage: compared to other trackers that only track calories burned while in motion, Bodymedia measures your caloric expenditures even when you are stationary, i.e., even when you are sitting, standing, sleeping, etc. And trust me, depending on your metabolism, that could be a lot of calories that are unaccounted for!
Question to QS community: has anyone done similar comparisons, using Fitbit or other tracker?
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