Remember my rant a little while ago about how you shouldn’t think of exercise and food as an equation to balance? Or my post about not using the exercise component of calorie counting apps? Well, I just wanted to add a little more to that conversation today.
I use a Garmin watch to track my runs and occasionally I’ll look at the “calories burned” out of curiosity. After a pretty fast longish interval run I noticed that the calories burned seemed rather low so I started scrolling back through and was puzzled to find a shorter easier run that supposedly resulted in a very similar caloric expenditure. That left me wondering how Garmin determined the calories burned during a run. I looked it up and it turns out that it’s related to heart rate. Sometime the heart rate monitor is wonky and (especially when it’s really cold out) will register a heart rate that would be more likely seen when I’m sitting on my butt than when I’m out booking it through speed work. That means that my Garmin (erroneously) registers minimal exertion and thinks that I’m not burning very many calories.
Today I decided to do a little experiment. I wore my Garmin, as per usual, which is synched to my Strava account. I also fired up the Nike+ Run Club app for the first time in ages and I set out on an easy(ish) 10k run. After the run, I also entered the time spent running at the closest average pace into myfitnesspal. All of these apps have my height and weight. Any guesses what the results looked like?
Garmin: 463 calories
myfitnesspal: 517 calories
Nike: 526 calories
Strava: 1371 calories!!!!
Now, I have no idea how many calories I actually used during this run, I’d wager Garmin was probably closest to the mark considering that the heart rate monitor seemed to be working properly. But Strava, what the actual hell?? Considering that Strava gets all of it’s data from my run directly from Garmin I find it amazing that it estimated I burned nearly three times as many calories as Garmin thought I did. I’m sure that if I had other apps and trackers I would have gotten slightly different results from all of them.
All this to say, if you’re exercising and tracking calories burned, you probably shouldn’t give that number too much weight. Try to think of exercise as giving you health and fitness rather than taking away calories and weight.