Yesterday, I blogged about using my fitness tracker data to answer the question, do you burn more calories if you walk faster. In response, one of my friends in the Fediverse asked: “Is the model even good enough to show the efficiency improvement from walking to running?” And I was like, “aww, man, I was hoping not to have to run that data, but now that you asked I’m going to have to. 😉” So today I’m redoing my analysis, this time including my running activities in addition to my walking activities.
Before digging into the data, I did a little research into my friend’s implied assumption that there’s an efficiency improvement from walking to running, and it turns out whether or not that’s true depends on what you mean by “efficiency improvement.” Does “efficiency” mean conserving energy, or does it actually mean maximizing energy use because your goal is weight control? Well, it turns out that running is less efficient at conserving energy and more efficient at burning calories; the top answer on this page does a good job of explaining why.
And this is indeed what I see when I regenerate yesterday’s graphs with my running activities included.
From the second graph above, we see that:
- The lower bound of calories per mile is higher for running than walking, meaning that the most energy-efficient running is less efficient than the most energy-efficient walking.
- However, the upper bound of calories per mile is lower for running than walking, i.e., the least efficient walking is less efficient than the least efficient running. This feels like it makes sense to me, because I believe your gait and style of motion are more constrained when running.
Just for kicks, I sorted the activities in my spreadsheet by average speed, split them at 4.5 MPH, and calculated calories per hour and calories per mile for the two groups summed together:
Putting all this together, my conclusion from yesterday is augmented as follows:
If your exercise is time-constrained, you’ll (obviously) burn more calories the faster you go whether you run or walk. If your exercise is distance-constrained, you’ll probably burn slightly more calories running than walking.
Caveat: I don’t run much anymore due to a health condition, so there isn’t a lot of chronological overlap between the running and walking samples. Since people’s bodies change over time, that could have influenced the results shown above, though I don’t think it’s likely that it could completely explain the differences between running and walking.