I love my Fitbit, but I want to play with the data myself, not just look at the graphs the fine folks at Fitbit have decided I should see. Fortunately, there’s a great step-by-step guide with a script to download Fitbit data into a Google Drive spreadsheet, which handles interfacing with the Fitbit API.
I downloaded my data beginning with April 2012 when I started using Fitbit. There were 18 days without any steps recorded (days when I forgot to wear the Fitbit or it ran out of batteries, plus a few days when it broke and I had to have it replaced), which I eliminated from the analysis. Other than those few days, I have a complete record of my activity for the past 21 months, which is pretty cool.
I used Python to plot the daily step counts along with a time-smoothed rolling average to make it easier to see long-term trends.
The most obvious features to me are the high-step-count spikes during the summer, when I’m most likely to go adventuring outdoors on the weekends. To get a better sense of the distribution of my steps, I plotted a histogram:
I average about 10,000 – 11,000 steps per day, but there’s a lot of variation. I usually end up recording at least 12,000 steps on days when I bike to work, because I find that each pedal rotation registers as a step. I suspect that the tail on the left side of the histogram (<5000 step days) are mostly days when I was sick or otherwise feeling down, because I generally find it downright difficult to walk fewer than 5000 steps in a day unless I have a cold or similar.
Finally, I broke the histogram down by days of the week. It got a little messy to look at, so I used gaussian kernel smoothing to turn the histogram into a density plot that’s easier on the eyes:
Most of the days are similar to each other, but Saturday clearly has the most variation, and the most days with very high step counts. In fact, I walk 15,000+ steps 17% of the time on Saturdays, but less than 10% of the time on other days of the week. And on that note, the dog and I are going for a walk.
Here’s the code I used to generate the graphs:
[gist https://gist.github.com/8090081 /]