Here we are, nearly two months into 2018. Many people make New Year’s resolutions involving fitness - now seems a good time to take stock.

In January, the Gyms were crowded with newbies. Barre classes had to turn people away when the classes filled. There were waiting lists for your favorite yoga studio. And as for the trendy spin studios - they were sold out all week.

And for Fitbit ($FIT) users and runners using apps like Strava and Nike Run Club to track their runs, there is a sharp spike upwards in activity in January.

When it comes to activity trackers, it goes a bit deeper than just the New Year's Resolution thing  - especially when we’re looking at Fitbit usage. The fitness trackers that people wear (and often sleep in), really can't lie, and what we see when looking at the data is a huge uptick in activity in January and a general fall off as the months wear on, and then another uptick in the summertime and a tapering off in the fall. We wondered why so we took a deeper dive and noticed some other trends.

I’m a runner, so one look at this graph pointed out a very obvious correlation between the spike in January and slight up and down movement until spring. Runners training for spring marathons hit their heaviest mileage in January and February. Runners may hit a half marathon in early January. Those 13.1 miles will lead to a 16 mile, 18, mile, 20 mile, and sometimes 23 mile run in the eight weeks prior to a marathon. The last long run of roughly 12 miles or so would typically be about four weeks out. Then, of course, the big 26.2 mile day. Training data for the Los Angeles Marathon, Boston Marathon, Rome Marathon, Paris Marathon, and Big Sur Marathon, just to name a handful would pretty faithfully follow the spikes through January and March or April, when all of these marathons take place. If I had to bet, just from seeing my friends’ data on Strava and the Nike Run Club app, the data for these two running apps would deliver the same ups and downs that correlate with a marathon training program.

Another look at the data on this chart shows a basic uptick in June. It's not hard to figure that one is due to better weather, more outdoor activity, and summer break.

The data also shows a sharp decline as we head towards the winter holidays. Think about your life—does your daily commitment to the number of steps you take or workout regimen stay steady through the holidays? Chances are, like most of us, the answer is no. So while people settle in for food and desserts and libations over late November through the end of the year, millions of fitbits note that their human isn’t moving as much as usual. The devices don’t have long to wait—January is right around the corner and they get put back to use with gusto.



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