I am quite enthusiastic about wearables and the idea of the quantified self (QS) in general. I have done a number of previous posts on this topic.
A little over a year ago I resolved to try to make good use of these, both to collect some interesting data as well as to try to use it to get healthier. I religiously used a Garmin Forerunner when I went running and tried to couple it with some measurements of my respiratory peak flow using a peak flow meter. I did this routinely for about half a year. Altogether, I exercised about a third of the days in this interval, mostly running but also swimming. The Garmin, of course, gives one quite a lot of information and I spent some time after this mulling over the data, trying to find some useful numbers to correlate and tabulate.
What I eventually came up with is shown in the linked gsheet. The most useful number that I could find related to my athletic performance was my maximum heart rate. I usually do not run the same course each time since I find that rather boring so it is hard to directly compare times but I do try to do little mini sprints within my run and tabulated the maximum heart rate from these sprints each time I went running. I hoped that by tabulating these and pushing myself I would go faster but as seen by the tabulations this did not happen!
My next idea was that if I coupled my peak flow readings to these maximum heart rate readings I would see a correlation of days when I had a higher maximum heart rate, perhaps I had better respiratory function. (I should mention that I suffer from a mild case of asthma.) Unfortunately I was not able to do this coupling as well as I wanted as carrying around the peak flow meter is a bit tricky and I only obtained a few readings. Overall these did not reveal any correlation. But again, I tried and it is kind of interesting to see the results.
Finally, I should point out that I am quite interested in data privacy and I did not want to actually put up my own, precise values for heart rate or peak flow -- just because I think they characterize me too much. So what I actually put up what I call "corrected numbers," which are deliberately adjusted in a way that does not give you the exact values but essentially shows the trend and correlation in the data. If people have any ideas about how to get the exact numbers I would be interested although I doubt anyone has that much motivation to do this.
Public archive of gsheet:
http://archive.gersteinlab.org/public-docs/2015/12.31/Max-HR-and-PF-in-2nd-half-2014.xlsx
Private mail archive:
https://mail.google.com/mail/u/0/#search/QS-iday-analysis-of-2014