I've noticed an interesting pattern in my Garmin overnight heart rate variability the last two months. It seems the same decline-slight increase-decline-rise back to the starting level pattern repeated almost exactly, with a repetition interval—a period, if you will—of right about four weeks. That's interesting!
So I wanted to put this data in a spreadsheet with some other things I've been tracking to see if maybe some perceptible things have some phase relationship with this. Thing is, Garmin doesn't let you export that in CSV. You can, however, use the browser "developer tools" to find the JSON file with the data and download that. I have done a bit of this sort of thing before. Thing is, while I'm nerdy, I'm a biochemistry nerd, when I see JSON I wonder if this has something to do with the Golden Fleece.
So, anyway, to get this into a spreadsheet first step is to convert to CSV. I googled around and found that one can convert using a tool with the very unix name "jq." I mean, I don't know if you can or I can, but someone can. This is tool that I can tell you is not easy to use if you are still wondering where the Argonauts come in. None of the stuff I tried just copying and pasting would run at all. The man page, it's quite a thing. But I fiddled with it for like half an hour and came up with this:
jq -r '.hrvSummaries[] | [.calendarDate, .lastNightAvg, .weeklyAvg] | @csv '
So anyway, success, got it into my spreadsheet.
