Does sleeping heart rate correspond to health?

I’ve been tracking my sleeping heart rate using my Apple Watch for a long time, and recently noticed that my averages have been climbing. Am I coming down with something? Is it seasonal? Measurement error? Something else?

Although I’m comfortable writing my own software for the analysis, I don’t know enough about how to correct statistically for a time series like this. Anybody have some hints for me on how to get started?


Richard, have you changed your ambient temperature regime for sleeping? E.g., by running the heat or piling on blankets more since early December? (Just like with cricket chirps, our resting heart rates tend to track with temperature).

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Interesting…that’s possible. A few months ago I discovered that our (old) thermostat displays a temperature that’s several degrees higher than actual, so I adjusted it to make up for the difference. Let me see if I can do some more measurements to compare, especially versus nights when I’m in hotel rooms or elsewhere.


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I wish I had more experience with stats – in general! I guess my simplistic approach would be to try binning data in time periods and see whether one time period is significantly different from another?

Another thing I’ve tried is just randomly generating data, seeing if I see similar pattern. My hunch is that an upswing (or downswing) like this is a common artifact. (The low around early December seems more significant?)

That’s a really interesting question and one that would be of interest to me too! Many of us have large collections of passively collected data and would be interested in meaningful time series analyses to see if there’s any patterns/clusters in it!


I like this project too, but do not have an answer for the change. I was also thinking what I could do to enhance my understanding of my sleep data by fitbit. I don’t know how to get data like this from fitbit. I also have sleep data from my android phone. I wonder if it is possible to look at correlations. Any suggestions for data extraction?

@sprague Did you find the Apple watch better for tracking resting heart rate than other tools, or is this just what you happened to have?

Is the sleep data in Android stored in Google Fit or in a different vault? Asking as Open Humans already has an integration to export data from Google Fit!

Apple Watch is what I happened to have – after reading up on alternatives. @mike_lustgarten (twitter) swears by WHOOP, but afaik they don’t sell them unbundled.

I’d like to do a resting heart rate experiment. I think I have a very old Polar strap around here somewhere…