This is kind of related, because I want to do a similar download of what I would call instantaneous heart rate. I have been "exporting" apple watch heart rate data through the extremely cumbersome process Apple allows (in Health Data, click person icon in upper right, export health data, then either save or email the data through a ZIP file which contains 2 extremely large xml files, and a surprisingly simple CSV file for each ECG recording).
I just downloaded the QS Access App - and am getting frustrated, because I cannot seem to allow it to see or use heart rate data, so I don't know if I'm missing something simple and obvious. Other apps see "heart rate", but QS Access only sees "Active Energy"
However, with regards to what Douglas wants, what I have learned from my exports and other internet sources is that under normal conditions, the Apple Watch uses the green light and sensor on the back of the watch to monitor pulse rate, kind of similar to the way the red&IR lights do on a pulse oximeter. This does a "spot check" of pulse rate roughly every 2-12 minutes. I find no rhyme or reason to how often it does the check.
However, if you start the "workout" app (I start the non-specific "Other - Open Goal"), the Watch will continuously use the green light to record pulse rate. It is also a little sporadic, giving readings once every 1-10 seconds, but is pretty close to a continuous reading of heart rate in beats per minute. It is possible (pure speculation) that it only reports a new heart rate when it detects a change from the previous rate. But for Douglas, I expect that it would show your tachycardic events nicely.
So now, back to QS Access - I would like to see an App that exports "every" HR event, not an average by any more coarse time scale. I have looked slightly at the Python code listed at http://www.markwk.com/data-analysis-for-apple-health.html which is where I learned about "QS Access." I don't know if there is any connection between the python code and QS Access. As a Biomedical Engineer, I have dealt with lots of HR data and programmed in many languages, but I feel the Python method is way to complicated for most people, I think they just want a simple way to view their data (HR in this case).
A couple of additional comments about the Apple Watch data:
- when the watch interrupts you to remind you to "breathe" it actually records heart data (using the same green light) a little differently - in this case it records the heart's R-R intervals for that 1 minute period. In reality, RR=60/HR or HR=60/RR, so they are really just different ways of expressing the same information. The difference is that "breathe" gives the RR between each beat, whereas the "workout" does some type of very short average. Instantaneous HR is simply 60/RR between each beat.
- finally, the green light pulse method uses only one arm, whereas the ECG recording uses both arms and the ingenious method of picking up the electrical activity of the right-arm vs the left-arm by having the user touch the crown. Douglas, I have the "ECG" icon on my Apple Watch face, and within 3 seconds I can start an ECG recording. Then, using the very cumbersome "Export" in Health data, I can access the CSV files from each ECG. Excel doesn't automatically do any analysis, but it is simple to open the file and display of graph of the ECG. To get a clean ECG recording, it is important to minimize muscle and movement artifact, most easily done by resting your arms on lap or table, and touching the crown very gently but definitely. I doesn't hurt to lick your finger, which gives better electrical contact compared to a very dry finger. The ECG feature is not available on older Apple Watches.
My sense is that there a void in terms of what Apps are available for heart rate on the Apple Watch. I am interested in what QS Access can do to help me, if I can solve why I cannot access the heart rate data.