QS Access to heart rate data on IOS. What am I seeing here?

I failed to set up notifications for heart rate events in the Apple Health App. A heart rate event is normally a heart rate exceeding some value for ten minutes. A cursory examination of my heart rate data looks like I am enjoying some tachycardia. I used QS access to download heart rate data. The app says I can have hourly or daily data. I chose hourly. The column heading says Heart Rate (counts/minute) which makes sense, but what does the number in the cell mean when the period is an hour? Does the number represent the maximum, minimum, average, mode, or something else?

Is there any way to use the app to get all the data collected so I can ferret out my own list of events?

My understanding is that the heart beats are treated as a rate (counts/minute), so the number represents the average for the hour.

Regarding the second question, is it individual “heart beats” that you want?

Steven, Thanks for the feedback. A while ago I asked myself the following question. If a person’s heart did not beat for 30 seconds and then beat every half second for the next 30 seconds (for a total of 60 beats the second half of a minute) what it the heart rate? Well, there were 60 beats in that minute, but I am not happy with that answer because if their heart only beats half the time and is tachycardic the other half something is seriously wrong and the average hides it.

In my case, I would like to get the date and time of every beat, but I will take what I can get, because I recently discovered I have periods of tachycardia. The watch has been recording my pulse rate more often than anything else and I hoped to get a look at the data to see if with more data I could help my doctor figure out how serious if it is at all serious this may be. Most devices only record for 24 hours. The best data so far is from a Zio patch that records for two weeks.

i.e. “RR intervals”

I don’t think Apple Health captures that level of detail; maybe one data point every few minutes?

The Apple Watch does let you record short ECGs, which can be exported as a PDF (to show a doctor), or as CSV (with the raw data).

Eric,

I appreciate your efforts to help but it seems you are doing a lot of guessing here. I didn’t want HRV (R-R) data. I am looking for tachycardia which is the number of beats per minute over 100 although people generally set their own threshold which is allowed with the Apple Watch. I need to know when it goes over the threshold I chose and for how long it continues above the threshold. This is what heart rate data looks like, It is collected much more frequently than you thought it was.:

HKQuantityTypeIdentifierHeartRate Apple Watch … 2018-12-05 07:50:12 -0400 2018-12-05 07:48:15 -0400 2018-12-05 07:48:15 -0400 51
HKQuantityTypeIdentifierHeartRate Apple Watch … 2018-12-05 07:58:08 -0400 2018-12-05 07:49:55 -0400 2018-12-05 07:49:55 -0400 52
HKQuantityTypeIdentifierHeartRate Apple Watch … 2018-12-05 08:00:01 -0400 2018-12-05 07:54:25 -0400 2018-12-05 07:54:25 -0400 56
HKQuantityTypeIdentifierHeartRate Apple Watch … 2018-12-05 08:04:37 -0400 2018-12-05 07:59:35 -0400 2018-12-05 07:59:35 -0400 54
HKQuantityTypeIdentifierHeartRate Apple Watch … 2018-12-05 08:10:30 -0400 2018-12-05 08:06:26 -0400 2018-12-05 08:06:26 -0400 52
HKQuantityTypeIdentifierHeartRate Apple Watch … 2018-12-05 08:14:47 -0400 2018-12-05 08:10:17 -0400 2018-12-05 08:10:17 -0400 52
HKQuantityTypeIdentifierHeartRate Apple Watch … 2018-12-05 08:36:16 -0400 2018-12-05 08:36:11 -0400 2018-12-05 08:36:11 -0400 83

HRV (R-R) data looks like this and is collected with millisecond resolution.
HKQuantityTypeIdentifierHeartRateVariabilitySDNN … 2018-10-05 16:11:17 -0400 8.82468
HKQuantityTypeIdentifierHeartRateVariabilitySDNN … 2018-10-05 20:40:11 -0400 14.1995
HKQuantityTypeIdentifierHeartRateVariabilitySDNN … 2018-10-05 23:53:32 -0400 11.5271

R-R data can be used to calculate various HRV-related metrics, but would also give you “the date and time of every beat”. Unfortunately you don’t get that data from the Apple Watch, so the point is moot…

Did you have any episodes of tachycardia while wearing the Zio patch? If not, you could do a short ECG recording with the Apple Watch when you sense an episode, and show that to your doctor.

As your sample data appears to confirm, heart rate is sampled only every few minutes (outside of workouts)?

Would definitely be nice if the QS Access app had an option to export data without aggregating it first.

Your comment, “Would definitely be nice if the QS Access app had an option to export data without aggregating it first.”

Exactly. There are two problems with the way it is aggregated. First, we don’t know how it was done and second I can’t see what application the number presented has.

I had lots of episodes with the Zio patch. that was how I found out I had tachycardia.

I rely on a chest strap to gather every beat but there are practical limits to collecting that data. I haven’t looked to see what QS does with it perhaps I should but I have the dismal feeling it is going to be presented in aggregate.

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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.

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"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 have exported my data as a zip file and I find the two XML files but in order to get the csv files one needs to use third party softare to extract it from the zip file.

‘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.’

Basically: tach·y·car·di·a, noun, an abnormally rapid heart rate.

More specifically: Tachycardia is a condition that makes your heart beat more than 100 times per minute.

However, elsewhere I have read that it only counts as a problem with reading where the heart rate is over 100 for ten minutes which I believe is the standard by which Apple presents you with a ‘Heart Rate Notification’.

Readings that don’t last for more than 10 minutes are available if the watch is reading for 2 to 12 minutes haphazardly.

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I am a new user of QS Access (evidently vers 1.3), examining heart rates for a particular tachycardia. I am frustrated since the timestamps in the CSV exports appear to repeat, as in the sequence

10/05/19 03:48:00 PM 10/05/19 03:48:00 PM 64
10/05/19 04:36:00 PM 10/05/19 04:36:00 PM 78
10/05/19 04:36:00 PM 10/05/19 04:36:00 PM 84
10/05/19 04:36:00 PM 10/05/19 04:36:00 PM 84
10/05/19 04:36:00 PM 10/05/19 04:36:00 PM 84
10/05/19 04:36:00 PM 10/05/19 04:36:00 PM 85
10/05/19 04:36:00 PM 10/05/19 04:36:00 PM 88

This makes it very difficult to track the duration of episodes. I would very much like to track heart rate at the same granularity at which beats/minute are acquired, evidently varying over ranges of 2 to tens of minutes.

From the above it appears my best best is to (i) extract the .xml file, (ii) grab the lines with HKQuantityTypeIdentifierHeartRate Apple Watch and save THESE as an .xml, and then process this into a .csv file. Does this seem reasonable?

Thanks to all!