Saturday, June 23, 2012


Record and Analyze HRV from 910XT

Enable RR recording

Turn on the FR910XT and go into the menu screen. Press UP then DOWN and repeat 10 times (if you count up-down as one cycle then this is 5 cycles).
You should now have entered the "diagnostic menu". From here select HRV on the top and press Enter. Now you can enable the hrv recording.

Getting RR values from FIT

For now I used fitdump and awk/sed to get rr values from the fit file into another file.

fitdump |grep -A1 hrv | grep time|awk '{print $4}'|sed 's/(\([0-9]*\)),/\1/g'

If there's values much too high you could filter them e.g.
awk '$1<1500'



You can use the hrv toolkit.
 plt_rrs -m -R hrv_values1

get_hrv -m -S -R 2012-06-24_08-08-32-80-97354.hrv

Or there is the HRV Analysis which is a windows application but works under wine:

Or for some less sophisticated plot try this, use the above output and filter again with awk:
awk ' { OFS="\t"}{total=total+$1; print total,$1}'  > hrv_values

gnuplot> plot "hrv_values" using 1:2 title 'HRV' with impulse


Lexel said...

Wow realy intresting !!! Thanks a lot
How did you find the trick to enter the diag menu ?

Java said...

Awesome trick to get into the Diag Menu!
By the way, the HRV Analysis soft is also available for Linux (natively, so... no longer need for WINE) @

Jason Titus said...

How exactly does enabling this impact the watch's performance? Obviously the downloaded data files will be larger, and thus take up more space. Are there other side-effects? Decreased battery performance for example? Cause some of the calculations to be different (like TSS perhaps)? Anything?


Andreas Loeffler said...

as I do not own this watch anymore I can't provide any figures but iirc the increase in fit filesize wasn't really significant, probably battery drains faster with this enabled.
The time I tried I only periodically checked hrv data as provided by the watch.
Btw. you can achieve similar thing (that is get an idea of your fitness/recovery level) by using your heart rate strap and connect some ant dongle to a (linux?) pc. the retrieved data can than be analyzed the same way.

Maurice said...

Hi, do you know the R-R sampling rate in Hz that the 910t has after enabling this feature?