Calculating HRV values

The first thing that you need to know is that HRV analysis is only relevant if done on a rest or during a sleep record. fact, based on the literature, HRV values can only be accurately and meaningfully measured during a period with very minimal activity and movement. Indeed, it was reported that activity and movement can cause outliers in the ECG signal and then bias the HRV calculation and interpretation (please refer to the attached document Hexoskin-MeasureHRV). 

If you still want to perform HRV analysis during an activity or a wake period, you will need to download your data under Binary format and do your analysis by eliminating the outliers in the ECG signal. The HRV analysis can be performed with Kubios software (for more details, please refer to this link).

To do this, you need to:

1. Download Kubios software (free version)

2. Download the HxConvertSourceFile software*

3. Download the data of your choice

4. Make sure that you check the following boxes when you download and convert your CSV data:

5. Open Kubios software

6. Click File, then Open and then choose file "RR_interval.txt" of your choosing

7. For the data analysis and interpretation, please refer to the Kubios User's Guide.

*Note: If you are downloading your data (binary format) from the Hexoskin Dashboard, please know that the RR-interval time unit will be in s/256 (i.e. 256 lines of data will be the equivalent of 1 second). To perform HRV analysis in Kubios, you NEED to convert manually the time unit from s/256 to s, as Kubios only supports the time format in seconds (s) or milliseconds (ms). If you don't want to do the conversion manually, please use HxConvertSourceFile. This software will automatically download your .csv files in the proper RR_interval time unit (i.e. in seconds instead of s/256) and it will provide you with your data in .txt format (supported by Kubios software). 

             

Finally, as your HRV analysis is being performed on an "active" period, we strongly recommend only using the HRV metrics calculated by the time-domain analysis as they are the least sensitive to changes in the activity intensity.

Keywords: data analysis, heart rate variability, data export, conversion, cardiac analysis, biofeedback, hxconvertsourcefile, hxconvert, source, file, nn interval, Stress, RMSSD, R-R Interval, R/R Interval, N-N Interval, N/N Interval