Release notes

Version 3.3.1 (released 23.8.2019)

The following changes and bug fixes have been implemented (*indicates features available only in the Premium version):

  • Minor updates to FIT file support, including corrected conversion of FIT Laps to Kubios HRV event markers (Kubios HRV markers are now triggered by lap end times, instead of lap start times).
  • Fixed a bug in EDF file support, which caused Kubios HRV not to be able to open EDF files that include empty channel label(s). Channels with an empty label (if any) are now named as “No_label_xx”.*
  • Corrected scaling of cumulative EE and TRIMP values for different analysis window lengths.*
  • Fixed a bug, which caused repetition of last analysis sample’s MSE values on text file export.*
  • Corrected a bug, which caused Kubios HRV to crash when using custom threshold in artifact correction.
Version 3.3.0 (released 7.6.2019)

Compared to previous release, the following features, changes and bug fixes have been implemented (*indicates features available only in the Premium version):

  • Instantaneous energy expenditure (EE, kcal/min) estimate based on beat-to-beat HR is now included in Kubios HRV Premium. This activity related EE is computed using Keytel’s equation, and both instantaneous and cumulative EE are included in time-varying HRV results. Diet induced thermogenesis (DIT) is not anymore separated from activity related EE, because this cannot be reliable reflected to instantaneous EE without details of dietary schedule.*
  • Banister’s Training Impulse (TRIMP) computation was added to Kubios HRV Premium. TRIMP is computed according to the exponential model proposed by Morton et al. 1995 (see details). TRIMP accumulation rate increases exponentially as a function of exercise intensity, modelling lactate accumulation during exercise. In Kubios HRV, we compute the TRIMP using beat-to-beat HR values, and thus, instantaneous value of TRIMP (TRIMP/min) can be reliably derived and used to assess training intensity. A single number describing the training load is obtained by summing the TRIMP/min over the entire training session duration. The TRIMP/min and cumulative TRIMP values computed in Kubios HRV are linked to training intensity and training load as shown below.
  • Visualisation of instantaneous (time-varying) HRV parameters was modified on the time-varying analysis tab on user interface and also on the time-varying report sheet. Instantaneous activity level information (based on HR zones) was added to time-varying report page.*
  • Polar Flow authorisation and FIT file export updated. Fixed a bug that prevented exporting training data from Polar Flow if the user had manually deleted an exercise from Polar Flow.*
  • Support for Bittium Faros (a lightweight ECG device) event markers was added. The event marker data available in the EDF-files recorded with a Bittium Faros ECG sensor is now correctly imported into Kubios HRV Premium, enabling the user to use the marker data while performing HRV analyses.*
  • Added missing EDF+C file format to supported file type in Kubios HRV Premium.*
  • Added support for string event markers. Laps in FIT format files are now converted to event markers and are visualised in user interface. The Lap markers in FIT files are grouped to manual laps and time, distance, etc. based laps.
  • Event marker visualisation in user interface was modified. Event markers are now shown as down pointing triangles on top of ECG and RR axes, and marker positions are show in RR and ECG axes as dotted lines (which can be toggled on/off). A mouse-over feature for markers was added for displaying the marker annotation.
  • Added snapping to event markers when moving or resizing analysis samples. This feature will enable easy positioning of analysis samples according to event markers (e.g. start/end the analysis sample at certain event marker times).
  • Added “All Supported Files” in the file filter (this is also used as the default value for the file filter). This reduces the need to change the file filter in file open dialog and makes opening of data files more straightforward.
  • Added a “Launcher” window providing easy access to HRV data, Tools (Polar Flow Export*), and Kubios HRV support material.
  • Improved support for multiple monitors.
  • Several minor improvements in user interface layout and software performance.
Version 3.2.0 (released 21.1.2019)

Compared to previous release, the following features, changes and bug fixes have been implemented (*indicates features available only in the Premium version):

  • Export training data from your Polar Flow account directly from Kubios HRV Premium in FIT format. Note that the files include beat-to-beat data (RR or IBI data) required for HRV analysis only when a Polar Flow compatible device with H6, H7 or H10 heart rate sensor is used for the measurement.*
  • Automatic sample generation based on sample specifications given at predefined CSV file (“Kubios_Samples.csv”). This file must be found from the same folder as the data files to be analysed. In the CSV file, 1) sample label and color, 2) sample start time, and 3) sample end time can be defined for as many samples as needed. The sample definitions can be made file-by-file or to apply all files found in the specific folder.
  • Analysis samples can now be also manually named (Sample Label field) and color-coded (Sample Color field). Sample labels and colors are visible in the user interface and on the reports.
  • PNS and SNS index computations modified and graphs improved in the software GUI and Report page. In the computation of these indexes, LF and HF powers in normalised units were replaced with normalised standard deviations of the Poincare plot, i.e. with SD2 (%) and SD1 (%), because these nonlinear parameters provide a more robust estimate of sympathovagal balance especially in cases of slow breathing. For details see
  • Energy expenditure computation was corrected and modified, now including also an estimate of the Diet Induced Thermogenesis (DIT), which is the energy expenditure related to digestion of food and is estimated to be 10% of total energy expenditure within 24 hours. In addition, in ver. 3.1 the BMR was erroneously added to the total energy expenditure, which caused the energy expenditure estimates to be unrealistically high. This has been now corrected and the total energy expenditure is now divided into three components: 1) Basal metabolic rate – BMR (Mifflin St Jeor equation), 2) Diet Induced Thermogenesis – DIT (10% of energy expenditure), and 3) Activity related energy expenditure (Keytel equation).
  • Artefact correction user interface implementation improved. The applied correction method (default: “Automatic correction” in Premium and “none” in Standard ) and acceptance threshold for artefact percent (default: 5%) can be now defined in preferences. In user interface, artefact percent is displayed for the whole measurement as well as for the analysis samples separately. Analysis samples with low data quality (Artefact percent > defined threshold) are indicated in user interface and in reports.
  • New mouse shortcuts added to RR and ECG data views for improved usability. The new mouse shortcuts are
    • Pan (scroll, SHIFT + scroll) and zoom (CTRL + scroll) data using mouse scroll wheel.
    • Add a new analysis sample (right mouse button + drag) and delete sample (CTRL + right mouse button).
    • Center ECG data view to current cursor position in RR data view (CTRL + left mouse click).
    • Pan both RR and ECG data views by dragging with middle mouse button.
  • Personal details (Name, Gender, Age, Max HR, Height, Weight and BMI) are now included on report figures and report figure layout overall modified. For example time ticks readability was improved and ranges of HR, Stress and RMSSD zones were added.
  • Several minor improvements in user interface layout and software performance.
Version 3.1.0 (released 19.3.2018)

This is the first major update since the Kubios HRV Standard and Premium versions were launched. Compared to previous release, the following features, changes and bug fixes have been implemented (*indicates features available only in the Premium version):

  • Support for PPG (pulse wave) data and a pulse wave detector algorithm added. Supported PPG devices include at least Empatica E4, Shimmer and Biopac PPG devices.*
  • Comparison of Mean RR, Mean HR, RMSSD, LF power n.u., and HF power n.u to normal resting values as published in Nunan et al. 2010.
  • Stress index parameter according to Baevsky’s stress index added to analysis parameters.
  • New parasympathetic nervous system (PNS) and sympathetic nervous system (SNS) indexes proposed. PNS index is based on Mean RR, RMSSD and HF power (n.u.), and LF index on Mean HR, Stress index and LF power (n.u.) values as compared to normal resting values.
  • Energy expenditure estimation added including basal metabolic rate (BMR) according to Mifflin-St Jeor formula and activity related energy consumption based on Keytel’s model.
  • New Results Overview tab added to user interface, which illustrates the HRV parameter comparisons to normal resting values; time trends for Mean HR, RMSSD and stress index; HR and stress zones as well as estimated energy expenditure.
  • New preference option for nonlinear analysis added, which enables you to force nonlinear analysis to use non-detrended RR interval data.
  • Time-varying analysis functionality changed. The analysis can be performed either for the whole measurement or for the selected analysis samples (default=whole measurement).*
  • Time-varying estimation of Stress index, PNS index and SNS index (these parameters are also included in exported result files).*
  • Standard HRV analysis report sheet updated, now including results overview (comparison to normal values and PNS/SNS indexes) for every selected analysis segment.
  • Time-varying analysis report sheet updated, including a detailed illustrations of HRV parameter time trends, PNS and SNS index time trends, and HR, Stress and RMSSD zones as well as energy expenditure. Optional time-domain, frequency-domain and nonlinear parameters shown in the report can be modified from Preferences.*
  • New option added for beat detection editing. Using the Remove several option, all beat detections after or before the current beat; or beat within a given time interval can be removed. This feature is designed to easily remove faulty beat detections that occur when ECG data is not available (e.g. if the ECG device is turned on before attaching the electrodes or turned off after detaching the electrodes).*
  • License information and maintenance status added under Help uimenu.
  • Performance improvements on analysis parameter computations.
  • Interpolation method of the long segments without data (>5sec) is changed to linear.
  • ECG derived respiration (EDR) estimation algorithm improved.*
  • Added support for opening Bittium Faros sensor’s HRV channel.*
  • STD HR parameter computation modified.
  • Added Artifacts (%) into time-varying results (mat and txt exports).*
Version 3.0.2 (released 23.6.2017)

Compared to previous release, the following features, changes and bug fixes have been implemented (*indicates features available only in the Premium version):

  • A new colormap (“Fire”) added to RR interval spectrogram under time-varying analysis options*
  • ECG derived respiration (EDR) was added into time-varying analysis results (i.e. now shown in the Time-Varying results tab on the GUI and exported to .TXT and .MAT results file)*
  • Manually fixed scaling for RR histogram also scales the Poincare plot data axis when detrending is not applied. When RR data is detrended the scale of Poincare plot is automatically adjusted to fit the detrended zero mean data values
  • Direct link to User’s Guide was added into the Help uimenu
  • Text file support updated to ignore empty values
  • FIT file support updated to correspond the latest specifications (2.35)
  • Performance improvements for time-varying analysis results updating and Zephyr ECG file reading*
  • Print dialog updated
Version 3.0.1 (released 27.4.2017)

Along this release, Kubios HRV Standard and Premium are available also for Linux operating systems. Compared to previous release, the following features, changes and bug fixes have been implemented (*indicates features available only in the Premium version):

  • Kubios HRV is now available also for Linux
  • Support for ECG data stored in Cardiology XML file format was added*
  • RR and ECG* text file importing was updated to support double-byte unicode files
  • QRS detection algorithm functionality was improved*
  • Kubios MAT file export was updated (the MAT file includes original data and all pre-processing steps as well as analysis settings are stored in this file, and, thus the MAT file can be used to fully store the analysis session)*
  • Kubios HRV version 2.2 color theme can now be selected from the software preferences to make Kubios more user friendly for people suffering red-green color blindness
  • Mean HR parameter computation fixed
  • Font visibility problem fixed
Version 3.0.0 (released 27.1.2017)

This was the first commercial release of Kubios HRV, launching of Kubios HRV Standard and Kubios HRV Premium versions. Compared to the previous release (ver. 2.2), the main new features of version 3.0 were (*indicates features available only in the Premium version):

  • Data support: 1) Polar IBI file support updated; 2) Custom ASCII file import support updated; 2*) ActiHeart and ActiWave Cardio data support added; 3*) Zephyr BioHarness data support added; 4*) annotations support for EDF+ files updated.
  • Pre-processing: 1*) An automatic RR artefact correction method was added. The new method provides enhanced artefact and ectopic beat detection performance and does not require a manual selection of optimal threshold value.
  • Time-domain HRV parameters: 1) Computation of minimum and maximum HR as average of 5 beats (default value, can be changed in preferences) was added; 2) NN50 and pNN50 parameters renamed as NNxx and pNNxx (default threshold is 50 ms, can be changed in preferences).
  • Frequency-domain HRV parameters: 1*) Lomb-Scargle periodogram was added as an alternative for Welch’s periodogram (selection can be made in preferences); 2) VLF, LF and HF band powers are now given also in natural logarithm scale; 3*) warning given if ECG derived respiration is outside the defined HF band.
  • Nonlinear HRV parameters: 1) Poincaré plot ratio SD2/SD1 was added.
  • Time-varying analysis*: Time-varying analysis methods added to HRV Premium. These methods include time trends for time-domain and frequency-domain parameters as well as for a limited number of nonlinear analysis parameters. Changes in time-frequency information of HRV data are assessed by spectrogram and a parametric Kalman smoother based time-varying spectrum estimate.
  • Reports and results export: 1*) ”SPSS friendly” batch file export was added; 2) Time-varying analysis results added to HRV report (additional page included); 3) Handling of report figures was updated (HRV Report and *ECG print). All report pages open in the same window, where the user can view the report pages, print selected pages or save pages to PDF file.
  • GUI and usability: 1) Visual layout of the software was changed; 2) HR (instead of RR) data visualisation can be selected in the GUI. In addition, several usability modifications to improve user experience.