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Updated: Jun 18, 2026
Software for Analysis of Heart Rate and Blood Pressure Time-series Data from the Valsalva Maneuver
Published on: June 27, 2025
A MATLAB toolbox for correcting within-individual effects of respiration rate and tidal volume on respiratory sinus
Stefan M Schulz1, Erica Ayala, Bernhard Dahme
1University of Würzburg, Würzburg, Germany. schulz@psychologie.uni-wuerzburg.de
Abstract:
Respiratory sinus arrhythmia (RSA) is a common estimator of vagal outflow to the heart, dependent on parasympathetic activity. During variable breathing, both respiration rate and tidal volume contribute substantially to within-individual RSA variance. A respiratory control method allows for within-individual correction of the time-domain index of RSA. rsaToolbox is a set of MATLAB programs for scoring respiration-corrected RSA using measurements of cardiac interbeat intervals, respiratory-cycle times, and tidal volumes, recorded at different paced-breathing frequencies. The within-individual regression of RSA divided by tidal volume upon total respiratory cycle time is then used to estimate the baseline vagal tone for each breath of a given total respiratory-cycle time. During a subsequent analysis, the difference between the observed RSA (divided by the tidal volume at each breath) and the RSA divided by the tidal volume that was predicted by the baseline equation serves as an estimate of changes in vagal tone. rsaToolbox includes a graphical user interface for intuitive handling. Modular implementation of the algorithm also allows for flexible integration within other analytic strategies or for batch processing.
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