Dynamic systems modeling of cortisol stress response

This paper presents preliminary results for using dynamic systems models to describe cortisol responses to stressful events. Linear, single-input single-output discrete-time models are used. Choices that must be made regarding interpolation and input modeling are discussed in some detail. Results are presented that indicate an impulse model for the stressful input gives a better fit than no input, and that logarithmic transformation of the data before model fitting gives no better results than using the raw data. The issue of stability of the resulting models is discussed. In addition, the paper discusses how the resulting dynamic systems models can be used for statistical analysis, as well as for predicting future stress responses.Copyright © 2008 by ASME