Mental stress causes a physiological response and is often assessed by heart rate variability. In this work, we investigated cardiovascular parameters other than heart rate variability.
We performed a stress test with 44 healthy volunteers and evaluated 17 cardiovascular parameters measured with a CNSystems Task Force Monitor, several self-reported measures as well as cortisol and alpha amylase concentrations from saliva samples. By statistical testing we determined the cardiovascular parameters that exhibited the clearest response to the stress test. In addition, we attempted the classification of cardiac cycle states using a random forest classifier that was evaluated with Cohen's kappa κ in a leave-one-subject-out cross-validation.
From the cardiovascular parameters, heart rate, cardiac output, cardiac index, mean blood pressure, and left ventricular work index yielded significant results. Cardiac cycle state classification reached κ = 0.58. While the self-reported measures showed clear stress responses, salivary cortisol and alpha amylase concentrations remained mostly unaffected.
The presented study provides insights into the physiological response to mental stress. We identified the parameters that showed a clear stress response, with the strongest effect found for the elevated left ventricular work index.