ABSTRACT
Mental workload assessment using heart rate can be improved with an autonomic space model of sympathetic and parasympathetic nervous system influences on the heart. Principal components analysis of multiple psychophysiological measures of cardiovascular activity was used to derive the underlying sympathetic and parasympathetic information needed to represent the autonomic space for the heart. This method was applied to cardiac data that were previously collected during a fullmission flight simulation. Volunteer commercial pilots flew missions simulating normal flight and a high workload flight in poor weather with an inoperative autopilot, an engine stall, the loss of one hydraulic system, and other distractors. The autonomic components complemented the heart rate and heart rate variability data and increased the number of mission phases that could be differentiated from each other. Further, the autonomic components indicated that heart rate was faster during the high than low workload mission because of increased sympathetic activation.
