Beat-to-beat blood-pressure measurements applied in studies on mental workload

Heart rate variability diminishes during mental task performance. This decrease can be related to a change in control of the autonomic nervous system of blood pressure. This change in sympathetic/parasympathetic balance might be caused by a decrease in baroreflex sensitivity. - To study the characteristics of the baroreflex, blood pressure has to be assessed beat-to-beat. Continuously monitored blood pressure can provide the beat-to-beat values for computing spectral measures of blood pressure, and the baroreflex sensitivity. - The objective of this paper is to show that the effects of mental workload on blood pressure in a series of experiments are very consistent, although different methods were used to measure blood pressure continuously (Intra-arterial, FIN.A.PRES model 3 and 5, Ohmeda 2300). We selected one or two similar tasks from four experiments with small differences in task characteristics. - The cardiovascular effects of mental workload are characterized by a decrease in inter-brat interval, heart rate variability, blood pressure variability, and baroreflex sensitivity, and an increase of blood pressure. The blood pressure increase and the BRS decrease was larger for the more effortful tasks within the experiments. These effects are found in spite of the different methods of blood pressure measurements. - We conclude that the FIN.A.PRES devices are very well applicable in our research, where rest-task comparisons play a major role. The task effects in intra-arterially measured blood pressure are very well reproduced by FIN.A.PRES models.