Elevated peripheral adrenaline levels may be part of two different reaction patterns that have quite different psychological or emotional connotations. The physiological function of the sympathoadrenal reaction is always the same: It plays a role in the mobilization of resources. But, depending on the psychophysiological state of the subject and the stringency of the situational demands requiring state changes, such mobilization may have very different meanings. Challenging situations demand an active mental involvement of the subject that provokes the adrenaline reaction. It becomes less pronounced or even fades away when such (same or similar) situations are repeated, provided they were mastered successfully in the past. In the studies by Ursin, Baade, and Levine ( 1978) the repetition of a parachute jump, after a first successful jump, provoked less pronounced adrenergic reactions. In our data from the driving examiner study, a similar phenomenon was found. Without further complications, the elevation of adrenaline rates may be interpreted, on the psychological level, as an indicator of effort without distress ( Frankenhaeuser, 1989). On the subjective level, such elevations are accompanied by feelings of (positive) activation.
However, when subjects are forced to compensate for their apparently inadequate state in the confrontation with situational demands the elevation of peripheral adrenaline rates is embedded in a syndrome that is stressful. In such cases, the elevation of adrenaline rates is accompanied by feelings of tension and anxiety. The important thing for theories on work and health is that such compensatory mechanisms may be mobilized more or less chronically during work, depending on the general condition of health and wellbeing of the subject. Ursin ( 1980, 1988) pointed to the adverse effects of such sustained (sympathetic) activation. Our data suggest that such a phenomenon might apply in regular working situations.
In this chapter, we have identified the effects of working conditions on the psychophysiological state of the worker. The load of the work and its associated health effects can only be determined by recording psychophysiological measures in addition to performance and subjective measures. We found two major effects of work: one related to the cognitive complexity of the task (computational effort), the other to effects of the working conditions on the state of the worker (compensatory effort). With respect to the first type of effort, some scientists have complained ( Luczak, 1987; see also Manzey, 1998) that HR and HRV are not diagnostic enough since they fail to distinguish between cognitive and emotional load. We believe that such a distinction is completely artificial. Cognitive and emotional systems are closely coupled in the brain and, as a consequence, the distinction between cognition and emotion is a typical example of a "Descartes type of error" ( Damasio, 1994).