Effects of work demands on immunoglobulin A and cortisol in air traffic controllers

The professional activity of air traffic controllers (ATC) is often considered to be rather stressful. Certain characteristics of this job are likely to produce stress; for example an ATC can not predict when a situation becomes critical and he is not able to regulate the workload. In order to assess psychophysiological stress reactions in this working situation, saliva samples were taken from 158 male air traffic controllers before and after each of two working sessions. In contrast to the expected immunosuppressive effects, the working sessions caused a marked increase in the concentration and secretion rate of salivary immunoglobulin A (sIgA), as well as in the concentration of salivary cortisol. The increase in sIgA, however, was not correlated with the salivary cortisol response or with the amount of actual or perceived workload, whereas the cortisol response was correlated with both workload measures. It is suggested that positive emotional engagement is responsible for the observed sIgA increase and that measuring this physiological response may be a valuable tool for differentiating between positive and negative stress effects or between successful and unsuccessful adaptation or coping with situational demands.