NEUROENDOCRINE RESPONSES TO REAL AND SIMULATED BA-HAWK MK-51 FLIGHT

The effects of psychological workload on the plasma levels of eight ne uroendocrine hormones were studied In 5 undergraduate and 5 senior mil itary pilots of the Finnish Air Force (FAF). All subjects performed th e same short-term basic flight mission, which included the following: 1) start; 2) ILS-approach in minimum weather conditions; 3) visual app roach; and 4) landing. The mission was performed twice: first with the BA Hawk MK 51 simulator with minimal G-forces and after that with a B A Hawk MK 51 jet trainer with or-forces below +2. Blood samples were c ollected 30 min before and 10 min after the mission and were measured for adrenaline, noradrenaline, ACTH, beta-endorphin, prolactin, vasopr essin (AVP), atrial natriuretic peptide (ANP), and cortisol. The plasm a levels of adrenaline, noradrenaline, ACTH, beta-endorphin, and corti sol did not change significantly in response to simulated or real flig ht. plasma prolactin levels increased significantly (p = 0.037) in all subjects after the mission performed with jet trainer, and the increa se was especially great in cadets. However, the same mission performed with the simulator did not raise plasma prolactin levels. This findin g suggests that the psychological workload in a flight simulator does not correspond to the psychological workload in a real jet trainer, at least not In basic flying. Plasma AVP increased significantly (p = 0. 032) after the mission performed with the simulator in cadets; this in crease can be described as a ''first-time effect.'' plasma ANP also in creased significantly (p < 0.05) after a real jet trainer flight. ANP generally maintains the electrolyte and welter balance, but it is poss ible-that elevated plasma ANP levels during a military fright are due to an increased workload of the heart and sympathetic stimuli. because the psychological workload of the flight missions was not extreme, ba sic military flying had no effect on the usual stress hormones such as ACTH, beta-endorphin, and cortisol in this study. Certain hormones, e specially prolactin, and to a lesser degree ANP and AVP, appear to be sensitive to psychological workload.