NEUROENDOCRINE RESPONSES OF PLIGHT CADETS DURING MIDTERM TESTS AND OFFIGHTER PILOTS DURING TAIL CHASE SORTIES

Urinary excretion of catecholamines (CA), epinephrine (E), and norepin erphrine (NE) was determined in flight cadets (n = 46) during mid-term test sorties and was compared with the measures of these variables in fighter pilots (n = 65) during tail chase sorties. Flight cadets were divided into passed and failed cadets. Fighter pilots were divided in to superior, above average, and average with flying ratings of >7, 6-7 , and <6, respectively, and with flying experience of 2050 +/- 1081 h, 884 +/- 575 h, and 616 +/- 756 h, respectively. CA excretion data sho wed significant intra- and intergroup differences. Excretion rates for CA and NE before and after flight were significantly higher in flight cadets than in fighter pilots. After flight, all the preflight urinar y variables increased significantly in passed flight cadets, while cha nges in failed flight cadets were not significant. In all groups of fi ghter pilots, preflight excretion rates for CA, E, and NE rose postfli ght, but the differences within the groups were not significant. The N E/E ratio decreased significantly as a function of flight adaptation. The pre- and postflight NE/E ratios were lower in fighter pilots than in flight cadets. The Delta NE/E ratio de creased in fighter pilots, b ut increased In flight cadets. The preflight NE/E ratio was smaller fo r superior than for above average and average fighter pilots, and for passed than for failed flight cadets. The postflight NE/E ratio did no t show any significant differences within the groups. In superior figh ter pilots, the Delta NE/E ratio remained relatively stable, while it was reduced in above average and average fighter pilots. An unchanged or a reduced Gamma NE/E ratio can be regarded as rapid adaptation of s ympathoadrenal activity to flying stress. In passed flight cadets, Del ta NE/E ratio rose, indicating a flight-induced sympathoadrenal stimul ation. This can be interpreted as a prerequisite for flight adaptation during initial phase of flight training. On the con contrary, failed flight cadets exhibited a higher preflight NE/E ratio which showed a p ostflight reduction. This can occur because of overstimulation and red uced responsiveness of sympathoadrenal activity before and during flig ht, respectively. These changes may represent ct neuroendocrine respon se which might represent a failure to adapt.