A study of USAF air traffic controller shiftwork: sleep, fatigue, activity, and mood analyses.

BACKGROUND: The purpose of this study was to evaluate the shift-specific sleep, general activity levels, mood and cognitive performance of air traffic controllers (ATCs) working a forward 2-2-2 rapid rotation shift schedule. HYPOTHESIS: ATCs are more fatigued on the night-shift. METHODS: ATCs recorded their sleep, oral temperature and subjective fatigue levels, took a computerized cognitive performance battery (n = 13) and completed the Profile of Mood States questionnaire (POMS) (n = 12). Actigraphs were used to objectively monitor general activity levels and score sleep and the restfullness of scored sleep (n = 9). Analyses were made on the basis of duty shift, post-shift, day of shift, and duty location. RESULTS: There was significantly more actigraph scored sleep (85 min, p = 0.038), subjectively reported sleep (26 min, p = 0.009) and subjectively measured fatigue (p < 0.001) and confusion (p = 0.003) for the ATCs while they were on-duty on the night-shift. The night-shift was also associated with decreased vigor (p = 0.039) and general activity levels (p = 0.017). Significantly more sleep was reported (7.6 h, p = 0.01) and scored by actigraph (4.7 h, p = 0.02) following the swing-shift than following the day-shift. The radar approach ATCs reported greater confusion (p = 0.019) and less vigor (p = 0.002) than the tower ATCs. Insufficient trials were available for direct performance analysis. CONCLUSIONS: ATCs on the night-shift of a forward rapid rotation shift schedule appear to be falling asleep and report increased confusion and fatigue. Further study is indicated.

Crew fatigue during simulated, long duration B-1B bomber missions.

Crew fatigue associated with successive and unaugmented 36 h missions was evaluated in B-1B simulators. Data were obtained from 32 operationally qualified crewmembers. All crew-members completed three consecutive, long duration missions, each preceded by 33 to 35 h of crew rest. Oral temperature, salivary melatonin and cortisol, as well as actigraph and subjective measures, were collected during all missions. Temperature and melatonin data indicate that crews maintained their local home base circadian cycles. Elevated cortisol and subjective fatigue during the first mission indicate that it was the most difficult of the three. Furthermore, quality and duration of sleep were lowest during the first mission. These findings emphasize the need for realistic training in long duration fatigue management to improve the safety and effectiveness of the first and subsequent missions.