Cognitive performance, fatigue, emotional and physiological strains in simulated long-duration flight missions

Pilots in long-duration flight missions in single-seat aircraft may be affected by fatigue. This study determined associations between cognitive performance, emotions and physiological activation and deactivation - measured by heart rate variability (HRV) - in a simulated 11-h flight mission in the 39 Gripen aircraft. Twelve participants volunteered for the study. Perceived fatigue was measured by the Samn-Perelli Fatigue Index (SPFI). Cognitive performance was measured by non-executive and executive tasks. Emotions were assessed by the Circumplex Affect Space instrument. HRV was considered in relation to the cognitive tasks in four time points - Hours 3, 5, 7, 9 - and their associations with emotional ratings. Results indicated a decrease in performance in the non-executive task after approximately 7 h. This result was correlated with self-reported measures of fatigue. HRV, assessed by indices of parasympathetic modulation, remained unchanged for both non-executive and executive tasks over time (p > .05 for all). Significant correlations were observed between emotions and HRV; with increased boredom, increased passiveness, decreased stimulation, and decreased activeness, HRV indicators increased (p < .05). This suggests that a low self-regulatory effort for maintaining performance in these conditions was prevalent and that pilots could adapt to some degree to the demands and fatigue of long-duration missions.