Background: The effects of acute mild hypoxic hypoxia (HH) and physical activity on physiological measures, signs and symptoms, mood, fatigue, cognition, and performance on a simulated flight task were investigated between 8000 (8K; 2438 m) and 14,000 ft (14K; 4267 m).
Method: In a hypobaric chamber, 16 military helicopter pilots were randomly exposed to 4 altitudes and 3 physical exertion levels. After each exercise period, participants identified targets on a designated flight path on a desktop simulator and completed a cognitive test battery. Cerebral regional and finger pulse oxyhemoglobin saturation levels (rSO2 and Spo2), heart and respiration rates were continuously monitored. Participants indicated their symptoms, mood and fatigue.
Results: rSO2 and Spo2 were affected by the increase of altitude and exercise level. Target identification accuracy and latency within the simulated flight task showed decrements at 8K, 10K (3048 m), 12K (3658 m), and 14K. Cognitive performance was degraded at 14K. More than 60% of the participants at 8K and 10K and more than 80% at 12K and 14K reported symptoms. Altitude increased symptoms, negative mood, general fatigue, and physical fatigue.
Discussion: Our findings indicate a significant influence of mild HH on a number of outcome measures at altitudes above 10K, where operational restrictions are well established. In contrast, there was no clear influence of HH on performance at lower altitudes (i.e., 8K and 10K). The occurrence of HH symptoms and the decrements in target identification latency and accuracy at 8K and 10K may negatively impact flight performance and require further study.Bouak F, Vartanian O, Hofer K, Cheung B. Acute mild hypoxic hypoxia effects on cognitive and simulated aircraft pilot performance. Aerosp Med Hum Perform. 2018; 89(6):526-535.