Analysis of heart rate variability during emergency flight simulator missions in fighter pilots.

Introduction: Managing emergency situations in different simulated flight segments can entail a workload that could affect the performance of military pilots. The aim was to analyse the modifications in neurovegetative balance (using HR variability, HRV) of professional fighter pilots attending learning/training sessions on emergency situations in a flight simulator.

Methods: A total of 18 pilots from the Spanish Air and Space Force were included. HRV was recorded simultaneously during diverse simulated emergency situations in three different flight segments: take-off, in-flight and landing.

Results: The comparison between take-off and in-flight revealed a statistically significant increase (p<0.05) in percentage of consecutive RR intervals that differ by more than 50 ms from each other (pNN50), root mean square of the successive differences (rMSSD), standard desviation 1 and 2 (SD1 and SD2), and a statistically significant decrease (p<0.000) in stress score (SS) and in the sympathetic to parasympathetic ratio (S:PS). Between flight and landing, a statistically significant increase (p<0.05) in mean HR, minimum HR, maximum HR, SS and S:PS was shown, while experiencing a significant decrease (p<0.000) in pNN50, rMSSD and SD2. Finally, between take-off and landing, the variables which showed significant changes (p<0.05), with these changes being a significant increase, were mean HR, minimum HR, maximum HR, rMSSD, SD1 and SD2. SS and S:PS ratios showed a statistically significant decrease (p<0.000).

Conclusions: An emergency situation in a flight simulator manoeuvre produced an anticipatory anxiety response in pilots, demonstrated by low HRV, which increased during the flight segment and decreased during the landing segment of the flight. Trial registration number NCT04487899.