title: Preliminary Results of the LF/HF Ratio as an Indicator for Estimating Difficulty Level of Flight Tasks.
abstract: BACKGROUND
  The main aim of this study was to differentiate the magnitude of a pilot's heart rate variability (HRV) when performing assisted and unassisted flights, as well as simple and complex flight tasks.
  
  
  METHODS
  Cardiac monitoring in flights was carried out using a compact, mobile ECG recorder. A frequency analysis of the heart rate (HR) signal was performed to determine the ratio of low-frequency spectral power (LF) to high-frequency spectral power (HF).
  
  
  RESULTS
  The LF/HF ratio observed in the zone (M=1.047, SD=0.059) was significantly different than the LF/HF calculated preflight (M=0.877, SD=0.043) and postflight (M=0.793, SD=0.037). There was no main effect of the flight type (unassisted zone flight vs. zone flight with an instructor) on the LF/HF parameter. However, greater psychophysiological load of a pilot was observed in the training zone flights when compared to simple circle flights (main effect of the flight type).
  
  
  CONCLUSIONS
  As the LF/HF ratio turned out to be significantly higher in the zone than pre- and postflight, this parameter can be useful for predicting the risk of excessive stress and arousal of pilots during flights. Based on the LF/HF ratio we can also estimate difficulty level of flight tasks, because our research has shown higher values of this parameter in the training zone flights than in simple circle flights.
authors.affiliation: Technical Department of Aeromedical Research and Flight Simulators, Military Institute of Aviation Medicine, Warsaw, Poland.
authors.forename: Franciszek W
authors.initials: FW
authors.lastname: Skibniewski
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Dziuda
authors.forename: Paulina M
authors.initials: PM
authors.lastname: Baran
authors.forename: Mariusz K
authors.initials: MK
authors.lastname: Krej
authors.forename: Sylwester
authors.initials: S
authors.lastname: Guzowski
authors.forename: Marcin A
authors.initials: MA
authors.lastname: Piotrowski
authors.forename: Olaf E
authors.initials: OE
authors.lastname: Truszczyński
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D000401:Aircraft; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D015233:Models, Statistical; D012815:Signal Processing, Computer-Assisted; D013312:Stress, Physiological / Q000502:physiology*; D013315:Stress, Psychological / Q000503:physiopathology*; D013647:Task Performance and Analysis; D055815:Young Adult