title: Aerobatic flight effects on baroreflex sensitivity and sympathovagal balance in experienced pilots.
abstract: BACKGROUND
  Aerobatic flights subject pilots to accelerations and, therefore, to heavy physical workloads.
  
  
  OBJECTIVE
  Our aim was to document changes in spontaneous baroreflex sensitivity and disturbances of sympathovagal balance after exposure to "push-pull" accelerations.
  
  
  METHODS
  During 30-min flights, five aerobatic pilots performed five series of descending spirals: first, 30 s under negative (-3 Gz max), and then 30 s under positive (+4 Gz max) G loading, climbing between each series to regain altitude. A stand-test was performed before (T0), immediately postflight (PF), 1 h (PF1), and 2 h after (PF2) the flight. A Finapres apparatus recorded heart rate (HR) and BP during the stand-tests.
  
  
  RESULTS
  Resting HR was higher at PF than T0 in supine (11.2 +/- 5.3%, p < 0.01) and standing (11.0 +/- 4.9%; p < 0.05) positions. Sequence analysis of spontaneous baroflex sensitivity (BRS) and spectral analysis of HR variability showed that: a) supine spontaneous BRS did not differ between preflight and postflight, while parasympathetic modulation of HR variability tended to increase; and b) supine spontaneous BRS was higher at PF1 than PF (PF: 0.011 +/- 0.0014 ms x mmHg(-1), PF1: 0.015 +/- 0.0012 ms x mmHg(-1); p < 0.05) and parasympathetic modulation of HR variability (high frequency component) was higher at PF2 than PF (PF: 0.014 +/- 0.007, PF2: 0.039 +/- 0.009; p < 0.001).
  
  
  CONCLUSIONS
  These findings may reflect a change in the sympathovagal balance during the second hour of recovery from repeated push-pull maneuvers.
authors.affiliation: Dept. of Integrative Physiology, IMASSA, BP 73, F-91223 Bretigny-sur-Orge Cedex, France. jcjouanin@imassa.fr
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Jouanin
authors.forename: Caroline
authors.initials: C
authors.lastname: Dussault
authors.forename: Denis
authors.initials: D
authors.lastname: Tran
authors.forename: Charles-Yannick
authors.initials: CY
authors.lastname: Guézennec
mesh_terms: D000054:Acceleration; D000328:Adult; D000401:Aircraft; D000704:Analysis of Variance; D001341:Autonomic Nervous System / Q000502:physiology*; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D001795:Blood Pressure Determination / Q000379:methods; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D016014:Linear Models; D008297:Male