Aerobatic flight effects on baroreflex sensitivity and sympathovagal balance in experienced pilots.
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.
Jouanin
Jean-Claude
JC
Dept. of Integrative Physiology, IMASSA, BP 73, F-91223 Bretigny-sur-Orge Cedex, France. jcjouanin@imassa.fr
Dussault
Caroline
C
Tran
Denis
D
Guézennec
Charles-Yannick
CY
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