Effects of hypobaric-hypoxia on the salivary cortisol levels of aircraft pilots.
BACKGROUND
There has been limited characterization of the endocrine stress reactivity of aircraft pilots under the adverse environmental condition of hypobaric-hypoxia. This seems especially true with respect to using the non-invasive technique of salivary hormonal analysis. Thus, the purpose of this study was to characterize the salivary cortisol response to such an environmental stress.


METHODS
Some 53 pilots were exposed to 30 min of hypobaric-hypoxia (final pressure, 540 hPa). The salivary cortisol levels were measured at baseline (0 min), at 15 and 30 min into exposure (+15 and +30 min) and 30 min after the exposure ended (+60 min). The cortisol response of each pilot was classified according to the difference between the +30 min and 0 min values. Responder categories were: increase (I), decrease (D) or no change (N).


RESULTS
Subjects were not evenly distributed among the three response categories (p < 0.05). The distributions were as follows; D = 5 pilots (9.4%), N = 17 pilots (32.1%), and I = 31 pilots (58.5%). Further, significant (p < 0.05) changes in cortisol levels were noted over the sampling times for the D (+15 min to +60 min < 0 min) and 1 (+15 min to +60 min > 0 min) responders, as well as between the D, N, and I responders at the +15 to +60 min sampling times.


CONCLUSIONS
We conclude that no single consistent change in salivary cortisol level occurred among the different subjects in response to the level and duration of hypobaric-hypoxia studied.
Obmiñski
Z
Z
Department of Endocrinology, Institute of Sport, Warsaw, Poland.
Golec
L
L
Stupnicki
R
R
Hackney
A C
AC
D000328:Adult; D000337:Aerospace Medicine; D003665:Decompression Sickness / Q000145:classification / Q000503:physiopathology*; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis*; D000860:Hypoxia / Q000145:classification / Q000503:physiopathology*; D008297:Male; D012463:Saliva / Q000737:chemistry*; D013312:Stress, Physiological / Q000145:classification / Q000503:physiopathology*; D013997:Time Factors
D006854:Hydrocortisone