INTRODUCTION: 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.
INTRODUCTION: 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.
Authors: Katherine Stamatakis; Mark H Sanders; Brian Caffo; Helaine E Resnick; Dan J Gottlieb; Reena Mehra; Naresh M Punjabi Journal: Sleep Date: 2008-07 Impact factor: 5.849