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Background: Acceleration load causes several physiological changes that play important roles in pilot performance. One of the problems is determining individual factors responsible for the differences in changes in the level of central nervous system (CNS) arousal after exposure to acceleration loads. We were interested in whether the coping style and anxiety as a trait might differentiate the subjects in terms of reactions of the CNS to +Gz load-related stress., Methods: Examined were 31 male volunteers with ages between 23 and 30 yr. Measurements were obtained under controlled conditions before, during, and every 2 min up to 12 min after centrifugation. The study was conducted using the Coping Inventory for Stressful Situations (CISS) and State Trait Anxiety Inventory. The value of Critical Flicker Fusion Threshold (CFFT) corresponded to the level of CNS arousal., Results: Two significantly different trends of changes in CNS arousal were identified: class 1 (higher level of fatigue following +Gz load) and class 2 (lower level of fatigue following +Gz load). Significant differences were observed in CISS scores with Task-Oriented Coping value in class 1 (M = 65.94, SD = 5.47) being considerably greater than in class 2 (M = 62, SD = 4.37). For Emotion-Oriented and Distraction Coping, the mean value in class 1 (M = 29.53, SD = 7.72; M = 16.82, SD = 3.8) was significantly lower than in class 2 (M = 34.33, SD = 6.68; M = 19.42, SD = 3.4)., Discussion: The nature of the changes in CFFT values over time is associated with coping style. Coping styles are very valuable in the prediction of CNS arousal caused by exposure to +Gz stress.Biernacki MP, Lewkowicz R, Zieliński P, Wojtkowiak M. Coping and changes in arousal after exposure to +Gz load. Aerosp Med Hum Perform. 2017; 88(11):1034-1039.

Introduction: An important problem for pilots is visual disturbances occurring under +Gz acceleration. Assessment of the degree of intensification of these disturbances is generally accepted as the acceleration tolerance level (ATL) criterion determined in human centrifuges. The aim of this research was to evaluate the visual-motor responses of pilots during rapidly increasing acceleration contained in cyclic intervals of +6 Gz to the maximum ATL., Methods: The study involved 40 male pilots ages 32-41 yr. The task was a quick and faultless response to the light stimuli presented on a light bar during exposure to acceleration until reaching the ATL. Simple response time (SRT) measurements were performed using a visual-motor analysis system throughout the exposures which allowed assessment of a pilot's ATL., Results: There were 29 pilots who tolerated the initial phase of interval acceleration and achieved +6 Gz, completing the test at ATL. Relative to the control measurements, the obtained results indicate a significant effect of the applied acceleration on response time. SRT during +6 Gz exposure was not significantly longer compared with the reaction time between each of the intervals. SRT and erroneous reactions indicated no statistically significant differences between the "lower" and "higher" ATL groups., Conclusion: SRT measurements over the +6-Gz exposure intervals did not vary between "lower" and "higher" ATL groups and, therefore, are not useful in predicting pilot performance. The gradual exposure to the maximum value of +6 Gz with exposure to the first three intervals on the +6-Gz plateau effectively differentiated pilots.

Objectives: Back pain in Air Force fast jet pilots has been studied by several air forces and found to be relatively common. The objective of the study was to determine the prevalence and degree of the pain intensity in the cervical, thoracic and lumbar spine, subjective risk factors and their effect on the pilots' performance while flying high maneuver aircrafts and the consequences for cognitive deficiencies., Material and Methods: The study was designed as a retrospective, anonymous questionnaire survey, collecting data on the age, aircraft type, flying hours, pain characteristics, physical activity, etc. The study was participated by 94 pilots aged 28-45 years (mean age: 35.9 ± 3.3 years), actively flying fast jet aircrafts Su-22, Mig-29 and F-16. The estimates regarding the level of the subjective back pain were established using visual analogue scales (VAS)., Results: The values of the Cochran and Cox T-test for heterogeneous variances are as follows: for the total number of flying hours: F = 2.53, p = 0.0145, for the pilot's age: F = 3.15, p = 0.003, and for the BMI factor F = 2.73, p = 0.008., Conclusions: Our questionnaire survey showed a significant problem regarding spinal conditions in high performance aircraft pilots. The determination of the risk factors may lead to solving this problem and help eliminate the effect of the unfavorable environment on piloting jet aircrafts. Experiencing back pain during the flight might influence the mission performance and flight safety. The costs of pilots education are enormous and inability to fly, or even disability, leads to considerable economic loss. More research on specific prevention strategies is warranted in order to improve the in-flight working environment of fighter pilots.

Introduction: Pilots flying at very high speed are exposed to the effects of prolonged accelerations while changing their flight path. The aim of this research was to assess the impact of sustained accelerations on the visual-motor response times of pilots and the acceleration tolerance level (ATL) as a measure of pilots' endurance to applied +G(z)., Method: The study involved 18 young pilots, 23-25 yr of age. The subjects' task was to quickly and accurately respond to the light stimuli presented on a light bar during exposure to acceleration at +4.5 G(z) and until reaching the ATL. Simple response time (SRT) measurements were performed using a visual-motor analysis system throughout the exposures, which allowed the assessment of a pilot's ATL., Results: The pilots' ATL ranged from 270 to 366 s (Mean = 317.7 +/- 26.15 SD). The analysis of the SRT indicated a significant effect of duration of acceleration on the visual response time. The results of the post hoc comparisons showed that SRT increased with longer durations of the same level of +G(z) load and then decreased, reaching values similar to the controls., Conclusion: Exposure to prolonged acceleration of +4.5 G(z) significantly increases SRT. There was no statistically significant difference in SRT between the pilots with "short" and "long" time exposures. A pilot's SRT during a prolonged +4.5 G(z) exposure could be a reliable indicator of pilot G performance in the fast jet. Deterioration of SRT may be used to predict imminent +G(z) endurance limits between pilots with widely varying endurance abilities.

Objectives: Human reactions to environmental changes have been the subject of numerous investigations related to pathophysiology, aviation psychology, aviation, and sports. The present study aimed at evaluating the perception of light stimulus via the Critical Flicker Fusion threshold (CFF) measurements among aviation pilots., Materials and Methods: The study was carried out under hypoxic conditions corresponding to 5000 m altitude, for a period of 30 min, without the use of supplemental oxygen. Fourteen volunteer pilots, 23-30 years of age, were examined in the hypobaric chamber (HC). The measurements were performed at normobaria and at the initial and final phase of hypoxia. Heart rate (HR) and blood oxygen saturation (SaO2) were monitored., Results: The high altitude hypoxia was found to produce a decrease in the CFF threshold F(3.39) = 3.207, p < 0.05, and SaO2 F(3.39) = 52.651, p < 0.001, as well as HR increase F(3.39) = 7.356, p < 0.001. The results indicate that the higher the decrease in SaO2 under hypoxic conditions, the higher the decrease in CFF r = .567 p < 0.05. Likewise, the higher the increase in HR, the higher the decrease in CFF r = -0.491 p < 0.05., Conclusions: Under hypoxic conditions, the perceptual ability of the pilots is gradually decreasing. This has been confirmed by the findings of the physiological examinations. The authors express an opinion that it would be advisable to introduce CFF measurement into the hypobaric chamber tests as it allows individual assessment of the pilot's perceptual ability under conditions of incomplete physiological compensation of the high altitude hypoxia.

Objectives: Visual disturbances are commonly accepted criteria for acceleration tolerance assessment. Researchers during centrifuge experiments use them as a safe criterion for cessation of acceleration exposure. Visual disturbances analysis is a non-invasive method of assessing retinal blood flow. Limitation of visual stimuli perception is a measure of physiological state of the experiment participants before hemodynamic changes, which reach a critical level manifested by G-induced loss of consciousness. Detection of these disturbances play an important role during the acceleration tolerance assessment. In this study, an attempt was made to answer the question on how many mistakes or incorrect reactions had to be identified to classify the ability of the pilot to fly on military jets., Materials and Methods: A new computer-aided research apparatus of our own design was used to assess visual disturbances, being a criterion of +Gz tolerance. In the center of monitor screen, a line of 3 light points was projected. During the centrifuge test, green lateral lights randomly changed their shapes from circles to squares while central light, being a point of vision fixation, remained unchanged. To assess its efficacy, 14 volunteers participated in the tests with various stimuli exposure. The authors aimed at selecting parameters of stimuli and exposure so that the division of reactions presented in the table would correspond with the score scale appropriate for our goals., Results: Preliminary tests showed that appropriately selected light intensity of the exposed stimuli enables the use of test results to assess the number of erroneous reactions, and consequently the level of pilots' concentration during centrifuge tests., Conclusions: It has been found that the chosen luminance range of the projected light points is correct as it allows to evaluate the reactions, which should be considered erroneous. Additionally, prolongation of the correct reaction time to the mean value of about 400 ms facilitates better differentiation of results. Proper results evaluation, depending on the number of errors, lack of reactions or prolonged reactions made the assessment easier with computer-aided methods.

The goal of this paper was studying the effectiveness of frequently repeated low values of long duration acceleration on circulatory system response during gradual onset rate of acceleration on a human centrifuge.

The effects of acceleration (Gz) on changes in the levels of cortisol in saliva and of cortisol and testosterone in serum have been studied in 48 cadet pilots exposed to a linear acceleration gradient (0.2 G/s) until a loss of coordination when the mean G value was found to be 5.94 +/- 0.57. Three patterns of salivary cortisol responses were discerned based on Gz-induced significant changes: increase (I; n = 20), decrease (D; n = 8), the magnitude of changes being dependent on the pre-Gz values. Fifteen min after the Gz load, the mean salivary cortisol was significantly higher from the pre-Gz value in all subjects combined. In 19 subjects, who consented to blood sampling, significant increases in serum cortisol were observed both 3 and 15 min post-Gz (by 37 and 57% respectively) while, a significant increase in serum testosterone concentration has been observed only 3 min post-Gz. Testosterone levels 3 min post-Gz were significantly correlated with the final Gz values (r = 0.54; p < 0.05). A significant correlation was also observed between all salivary and serum cortisol values combined (r = 0.696; p < 0.001). It has been concluded that acceleration stress, although of very short duration, proved very potent in eliciting glucocorticoid and androgen responses.

Twenty-five men with decreased acceleration tolerance limits were subjected to two weeks centrifuge training, in which selected characteristics of +Gz acceleration (head-feet directed) were applied. The training loads were controlled basing on the responses of blood flow velocity and heart rate. The results show that the human centrifuge training in which the graded loads are based on measurement of these parameters, increases acceleration tolerance limits. It is also demonstrated that the human centrifuge training methods can be used in pilots after convalescence period or on finding lowered acceleration tolerance produced by other causes. The physical and physiological methods of increasing acceleration tolerance limits (ATL) consist some of the most important and urgent problems of today to be solved in modern military aviation. This demand is produced not only by the systematically increasing requirements as to the highest health performance of the military pilot, but also by the enormous costs of the flying equipment and training. In the group of different methods of increasing ATL, the human centrifuge training is an open problem. The available literature presents only a few reports in which the +Gz acceleration (i.e. head-pelvis directed) was used as the loading stimulus in pilots' training. The reasons for the lack of interest in this direction of examination include: easily developed decompensation of the circulatory system; cummulated effects of acceleration, and lack of optimal criteria to evaluate the body systems loads. Moreover, the positive effects of training could be baffled by the above mentioned factors.(ABSTRACT TRUNCATED AT 250 WORDS)