Comparison of heart rate variability and heart rate between individuals with different emotional stability in two situations.

OBJECTIVE: To compare heart rate variability (HRV) and heart rate (HR) between individuals with different emotional stabilities in two situations and to discuss the relationship between situation, emotional stability and HRV. METHOD: Ninety-six healthy male flying students were assessed after 60 h flying exercises by senior pilots using Criterion Assessment Scale of Emotional Stability of Flying Cadets (CASESFC) compiled by our department. They were divided into groups of high emotional stability and low stability. ECG were recorded in situations of Sternberg Dual Task and Flying and HRV components and HR were analyzed and compared. RESULT: When subjects were exposed to Sternberg dual task situation, individuals with high emotional stability had lower LFnorm (P<0.05), HFnorm (P<0.05), LF/HF ratio and HR (P<0.05) than those with low emotional stability. When it comes to flying situation, individuals with high emotional stability had higher LFnorm and HFnorm, but LF/HF ratio and HR (P<0.05) were still lower than those with low emotional stability. CONCLUSION: We found that there is a tendency which implies the situational separation of fluctuation of autonomic nervous system related to emotional stability. It suggests that the ability of an individual to adjust to outer environment depends not only on personality, temperament and cognitive module, but also on a physiological basis.

[Models of confirmatory factor analysis of the emotional stability criteria of flying students].

OBJECTIVE: To established models of confirmatory factor analysis of the emotional stability criteria of flying students, and to provide an available criteria tool for evaluating the emotional stability. METHOD: "Criterion Assessment Scale of Emotional Stability of Flying Cadets" (ACSEFC) including 9 items were compiled first by interviewing with skillful pilots or flying instructors, and then the emotional stability of 153 flying students was evaluated by these pilots or instructors. RESULT: There were high level (P<0.05) of correlation coefficients between 8 items except for item 1; three-factor design appears to be the best choice for the nine items by exploratory factor analysis; model 4 appears to have the best effect by confirmatory factor analysis. CONCLUSION: The evaluation of emotional stability of flying students can be divided into 3 parts: general manifest emotion, tense before flying and flying emotion stability.

[Effects of exercise training during 21 d -6 degrees head down bed rest on dynamic posture equilibrium and motor coordination].

OBJECTIVE: To study the effects of 21 d -6 degrees head down bed rest (HDBR) with exercise training on dynamic posture equilibrium and motor coordination. METHOD: Ten healthy young men were randomly divided into HDBR control groups and HDBR exercise groups, with 5 in each group. The subjects in the exercise group performed exercise with a bicycle ergometer in the supine position 1 h/d during bed rest. Dynamic posture equilibrium as well as isokinetic concentric muscular strength were determined before and after 21 d HD-BR. RESULT: After HDBR, average dynamic proprioception score and dynamic motor coordination decreased significantly, relative peak torque (peak torque /body weights PT/BW) also decreased significantly and accompanied with increase of the peak torque ratio between hamstrings and quadriceps (H/Q) in HDBR control groups. Average dynamic proprioception score and dynamic motor coordination in the HDBR exercise groups remained above the HDBR control groups, but the H/Q ratio showed no significant change. CONCLUSION: The results showed that exercise training during 21 d -6 degrees head-down tilt bed-rest do have beneficial effects on retaining the dynamic posture equilibrium and dynamic motor coordination of the subjects after bed rest.

[Study on relationship between emotional stability in flight and nerve system excitability].

OBJECTIVE: To study the related factors of emotional stability in flight. METHOD: Based on the operable definition of emotional stability in flight and the related literature review, 63 experienced pilots and flight coaches were investigated and the other-rating questionnaire of emotional stability in flight was established. To test the senior nerve system, Uchida Kraeplin (UK) test was administrated on 153 19-21 years old male student pilots of the second grade in the department of flight technique in China Civil Aviation College, who were selected through 13 h flight, 35 h solo flight, and acted as the standardization group. In the end, the correlation was explored between the testing results and their emotional behavioral characteristics in flight. RESULT: Significant positive correlation was found between emotional feature indexes of emotional stability in flight and excitability in UK test. CONCLUSION: The excitability in UK test are good predictors for emotional stability in flight.

[Preventive effects of exercise training on bone loss during 21 d -6 degrees head down bed-rest].

OBJECTIVE: To observe the protective effects of exercise training during 21 d -6 degrees head down bed rest (HDBR) on bone loss. METHOD: Ten healthy young men were randomly divided into HDBR group and HD-BR exercise group, with 5 in each group. Both groups were exposed to -6 degrees head down bed rest for 21 d. The subjects in the exercise group performed exercise with a bicycle ergometer in supine position 1 h/d during bed rest. Femur bone mineral density (BMD), serum bone gla protein (BGP) as well as hydroxyproline/creatinine (HOP/Cr) were determined before and during 20 d HDBR. RESULT: As compared with the before HDBR values, average femur BMD decreased by 5.8% and 0.9% for HDBR group and HDBR and exercise group respectively. HOP/Cr significantly increased in the HDBR group and was significantly higher than the HDBR exercise group. BGP decreased in both groups with no significant difference. CONCLUSION: Exercise during 21 d -6 degrees HDBR is beneficial in preventing bone loss.

[Application of lower body negative pressure (LBNP) in aerospace medicine].

Effects of LBNP is similar to that produced by gravitational force, especially as a stress factor on the cardiovascular system as has been concerned in the area of aerospace medicine. This paper described experimental equipment, methods and physiological effects of LBNP, especially its application in the area of aerospace medicine. Several aspects for future research were put forward.

[Effects of +Gx load on energy metabolism of brain tissue in rats].

Objective. To observe the changes of energy metabolism of brain tissue in rats under +Gx loads, and to explore its possible role in changes of brain function and work efficiency induced by +Gx stress. Method. Forty-five male Wistar rats were randomly divided into control, +5 Gx, +10 Gx, +15 Gx and +20 Gx group. Each group was exposed to the corresponding G value for 3 min. After that, cortical adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and lactic acid (LA) content, lactate dehydrogenase (LDH) activity were measured. Result. Compared with the control group, the cortical (LA) content increased significantly after +5 Gx, +10 Gx, +15 Gx and +20 Gx exposure (P<0.01). Cortical ADP content and ratio of ADP/AMP and AMP/ATP increased significantly after +10 Gx, +15 Gx and +20 Gx exposure (P<0.01), whereas ATP content, energy charge and LDH activity decreased significantly (P<0.05 or 0.01). Cortical AMP content increased significantly after +15 Gx and +20 Gx exposure (P<0.05 and 0.01). Conclusion. It is suggested that +Gx load can result in obvious depression of brain energy metabolism, which could be an important reason for the change of brain function and work efficiency induced by +Gx stress.