Objective To investigate the effects of plateau flight on physiological parameters and flight workload of high performance fighter pilots.Methods Thirteen healthy male highperformance fighter pilots entered plateau in 2 batches,8 pilots stationed for 3 months and the others stationed for 1 week.Pilots' heart rate was tested before flight and compared with the referenced value that previously tested at normal altitude level.Pilots＇ physiological parameters were detected for 25 sorties that covered 4 flight conditions (patrol,air combat,night flight,virgin flight on plateau).The changes of heart rate and respiratory rate were analyzed.Results ① Pilots' heart rate detected before flight was significant higher than the referenced value (t=5.447,3.269,P＜0.05).②Heart rate significantly varied in different flight phases and among different flight conditions (F=9.831-204.906,P＜0.01).Pilots' heart rate in preparation,taxiing and taking-off,approaching and landing phases was significant higher than that in level flying phase (P＜0.01).Condition 4 (virgin flight on plateau) caused higher heart rate than that in other flight conditions in all phases except in quiet (P＜0.01).③There was significant difference on respiratory rate in different flight phases and conditions (F=1.971-140.035,P＜0.01).Pilots＇ respiratory rate in the landing of condition 2,3 and 4 was much higher than that in condition 1.Pilots' respiratory rate in all phases of flight condition 4 was the highest (P＜0.05 or 0.01).④Pilots' heart rate significantly reduced when backup oxygen supplied in landing and the mean decrease was (15.89±6.37) beat/min (t=5.580,P＜0.01).Conclusions For the pilots stationed on plateau the physiological and flight workloads are much higher than theirs on plain.It is recommended that keeping pilots mask wearing and backup oxygen supply in landing would be beneficial to reduce the cardio-pulmonary loads caused by hypoxia.

Objective To investigate the effects of 8-h simulated flight on physiological indices of flying cadets and evaluate the effectiveness of mental fatigue countermeasures for long haul flight.Methods Twenty healthy male military flying cadets were randomly divided into control group and test group.Eight-hour flight was performed on JL-8 flight simulator.Mental fatigue countermeasure was only used in test group.ECG was recorded and heart rate (HR),heart rate variability (HRV)and body motion intensity were analyzed.Results During 8-h simulated flight,mean HR of test group was lower than that of control group (F =184.241,P=0.000).As compared with flight stage,HR of test group was lower than that at rest stage (F=17.564,P=0.000),while there was no significant difference of HR in control group between rest and flight stage (F=2.014,P=0.156).As compared with flight stage,low frequency normalized unit (LFnu) component and the ratio of LF and HF of control group in flight stage increased significantly,while high frequency normalized unit (HFnu) component decreased significantly at rest stage.The change of body motion intensity was similar to LFnu.Conclusions The mental fatigue countermeasure presented in this study is effective for countering mental fatigue.Further investigation is suggested and integration with other flight fatigue countermeasures will hopefully to help pilot releasing long haul flight fatigue and ensure air safety.

Objective To evaluate the effectiveness of mental fatigue countermeasure in simulated long haul flight. Methods Sixteen male military student pilots were randomly and averagely divided into control group and test group.The 8-hour simulated long haul line flight was performed on K-8 flight simulator.Mental fatigue countermeasure was used in test group.Mental fatigue of the two groups was evaluated and compared by student pilot's decoding score,flying score and Self-Rating Anxiety Scale (SAS) scores. Results As the flying hours increased,the decoding scores and the flying scores of control group decreased significantly (F =4.406, 10.166;P=0.039,0.002),but the change of these scores was not significant in test group (F =1.015,0.780; P=0.405,0.477).The two scores of the control group decreased significantly after the continuous flight for 4 hours (P＜0.05),while those of the test group showed no difference in whole flight (P ＞ 0.05).The change of SAS scores of control group was not significant (t =1.032,P=0.329),while the SAS score of test group decreased significantly (t =3.222,P =0.010).Conclusions The mental fatigue countermeasure presents apparent effectiveness for countering the mental fatigue in long haul flight.