Objective:To find out about the sentiment about the current physical training among Air Force pilots (cadets), propose methods for optimizing their programs of physical training, and to enhance the effectiveness of training in order to improve flight adaptability.Methods:A total of 1 135 pilots (cadets) were randomly selected as the subjects and divided into 3 groups according to types of aircraft and types of personnel: group A (pilots of fighters, bombers and advanced trainers), group B (pilots of fighter bombers, transporters, helicopters, special aircraft and junior trainers), and group C (flying cadets). A questionnaire survey was conducted to collect data on current physical training among pilots and flying cadets.Results:A total of 1 135 questionnaires were distributed, with 1 086 valid responses collected, yielding an effective response rate of 95.68%. Of the 1 086 participating pilots (cadets), 209 were in Group A, 499 in Group B, and 378 in Group C.There was statistically significant difference in the frequency and duration of weekly physical training between the 3 groups ( χ2=82.23, 61.56, both P<0.001). The proportion of participants engaging in >3 h weekly physical training sessions was significantly higher in group C (71.7%) than in group A (38.8%) and group B (44.9%). Significant differences were observed in weekly training durations between group C and group A (all P<0.05), as well as between group C and group B in the training durations of <3 h and 5-7 h (all P<0.05). The percentage of subjects who trained for 5-7 h per week was the highest in group C (41.5%). In groups A and B, pilots mostly trained for 3-<5 h per week (51.7% and 39.9%, respectively). The survey on the willingness to adjust training programs revealed statistically significant differences between the 3 groups in their willingness to engage in muscle strength training, coordination training, specific ability training, and adjustment of intensities of core training ( H=46.23, 16.12, 22.03, 60.68, all P<0.001). No significant difference was observed in their willingness to have aerobic training programs adjusted ( P>0.05). Group C was significantly different from groups A and B in their preference for adjustment in training programs related to muscle strength, coordination, specific abilities, and in core training programs (all P<0.01). Group C was mostly in favor of "increasing" muscle strength, coordination, and core training while opting for "no change" in aerobic training and specific ability training. Groups A and B preferred "no change". Regarding their willingness to have training intensities revised, statistically significant differences were observed between the 3 groups ( H=15.58, 19.08, 8.17, 58.01, P<0.001, <0.001, =0.017, <0.001), but no significant difference was found in their preference for adjustment of aerobic training intensities ( P>0.05). Group C showed much more preference for intensity adjustment related to muscle strength, coordination, specific abilities, and core training programs than groups A and B (all P<0.05 or 0.01). All the 3 groups predominantly favored "no change" in training intensities. Conclusions:Pilots of different aircraft types generally meet the requirements of the current physical training programs. However, the frequency of physical training for pilots (cadets) requires more rigorous supervision. Flying cadets can adaptively engage in targeted training programs. Pilots of fighters, fighter bombers and advanced trainers should care about the intensity of aerobic training while giving more weight to load resistance physical training. Pilots of other types of aircraft should devote more effort to core training programs.

Objective:To investigate the incidence of hearing loss among helicopter flying personnel, and to analyze the contributing factors.Methods:Basic data of 443 male helicopter flying personnel who received physical examinations at Beidaihe Rehabilitation and Recuperation Center of PLA between March and June 2024 was collected. The hearing threshold levels were measured at 8 frequencies: 250, 500, 1 000, 2 000, 3 000, 4 000, 6 000 and 8 000 Hz. Routine blood tests and blood biochemical tests were performed. Based on the results of pure-tone audiometry, the participants were divided into 2 groups: the hearing loss group (hearing threshold ≤20 dB HL) and the normal hearing group (hearing threshold >20 dB HL). The basic data, routine blood results, and blood biochemical indicators were compared between the 2 groups before the contributors to hearing loss were analyzed.Results:A total of 443 helicopter flying personnel were included in the study, with 82 cases (18.51%) in the hearing loss group and 361 cases (81.49%) in the normal hearing group. There were significant differences in age and pulse between the flying personnel in the 2 groups ( t=2.13, 2.78, P=0.034, 0.006). Among the blood routine indicators, only the mean platelet volume (MPV) was significantly different ( t=2.26, P=0.025). Among the blood biochemical indicators, only homocysteine (HCY) revealed statistically significant difference ( Z=2.30, P=0.021). The determinants of hearing loss in helicopter flying personnel were age ( OR=1.046, 95% CI: 1.060-1.361), pulse ( OR=1.201, 95% CI: 1.060-1.361), MPV ( OR=1.365, 95% CI: 1.016-1.834) and HCY ( OR=1.065, 95% CI: 1.033-1.097). Conclusions:Age, pulse, the MPV and HCY levels can all contribute to hearing loss, and the MPV and HCY can serve as potential biomarkers for hearing loss in helicopter flying personnel. Potential hearing loss should be detected early and personalized interventions should be implemented. Noise exposure should be monitored more rigorously to reduce the risk of occupational hearing loss for helicopter flying personnel and ensure flight safety.

Objective:To explore the applicability of modified comprehensive interventions in the treatment of non-severe dry eye syndrome in military pilots.Methods:A total of 88 military pilots with non-severe dry eye syndrome admitted to the Special Service Department of the 988th Hospital of the Joint Logistic Support Force between December 2021 and December 2023 were divided into an intervention group and a control group using the random number table method, with 44 cases in each. The intervention group received modified comprehensive interventions, while the control group underwent conventional treatment. The Ocular Surface Disease Index (OSDI), break-up time, tear meniscus height, changes in meibomian gland function, and levels of satisfaction of military pilots were compared between the 2 groups. The correlations between the OSDI, break-up time, tear meniscus height and levels of satisfaction were analyzed.Results:Before treatment, there was no significant difference in the OSDI between the 2 groups ( P>0.05). After 4 weeks of treatment, the changes in the OSDI of military pilots were smaller in the intervention group than in the control group ( t=3.21, P=0.002). After 2 and 4 weeks of treatment, the break-up time (both P<0.001) and tear meniscus height ( P<0.001, =0.012) of pilots in the intervention group exceeded those of the control group. In both groups, the break-up time (all P<0.001) and tear meniscus height (all P<0.001) kept increasing after treatment. After 4 weeks of treatment, there were significant differences in the distribution of meibomian gland function between the 2 groups ( Z=-2.55, -2.41, -2.29, P=0.011, 0.016, 0.022). Clinical care, procedure flow, and health education scored higher in the intervention group than in the control group during the survey on levels of satisfaction with the treatment ( t=6.55, 6.77, 3.63, all P≤0.001). The OSDI was negatively correlated with clinical care, procedure flow and health education ( r=-0.286, -0.275, -0.363, P=0.007, 0.010, 0.001) while the break-up time was positively correlated with clinical care and procedure flow ( r=0.248, 0.278, P=0.020, 0.009). Conclusions:The implementation of modified comprehensive intervention measures for dry eye syndrome in military pilots can effectively improve clinical symptoms and leave military pilots more satisfied.

Objective:To investigate the selection of treatment methods for renal tumors in pilots as well as the clinical significance of robot-assisted surgery by summarizing the process of robot-assisted surgery in the treatment of renal cell carcinoma in a pilot.Methods:The diagnosis, robot-assisted surgery and aeromedical assessment of a pilot with renal cell carcinoma were reported, and the related literature was reviewed.Results:The patient was a 44-year-old male transporter pilot, who was diagnosed with a left renal mass in the middle-lower pole of the kidney during a routine abdominal CT scan. After detailed preoperative evaluation that ruled out the possibility of distant metastasis and other surgical contraindications, the patient underwent robot-assisted laparoscopic partial nephrectomy in August 2022. The postoperative recovery went well, and renal function remained within normal limits at follow-ups. In March 2023, the pilot was concluded as qualified for flight after aeromedical assessment.Conclusions:Robot-assisted partial nephrectomy can significantly reduce surgical trauma, lower the risk of complications, and maximally preserve renal function. It is a good approach to renal tumors in pilots who can recover quickly.

Objective:To investigate the feasibility of flight fatigue being detected via photoplethysmography (PPG) and regional cerebral oxygen saturation (rScO 2) in order to address the challenges posed by flight fatigue during prolonged or multiple consecutive flights. Methods:A total of 16 healthy male volunteers were enrolled. A wireless cerebral oximetry monitor headband was employed to collect PPG and rScO 2 data from the forehead while a multi-lead physiological data acquisition system was used concurrently to record three-lead electrocardiograms (ECGs). After 18 h of sleep deprivation, each volunteer performed a flight-simulating task, which was divided into 4 stages: the baseline period (T1), relaxation period (T2), early fatigue period (T3) and severe fatigue period (T4). Five-minute data was collected from each stage for analysis using AcqKnowledge 6.0. Heart rate (HR) and 3 HR variability (HRV) metrics, namely standard deviation of NN intervals (SDNN), root mean square of successive differences (RMSSD), and low frequency to high frequency power ratio (LF/HF), were computed independently from both ECG and PPG traces. The mean rScO 2 value for each stage was used to represent the cerebral oxygen saturation during that stage. The intra-class correlation coefficient (ICC) was employed to assess the consistency of the measurements, and the differences in HR and HRV indicators of the volunteers in the 4 stages of the experiment were analyzed. Results:The HR measured by ECG and PPG was highly consistent across the 4 stages among the 14 volunteers ( ICC=0.951, 0.963, 0.962, 0.963, P=0.013, 0.011, 0.021, 0.015), so were SDNN, RMSSD and LF/HF values ( ICC=0.935-0.983, all P<0.05). HR values calculated with either method showed significant differences across the 4 stages in the 14 volunteers ( F=21.63, 20.52, P=0.007, 0.008). HR gradually declined from T1 to T4, and was significantly lower at T4 than at T1 ( P=0.011, 0.009). There were significant differences in SDNN ( F=22.31, 24.26, P=0.006, 0.003), RMSSD ( F=22.30, 22.26, P=0.006, 0.006), and LF/HF ( F=20.37, 25.13, P=0.009, 0.002) across the 4 stages among the 14 volunteers. SDNN and RMSSD kept increasing as fatigue was intensified, while LF/HF decreased correspondingly. Statistically significant differences were found in SDNN, RMSSD and LF/HF values between T4 and T1 (all P<0.01). rScO 2 measured during the flight-simulating trial also differed significantly across the 4 stages ( F=21.39, P=0.007). rScO? at both T3 and T4 was significantly lower than at T1 ( P=0.009, 0.007). Conclusions:PPG can replace ECG for monitoring HR and HRV indicators under flight fatigue. Furthermore, the combination of PPG with rScO 2 monitoring allows for earlier detection of flight fatigue. This study is expected to offer a user-friendly and non-invasive approach to management of pilot fatigue.

Objective:To investigate the prevalence of flight fatigue among helicopter flying personnel and analyze its contributors in order to provide data for related interventions.Methods:A cross-sectional study was conducted among 404 helicopter flying personnel between October 8, 2021 and July 31, 2022. Data was collected using a self-designed questionnaire, involving the demography of these subjects, sleep-related factors, flight fatigue, perceived causes of fatigue and coping strategies. The Pittsburgh Sleep Quality Index (PSQI), National Aeronautics and Space Administration Task Load Index (NASA-TLX) and Modified Fatigue Impact Scale (MFI-20) were used to assess sleep quality, mental workload, and levels of flight fatigue over the past month. The total scores of MFI-20 were compared across demographic groups, and correlations with PSQI and NASA-TLX scores were analyzed. Multiple linear regression was performed to identify the determinants of flight fatigue.Results:①Demography: among the 404 helicopter flying personnel, 92.8% (375/404) were pilots and 7.2% (29/404) navigators. As for years of service, 41.6% (168/404) served less than 5 years, while 58.4% (236/404) served more than 5 years. 37.9% (153/404) had a family history of insomnia. 18.8% (76/404) did not habitually nap, 68.9% (226/328) napped for ≤30 min, 31.1% (102/328) napped over 30 min, and 18.3% (74/404) had insomnia over the past month. As for helicopter flying personnel, 75.5% (305/404) reported experiencing fatigue, with 69.1% (279/404) attributing it to flight-related factors and 51.5% (208/404) using coffee as a countermeasure.②Scale scores: the total score of PSQI was [5 (3, 7)], while the highest daytime dysfunction score was [1(0, 2)]. The total score of NASA-TLX was [39.19 (26.57, 51.97)], and the effort score was the highest [10.31(5.07, 14.60)]. The total score of MFI-20 averaged (47.28±14.88), with the mental fatigue score being the highest [(10.03±4.42)]. ③Comparisons of MFI-20 total scores: flying personnel with ≤5 years of flying experience had higher MFI-20 total scores than those with >5 years, and those with a family history of insomnia had higher scores than those without ( t=3.35, 2.44, P=0.001, 0.015). Individuals with insomnia over the past month had higher scores than non-insomniacs ( t=3.33, P=0.001). Significant differences in MFI-20 scores were observed based on nap duration ( F=19.95, P<0.001). Non-nappers had higher scores than those napping for ≤30 min ( P=0.005). Flying personnel who napped for >30 min had higher scores than those did not ( P=0.043) or napped for ≤30 min ( P<0.001). ④Correlation analysis: the total score of MFI-20 was positively correlated with sleep quality, sleep latency, sleep disturbances, hypnotic medications, daytime dysfunction, and the total score of PSQI ( r=0.118-0.226, all P<0.05), but negatively with sleep duration ( r=-0.136, P=0.006). The total score of MFI-20 was positively correlated with mental demand, physical demand, and the total score of NASA-TLX ( r=0.119, 0.168, 0.184, P=0.017, 0.001, <0.001). ⑤Multiple linear regression analysis: the determinants of flight fatigue included aircraft types ( B=-4.956, 95% CI:-8.124--1.788), nap duration ( B=3.693, 95% CI: 1.267-6.119), sleep latency ( B=2.371, 95% CI: 0.229-4.513), sleep duration ( B=-7.383, 95% CI:-10.008--4.758), daytime dysfunction ( B=5.003, 95% CI: 2.967-7.039) and physical workload ( B=0.611, 95% CI: 0.324-0.898). Conclusions:Helicopter flying personnel are vulnerable to flight fatigue, which is strongly linked to sleep quality and mental workload. It is crucial to address flying personnel′s self-perceived fatigue, care about fatigue manifestations across aircraft types, and implement targeted interventions to improve sleep quality and reduce mental workload.

Objective:To investigate the incidence of visual fatigue among military pilots during flights or simulated flights and analyze the correlations among the multidimensional evaluation indicators of visual fatigue.Methods:A total of 172 pilots from an Air Force unit were selected between March 2022 and August 2023. A self-made pilot visual fatigue scale [involving the basic information, visual fatigue status scale (VFSS), and visual quality scale (VQS) was used. The visual fatigue among pilots of different types was compared. Pearson correlation analysis was used to explore the correlations between the cumulative duration of visual display terminal (VDT) and the dimensions of the VFSS, as well as between dimensions of the VFSS and the VQS. Multiple linear regression was used to identify the determinants of the score of the VQS.Results:A total of 172 questionnaires were issued, 146 of which were valid, with an effective rate of 84.88%. Among the 146 military pilots, 73 were fighter pilots and 73 were pilots of other aircraft types (20 bombers, 5 helicopters, 36 transporters, 8 trainers, and 4 fighter-bombers). There were significant differences in the scores of various dimensions and the total score of the VFSS between pilots who were different in age, aircraft types, maximum single-sortie flight durations, and in the proportion of time spent viewing cockpit displays during flight missions ( F=4.93-14.41, t=2.37-4.86, all P<0.01 or <0.05). Significant differences in visual disturbance, systemic symptoms, environmental factors, and the total visual fatigue score were observed between pilots whose total flying hours were different ( F=14.18, 4.90, 4.66, 8.12, P<0.001, =0.009,0.011, <0.001). However, there were no significant differences in the scores of any dimension or in the total score of the VFSS between pilots with a history of ocular trauma or disease and those without (all P>0.05). The cumulative duration of VDT use was positively correlated with the scores of all dimensions and the total score of the VFSS ( r=0.353, 0.303, 0.312, 0.250, 0.356, P<0.001, <0.001, <0.001, =0.002, <0.001), the dimensions of which were positively correlated with those of the VQS ( r=0.448-0.781, all P<0.01). Age ( B=1.524, 95% CI: 0.503-2.545), proportions of time spent viewing cockpit displays during flight missions ( B=3.721, 95% CI: 1.683-5.759), starburst ( B=2.346, 95% CI: 0.516-4.176), blurred vision ( B=3.517, 95% CI: 1.168-5.866), visual fluctuation ( B=2.997, 95% CI: 1.036-4.957) and halo ( B=2.415, 95% CI: 0.469-4.362) were contributors to the total visual fatigue score. Conclusions:The scores of various dimensions and the total score of visual fatigue status in military pilots can increase with age, peak in the group ages 40 to 49, and then decline. Fighter pilots experience lower levels of visual fatigue than those of other aircraft types. The visual quality scale can serve as a reference for assessing pilots′ visual fatigue status. Cumulative durations of VDT use are positively correlated with the degree of visual fatigue. Age, proportions of time spent viewing cockpit displays during flight missions, starburst, blurred vision, visual fluctuation and halo can be used to quickly assess the risk level of visual fatigue among pilots.

Objective:To find out whether the performance of a China-made high performance human centrifuge can satisfy the need of high G training by conducting physiological experiments.Methods:The dynamic physical performance of the anti-G equipment with the human centrifuge was tested before 5 subjects underwent the gradual-onset rate (GOR) run and rapid onset rate (ROR) run experiments. The G onset rate of GOR was 0.1 G/s. The relaxed G-tolerance under GOR (GOR tolerance 1) and the anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) were tested respectively. The G onset rate of ROR was 3 G/s, and the closed-loop mode and pre-programed mode were employed respectively. The closed-loop mode involved 5 G 10 s and 8 G 10 s, where the subjects were required to manipulate the joystick to ensure that the real-time curve of the load matched the target curve. In the pre-programmed mode, the subjects were exposed to 8 G 10 s passively, without any operation requirements. A subjective evaluation form was filled out by subjects after the experiments, in which the 14 indexes for evaluation were about the gondola facilities and environment, running processes, medical monitoring and overall assessment.Results:Both the oxygen mask and anti-G suit achieved full pressurization within 2.0 s. The GOR tolerance 1 was [4.0(3.8, 4.6)] G while the GOR tolerance 2 was (6.2±0.5) G, suggesting a statistically significant difference ( Z=-2.63, P=0.008). The HP anti-G straining maneuver effect was (2.0±0.6) G. All the 5 subjects finished the 5 G 10 s experiment in a closed-loop mode. Three of them attempted 8 G 10 s in the closed-loop mode (1 subject achieved only 7.6 G peak acceleration, and the other 2 achieved full 8 G 10 s exposure), while the remaining 2 completed the 8 G 10 s in the pre-programmed mode. In the closed-loop mode, it was found that the stick force was too strong, the guiding G and real time G curve were not easy to distinguish for some of the subjects because the curve colors were similar, and that the subjects could not see the G curves clearly in case of a grayout. Both seat comfort and the voice quality of communication got the highest subjective assessment score [5.0(4.0, 5.0)] while the sensation of tumble got the lowest score (2.8±0.8). The median or mean scores of other subjective evaluation indexes ranged from 3.0 to 4.6 points. The overall score of subjective assessment was [4.0(3.5, 4.0)] points. Conclusions:The China-made high performance human centrifuge can meet the requirements of 8.0 G high G training, which can be made more effective and comfortable if the strong stick force and feeling of tumble during stop running are overcome.

Objective:To explore the differences in the ability of different parts of the human skin to recognize vibration frequencies in order to provide data for physiological optimization of vibration parameters in pilots′ tactile vests.Methods:Ten healthy volunteers were selected and grouped by age as 20-40 years (6 cases) and 41-50 years (4 cases). All the subjects participated in 3 trials: ① identification test of frequency steps using cutaneous tactile perception: the back of the left hand was chosen as the test area, a dual-oscillator synchronous vibration system was adopted, and the frequency step was gradually increased (initially 0.1 Hz) to determine the threshold of frequency identification; ② maximum frequency threshold test of cutaneous tactile perception: the maximum frequency recognition thresholds in 7 parts of the trunk (the left waist, right waist, chest, back, left shoulder, right shoulder, neck) and the back of the hand were tested; ③ frequency discrimination test of cutaneous tactile perception: 5 equally spaced frequencies (covering the frequency recognition thresholds) were set to evaluate the accuracy of tactile frequency memory on the back of the hand after 3, 15 min and 24 h. The relationships between the adjacent step sizes of cutaneous tactile perception and the average value of the sum of adjacent frequencies were analyzed using simple linear regression. The highest identification thresholds of frequencies in different parts of the subjects as well as the accuracy of frequency discrimination during different periods were compared across the age groups.Results:The maximum thresholds of frequency identification of cutaneous tactile perception among the 10 subjects ranged from 16.20 to 33.55 Hz, while the range of adjacent step sizes was between 3.60 and 7.10 Hz. The adjacent step sizes were positively correlated with the average value of the sum of adjacent frequencies ( r=0.882, F=529.18, P<0.001). In the test on the maximum threshold of frequency identification of cutaneous tactile perception, there was a statistically significant difference in the main effect of an age group between the 2 groups ( F=15.87, P<0.001), but not in the main effect of the site ( P>0.05), or in the interactions between the group and age ( P>0.05). The accuracies of skin vibration frequency memory on the dorsal hand of the subjects at 3, 15 min and 24 h were 88%, 72% and 68% respectively. In the frequency discrimination test, there were no statistically significant differences in the main effect of the group, main effect of time or in their interactions between the 2 groups (all P>0.05). Conclusions:The ability of the human skin to identify vibration frequency is impacted by age, but there is no difference in sensitivity between the trunk and the back of the hand. It is recommended that the tactile vest for pilots be designed for general purposes to make it easy to adapt to vibration frequencies of multiple parts.

Objective:To investigate the clinical characteristics and aeromedical assessment conclusions of bronchial asthma in military pilots.Methods:The clinical data of 24 military pilots was retrospectively analyzed who were diagnosed with bronchial asthma and hospitalized at the Air Force Medical Center between January 2010 and March 2024. These pilots were divided into a qualified group and a grounded group based on aeromedical assessment conclusions. The basic information, clinical data, diagnosis and treatment, and aeromedical assessment conclusions were compared between the 2 groups.Results:There were 11 military pilots in the qualified group and 13 in the grounded group. No statistically significant differences were observed between the 2 groups in terms of age at initial asthma diagnosis, body mass index, flying hours, aircraft types, smoking status, or family history of bronchial asthma (all P>0.05). The time intervals between the symptom onset, initial diagnosis and treatment and ground observation were shorter in the qualified group than in the grounded group, with statistically significant differences ( Z=-1.77, -2.73, P=0.047, 0.006). No statistically significant differences were found between the 2 groups in terms of cough variant asthma, concurrent allergic rhinitis, eosinophil count and percentage, and abnormal pulmonary function (all P>0.05). The proportion of military pilots with identified allergens was significantly higher in the grounded group than in the qualified group ( P=0.005). In the qualified group, one fighter pilot was aeromedically assessed as being restricted to dual-seat fighter aircraft. After 3 months of ground observation without disease recurrence, the dual-seat restriction was lifted. The other 2 fighter pilots were qualified for downgraded aircraft types (from fighters to bombers, transporters, or helicopters). Eight non-fighter pilots were aeromedically concluded as eligible for flight. After [43.0(15.8, 66.3)] months of treatment and ground observation, the 13 military pilots in the grounded group were found to be under poor symptom control with recurrent episodes before being grounded. Conclusions:Bronchial asthma in military pilots is closely related to allergic rhinitis, with early clinical symptoms often being atypical and prone to delayed diagnosis and treatment. Patients with bronchial asthma should receive individualized treatment based on their condition. Both the US military and the Chinese military stipulate that pilots with bronchial asthma be ineligible for flight. However, for cases with mild illness, no sudden acute severe attacks, symptom resolution after treatment, normal pulmonary function, and in stable condition after 3-6 months of ground observation, an aeromedical assessment can be conducted based on the aircraft types and flight duties.