Aerospace medicine and human performance最新文献

Introduction: Symptoms related to elevated carbon dioxide (CO2) concentrations on the International Space Station are widely stated and researched. While microgravity contributes to the observed CO2 related symptoms, an additional factor that may contribute to symptoms associated with hypercapnia is the impact of environmental CO2 on sleep. Studies evaluating how the sleep environment impacts sleep quality in terrestrial environments have shown that slightly elevated CO2 concentrations can negatively impact deep sleep quantity.

Methods: CO2 concentrations in the crewmembers' sleep quarters and crew sleep quality were recorded during two simulated space missions at the Integrated Lunar/Mars Analog Habitat. Both objective sleep stage data and perceived sleep quality were collected and correlated with environmental CO2 concentrations, temperatures, and reported health symptoms using sleep actigraphy, a perceived sleep questionnaire, and daily health surveys.

Results: In a space analog environment with CO2 concentrations from 450-2000 ppm, higher nightly CO2 concentrations correlated with reduced deep sleep times. However, intersubject linear regression showed varying results. Habitat temperatures had significant influence on the crew's sleep and reported health symptoms.

Discussion: During the 2-wk analog missions, the reductions in deep sleep when nightly CO2 concentrations increased were consistent with other terrestrial sleep studies. Due to the small sample size and variations between subjects, the evidence is not sufficient to draw definitive conclusions. This study can inform the risk analysis of environmental CO2 concentration requirements for future space habitats and provide recommendations for further research. Van Hoy SE. Environmental carbon dioxide and temperature effects on sleep quality during space analogs. Aerosp Med Hum Perform. 2026; 97(1):11-19.

Background: Growing access to and use of chest CT has increased the incidental detection of solitary pulmonary nodules. In the Republic of Singapore Air Force, three such cases of its servicemen with solitary pulmonary nodules were recently deliberated at its Aeromedical Board between July and November 2024. While one proved to be the first case of lung adenocarcinoma diagnosed among Republic of Singapore Air Force aircrew, the histological diagnoses obtained in the remaining two servicemen were of a much less common nature. This article discusses their clinical presentation, management, and eventual aeromedical disposition.

Case series: The first case is of an Air Traffic Controller diagnosed with a pulmonary carcinoid following detection of an incidental nodule on chest CT. The second case describes an unmanned aerial vehicle pilot who was found to have pulmonary mucosa-associated lymphoid tissue after an abnormal routine chest x-ray.

Discussion: With greater use of chest CT, flight surgeons are more likely to encounter and manage the incidental detection of solitary pulmonary nodules among aircrew. Apart from a greater familiarity with current management guidelines for pulmonary nodules, it may be timely for aeromedical professionals to have an increased awareness of their differential diagnoses and how their possible histological outcomes may impact a return to aviation-related duties. Low JW. Two cases of incidental pulmonary nodules and rare lung neoplasms. Aerosp Med Hum Perform. 2025; 96(12):1090-1093.

Introduction: A study of British military rotary-wing pilots was conducted using actigraphy-driven fatigue modeling to identify groups of pilots at increased risk of fatigue.

Methods: Pilots were recruited across the three military services of the United Kingdom. Objective fatigue was predicted using wearable actigraphy and the Sleep Activity Fatigue Task Effectiveness (SAFTE) fatigue model. Subjective data were collected from daily questionnaires, including descriptions of workplace activities and subjective assessments of the subjects' fatigue levels, using Samn-Perelli scores. An assessment was then made of the relationship between their workplace activities and their subjective and objective fatigue levels.

Results: There were 38 men and 2 women recruited. The mean age was 36.4 yr (SD ± 6.5, range 26-52 yr). A total of 200 flights were undertaken, with a mean flight time of 156 min (±77.1, range 15-480). SAFTE scores were shown to decline for night-flying, declining strongly after 22:00. Pilots deployed on exercise were more likely to be subjectively and objectively fatigued, regardless of the timing of their flights. Pilots cohabiting with infants under 1 yr of age were more likely to suffer fatigue decrements than those who did not. The data suggest that inexperienced pilots find their flights more subjectively fatiguing than their instructors, but more work is needed in this domain.

Discussion: Biomathematical fatigue modeling such as SAFTE has a role in military rotary-wing aviation. Consideration should be given to its use in night-flying, flights undertaken when deployed, and for those cohabiting with infants. Pelham A, Van Tongeren M, Arnold H, Cocco P. Identifying military rotary-wing pilots at increased risk of fatigue using biomathematical modeling. Aerosp Med Hum Perform. 2025; 96(12):1043-1049.

Introduction: Fatigue from multiple sources (e.g., circadian, workload, stress, etc.) can create a compound safety risk. Pilots operating medium haul (M-H) routes may be susceptible to compound fatigue, but sources of fatigue in M-H operations have not been robustly quantified.

Methods: In an anonymous survey, airline pilots working M-H rosters were asked to rank on a scale of 0-10 the level of fatigue they experience from 40 separate factors across four domains: 1) circadian; 2) environmental; 3) operational; and 4) psychosocial, with higher scores indicating more fatigue. Pilots also reported habitual sleep duration.

Results: A total of 223 pilots (90 Captains; 133 First Officers) completed the survey. Pilots rated circadian factors as most fatiguing [mean (SD); 6 (1)], followed by factors in the psychosocial and environmental domains [both 5 (1)], and finally, the operational domain [4 (2)]. Pilots reported sleeping 7 h on average; sleep was not significantly related to fatigue ratings.

Discussion: Operational fatigue factors related to higher work volume (e.g., working longer hours, shorter breaks, etc.) were rated as more fatiguing. Schedule features that impinge on the window of circadian low (e.g., early starts, late ends) were fatiguing even in M-H pilots with daytime schedules that allow for sufficient sleep duration. Devine JK, Hursh SR, Behrend J. Compound fatigue risk in medium-haul pilots. Aerosp Med Hum Perform. 2025; 96(12):1063-1068.

Introduction: Accommodative dysfunction is one of the factors leading to asthenopia. By analyzing the changes of visual function and visual quality before and after wearing night-vision equipment, this study explored the factors influencing visual fatigue in military pilots during night-vision training, so as to provide a basis for alleviating visual fatigue in night-vision environments and provide help for targeted optimization of training programs.

Methods: This research recorded the basic data of 20 military pilots who participated in night-vision training. These military pilots underwent night-vision training with night-vision equipment. A questionnaire (supplemental Appendix A, found in the online version of this article) was used to record the relevant information of visual function before and after training. SPSS25.0 statistical software was used for data analysis.

Results: The sample consisted of 20 male military pilots with an average age of 32.8 yr (32.8 ± 5.03). Of the 40 eyes, 15 (37.5%) showed some degree of myopia regulation, although there was no significant difference in refractive indexes such as refractive type, spherical equivalent, or spherical equivalent difference after training. There was a significant difference in the interpupillary distance before and after training, and the difference was statistically significant only in the group aged 35 yr or older.

Discussion: Military pilots undergoing night-vision training experience varying degrees of visual strain. In this study, subjects tended to have reduced interpupillary distance after training. Also, those aged under 35 yr were more likely to have regulation-related visual fatigue, while those aged 35 yr or older were more likely to have convergence-related visual fatigue. Wang H, Zhao Y-Y, Wu T-Y, Wang X, Zhao C-F, Lu C, Zhang M, Liu Y. Visual fatigue factors associated with night-vision training among military pilots. Aerosp Med Hum Perform. 2025; 96(12):1050-1055.

Introduction: Military pilots are routinely exposed to environmental stressors such as hypoxia, dry air, and G-forces, which may affect pulmonary function. Although spirometry is performed regularly to assess flight fitness, the long-term effects of flying on lung function remain unclear.

Methods: This retrospective study analyzed data from the Center for Man in Aviation of the Royal Netherlands Air and Space Force, encompassing two parts. First, all medical assessments from 2012 to early 2025 were reviewed to determine how often pilots were declared unfit to fly due to abnormal spirometry. Second, a Generalized Estimating Equation model was used to assess the effect of cumulative flight time, smoking status, and age on the forced expiratory volume in 1 s/vital capacity (FEV1/FVC) ratio using data collected between 2012 and mid-2019 (before the adoption of standardized Z-scores).

Results: Out of 9182 assessments, 3 pilots were deemed unfit to fly solely due to an abnormal spirometry. In the Generalized Estimating Equation analysis of 4558 assessments, flight hours showed a nonsignificant trend toward a positive, albeit clinically irrelevant, association with FEV1/FVC. There was no significant difference between aircraft types or between former and never-smokers. FEV1/FVC declined significantly with age and was significantly lower in current smokers compared to never-smokers.

Discussion: Pulmonary abnormalities rarely led to unfit declarations and no evidence was found for a negative long-term effect of military flying on pulmonary function. Age and smoking status were significant predictors of FEV1/FVC decline. These findings may inform future refinement of pulmonary assessment protocols for military pilots. Konings M, Wiekenkamp AC, Wingelaar-Jagt YQ, Wingelaar TT. Evaluating the impact of flight hours on pulmonary function in military pilots. Aerosp Med Hum Perform. 2025; 96(12):1079-1083.

Introduction: Intense light exposures can cause temporary flash blindness, degrading pilot performance during flight. The present study investigated factors influencing time to recover from flash blindness for tasks resembling aircraft control using an attitude indicator. Prior similar studies of flash blindness used only reflective gauges whereas modern cockpits include emissive displays, so recovery differences between reflective and emissive instrument types were of interest as was the influence of varying ambient luminance levels.

Methods: Nine subjects performed attitude indicator horizon stabilization and tracking tasks on both a reflective and an emissive attitude indicator. Subjects were exposed to short (150 ms) high intensity broadband light flashes at three retinal exposure levels [6.5, 7.0, and 7.5 log troland-seconds (logTd·s)] beforehand. Additionally, ambient luminance was manipulated (1 cd · m-2, 10 cd · m-2, and 100 cd · m-2). The time to level the horizon after a flash exposure was measured. After leveling, roll and pitch errors made while maintaining straight and level flight by countering added perturbation were also tracked.

Results: Greater flash intensity usually increased recovery time. For the reflective attitude indicator, as ambient luminance increased, flash intensity had weaker influence on recovery times, with recovery times ranging from 6-30 s. For the emissive attitude indicator, however, ambient luminance did not appreciably influence recovery times, with recovery times ranging from 8-16 s.

Discussion: The reflective attitude indicator was more advantageous for flash blindness recovery in high (100 cd · m-2) ambient luminance and the emissive indicator was relatively more advantageous in low (1 cd · m-2) ambient luminance. Arizpe JM, McAnally RE, Hart MV, Kuyk TK, Smith PA, Goettl BP. Flash blindness recovery of a tracking task on cockpit attitude indicators. Aerosp Med Hum Perform. 2025; 96(12):1032-1042.

Introduction: At high concentrations 2-butanone is an irritant that may cause central nervous system effects. In 1996, NASA established spacecraft maximum allowable concentrations (SMACs) for short-duration, off-nominal scenarios at 50 ppm based on human exposure data from the 1940s. Limits for 7, 30, and 180 d were set at 10 ppm using the same data, but accounting for the small number of volunteers and extrapolation from mild effects to no effects for nominal operations. Limits were not established for missions of 1000 d.

Methods: A literature search was conducted of toxicity studies of inhalation exposure to 2-butanone published since the original SMACs were developed. Additionally, studies cited in the development of existing occupational limits, acute exposure guidelines, and state permitting and monitoring limits were assessed.

Results: Several toxicity studies published after SMACs were established in 1996 are summarized here. Many of the studies evaluated whether the existing occupational limit of 200 ppm is adequate to protect workers.

Discussion: As part of a periodic review of historical limits, SMACs were revised for all durations for 2-butanone. Acute SMACs were increased from 50 ppm to 200 ppm. The SMAC for 7 d was increased from 10 ppm to 67 ppm, and the SMACs for 30 and 180 d were increased from 10 ppm to 22 ppm. A SMAC for 1000 d has now been set at 22 ppm. Limits based on the most recent evidence and risk assessment methodologies will ensure the appropriate degree of conservatism in future spacecraft design. Ryder VE. Revisions to spacecraft maximum allowable concentrations for 2-butanone. Aerosp Med Hum Perform. 2025; 96(12):1094-1097.