Sleep Duration, Chronic Insomnia, and Subjective Sleepiness in a Sample of Professional Flight Crews — SOMNAVI  

Sleep Disorder Clinical Trial

Official title: Sleep Duration, Chronic Insomnia, and Subjective Sleepiness in a Sample of Professional Flight Crews

Status Not yet recruiting

Clinical Trial Summary

Sleep is a physiological function that plays an essential role in many somatic, cognitive and psychological processes. Although there are many criteria for the effectiveness of sleep, its quantity is unanimously recognized as a major determinant of health. Too little sleep is associated with an increase in metabolic, cardiovascular and accidental morbidity and mortality caused by drowsiness while traveling or at work.

Today, the time devoted to sleep is in competition with the time devoted to work, transport or new technologies, in a professional or recreational context. Faced with the public health issues thus raised, research has highlighted the interest of studying the relationships between sleep time and socio-demographic factors, beyond the mere involvement of sleep pathologies. However, among these pathologies, the role of insomnia is not negligible: it is in fact the most frequent sleep disorder (16% of French people in 2010) and represents an important source of involuntary reduction in sleep time, likely to increase inappropriate sleepiness during periods of wakefulness, in the context of activities sometimes involving safety.

Flight crews are exposed to specific operational constraints, both in civilian and military environments, which may compromise the sleep recovery function (operational fatigue, extended work amplitudes, repetition of jet lag, etc.). These constraints, which are conducive to compromising the required levels of alertness and cognitive performance, are also at risk of cardiometabolic complications. They therefore raise the issue of risk control and maintenance of air safety.

The issue of fatigue in pilots remains an essential issue for the safety of flight operations. Several determinants of operational fatigue in air transport have been identified, such as irregular sleep schedules, large, irregular, and sometimes unpredictable activity amplitudes, sleep debt, night flying, and circadian disruptions related to multiple and repeated time zone changes. While these factors have to deal with rules within airlines that are more often based on "work/rest" than "sleep/wake", current legislation and regulations in the aviation industry are now moving towards scientific approaches to fatigue management in commercial aviation, emphasizing the importance of sleep and taking circadian rhythms into account.

In the wake of recent work carried out in the general French population, the conduct of a specific study on sleep time, prevalence and factors associated with chronic insomnia and the complaint of drowsiness among aircrew appears relevant. Due to the specific operational constraints mentioned above, chronic insomnia and sleep debt can be assumed to be more frequent among sailors than in the general population. A better consideration of certain sleep disorders in professional aircrew could allow the adaptation of prevention strategies or countermeasures aimed at optimizing the control of risks with regard to flight safety.

Clinical Trial Description

Sleep is a physiological function that plays an essential role in many somatic, cognitive and psychological processes. Although there are many criteria for the effectiveness of sleep, its quantity is unanimously recognized as a major determinant of health. Too little sleep is associated with an increase in metabolic, cardiovascular and accidental morbidity and mortality caused by drowsiness while traveling or at work.

Today, the time devoted to sleep is in competition with the time devoted to work, transport or new technologies, in a professional or recreational context. Faced with the public health issues thus raised, research has highlighted the interest of studying the relationships between sleep time and socio-demographic factors, beyond the mere involvement of sleep pathologies. However, among these pathologies, the role of insomnia is not negligible: it is in fact the most frequent sleep disorder (16% of French people in 2010) and represents an important source of involuntary reduction in sleep time, likely to increase inappropriate sleepiness during periods of wakefulness, in the context of activities sometimes involving safety.

Flight crews are exposed to specific operational constraints, both in civilian and military environments, which may compromise the sleep recovery function (operational fatigue, extended work amplitudes, repetition of jet lag, etc.). These constraints, which are conducive to compromising the required levels of alertness and cognitive performance, are also at risk of cardiometabolic complications. They therefore raise the issue of risk control and maintenance of air safety.

The issue of fatigue in pilots remains an essential issue for the safety of flight operations. Several determinants of operational fatigue in air transport have been identified, such as irregular sleep schedules, large, irregular, and sometimes unpredictable activity amplitudes, sleep debt, night flying, and circadian disruptions related to multiple and repeated time zone changes. While these factors have to deal with rules within airlines that are more often based on "work/rest" than "sleep/wake", current legislation and regulations in the aviation industry are now moving towards scientific approaches to fatigue management in commercial aviation, emphasizing the importance of sleep and taking circadian rhythms into account.

Currently, the vast majority of studies devoted to the sleep of aviation flight crews is therefore limited to commercial airline pilots. They have established that most flights, especially on long-haul sectors, involve circadian rhythm disturbances, sleep fragmentation and sleep restriction that are deleterious to cognitive performance and the risk of accidents. Most of the publications have sought associations between sleep measures and performance in operational contexts. Some have shown that conventional methods of assessing sleep in flight (actimetric readings, sleep diaries or subjective self-reporting) were correlated with reference data obtained by polysomnography, strongly for sleep duration but moderately to weakly for its effectiveness. In the specific case of sleep duration, self-report questionnaires have been shown to be a reliable alternative to in-flight actimetric measurements.

The majority of studies have been designed with pilot sleep as a determinant of in-flight performance, especially during long (12 to 16 hours) and very long (more than 16 hours) flights. On the other hand, consideration of the consequences of aeronautical activity on pilot sleep is relatively rare in the scientific literature. Thus, most "ecological" studies, known as field studies, generally focus on specific flights with restricted time slots and small sample sizes, limiting the scope of the results regarding the effects of flights on sleep. Currently, the main focus is still on pilot sleep immediately before, during, and after duty, but without characterizing the baseline sleep observed during off-duty periods.

In this perspective, one study looked at the baseline sleep of airline pilots, making comparisons to samples of the general North American population [28]. Out of a total of 332 long-haul pilots, actimetric data revealed longer sleep times during rest periods, highlighting the influence of environmental constraints considered to be a health risk. Furthermore, the influence of socio-demographic and occupational parameters was reported in a study of 435 pilots. The high prevalence of sleep disorders, drowsiness and fatigue were documented, as well as an increased risk of fatigue for aircrew engaged on short and medium-haul flights, in connection with work schedule amplitudes and repetition of rotations.

In the wake of recent work carried out in the general French population, the conduct of a specific study on sleep time, prevalence and factors associated with chronic insomnia and the complaint of drowsiness among aircrew appears relevant. Due to the specific operational constraints mentioned above, chronic insomnia and sleep debt can be assumed to be more frequent among sailors than in the general population. A better consideration of certain sleep disorders in professional aircrew could allow the adaptation of prevention strategies or countermeasures aimed at optimizing the control of risks with regard to flight safety. ;

Related Conditions & MeSH terms

• Sleep Disorder
• Sleep Initiation and Maintenance Disorders
• Sleep Wake Disorders
• Sleepiness

• NCT number: NCT04761809
• Study type: Observational
• Source: Direction Centrale du Service de Santé des Armées
• Contact: Nicolas HUIBAN, MD
• Phone: 483162265
• Email: nicolas.huiban@intradef.gouv.fr
• Status: Not yet recruiting
• Start date: March 2021
• Completion date: August 2021