The following is the May 13, 2025, Congressional Research Service In Focus report, Management of Sleep and Fatigue in Military Aviation.
From the report
Over the past decade, Congress has expressed interest in the effects of sleep deprivation on servicemember health and military readiness, as well as its impact on military aviation safety. Aviators in all military services of the Department of Defense (DOD) with high operational, psychological, and physiological demands may experience sleep deprivation and fatigue. To counter potential effects of sleep deprivation and fatigue, the military services use mitigation strategies (i.e., non-pharmacological and pharmacological measures) to enhance aviator safety and prevent aviation mishaps. This In Focus provides an overview of those mitigation strategies and offers issues for congressional consideration.
Background
The U.S. Centers for Disease Control and Prevention estimates that nearly one in three adults do not get enough sleep, nor meet the Healthy People 2030 (HP2030) criteria for sufficient sleep (i.e., at least seven hours of sleep per day). In comparison, the most recently available data from the 2018 DOD Health Related Behaviors Survey estimated 64.3% of active duty servicemembers did not meet HP2030 criteria. In 2021, DOD reported that 14% of active duty servicemembers were “diagnosed with at least one sleep disorder.” Research indicates a variety of detrimental health effects arise from sleep deprivation and fatigue.
Sleep deprivation and fatigue are two distinct physiological states. The National Institutes of Health define sleep deprivation as a condition that occurs when someone “[does not] get enough sleep.” Sleep deprivation is a contributor to fatigue. The National Library of Medicine defines fatigue as a “feeling of weariness, tiredness or lack of energy.” Sleep deprivation and fatigue can be most apparent when an individual is awake counter to their circadian rhythm (i.e., during the circadian trough of alertness), typically during the early morning hours.
Military aviators may experience sleep deprivation and fatigue due to a variety of factors, including inhospitable sleep environments, operational demands, unpredictable schedules, long-duty days or flight durations, challenging flight conditions, and circadian-rhythm disruption due to crossing multiple time zones, known as chronodisruption. In a March 2021 report to Congress, DOD stated sleep deprivation has “significant effects on the physical, cognitive, and emotional functioning needed for readiness, occupational, and operational mission fulfillment.” The report also stated, “[r]isk of accident in training, operational, and combat environments significantly increases if Service members are sleep deprived.”
Fatigue Management in Military Aviation
DOD Instruction 1010.10 directs department leaders to “[h]elp prevent and mitigate the effects of sleep deprivation among Service members.” Each military service is responsible for implementing its own policies and procedures to mitigate aviator fatigue and sleep deprivation. The military services use varied approaches to mitigate aviator fatigue, including (1) administrative and behavioral (i.e., non-pharmacological) measures, and (2) the voluntary use of pharmacological measures. Regulations for each service emphasize non-pharmacological measures as the primary means of mitigating fatigue.
Administrative and Behavioral Measures
Administrative and behavioral measures vary by service and airframe, but all military services limit the length of an aviator’s duty day, total flight hours over a given period, and standards for rest and time available for sleep. The services also educate aviators on the impact of sleep loss and the benefits of consistent sleep.
Pharmacological Measures
Historical Use of Pharmacological Measures. The U.S. military historically has approved pharmacological measures for aviators in certain mission contexts. For example, since at least the Vietnam War, the Air Force and Navy have authorized the use of pharmacological measures for select missions and aircrew during combat operations. The operational need for these measures and comparative effectiveness with non-pharmacological measures have been the subject of debate in modern warfare.
Current Use. Sustained high-operations tempo over the past several decades, among other factors, has generated persistent demand for the use of pharmacological measures. The military services authorize aviation medicine specialists (i.e., flight surgeons) to prescribe U.S. Food and Drug Administration (FDA)-approved pharmacological agents as a fatigue management measure when administrative and behavioral measures are known or expected to be insufficient.
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