https://crsreports.congress.gov
Updated November 18, 2022
Management of Sleep and Fatigue in Military Aviation
In recent years, Congress has expressed concern over 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 these effects, 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 32.5% of adults do not meet the Healthy People
2030 (HP2030) criteria for sufficient sleep. In comparison,
the 2018 DOD Health Related Behaviors Survey estimated
77.7% of active duty servicemembers did not meet HP2030
criteria. HP2030 categorizes sufficient sleep as at least
seven hours in a 24-hour period. Research indicates a
variety of detrimental health effects arise from both acute
and chronic sleep deprivation.
Sleep deprivation and fatigue are two distinct physiological
states. The National Institutes of Health defines sleep
deprivation as a condition that occurs when someone “[does
not] get enough sleep.” Sleep deprivation is a contributor to
fatigue. The National Institute for Occupational Safety and
Health 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 apparent during the early morning
hours (see Figure 1).
Figure 1. Relative Level of Alertness and Wakefulness
Based on Time of Day
Source: CRS graphic adapted from Shappell, et al., Crew Rest and
Duty Restrictions for Commercial Space Flight, available at
https://rosap.ntl.bts.gov/view/dot/34244.
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 described the “risk of accident in training,
operational, and combat environments significantly
increases if Service members are sleep deprived.”
Fatigue Management in Military Aviation
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 consistently
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 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 military
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, the Air Force and Navy have authorized the use of
pharmacological measures for select missions and aircrew
during combat operations, at least since the Vietnam War.
The operational needs for these measures have been
scrutinized and are an area of review. For example, the Air
Force suspended the use of stimulants between 1996 and
2001. After considering survey results from pilots flying
during Operation Desert Storm and four placebo-controlled
studies, the Air Force validated the need and utility of the
measures and rescinded the suspension.
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
