text: Chapter 11
  PROMOTING HEALTHY SLEEP
  11-17. Good sleep is essential for optimal performance and readiness. Factors to consider when optimizing
  sleep duration and continuity include: the sleep environment, a pre-sleep routine, and a sleep schedule that
  conforms as closely as possible to the brain’s natural circadian rhythm of alertness.
  SLEEP ENVIRONMENT
  11-18. Sleep duration and continuity are optimized in environments that are quiet, dark, and maintained at
  a comfortable ambient temperature. Some individuals believe that they sleep better with music or a television
  on, that they can sleep anywhere, and that ambient noise does not bother them. Research clearly shows that
  this is not the case. Soldiers do not get good sleep on a cot in the tactical operations center. Although sleepers
  are not aware of it, environmental sounds cause brief arousals—a momentary speeding of the brain’s electro-
  encephalograph (known as EEG) activity during sleep—that effectively disrupt sleep continuity and reduce
  the restorative value of that sleep. Likewise, bright lights and excessively hot or cold environments can
  disrupt sleep continuity and reduce the restorative value of sleep.
  PRE-SLEEP ROUTINE
  11-19. Stress is incompatible with sleep. Pre-sleep routines that promote winding down—such as listening
  to soothing music, reading, or taking a warm shower or bath—30–60 minutes prior to bedtime tend to
  facilitate the transition to sleep. These routines will maximize sleep duration. Conversely, activities such as
  watching television, playing video games, chatting online, and similar interesting or engaging activities tend
  to arouse the brain and delay sleep onset. These activities reduce the amount of sleep obtained and should be
  avoided during the pre-sleep wind-down period. Tobacco product use is also antithetical to sleep. People
  smoke before sleep to wind down. The stimulant in nicotine tells the body to get active while it increases
  heart rate and alertness. Those experiencing significant stress often find relaxation techniques such as
  meditation and mindfulness exercises helpful.
  SLEEP SCHEDULE
  11-20. Adequate performance is best achieved by Soldiers who consistently get adequate sleep (7–8 hours)
  on a nighttime sleep-daytime wakefulness schedule aligned with the brain’s natural circadian rhythm of
  alertness. Both sleep duration and sleep continuity are maximized on such schedules. However, military
  operations are often continuous (24-hours per day) and influenced by random and unpredictable events and
  requirements. Shift work is unavoidable for at least some deployed Soldiers, and sleep opportunities are
  sometimes unpredictable for virtually all deployed Soldiers. The following situations commonly contribute
  to sleep loss and decrements in waking performance:
  * Shift work.
  * Changing schedules.
  * Social jet lag.
  SHIFT WORK
  11-21. The human brain is biologically hard-wired to be alert during the daylight hours and asleep during
  the nighttime and early morning hours. Because of this, poor quality sleep results from night shift work even
  when shift workers spend adequate time (approximately 8–9 hours) in bed during the daytime. Although such
  a schedule is unnatural for the human brain, some adaptation to a nighttime-awake and daytime-asleep
  schedule does occur over time, but such adaptation is never complete. Soldiers always pay a cost in their
  waking performance and daytime sleep quality. This occurs even when working consistent, steady nights. In
  the long term, Soldiers associate frequent shift work with weight gain and increased risks for diabetes, fatty
  liver disease, and cardiovascular disease. See discussions beginning in paragraphs 11-24 and 11-30 for
  strategies to mitigate adverse effects of shift work.