text: Sleep Readiness
  REST BREAKS (WITHOUT SLEEP)
  11-57. In addition to varying as a function of sleep loss and the circadian rhythm of alertness, performance
  also varies as a function of time-on-task. This effect—the tendency for performance on a continuously
  performed task to decline across time—is especially apparent on tasks requiring a lot of mental energy or
  extended vigilance, and it is reversed by simple time-off-task (rest). Time-on-task effects interact with (are
  exacerbated by) sleepiness. Therefore, when Soldiers perform such tasks under conditions of sleep loss or
  during the descending phase of the circadian rhythm of alertness, leaders can expect Soldiers will need more
  frequent and/or longer rest breaks. Although rest breaks reverse that portion of the performance deficit caused
  by time-on-task, such breaks do not reverse deficits associated with sleepiness per se (unless, of course,
  Soldiers get some sleep during the rest break). Sleep loss effects and time-on-task effects interactively impair
  performance but require different interventions.
  REVERSE PHYSICAL TRAINING SCHEDULE
  11-58. When it is feasible, this strategy—a delayed start time to the duty day with afternoon as opposed to
  morning physical training sessions—has two benefits. First, it conforms well to the brain’s natural circadian
  rhythm of alertness. Second, it results in longer sleep durations, especially in younger Soldiers who almost
  invariably use a later wake time to obtain more sleep. When implemented, this schedule can result in reduced
  utilization of sick call and reduced accident rates.
  CAFFEINE TO SUSTAIN ALERTNESS AND PERFORMANCE
  11-59. Table 11-2 summarizes the caffeine doses for optimal alertness under different sleep challenges.
  Table 11-2. Caffeine dose for optimal alertness
  Type of sleep challenge Dose
  Sustained operations  200 mg at midnight
   200 mg again at 0400 and 0800 if needed
   Use during daytime (1200 and 1600) only if needed
  Night operations with daytime sleep  200 mg at start of night shift
   200 mg again 4 hours later
   Late dose: at least 6 hours prior to start of daytime sleep
  Restricted sleep (6 hours of sleep)  200 mg upon awakening
   200 mg again 4 hours later
   Last dose: at least 6 hours prior to sleep period
  mg milligram
  Caffeine Dose (200 milligrams)
  11-60. For many missions some degree of sleep loss is unavoidable. In these cases, Soldiers may best
  accomplish short-term sustainment of alertness and performance with judicious use of a non-sleep (stimulant)
  intervention. For a variety of reasons (including its wide availability, its familiarity to Soldiers, and its relative
  safety and effectiveness), caffeine is recommended for this purpose. For most individuals under most
  circumstances, the optimal dose of caffeine is 200 milligrams.
  Caffeine Limitations
  11-61. Caffeine only temporarily helps restore alertness and performance. It does not replace sleep. Nor
  does it fully restore all the cognitive abilities decremented by sleep loss. In much the same way, caffeine can
  help keep a Soldier from falling asleep, but it does not improve that Soldier’s judgment, coordination, or
  reaction time. Because it will interfere with the ability to initiate and/or maintain sleep, Soldiers should avoid
  caffeine, if consistent with mission requirements, for at least 6 hours prior to an anticipated sleep opportunity.