The U.S. Army's new health and fitness manual is officially endorsing an activity for sustaining mental alertness that soldiers have always practiced unofficially: nap time.
Whether they are sitting in the back of tightly packed military aircraft, Bradley Fighting Vehicles or resupply trucks, soldiers will always catch their Z's while they can, especially during lulls in continuous training and combat operations.
Now the Army's new field manual for Holistic Health and Fitness recommends that leaders create time for soldiers to take short naps during long periods of continuous operations when troops are getting less than six hours of sleep a night.
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"When regular nighttime sleep is not possible due to mission requirements, soldiers can use short, infrequent naps to restore wakefulness and promote performance," according to the manual. "When routinely available sleep time is difficult to predict, soldiers might take the longest nap possible as frequently as time is available. During periods of restricted sleep ... napping combined with appropriate doses of caffeine may help to sustain cognitive performance and alertness."
The new manual, dated October 2020, revises the Army's 2012 version of the manual to build "peak performance" in soldiers who "must be able to fight and win in both defensive and offensive operations that occur without notice."
Linking sleep to cognitive performance is not new. In late 2018, the Navy issued new guidance to ensure sailors serving on aircraft carriers the chance to have eight hours of uninterrupted sleep per 24-hour period. That action followed two separate and deadly accidents in 2017 involving the USS Fitzgerald and USS John S. McCain colliding with commercial ships. Human error and sleep deprivation were cited in the Navy's investigation of the incidents.
"Soldiers and leaders frequently ask, 'what is the minimum amount of sleep needed to maintain military effectiveness?'" the Army's updated manual states. "There is no clear threshold amount of sleep below which effectiveness is compromised and above which effectiveness is sustained. Most Soldiers need 7 to 9 hours of sleep every 24 hours to maximize health and sustain performance."
Soldiers are unlikely to get such prolonged periods of sleep on extended combat missions or during intense combat training scenarios such as three-week long decisive action rotations at the National Training Center in Fort Irwin, California.
Army Ranger School exposes soldiers to 61 days of mentally and physically exhausting training, which often means Ranger candidates get just two to three hours of sleep in a 24-hour period for several days at a time.
"The notion that one can adapt to sleep loss is a myth," according to the new manual. "Although soldiers generally benefit from training as they fight, this does not hold true for sleep loss. Soldiers cannot be trained to perform better on less sleep."
The only possible benefit to training under conditions of sleep loss is a potential increase in soldiers' "awareness and appreciation for the extent to which sleep loss impacts their physical and mental abilities," the manual states.
"Most soldiers who regularly obtain less than 7--8 hours of sleep every 24 hours pay a price: they unwittingly but steadily accrue a significant sleep debt, characterized by increasingly suboptimal alertness, reduced mental sharpness, and an impaired ability to recover from stress," it continues. "These soldiers typically believe that they are fine and may perform most basic duties adequately. From an objective standpoint, their alertness and mental acuity is significantly (and invariably) impaired."
Leaders should consider soldier sleep as important as the resupply of ammunition, fuel, water and food, according to the guidance, which adds that they should create a rest plan for soldiers that features time for short naps when soldiers are getting less than six hours of sleep every 24 hours for prolonged periods.
"Give soldiers permission to nap when circumstances allow, and encourage naps when appropriate, especially during continuous operations," the manual states. "Take naps whenever possible to accumulate 7-8 hours of sleep in every 24-hour period."
Leaders also need to ensure that operational or training environments should be safe and secure for soldiers to grab a quick nap, the manual states.
Caffeine, taken in the right doses and times can help maintain alertness, but it can also be counterproductive and interfere with opportunities to sleep, the manual states. The optimal dose of caffeine is 200 milligrams, which is equivalent to two cups of coffee.
"Soldiers should avoid caffeine, if consistent with mission requirements, for at least 6 hours prior to an anticipated sleep opportunity," according to the manual.
In reality, there are no shortcuts -- only sleep can replace lost sleep.
"Soldiers should sleep as much as they can, whenever they can, as the situation allows," the manual states.
-- Matthew Cox can be reached at matthew.cox@military.com.
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