What to Know About Sleep Deficiency

LAST UPDATED: June 15, 2018
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Our brains cannot function without sleep. You can’t train your brain to do more with less sleep and there are no shortcuts, not even taking in more caffeine. The brain only works as well as the amount of sleep it is fed. Remember, “Sleep is ammo for your brain.” The more you get, the more mentally sharp your brain and YOU will be.

Purposely going without adequate sleep

Purposely going without enough sleep is often seen as a sign of strength (and needing sleep a sign of weakness)—but when you don’t get enough sleep there is a tendency to become irritable, distracted, and stressed more easily. The ability to perform your mission, do well at school, work, or home improves when you get the right amount of sleep. With adequate sleep, productivity increases, your energy improves, and you think more clearly while being more efficient at work.

Problems getting to sleep or staying asleep (Insomnia)

Problems sleeping, is one of the most common complaints among Soldiers, particularly those who return from deployment. From 2000 to 2009, the diagnosis of insomnia in active duty Army personnel increased 19-fold. This is significant because insomnia is associated with anxiety, depression, PTSD, chronic pain, alcohol abuse, and even with suicide.

We all have either seen someone or been that person who did not get enough sleep the night before. You tend to look tired, be a bit grumpy, and choose your caffeinated beverage of choice to “get going.” People who get insufficient sleep are less motivated, less likely to make healthy food choices, are less active, and less productive.

Signs of inadequate sleep

The best way to evaluate an individual’s status is to observe his or her behavior. Indications of inadequate sleep include:

  • Struggling to stay awake during briefings, classes, etc.
  • Difficulty understanding or tracking information
  • Lapses in attention
  • Decreased initiative or motivation
  • Irritability

Or, ask the obvious question: “How much sleep have I had over the last 24 hours?” Leaders should also ask themselves this question.

Consequences of sleep deficiency

Common short term consequences of sleep deficiency include:

  1. Decreased physical and mental performance
  2. Impaired memory
  3. Impaired concentration
  4. Decreased reaction time
  5. Poor decision-making
  6. Decreased testosterone production
  7. Diminished emotional control

Over the long term, insufficient sleep has been linked to increased risk for developing several medical conditions such as obesity, diabetes, hypertension, and cardiovascular disease.

Insufficient sleep also impairs one’s ability to self-monitor. This means a person who is sleep-deprived tends to overestimate their ability to function. This is the same for Soldiers and leaders. Their own proficiency is overestimated under sleep-deprived conditions. This is because the ability to self-monitor also relies on sufficient sleep. These physiologic deficits cannot be overcome by motivation, initiative, or willpower—and can only be TEMPORARILY overcome by caffeine.

Sleep, performance and safety

The so-called “adrenaline rush” experienced during combat or training does not offset insufficient sleep. A sleep deprived Soldier might shoot a “friendly,” enter the wrong coordinates, or give the wrong dose of medicine. In general, sleep-deprived Soldiers have a higher potential to make wrong tactical decisions and this could mean the difference of life or death. For these reasons, leaders must prioritize sleep for their Soldiers AND themselves.

Soldiers who routinely get less than 7 hours of sleep perform much like a person who is legally drunk. They lose their situational awareness, lose the ability to exercise good judgment and increase risky behaviors. They also are at risk of uncontrolled and unintentional sleeping. Micro-sleep can occur during critical events such as driving, speaking and even walking. Put simply, accidents increase when the total amount of sleep you get each night decreases overtime.

Common combat tasks compromised by insufficient sleep

These include (but are not limited to):

  • Requesting indirect fire
  • Detecting and appropriately determining threat level
  • Coordinating squad tactics
  • Combat activity such as firing from bounding vehicle and observing the terrain for enemy presence

Drowsy driving

According to the National Highway Traffic Safety Administration (NHTSA), fatigue-related crashes are the leading cause of “fatal to the driver” truck crashes. According to the Center for Disease Control (CDC), approximately 25% of motor vehicle accidents are related to drowsy driving.

The total number of the sleep-deprived crashes are equal to the number of drug and alcohol related crashes put together. This means drowsiness is the principal cause in at least 100,000 police reported traffic crashes each year, killing more than 1,500 Americans and injuring another 71,000.

In one survey, adults who reported unintentionally falling asleep during the day, were more likely to fall asleep when driving, snore, and slept less than, or equal to 6 hours per 24 hour period. The most common drowsy drivers are men, young drivers, binge drinkers, and people who rarely or never wear seatbelts. Adults between 18–24 years old are more likely to drive drowsy than any other age group and therefore are at high risk for being killed in drowsy driving-related accidents.

Based on safety data collected by the Army from FY 11 until August of 2014, 569 Soldiers were killed or injured in accidents that mostly occurred during the day as a result from fatigue. The emotional cost of these fatigue-related accidents is huge and the dollar estimate is approximately $3.5M. This is almost half of the cost of all accidents in the Army during the same timeframe.

Sleep debt and performance

The demanding nature of military operations often creates situations in which obtaining enough sleep on a regular basis is difficult or impossible. Such chronic, insufficient sleep (anything less than 7–8 hours per 24 hours) produces a sleep debt—a chronic state of sleep need characterized by impaired performance and readiness. The rate at which the sleep debt (and performance deficits) grows depends upon how much nightly sleep is restricted and how much sleep an individual needs. The only way to eliminate the debt is to get sleep.

How much sleep do I need?

To determine how much sleep your body needs, certain conditions must exist to get the best picture possible. First, pick a time when there are no restrictions such as during a vacation or during an extended period of time off from work. Do the following to understand how much sleep you really need:

  1. Sleep until you feel rested and restored
  2. Repeat this until you can wake up without an alarm
  3. Once you know how many hours you need, begin to establish a sleep routine with the same sleep and wake times.
  4. Ensure you practice good sleep habits (see Bedtime Routine).

Sleep debt

A sleep debt occurs when you get less sleep than you need. You can recover recent sleep loss by going to bed a little earlier each night. It is impossible to train your brain to function better with less sleep. There are no shortcuts for sleep. Your brain only work as well as the amount of sleep you feed it; the more sleep you get, the more mentally sharp you are. You cannot recover sleep lost as a result of chronic sleep deficiency in only one or two nights. The best recommendation for someone in this situation is to get as much sleep possible until the sleep need becomes stable. You will know this when you start thinking better, acting better and having more energy.

Performance decrement across days of insufficient sleep

The following figure shows the relationship between hours of sleep per night and performance. You can use this chart to gauge the impact of nightly sleep duration on performance. As shown, anything less than 7–8 hours of good-quality sleep per 24 hours negatively impacts performance—impairment increases as nightly sleep duration decreases.

Performance decrement measured in percent of normal cognitive performance

5 days/8 hours sleep = 100% performance, 6.5 hours = 90%, 5 hours = 80%, 3 hours or 2 days of no sleep = 70%

With 7–8 hours of sleep per 24 hours, Soldiers sustain optimal performance for the entire waking day (Green zone).

When Soldiers get less than 7–8 hours of sleep, performance degrades over time. Getting 4–6 hours of sleep every 24 hours will keep Soldiers in the Amber zone (90% to 85% performance) for several days, then they fall into the Red zone (85% to 50% performance). Getting less than 4 hours of sleep guarantees that Soldiers immediately fall into the Amber Zone and quickly progress into the Red Zone.

Less than 5% of Soldiers can sustain performance on less than 7–8 hours sleep per 24 hours. If a Leader is in this 5% group, it may be difficult to understand that most Soldiers are not in this group—and to foster a unit environment where 7–8 hours is considered normal. 

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