Soldiers stay awake through a combination of caffeine, strategic napping, stimulant medications, light exposure, and dietary tactics, all layered together depending on the mission. The U.S. military has spent decades studying sleep deprivation and has developed specific protocols that go well beyond willpower and coffee.
Caffeine Gum: The Fastest Tool in the Kit
The most widely used alertness aid in the military is caffeine, but not in the form most people imagine. The Department of Defense developed a product called Stay Alert gum, a cinnamon-flavored gum with 100 milligrams of caffeine per piece, roughly equal to a six-ounce cup of coffee. The advantage over drinking coffee is speed: caffeine absorbed through the tissues of the mouth reaches the brain in about five minutes, compared to 20 to 25 minutes for coffee swallowed and digested through the stomach.
That difference matters when a soldier needs to go from groggy to functional in minutes. Each pack contains five pieces, and the delivery method means troops can dose precisely without needing hot water, a mug, or any prep time. Caffeine works by blocking a chemical signal in the brain that builds up during waking hours and makes you feel sleepy. Military nutrition researchers have found that doses of 300 to 600 milligrams produce the desired alertness boost in people who aren’t regular caffeine users, though habitual coffee drinkers need more to get the same effect.
Prescription Stimulants for Extended Missions
For missions lasting 24 hours or longer, particularly in aviation, the military has authorized pharmaceutical stimulants. Pilots have historically used dextroamphetamine, commonly known as “go pills,” in 10-milligram doses taken up to three times during a mission. These are closely regulated, voluntary, and tracked by flight surgeons.
A newer option, modafinil, was approved for some bomber missions at a 100-milligram dose. Testing found it was less effective than three doses of dextroamphetamine, but it carries fewer side effects and lower abuse potential. These medications aren’t handed out casually. They’re reserved for scenarios where sleep is physically impossible, such as long-range bombing runs or sustained air operations, and their use requires medical oversight and documentation.
Sleep Banking and Tactical Naps
Staying awake effectively starts before the mission begins. The Army’s Warfighter Fatigue Management guide recommends “sleep banking,” which means sleeping 10 hours per night in the days leading up to an operation. The idea is to build a surplus of rest that the body can draw on when sleep becomes scarce. Research supports this: people who oversleep before a period of deprivation perform measurably better than those who enter it on a normal schedule.
During sustained operations, the guidance calls for tactical naps whenever possible. Even five minutes of sleep can provide a small recovery benefit, and a 20-minute nap can restore several hours of alertness. Soldiers are trained to grab sleep in fragments, treating rest as a tactical resource rather than a luxury. This is a shift from older military culture, which often treated sleeplessness as a badge of toughness.
Despite these recommendations, the reality often falls short. The Department of Defense recommends at least seven hours of sleep per night for optimal performance. Yet for over a decade, DOD surveys have found that the majority of service members report sleeping six hours or fewer, even during non-combat periods.
Blue Light Exposure
Light is one of the strongest signals the brain uses to determine whether it’s time to be awake or asleep. Military researchers have explored blue-light-emitting glasses as a non-drug method to suppress melatonin, the hormone that triggers drowsiness. These glasses contain small LEDs in the frame that emit light at about 461 nanometers, a wavelength particularly effective at telling the brain it’s daytime.
Wearing them for 30 consecutive minutes during the first half of a night shift can produce measurable alerting effects. For troops on rotating or overnight schedules, this offers a way to push back the body’s internal clock without pills. The approach is borrowed from shift-work research and is still being refined for field conditions, but it represents a growing interest in non-pharmacological tools.
Food and Nutrients That Affect Alertness
What soldiers eat also plays a role. A military nutrition research committee identified four substances with strong evidence for sustaining performance during sleep loss: caffeine, carbohydrates, tyrosine, and choline.
- Carbohydrates are most useful during continuous physical activity lasting more than 90 minutes, extending the time before exhaustion sets in. However, meals with a high ratio of carbohydrates to protein actually increase drowsiness, which is why combat rations are designed to balance the two.
- Tyrosine, an amino acid found in meat, eggs, and dairy, has been shown to reduce the mental effects of cold, low oxygen, and psychological stress. It helps maintain cognitive function when the body is under physical strain.
- Choline, found in eggs, liver, and soybeans, enhances memory and reaction time. The committee recommended further testing for soldiers in high-stress environments, noting it’s safe even at high intake levels.
These nutrients don’t replace sleep, but they help the brain function closer to baseline when rest isn’t available. Combat rations are formulated with these findings in mind, balancing macronutrients to avoid the post-meal crash that a carb-heavy meal would cause.
Measuring Who’s Too Tired to Perform
One challenge the military faces is that sleep-deprived people are notoriously bad at judging their own impairment. To address this, researchers use the Psychomotor Vigilance Task, a simple reaction-time test. A soldier watches a screen and presses a button the moment a stimulus appears. The test measures three things: how fast they respond on average, how often they have extremely slow reactions (longer than 500 milliseconds, called “lapses”), and how variable their responses are from one trial to the next.
Sleep loss doesn’t just make people slower. It makes them inconsistent, with stretches of normal performance interrupted by complete attention failures. The test also catches “false responses,” where someone presses the button when nothing appeared, a sign that executive function and impulse control are degrading. This kind of testing helps commanders make decisions about whether someone is fit for duty, particularly in roles like piloting or operating heavy equipment where a single lapse can be fatal.
How It All Fits Together
In practice, soldiers don’t rely on any single method. A typical approach layers multiple strategies: sleep banking in the days before deployment, caffeine gum during the first night of operations, tactical naps whenever a window opens, controlled lighting to manage the body’s clock, and balanced nutrition to avoid energy crashes. Stimulant medications sit at the top of the pyramid, used only when nothing else is sufficient and the mission demands it.
The military’s approach has evolved significantly from the “push through it” mentality of earlier decades. Sleep deprivation degrades reaction time, decision-making, emotional regulation, and physical coordination in ways that directly compromise mission success. The current framework treats fatigue as a tactical threat on par with enemy action, something to be managed systematically rather than simply endured.