How Much Caffeine An “Average” Sleep-Deprived Person Needs

If you’re like most Americans, the minute you find yourself yawning at your desk, you reach for a universal go-to – coffee. But, while sleep-deprived employees are definitely a thing in the US, we’ve got nothing on the men and women in the US military.

The CDC reports that average folks need about eight or nine hours of sleep each night. Most Americans log about seven. But our country’s defenders? They do well to get five hours of sleep, and that’s when they’re stationed at home. If these proud service members are on duty or in combat, then their lack of sleep is even more extreme.

Their primary self-treatment for no sleep is the same as ours – coffee. Or, they may grab other caffeine-rich drinks, like soda and energy drinks. No matter how they take it, the goal is the same:  to use caffeine to feel more awake.

With this reality front and center, scientists in the US have been studying the effects of sleep deprivation for decades. What they found may surprise you.

Researchers have compiled all of their findings into one mathematical equation that can help anyone – military or civilian – calculate the “just right” amount of caffeine they need to stay alert.

With the “caffeine calculator,” the US military has two objectives: to determine how much caffeine the “average” sleep-deprived person needs to rocket them to the same level of alertness as a person who had slept eight hours, and to determine in real time how much a certain amount of caffeine will affect a person’s level of alertness.

“How do humans respond to continuous sleep deprivation of 60 hours?” asks Dr. Jaques Reifman, one of the scientists behind the findings, located at the US Army Medical Research and Materiel Command in Fort Detrick, Maryland. “How is that different from when you sleep three hours a night for 10 days? What we’re doing here now is to develop math equations that describe the phenomenon.”

While the equation that Reifman and his colleagues developed is currently proprietary (sorry for all you with your calculators out), here are a few examples to illustrate the effect of caffeine consumption on alertness when you’re sleepy. For reference, when we refer to a “weak cup of coffee” below, we’re talking about a mug with about 100 milligrams of caffeine. (Remember, the amount of caffeine in Starbucks, Dunkin’ Donuts, and McDonald’s coffees all vary, so check the nutritional information for your favorite cup.)

If you log five hours of sleep a night, you may need to drink the equivalent of two cups of weak coffee when you wake up, followed by another two cups four hours later.

If you’re sleeping well, but you’re on the night overnight shift, you’re best off if you drink a quick two cups of weak coffee at the beginning of your shift.

If you expect not to sleep much at all for more than a day or two (think college students and exam period), then it’s suggested you drink the equivalent of two cups of weak coffee at midnight, then at 4 a.m., and again at 8 a.m.

Reifman states that the goal is to garner the maximum benefit from the caffeine you’re sipping on while ensuring the caffeine in your bloodstream doesn’t exceed the safe limit of 400 milligrams.

Stay tuned for the formula to be declassified. Reifman reports that the military is trying to license it, and then it may be available for the rest of us on the web. So, in the future, if you get the yawns at work and are curious how much coffee you need to get back to productivity, there will be an app for that.

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