Here’s how much caffeine you need, and when, for peak alertness


MANY people groggily pour a cup of coffee in the morning to wake themselves up. But exactly how much caffeine should you consume — and when should you take it — to achieve “peak” alertness? A new algorithm aims to answer that question.
The algorithm, developed by U.S. Army researchers, takes into account people’s sleep schedules and identifies how much caffeine they should consume, and when, to achieve optimal alertness.
The researchers found that, by using this algorithm, they could improve people’s performance on an attention task by up to 64 percent, even though people were consuming the same total amount of caffeine as they did before. (The algorithm may recommend, for example, a specific amount of caffeine at one time, and then a different amount later in the day.) The study also found that, by following the algorithm’s dosing schedule, people could reduce their caffeine consumption by up to 65 percent, and still achieve the same level of performance.
“We developed algorithms that work together, and they essentially allow us to determine, at the individual level, when and how much the individual should take caffeine to achieve peak performance at the desired time, for the desired duration,” said study senior author Jaques Reifman, director of the DoD Biotechnology High Performance Computing Software Applications Institute at the U.S. Army Medical Research and Materiel Command in Fort Detrick, Maryland.
For example, if you’re a student who has been sleep-deprived for the last week while cramming for an upcoming exam, the algorithm aims to tell you when to take caffeine “so you are as alert as possible during the exam,” Reifman told Live Science.
The researchers have already used their technology to develop a web-based tool and a smartphone app, called 2B-Alert, which can predict a person’s alertness based on their sleep time and caffeine consumption. The web tool provides a result for the “average Joe,” while the smartphone app learns over time how an individual responds to sleep deprivation and caffeine, Reifman said.
Currently, the publicly available version of 2B-Alert doesn’t tell people when and how much caffeine to take to achieve peak performance. This aspect of the work is still being validated in studies on U.S. soldiers.
Ultimately, although the work is being developed for the military, Reifman hopes it can also benefit the lay public, including shift workers, air traffic controllers and even students cramming for a test.

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