“Caffeine simply cannot replace a night of sleep, and it is critical that individuals prioritize sleep and if they must endure a night without sleep, that they take the necessary precautions and avoid driving a car or performing any high-stakes tasks,” Fenn said.
To get a better idea of what caffeine can, or can’t, do in the face of sleep loss, researchers asked more than 275 people to complete a simple attention task as well as a more challenging one that required them to complete tasks in a specific order without skipping or repeating steps. The latter is known as a place-keeping task.
Folks either stayed awake overnight in the lab or slept at home. In the morning, all participants consumed a capsule that contained either 200 milligrams (mg) of caffeine or placebo and completed both tasks again. (An 8-ounce cup of regular coffee may contain 75 to 120 mg of caffeine.)
Sleep loss impaired performance on both tasks. Caffeine helped people successfully achieve the easier task, but not the more difficult one, the study found.
“If you are sleep-deprived, using caffeine will only help you with reaction time, not with being able to remember the steps you need to do in a procedure, “said Michael Breus, a sleep medicine expert and clinical psychologist in Los Angeles. He has no ties to the new study.
