Don’t Count on Caffeine to Fight Sleep Deprivation

Summary: A caffeine jolt may give you a little more energy following a restless night of sleep, but it doesn’t necessarily help with boosting cognition. Researchers found that while caffeine helped sleep deprived students to perform better at some simple cognition tests, it had no effect on improving performance on more challenging tasks, like placekeeping tests.

Source: Michigan State University

Rough night of sleep? Relying on caffeine to get you through the day isn’t always the answer, says a new study from Michigan State University.

Researchers from MSU’s Sleep and Learning Lab, led by psychology associate professor Kimberly Fenn, assessed how effective caffeine was in counteracting the negative effects of sleep deprivation on cognition. As it turns out, caffeine can only get you so far.

The study — published in the most recent edition of Journal of Experimental Psychology: Learning, Memory, & Cognition — assessed the impact of caffeine after a night of sleep deprivation. More than 275 participants were asked to complete a simple attention task as well as a more challenging “placekeeping” task that required completion of tasks in a specific order without skipping or repeating steps.

Fenn’s study is the first to investigate the effect of caffeine on placekeeping after a period of sleep deprivation.

“We found that sleep deprivation impaired performance on both types of tasks and that having caffeine helped people successfully achieve the easier task. However, it had little effect on performance on the placekeeping task for most participants,” Fenn said.

She added: “Caffeine may improve the ability to stay awake and attend to a task, but it doesn’t do much to prevent the sort of procedural errors that can cause things like medical mistakes and car accidents.”

This shows a cup and coffee beans
Fenn’s study is the first to investigate the effect of caffeine on placekeeping after a period of sleep deprivation. Image is in the public domain

Insufficient sleep is pervasive in the United States, a problem that has intensified during the pandemic, Fenn said. Consistently lacking adequate sleep not only affects cognition and alters mood, but can eventually take a toll on immunity.

“Caffeine increases energy, reduces sleepiness and can even improve mood, but it absolutely does not replace a full night of sleep, Fenn said. “Although people may feel as if they can combat sleep deprivation with caffeine, their performance on higher-level tasks will likely still be impaired. This is one of the reasons why sleep deprivation can be so dangerous.”

Fenn said that the study has the potential to inform both theory and practice.

“If we had found that caffeine significantly reduced procedural errors under conditions of sleep deprivation, this would have broad implications for individuals who must perform high stakes procedures with insufficient sleep, like surgeons, pilots and police officers,” Fenn said. “Instead, our findings underscore the importance of prioritizing sleep.”

About this caffeine and sleep research news

Source: Michigan State University
Contact: Caroline Brooks – Michigan State University
Image: The image is in the public domain

Original Research: Closed access.
Caffeine selectively mitigates cognitive deficits caused by sleep deprivation” by Stepan, M. E., Altmann, E. M., & Fenn, K. M. Journal of Experimental Psychology: Learning, Memory, and Cognition


Caffeine selectively mitigates cognitive deficits caused by sleep deprivation

Sleep deprivation impairs a wide range of cognitive processes, but the precise mechanism underlying these deficits is unclear. One prominent proposal is that sleep deprivation impairs vigilant attention, and that impairments in vigilant attention cause impairments in cognitive tasks that require attention.

Here, we test this theory by studying the effects of caffeine on visual vigilant attention and on placekeeping, a cognitive control process that plays a role in procedural performance, problem solving, and other higher order tasks.

In the evening, participants (N = 276) completed a placekeeping task (UNRAVEL) and a vigilant attention task (the Psychomotor Vigilance Task [PVT]) and were then randomly assigned to either stay awake overnight in the laboratory or sleep at home. In the morning, participants who slept returned to the lab, and all participants consumed a capsule that contained either 200 mg of caffeine or placebo. After an absorption period, all participants completed UNRAVEL and PVT again.

Sleep deprivation impaired performance on both tasks, replicating previous work. Caffeine counteracted this impairment in vigilant attention but did not significantly affect placekeeping for most participants, though it did reduce the number of sleep-deprived participants who failed to maintain criterion accuracy.

These results suggest that sleep deprivation impairs placekeeping directly through a causal pathway that does not include visual vigilant attention, a finding that has implications for intervention research and suggests that caffeine has limited potential to reduce procedural error rates in occupational settings.

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