Caffeine Does Wake You Up, But It May Not Improve Cognitive Function

You might be happier, but you won't perform any better. Image Credit: Just Dance/Shutterstock.com

After waking up feeling groggy and dead to the world, the immediate thing for most of us to do is reach for a cup of coffee. 

While this daily caffeine hit certainly works in lifting your spirits and becoming ready for the day ahead, new research suggests that may not actually improve cognition, leaving you open to still making errors that occur due to sleep deprivation.  

The study, involving 276 participants, compared the ability to complete tasks of varying difficulty once while awake and alert, and then once again later when they had either forced themselves to stay awake all night in the lab or gone home to sleep. Some of the participants were given a high amount of caffeine (200 milligrams) before completing the second task while others were given a placebo, and the results were compared to see whether caffeine would negate the impairment from lack of sleep. 

The results, which were published in the Journal of Experimental Psychology: Learning, Memory, & Cognition, showed that the intake of caffeine helped the group complete the task, but it did not significantly improve their task scores when compared to the control group, who were solely sleep deprived.  

“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,” Professor Kimberly Fenn, one of the paper’s authors, said in a statement.

“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.” 

It is currently unclear why sleep deprivation impairs cognitive tasks. It is well documented that sleep deprivation results in poorer working memory, attention, and decision-making, meaning it is vital for individuals who make important decisions to get their beauty sleep. This is particularly true for doctors and surgeons, whose long working hours and stressful conditions make it difficult to have adequate sleep for life-threatening surgeries. Studies looking into this discovered significantly higher mortality during surgery after-hours compared to morning surgeries, suggesting fatigue could play a role in medical outcomes. With the results above showing that caffeine may not be an effective solution to combat this, it could seriously impact the attitude towards quality sleep for workplace performance.  

“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.” 

This study doesn't say that caffeine is useless, however. It was extremely helpful in pushing the participants to complete their tasks – which is sometimes all that is required in the workplace – and it only looked at a limited set of tasks. It is possible, therefore, that caffeine can help in areas not looked at by the study, but that would require further investigation.

 


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