If you stayed up all night catching up on Netflix or if your neighbor’s dog was too noisy and you couldn’t sleep, a big coffee in the morning is usually the way to power through the rest of the day. As it turns out, caffeine can only get you so far. 

Caffeine is a fast-acting stimulant that works on the central nervous system. It can increase blood pressure and heart rate, boost energy levels, and improve overall mood. Coffee accounts for 54% of caffeine consumption in the world, while tea accounts for another 43%. A normal dose is about 50 mg to 200 milligrams. 

We can experience the effects of caffeine right after consuming it, and the effects will continue to last for as long as the caffeine remains in your body. According to the US Academy of Sleep Medicine, caffeine’s half-life is up to 5 hours. However, many people see it as a magical cure against sleep deprivation — and that it is not.

Now, researchers from Michigan State University’s Sleep and Learning Lab looked at how effective caffeine was in counteracting the negative effects of sleep deprivation on cognition. They assessed the impact of caffeine after a night of sleep deprivation, asking 275 participants to complete a set of tasks, from simple to difficult ones. 

Participants were randomly assigned to either stay awake overnight in the lab or sleep at home. In the morning, those who slept returned to the lab, and all participants consumed a capsule that contained either 200 mg of caffeine or a placebo. After an absorption period, all participants completed simple and complex attention tasks. 

The researchers found that sleep deprivation impaired performance on both types of tasks and that having caffeine helped people successfully achieve the easier task. However, caffeine had a limited effect on performance on the complex tasks, which he participants had to be do in a specific order without skipping or repeating steps. 

“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,” Kimberly Fenn, lead author, explained the findings in a statement. “Caffeine increases energy and reduces sleepiness but it absolutely does not replace a full night of sleep.”

Fenn and her team highlighted that while people may fell that they can tackle sleep deprivation with caffeine, their performance on higher-level tasks will likely be affected – as seen in the study. This is why sleep deprivation can be dangerous. Lacking adequate sleep affects cognition, alters mood and can take a toll on immunity, they added. 

That’s why it’s important to consider other ways to naturally increase your energy levels without caffeine. Some of the following options can help: drinking more water, eating lots of plant-based food, which may provide energy, exercising daily, but not too close to bedtime, avoiding long daytime naps and getting at least 7 hours of sleep — preferably 8 or more.

“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. Instead, our findings underscore the importance of prioritizing sleep,” Fenn said. 

The study was published in the Journal of Experimental Psychology: Learning, Memory, and Cognition.