What Pulling an All-Nighter Does to Your Mind

Six ways all-nighters do more harm than good, according to the science.

Image by Adobestock / Freeslab

If you’re considering staying up all night, it’s probably because you need to get something important done. Between hectic schedules and ever-increasing work demands, most of us have, at some point or another, felt like we’ve had to burn the midnight oil in order to finish a project, prep for a meeting, or study for an exam.

True, once in a rare while, a super tight deadline or a touch of procrastination may mean that you feel the need to stay up until the wee hours to get stuff done. But when you do, you probably won’t do your best work—and you will definitely end up paying the price the next day.

Here’s six surprising ways that pulling an all-nighter could end up doing more harm than good—and why you should take steps to avoid them at all costs.

1. You’ll retain less information.

Most of us pull all-nighters when we don’t feel prepared for something big that’s happening the next day. It could be memorizing lines in a speech or important presentation, reading up on important details for a big meeting or client, or even cramming for a test.

The thinking is that if you put more time in, you’ll be more likely to know the material inside and out. But when it comes to remembering important information, staying up later might actually mean learning less.

That’s because snoozing plays a critical role in the formation of new memories, according to findings published in the journal Science. During deep sleep, your brain is actually hard at work growing connections between brain cells that work to help turn short-term memories into long-term ones.

Skip that crucial down time, and you might find it tough to recall what you were cramming in the first place. Research suggests your sleepy mind may even be prone to making up false memories and erroneous information.

2. Facts won’t make as much sense.

Just because you’re up at 4 AM reading and reviewing, say, project guidelines for a major new client, doesn’t actually guarantee that you’re understanding what they mean. In fact, your brain might not really know what to do with the information that you’re taking in until you’ve had some time to snooze on it.

Skeptical? You shouldn’t be. When participants in one recent British study were taught rules for how to use words in a fictional language, they were unable to apply the rules to help them understand new words after they had slept.

That’s because your brain needs slumber to make sense of new information and figure out how to use it in a meaningful way. So while you might remember the three key objectives that your client wants to achieve and can repeat them word for word, you probably won’t be able to apply them to your new project outline until you’ve caught 40 winks.

3. You’ll have a tougher time coming up with fresh ideas.

On first thought, the middle of the night sounds like the perfect time for a brainstorming blowout. There’s practically nothing around to distract you, and it might be the only time when you don’t feel like you need to be doing something more outwardly productive. (After all, who has precious hours during the day to just sit around and think?)

It’s true that most of us have probably had that rogue brilliant idea come to us out of nowhere at 3 AM. But typically, sleep deprivation actually isn’t so great for creativity.

Instead, research shows that you need REM sleep—the deep sleep during which dreams tend to occur—in order to form novel associations between different pieces of information that can aid in problem solving or the development of new ideas.

4. You’ll have a harder time thinking on your feet.

Need to be able to think on your feet tomorrow? If you stay up all night, that probably won’t happen, since sleep deprivation messes with your ability to make split-second decisions.

In a recent University of Texas study, researchers pitted sleep-deprived West Point cadets against well-rested ones by having both groups perform identical tasks that required fast-decision making. The cadets who’d missed out on sleep completed the tasks with 6% less accuracy compared to those who’d caught enough zzzz’s.

And while a measly 6% might not sound like that much, consider this: One Stanford University study found that people who are mildly to moderately sleep deprived short show the same impairments to their reaction time as people who are legally drunk.

5. You’ll be in a bad mood.

If you’re staying up all night to get ready for something big, chances are you need to be upbeat, peppy, and generally “on” in the morning. But if you haven’t slept, you’ll probably be anything but.

That’s because sleepless nights tend to cause irritability, stress, and a short temper. In fact, one University of Pennsylvania study found that participants who logged 4.5 hours of sleep per night for a week reported feeling more stressed, angry, sad, and mentally exhausted than usual. But when they got back to their normal sleep schedule, their moods returned to normal, too.

And if you regularly prioritize work over sleep, you could be setting yourself up for deeper problems. Research shows that chronic insomnia can increase the risk for depression and anxiety by as much as fivefold, and can up the odds for developing a panic disorder by as much as twenty-fold.

6. You’ll probably feel a little crazy.

Crankiness isn’t the only possible side effect of pulling an all nighter. Sleep deprivation can also cause short-term euphoria. Which, at first, might not seem like such an awful thing.

But in fact, those sorts of manic highs could result in poor judgment, suggests one recent University of California-Berkeley study.

When you miss out on sleep, the parts of your brain that feel and respond to pleasure actually get a big boost (which might explain why sugary or fatty junk food seems especially delicious when you’re exhausted). But those same neural pathways are also the ones that are responsible for engaging in risky behavior.

How risky? Consider this: The findings actually led researchers to recommend that people in high-stakes professions and circumstances take steps to ensure that they get enough sleep to avoid making potentially rash decisions.

From memory to mood (and even to your appearance and weight), there are quite a few reasons to pass on all-nighters and very few reasons to make them a habit.

Working on time management strategies is helpful for long-term. But, when you do find yourself with more work than hours in the day, the best thing to do is get your work wrapped up at a reasonable time and stick to your regular sleep pattern as closely as possible. Study the most important points, then come back to it in the morning. If you’re cramming early in the day or in the afternoon, taking a quick nap afterwards might also help boost retention.

Do you notice a drop in efficiency or performance after an all-nighter? What do you find helps boost your brainpower when deadlines beacon?