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image of a man pulling an all-nighter

4 Surprising Reasons Not to Pull an All-Nighter

Whether you’re cramming for an exam or preparing for an important presentation at work, it may be tempting to pull an all-nighter. But staying up and working through the night can do more harm than good.

Just ask Terry Cralle, RN, certified sleep educator, Saatva sleep consultant, and author of Sleeping Your Way to the Top. “I have three words for you: Don’t do it,” she says. “It’s so counterproductive. In terms of learning material, you’re doing the exact opposite of what you should be doing.”

You already know you won’t feel your best after a night of no sleep, but all-nighters will do more than just make you feel crummy the next day. The human brain needs rest, and staying up all night can impact your health and performance in ways you may not even realize, from your ability to concentrate to messing with your mood, and even possibly causing you to reach for junk food over healthier snacks.

Here are four reasons to avoid pulling an all-nighter—and what to do if you absolutely must skimp on sleep.

A night with no sleep can kill cognitive function

Going without sleep, even for a night, can wreak havoc on your thinking and memory skills. “Our mental performance really takes a hit,” Cralle explains. “It affects our ability to think, use good judgment, to focus, to pay attention, to react quickly.”

In fact, studies show sleep deprivation can impair your mental function as much as being intoxicated. “Definitely never get behind the wheel of a car [after a night of no sleep],” Cralle warns.

And when it comes to studying or absorbing new material, all-nighters can have the opposite of the intended effect. For example, one study published in the journal Behavioral Sleep Medicine found that college students who pull all-nighters were more likely to have lower GPAs than students who were well-rested. The study author noted that most students didn’t pull all-nighters due to procrastination—although there was also a correlation between procrastination and lower GPAs.

Related: A simple way to protect yourself against Alzheimer’s disease

An all-nighter can mess with your mood

The day after you stay up all night, you’ll probably expect to feel irritable and cranky. But a lesser-known effect of an all-nighter is short-term euphoria, which could lead to poor judgment and decision-making.

A study from UC Berkeley published in the Journal of Neuroscience finds people with severe sleep deprivation experience a short-term boost in dopamine, a neurotransmitter that regulates positive feelings, as well as cravings, sex drive, and addictive behaviors. This could lead to impulsive and potentially risky decision making following an all-nighter, according to the researchers.

Sleep deprivation may rev up your appetite

Inadequate sleep can throw off your metabolism by triggering changes in the so-called “hunger hormones.”

A study published in the journal PLOS One finds people with shortened sleep have reduced levels of leptin, the hormone responsible for the feeling of satiety, and increased levels of ghrelin, which increases appetite and can lead to cravings for sugary foods and carbohydrates. Over time, this can lead to changes in body mass index (BMI) and increased obesity risk. What’s more, studies show sleep deprivation can increase the risk of type 2 diabetes.

An all-nighter can have a snowball effect

The sleep deprivation that comes with pulling an all-nighter is not something you can quickly recover from, Cralle explains. “You don’t really bounce back for a while,” she says.

That’s because staying up all night can have a snowball effect, messing with your circadian rhythm, the natural, internal process that regulates your sleep-wake cycle. That can make it more difficult to sleep the next night and the night after, which in turn compounds all of the negative health effects that come with sleep deprivation.

Related: 14 things you can do right now for better sleep tonight

What to do if you absolutely must stay up all night

Let’s face it: There are times when the responsibilities of life may make it impossible to get a full eight hours of shuteye. Whether you have late-night meetings or events or you’re taking an overnight flight, sleep deprivation is sometimes unavoidable.

In those cases, what medical experts refer to as “anticipatory napping” or “sleep banking” can help.

“If you know a night is coming up where you will be able to get limited sleep, schedule some time for a long nap the day before,” Cralle says. “If you can extend your sleep time in anticipation for known sleep loss, I would definitely do that.”

And for people who try to convince themselves they can get by on little or no sleep? They’re in need of a bit of a wake-up call, Cralle says.

“The power of sleep is so unbelievably strong,” she says. “I think people have to be humbled and realize that all the willpower in the world to power through probably doesn’t help at all.”

Need help falling asleep? Here are 10 nighttime activities to help you relax.