What staying up all night does to your brain
Anna Rothschild | TED-Ed • Nov 2024

You're just one Roman Empire history final away from a relaxing spring break. But you still have so much to study! So you decide to follow in the footsteps of many students before you and pull an all-nighter.

When you stay up all night, you're fighting against your body's natural circadian rhythms. These are the cyclical changes that virtually all living things experience over the course of a 24-hour period— such as sleeping and waking— and they're heavily influenced by light. But for the moment, you're alert and powering through the rule of Julius Caesar.

As the sun sets, your eyes send signals about the dwindling light to a part of your brain called suprachiasmatic nucleus. This is basically your circadian rhythm's clock. It alerts your pineal gland to start producing melatonin. That's the hormone that helps prepare your body for sleep, and levels start to rise about two hours before your normal bedtime. At the same time, neurons in the hypothalamus and brain stem release a compound called GABA. This slows down activity in your brain and can have a calming effect.

You're approaching your normal bedtime. Since the brain needs to cool down before sleep, your core body temperature starts to drop.

Huh, that map kind of looks like a face. Uh-oh, your attention has started to drift. Throughout the day, your brain has been releasing a waste product called adenosine. The more adenosine latching onto receptors in your brain, the more tired and inattentive you become. Time for a cup of coffee. Caffeine blocks adenosine from binding to receptors, which can give you a boost of energy. However, it might also make you jittery and increase your anxiety.

You're acing these flashcards! Right now these dates and names are being stored in an area of the brain called the hippocampus. Normally when you go to sleep, memories like these are consolidated and slotted into long-term storage in your brain's neocortex. So it's a good thing you only need to remember this information through tomorrow.

Microsleeps are unpredictable periods of sleep that last for only a few seconds and are triggered by sleep deprivation. You stretch in an attempt to stay awake. But at this point your motor skills have also taken a hit. Studies have found that people who have been awake for 19 hours have similar coordination and reaction times as those who have been drinking.

As the sun rises, your pineal gland stops releasing melatonin. You feel a "second wind" come on. And despite everything, you leave for school in a really good mood. Sleep deprivation can briefly induce euphoria. It's caused a temporary boost in dopamine levels, which can unfortunately also lead to poor choices.

The final starts off well. It's all multiple choice! But then you get to the essay portion. It's thought that during sleep, our brains process ideas and draw connections between new memories and old ones. So your sleepless brain might be able to regurgitate facts, but you're finding it more difficult to find patterns or problem solve. You stare at the blank page, defeated.

You head up to your room, anxious and irritable. Your amygdala, the part of the brain involved with processing emotion, is going haywire. Your prefrontal cortex usually keeps your amygdala in check, but it still isn't firing on all cylinders. Your bed has never felt so sweet.

After one sleepless night, your body and brain bounce back pretty quickly. Which is a good thing since we can't always control how much sleep we get. But going for long periods without a good night's sleep or constantly changing your bedtime, can take its toll. Regularly getting less than seven hours of sleep each night is linked to all sorts of health issues, from diabetes to stroke to chronic pain. It also leaves you more vulnerable to developing mental health issues like depression.

Your sleep schedule can even affect your grades. Studies have shown that college students who keep regular sleep hours have, on average, a higher GPA than students who don't. So the next time you're thinking of pulling an all-nighter, remember that Rome wasn't built in a day, or for that matter, one night.


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