The consequences of chronic sleep deprivation are far worse than one sleepless night. But the decision to pull an all-nighter just once can leave some serious damage in its wake.
The first signal that your body is overtired will be a sluggish mind. Your reaction time will begin lagging around hour 18; after a full night without sleep, it will nearly triple—which, for context, is about the same as being legally drunk. Your ability to form memories will start deteriorating, and after a while, your capacity to create any new memories at all will shut off entirely.
“It’s almost as though without sleep, the memory inbox of the brain shuts down,” Matthew Walker, a UC-Berkeley professor and author of Why We Sleep, told Business Insider. “So those new incoming informational emails are just bounced.”
Stay up longer than 24 hours and your brain, now in panic mode, will soon take over and force sleep upon you. “You’re basically going to have microsleeps,” Feinsilver says. Though you will appear to be awake—walking, talking, eyes open—your brain will quite literally put itself to sleep for ten to 20 seconds at a time.
During these microsleeps, you can’t process what you’re seeing
Stay up for longer than 35 hours and your emotional mind will start behaving irrationally. When you’re up for that long, the emotion-emitting amygdala becomes 60 percent more reactive to negative stimuli or experience, while also limiting communication with the part of the brain that regulates emotion and contextualizes experiences. In other words, you’re more reactive and judgmental to the people and events around you, and your brain loses its natural ability to run things through a filter or any internal voice of reason.