Pushing through the night to study, work, or respond to an emergency can feel downright heroic. You did what you had to do, against the odds.
But once the adrenaline wears off and daylight comes, you may suddenly be a little unsteady on your feet. Surviving the day after an all-nighter can be more difficult than it was to stay awake in the first place.
A night of sleep deprivation affects your brain -- how quickly you can react, how well you can pay attention, how you sort information or remember it. In fact, studies have shown that after an all-nighter, you may be functioning at a similar level as someone who is legally drunk.
Brace for a Morning Slump
You may feel the worst effects just as the next day is beginning.
“You would think you would be the most impaired the longer you’re awake, but that is not the case,” says sleep expert David Dinges, PhD, chief of the division of sleep and chronobiology at the University of Pennsylvania and editor of the journal SLEEP.
Because of the natural flow of your body clock, or circadian rhythm, “you’re actually at the worst 24 hours after your habitual wake-up time," Dinges says. "You’ll have an unbelievably difficult time staying awake and alert.”
That is also the worst time for you to get in a car to drive home. “If you stayed up all night, you should not be driving, period. You are impaired,” says Mark Rosekind, PhD, a fatigue management expert who is now a member of the National Transportation Safety Board. The monotony of the road, combined with your sleep deprivation, can cause you to fall asleep uncontrollably, he says. In a 2005 poll by the National Sleep Foundation, more than a third of adult drivers admitted having nodded off at the wheel.
Brain Will Help You Through
If you need to continue to work, your brain will try to compensate for the sleep deprivation.
In a study using functional magnetic resonance imaging (fMRI), 16 young adults who had not slept for 35 hours completed tasks of increasing difficulty. Activity increased in several regions of the brain, as they essentially summoned more “brain power” than they needed when they were well-rested.
“[Sleep-deprived people] can call on cognitive resources they have that they normally don’t need to use to do a certain task. That allows them to perform reasonably well, but they still don’t perform at normal levels,” says researcher Sean P.A. Drummond, PhD, associate professor of psychiatry at the University of California San Diego and the VA San Diego Healthcare System.
Your body clock also will give you a periodic boost, as it triggers a wake signal in your brain. You may feel a second wind in the mid-morning (around 10 a.m.) and again in the early evening (at 6 p.m. or 7 p.m.). “You may feel better, but you’re still likely to be forgetful, slower to react, and less attentive," Dinges says.
Fortunately, there are some things you can do to improve your alertness and make it through the day after.
Take a Nap
The antidote to sleeplessness is sleep, says Rosekind, who led a fatigue management program for the National Aeronautics and Space Administration (NASA). In a study led by Rosekind, pilots on transpacific flights who napped for an average of 26 minutes had 34% fewer performance lapses and were half as likely to show signs of physiologic sleepiness.
Even a nap as short as 10 minutes can benefit you, as your brain quickly moves into slow-wave sleep, Dinges says. If you sleep longer than about 40 or 45 minutes, you may feel groggy when you wake up. This is called sleep inertia, and happens when you wake from a deep sleep. Once you shake off that feeling, you’ll benefit from the nap and feel sharper than you would have without it, Dinges says.
Drink Coffee or Another Caffeinated Beverage
Be strategic with your coffee or energy drink and you’ll get an extended boost in alertness. Most people need about 100 milligrams (mg) to 200 mg of caffeine, depending on their body weight, Rosekind says. (Coffee has about 100 mg of caffeine in a 5-ounce cup, though the content varies based on the strength of the brew.) Over-the-counter caffeine pills also are available in 100 mg or 200 mg doses.
It takes about 15 to 30 minutes for you to feel the effect of the caffeine, and the benefit will last for three to four hours, Rosekind says. “If you plan strategically to use the caffeine every few hours, you can keep yourself at a pretty good level of performance,” he says.
The best strategy: Have your caffeine and lie down for a 30-minute nap. You’ll wake up feeling refreshed, he says.
One caveat: When you finally stop drinking your caffeinated beverage, expect a crash. “The caffeine masks the sleepiness, [but] the sleepiness just keeps building up,” Rosekind says.
Turn Up the Light
Your body clock is attuned to the cycle of darkness and light, so bright light has an alerting effect.
“As people get more and more tired, they often find bright light unpleasant and they’ll deliberately turn the light off,” says Dinges. Instead, you should turn lights on and even step out into the sunshine, Drummond says.
Move Your Body
Taking a brisk walk or working out gets your blood moving. Exercise also boosts your brain power. “If you move your body, there’s automatic feedback from your muscles that goes to the central mechanism of the brain to improve alertness,” says Sharon Keenan, PhD, founder and director of the School of Sleep Medicine of the Stanford University Center for Excellence for the Diagnosis and Treatment of Sleep Disorders.
Even changing your activity or being engaged in a conversation can improve alertness, Rosekind says. But as soon as you stop the activity or conversation, you’re likely to feel sleepy again, he says.
After a night without sleep, your working memory is impaired. That means you can’t keep as many things in your mind at one time, Drummond says.
A study of 40 young adults who had 42 hours of sleep deprivation -- equivalent to staying up all night and the next day until a late bedtime -- showed a 38% decrease in working memory capacity. Imaging studies confirmed that the part of the brain involved in integrating information isn’t as active in people who are sleep deprived.
Know Your Limitations
You may try to snap yourself awake by splashing cold water on your face or opening a window or making the room a bit cooler. You may feel better after taking a shower and dressing up for a new day. But there’s no way to trick your body and mind. That refreshed feeling is destined to be followed by a slump.
“The biological drive for sleep is so great that you just can’t cheat it,” Drummond says. “It is as important for life as water and oxygen and food.”
There’s good news at the end of an all-nighter. Once you finally get to sleep again, you will sleep more deeply than usual, with more slow-wave sleep. “It's better to sleep until you just naturally wake up,” says Dinges, which means you may sleep 9 or 10 hours. That will be the true recovery from your sleepless night, he says.