Pulling the occasional all-nighter can seem like the only choice when you're overwhelmed, but sacrificing sleep causes more problems than it solves.
The longer you go without sleep, the more your body and brain start to struggle. Your reactions slow down, emotional responses become disproportionate, and your attention span almost disappears.
Eventually, your body takes sleep into its own hands, forcing microsleeps to accommodate for your lack of rest.
"Sleep is not optional; it is a fundamental need, as critical as food or water," explains Dr. Leah Kaylor, licensed clinical psychologist specializing in sleep and trauma. "When it is withheld, the consequences are devastating."
What is long-term sleep deprivation?
Long-term sleep deprivation is when you regularly get less sleep than your body needs. This can occur over the course of weeks, months and even years.
Sleep deprivation has a negative physical and emotional impact, as your body and brain aren't getting the recovery time needed.
While seven to nine hours is the recommended amount of sleep for an adult, our actual sleep needs vary from person to person. This means there's no exact number of hours to avoid sleep deprivation.
However, if you regularly wake up fatigued and fall asleep as soon as your head hits the pillow, you might be experiencing sleep deprivation.
Guinness World Records notes the longest a person has gone without sleep is 453 hours (close to 19 days). although due to the inherent risk of sleep deprivation, the record is no longer monitored.
When we asked Dr. Leah Kaylor about the 'health risks of long-term sleep deprivation', she emphasized the dangers of missing sleep: "[Sleep deprivation] isn’t just a personal health matter; it’s a safety issue — for yourself and others."
Dr Leah Kaylor Ph.D. PLLC is a licensed clinical psychologist specializing in sleep and trauma, at the Federal Bureau of Investigation. Dr. Kaylor completed her residency at the Memphis VA Medical Center, where she worked in the sleep clinic helping veterans with sleep hygiene, nightmares, insomnia, and CPAP adherence. Her upcoming book The Sleep Advantage explores sleep deprivation and sleep health.
How long can you go without sleep?
24 hours without sleep: "Far from harmless"
Many of us have pulled the occasional all-nighter, justifying the lack of sleep as a necessary sacrifice. But how bad is it to go without sleep for a full day?
"Staying awake for 24 hours straight might not cause long-term health problems, but it’s far from harmless," advises Dr. Kaylor.
"When you miss an entire night of sleep, your brain and body start to struggle," says Dr. Kaylor. "Your alertness drops, your attention span shortens, and your ability to make decisions or process complex information weakens."
The Centers for Disease Control and Prevention (CDC) notes that going without sleep for 24 hours is similar to having a blood alcohol count of 0.10% — that's higher than the legal drinking limit in the US (0.08%.)
"This comparison is eye-opening," notes Dr. Kaylor, "especially for those who pride themselves on pushing through exhaustion."
36 hours without sleep: "Your body is in crisis mode"
An all-nighter doesn't just mean 24 hours without sleep, as you'll often find you don't get a proper chance to rest until the next evening.
By this point you'll be pushing 36 hours without sleep — and the problems you're experiencing after 24 hours awake will intensify.
"After 36 hours without sleep, your body begins to rebel in ways that are hard to ignore," explains Dr. Kaylor. "The overwhelming urge to sleep becomes almost unbearable."
With growing "sleep pressure" comes an increasing risk of microsleeps: a brief moment of unconsciousness that can happen even when you're occupied. They're particularly dangerous if you're driving or operating machinery.
"Missing 36 hours of sleep isn’t just uncomfortable; it’s a clear signal that your body is in crisis mode, urging you to rest before further damage occurs," says Dr. Kaylor.
48 hours without sleep: "Survival mode"
Dr. Kaylor describes staying awake for 48 hours as a "monumental challenge," pushing the body into "extreme sleep deprivation."
"At 48 hours without sleep, your mind and body are in survival mode," explains Dr. Kaylor.
Sleep pressure is intense and microsleeps start coming frequently. You're likely to find it increasingly hard to resist the urge to drift off.
Dr. Kaylor notes that after 36 hours without sleep, some people start to hallucinate — by 48 hours, your mental fatigue can create a feeling of "depersonalization" and you might experience paranoia.
"Perceptual distortions can make ordinary sounds, sights, or sensations feel unnervingly strange," explains Dr. Kaylor. "Emotional stability is another casualty of prolonged sleeplessness."
"Your sense of time starts to unravel. This temporal disorientation can leave you confused about how much time has passed or even what day it is," says Dr. Kaylor.
72 hours without sleep: "Pushed to absolute limits"
If you haven't slept for three days, the impact of your exhaustion becomes increasingly dangerous.
At this point, your sleep deprivation has gone beyond what we'd normally describe as 'tired'. "Three days without sleep... fundamentally alters how you experience the world," as Dr. Kaylor explains.
"Your body and mind are pushed to their absolute limits," says Dr. Kaylor. "Your brain is desperately trying to force the rest it needs, whether you’re aware of it or not."
Your desire to sleep becomes "nearly unbearable" — as Dr. Kaylor describes. Hallucinations intensify and you lose the ability to think clearly and communicate effectively.
"This mental chaos can feel disorienting and isolating, leaving you struggling to process what’s happening around you," says Dr. Kaylor.
96 hours+ without sleep: "Caught in a waking nightmare"
If you've made it to four days without sleep (or on minimal sleep), your body is crying out for rest. And Dr. Kaylor's advice is clear: listen to it.
"At this stage, your grip on reality begins to slip in alarming ways. The world around you may feel surreal, as if you’re caught in a waking nightmare," explains Dr. Kaylor.
"Your brain and body are no longer functioning in sync, operating on sheer desperation," she says. "[It's] increasingly difficult to distinguish what’s real from what’s not."
How to cope with a period of sleep deprivation
From tight deadlines to sick children, sleep sometimes has to take a back seat..
No matter why you're sleep deprived, the tips below can help you survive this period with minimal disruption, coming out the other side feeling as fresh as possible.
1. Plan naps
A planned nap (rather than a forced microsleep) can help you catch up on some much needed rest, particularly if you know you won't be getting eight hours that evening.
If you're short on time, confine your nap to 20 minutes (factoring in how long it takes you to fall asleep) and have a glass of water waiting for when you wake up.
However, a longer 90 minute nap allows you to enjoy the benefits of a full sleep cycle. While harder to fit into your day, these longer naps can be more refreshing for long-term sleep deprivation.
2. Keep up with your routine
It's easy to allow a healthy routine to slip when you're sleep deprived. However, if you can maintain a bedtime and wake up time, the regularity can result in better quality sleep (even if you still aren't getting much of it.)
And once awake, a routine can keep your circadian rhythms better in-sync.
Getting sunlight first thing in the morning tells your body it's time to wake up. In the evening, dimming the lights helps your internal clock recognize it's time to wind down.
Keeping a routine also means keeping up healthy habits. Lack of sleep can increase hunger but resist the urge to reach for a midnight chocolate snack — stick to sleep-inducing foods such as pumpkin seeds instead.
3. Sleep more (in moderation)
After a period of sleep deprivation you're probably tempted to catch up on all your sleep in one go.
But as appealing as several days in bed might sound, ultimately, it's going to leave you fatigued and groggy.
It's better to pay off your sleep debt slowly.
Research suggests it can take a while to recover from a period of missed sleep. Adding roughly 15 to 60 minutes to your sleep each night helps you chip away at your debt without risking the disorientating effect of social jet lag.
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