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Understanding Sleep Deprivation and How Long Your Body Can Go Without Sleep

Updated September 9, 2019

Sacrificing sleep can seem like a requirement of our modern lifestyles: Between our highly programmed personal lives and professional obligations, running on empty is often our only option. 

But how long can you go without sleep without encountering serious medical and safety consequences?

Furthermore, what degree of sleeplessness can the human body sustain? How long could you go without sleep if you absolutely had to? In this article, we’ll provide answers to these critical questions, and help you assess the risks of sleep deprivation for yourself.

Sleep Deprivation: Living on Too Little Sleep

Generally speaking, sleep deprivation occurs when individuals fail to get enough sleep to function fully and maintain their physical and emotional well-being. This concept differs slightly from “sleep deficiency,” a broader term that covers many issues related to sleep quality.

Unfortunately, large-scale studies indicate that sleep deprivation is exceedingly common among Americans. According to one recent analysis of nearly 400,000 individuals’ sleep patterns, approximately a third of U.S. adults get six hours of sleep or less each night,  which is less than how long can you go without sleep. While people’s sleep needs vary significantly, the Centers for Disease Control and Prevention (CDC) recommend that adults get at least seven hours of sleep per night. 

man resting pillow on back of his head

Over time, that gap can accumulate into massive sleep debt, leaving many of us perpetually fatigued. Moreover, Americans are moving in the wrong direction, sleeping significantly less than they have in decades past.

Are you among the many experiencing sleep deprivation to some degree? Here are some signs to look out for in your own life. If the following list includes many of your own experiences and behaviors, it may be time to address your sleep debt.

Signs of Sleep Deprivation

  • Yawning: The classic sign of sleepiness can signal an underlying issue.
  • Moodiness and irritability: Skimping on sleep can compromise our emotional stability. If you’re quick to frustration or consistently feeling depressed, a lack of rest could be the culprit. Too many sleepless nights can also lead to anxiety, according to recent research.
  • Forgetfulness: If minor details seem to be skipping your mind more than usual, sleep debt could be to blame.
  • Trouble concentrating and learning new material: Sleep deprivation can detract from your capacity to focus, which makes retaining new information more difficult. This symptom can be particularly apparent at work, where your productivity may suffer.
  • Carbohydrate cravings: Research indicates that sleep-deprived people are typically hungrier and more inclined to choose unhealthy snacks. This phenomenon may explain why sleep deprivation is also linked to weight gain.
  • Clumsiness: Going without sleep can hurt our coordination, resulting in trips, slips, and spills we might not otherwise experience.
  • Low sex drive: Sleepy individuals may simply be less inclined toward romantic activity, feeling too tired to get frisky. But scientists also say that sleep deprivation can have hormonal ramifications, causing a loss of interest in sexual activity. 
  • Breakouts: Sleep deprivation compromises your immune system, giving bacteria new freedom throughout the body. One unfortunate reflection of this phenomenon is acne: Pimples are a sign that bacteria are present on your skin. 

Sleep Deprivation Dangers

Beyond the unpleasant symptoms discussed above, sleep deprivation can have long-term health consequences – including an elevated risk of life-threatening illnesses. Additionally, chronic fatigue leaves us vulnerable to dangerous accidents, especially on the road. 

On any given day, skimping on sleep can seem like a minor decision without major implications for your quality of life. But to truly understand the nature of sleep deprivation and make informed choices, you’ll need to understand the threats associated with resisting rest. 

Chronic Health Risks of Sleep Deprivation

  • Heart disease: Studies show that an ongoing lack of sleep can devastate cardiovascular health. One recent analysis found that short sleepers were far more likely to have problematic thickening in the walls of their arteries, which can lead to a range of heart problems. Furthermore, previous research indicates connections between sleeplessness and high blood pressure, obesity and other heart disease risk factors. 
  • Cancer: Short or irregular sleep schedules have been linked to increased incidence of several forms of cancer. According to experts, colon and breast cancers are particularly tied to sleep deprivation.
  • Alzheimer’s disease: Sleeplessness can cause increased production of beta-amyloid, a brain protein associated with Alzheimer’s disease. Accumulation of beta-amyloid can also cause sleep disruptions, potentially initiating a vicious cycle. 
  • Diabetes: Some studies show that even occasional sleep loss can increase one’s risk of being diagnosed with diabetes. These findings could relate to the impacts of sleep deprivation upon our eating habits: If we eat unhealthily when fatigued, our diabetes risk increases as well.
  • Mental health disorders: A lack of sleep can exacerbate or precipitate many mental health challenges, including depression, anxiety, and a range of severe psychiatric disorders. If you’re managing the symptoms of these mental health disorders in your own life, sleep is an essential component of your continued well-being. 

Accident Hazards of Sleep Deprivation

  • Automobile accidents: Public safety researchers have found that even minor sleep deprivation elevates one’s odds of being involved in a car crash. For drivers with a more severe lack of sleep, the statistics are especially scary. Individuals with four hours of sleep or less, for instance, were 15 times more likely to be responsible for a car crash than well-rested people. In fact, sleepiness is a factor in nearly 10% of crashes nationwide, according to an analysis conducted in 2018.
  • Workplace accidents: Fatigue is a major peril on job sites involving dangerous activities or heavy machinery. By some estimates, sleep-deprived workers are 70% more likely to be involved in workplace accidents than their well-rested peers.

How Long Can You Go Without Sleep?

Given the information we’ve shared thus far, you may be reconsidering whether to sacrifice your sleep for any reason. But if you needed to stay up for hours on end, how long could you make it? What would happen to your body as time went on?

The answers to these questions will depend on several personal factors, such as your age and typical sleep needs. But much of what we do know about extreme sleep deprivation comes from a surprising source: a 17-year-old boy.

Randy Gardner’s Record

In 1963, San Diego high schooler Randy Gardner set a record for sleeplessness that still stands today: 11 days and 25 minutes. He did so with the help of two friends and Stanford professor William Dement. Intriguingly, Gardner relied on physical activity to sustain his experiment, bowling or playing basketball to stay awake.

man drinking coffee and snacking on pastry

In the intervening years, however, others have called Gardner’s record into question: Some reports say he dozed off intermittently. Additionally, no one can challenge his official record; Guinness World Records has stopped accepting new entries in this category, fearful that challengers would incur serious health consequences.

Garnder’s example does suggest that individuals can stay up for multiple days if necessary. But what happens to the body when we do so?

Symptoms of Prolonged Sleep Deprivation

According to sleep scientists, serious symptoms of sleep deprivation can set in after 48 hours of wakefulness. At this stage, many individuals experience “microsleeps,” or brief, involuntary periods in a state resembling regular sleep. 

If you’ve ever nodded off by accident and then jolted back away, you know what these microsleeps feel like. Returning to wakefulness can be disorienting, and you won’t benefit much from this superficial slumber. They typically last up to 15 seconds, too short a time to attain deeper stages of restorative rest. 

If you push your sleepless streak even further, your symptoms may grow even more bizarre. Researchers have consistently observed auditory hallucinations, perceptual distortions and other forms of psychosis among individuals who go more than 72 hours without sleep. 

Is it possible to go so long without sleep that you actually die? There are no modern records of such cases, but many deaths have been linked to sleep deprivation indirectly. More importantly, the chronic illnesses and accidents we mentioned above cause millions of deaths worldwide each year. In this sense, sleep deprivation is often a deadly factor, if not the singular reason for any given death.

Staying Up Safely: Surviving Unavoidable All-Nighters

While we’d never advise foregoing the rest you need, there are occasions on which sleepless nights are inevitable. Take the classic college all-nighter: Your final exam is tomorrow and you’ve hardly studied at all. Or maybe you’re orchestrating a massive event and there’s no time to rest until the festivities are over. 

Sure, maybe you could have planned better in advance. But now that it’s crunch time, you have no choice. If you absolutely have to stay awake, what’s the safest, smartest way to do so? More importantly, what can you do to make sure you successfully stay awake?

All-Nighter Advice

  • Stock up on sleep: If you know you’re in for a long night, take whatever rest you can get beforehand. Even a brief nap may prove helpful in the long run. Ideally, you can get two or three hours of sleep under your belt before your all-nighter begins. 
  • Hydrate and caffeinate carefully: While caffeine might seem like the best fuel for a sleepless night, it can cause problems in high doses. Drink too much and you could confront the symptoms of an overdose, such as a splitting headache, shaky hands, or a mounting sense of anxiety. To be safe, alternate your coffee or energy drinks with water. To make it through the night, you’ll need to be properly hydrated. 
  • Snack strategically: As the night drags on, you may find yourself drawn to convenient treats, such as chips, cookies, and candy. And while you may deserve a reward for all your hard work, these snacks will set you up for a catastrophic crash once the carbs set in and the sugar wears off. For a better shot at sustained energy, opt for high-protein alternatives like nuts or nutritious fruits and veggies. 
  • Recover right: The day after an all-nighter can feel terrible or triumphant, depending upon the outcome of whatever you stayed up for. Regardless, be smart about bouncing back. If you can, take a quick nap to make it through the rest of the day. Nap the whole day away, however, and you may throw your sleep cycle out of whack.

Skimping on Sleep: Short-Term Gain, Long-Term Pain?

We hope this article helps you make better choices about the sleep you need – and the potential consequences of depriving yourself. Ultimately, life’s demands sometimes force us to make do with too little rest, so we’re all sleep-deprived on occasion.

Still, if we consistently sacrifice our sleep to pursue our goals, we neglect a larger priority: our well-being. Understanding sleep deprivation means grappling with these trade-offs and protecting our health accordingly by getting sufficient sleep.