How Long Can You Go Without Sleep?
Many people today aren’t getting enough sleep, with some getting by on only five to six hours. And worse, many people are proud of how well they can cope with sleep loss, believing they don’t need a full night’s rest. It may leave you wondering how long a human can go without sleep.
While some people can go long stretches without sleep, we feel the effects of sleep deprivation quickly. After skipping one night of sleep, your mind feels sluggish, and your performance drops. You see similar results when you lose a couple of hours of sleep over several nights.
“Sleep serves a vital physiological function and is probably the single most important factor in exercise recovery,” says Dr. Nayantara Santhi. “Everyone is familiar with the recommended duration of sleep. What is less appreciated is that not just how long we sleep, but when we initiate sleep is equally important.”
“Humans are biologically wired to have their main sleep at night. Sleep onset usually occurs after dusk with the onset of darkness. Darkness is important for sleep, which is why our digital lifestyle in the evening has resulted in chronic sleep loss.”
What’s the Record for Going Without Sleep?
When Randy Gardner was 17 years old, he stayed awake for 264 hours as part of a 1965 study on prolonged sleep deprivation. The idea began as his science fair project and a way to beat the then-record of 260 hours of sleep deprivation.
As the experiment progressed, Gardner became nauseated and ate tangerines and oranges to soothe his stomach. He complained of smells he couldn’t stand, and his cognitive abilities declined. Gardner compared it to “early Alzheimer’s.”
Once Gardner broke the world record by staying up for 11 days, he was taken to a naval hospital so researchers could monitor his brain waves as he finally fell asleep. He experienced a high amount of REM sleep that night.
Gardner slept for 14 hours after the experiment; when he woke up, he felt groggy but not abnormally so. His body was quick to fall back into a regular sleep schedule, and his REM sleep levels dropped back to normal as the days passed.
Others have since tried to break Gardner’s record. According to Australia’s National Sleep Research Project, which surveyed the sleep habits of thousands of Australians, the new record might be 18 days, 21 hours, and 40 minutes without sleep. The record holder experienced hallucinations, paranoia, blurry vision, slurred speech, and thinking deficiencies.
If you want to achieve fame by breaking the record for sleep deprivation, we have to tell you it’s not possible. The Guinness Book of World Records no longer accepts entries for going without sleep, out of consideration for potential side effects.
Can I Die From a Lack of Sleep?
We’re not 100 percent certain we would die without sleep. However, if you get too much or too little sleep, your risk of death increases, according to a 2010 review.
Our ability to microsleep might make it difficult for us to die from total sleep deprivation. When we are adjusted to a consistent sleep schedule and then get a poor night’s sleep, we may fall asleep for a moment several times the next day. We can’t control microsleep and may find ourselves dozing off when we don’t want to.
Can Insomnia be Fatal?
Despite the name, fatal familial insomnia (FFI) isn’t as simple as dying from a lack of sleep. It’s an inherited neurodegenerative disease. FFI often develops during middle age, though it’s been observed in those as young as 18.
Sometimes, the first symptom of FFI isn’t insomnia, but progressive dementia. Other symptoms include weight loss, loss of appetite, panic attacks, hypothermia, and hyperthermia.
Why Do We Need Sleep to Survive?
We don’t have a clear answer as to why we need sleep, but scientists have four theories.
One of the earlier theories is that we fall asleep to avoid harm during a time we’re particularly vulnerable. By sleeping, we avoid injuring ourselves in the dark or running into predators.
The counterargument is that conscious vigilance is the best defense against an attack or other emergency. This theory has been largely discredited as a reason why we sleep, Dr. Santhi explains.
Energy Conservation Theory
Living beings all compete for energy resources such as food. By sleeping, we reduce our energy demand and consumption, letting us get by on fewer resources. Many scientists link this theory to the above inactivity theory.
While sleep does cause a drop in energy consumption, theorists have largely moved on to the idea that sleep is for restoration, among other things, Dr. Santhi notes.
It’s a long-standing belief that sleep rejuvenates us, and scientific evidence supports this. Animals deprived of sleep die within a few weeks, and many of our restorative functions, such as the glymphatic system, work best or solely while we’re asleep.
Brain Plasticity Theory
Brain plasticity, also known as neural plasticity or neuroplasticity, is our nervous system’s ability to change in response to outside or internal stimuli. Researchers have linked sleep to brain development and plasticity in infants and children. For adults, researchers note sleep deprivation’s effect on our thinking skills, and that even as we mature sleep continues to influence our brain plasticity.
Similarly, sleep affects how well we learn and remember items of interest, with a good night’s rest improving overall cognition.
How Much Sleep Do I Need?
As we age, the amount of sleep we need decreases. Here’s how much the CDC recommends:
|Age Group||Hours of Sleep Needed|
|Newborn, 0 to 3 months||14 to 17 hours|
|Infant, 4 months to 1 year||12 to 16 hours (naps included)|
|Toddler, 1 to 2 years||11 to 14 hours (naps included)|
|Preschool, 3 to 5 years||10 to 13 hours (naps included)|
|School-Age, 6 to 12 years||9 to 12 hours|
|Teen, 13 to 18 years||8 to 10 hours|
|Adult, 18 to 60 years||7 or more hours|
|Adult, 61 to 64 years||7 to 9 hours|
|Adult, 65 and older||7 to 8 hours|
The amount of sleep you need also depends on your lifestyle. For example, athletes benefit from getting about 10 hours of sleep.
What Happens When I Don’t Get Enough Sleep?
Sleep deprivation affects your performance in multiple ways. When you don’t get enough sleep, you may find it difficult to make decisions or solve problems, or you might find it difficult to control your mood. You’ll likely spend longer on your work tasks than normal, and make more mistakes, too.
Sleep deprivation can make driving to work more challenging. When you’re sleepy, you’re more likely to get into a car accident. Even if you feel fine to drive, the effects of sleep deprivation may prevent you from reacting as you should.
While skipping a night of sleep may have the clearest effects on your performance, losing sleep over time can add up. Even losing as little as 1 to 2 hours of sleep a night over a few days can leave you feeling as if you didn’t sleep at all. Chronic sleep loss is linked to increased risks of developing hypertension, diabetes, obesity, heart disease, stroke, depression, anxiety, and behavioral problems.
Who’s At Risk For Sleep Deprivation?
Acute and chronic sleep deprivation can happen to anyone, but there are lifestyle choices and medical conditions that can increase a person’s chances of sleeping poorly.
If your work or school schedule goes against your natural sleep timing preference, you may find yourself losing sleep. Shift workers, first responders, travelers, and even teens who have to get up early for school all fall into this category.
Similarly, if you only have a few hours in the day to rest, you may find yourself missing out on needed sleep. People who work long hours or more than one job, or even college students with a full course load, a job, and extracurricular activities may not be able to budget enough time for sleep. Work-life balance can be difficult to achieve, but it’s important to do so for better sleep.
Medical conditions and sleep disorders such as chronic pain, sleep apnea, and restless legs syndrome keep people from a full night’s sleep. Many mental and physical conditions are accompanied by a poor night’s sleep, Dr. Santhi notes.
What If I Can’t Sleep?
Recent life events such as job stress or a traumatic event can cause temporary cases of insomnia. This acute insomnia can last a few days or weeks.
If you’re struggling with insomnia, you can fix your sleep schedule by doing the following:
- Establish a set bedtime and waketime. Stick to your routine, even on the weekends.
- Avoid caffeine, which can linger in your system for hours. Don’t just stay away from coffee, but cut back on tea and chocolate as well.
- Try not to eat late dinners, to give yourself time to digest your meal before bed.
- Exercise regularly. Try aerobic exercise for a deeper sleep.
- Turn off your electronics an hour or two before bedtime. The blue light suppresses the evening increase in the hormone melatonin. The evening rise in melatonin is a signal for your brain to prepare or sleep.
- Set up your bedroom for better sleep. Get blackout curtains and an eye mask, clear out distractions such as a TV or computer, and keep your thermostat to between 60 to 75 degrees Fahrenheit.
If your insomnia lasts more than a month, it’s likely a symptom of another sleep disorder, such as sleep apnea. Your doctor or a referred sleep specialist can diagnose the underlying cause.
Frequently Asked Questions
It depends on your situation, but our advice is to avoid all-nighters if you can. If you’re staying up to cram for a test the next day, you would be better off getting a good night’s sleep so you can think clearly. Sleep deprivation affects your memory and how you consolidate information into memory, so you may not recall the needed information. You're better served by sleeping after a little bit of studying than staying up all night.
Two hours of sleep is not great. But when it comes to rest, a little bit is better than none. Even a couple of hours gives your body a chance to recover.
If you’ve ever pulled an all-nighter and felt moody, lethargic, or even sick the next day, you can probably guess that the answer is yes, sleep does matter. There’s a theory that sleep is when our bodies repair and restore themselves. Your chances of developing diabetes, obesity, heart disease, and other conditions can increase if you’re repeatedly losing out on a good night’s rest.
For most people, yes. A two-hour nap can throw off your sleep schedule and cause difficulties with falling asleep at night.
But there are exceptions to every rule. Athletes need a lot more sleep than the average person, and a 2018 study suggests that daytime naps as long as two hours can help them meet their daily sleep requirements.
The older you get, the less sleep you need to feel your best.
- Newborns (0 to 3 months old) need 14 to 17 hours
- Infants (4 to 11 months old) require 12 to 15 hours
- Toddlers ages 1 to 2 need 11 to 14 hours
- Preschoolers ages 3 to 5 require 10 to 13 hours
- Children ages 6 to 13 need 9 to 11 hours
- Teenagers ages 14 to 17 require 8 to 10 hours
- Younger adults ages 18 to 25 need 7 to 9 hours
- Adults ages 26 to 64 years require 7 to 9 hours
- Older adults age 65 and older need 7 to 8 hours
Did We Help?
Humans start feeling the effects of sleep deprivation quickly, whether we lose a whole night’s sleep or just a few hours over several nights. Sleep gives our bodies a chance to repair themselves, and most adults need between 7 to 9 hours of sleep to feel refreshed. If you have trouble sleeping, try improving your sleep hygiene habits, and if problems persist, speak to your doctor.
This article is for informational purposes and should not replace advice from your doctor or other medical professional.