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It is not clear how long a person can go without sleep, but in a famous 1964 experiment, a person managed to stay awake for 264 hours. Sleep deprivation can negatively affect energy levels, mood, and cognitive functioning. In the long term, it can increase a person’s risk of several chronic conditions.
The Centers for Disease Control and Prevention (CDC) recommend that adults between the ages of 18 and 60 years get at least 7 hours of sleep a night. However, approximately 35 percent of adults in the United States do not get enough sleep. Adults should stay awake no longer than 17 hours to meet the CDC’s sleep recommendation. People tend to experience the adverse effects of sleep deprivation within 24 hours.
In this article, we explore how long a person can go without sleep and look at the effects of sleep deprivation over 72 hours. We also discuss the short- and long-term health effects of sleep deprivation, how much sleep a person needs, and how to improve sleep hygiene.Sleep requirements vary between people and also depend on a person’s age. For example, infants require about twice as much sleep as adults.
However, the amount of time that a person can survive without sleep remains unclear. According to a 2010 review, the current world record for a person going without sleep is 266 hours, which equates to just over 11 days. The most famous sleep deprivation experiment took place in 1964 when a Californian high school student named Randy Gardner managed to stay awake for 264 hours.
Toward the end of the 11 days, Gardner grew paranoid and even started hallucinating. However, he reportedly recovered without any long-term physical or psychological effects. Sleep deprivation occurs when a person gets less sleep than their body needs. The effects of sleep deprivation can vary from person to person. Children and teenagers need more sleep than adults as their brains and bodies are still developing and growing. As such, the effects of sleep deprivation in children can sometimes be more severe or longer-lasting.
General symptoms of sleep deprivation in adults can include:
fatigue and sleepiness during the day
concentration, alertness, and memory difficulties
reduced coordination
irritability
increased appetite
mood changes
Regular or chronic sleep deprivation can also increase a person’s risk of several health conditions, including obesity, diabetes, and heart disease.sleep deprivation can increase the risk of dangerous accidents. According to the National Highway Traffic Safety Administration (NHTSA), in 2015, U.S. police reported 90,000 motor vehicle crashes that involved sleep-deprived drivers. The NHTSA also state that drowsy driving claimed 795 lives in 2017.
An incredibly rare sleep disorder called fatal familial insomnia (FFI) can also result in death. FFI is an inherited condition that results from a mutation in the prion protein (PRNP) gene. The mutated gene produces misfolded prions that accumulate in the thalamus, which is the region of the brain that regulates sleep. The symptoms of FFI typically present in middle adulthood and include:
mild insomnia that gets progressively worse
weight loss
lack of appetite
changes in body temperature
dementia that progresses rapidly
There is currently no cure for FFI, and death usually occurs within 12–18 months of a person first experiencing symptoms.Most people will begin to experience the effects of sleep deprivation after just 24 hours. The CDC claim that staying awake for at least 24 hours is comparable to having a blood alcohol content (BAC) of 0.10 percent. In the U.S., it is illegal to drive with a BAC of 0.08 percent or above.
The effects of going without sleep for 24 hours can include:
drowsiness
irritability
concentration and memory difficulties
reduced coordination
impaired judgment
short-term memory problems
raised levels of stress hormones, such as cortisol and adrenaline
increased blood sugar levels
a higher risk of accidents
muscle tension
Many of these effects occur because the brain attempts to conserve energy by entering a state that doctors refer to as “local sleep.” During local sleep, the body temporarily shuts down neurons in some regions of the brain but not others. People who have entered local sleep may appear fully awake, but their ability to perform complex tasks will significantly decline.
Sleep deprivation also disrupts the body’s natural sleep-wake cycle, which affects hormones that regulate:
growth
appetite
metabolism
stress
the immune system
48 hours without sleep
The effects of sleep deprivation intensify the longer a person stays awake. After going without sleep for 48 hours, a person’s cognitive performance will worsen, and they will become very fatigued. At this point, the brain will start entering brief periods of complete unconsciousness, also known as microsleep. Microsleep occurs involuntarily and can last for several seconds.After 72 hours without sleep, deprivation symptoms and fatigue will intensify even further. Going for 3 days without sleep will have profound effects on a person’s mood and cognition.
In a 2015 study, two astronauts experienced impaired cognitive functioning, increased heart rate, and a reduction in positive emotions after staying awake for 72 hours. Some effects of staying awake for 72 hours include:
extreme fatigue
difficulty multitasking
severe concentration and memory issues
paranoia
depressed mood
difficulty communicating with others
Short-term effects of sleep deprivation
Sleep deprivation can have several adverse effects on health that will resolve once a person gets enough sleep. Short-term effects of sleep deprivation can include:
drowsiness
reduced alertness
decreased concentration
impaired judgment
short-term memory problems
stress
a higher risk of accidents
Chronic sleep deprivation can have lasting effects on a person’s health. These can include an increased risk of:
high blood pressure
obesity
diabetes
heart disease
anxiety or depression
Chronic sleep deprivation can also have significant long-term effects in children, including:
poor academic performance
problems getting along with others
a higher risk of engaging in dangerous and antisocial behaviors
problems with physical growth and development