The Ultimate Sleep Deprivation Experiment: 22 Days Without Sleep

Sleep is essential for human functioning. While the exact survival limit is unknown, the longest anyone has ever gone without sleep is 264 hours, or 11 days. After just 24 hours without sleep, the negative effects are already evident, with similar cognitive effects to a blood alcohol concentration of 0.10%. After 36 hours, hallucinations may begin, and after 48 hours, symptoms of psychosis can emerge. Going without sleep for 22 days would likely have severe consequences on both the body and mind, and it is highly unlikely that anyone could survive this long without sleep.

After 24 hours, you will experience impaired decision-making, vision and hearing impairments, and increased risk of accidents

After 24 hours without sleep, you will experience impaired decision-making. Research shows that staying awake for a day causes similar cognitive effects as having a blood alcohol concentration of 0.10%, which is higher than the legal limit for driving. This means that your ability to make decisions and judgements will be impaired.

You will also experience vision and hearing impairments. Your ability to accurately perceive an object's shape and size will be affected, and your depth perception will be impaired. Your hearing may also be affected, though there is limited information on this.

Finally, your risk of accidents will increase. This is due to the various impairments mentioned above, as well as an increase in stress hormones like cortisol and adrenaline, which is your body's attempt to compensate for fatigue.

After 36 hours, you will experience decreased motivation, inflexible reasoning, and speech impairments

After 36 Hours Without Sleep, You Will Experience Decreased Motivation, Inflexible Reasoning, and Speech Impairments

Staying awake for 36 hours will cause a range of symptoms, including decreased motivation, inflexible reasoning, and potential speech impairments.

Decreased Motivation

Sleep deprivation has been shown to decrease motivation to engage in physical and social activities. In one study, participants who were sleep-deprived expressed less interest in activities such as walking, exercising, and socialising with friends, and a greater desire to be alone. This decrease in motivation may be due to the competing drive to sleep, as sleep-deprived participants also showed a greater willingness to utilise resources (e.g. paying money) to be allowed to sleep.

Inflexible Reasoning

Sleep deprivation can also lead to alterations in brain function and cognitive flexibility. One study found that participants who had been awake for 36 hours experienced reduced concentration and a reduced ability to think creatively. Another study found that sleep deprivation was associated with reduced cognitive flexibility, particularly in individuals with schizophrenia and major depressive disorder.

Speech Impairments

Sleep loss can affect the characteristics of speech, including speaking more slowly and with less energy. However, these effects are typically small and may not have a significant impact on person-to-person communication. One study found that sleep-deprived individuals showed no difference in speaking duration, volume, or consistency during a collaborative task.

Overall, staying awake for 36 hours can have significant impacts on motivation, reasoning, and speech. These symptoms are likely due to the competing drive to sleep and alterations in brain function caused by sleep deprivation.

After 48 hours, you will experience periods of microsleep, impaired immune system, and increased risk of hallucinations

After 48 hours without sleep, you will likely experience microsleep, an impaired immune system, and an increased risk of hallucinations.

Microsleep refers to brief periods of light sleep that can last up to 30 seconds. These episodes occur involuntarily, and you may feel confused or disoriented when you snap out of them. At this stage, your brain will start entering brief periods of complete unconsciousness.

Your immune system will also take a hit, with inflammatory markers circulating at increased levels. Research has shown that natural killer (NK) cell activity, which is responsible for responding to immediate health threats like viruses or bacteria, decreases with sleep deprivation.

Additionally, you may start to have blurry or double vision, which can progress into more severe distortions of reality and hallucinations. These hallucinations become more likely and harder to distinguish from reality the longer you go without sleep.

After 72 hours, you will experience a profound limitation in your ability to think, severe emotional changes, and complex hallucinations

After 72 hours without sleep, you will experience a profound limitation in your ability to think. This level of sleep deprivation can make it difficult to see even simple tasks through to completion. Executive functions such as multitasking, remembering details, and paying attention will be impaired.

Emotions are also affected by sleep deprivation. People who have gone without sleep for this long may be easily irritated, and may experience a depressed mood, anxiety, or paranoia. Research has also found that sleep-deprived individuals have difficulty processing others' emotions. In one study, participants with 30 hours of sleep deprivation had trouble recognizing angry and happy facial expressions.

Finally, several days of sleep deprivation can significantly alter perception. You might experience complex hallucinations, which occur when you see something that isn't there. Illusions are also common, which is when you misinterpret something that is real. For example, you might see a sign and think it's a person.

After 96 hours, your perception of reality will be severely distorted, resembling acute psychosis

After 96 hours without sleep, your perception of reality will be severely distorted, resembling acute psychosis. This means that you will experience a rapid and severe decline in mental health, with symptoms such as complex hallucinations and violent behaviour. Your urge to sleep will also become unbearable.

The longer you go without sleep, the more severe the symptoms of sleep deprivation become. After 72 hours without sleep, you may begin to slur your speech or walk unsteadily, and your hallucinations will become more frequent and complex. Your emotions will also be affected, with people experiencing a depressed mood, anxiety, or paranoia. Research has also shown that sleep-deprived individuals have difficulty processing others' emotions, such as recognising angry and happy facial expressions.

After 48 hours without sleep, you will likely experience blurry or double vision, which may progress into distortions of reality and hallucinations. You may also have trouble perceiving time and experience depersonalisation, feeling like you are outside your body and mind. As a result, you may seem unemotional or careless.

At the 36-hour mark, you will have an overwhelming urge to sleep and may experience microsleep, which is a brief period of light sleep that can last up to 30 seconds. Your body will involuntarily enter these microsleep episodes, after which you may feel confused or disoriented. Your ability to regulate stress and emotions will also be affected.

Even after 24 hours without sleep, the signs of sleep deprivation become evident. You may feel more anxious or agitated, and your performance on tasks will continue to decline, making you more prone to errors and misinterpretation of social cues. Your visual perception may also be altered, with trouble perceiving depth, shapes, and sizes of objects.

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