Sleep Deprivation: Can Humans Survive 22 Days Without Sleep?

Sleep is essential for our physical, mental, and emotional health. While it is unclear exactly how long humans can survive without sleep, the effects of sleep deprivation start to show within 24 hours. After 36 hours without sleep, the symptoms of sleep deprivation continue to worsen, and by 48 hours, people may experience symptoms of depersonalisation and derealisation. At 72 hours, a person may begin to slur their speech or walk unsteadily, and hallucinations become increasingly frequent and complex.

After 24 hours without sleep, you may experience symptoms such as anxiety, impaired coordination, and memory issues

After 24 hours without sleep, you will likely experience a range of symptoms, including anxiety, impaired coordination, and memory issues.

At this stage of sleep deprivation, you may find it difficult to focus and feel mentally impaired, very tired, and irritable. Your cognitive impairment will be higher than if you were legally intoxicated. You may also experience microsleeps, which are brief periods of involuntary sleep that can last up to 30 seconds. During these microsleeps, your brain is in a sleep-like state, and you may feel confused or disoriented when you "wake up".

The effects of 24 hours of sleep deprivation are similar to those of being under the influence of alcohol, and it is not safe to drive or operate heavy machinery. Your decision-making abilities will be impaired, and you may experience vision and hearing impairments, decreased hand-eye coordination, increased muscle tension, and a higher risk of accidents.

It is important to prioritize sleep and seek medical advice if you are experiencing chronic sleep deprivation or if your sleep patterns have changed suddenly or gradually.

At 36 hours, the effects of sleep deprivation intensify, and you may start to hallucinate

After 36 hours without sleep, the effects of sleep deprivation intensify. You will likely experience increased sleepiness and fatigue, and an overwhelming urge to sleep. You may also start to experience microsleeps, which are brief periods of complete unconsciousness that can last for several seconds.

In addition to physical symptoms, sleep deprivation of this duration can also cause alterations in brain function, such as decreased motivation, inflexible reasoning, and impaired speech. You may also start to hallucinate and experience illusions, which are when you misidentify common objects or sounds. These hallucinations tend to be simple visual hallucinations, such as thinking you see something growing from the floor. However, they can also be auditory, such as hearing voices or dogs barking.

The longer you go without sleep, the more intense these symptoms will become. By 48 hours, you may experience symptoms of depersonalization and derealization, which are problems with accurately perceiving yourself and reality. You may also switch between feelings of apathy and euphoria and have difficulty forming thoughts and sentences.

It is important to note that going without sleep for extended periods can have serious negative effects on your health and well-being. If you are experiencing sleep deprivation, it is recommended to practice good sleep hygiene and, if issues persist, consult a healthcare professional.

After 48 hours without sleep, you may experience symptoms of depersonalisation and derealisation, such as feeling outside your body

Sleep deprivation can have a range of adverse effects on both physical and mental health. After 48 hours without sleep, a person's cognitive performance will have worsened, and they will be very fatigued. At this point, the brain will start to enter brief periods of complete unconsciousness, known as microsleep.

In addition to the emotional, cognitive, physical, and mental health symptoms that come with sleep deprivation, people who go 48 hours or more without sleep may experience symptoms of depersonalisation and derealisation—which are problems with accurately perceiving yourself and reality.

Symptoms of depersonalisation and derealisation include:

• Switching between feelings of apathy and euphoria
• Auditory disturbances, such as not being able to recognise where a sound is coming from
• Feelings of being outside of your body
• Difficulty forming thoughts and sentences

Research has shown that sleep deprivation can cause an increase in dissociative symptoms, such as those associated with depersonalisation and derealisation. One study found that sleep loss increases dissociative symptoms in long-term shift workers and in groups with regularly restricted sleep. Another study found that both the increase in dissociative symptoms following sleep deprivation and the decrease in the ability to consciously suppress thoughts indicate that cognitive function disorders caused by changes in the sleep-wake cycle can be caused through dissociation or deterioration in both areas.

Going without sleep for 72 hours can lead to symptoms resembling acute psychosis, including complex hallucinations and delusions

Sleep is essential for maintaining physical, mental, and emotional health. While the effects of sleep deprivation can vary from person to person, they can be severe and dangerous.

After 72 hours without sleep, people typically experience an overwhelming urge to sleep, and many are unable to stay awake without assistance. This level of sleep deprivation profoundly affects cognitive abilities, especially executive functions such as multitasking, remembering details, and maintaining attention. Emotional regulation is also impacted, with people experiencing heightened irritability, anxiety, paranoia, and depressed moods.

Additionally, perception is significantly altered, leading to complex hallucinations and illusions. These hallucinations can be visual, such as seeing fully formed images, or auditory, like hearing a dog bark. Sleep deprivation can also induce delusions, or false beliefs, such as believing someone has sent you on a secret mission. These symptoms resemble acute psychosis, indicating a loss of touch with reality.

The effects of sleep deprivation at 72 hours are severe and can take several days or even weeks to recover from. It is now considered unethical to conduct research that deprives participants of sleep for more than two days, and chronic sleep deprivation can lead to serious long-term health complications.

Chronic sleep deprivation has been linked to various health issues, including high blood pressure, certain cancers, and an increased risk of accidents

Sleep deprivation can have serious long-term health consequences, including an increased risk of high blood pressure, certain cancers, and accidents.

High blood pressure

Chronic sleep deprivation can lead to high blood pressure (hypertension). Sleep deprivation has long-term damaging effects on your heart and circulatory health. People with chronic sleep deprivation are more likely to develop high blood pressure and high cholesterol.

Certain cancers

Chronic sleep deprivation can increase your risk of developing certain cancers, including colorectal cancer.

Increased risk of accidents

Sleep deprivation can also increase your risk of accidents. Studies have shown that missing a night of sleep can have similar effects on cognitive functioning as having a blood alcohol content of 0.10% – above the legal limit for driving in the US.

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