Sleep Deprivation: Can Humans Stay Awake For 6 Days?

Sleep is essential for our physical, cognitive, and mental well-being. While it is unclear exactly how long humans can survive without sleep, the effects of sleep deprivation can start to show in as little as 24 hours. After 36 hours without sleep, the physical impact on the body becomes more apparent, and by 48 hours, most people experience microsleep, a protective reflex where the brain forces a person to fall asleep for a few seconds. After 72 hours without sleep, a person's ability to regulate emotions and accurately perceive the world is severely compromised, and hallucinations are likely. The longest recorded time without sleep is approximately 264 hours, or just over 11 days, achieved by 17-year-old Randy Gardner in 1964.

After 24 hours: the dangers of sleep deprivation

Staying awake for 24 hours can have a significant impact on your body and brain. While it might not cause major health issues, you can expect to feel tired and exhausted. Your risk of errors and accidents in everyday tasks will also increase. According to the CDC, being awake for 24 hours is comparable to having a blood alcohol concentration of 0.10%, which is above the legal driving limit in most states.

• Impaired coordination and memory: You may find it difficult to concentrate and your memory may be affected. You might also experience short-term memory problems and have trouble with coordination.
• Raised levels of stress hormones: Sleep deprivation can lead to increased levels of stress hormones such as cortisol, epinephrine, and norepinephrine. This can interfere with cognitive function and memory.
• Increased blood sugar levels: Sleep deprivation can cause a rise in blood sugar levels, which can have negative health consequences, especially for people with diabetes or prediabetes.
• Higher risk of accidents: The combination of reduced coordination, impaired decision-making, and vision and hearing impairments can lead to a higher risk of accidents.
• "Local sleep" state: Your brain may enter a state called "local sleep" to conserve energy. During this state, some regions of the brain temporarily shut down, resulting in a significant decline in your ability to perform complex tasks.
• Disrupted sleep-wake cycle: Sleep deprivation can disrupt your body's natural sleep-wake cycle, affecting the hormones that regulate important functions.

It is important to prioritize sleep and maintain a consistent sleep schedule to avoid the negative consequences of sleep deprivation. Practicing good sleep hygiene, such as winding down before bed and avoiding stimulants, can help improve your sleep quality and overall health.

After 36 hours: the physical impact on the body

Staying awake for 36 hours can have a significant physical impact on the body. At this stage, you will have an overwhelming urge to sleep. You will likely experience increased appetite and extreme fatigue. You may also start to have microsleeps without realising it. Microsleeps are brief periods of complete unconsciousness that usually last for several seconds. During microsleeps, the brain enters a sleeplike state, and you may feel confused or disoriented when you wake up.

After 36 hours of sleep deprivation, your body's ability to think and make decisions is reduced. You may experience impaired decision-making, inflexible reasoning, and speech impairments, such as poor word choice and intonation.

The sleep-wake cycle helps regulate the release of hormones, including cortisol, insulin, and human growth hormone. Going without sleep for an extended period can alter several bodily functions. For example, sleep deprivation can affect your body's ability to regulate blood sugar levels and increase your risk of developing insulin resistance, which can lead to diabetes mellitus and obesity.

Additionally, sleep deprivation can negatively affect your immune system. The body produces protective substances like antibodies and cytokines during sleep, which help combat foreign invaders such as bacteria and viruses. Without adequate sleep, your body may not effectively fend off these invaders, and it may take longer to recover from illnesses.

After 48 hours: microsleep and the brain

After 48 hours without sleep, the brain will start to enter brief periods of complete unconsciousness, known as microsleep. Microsleep episodes can last from a few seconds to half a minute, during which the brain is in a sleep-like state. They occur involuntarily, and after one of these episodes, a person might feel confused or disoriented.

Microsleep is extremely dangerous when it happens in situations that demand constant alertness, such as driving or operating heavy machinery. People who experience microsleep often remain unaware of it, believing that they were fully awake or had simply lost focus. However, during a microsleep episode, a person's reaction time slows down, and they become less responsive or unresponsive to stimuli.

Microsleep is characterised by a decrease in activity in wakefulness-related regions of the brain and an increase in activity in sleep-related regions. It can be detected through psychological, speech, and behavioural tests, as well as more complex methods like electroencephalography (EEG) and functional magnetic resonance imaging (fMRI).

The transition from wakefulness to sleep during microsleep is regulated by chemicals like adenosine, which causes the 'feeling sleepy' side, and dopamine, which promotes wakefulness and reduces microsleep events.

While microsleep itself is not dangerous, the potential consequences of a lapse in awareness during certain activities can be. If microsleep occurs in an environment free from environmental risks, it is generally not problematic. However, driving a car or operating machinery while microsleeping can lead to accidents and even fatalities.

To prevent microsleep episodes, it is crucial to get sufficient sleep, usually between seven to nine hours for adults. Creating a sleep routine and making lifestyle adjustments, such as reducing caffeine and liquid intake before bed, can also help improve sleep quality.

After 72 hours: the mental health impact

After 72 hours without sleep, a person's mental health will be significantly impacted.

At this stage, a person will experience an overwhelming urge to sleep and will likely be unable to stay awake without assistance. Their ability to think clearly will be severely impaired, especially when it comes to executive functions such as multitasking, remembering details, and paying attention.

Emotionally, a person may become easily irritated, experiencing a depressed mood, anxiety, or paranoia. Research has shown that sleep deprivation at this level makes it more difficult to process others' emotions. A study found that participants who had gone 30 hours without sleep had trouble recognizing angry and happy facial expressions.

Additionally, several days of sleep deprivation can alter a person's perception, leading to hallucinations and illusions. Hallucinations occur when a person sees or hears something that isn't there, while illusions are a misinterpretation of something that is real, such as seeing a sign and thinking it's a person.

The effects of sleep deprivation on mental health are profound and can lead to an increased risk of mental health disorders. While insomnia is often a symptom of psychiatric disorders like anxiety and depression, it is now recognized that sleep problems can also contribute to the onset and worsening of these and other mental health issues.

Chronic sleep deprivation can have particularly severe consequences for children and teenagers, whose brains are still developing. This can lead to poor academic performance, problems getting along with others, a higher risk of engaging in dangerous and antisocial behaviors, and issues with physical growth and development.

Therefore, after 72 hours without sleep, the mental health impact is likely to be severe and far-reaching, affecting a person's ability to function in their daily life.

After 96 hours: the psychosis-like state

After 96 hours without sleep, an individual's perception of reality may be severely distorted, resembling acute psychosis. The urge to sleep will be unbearable, and the individual will experience a rapid and severe decline in mental health. This may involve symptoms of psychosis, where a person becomes detached from reality with complex delusions and violent behaviour.

At this stage, an individual may begin to slur their speech or walk unsteadily. Hallucinations become increasingly frequent and complex. The individual may experience a distorted sense of time, and their perception of reality may be severely altered. They may feel as though they are outside their own body and mind, resulting in a lack of emotion or a careless attitude.

The effects of sleep deprivation at this stage are severe and dangerous. It is important to note that chronic sleep deprivation can have long-term impacts on an individual's health, including an increased risk of cognitive impairment, dementia, poor balance and coordination, weakened immune system, impaired glucose tolerance, Type 2 diabetes, obesity, high blood pressure, cardiac events, stroke, and depression.

It is crucial to seek medical help if you or someone you know is experiencing prolonged sleep deprivation, as the consequences can be life-threatening.

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