How Long Can A Person Go Without Sleeping?

How Long Can a Person Go Without Sleeping?

The precise answer to how long a person can go without sleeping is roughly 11 days or about 264 hours. This duration was recorded during an experiment conducted by Randy Gardner in 1964. However, it’s important to note that going without sleep for such an extended period is extremely detrimental to one’s health. While this timeframe provides a fundamental understanding, the effects of sleep deprivation can begin much sooner.

The Importance of Sleep

Sleep is a fundamental biological necessity crucial for overall health and well-being. It is as essential as food, water, and air. During sleep, the body undergoes various restorative processes, including memory consolidation, tissue repair, and the release of growth hormones. Lack of sleep impairs these critical functions and has wide-ranging impacts on physical and mental health.

The Stages of Sleep Deprivation

Sleep deprivation can be divided into different stages, each with progressively more severe effects on the body and mind:

24 Hours Without Sleep

Missing a full 24 hours of sleep can make you feel irritable, tired, and sluggish. You might experience mood swings, reduced coordination, and an inability to concentrate. Physically, you might experience tremors, itchy eyes, and increased levels of stress hormones like cortisol.

36 Hours Without Sleep

After 36 hours of no sleep, the physical and mental impairments become more noticeable. Your cognitive functions deteriorate, resulting in memory lapses and impaired decision-making abilities. Your speech may become slow and slurred. You might also experience an increased risk of cardiovascular problems as your heart rate and blood pressure rise.

48 Hours Without Sleep

At the 48-hour mark, microsleeps begin to occur. Microsleeps are brief episodes of sleep that last only a few seconds. You may not even realize they are happening, but these can pose serious dangers, especially if you are driving or operating machinery. Your immune function will be notably compromised, making you more susceptible to infections. You might experience paranoia, hallucinations, and extreme mood swings.

72 Hours or More Without Sleep

After 72 hours of being awake, severe cognitive deficits and profound physical effects are evident. Hallucinations become more frequent and intense. Your sense of reality becomes highly distorted, and you may experience delusions. Your ability to think, reason, and even perform basic tasks will be significantly impaired. At this stage, the risks of accidents and injuries are extremely high.

Psychological Effects of Sleep Deprivation

Sleep deprivation has profound psychological effects:

Mood Disorders

Lack of sleep is closely associated with mood disorders. Insufficient sleep can lead to heightened levels of stress, anxiety, and irritability. Prolonged sleep deprivation can even contribute to the development of depression and other mood disorders.

Cognitive Impairments

Your cognitive abilities, including memory, attention, and decision-making skills, are severely impacted by lack of sleep. You may find it challenging to focus, solve problems, or recall information efficiently. Academic and professional performance can be significantly affected.

Hallucinations and Paranoia

As aforementioned, extended periods without sleep can lead to hallucinations and paranoia. This condition becomes particularly severe after 72 hours of sleep deprivation, where you might start seeing or hearing things that aren’t there.

Physical Effects of Sleep Deprivation

The physical detriments of not sleeping are extensive and can affect virtually every system in your body:

Compromised Immune System

Your immune system relies on sleep to function effectively. Lack of sleep impairs the body’s ability to fight off infections and illnesses. You become more prone to common colds, flu, and other pathogens.

Increased Risk of Chronic Diseases

Extended periods of sleep deprivation have been linked to an increased risk of chronic diseases such as heart disease, diabetes, obesity, and hypertension. The stress hormones released during periods of wakefulness can wreak havoc on your cardiovascular system and metabolism.

Weight Gain

Sleep deprivation affects hormones that regulate hunger and appetite, such as ghrelin and leptin. With increased levels of ghrelin (which stimulates appetite) and decreased levels of leptin (which suppresses appetite), you are likely to experience significant weight gain over time.

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Accident Risk

Whether it’s falling asleep behind the wheel or making critical errors at work, the dangers associated with sleep deprivation cannot be overstated. This increased risk of accidents can result in severe injuries or even fatalities.

Why Do We Need Sleep?

Understanding why we need sleep sheds light on the severe ramifications of going without it:

Memory and Learning

Sleep plays a critical role in consolidating new information and experiences into long-term memory. It also aids in learning by promoting the processes that underpin the acquisition of new skills and knowledge. Without adequate rest, these cognitive functions are severely hindered.

Emotional Regulation

Sleep helps stabilize mood and emotions. It allows the brain to process and react to emotional experiences effectively. Lack of sleep makes it harder to manage stress and cope with emotional difficulties, thereby affecting personal and professional relationships.

Physical Restoration

During sleep, the body goes through various stages of repair and growth. Tissues are repaired, and muscles are built. Growth hormones are released, and energy reserves are replenished. Without these restorative processes, the body becomes progressively weakened.

Toxin Removal

Sleep facilitates the removal of toxins that accumulate in the brain throughout the day. The glymphatic system, which is more active during sleep, ensures that these toxins are flushed out, keeping the brain healthy and functional.

The Longest Recorded Period Without Sleep

Randy Gardner holds the record for the longest documented period without sleep. In 1964, as part of a science project, he stayed awake for 11 days and 24 minutes. During this experiment, Gardner experienced a range of cognitive and behavioral effects, including mood swings, memory lapses, hallucinations, and severe impairments in motor skills. While Gardner’s record gives us a benchmark, it is not advisable to attempt such prolonged sleep deprivation due to the associated dangers.

How the Body Tries to Cope

When deprived of sleep, the body attempts to compensate in several ways:


As mentioned earlier, microsleeps are brief moments of sleep that last only a few seconds. They occur involuntarily and are the body’s way of trying to get some rest. Microsleeps can happen without the individual being aware, leading to dangerous situations, particularly if the person is driving or operating heavy machinery.

Altered Hormone Production

The body’s production of hormones such as cortisol, growth hormone, and leptin is significantly altered by sleep deprivation. Increased cortisol levels contribute to stress, while irregular growth hormone and leptin production can affect metabolism, appetite, and overall physical health.

Heightened Stress Response

Sleep deprivation triggers the body’s stress response, leading to elevated levels of stress hormones like cortisol and adrenaline. This can create a cycle where stress impairs sleep, which then increases stress levels even further.

Treatment and Prevention of Sleep Deprivation

Addressing sleep deprivation involves a combination of lifestyle changes, medical treatments, and creating a sleep-conducive environment:

Sleep Hygiene

Good sleep hygiene includes practices such as maintaining a regular sleep schedule, creating a dark and cool sleeping environment, and avoiding caffeine and electronic devices before bedtime. These habits can significantly improve the quality and quantity of sleep.

Medical Interventions

In some cases, underlying medical conditions such as sleep apnea, insomnia, or restless leg syndrome may contribute to sleep deprivation. Consulting a healthcare provider can help identify and treat these conditions, potentially involving medications, therapy, or the use of CPAP machines for sleep apnea.

Cognitive Behavioral Therapy (CBT)

CBT for insomnia (CBT-I) is a form of therapy that helps individuals address the thoughts and behaviors that contribute to sleep problems. It’s highly effective in treating chronic insomnia and improving sleep patterns.

Stress Management

Managing stress through techniques such as mindfulness, meditation, and exercise can significantly improve sleep quality. These activities help calm the mind and prepare the body for restful sleep.

Long-Term Consequences of Chronic Sleep Deprivation

Chronic sleep deprivation can have severe long-term consequences on health:

Mental Health Issues

Prolonged lack of sleep is linked to chronic mental health problems such as anxiety, depression, and bipolar disorder. The relationship between sleep and mental health is cyclical, with poor sleep exacerbating symptoms and mental health issues leading to further sleep problems.

Cardiovascular Problems

Persistently poor sleep increases the risk of cardiovascular issues, including hypertension, heart disease, and stroke. The stress caused by lack of sleep on the heart and blood vessels can lead to long-term health deterioration.

Impaired Immune Function

Chronic sleep deprivation weakens the immune system over time, making the body more susceptible to infections and illnesses. This can result in more frequent and severe health issues.

Cognitive Decline

Ongoing sleep deprivation contributes to long-term cognitive decline, affecting memory


  • Leo Murray

    Hey, I'm Leo Murray, your friendly guide to the galaxy of great sleep at GoodlSleepHub. As a certified Sleep Therapist with a lively spirit for all things restful, I'm here to take the mystery out of your zzz's. My mission is to make good sleep accessible to everyone, mixing solid science with a dash of humor. When not demystifying sleep cycles or hunting down the best mattresses, I'm an avid mountain biker and a coffee connoisseur. My weekends often involve exploring new trails or experimenting with coffee blends. These adventures fuel my philosophy: great days are born from great nights. So, come along as we journey through the night skies of sleep. I promise to keep it informative, light-hearted, and always focused on getting you the restful sleep you deserve. Remember, in Leo's world, every night is an opportunity for a perfect dream!

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