The Hazards Of Sleep Deprivation: A Two-Day Experiment

Sleep is essential for our health and happiness, and going without it can have some surprising and serious effects on the body and mind. But what happens if you don't sleep for two whole days?

After 48 hours, you may experience 'microsleeps'—3-15 second bursts of sleep during which your brain switches off

After 48 hours without sleep, your body will be in a state of extreme sleep deprivation. At this point, your body will start to shut down for microsleeps—brief periods of sleep lasting between 3 and 15 seconds. During these microsleeps, your brain switches off, and you may experience lapses in attention. Your eyes may close, or they may remain open, giving the illusion that you are awake. However, you will be unconscious and unable to respond to external stimuli.

Microsleeps are often preceded by symptoms such as yawning, blinking, and trouble processing information. They can occur even when performing monotonous tasks, such as driving on an empty highway, and can have serious consequences. For example, if you experience a microsleep while driving, you may travel hundreds of feet without realising, putting yourself and others at risk.

The risk of microsleeps increases with sleep deprivation, but they can also happen to well-rested individuals during tedious or repetitive tasks. They are more likely to occur in the afternoon, even if people don't feel particularly sleepy, due to our natural circadian rhythms.

If you find yourself experiencing microsleep episodes, it's important to address your sleep habits and ensure you're getting adequate rest. Short-term fixes, such as taking a break, taking a short nap, or consuming caffeine, can also help reduce microsleeps in the moment.

After 36 hours, you may start hallucinating

After 36 hours of sleep deprivation, you may start to hallucinate. This occurs when you see, hear, or feel things that aren't actually there. Hallucinations are a direct consequence of chronic sleep deprivation.

The visual modality is the most commonly affected sensory function, with 90% of studies reporting visual hallucinations. These hallucinations can include distortions, such as changes in the size, movement, colour, or contours of objects. For example, a stationary object may appear to be moving, or the floor may appear darker. Visual illusions are also common, where common items are transformed into other inanimate objects, animals, or people. For example, mistaking a jacket for a doll. Visual hallucinations can be simple, such as indefinable substances growing from the floor, or complex, such as fully formed images of animals, people, or objects that aren't really there.

Somatosensory hallucinations are the second most common, reported in half of all studies. These include bodily distortions, such as changes in the size of one's body, and tactile hallucinations, such as the sensation of being touched. Auditory hallucinations are less common, reported in a third of studies, and include mislocalisation of sounds and changes in the quality of voices.

In addition to hallucinations, other symptoms of sleep deprivation after 36 hours include increased appetite, extreme fatigue, and an overwhelming urge to sleep. Cognitive functions continue to be impaired, with reduced concentration and creativity, and an increased inability to properly perceive the length of time.

After 24 hours, your body will produce more stress hormones and cease glucose metabolism

Sleep deprivation can cause the body to produce more stress hormones and cease glucose metabolism. After 24 hours without sleep, the body's stress response system, the hypothalamic-pituitary-adrenal (HPA) axis, becomes hyperactive. This leads to an increase in the production of stress hormones such as cortisol, which can have a negative impact on glucose metabolism.

The HPA axis plays a crucial role in regulating the body's response to stress. When the body is under stress, the HPA axis is activated, leading to the release of cortisol and other stress hormones. Cortisol has a wide range of effects on the body, including increasing blood sugar levels and impairing insulin sensitivity. This can lead to a state of insulin resistance, where the body's cells become less responsive to insulin, making it harder to regulate blood sugar levels.

In addition to the HPA axis, sleep deprivation can also affect other systems involved in glucose metabolism, such as the sympathetic nervous system and the endocrine system. Sleep deprivation can increase sympathetic nervous system activity, leading to the release of catecholamines, which can impact glucose metabolism. It can also disrupt the normal release of hormones that regulate glucose metabolism, such as insulin and glucagon.

Furthermore, sleep deprivation can lead to increased inflammation and oxidative stress, which can contribute to insulin resistance and impaired glucose metabolism. Sleep deprivation has also been linked to changes in appetite and food intake, which can further impact glucose metabolism. Overall, sleep deprivation can have a significant impact on the body's ability to regulate blood sugar levels and can contribute to the development of metabolic disorders such as obesity and type 2 diabetes.

After 72 hours, your perception of reality may be severely distorted, resembling acute psychosis

After 72 hours of sleep deprivation, your perception of reality may be severely distorted, resembling acute psychosis. This means that you may experience a loss of touch with reality.

After three days without sleep, you will likely experience an overwhelming urge to sleep, and you may be unable to stay awake without assistance. Your ability to think will be severely limited, especially when it comes to executive functions such as multitasking, remembering details, and paying attention.

Emotionally, you may experience irritability, a depressed mood, anxiety, or paranoia. Research has found that sleep deprivation at this stage can make it more difficult to process others' emotions. For example, in one study, participants with 30 hours of sleep deprivation had difficulty recognising angry and happy facial expressions.

Your perception will also be significantly altered. You may experience complex visual hallucinations (seeing fully formed images), auditory hallucinations (thinking you hear a dog barking, for instance), and delusions (false beliefs). For example, you may develop the delusion that someone has sent you on a secret mission, or that someone is plotting against you.

In addition, you may experience perceptual distortions, such as visual distortions (where objects appear a different size or shape than they are), illusions (misidentifying common objects or sounds), and depersonalisation and derealisation (problems with accurately perceiving yourself and reality).

Sleep deprivation can lead to a weakened immune system, making you more susceptible to illnesses

24 Hours Without Sleep

After 24 hours of no sleep, you will experience impaired coordination, memory, and judgment. This is because the body increases the production of stress hormones like cortisol and adrenaline to compensate for the fatigue. The cognitive impairment at this stage is comparable to having a blood alcohol content of 0.1%, which is over the legal limit for driving in most states. You will also have a reduced reaction time, slurred speech, and slowed thinking.

36 Hours Without Sleep

After 36 hours without sleep, your physical health starts to be negatively impacted. High levels of inflammatory markers are in the bloodstream, which can lead to cardiovascular disease and high blood pressure. Your hormones are also affected, leading to increased feelings of anxiety and mood swings. You will likely feel sluggish and experience delayed reaction time, foggy memory, and an inability to concentrate, learn new information, and process social cues.

48 Hours Without Sleep

At the 48-hour mark, the body begins to compensate by shutting down for "microsleeps", which are 3- to 15-second bursts of rest. Your brain switches off during these microsleeps, and your eyes may remain open. You will experience increased irritability, anxiety, foggy memory, and impaired thinking. Some people may even encounter hallucinations, seeing or hearing things that aren't there. Research has also shown a decrease in NK cells, which play a key role in fighting off viruses and tumor formation.

72 Hours Without Sleep

After 72 hours without sleep, your perception of reality may be severely distorted, resembling acute psychosis. Your urge for sleep will also feel unbearable, and microsleeps will increase in length and frequency. Complex hallucinations may occur, and you may experience delusions and paranoia.

96 Hours Without Sleep and Beyond

After 96 hours without sleep, the symptoms will continue to worsen. It can take days or even weeks to recover from sleep deprivation, and the longer you've been awake, the longer it will take to get back on track.

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