Sleep Deprivation: Counting Days Without Rest

Sleep deprivation can occur after just 24 hours of no sleep, but the longer a person goes without sleep, the more severe the symptoms become. After 36 hours, people tend to experience an overwhelming urge to sleep, increased appetite, and extreme fatigue. At 48 hours, symptoms worsen, and it becomes even harder to stay awake. After 72 hours, or three days, of sleep loss, the urge to sleep will strengthen and may become uncontrollable, and hallucinations may become more complex. Once a person has been awake for 96 hours or more, their perception of reality may be severely distorted, resembling acute psychosis.

After 24 hours: impaired decision-making, impaired vision and hearing, decreased hand-eye coordination

After 24 hours of sleep deprivation, you can expect to feel tired, exhausted, or "off". Your risk of errors and accidents in everyday tasks increases, as your decision-making, vision, and hearing are impaired, and your hand-eye coordination decreases.

Impaired decision-making

After 24 hours of sleep deprivation, your risk of errors and accidents in everyday tasks increases. This is because your ability to make decisions is impaired.

Impaired vision and hearing

After 24 hours of sleep deprivation, your vision and hearing are impaired. Research has shown that sleep deprivation can cause a "tunnel-vision" effect, in which attention is restricted to the centre of the visual field. This means that your peripheral vision is neglected.

Decreased hand-eye coordination

After 24 hours of sleep deprivation, your hand-eye coordination decreases. Peak velocity of saccades is reduced, and gaze-target synchronisation of visual tracking is deteriorated.

After 36 hours: decreased motivation, inflexible reasoning, speech impairments

After 36 hours of sleep deprivation, you will likely experience an overwhelming urge to sleep. This is in addition to the effects of 24 hours of sleep deprivation, which include an increased risk of errors and accidents in everyday tasks. You may also experience microsleep, which is when you fall asleep for a few seconds without realising it.

At this stage, you may also start to experience decreased motivation. This could present as a lack of interest in activities you once enjoyed, or a general feeling of fatigue and exhaustion. It might become difficult to initiate tasks or find the energy to complete them.

Sleep deprivation can also cause cognitive impairments, including inflexible reasoning. This means that your thinking may become more rigid and less adaptable. You might find it challenging to consider alternative solutions to problems or to think creatively. Your problem-solving abilities may be hindered, and you may have trouble with complex tasks that require flexible thinking.

In addition, your speech may be impaired. You may find it difficult to articulate your thoughts clearly, or you might experience difficulties with fluency or word-finding. Your speech may become slower or less coordinated. These impairments can impact your ability to communicate effectively and may be frustrating or embarrassing.

It is important to note that the effects of sleep deprivation can vary between individuals, and some people may experience more severe symptoms than others. However, it is clear that going without sleep for 36 hours can have significant impacts on motivation, reasoning, and speech.

After 48 hours: microsleeps, disrupted immune system, increased inflammatory markers

After 48 hours of sleep deprivation, the body enters a state of extreme sleep deprivation. At this point, it becomes increasingly challenging to stay awake, and one is more likely to experience microsleeps—brief periods of sleep lasting seconds rather than minutes or hours. During microsleeps, a person may nod off or keep their eyes open, but their brain is not processing external information as it usually would. This can lead to a heightened risk of accidents, especially while driving or operating heavy machinery.

Sleep loss also has a significant impact on the immune system. Scientific evidence suggests that sleep has a powerful effect on immune functioning, and sleep loss can affect various parts of the immune system, leading to the development of a wide range of disorders. For example, restricting sleep can reduce natural killer (NK) cell activity, which plays a crucial role in fighting tumor cells. Additionally, sleep loss can lead to the generation of inflammatory cytokines, protein molecules that promote inflammation and are linked to cardiovascular and metabolic disorders.

The disruption of the immune system after 48 hours of sleep deprivation can also increase the risk of infection. Studies have shown that restricting sleep followed by a period of recovery sleep resulted in a significant decrease in the production of antibodies to the influenza vaccination compared to those who maintained regular sleep hours. This indicates that sleep loss can impair immune functioning, making individuals more susceptible to infections and various disorders.

After 72 hours: overwhelming urge to sleep, impaired thinking, altered emotions

After 72 hours of sleep deprivation, the urge to sleep will be incredibly strong and possibly uncontrollable. The body will experience more frequent and longer microsleeps, which are brief periods of complete unconsciousness that can last for several seconds.

At this stage, sleep deprivation will significantly impair perception, and complex hallucinations may occur. An individual may struggle to interpret what they are seeing, and it may be difficult to read other people's emotions.

Cognitive functioning will be impaired, and individuals may experience severe concentration and memory issues, as well as difficulty communicating with others. Emotional regulation will also be affected, with people reporting feelings of irritability, anxiety, and depression.

The effects of sleep deprivation are cumulative, and the longer a person goes without sleep, the more severe the symptoms become. By 72 hours, the body and mind are significantly impacted, and the urge to sleep is overwhelming.

After 96 hours: unbearable urge to sleep, distorted perception of reality, state of psychosis

After 96 hours of sleep deprivation, an individual will experience an unbearable urge to sleep, a distorted perception of reality, and a state of psychosis. This is the fifth and final stage of sleep deprivation, with the previous stages building up to this point.

At this stage, an individual will experience a severe distortion of reality, with their perception of reality being comparable to acute psychosis. This is a state of mental illness characterised by a disconnection from reality, often involving hallucinations and delusions. The individual will also experience an unbearable desire to sleep, with their urge to sleep becoming overwhelming and uncontrollable.

Prior to this, at stage four (72 hours without sleep), an individual will experience overwhelming sleepiness, delusions, and complex hallucinations. They will also experience disordered thinking and depersonalisation, which involves feeling outside of oneself.

The fourth stage builds on the symptoms experienced in the third stage of sleep deprivation (48 hours without sleep). At this point, an individual will be increasingly accident-prone, with a severe negative impact on their decision-making abilities. They may also experience hallucinations, perceptual distortions, increased irritability, and temporal disorientation.

The second stage of sleep deprivation (36 hours without sleep) is marked by an overwhelming urge to sleep, referred to as "sleep drunkenness". The individual will also experience microsleeps, which are brief episodes of unconsciousness, and increased appetite and extreme fatigue.

Finally, the first stage of sleep deprivation (24 hours without sleep) is characterised by feelings of tiredness and exhaustion. An individual will experience reduced alertness, impaired concentration, and fatigue. They will also be at an increased risk of errors and accidents in everyday tasks.

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