Sleep Deprivation Stages & Effects

Sleep deprivation is a general term defined as getting an inadequate amount of sleep, although what constitutes a sufficient amount of sleep can differ from person to person. There are different sleep deprivation stages, which can cover total sleep deprivation (TSD) or partial sleep deprivation (PSD). Not getting enough sleep is not a condition in and of itself, but rather the by-product of other conditions or life circumstances. Continued lack of sleep causes a sleep deficit, which can take some time to correct and to readjust to your sleep-wake cycle.[1]

Chronic sleep loss can negatively impact your health. The speed at which your body experiences the effects of sleep loss depends on whether you are experiencing partial sleep deprivation or total sleep deprivation. Sleep deprivation stages become more intense and severe the longer you stay awake.

Partial sleep deprivation

Partial sleep deprivation involves getting fewer hours of sleep or poorer quality sleep than your body and brain need to function optimally. Signs of sleep deprivation, similar in some ways to signs of insomnia, include excessive daytime sleepiness, trouble concentrating, depression, and/or mood swings. Lack of sleep can be a side effect of sleep apnea or other sleep disorders.

The effects of partial sleep deprivation can build over time and add to your sleep debt. This often results in chronic fatigue, lower levels of efficiency, and the occurrence of “microsleeps.” A microsleep is the occurrence of falling asleep for a very short period of time (up to 30 seconds). Even if you are only sleep deprived by one or two hours of sleep, if this happens for a couple nights in a row, you may start to develop sleep deprivation headaches.[2] As your sleep deficit builds up, it starts to mirror the sleep deprivation stages of acute sleep deprivation.

Total sleep deprivation stages

Chronic and prolonged sleep deprivation is dangerous and can be fatal. One of the longest recorded sleep experiments was in 1964, when a teenage boy managed to stay awake for 264 hours, or approximately 11 days.[3] The effects of total sleep deprivation can be broken down into sleep deprivation stages based on how long you have been awake.

Stage 1 of sleep deprivation is usually defined as 24 hours without sleep. According to the CDC, after 24 hours without sleep, your alertness is similar to those with a blood alcohol content of 0.10%. In the United States, the legal limit is 0.08% — this indicates that after 24 hours of not sleeping, it is not safe to operate a motor vehicle, as your reaction and ability to concentrate are compromised.[4] After one night without sleep, you may experience irritability, poor decision making, intense drowsiness and short-term memory problems. Even after just 24 hours without sleep, many people experience raised levels of the stress hormones cortisol and adrenaline.[5]

At Stage 2, or after 48 hours without any sleep, all the symptoms of Stage 1 intensify, as well as bringing on extreme tiredness and worsening cognitive function. During this stage, people often start to experience microsleeps.

Stage 3, or going 72 hours without sleep, magnifies all the previous signs and symptoms of Stages 1 and 2. People may also begin to have difficulty communicating with others and develop paranoia and delusions.

At Stage 4, or more than 96 hours of sleep deprivation, people often begin to have complex hallucinations, mimicking acute psychoses.[6] People are rarely able to stay awake this long without the use of stimulants or other external factors.


What does sleep deprivation do to the brain?

Sleep deprivation effects on the brain are very noticeable and manifest quickly. Sleep deprivation disrupts and slows down the communication between neurons in your brain.[7] It results in impaired memory, an inability to respond to negative stimuli appropriately, difficulty making decisions, and slower cognitive function.

Does it have long-term effects?

Chronic sleep deprivation can have cumulatively negative effects on your health over time.[8] It can increase your chances of obesity, diabetes, or heart disease. It also lowers your immune system and can decrease your sex drive.

Can you pass out from it?

Sleep deprivation can be very dangerous. People who experience sleep deprivation are more likely to faint or spontaneously pass out than those who are well-rested.[9]

What are three effects of sleep deprivation?

Sleep deprivation can have many effects on your mental and physical health. The three most common short-term effects include excessive daytime sleepiness, impaired memory, and difficulty concentrating.

What causes sleeplessness?

 Sleep deprivation or sleeplessness can be caused by traumatic life events, late night work shifts that disrupt your circadian rhythm, medication, or a number of sleep disorders. In order to avoid the negative repercussions of sleeplessness, it is important to identify what is causing it and find the best way to fall asleep for you.

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