Sleep deprivation can occur after just 24 hours of no sleep. However, the longer you spend awake, the more severe — and less tolerable — symptoms become.
People need sleep to survive. Sleep allows your body to repair itself and perform essential biological functions. Adults need about 7 to 8 hours of sleep each night. But sometimes, work and lifestyle factors may disrupt your ability to sleep.
When you get less sleep than needed or no sleep at all, it’s called sleep deprivation.
For most people, a short bout of sleep deprivation isn’t a cause for concern. But frequent or prolonged sleep deprivation can cause serious health issues.
Lack of sleep can lead to poor cognitive function, increased inflammation, and reduced immune function. If sleep deprivation continues, it may increase your risk for chronic disease.
In general, there are five stages of sleep deprivation. The stages are usually divided into 12-hour or 24-hour increments. The symptoms usually get worse the longer you stay awake.
There isn’t a universal timeline for sleep deprivation.
However, the general stages are determined by how many hours of sleep you’ve missed. The symptoms of sleep deprivation tend to get worse in each stage.
Here’s what might happen to your body during sleep deprivation:
Stage 1: After 24 hours
It’s common to miss 24 hours of sleep. It also won’t cause major health problems, but you can expect to feel tired and “off.”
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Staying awake for 24 hours may cause symptoms like:
- increased risk of stress
- decreased alertness
- impaired concentration
- brain fog
- reduced coordination
- increased risk of mistakes or accidents
- food cravings
- puffy eyes
- dark undereye circles
Stage 2: After 36 hours
When you miss 36 hours of sleep, your symptoms become more intense. You’ll have an overwhelming urge to sleep.
You may start to have microsleeps, or brief periods of sleep, without realizing it. A microsleep usually lasts up to 30 seconds.
Different parts of your brain will have a hard time communicating with each other. This severely impairs your cognitive performance, causing symptoms like:
- impaired memory
- difficulty learning new information
- behavioral changes
- impaired decision-making
- difficulty processing social cues
- slow reaction time
- increased errors
You’re also more likely to experience physical effects like:
- increased appetite
- increased inflammation
- impaired immune function
- extreme fatigue
Stage 3: After 48 hours
Missing sleep for 48 hours is known as extreme sleep deprivation. At this point, it’s even harder to stay awake. You’re more likely to have microsleeps.
You might even begin to hallucinate. This occurs when you see, hear, or feel things that aren’t actually there.
Other possible effects include:
- heightened stress levels
- increased irritability
- extreme fatigue
Stage 4: Awake for 72 hours
After 3 days of sleep loss, your urge to sleep will get worse. You may experience more frequent, longer microsleeps.
The sleep deprivation will significantly impair your perception. Your hallucinations might become more complex. You may also have:
- disordered thinking
Stage 5: Awake for 96 hours or more
After 4 days, your perception of reality will be severely distorted. Your urge for sleep will also feel unbearable.
If you miss so much sleep that you’re unable to interpret reality, it’s called sleep deprivation psychosis.
Typically, sleep deprivation psychosis goes away once you get enough sleep.
It’s possible to recover from sleep deprivation by sleeping more.
You can start by going to bed early rather than sleeping in late. It’s also a good idea to get at least 7 to 8 hours of rest each night. This will help your body get back on schedule.
It can take days or weeks to recover from a bout of sleep deprivation. Just 1 hour of sleep loss requires 4 days to recover.
The longer you’ve been awake, the longer it will take to get back on track.
The best treatment depends on how much sleep you’ve missed. Possible options include:
- Napping. If you’ve only lost a few hours of sleep, napping could reduce your symptoms. Avoid napping more than 30 minutes, which might disrupt your ability to sleep at night.
- Good sleep hygiene. Practicing healthy sleep habits is key to preventing and treating sleep deprivation.
- Over-the-counter sleep aids. Over-the-counter (OTC) sleep aids are ideal for the occasional sleepless night. You can develop a tolerance to them, so it’s best to use them sparingly.
- Prescription sleeping pills. Your doctor may prescribe sleeping pills. But like OTC sleep aids, they can become less effective over time.
- Light therapy. If you have severe insomnia, your doctor might suggest light therapy. This treatment is designed to help reset your body’s internal clock.
- Breathing device. If your sleep deprivation is due to sleep apnea, you might be given a device to help you breathe during sleep. A continuous positive airway pressure (CPAP) machine is the most common option.
Healthy sleep hygiene is one of the most effective ways to prevent sleep deprivation. This includes positive lifestyle habits that help you get quality sleep.
Expose yourself to natural light
Natural light exposure helps normalize your body’s production of melatonin, the sleep hormone. This will regulate your body’s internal clock.
Get regular physical activity
Regular exercise will help you feel tired at night. Aim for at least 20 to 30 minutes each day.
Try to work out at least 5 to 6 hours before bedtime. Exercising too late in the day might mess with your ability to sleep at night.
Avoid caffeine later in the day
If you drink caffeinated drinks, have your last cup before noon. It can take 6 hours for caffeine to wear off.
Avoid alcohol before bed
Although alcohol is known to promote sleepiness, it can disrupt the quality of your sleep. Avoid drinking too much alcohol before bedtime.
Avoid electronic screens before bed
It can be tempting to watch a movie or browse social media just before bed. However, the blue light from the screen can stimulate your brain. It also reduces melatonin production.
To avoid these effects, avoid using electronics 30 minutes to 1 hour before bedtime.
Create a calming bedtime routine
A soothing bedtime routine will help your body and mind prepare for sleep. This may include relaxing activities like:
- taking a warm bath
Have a pleasant sleep environment
You’re more likely to get quality sleep if your bedroom is comfortable and relaxing.
To create an ideal sleep environment:
- Turn off electronics, including TVs and smartphones.
- Keep the bedroom cool (between 60 to 67°F, or 16 to 19°C).
- Use a comfortable mattress and pillow. Want suggestions? Browse our market, filled with editor-trusted and expert-verified pillow and mattress recommendations.
- Cover up loud sounds with a fan, humidifier, or white noise machine.
Follow a consistent sleep schedule
Wake up and go to bed at the same time every night, even when you don’t have work. This will help your body maintain a regular schedule.
Avoid foods that disrupt sleep
Some foods take a while to digest. The digestive process can keep you awake, so it’s best to avoid these foods just before bed.
- heavy meals
- fatty or fried foods
- spicy meals
- acidic foods
- carbonated drinks
If you’re too hungry to sleep, choose a light snack like crackers or cereal.
Also, try to eat your last meal several hours before bedtime.
It’s normal to have the occasional sleepless night. But if you still have trouble sleeping after practicing good sleep hygiene, see a doctor.
Seek medical help if you:
- have difficulty falling asleep
- feel tired after getting enough sleep
- wake up several times at night
- experience microsleeps
- experience frequent fatigue
- need to take daily naps
The first stage of sleep deprivation occurs within 24 hours of missed sleep. Most people can tolerate this level of sleep loss.
But as sleep deprivation continues, it becomes increasingly difficult to stay awake. It also impairs your cognitive function and perception of reality.
Fortunately, with proper sleep habits, it’s possible to recover or prevent sleep deprivation. If you still have trouble getting a good night’s rest, visit your doctor.