13 Sleep Deprivation Symptoms

How do you know if your body is sleep deprived? Sleep deprivation symptoms generally include feeling sluggish and unproductive. You may be unable to focus or have an impaired memory. Some evidence suggests that sleep deprivation causes hunger and weight gain.

About one-third of adults in the United States do not get enough rest or sleep daily. Not getting enough sleep links to many chronic diseases, such as depression, heart disease, obesity, and type 2 diabetes.

Addressing sleep deprivation and getting sleep cycles back on track is essential. Read on to learn about 13 signs and symptoms of sleep deprivation and how to get enough sleep nightly. 

5 Stages of Sleep Deprivation 

The longer you do not sleep, the more sleep deprivation symptoms worsen. Research has found that prolonged sleep deprivation, or 48–96 hours or longer, may cause delirium and hallucinations. Those symptoms typically resolve with sleep.

The five stages of sleep deprivation and their symptoms include:

• After 24 hours: Being awake for 24 hours is similar to having a blood alcohol concentration (BAC) of 0.10%. You may feel sleepy and unable to focus the day after pulling an "all-nighter." Other symptoms include decreased libido and moodiness.
• After 36 hours: You may feel angry, anxious, confused, fatigued, and sleepy after 36 hours without sleep. A lack of sleep decreases energy levels, so you may not be able to complete daily activities as effectively as usual. You may have depersonalization, or feeling detached from your identity, and feel disorientated.
• After 48 hours: Disordered thinking and complex hallucinations may occur after 48 hours of not sleeping. You may have hallucinations that are auditory, visual, or a mix of both. Other sleep deprivation symptoms worsen after 48 hours.
• After 72 hours: Disordered thinking and hallucinations worsen after 72 hours of not sleeping. People who do not sleep for three days often become delirious, resembling acute psychosis.
• After 96 hours: Being awake for four days or longer often worsens delusions. Research has found that people who do not sleep for 96 hours show symptoms that resemble schizophrenia.

1. Hunger

"If the brain is not getting the energy it needs from sleep, it will often try to get it from food," Chris Winter, MD, a neurologist and sleep medicine specialist, told Health. 

Running low on rest can affect ghrelin and leptin, the hunger and satiety hormones. Too much ghrelin makes your body crave fatty and sugary foods, said Dr. Winter. 

"When you're not sleeping properly, you tend to eat more of what you're craving because you're not feeling the signals to stop eating," noted Dr. Winter.

2. Weight Gain

Weight gain is another symptom of sleep deprivation that comes with an increased appetite. With ghrelin and leptin already out of balance, your body may crave fried foods and sweets, which may cause weight gain. 

"When you're tired, you don't watch what you're eating," said Dr. Winter. "You just look for all kinds of things to help you feel more awake."

A lack of sleep may directly affect your metabolism, added Dr. Winter. Your metabolism tends to slow down without proper rest. Research has found that short sleep duration increases the risk of obesity.

3. Memory Issues

A lack of sleep may harm your memory function. Being overtired stops protein synthesis from occurring in the hippocampus in your brain, which controls emotions, learning, and memory.

Some evidence suggests that sleep deprivation may cause oxidative stress, or an imbalance between free radicals and antioxidants in your body. Oxidative stress further impairs learning and memory processes. Vitamin E, a strong antioxidant, may counteract the impact of a lack of sleep on memory.

4. Impulsivity

People tend to act without thinking when they're exhausted, Gail Saltz, MD, a clinical associate professor of psychiatry at the New York Presbyterian Hospital, Weill-Cornell Medical College, told Health. 

"Your ability to say, 'No, I shouldn't have another candy bar' becomes more difficult," said Dr. Saltz.

Impulsivity does not just apply to eating more. You might find yourself doing or saying things you do not necessarily mean, like lashing out at a spouse or ranting at a friend. 

"The main thing is you're less inhibited," Kelly Baron, PhD, a clinical psychologist specializing in behavioral sleep medicine, told Health.

Research has found that sleep deprivation impairs several aspects of cognitive function, such as:

• Attention
• Cognitive flexibility, or the ability to switch between tasks
• Inhibition
• Memory 

A study published in 2016 found that urban adolescents who slept longer than others were less likely to report moderate aggressive physical behavior against their peers.

5. Nausea

A lack of sleep may cause gastrointestinal (GI) symptoms, including nausea. Other GI symptoms may include abdominal pain, constipation, diarrhea, gas, and vomiting.

Research has found that a lack of sleep may cause inflammation of your intestines, making you feel nauseous. Over time, chronic inflammation may lead to or worsen GI illnesses, such as gastroesophageal reflux disease (GERD), which may cause nausea.

6. Difficulty Making Decisions

Lack of sleep may be the culprit if you find managing projects at home and work harder than usual.

"Sleep deprivation can affect speed and higher-level cognitive processing," said Baron. That includes essential functions, such as problem-solving or time management, which become difficult.

Research has found that sleep deprivation can negatively impact financial decisions and lead to lost gains. A study published in 2015 reported that even one night of sleep deprivation could alter economic choices.

7. Impaired Motor Skills

We all trip occasionally, but you may be too tired to focus on where you are going if you trip a few times in one day. Sleep deprivation may negatively affect your motor skills.

"When you're tired, there's a lapse in how you neurologically function, in general," said Dr. Winter. You may have difficulty with movement if your concentration and reaction time decreases,

"When you walk up and down the stairs, there's a lot of processing going on there," added Dr. Winter. "When sleep-deprived, you can't process particularly well."

8. Emotional Distress

You may feel your emotions are out of control when you have missed sleep. Things that normally have not gotten you worked up in the past—a big work deadline or a tear-jerking movie—may provoke anxiety, sadness, or anger. 

"You become over-reactive to emotional stimuli," said Dr. Baron.

Sleep deprivation may affect your emotions in the opposite way: "People can get slap-happy and giddy, as well," added Dr. Baron.

A review published in 2018 found that people who get adequate sleep nightly have fewer aggressive behaviors and emotional outbursts, such as anger.

9. Frequent Illnesses

Poor sleep may weaken your immune system. 

"There can be significant issues in terms of your body's ability to fight off infections," said Dr. Winter. You may find it harder to shake off a cold than normal.

A study published in 2015 quarantined 164 healthy men and women and gave them nasal drops with rhinovirus. The researchers monitored the participants over five days for the development of a cold. The data showed short sleep duration increased susceptibility to the common cold.

Your immune system produces cytokines while you sleep. Cytokines are proteins that protect against infections and inflammation. The researchers suspected that a few nights of poor sleep might lower the production of cytokines, thereby weakening its defenses against viruses.

10. Vision Problems

"When fatigued, you're not able to control the muscles of the eye as well," Steven Shanbom, MD, an ophthalmologist based in Michigan, told Health. 

Skimping on sleep tires out the ciliary muscle, which helps your eyes focus. As a result, you may have a harder time reading up close than usual, said Dr. Shanbom. 

"Many people have a muscle imbalance where their eyes don't track well together," noted Dr. Shanbom.

Your eyes can typically compensate on their own if you are well-rested. In contrast, a lack of sleep makes the misalignment hard to control, potentially resulting in double vision.

11. Skin Issues

Of all the places on your body, your face may show your age the most if you do not get a good night's sleep. 

"Your body produces collagen while you're sleeping. Getting enough sleep helps skin restore itself," Debra Jaliman, MD, a dermatologist and assistant clinical professor of dermatology at the Icahn School of Medicine at Mount Sinai, told Health. "The cells regenerate, and DNA repair is also boosted during this period."

A study published in 2015 found that poor sleepers had higher levels of transepidermal water loss than others, which ages the skin. The researchers noted that adequate sleep increases skin barrier recovery by nearly 30%.

You may perceive your appearance and physical attractiveness better than usual if you sleep enough.

"When a good night's sleep is hindered, you will look significantly more fatigued," Flora Kim, MD, a dermatologist based in Texas, told Health. Signs of fatigue include dark undereye circles and droopy eyelids.

Sleep deprivation may cause acne due to circadian disruption, said Dr. Kim. Circadian disruption is an abrupt biological change that creates an imbalance in your skin.

People with sleep deprivation tend to offset their fatigue with increased caffeine intake or smoking, which may contribute to acne.

12. Issues With Growth

Adequate sleep and successful growth go hand in hand. That's why infants sleep so much during their first few years of life. Their bodies are undergoing rapid growth. Generally, children aged 5 to 10 need 10–11 hours of sleep per night, and those aged 10 to 17 need about eight to nine hours.

"The human growth hormone [HGH] kicks in while we are sleeping," said Dr. Jaliman. 

HGH speeds up your skin's repair and cell regeneration, added Dr. Jailman. Circulating amounts of HGH significantly elevate while you are sleeping. A lack of sleep may leave you with less HGH than usual, perhaps stifling your growth. Getting plenty of rest is essential to give your growth plates the best chance possible.

13. Nodding Off

You may be experiencing microsleep if you nod off for a few seconds without realizing it. Microsleep is your body forcing you to get the rest you need.

"The brain says, 'I don't care what you want to do. We are going to sleep,'" said Dr. Winter. 

The big problem is that microsleep can be extremely dangerous if you happen to be driving. The National Highway Traffic Safety Administration (NHTSA) estimated that 684 deaths occurred due to driving while drowsy in 2021.

Pull over and rest until you feel up to retaking the wheel if you ever feel sleepy on the road.

Signs in Infants and Children

Infants and children must get enough sleep to support their growth and overall health, including their brain and immune health.

Signs that an infant is tired include:

• Fussing
• Looking away from you
• Rubbing their eyes
• Yawning

An infant may have trouble falling asleep or will not stay asleep for long periods if they are overly tired.

Research has found signs of a lack of sleep in children may include:

• Aggressive behavior
• Anxiety and depression
• Impaired memory and learning
• Impulsivity
• Poor decision-making
• Problems solving conflicts
• Stress
• Trouble thinking

A study published in 2022 reported that children who were sleep deprived had less gray matter in their brains than those who got enough sleep. Gray matter controls your attention, inhibitions, and memory.

Sleep Recommendations 

Sleep helps your body process information and memories, repairs cells, and supports your immune system. Getting enough sleep each night allows your body to carry out those functions.

How much sleep you need depends on your age, such as:

Effects of Sleep Deprivation

Occasionally missing a few hours of sleep will likely not affect you—besides feeling sleepy the following day. In contrast, regularly not getting enough sleep can significantly impact your mental and physical health.

Not getting enough sleep may lead to several adverse effects, such as:

• Anxiety and depression
• Impaired memory
• Inability to react quickly
• Increased risk of accidents, such as while driving
• Irritability
• Poor decision-making
• Strained relationships
• Trouble thinking

Over time, a lack of sleep may impact your physical health and raise the risk of health conditions like:

• Heart disease
• High blood pressure
• Kidney disease
• Obesity
• Stroke
• Type 2 diabetes

Sleep deprivation may cause low muscle mass, stunted growth, and weak immunity in children.

A Quick Review

You may be unable to focus or feel sluggish and unenergized if you are sleep deprived. A lack of sleep may increase the risk of accidents, frequent illnesses, vision problems, and other health concerns. 

Getting enough sleep supports your mental and physical health by processing memories and strengthening your immune system. Adults need about seven to eight hours of sleep nightly. Go to bed and wake up at the same times daily to avoid sleep deprivation. Avoid caffeine during the late afternoon and evening, and unwind with calming activities to help yourself relax.