HomeFAQsWhat are the effects of sleep deprivation on the human body?

What are the effects of sleep deprivation on the human body?

Consequences of Sleep Deprivation

From “Sleep for Success” (in press) By James B. Maas, Ph.D., Rebecca S. Robbins, and Sharon R. Driscoll, Cornell University

© 2010. All rights reserved.

What does it mean to be “sleep deprived”?
You are sleep deprived if you’re not meeting your personal sleep need, which for most adults is between 7.5 and 9 hours per night and for high school and college students is 9.25 hours per night. And the term “sleep deprived” certainly applies to anyone who has difficulty falling asleep or staying asleep, waking up too early, and/or has poor sleep quality. Most Americans are at least modestly sleep deprived. While the average person claims to get 7.1 hours of sleep per night, studies at the University of Chicago and Cornell University found that those claiming 7 to 8 hours per night really slept closer to 6. It seems we’re so sleep-deprived, we aren’t even aware of how little we rest.

What are the signs of sleep deprivation?
Predictably, the most common symptom is fatigue. But as obvious as that seems, many people become so accustomed to feeling chronically tired that they accept it as normal. This same attitude is often applied to other symptoms such as mood swings, irritability, anxiety and difficulty concentrating, remembering, learning and interacting socially. You may feel you’re a loner, a slow-learner, or just not a vibrant or ambitious person, when in fact your fatigue has created a shell around your true personality and abilities. People don’t recognize that sleepiness is not “normal,” and something must be done to break the cycle. Signs of chronic sleep deprivation can also include frequent infections/illnesses, blurred vision, changes in appetite, and depression. While these symptoms may be relatively minor and seem unrelated at first, they can be the precursors of life-shortening afflictions. Without proper treatment, they can grow to negatively impact your health and quality of life.

What are the most common causes of sleep deprivation?
The biggest and most prevalent is our society’s persistent belief that sleep is a luxury rather than a necessity. When it seems there just aren’t enough hours in the day, sleep is the first thing we cut, though ironically if we slept more, we’d be more efficient and productive. The advent of the Internet, buzzing Blackberrys and 24/7 entertainment has compounded it. Abusing sleep with blissful machismo is now deeply engrained in our global society.
Beyond this general notion, there are many specific contributing factors to sleep deprivation. Temporary sleep-loss, for instance, is often triggered by passing stressors, such as a headache, toothache, indigestion, back problems, cold, flu or jetlag. While these causes are certainly real and frustrating, they’re relatively easy to treat. Anxiety is the most common cause of short-term sleep-loss, and it can last for weeks. Nervousness about money, your marriage or relationship, losing or finding a job, your weight or other health concerns and even boredom, can all make you toss and turn.
Long-term sleep loss is occasionally caused by environmental factors – your job, if you’re a night-shift worker; where you live, if it’s in a noisy area – but it more commonly stems from medical conditions such as arthritis, diabetes, epilepsy, ulcers and heart disease (among others), as well as consistent drug (including caffeine) or alcohol use. There are also a number of sleep-specific medical conditions that can severely impact and disrupt rest. These include sleep apnea, narcolepsy, restless leg syndrome and upwards of 86 other distinguishable disorders.
More than a third of people who suffer from chronic insomnia also have psychiatric conditions such as depression and schizophrenia, as well as obsessive-compulsive disorder, anxieties or phobias. Sleep and psychiatric problems tend to go hand-in-hand – when you’re not sleeping well, life appears more grim; when life appears grim, it’s harder to rest. Trouble sleeping can even be an early sign or forthcoming psychiatric problems, so it’s important to talk to a doctor if symptoms arise or persist. For most patients, when an underlying mental condition is treated, sleep habits improve.

What are the physical effects of not sleeping?
Daytime drowsiness deteriorates: Performance plummets and cognition wanes when deprived of sleep.
Susceptibility to microsleeps : these are brief episodes of sleep that you’re unaware of and that occur during waking hours. Lasting only a few seconds, microsleeps can produce inattention, resulting in accidents and injury.
Colds and flu increase: Dr. Jan Born at the University of Luebeck in Germany found that people who sleep less than 6 hours per night have 50% less resistance to viral infection than those getting 8 hours of sleep. In addition, Dr. Sheldon Cohen of Carnegie Mellon University found that those sleeping less than 7 hours per night are three times more likely to get a cold than longer-sleepers.
Weight gain: You might think that spending more time in bed makes you lazy, but not spending enough time in bed can also make you fat. To the contrary; lack of sleep lowers leptin levels in the brain and raises ghrelin levels in the stomach. These hormones are responsible for appetite regulation. So when you’re sleep deprived, you’re more likely to overeat – craving carbs, sugars and junk food. Researchers at Columbia University as well as the University of Chicago have found people who sleep 5 hours per night have a 50% higher chance of being obese, while those who sleep 6 hours have a 23% greater risk. Professor Francesco Cappuccio at the University of Warwick’s Medical School, found that less sleep is associated with an almost two-fold increase in obesity – a trend that he says is detectable in children as young as five. The research also linked short sleep with a higher body-mass index (BMI) and waist circumference over time.
Diabetes: A study at the University of Chicago involving healthy young men with no risk factor for diabetes found that after just one week of inadequate sleep, they were in a pre-diabetic state. Researchers attributed the result to overactive central nervous systems (caused by not sleeping), which affected the ability of the pancreas to produce enough insulin to adequately regulate glucose levels. The current epidemic in diabetes may be connected to the epidemic in sleep deprivation. We now have an epidemic of early onset childhood diabetes, and it appears to be linked to obesity and lack of sleep.
Heart disease: Not sleeping often causes the body to produce more stress hormones. Such an imbalance can lead to arteriosclerosis, which can cause heart attacks and stroke, in addition to hypertension, muscle loss, increased fat storage, loss of bone mass, and lower production of growth hormone and testosterone. In addition, short-sleepers miss out on REM sleep (predominant between the 7th and 8th hours of the night), during which time the heart pumps more blood to the muscles. This helps it relax as blood pressure falls. So by cutting back on sleep, we’re preventing this innate regulating system from doing its job.
Cancer: Women who exercise regularly and were generally healthy had a 47% higher risk of cancer if they were sleeping fewer than 7 hours. Research at Stanford University also found that good sleep habits can be a valuable weapon in fighting cancers, citing melatonin (released during sleep) and cortisol production (involved in regulating immune system activity) as vital players in patient recovery. Night-shift workers (both male and female) have a 35% higher risk of colorectal cancer. Why? According to the International Agency for Research on Cancer, shift-work is not a “possible” but a “probable” carcinogen, due to too much light exposure and lack of melatonin secretion in your brain because you are not sleeping.

What are the behavioral effects of sleep deprivation?

  • Mood shifts, including depression and irritability
  • Stress, anxiety and loss of coping skills.
  • Socializing less.
  • Sub-par mental functioning/perception
  • Concentration problems
  • Difficulties with
  • Being unable to think logically and critically
  • Failing to analyze and assimilate new information
  • Reduced ability to communicate
  • Lower creativity
  • Impaired motor skills and coordination

How can I “cure” my sleep deprivation?
It’s simple: Learn to sleep better and sleep more. And here is where we come in! Most people need to rest just one extra hour per night to stay completely alert all day. It’ll take a few weeks to effectively change your schedule to accommodate this, but eventually you should be waking up naturally without an alarm clock. After just a few nights of meeting your personal sleep quotient by improving your sleep strategies, you should feel a notable difference.


Jim Maas
Weiss Presidential Fellow and Professor
Psychology, Cornell University
Ph.D. Cornell University
Research Area:
Sleep and daytime performance

Wife Nancy, sons Daniel and Justin
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