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All-night study sessions, important business deals, new babies - most people will experience a taste of sleep deprivation at some point in life. While the occasional lack of sleep may not seem like a big deal, the impact of sleep deprivation can be intense and its effects can linger. In extreme circumstances, sleep deprivation can ultimately lead to death.

"As a society, as families and individuals, we have not yet fully appreciated the importance of sleep," says Terry Cralle, RN, a certified clinical sleep educator in Fairfax, Virginia. "Sleep, along with diet and exercise, constitutes the very foundation of good health." In fact, she says, the three are so interconnected that each needs to be a priority.

Chronic poor sleep puts us at increased risk for serious medical conditions, such as obesity, heart disease, and diabetes. During sleep, our bodies secrete hormones that help control appetite, metabolism, and glucose processing. Poor sleep can lead to an increase in the body's production of cortisol, also known as the stress hormone. In addition, skimping on sleep seems to throw other body hormones out of whack. Less insulin is released after you eat, and this along with the increased cortisol may lead to too much glucose in the bloodstream and thus an increased risk for type 2 diabetes.

But how much sleep do I really need? Everyone is different, but according to the Centers for Disease Control and Prevention (CDC), adults should get between 7 and 9 hours of sleep each night. ( 1) And contrary to popular belief, sleeping an extra hour or two on the weekends can not make up for the lost sleep you may be experiencing over the course of a busy week. It could also throw off your internal body clock and possibly lead to Sunday night insomnia. Sticking to a consistent sleep schedule is the best way to regulate the body's clock.

While pulling an all-nighter (or longer) might seem like a feat worth celebrating, here's a look at what you're putting your body through.

At 24 Hours: Impaired Coordination, Memory, and Judgment

Scott Kelley, a 10-year Army veteran, knows about sleep deprivation. With multiple deployments under his belt, Kelley has had many instances of being awake longer than 24 hours in the field. "There were several occasions in Afghanistan and Iraq where I had just finished up 15 to 20 hours of working, got back to my hooch, and then either a rocket attack would come in or a critical mission would be called," he says.

Kelley's military training and adrenaline-filled environment seemed enough to keep him focused and alert at this early stage of sleep deprivation. But what happens in more normal circumstances is surprising. The consequences of sleep deprivation at 24 hours is comparable to the cognitive impairment of someone with a blood alcohol content of 0.10 percent, according to a study published in the International Journal of Occupational Medicine and Environmental Health. ( 2) "Judgment is affected, memory is impaired, there is deterioration in decision-making, and a decline in eye-hand coordination," Cralle says. "You're more emotional, attention is decreased, hearing is impaired, and there is an increase in your risk of death from a fatal accident."

At 36 Hours: Physical Health Starts to Be Negatively Impacted

Now your health begins to be at risk. High levels of inflammatory markers are in the bloodstream, says Cralle, which can eventually lead to cardiovascular disease and high blood pressure. Additionally, hormones are affected - your emotions can be all over the place.

Once Kelley reached 36 hours without sleep, his head started buzzing as though he were dehydrated, and he began to lose motivation. His responses were dependent on his training, and in some instances, he functioned on autopilot and lost chunks of time. Once, he was called back to duty just as he was about to go to sleep after 36 hours on the job, he recounted. "After a quick briefing, I grabbed my gear and flew out by helicopter, got dropped off in the middle of nowhere, and hiked out to the FOB [forward operating base]. The next day, we rode back through the most dangerous road in central Afghanistan, but I don't remember leaving the FOB or hardly anything that happened until I got back to the base."

At 48 Hours: Microsleeps and Disorientation

After two days of no sleep, Cralle says, the body begins compensating by shutting down for microsleeps, episodes that last from half a second to half a minute and are usually followed by a period of disorientation. "The person experiencing a microsleep falls asleep regardless of the activity they are engaged in," she says. Microsleeps are similar to blackouts, and a person experiencing them is not consciously aware that they're occurring.

Kelley experienced microsleeps during this phase of sleep deprivation. "Around 48 hours or so, my mind starts to slip into neutral sometimes, and I find myself staring off into the distance if I don't maintain focus," he says.

At 72 Hours: Major Cognitive Deficits and Hallucinations

Expect significant deficits in concentration, motivation, perception, and other higher mental processes after many sleepless hours, Cralle says.

"Even simple conversations can be a chore," notes Kelley. This is when the mind is ripe for hallucinations. Kelley recalled a time he was on guard duty and repeatedly saw someone standing with a rifle in the woods, ready to sneak into camp. Upon closer inspection, he determined he was actually looking at a branch and shadows.

Involuntary Sleep Deprivation: Causes and Symptoms

Not all instances of sleep deprivation are voluntary. Insomnia, sleep apnea, restless legs syndrome, night terrors, sleepwalking, and other problems can affect sleep. See a sleep specialist if you experience any of the following, suggests Cralle:

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What Happens to You When You Don't Sleep for Days

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All-night study sessions, important business deals, new babies - most people will experience a taste of sleep deprivation at some point in life. While the occasional lack of sleep may not seem like a big deal, the impact of sleep deprivation can be intense and its effects can linger.

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Until the 1950s, most people thought of sleep as a passive, dormant part of our daily lives. We now know that our brains are very active during sleep. Moreover, sleep affects our daily functioning and our physical and mental health in many ways that we are just beginning to understand. So "What Is Sleep?"...
Nerve-signaling chemicals called neurotransmitters control whether we are asleep or awake by acting on different groups of nerve cells, or neurons, in the brain. Neurons in the brainstem, which connects the brain with the spinal cord, produce neurotransmitters such as serotonin and norepinephrine that keep some parts of the brain active while we are awake. Other neurons at the badeepse of the brain begin signaling when we fall asleep. These neurons appear to "switch off" the signals that keep us awake. Research also suggests that a chemical called adenosine builds up in our blood while we are awake and causes drowsiness. This chemical gradually breaks down while we sleep.

What Are The Stages of Sleep?

During sleep, we usually pass through five phases of sleep: stages 1, 2, 3, 4, and REM (rapid eye movement) sleep. These Stages of Sleep progress in a cycle from stage 1 to REM sleep, then the cycle starts over again with stage 1. We spend almost 50 percent of our total sleep time in stage 2 sleep, about 20 percent in REM sleep, and the remaining 30 percent in the other stages. Infants, by contrast, spend about half of their sleep time in REM sleep.

Stage One Sleep

During stage 1, which is light sleep, we drift in and out of sleep and can be awakened easily. Our eyes move very slowly and muscle activity slows. People awakened from stage 1 sleep often remember fragmented visual images. Many also experience sudden muscle contractions called hypnic myoclonia or hypnic jerks, often preceded by a sensation of starting to fall. These sudden movements are similar to the "jump" we make when startled.

Stage Two Sleep

When we enter stage 2 sleep, our eye movements stop and our brain waves (fluctuations of electrical activity that can be measured by electrodes) become slower, with occasional bursts of rapid waves called sleep spindles.

Stage Three, Four & REM Sleep

In stage 3, extremely slow brain waves called delta wavesbegin to appear, interspersed with smaller, faster waves. By stage 4, the brain produces delta waves almost exclusively. It is very difficult to wake someone during stages 3 and 4, which together are called deep sleep. There is no eye movement or muscle activity. People awakened during deep sleep do not adjust immediately and often feel groggy and disoriented for several minutes after they wake up. Some children experience bedwetting, night terrors, or sleepwalking during deep sleep.

When we switch into REM sleep, our breathing becomes more rapid, irregular, and shallow, our eyes jerk rapidly in various directions, and our limb muscles become temporarily paralyzed. Our heart rate increases, our blood pressure rises, and males develop penile erections. When people awaken during REM Sleep, they often describe bizarre and illogical tales - dreams.

The first REM sleep period usually occurs about 70 to 90 minutes after we fall asleep. A complete sleep cycle takes 90 to 110 minutes on average. The first sleep cycles each night contain relatively short REM periods and long periods of deep sleep. As the night progresses, REM sleep periods increase in length while deep sleep decreases. By morning, people spend nearly all their sleep time in stages 1, 2, and REM.

People awakened after sleeping more than a few minutes are usually unable to recall the last few minutes before they fell asleep. This sleep-related form of amnesia is the reason people often forget telephone calls or conversations they've had in the middle of the night. It also explains why we often do not remember our alarms ringing in the morning if we go right back to sleep after turning them off.

What Is Sleep & What Influences The Quality & Length Of Sleep?

Since sleep and wakefulness are influenced by different neurotransmitter signals in the brain, foods and medicines that change the balance of these signals affect whether we feel alert or drowsy and how well we sleep. Caffeinated drinks such as coffee and drugs such as diet pills and decongestants stimulate some parts of the brain and can cause insomnia, or an inability to sleep. Many antidepressants suppress REM sleep. Heavy smokers often sleep very lightly and have reduced amounts of REM sleep. They also tend to wake up after 3 or 4 hours of sleep due to nicotine withdrawal. Many people who suffer from insomnia try to solve the problem with alcohol - the so-called night cap. While alcohol does help people fall into light sleep, it also robs them of REM and the deeper, more restorative stages of sleep. Instead, it keeps them in the lighter stages of sleep, from which they can be awakened easily.
People lose some of the ability to regulate their body temperature during REM, so abnormally hot or cold temperatures in the environment can disrupt this stage of sleep. If our REM sleep is disrupted one night, our bodies don't follow the normal sleep cycle progression the next time we doze off. Instead, we often slip directly into REM sleep and go through extended periods of REM until we "catch up" on this stage of sleep.
People who are under anesthesia or in a coma are often said to be asleep. However, people in these conditions cannot be awakened and do not produce the complex, active brain wave patterns seen in normal sleep. Instead, their brain waves are very slow and weak, sometimes all but undetectable.
TIP: Having a comfortable bedroom and mattress are also important for facilitating good sleep. Have a quiet bedroom. Mattresses and beds should be comfortable for you and your bed partner. There are a lot of changes you can make to help you Get better sleep

How Much Sleep Do We Need?

The amount of sleep each person needs depends on many factors, including age. Infants generally require about 16 hours a day, while teenagers need about 9 hours on average. For most adults, 7 to 8 hours a night appears to be the best amount of sleep, although some people may need as few as 5 hours or as many as 10 hours of sleep each day. Women in the first 3 months of pregnancy often need several more hours of sleep than usual. The amount of sleep a person needs also increases if he or she has been deprived of sleep in previous days. Getting too little sleep creates a "sleep debt," which is much like being overdrawn at a bank. Eventually, your body will demand that the debt be repaid. We don't seem to adapt to getting less sleep than we need; while we may get used to a sleep-depriving schedule, our judgment, reaction time, and other functions are still impaired.

How Important Is Sleep?

People tend to sleep more lightly and for shorter time spans as they get older, although they generally need about the same amount of sleep as they needed in early adulthood. About half of all people over 65 have frequent sleeping problems, such as insomnia, and deep sleep stages in many elderly people often become very short or stop completely. This change may be a normal part of aging, or it may result from medical problems that are common in elderly people and from the medications and other treatments for those problems.
Experts say that if you feel drowsy during the day, even during boring activities, you haven't had enough sleep. If you routinely fall asleep within 5 minutes of lying down, you probably have severe sleep deprivation, possibly even a sleep disorder. Microsleeps, or very brief episodes of sleep in an otherwise awake person, are another mark of sleep deprivation. In many cases, people are not aware that they are experiencing microsleeps. The widespread practice of "burning the candle at both ends" in western industrialized societies has created so much sleep deprivation that what is really abnormal sleepiness is now almost the norm.

Negative Impact of Sleep Deprivation

Many studies make it clear that sleep deprivation is dangerous. Sleep-deprived people who are tested by using a driving simulator or by performing a hand-eye coordination task perform as badly as or worse than those who are intoxicated. Sleep deprivation also magnifies alcohol's effects on the body, so a fatigued person who drinks will become much more impaired than someone who is well-rested.
Driver fatigue is responsible for an estimated 100,000 motor vehicle accidents and 1500 deaths each year, according to the National Highway Traffic Safety Administration. Since drowsiness is the brain's last step before falling asleep, driving while drowsy can - and often does - lead to disaster. Caffeine and other stimulants cannot overcome the effects of severe sleep deprivation. The National Sleep Foundation says that if you have trouble keeping your eyes focused, if you can't stop yawning, or if you can't remember driving the last few miles, you are probably too drowsy to drive safely.

What Does Sleep Do For Us?

Although scientists are still trying to learn exactly why people need sleep, animal studies show that sleep is necessary for survival. For example, while rats normally live for two to three years, those deprived of REM sleep survive only about 5 weeks on average, and rats deprived of all sleep stages live only about 3 weeks. Sleep-deprived rats also develop abnormally low body temperatures and sores on their tail and paws. The sores may develop because the rats' immune systems become impaired. Some studies suggest that sleep deprivation affects the immune system in detrimental ways.

Impact of Sleep on The Nervous System

Sleep appears necessary for our nervous systems to work properly. Too little sleep leaves us drowsy and unable to concentrate the next day. It also leads to impaired memory and physical performance and reduced ability to carry out math calculations. If sleep deprivation continues, hallucinations and mood swings may develop. Some experts believe sleep gives neurons used while we are awake a chance to shut down and repair themselves. Without sleep, neurons may become so depleted in energy or so polluted with byproducts of normal cellular activities that they begin to malfunction. Sleep also may give the brain a chance to exercise important neuronal connections that might otherwise deteriorate from lack of activity.

How Does Sleep Affect Growth In Children?

Deep sleep coincides with the release of growth hormone in children and young adults. Many of the body's cells also show increased production and reduced breakdown of proteins during deep sleep. Since proteins are the building blocks needed for cell growth and for repair of damage from factors like stress and ultraviolet rays, deep sleep may truly be "beauty sleep."
Activity in parts of the brain that control emotions, decision-making processes, and social interactions is drastically reduced during deep sleep, suggesting that this type of sleep may help people maintain optimal emotional and social functioning while they are awake. A study in rats also showed that certain nerve-signaling patterns which the rats generated during the day were repeated during deep sleep. This pattern repetition may help encode memories and improve learning.

Dreaming and REM Sleep

We typically spend more than 2 hours each night dreaming. Scientists do not know much about how or why we dream. Sigmund Freud, who greatly influenced the field of psychology, believed dreaming was a "safety valve" for unconscious desires. Only after 1953, when researchers first described REM in sleeping infants, did scientists begin to carefully study sleep and dreaming. They soon realized that the strange, illogical experiences we call dreams almost always occur during REM sleep. While most mammals and birds show signs of REM sleep, reptiles and other cold-blooded animals do not.
REM sleep begins with signals from an area at the base of the brain called the pons. These signals travel to a brain region called the thalamus, which relays them to the cerebral cortex - the outer layer of the brain that is responsible for learning, thinking, and organizing information. The pons also sends signals that shut off neurons in the spinal cord, causing temporary paralysis of the limb muscles. If something interferes with tis paralysis, people will begin to physically "act out" their dreams - a rare, dangerous problem called REM sleep behavior disorder. A person dreaming about a ball game, for example, may run headlong into furniture or blindly strike someone sleeping nearby while trying to catch a ball in the dream.
REM sleep stimulates the brain regions used in learning. This may be important for normal brain development during infancy, which would explain why infants spend much more time in REM sleep than adults. Like deep sleep, REM sleep is associated with increased production of proteins. One study found that REM sleep affects learning of certain mental skills. People taught a skill and then deprived of non-REM sleep could recall what they had learned after sleeping, while people deprived of REM sleep could not.

Is There Meaning In Dreams?

Some scientists believe dreams are the cortex's attempt to find meaning in the random signals that it receives during REM sleep. The cortex is the part of the brain that interprets and organizes information from the environment during consciousness. It may be that, given random signals from the pons during REM sleep, the cortex tries to interpret these signals as well, creating a "story" out of fragmented brain activity.

Sleep and Circadian Rhythms

Circadian rhythms are regular changes in mental and physical characteristics that occur in the course of a day ( circadian is Latin for "around a day"). Most circadian rhythms are controlled by the body's biological "clock." This clock, called the suprachiasmatic nucleus or SCN , is actually a pair of pinhead-sized brain structures that together contain about 20,000 neurons. The SCN rests in a part of the brain called the hypothalamus, just above the point where the optic nerves cross. Light that reaches photoreceptors in the retina (a tissue at the back of the eye) creates signals that travel along the optic nerve to the SCN.
Signals from the SCN travel to several brain regions, including the pineal gland, which responds to light-induced signals by switching off production of the hormone melatonin. The body's level of melatonin normally increases after darkness falls, making people feel drowsy. The SCN also governs functions that are synchronized with the sleep/wake cycle, including body temperature, hormone secretion, urine production, and changes in blood pressure.
By depriving people of light and other external time cues, scientists have learned that most people's biological clocks work on a 25-hour cycle rather than a 24-hour one. But because sunlight or other bright lights can reset the SCN, our biological cycles normally follow the 24-hour cycle of the sun, rather than our innate cycle. Circadian rhythms can be affected to some degree by almost any kind of external time cue, suchas the beeping of your alarm clock, the clatter of a garbage truck, or the timing of your meals. Scientists call external time cues zeitgebers (German for "time givers").
When travelers pass from one time zone to another, they suffer from disrupted circadian rhythms, an uncomfortable feeling known as jet lag. For instance, if you travel from California to New York, you "lose" 3 hours according to your body's clock. You will feel tired when the alarm rings at 8 a.m. the next morning because, according to your body's clock, it is still 5 a.m. It usually takes several days for your body's cycles to adjust to the new time.
To reduce the effects of jet lag, some doctors try to manipulate the biological clock with a technique called light therapy. They expose people to special lights, many times brighter than ordinary household light, for several hours near the time the subjects want to wake up. This helps them reset their biological clocks and adjust to a new time zone.
Symptoms much like jet lag are common in people who work nights or who perform shift work. Because these people's work schedules are at odds with powerful sleep-regulating cues like sunlight, they often become uncontrollably drowsy during work, and they may suffer insomnia or other problems when they try to sleep. Shift workers have an increased risk of heart problems, digestive disturbances, and emotional and mental problems, all of which may be related to their sleeping problems. The number and severity of workplace accidents also tend to increase during the night shift. Major industrial accidents attributed partly to errors made by fatigued night-shift workers include the Exxon Valdez oil spill and the Three Mile Island and Chernobyl nuclear power plant accidents. One study also found that medical interns working on the night shift are twice as likely as others to misinterpret hospital test records, which could endanger their patients. It may be possible to reduce shift-related fatigue by using bright lights in the workplace, minimizing shift changes, and taking scheduled naps.
Many people with total blindness experience life-long sleeping problems because their retinas are unable to detect light. These people have a kind of permanent jet lag and periodic insomnia because their circadian rhythms follow their innate cycle rather than a 24-hour one. Daily supplements of melatonin may improve night-time sleep for such patients. However, since the high doses of melatonin found in most supplements can build up in the body, long-term use of this substance may create new problems. Because the potential side effects of melatonin supplements are still largely unknown, most experts discourage melatonin use by the general public.

Sleep & Disease

Sleep and sleep-related problems play a role in a large number of human disorders and affect almost every field of medicine. For example, problems like stroke and asthma attacks tend to occur more frequently during the night and early morning, perhaps due to changes in hormones, heart rate, and other characteristics associated with sleep. Sleep also affects some kinds of epilepsy in complex ways. REM sleep seems to help prevent seizures that begin in one part of the brain from spreading to other brain regions, while deep sleep may promote the spread of these seizures. Sleep deprivation also triggers seizures in people with some types of epilepsy.

Sleep's Impact on the Immune System

Neurons that control sleep interact closely with the immune system. As anyone who has had the flu knows, infectious diseases tend to make us feel sleepy. This probably happens because cytokines,chemicals our immune systems produce while fighting an infection, are powerful sleep-inducing chemicals. Sleep may help the body conserve energy and other resources that the immune system needs to mount an attack.

Sleep Problems & Mental Disorders

Sleeping problems occur in almost all people with mental disorders, including those with depression and schizophrenia. People with depression, for example, often awaken in the early hours of the morning and find themselves unable to get back to sleep. The amount of sleep a person gets also strongly influences the symptoms of mental disorders. Sleep deprivation is an effective therapy for people with certain types of depression, while it can actually cause depression in other people. Extreme sleep deprivation can lead to a seemingly psychotic state of paranoia and hallucinations in otherwise healthy people, and disrupted sleep can trigger episodes of mania (agitation and hyperactivity) in people with manic depression.
Sleeping problems are common in many other disorders as well, including Alzheimer's disease, stroke, cancer, and head injury. These sleeping problems may arise from changes in the brain regions and neurotransmitters that control sleep, or from the drugs used to control symptoms of other disorders. In patients who are hospitalized or who receive round-the-clock care, treatment schedules or hospital routines also may disrupt sleep. The old joke about a patient being awakened by a nurse so he could take a sleeping pill contains a grain of truth. Once sleeping problems develop, they can add to a person's impairment and cause confusion, frustration, or depression. Patients who are unable to sleep also notice pain more and may increase their requests for pain medication. Better management of sleeping problems in people who have other disorders could improve these patients' health and quality of life.

Sleep Disorders

At least 40 million Americans each year suffer from chronic, long-term sleep disorders each year, and an additional 20 million experience occasional sleeping problems. These disorders and the resulting sleep deprivation interfere with work, driving, and social activities. They also account for an estimated $16 billion in medical costs each year, while the indirect costs due to lost productivity and other factors are probably much greater. Doctors have described more than 70 sleep disorders, most of which can be managed effectively once they are correctly diagnosed. The most common sleep disorders include insomnia, sleep apnea, restless legs syndrome, and narcolepsy.

Insomnia

Almost everyone occasionally suffers from short-term insomnia. This problem can result from stress, jet lag and other circadian rhythm problems, diet, or many other factors. Insomnia almost always affects job performance and well-being the next day. About 60 million Americans a year have insomnia frequently or for extended periods of time, which leads to even more serious sleep deficits. Insomnia tends to increase with age and affects about 40 percent of women and 30 percent of men. It is often the major disabling symptom of an underlying medical disorder.
For short-term insomnia, doctors may prescribe sleeping pills. Most sleeping pills stop working after several weeks of nightly use, however, and long-term use can actually interfere with good sleep. Mild insomnia often can be prevented or cured by practicing good sleep habits . For more serious cases of insomnia, researchers are experimenting with light therapy and other ways to alter circadian cycles.

Sleep Apnea

Sleep apnea is a disorder of interrupted breathing during sleep. It usually occurs in association with fat buildup or loss of muscle tone with aging. These changes allow the windpipe to collapse during breathing when muscles relax during sleep. This problem, called obstructive sleep apnea, is usually associated with loud snoring (though not everyone who snores has this disorder). Sleep apnea also can occur if the neurons that control breathing malfunction during sleep.
During an episode of obstructive apnea, the person's effort to inhale air creates suction that collapses the windpipe. This blocks the air flow for 10 seconds to a minute while the sleeping person struggles to breathe. When the person's blood oxygen level falls, the brain responds by awakening the person enough to tighten the upper airway muscles and open the windpipe. The person may snort or gasp, then resume snoring. This cycle may be repeated hundreds of times a night. The frequent awakenings that sleep apnea patients experience leave them continually sleepy and may lead to personality changes such as irritability or depression. Sleep apnea also deprives the person of oxygen, which can lead to morning headaches, a loss of interest in sex, or a decline in mental functioning. It also is linked to high blood pressure, irregular heartbeats, and an increased risk of heart attacks and stroke. Patients with severe, untreated sleep apnea are two to three times more likely to have automobile accidents than the general population. In some high-risk individuals, sleep apnea may even lead to sudden death from respiratory arrest during sleep.
An estimated 18 million Americans have sleep apnea. However, few of them have had the problem diagnosed. Patients with the typical features of sleep apnea, such as loud snoring, obesity, and excessive daytime sleepiness, should be referred to a specialized sleep center that can perform a test called polysomnography. This test records the patient's brain waves, heartbeat, and breathing during an entire night. If sleep apnea is diagnosed, several treatments are available. Mild sleep apnea frequently can be overcome through weight loss or by preventing the person from sleeping on his or her back. Other people may need special devices or surgery to correct the obstruction. People with sleep apnea should never take sedatives or sleeping pills, which can prevent them from awakening enough to breathe.

Restless Legs Syndrome

Restless legs syndrome (RLS), a familial disorder causing unpleasant crawling, prickling, or tingling sensations in the legs and feet and an urge to move them for relief, is emerging as one of the most common sleep disorders, especially among older people. This disorder, which affects as many as 12 million Americans, leads to constant leg movement during the day and insomnia at night. Severe RLS is most common in elderly people, though symptoms may develop at any age. In some cases, it may be linked to other conditions such as anemia, pregnancy, or diabetes.
Many RLS patients also have a disorder known as periodic limb movement disorder or PLMD, which causes repetitive jerking movements of the limbs, especially the legs. These movements occur every 20 to 40 seconds and cause repeated awakening and severely fragmented sleep. In one study, RLS and PLMD accounted for a third of the insomnia seen in patients older than age 60.
RLS and PLMD often can be relieved by drugs that affect the neurotransmitter dopamine, suggesting that dopamine abnormalities underlie these disorders' symptoms. Learning how these disorders occur may lead to better therapies in the future.

Narcolepsy

Narcolepsy affects an estimated 250,000 Americans. People with narcolepsy have frequent "sleep attacks" at various times of the day, even if they have had a normal amount of night-time sleep. These attacks last from several seconds to more than 30 minutes. People with narcolepsy also may experience cataplexy (loss of muscle control during emotional situations), hallucinations, temporary paralysis when they awaken, and disrupted night-time sleep. These symptoms seem to be features of REM sleep that appear during waking, which suggests that narcolepsy is a disorder of sleep regulation. The symptoms of narcolepsy typically appear during adolescence, though it often takes years to obtain a correct diagnosis. The disorder (or at least a predisposition to it) is usually hereditary, but it occasionally is linked to brain damage from a head injury or neurological disease.
Once narcolepsy is diagnosed, stimulants, antidepressants, or other drugs can help control the symptoms and prevent the embarrassing and dangerous effects of falling asleep at improper times. Naps at certain times of the day also may reduce the excessive daytime sleepiness.
In 1999, a research team working with canine models identified a gene that causes narcolepsy-a breakthrough that brings a cure for this disabling condition within reach. The gene, hypocretin receptor 2, codes for a protein that allows brain cells to receive instructions from other cells. The defective versions of the gene encode proteins that cannot recognize these messages, perhaps cutting the cells off from messages that promote wakefulness. The researchers know that the same gene exists in humans, and they are currently searching for defective versions in people with narcolepsy.
Modified and reprinted courtesy of the NINDS and NIH

The Future of Sleep Science

Sleep research is expanding and attracting more and more attention from scientists. Researchers now know that sleep is an active and dynamic state that greatly influences our waking hours, and they realize that we must understand sleep to fully understand the brain. Innovative techniques, such as brain imaging, can now help researchers understand how different brain regions function during sleep and how different activities and disorders affect sleep. Understanding the factors that affect sleep in health and disease also may lead to revolutionary new therapies for sleep disorders and to ways of overcoming jet lag and the problems associated with shift work. We can expect these and many other benefits from research that will allow us to truly understand sleep's impact on our lives and apply them as new tips for getting a good night's sleep are discovered

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What Is Sleep? Latest Research & Treatments | American Sleep Assoc

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Until the 1950s, most people thought of sleep as a passive, dormant part of our daily lives. We now know that our brains are very active during sleep. Moreover, sleep affects our daily functioning and our physical and mental health in many ways that we are just beginning to understand.

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What Is Fatigue?

Fatigue is a lingering tiredness that is constant and limiting. With fatigue, you have unexplained, persistent, and relapsing exhaustion. It's similar to how you feel when you have the flu or have missed a lot of sleep. If you have chronic fatigue,, or systemic exertion intolerance disease (SEID), you may wake in the morning feeling as though you've not slept. Or you may be unable to function at work or be productive at home. You may be too exhausted even to manage your daily affairs.

In most cases, there's a reason for the fatigue. It might be allergic rhinitis, anemia, depression, fibromyalgia, or some other health condition. If that's the case, then the long-term outlook is good. WebMD looks at some common causes of fatigue and how they are resolved.

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Allergies, Hay Fever, and Fatigue

Symptoms: Fatigue, headache, itchiness, nasal congestion, and drainage

Allergic rhinitis is a common cause of chronic fatigue. But allergic rhinitis often can be easily treated and self-managed. To make a diagnosis, your doctor will assess your symptoms. The doctor will also determine through a detailed history or testing whether your allergies are triggered by pollens, insects ( dust mites or cockroaches), animal dander, molds and mildew, weather changes, or something else.

One way to reduce symptoms of allergic rhinitis -- including fatigue -- is to take steps to avoid the offending allergen. In addition, proper medication can help with symptoms. Drugs that might help include:

topical nasal steroids (recommended)

non-drowsy, second generationa oral antihistamines

topical nasal antihistamines

leukotriene modifiers

mast cell stabilizers

Allergy shots -- immunotherapy -- may help in severe cases. This treatment involves weekly shots of increasingly higher solutions of the offending allergens. Allergy shots take time to be effective and are usually administered over a period of three to five years.

Anemia and Fatigue

Symptoms: Fatigue, dizziness, feeling cold, irritability

Anemia, a condition in which your don't have enough red blood cells. It can be due to blood loss or decreased production of red blood cells. It can also be the result of hemorrhoids or GI problems such as ulcers, or cancer. Nonsteroidal anti-inflammatory drugs ( NSAIDs) such as ibuprofen or aspirin can also lead to GI problems and bleeding. Other causes of anemia include a deficiency of iron, folic acid, or vitamin B12. Chronic diseases such as diabetes or kidney disease can also cause anemia.

Continued

Depression, Anxiety, and Fatigue

Symptoms: Sadness, feeling hopeless, worthless, and helpless, fatigue

Women can get postpartum depression after the birth of a baby. Some people get seasonal affective disorder in the winter, with feelings of fatigue and sadness. Major depression is also one part of bipolar disorder.

With depression, you might be in a depressed mood most of the day. You may have little interest in normal activities. Along with feelings of fatigue, you may eat too much or too little, over- or under- sleep, feel hopeless and worthless, and have other serious symptoms.

Anxiety symptoms may include:

agitation

difficulty sleeping

excessive worrying

feeling "on alert" most of the time

feeling of impending doom

nervousness

Although the specific causes of depression and/or anxiety are unclear, these are highly treatable medical problems. Medication, psychotherapy, or a combination of the two can help relieve symptoms.

Fibromyalgia and Fatigue

Symptoms: Chronic fatigue, deep muscle pain, painful tender points, sleep problems, anxiety, depression

Fibromyalgia is one of the more common causes of chronic fatigue and musculoskeletal pain, especially in women. Fibromyalgia and chronic fatigue syndrome are considered separate but related disorders. They share a common symptom -- severe fatigue that greatly interferes with people's lives.

With fibromyalgia, you may feel that no matter how long you sleep, it's never restful. And you may feel as if you are always fatigued during daytime hours. Your sleep may be interrupted by frequent waking. Yet, you may not remember any sleep disruptions the next day. Some people with fibromyalgia live in a constant 'fibro fog' -- a hazy, mental feeling that makes it difficult to concentrate.

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Constant daytime fatigue with fibromyalgia often results in diminished exercise. That causes a decline in physical fitness. It can also cause mood-related problems. The best way to offset these effects is to try to exercise more. Exercise has a tremendous beneficial effect on sleep, mood, and fatigue.

If you do try swimming (or any moderate exercise) to ease fatigue, start slowly. As you become accustomed to the added physical activity, you can increase your time in the pool or gym. Set up a regular time for exercise, but watch overdoing it to avoid added fatigue.

Food Allergies, Food Intolerance, and Fatigue

Symptoms: Fatigue, sleepy, continually exhausted

Although food is supposed to give you energy, new medical research suggests that hidden food intolerances -- or allergies -- can do the opposite. In fact, fatigue may be an early warning sign of food intolerance or food allergy.

Ask your doctor about the elimination diet. This is a diet in which you cut out certain foods that cause a variety of symptoms, including sleepiness within 10 to 30 minutes of eating them. You can also talk to your doctor about a food allergy test -- or invest in a home test such as ALCAT -- which may help you identify the offending foods.

Heart Disease and Fatigue

Symptoms: Fatigue with an activity that should be easy

Rheumatoid Arthritis and Fatigue

Symptoms: Fatigue, morning stiffness, joint pain, inflamed joints

Rheumatoid arthritis (RA), a type of inflammatory arthritis, is another cause of excessive fatigue. Because joint damage can result in disability, early and aggressive treatment is the best approach for rheumatoid arthritis.

Medications that may be used early in mild RA include:

nonsteroidal anti-inflammatory drugs (NSAIDs)

disease-modifying antirheumatic drugs (DMARDs)

Other drugs used in more serious forms of RA include the anti-cytokine therapies (anti-tumor necrosis factor alpha agents), as well as injections and other forms of treatment.

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Sleep Apnea and Fatigue

Symptoms: Chronic fatigue, feeling exhausted upon awakening, snoring

According to the National Sleep Foundation, more than one-third of adults in the U.S. snore at least a few nights a week. If snoring is associated with periods when breathing stops, a condition called sleep apnea, a person may have daytime sleepiness and excessive fatigue.

Obstructive sleep apnea results in low oxygen levels in the blood. That's because blockages prevent air from getting to the lungs. The low oxygen levels also affect your heart and brain function. Sometimes, the only clue that you might have sleep apnea is chronic fatigue.

Talk with your doctor about a sleep study (polysomnogram) to determine if you have sleep apnea. Lose weight if you are overweight, and if you smoke, stop. Both obesity and smoking are risk factors for sleep apnea. Sleeping on your side instead of your back may help eliminate mild sleep apnea.

Type 2 Diabetes and Fatigue

Symptoms: Extreme fatigue, increased thirst and hunger, increased urination, unusual weight loss

The incidence of type 2 diabetes is escalating in children and adults in the U.S. If you have symptoms of type 2 diabetes, call your doctor and ask to be tested. While finding out you have diabetes may be frightening, type 2 diabetes can be self-managed with guidance from your doctor.

Treatment for type 2 diabetes may include:

losing excess weight

increasing physical activity

maintaining strict blood glucose control

taking diabetes medications (insulin or other drugs)

eating a low glycemic index carbohydrate diet, or, though controversial, a low-carbohydrate diet

Underactive Thyroid (Hypothyroidism) and Fatigue

Symptoms: Extreme fatigue, sluggishness, feeling run down, depression, cold intolerance, weight gain

The problem may be a slow or underactive thyroid. This is known as hypothyroidism. The thyroid is a small, butterfly-shaped gland that sits at the base of your neck. It helps set the rate of metabolism, which is the rate at which the body uses energy.

According to the American Thyroid Foundation, approximately 17% of all women will have a thyroid disorder by age 60. And most won't know it. The most common cause is an autoimmune disorder known as Hashimoto's thyroiditis. Hashimoto's stops the gland from making enough thyroid hormones for the body to work the way it should. The result is hypothyroidism, or a slow metabolism.

Blood tests known as T3 and T4 will detect thyroid hormones. If these hormones are low, synthetic hormones (medication) can bring you up to speed and you should begin to feel better fairly rapidly.

Sources

SOURCES:

American College of Rheumatology: "Rheumatoid Arthritis."

American Diabetes Association: "Type 2 Diabetes."

American Heart Association: "Women, Heart Disease, and Stroke."

National Fibromyalgia Association: "What is Fibromyalgia?"

National Institutes of Health: "Depression."

National Sleep Foundation: "Snoring...No Laughing Matter."

WomensHealth.Gov: "Hashimoto's Thyroiditis."

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Fatigue is a lingering tiredness that is constant and limiting. With fatigue, you have unexplained, persistent, and relapsing exhaustion. It's similar to how you feel when you have the flu or have missed a lot of sleep. If you have chronic fatigue,, or systemic exertion intolerance disease (SEID), you may wake in the morning feeling as though you've not slept.

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Problems With Your Thyroid

It's a small, butterfly-shaped gland that sits in your neck. It makes a hormone that helps control how you use energy. When your thyroid gland is out of whack, you're out of whack.

"People with an underactive thyroid are going to feel tired," Friedman says. "Their cells aren't working well, they're sluggish, and their reflexes are slow."

Your doctor may test your blood for thyroid hormone to see if it's to blame for your fatigue.

Heart Disease

Extreme tiredness is a common symptom of congestive heart failure, which happens when it doesn't pump as well as it should. If you have it, your fatigue usually gets worse when you exercise. You might also have swelling in your arms or legs and shortness of breath.

Sleep Apnea

This disorder keeps you from getting enough oxygen when you sleep, which means you won't get real rest during the night.

"The brain notices you're not getting rid of your CO2, and it wakes up really briefly in an alarmed state," says Lisa Shives, MD, director of the Sleep Medicine Center at the University of California, San Diego School of Medicine. You don't even realize it, which makes it hard to figure out why you're so sleepy during the day.

"You don't get into REM -- the sleep that makes you feel best," Shives says.

A device called a continuous positive airway pressure ( CPAP) machine can help keep your airways open for a solid night's sleep.

Menopause

If you're a woman who's going through menopause, you may find it hard to get good sleep. Your hormones change a lot at this time, which give you night sweats and hot flashes. That can keep you up at night and leave you dragging during the day.

Depression

It robs your brain of the chemicals it needs to work at its best. One of those is serotonin, which helps regulate your internal body clock.

Depression can lower your energy levels and make you feel tired during the day. You may also find it hard to fall asleep at night, or you might wake up earlier than you want in the morning.

Talk to you doctor if you think you're depressed. Talk therapy and medicine can help.

Sources

SOURCES:

Theodore Friedman, MD, PhD, chair of medicine and chief of division of endocrinology, molecular medicine and metabolism, Charles R. Drew University of Medicine and Science, Los Angeles.

National Sleep Foundation: "How Much Sleep Do We Really Need?"

Lisa Shives, MD, director, Sleep Medicine Center, University of California at San Diego School of Medicine.

American Society of Hematology: "Anemia."

American Thyroid Association: "Thyroid Information."

Fritschi, C. Journal of Psychosomatic Research, 2011.

University of Maryland Medical Center: "Diabetes."

Margaret Wehrenberg, PsyD, clinical psychologist, Naperville, IL.

National Heart, Lung, and Blood Institute: "What are Signs and Symptoms of Heart Disease?"

National Institute on Aging: "Menopause: Time for a Change."

NHS: "10 medical reasons for feeling tired."

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Why Am I So Tired? Conditions That Cause Fatigue

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It's a small, butterfly-shaped gland that sits in your neck. It makes a hormone that helps control how you use energy. When your thyroid gland is out of whack, you're out of whack. "People with an underactive thyroid are going to feel tired," Friedman says.