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Sleep: Understanding the Basics

Sleep (n)

a. A natural periodic state of rest for the mind and body, in which the eyes usually close and consciousness is completely or partially lost, so that there is a decrease in bodily movement and responsiveness to external stimuli. During sleep the brain in humans and other mammals undergoes a characteristic cycle of brain-wave activity that includes intervals of dreaming.

b. A period of this form of rest.

c. A state of inactivity resembling or suggesting sleep; unconsciousness, dormancy, hibernation, or death.

Birds do it, bees do it, and, human certainly do it. Sleep that is. Science has always thought sleep to be a passive state but research are now unraveling more than what we have known about sleep. For instance, sleep to be a dynamic process where our brains are active during sleep. In short, there is more to sleep than shutting the eyes.


Sleep is a necessary and vital biological function. It is essential to a person’s physical and emotional well being. Studies have shown that without enough sleep, a person’s ability to perform even simple tasks declines dramatically.


Even though we spend roughly one-third of life asleep, researchers still do not know why, and this question has baffled scientists for centuries. Until now no one is really sure. Some believe that sleep gives the body a chance to recuperate from the day’s activities but in reality, the amount of energy saved by sleeping for even eight hours is miniscule – about 50 kCal.

Researchers however have shortlisted a few basic theories:

  • Sleep enables the body and mind to rejuvenate, reenergise, and restore. As a person sleeps, it is thought that the brain performs vital housekeeping tasks, such as organising long-term memory, integrating new information, repairing and renewing tissue, nerve cells and other biochemicals. Sleep allows the body to rest and the mind to sort out past, present, and future activities and feelings.
  • The amount and quality of sleep achieved is directly proportional to the amount and quality of the next day’s productivity.
  • A role in learning either helping to form new connections between brain cells or pruning unnecessary ones.
  • Reversing damage from oxidative stresses incurred while awake.
  • Promoting longevity.


A major reason why humans sleep is due to circadian rhythms, also known as the biological clock. A cycle that lasts 24 hours is called circadian. Some physiological functions that are circadian include body temperature and certain hormone secretions. So too, humans have a natural cycle of approximately the length of one day.

Small structures in the brain called suprachiasmatic nuclei (SCN) coordinate circadian rhythms. The SCN, in turn, is very sensitive to the presence or absence of light. This may explain why daytime sleep has been found to be less restful than nighttime sleep.

Sleep and wakefulness alternate, usually between night and day, respectively. For most people, sleepy peaks occur every 12 hours, at night, and around mid-afternoon. Through a complex process of hormonal and neurological changes, daylight naturally triggers periods of wakefulness. Studies have shown, however, that the absence of light does not disable our biological clocks.

Normal peaks of alertness occur during daylight hours. The mid-afternoon dip, called a postprandial dip (after lunch), is caused by a natural decrease in body temperature. When our body temperature begins to drop, we are sleepier than when it begins to rise.


There are five phases of sleep: stages 1, 2, 3, 4 and REM (Rapid Eye Movement). Usually when you are sleeping, you begin at stage 1 and go through each stage until you reach REM sleep, and then you begin the cycle again. Each complete sleep cycle takes from 90 to 110 minutes. Your brain acts differently in each stage of sleep.


Stage 1: Light Sleep

During the first stage of sleep, we’re half awake and half asleep. Our muscle activity slows down and slight twitching may occur. This is a period of light sleep, meaning we can be awakened easily at this stage.

Stage 2: True Sleep

Within ten minutes of light sleep, we enter stage two, which lasts around 20 minutes. The breathing pattern and heart rate start to slow down. This period accounts for the largest part of human sleep.

Stages 3 and 4: Deep Sleep

During stage three, the brain begins to produce delta waves, a type of wave that is large (high amplitude) and slow (low frequency). Breathing and heart rate are at their lowest levels.

Stage four is characterised by rhythmic breathing and limited muscle activity. If we are awakened during deep sleep we do not adjust immediately and often feel groggy and disoriented for several minutes after waking up. Some children experience bed-wetting, night terrors, or sleepwalking during this stage.


The first rapid eye movement (REM) period usually begins about 70 to 90 minutes after we fall asleep. We have around three to five REM episodes a night. Although we are not conscious, the brain is very active – often more so than when we are awake. This is the period when most dreams occur. Our eyes dart around (hence the name), our breathing rate and blood pressure rise. However, our bodies are effectively paralysed, said to be nature’s way of preventing us from acting out our dreams. After REM sleep, the whole cycle begins again.


There is no set amount of time that everyone needs to sleep, since it varies from person to person. Some people are naturally short or long sleepers. Thomas Edison, Martha Stewart, and Jay Leno have remarked that they sleep less than five hours a night. In contrast, Albert Einstein and Calvin Coolidge claimed they needed ten or more hours per night. Other well-known people such as Ronald Reagan and Winston Churchill took naps throughout the day.

Research indicates that people like to sleep anywhere between 5 and 11 hours, with the average being 7.75 hours.

The easiest way to find out how much sleep you need is this simple answer – “The amount of sleep we require is what we need not to be sleepy in the daytime.”

Some experts suggest that the best way to determine personal sleep requirements is by waking up without an alarm clock. The amount of time spent sleeping would be the personal requirement. Other experts suggest that an ideal amount of sleep is the amount needed to feel refreshed and well rested in the morning and alert all day. Contrary to popular belief, the amount of sleep a person needs does not decrease with age.


We are always on the go, around-the-clock society, moving rapidly from one task to another at rapid speed. We even have a name for it – multitasking. But until a tragedy like illness strikes, we often ignore the importance of sleep.

Current finding says that we are a sleep deprived society. This may be attributed to longer work hours and increased commute times. Many findings have proved that sleep deprivation have been linked to many tragedies to human errors due to lack of sleep.

Some historic examples of severe sleep deprivation include the Exxon Valdez oil spill, the NASA Challenger shuttle explosion, and the Chernobyl nuclear accident. The most common consequence of lost sleep has become a public health issue – sleeping behind the wheel. One third of all drivers will fall asleep while driving at least once in their lifetime.

The average sleep-deprived individual may experience impaired performance, irritability, lack of concentration, and daytime drowsiness. They are less alert, attentive, and unable to concentrate effectively. Additionally, because sleep is linked to restorative processes in the immune system, sleep deprivation in a normal adult causes a biological response similar to the body fighting off an infection.


Ask yourself the following questions:

  • Do you often feel drowsy during the day?
  • Do you usually fall asleep within the first five minutes after lying down in bed?
  • Need an alarm clock in order to wake up on time.
  • Have a hard time getting out of bed in the morning.
  • Feel sluggish in the afternoon.
  • Get sleepy in meetings, lectures, or warm rooms.
  • Get drowsy after heavy meals or when driving.
  • Need to nap to get through the day.
  • Fall asleep while watching TV or relaxing in the evening.
  • Feel the need to sleep in on weekends.

If you answered yes to any of them, you’re likely to be sleep deprived or have a sleep disorder. There are many different types of sleep disorders. Examples include:

• Insomnia,

• Sleep-related breathing disorders such as sleep apnea,

• Periodic limb movement disorder,

• Sleepwalking, and

• Restless legs syndrome.

Other than daytime drowsiness and rapidly falling asleep at night, short episodes called microsleeps are another hallmark of sleep deprivation. Microsleeps are short bursts of sleep that occur during the waking hours. These may be so transient that you may not even be aware that they are occurring.


Here are some of the most common sleep disorders that can keep us awake at night:


Snoring is not only an embarrassment for sufferers but a test of endurance for family and friends. Snoring occurs when the soft palate tissue at the back of the throat relaxes too much, obstructing the entrance to the throat. As air tries to pass through, the soft palate vibrates and produces the snoring sound. The problem may get worse with age but one of the main causes is being overweight.

Sleep apnea

Sleep apnea owes its meaning to the Greek word apnea, meaning ‘want of breath’. Sleep apnea (AP-ne-ah) is a common disorder in which you have one or more pauses in breathing or shallow breaths while you sleep. Breathing pauses can last from a few seconds to minutes. They often occur 5 to 30 times or more an hour. Typically, normal breathing then starts again, sometimes with a loud snort or choking sound. Sleep apnea is one of the leading causes of excessive daytime sleepiness.


Insomnia is a prolonged and usually abnormal inability to obtain adequate, uninterrupted sleep. Symptoms may include having trouble falling asleep, staying asleep or waking up too early in the morning, feeling unrefreshed. The consequences are unpleasant, leaving sufferers feeling exhausted, irritable and unable to concentrate on simple tasks. There’s no one specific trigger for insomnia but certain conditions seem to make individuals more likely to experience – people aged over sixty, females, those with a history of depression, and those who are highly stressed.

Restless Leg Syndrome (RLS)

Restless leg syndrome causes a tingling, itching sensation and unexplained aches and pains in the lower limbs. Sleep is disturbed because people often have a strong urge to move the legs to relieve the discomfort by stretching, rubbing the legs or getting up and pacing around. RLS may be inherited. It occurs three to five times more frequently in first-degree relatives of RLS sufferers. Hormonal changes during pregnancy may worsen the symptoms. Other cases of RLS are associated with iron deficiency or nerve damage in the legs.


The habit of grinding, gnashing, grating, or clenching the teeth is termed bruxism. While its exact cause is unknown, most experts believe that bruxism can occur as a response to increased psychological stress. Bruxism involves any type of forceful contact between the teeth, whether silent and clenching, or loud and grating. Certain sleep disorders are accompanied by bruxism like drinking alcohol and taking certain medications (for example, antidepressants) may worsen the bruxism. Some studies show that persons whose personalities may be described as compulsive, controlling, precise, or aggressive have an increased incidence of bruxism.



The effects of the root of valerian (Valeriana officinalis) on sleep have been examined in people with sleep problems. Some studies have suggested that valerian helps with the onset of sleep and with sleep maintenance. Chamomile is another commonly used herb for the treatment of insomnia. The FDA considers chamomile to be safe and the herb has no known adverse effects.


Melatonin is a hormone that is synthesised by the pineal gland in humans and produced in animals as well as plants. Although the effects of melatonin are complex and poorly understood, it plays a critical role in the regulation of sleep-wake cycle and other circadian rhythms. Melatonin has been studied as a possible treatment of circadian rhythm disorders and may be helpful in decreasing sleep disturbances caused by jet lag.


Acupuncture is often used in Traditional Chinese Medicine for the treatment of insomnia. This procedure involves the insertion of very fine needles (sometimes in combination with electrical stimulus or with heat produced by burning specific herbs) into the skin at specific acupuncture points in order to influence the functioning of the body.

Relaxation and Meditation

Increased muscle tension and intrusive thoughts interfere with sleep. Therefore, it is not surprising that techniques aimed at relaxing muscles (progressive muscle relaxation and biofeedback) and quieting the mind (meditation) have been found to be effective treatments for insomnia. Several studies show that regular meditation practice, either alone or as a part of yoga practice, results in higher blood levels of melatonin, an important regulator of sleep.


Cut out caffeine

Caffeine can have a pronounced effect on sleep, causing insomnia and restlessness. In addition to coffee, tea, and soft drinks, look for hidden sources of caffeine such as chocolate, cough and cold medicine, and other over-the-counter medicine.

Avoid sweets

Although sugar can give a burst of energy, it’s short-lived and can cause uneven blood sugar levels. This can disrupt sleep in the middle of the night as blood sugar levels fall.

Eat foods that help you sleep

Tryptophan is an amino acid that is a precursor to serotonin, which is then converted to melatonin. Carbohydrate snacks such whole grain crackers before bedtime may help to promote sleep. Just be sure to stay away from sweets.

Eat magnesium-rich foods

Magnesium is a natural sedative. Deficiency of magnesium can result in difficulty sleeping, constipation, muscle tremors or cramps, anxiety, irritability, and pain. It has also been use for people with restless leg syndrome. Foods rich in magnesium are legumes and seeds, dark leafy green vegetables, wheat bran, almonds, cashews, blackstrap molasses, brewer’s yeast, and whole grains.


  • Work, household responsibilities and child care can make sleep difficult to come by. Stress and worries can affect the quality of a good night’s sleep. If you’re having trouble sleeping, try changing your sleep habits for a better night’s rest with these tips:
  • Go to bed and get up at about the same time every day, even on the weekends. Sticking to a schedule helps reinforce your body’s sleep-wake cycle and can help you fall asleep more easily at night.
  • Don’t eat or drink large amounts before bedtime. Eat a light dinner at least two hours before sleeping. If you’re prone to heartburn, avoid spicy or fatty foods, which can make your heartburn flare and prevent a restful sleep. Also, limit how much you drink before bed. Too much liquid can cause you to wake up repeatedly during the night for trips to the toilet.
  • Avoid nicotine, caffeine and alcohol in the evening. These are stimulants that can keep you awake. Smokers often experience withdrawal symptoms at night, and smoking in bed is dangerous. Avoid caffeine for eight hours before your planned bedtime. Your body doesn’t store caffeine, but it takes many hours to eliminate the stimulant and its effects. And although often believed to be a sedative, alcohol actually disrupts sleep.
  • Exercise regularly. Regular physical activity, especially aerobic exercise, can help you fall asleep faster and make your sleep more restful. However, for some people, exercising right before bed may make getting to sleep more difficult.
  • Make your bedroom cool, dark, quiet and comfortable. Create a room that’s ideal for sleeping. Adjust the lighting, temperature, humidity and noise level to your preferences. Use blackout curtains, eye covers, earplugs, extra blankets, a fan or white-noise generator, a humidifier or other devices to create an environment that suits your needs.
  • Sleep primarily at night. Daytime naps may steal hours from nighttime slumber. Limit daytime sleep to about a half-hour and make it during midafternoon. If you work nights, keep your window coverings closed so that sunlight, which adjusts the body’s internal clock, doesn’t interrupt your sleep. If you have a day job and sleep at night, but still have trouble waking up, leave the window coverings open and let the sunlight help awaken you.
  • Choose a comfortable mattress and pillow. Features of a good bed are subjective and differ for each person. But make sure you have a bed that’s comfortable. If you share your bed, make sure there’s enough room for two. Children and pets are often disruptive, so you may need to set limits on how often they sleep in bed with you.
  • Start a relaxing bedtime routine. Do the same things each night to tell your body it’s time to wind down. This may include taking a warm bath or shower, reading a book, or listening to soothing music. Relaxing activities done with lowered lights can help ease the transition between wakefulness and sleepiness.
  • Go to bed when you’re tired and turn out the lights. If you don’t fall asleep within 15 to 20 minutes, get up and do something else. Go back to bed when you’re tired.
  • Don’t agonise over falling asleep. The stress will only prevent sleep.

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