Sleeping Disorders

During the earliest phases of sleep, you are still relatively awake and alert. The brain produces what are known as beta waves, which are small and fast. As the brain begins to relax and slow down, slower waves known as alpha waves are produced. During this time when you are not quite asleep, you may experience strange and extremely vivid sensations known as hypnagogic hallucinations. Common examples of this phenomenon include feeling like you are falling or hearing someone call your name

Stage 1

is the beginning of the sleep cycle, and is a relatively light stage of sleep. Stage 1 can be considered a transition period between wakefulness and sleep. In Stage 1, the brain produces high amplitude theta waves, which are very slow brain waves. This period of sleep lasts only a brief time (around 5-10 minutes). If you awaken someone in the stage, they might report that they weren't really asleep.

Stage 2

Stage 2 is the second stage of sleep and lasts for approximately 20 minutes. The brain begins to produce bursts of rapid, rhythmic brain wave activity known as sleep spindles. Body temperature starts to decrease and heart rate begins to slow.

Stage 3

Deep, slow brain waves known as delta waves begin to emerge during stage 3 sleep. Stage 3 is a transitional period between light sleep and a very deep sleep.

Stage 4

Stage 4 is sometimes referred to as delta sleep because of the slow brain waves known as delta waves that occur during this time. Stage 4 is a deep sleep that lasts for approximately 30 minutes. Bed-wetting and sleepwalking usually occur at the end of stage 4 sleep.

Stage 5

Most dreaming occurs during the fifth stage of sleep, known as rapid eye movement (REM) sleep. REM sleep is characterized by eye movement, increased respiration rate, increased brain

activity. REM sleep is also referred to as paradoxical sleep because while the brain and other body systems become more active muscles become more relaxed. Dreaming occurs due because of increased brain activity, but voluntary muscles become paralyzed.

Sleep does not progress through these stages in sequence, however. Sleep begins in stage 1 and progresses into stages 2, 3 and 4. After stage 4 sleep, stage 3 and then stage 2 sleep are repeated before entering REM sleep. Once REM sleep is over, the body usually returns to stage 2 sleep. Sleep cycles through these stages approximately 4 or 5 times throughout the night.

On average, we enter the REM stage approximately 90 minutes after falling asleep. The first cycle of REM sleep might last only a short amount of time, but each cycle becomes longer, so REM sleep can last up to an hour as sleep progresses

The most common sleep disorders include:

• Bruxism: The sufferer involentarily grinds his or her teeth while sleeping

• Delayed sleep phase syndrome (DSPS): a sleep disorder of circadian rhythm

• Insomnia: Inability to fall asleep at will or at normal times

• Jet lag or desynchronosis: Temporary condition resulting in out of sync sleep patterns as a result of rapidly travelling across multiple time zones

• Narcolepsy: The condition of falling asleep spontaneously and unwillfully

• Night terror or Pavor nocturnus or sleep terror disorder: abrupt awakening from sleep with behavior consistent with terror

• Parasomnias: Include a variety of disruptive sleep-related events

• Periodic limb movement disorder (PLMD): Involuntary movement of arms and/or legs during sleep

• Rapid eye movement behavior disorder (RBD): Acting out violent or dramatic dreams while in REM sleep

• Restless leg syndrome (RLS): An irresistible urge to move legs while sleeping. Often accompanies PLMD.

• Sleep apnea: The obstruction of the airway during sleep

• Sleep paralysis: Conscious paralysis upon waking or falling asleep

• Sleepwalking or somnambulism: Engaging in activities that are normally associated with wakefulness (such as eating or dressing), which may include walking, without the conscious knowledge of the subject

• Snoring: Loud breathing patterns while sleeping, sometimes accompanying sleep apnea

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