Understanding Sleep Problems -- The Basics
During normal sleep, you cyclethrough REM and four stages ofnon-REM (NREM) sleepnumerous times a night. Stage 1of NREM sleep is the lightest,while stage 4 is the deepest.
When you're repeatedlyinterrupted and can't cycle normally through these types and stages ofsleep, you may feel tired, fatigued, and have trouble concentrating andpaying attention while you're awake. Sleepiness puts you at greater riskfor car wrecks and other accidents.
What Are Sleep Disorders?
Circadian Rhythm Disorders
Typically, people sleep at night -- thanks not only to the conventions ofthe 9-to-5 workday, but also to the close interaction between our naturalsleep and alertness rhythms, which are driven by an internal "clock."
This clock is a small part of the brain called the suprachiasmatic nucleusof the hypothalamus. It sits just above the nerves leaving the back of oureyes. Light and exercise "reset" the clock and can move it forward orbackward. Abnormalities related to this clock are called circadian rhythmdisorders ("circa" means "about," and "dies" means "day").
Circadian rhythm disorders include jet lag, adjustments to shift work,delayed sleep phase syndrome (you fall asleep and wake up too late), andadvanced sleep phase syndrome (you fall asleep and wake up too early).
People who have insomnia don't feel as if they get enough sleep at night.They may have trouble falling asleep or may wake up frequently duringthe night or early in the morning. Insomnia is a problem if it affectsyour daytime activities. Insomnia has many possible causes, includingstress, anxiety, depression, poor sleep habits, circadian rhythm disorders(such as jet lag), and taking certain medications.
Many adults snore. The noise is produced when the air you inhale rattlesover the relaxed tissues of the throat. Snoring can be a problem simplybecause of the noise it causes. It may also be a marker of a more serioussleep problem called sleep apnea.
Sleep apnea occurs when the upper airway becomes completely orpartially blocked, interrupting regular breathing for short periods of time -- which then wakes you up. It can cause severe daytime sleepiness. If leftuntreated, severe sleep apnea may be associated with high bloodpressure and the risk of stroke and heart attack.