Can't sleep? You're not alone! At least one in four Americans spends time tossing and turning on a regular basis. Insomnia is certainly not rare. In fact, there are upwards of 85 recognized sleep disorders affecting more than 70 million Americans! Let's look at some common sleep-zappers. The most basic sleep disorder is called insomnia. People with insomnia just don't get enough sleep at night, either due to difficulty falling asleep, frequent nightly awakenings or early morning rising. Insomnia can be acute, meaning that it lasts for less than a month, or chronic, lasting for a month or longer. Acute insomnia can result from periods of stress, illness or physical discomfort. Some medications can cause temporary insomnia, as can environmental factors, like a new location, bright light or excess noise. Chronic insomnia, meanwhile, is more often related to depression, anxiety or unremitting stress. Another common sleep difficulty, a circadian rhythm disorder, results from disruptions to the body's internal clock, or 24-hour sleep cycle. This "clock" is actually a small part of the brain called the suprachiasmatic nucleus of the hypothalamus, which rests above the nerves leaving the back of the eyes. Common causes of circadian rhythm disorders include jet lag and working odd hours. That's because unusual exposure to light and exercise can effectively "reset" the body's clock, moving it forward or backward and making sleep difficult. Snoring is present in up to 45 percent of Americans, and can present problems when the noise is so loud that it awakens the sleeper. This rattling sound is produced when the air you inhale passes over the throat's relaxed tissue. Sometimes, snoring can point to a more serious problem known as sleep apnea, which occurs when the upper airway becomes blocked, interrupting breathing for brief periods during the night. People with sleep apnea are often overweight, or may have particularly small inner throats. In addition, sleep apnea often occurs in people with enlarged tonsils. Restless leg syndrome is a condition where a person experiences severe discomfort in their legs and feet, which can often only be eased by walking around. Because this syndrom peaks during the night, it can cause hours of sleep lost to restless pacing. Sometimes, restless leg sufferers experience erratic leg movements during sleep, which can disturb the body's sleep cycles. Sleepwalking is a disorder that occurs during non-REM sleep. Sleepwalkers can perform any range of activities while they aren't awake, such as turning on the TV or making a sandwich, yet they will often not remember the nocturnal events the next day. Another sleep stealer is narcolepsy, a brain disorder that causes daytime sleepiness. People with narcolepsy experience constant tiredness during the day and often find long naps refreshing. On rare occasions, narcolepsy can result in brief "sleep attacks" where sufferers fall asleep in the middle of the day while going about their normal business. Restorative sleep is vitally important, so if you are experiencing signs of a sleep disorder, please see your doctor to discuss treatment options.