Sleep is characterized by two different types of activities: slow wave sleep (SWS) and rapid eye movement (REM) sleep.
Sleep begins in the SWS phase, lasting for most of the night, while REM sleep occurs periodically. Although REM is less restful than SWS, it is essential to good health. Sleep is an active process, involving interactions and exchanges of chemical messages to orchestrate sleep patterns. Although the exact function of these messages is unknown, alcohol consumption is known to affect the messengers that influence sleep.
Alcohol consumption can induce sleep disorders that disrupt the alternating states of sleep, in turn leading to sleep disturbances. While alcohol produces a sedating effect that does decrease the amount of time required to fall asleep, it actually negatively affects the quality of sleep, leading to fatigue and drowsiness. When a large amount of alcohol is consumed close to bedtime, an individual may skip the first stage of sleep, entering a deep sleep immediately. As alcohol wears off, the body leaves the deep sleep phase and returns to REM sleep which is much easier to wake up from. Over the course of a night, a non-drinking individual may experience six or seven cycles of REM sleep, while an individual who has consumed alcohol before bed may only experience one or two, leaving him/her with a feeling of exhaustion upon waking.
Drinking a lot of alcohol may also make an individual get up frequently throughout the night to use the bathroom. As alcohol is a diuretic, the body loses extra fluid through sweating as well, often leaving an individual dehydrated. Drinking may also make an individual snore loudly because it relaxes muscles in the body. This can cause the throat, mouth and nose to stop air from flowing smoothly, resulting in vibrations and a narrowing of the airway. Alcohol may cause sleep apnea, a disorder in which the upper air passage narrows or closes during sleep. This results in interrupted breathing, waking an individual so that they may return to normal breathing and fall asleep again. Apnea can occur countless times during the night, greatly contributing to daytime sleepiness. Those who rely on alcohol to fall asleep are also at an increased risk of experiencing sleepwalking, sleep talking and memory problems.
Compared to moderate drinking, alcoholism can produce different side effects such as increased time required to fall asleep, frequent sleep disturbances and decreased sleep quality. Any abrupt reduction in alcohol consumption may lead to an onset of withdrawal symptoms and insomnia. Those who experience hallucinations during withdrawal from alcohol may do so because of sleep being in almost exclusive periods of REM interrupted by sleep disturbances.
Lack of quality sleep can cause many health problems and put individuals at an increased risk for accidents. Lack of sleep has been linked to increased risk for depressive disorders, heart disease and impaired breathing. Additionally, excessive sleepiness due to lack of quality sleep can put individuals at risk for impaired social and occupational function, memory deficits and car crashes.
Despite improvement in sleep patterns after withdrawal symptoms subside, those with alcoholism may never return to normal sleep patterns, even with years of abstinence. They will continue to experience poor sleep with decreased SWS and increased wakefulness at night, leading to fatigue. This effect may produce a false belief that resuming drinking will provide restful sleep, making it one of the major contributors to relapse in alcoholics.
Rather than using alcohol as a means of inducing drowsiness, there are a number of ways to produce a good night’s sleep. Engaging in exercise, organizing thoughts before bed and staying away from caffeine or alcohol in the late evening are effective ways to achieve a sound sleep. Creating better sleep habits, such as regular wake and bed times, can also improve sleep quality and daytime functioning.