In normal sleep, the body goes through two stages: REM and deep sleep. Deep sleep is when the body is able to repair damage and grow. REM sleep is when dreams occur and the brain organises memories and new experiences. Alcohol tends to lengthen deep sleep time, disrupting the time spent in REM sleep.
Although it may seem positive that the body has more time to restore itself during sleep, the sleep cycle is carefully regulated by a variety of chemicals to ensure that the body and brain are able to carry out their necessary functions during sleep. Although the role that these chemicals have in inducing sleep is not completely clear, alcohol certainly affects how well these chemicals work during sleep.
Nightcaps, Sleep and REM Rebound
Many people have a nightcap before bed as they believe that it helps them to fall sleep. Although alcohol briefly acts as a stimulant, it does then act as sedative, shortening the length of time needed to fall asleep. However, it is also able to disrupt the later stages of sleep, often causing people to wake up and cause difficulties with returning to sleep. This is known as ‘REM rebound’ and occurs in response to how the body metabolises alcohol.
During the first part of sleep, the metabolism of the body is altered because of the higher blood alcohol levels. As the body moves into a second sleep cycle, the alcohol has already been metabolised (processed and removed from the system). However, as the body adjusts its metabolism back to normal through its feedback systems, the metabolism over-corrects itself. This then causes the metabolism to adjust in the opposite direction once more, disturbing sleep. This is the REM rebound occurring and it is this that often causes fatigue the following day.
Everyone knows what the body feels like after a bad night’s sleep and if alcohol has been drunk the night before, the effects of poor sleep are magnified. Even consuming alcohol earlier in the evening, such as after work, can cause restlessness during the night. Researchers have also shown that those who are given a low dose of alcohol after a bad night’s sleep perform poorly in driving simulators.
Obstructive Sleep Apnoea, Alcoholism and Sleep
Alcohol also contributes to sleep disorders such as obstructive sleep apnoea (OSA), a condition often more common in those who drink heavily or suffer from alcoholism. Sleep apnoea occurs when breathing is obstructed during the night due to muscle relaxation in the airway. This causes many interruptions to breathing during the night, where the sufferer briefly wakes up and then returns to sleep.
Those who are alcoholic and withdraw from drinking are often unable to sleep properly, with studies showing that many abstinent alcoholics never achieve ‘normal’ sleep patterns. This may then contribute to relapses, as many perceive alcohol as essential for inducing sleep.
With many serious health problems caused by excessive alcohol consumption, few realise how much impact a nightcap can have on a good night’s sleep. Avoiding nightcaps and excessive alcohol consumption, as well as staying away from caffeine and fatty foods can help improve sleep quality. For those who suffer from sleep problems, avoiding watching TV or using the laptop in bed can also help improve sleep quality and keeping the bedroom comfortable with coordinated soft furnishings and pine bedroom furniture may also help create a comfortable environment for sleep.