Is it true that drinking alcohol causes insomnia?
Alcohol is a central nervous system depressant, meaning it slows down brain function. While alcohol has sedative properties that can cause feelings of relaxation and sleepiness, it has also been linked to poor sleep quality and length, particularly when consumed in excess. Insomnia is a common symptom in people who have substance use disorders. Alcohol use has been shown in studies to exacerbate the symptoms of sleep apnea.
It's crucial to consider how alcohol affects sleep by going through the phases of the human sleep cycle.
There are four steps to a regular sleep cycle: three non-rapid eye movement (NREM) stages and one rapid eye movement (REM) stage.
⢠Stage 1 (NREM): This is the first stage, which is simply the transition from wakefulness to sleep, during which the body begins to shut down. The heart rate, breathing, and eye movements of the sleeper begin to slow down, and their muscles begin to relax. The function of the brain starts to decline as well. This stage is often referred to as light sleep.
⢠Stage 2 (NREM): As the sleeper progresses deeper into sleep, their heartbeat and breathing rates slow down. Their body temperature will drop, and their eyes will remain closed. The second stage of the sleep cycle is normally the longest of the four.
⢠Stages 3 (NREM): During this stage of the sleep cycle, heartbeat, breathing rates, and brain activity all hit their lowest levels. The muscles are completely relaxed and the eye movements have stopped. Slow-wave sleep is the name for this stage.
⢠REM sleep: REM sleep begins about 90 minutes after a person falls asleep. The sleeper's breathing rate and pulse will quicken, and his or her eye movements will resume. Dreaming is most common during REM sleep. This stage is thought to be involved in memory consolidation5 as well.
Alcohol and Insomnia
Insomnia is characterized as âa persistent difficulty7 with sleep initiation, length, consolidation, or quality,â and it is the most common sleep disorder. ⢠People who drink before bed frequently develop insomnia symptoms and feel overly tired the next day, as alcohol can decrease REM sleep and cause sleep disturbances. This can lead to a vicious cycle8, in which they self-medicate with alcohol to fall asleep, consume caffeine and other stimulants during the day to stay awake, and then use alcohol as a sedative to counteract the stimulant impact.
Conclusion:
Drinking alcohol before bed may contribute to REM sleep suppression over the first two cycles. Since alcohol is a sedative, drinkers' sleep onset is sometimes faster, and some collapse into a deep sleep rather soon. This can trigger an imbalance between slow-wave and REM sleep as the night goes on, resulting in less of the latter and more of the former. Overall sleep quality suffers, as a result, resulting in shorter sleep time and more sleep disturbances.
