Alcohol – Myths and Facts
One of the most common sleep myths is the effects of alcohol and its relaxing qualities. The correlations between drinking and sleeping can be hard to understand, as it is true that having a nightcap makes it easier to fall asleep. However, there is a darker side to this seemingly harmless habit.
Alcohol Interrupts Your Sleep
Alcohol is a relaxing substance that cripples your nervous system. Even in small doses, alcohol begins to suppress the parts of your brain that are responsible for your impulse control and behavior. It makes us more social and relaxed freeing us from our inhibitions. However, when alcohol has stayed in our bodies for longer, it starts to suppress other parts of the brain as well. We begin to feel sleepy as different functions in the brain are slowly shutting down. The effect is similar to any anesthetic, although slower and not as strong. Be as it may, falling asleep is very easy in this state.
But here is the catch: alcohol-induced sleep is hardly natural. In many ways, it resembles sleep aided by anesthesia (which is all but restorative). Alcohol also interrupts your sleep making it discontinuous especially in the early morning hours. Often these nightly awakenings are brief and might go totally unnoticed. That is why it can be sometimes difficult to see the connection between daytime tiredness and that nightcap you enjoyed the night before. Even half a glass of wine can be enough to disrupt your sleep.
Alcohol Suppresses REM Sleep
Alcohol also affects the natural balance of your sleep stages. It increases the amount of deep sleep, which might not sound that bad to you, but at the same time, it is one of the most efficient REM sleep suppressors known. REM sleep is essential for learning and establishing memories. It is also the one sleep stage during which most of the dreams take place. Therefore, not getting enough REM sleep can turn out bad for you. Studies have shown that consuming alcohol after a day of studying severely impairs your learning results. In fact, memorizing learned skills and knowledge was impaired even when there was a few days' gap between learning and the first drop of alcohol!
Alcohol can harm your sleep even in small doses, but habitual drinking is the worst. Using alcohol regularly deprives you of REM sleep every night and the effects accumulate. The damage caused by insufficient REM sleep is evident with heavy drinkers. People that have spent several nights out in a row know that the first sober night after a longer drinking spree can be very restless and is often accompanied by vivid nightmares and night sweats. These alcohol withdrawal symptoms are mostly provoked by the lack of REM sleep. The body tries to compensate for the lost REM sleep by boosting it temporarily. As a result, the dreams can get extremely lively and distressing, and sometimes even hallucinations appear. The most severe form of alcohol withdrawal is delirium tremens which can happen after prolonged alcohol abuse if drinking is suddenly stopped. It is characterized by strong and scary hallucinations, paranoia, muscle tremors, and sometimes aggressive behavior. Without medical attention, it is potentially a life-threatening condition.
Habits From This Lesson
Ebrahim, I. O., Shapiro, C. M., Williams, A. J., & Fenwick, P. B. (2013). Alcohol and sleep I: effects on normal sleep. Alcoholism: Clinical and Experimental Research, 37(4), 539-549.
Walker, M. (2017). Why we sleep: Unlocking the power of sleep and dreams. Simon and Schuster.