The Effect of Alcohol on Sleep

How Does Alcohol Affect Sleep?

Many of us have experienced having a glass of wine or a couple of beers before bed simply because it felt relaxing and helped us fall asleep easier. For some, this is part of their nightly routine and they may not realize just how much harm it can cause.

To better understand the process, we first need to get familiar with the concept of REM sleep.

What is REM Sleep and Why Is It Important?

While we sleep, two sleep stages alternate: REM (Rapid Eye Movement) and NREM (Non-Rapid Eye Movement) sleep.

REM sleep is the phase of the sleep cycle characterized by rapid, side-to-side eye movements. This phase usually occurs during the latter half of the sleep period and is far more significant than most people realize.

Dreams & Creativity: During REM sleep, we experience our most vivid and complex dreams. Research suggests that these dreams help with problem-solving, creative thinking, and generating new ideas. It’s no coincidence that we say "sleep on it"!

Emotional Processing: REM sleep plays a crucial role in processing emotional memories and maintaining emotional health. This sleep phase aids in the emotional integration of the previous day’s experiences, supporting mental stability. Emotions also play an important role in storing and recalling memories. They can activate certain parts of memory, making it easier to access memories. For example, emotional memory springs into action when a long-forgotten scent instantly transports us back to a specific childhood event or another major period in our lives.

Memory & Learning: REM sleep plays a role in consolidating memories, especially complex, abstract, or new information. This phase helps solidify new knowledge and the acquisition of complex skills.

Brain Function & Neural Connections: During REM sleep, the brain is actively working to develop and maintain neural networks. This is particularly important for the developing brain! It’s no coincidence that in roughly the last two weeks before birth, when neural connections in the brain form at an accelerated rate, the fetus shifts from an earlier 50% REM and 50% NREM sleep ratio to nearly entirely REM sleep. Later, during infancy and early childhood, a large portion of our sleep is spent in the REM phase.

Stress Management & Mental Health: It has been observed that REM sleep deprivation is linked to stress, depression, and other mental health issues. Some studies suggest REM sleep might help process stressful or traumatic events.

So, REM sleep strongly influences our emotional stability, creativity, and learning abilities.

But What Does REM Sleep Have to Do with Alcohol?

While alcohol makes it feel like we fall asleep faster, the deep sleep it initially induces is replaced by lighter sleep, especially during the second sleep cycle, when REM sleep would normally dominate.
Alcohol practically wipes out the REM phase of our sleep cycle, causing us to lose all the benefits that REM sleep provides.

Even if someone falls asleep faster under the influence of alcohol, the overall quality of their sleep is generally worse. Alcohol disrupts the architecture of sleep, reducing its restorative effects.

In the long term, this can have many harmful effects, especially during the first few years of life. Early developmental stages, including the fetal period and infancy, are critical for brain and nervous system development.

REM sleep disturbances may affect brain development and contribute to certain neurological disorders. According to the research of renowned sleep scientist Matthew Walker, a absence or regular disruption of fetal REM sleep might be linked to later Autism development.

If a breastfeeding mother has a blood alcohol level of 0.08%, her breast milk contains the same level. Even just one glass of wine during breastfeeding can significantly impair an infant’s REM sleep, which can cause permanent damage since the brain cannot later make up for REM sleep deficits.

In adulthood, frequent REM sleep disturbances impair learning ability, general emotional state, and significantly contribute to the development of depression.

Overall, it’s clear that alcohol negatively impacts sleep quality, which can harm health and well-being in the long run. Reducing alcohol consumption, especially before bedtime, can improve sleep quality and general health!