5 Ways Alcohol Affects Your Sleep Cycle

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Alcohol is a sedative, but it can negatively alter neurotransmitters that control your sleep cycle. The two major ones are gamma-aminobutyric acid and glutamate. Drinking also increases adenosine, which unnaturally induces sleep and harms your entire cycle. The stages of sleep become shorter when you drink, with deep sleep and REM taking the greatest hit. They’re important for proper brain function, but if you don’t get enough, your mental health may suffer.

After a long day, there’s nothing like a nightcap. This can be anything from a cold brew to a glass of red. It’s an easy way to fall asleep, right? Well, not really. There’s no doubt that alcohol can put you to bed, but it can seriously disturb your cycle.

Of course, the occasional drink won’t hurt. But if you depend on alcohol to catch some Z’s, you might be doing more harm than good.

Here are five major ways alcohol can affect your sleep cycle.

1. Alters Neurotransmitters

Ways Alcohol Affects Your Sleep Cycle: Alters Neurotransmitters

The effects of alcohol on sleep come down to one thing: neurotransmitters.

These brain chemicals act on different nerve cells, or neurons, in the brain. Specifically, gamma-aminobutyric (GABA) plays a big part. GABA inhibits the neurons that keep you awake, which then promotes sleep.1 It’s basically in charge of your entire sleep cycle.

When you drink, GABA gets thrown out of whack. It has a hard time making new nerve signals that keep your cycle in check. This can happen even at low doses.

Alcohol also affects glutamate, a major neurotransmitter that controls wakefulness. It disrupts your cycle by stopping glutamate receptors from getting signals in the first place.

2. Increases Adenosine

Ways Alcohol Affects Your Sleep Cycle: Increases Adenosine

Drinking also increases your levels of adenosine. This molecule isn’t a neurotransmitter, but it controls the signals of other neurotransmitters, like GABA and glutamate. When adenosine rises, you’re more likely to fall asleep. This mechanism explains alcohol’s sedative effects.2

At first, it might seem like a good thing. But when sleep is induced by alcohol, you’re more likely to have poorer sleep quality. The side effects are more harmful than you think.

The bottom line? Your sleep-wake cycle can’t operate naturally when you drink.3

3. Reduces First Stages Of Sleep

Ways Alcohol Affects Your Sleep Cycle: Reduces First Stages Of Sleep

Alcohol also messes with the specific stages of sleep. Normally, the cycle goes like this: stages 1, 2, 3, 4, and REM. The sleep cycle repeats several times a night, starting again at stages 1 and 2, the lightest periods of sleep.

When you first went to bed, alcohol’s sedative effects made stage 1 pretty heavy. But by the time you re-start a cycle, your body has metabolized some alcohol. It attempts to re-adjust by lightening the second stage 1. As a result, you’ll be more likely to wake up.4

4. Shortens Deep Sleep

Ways Alcohol Affects Your Sleep Cycle: Shortens Deep Sleep

Your deepest rest happens during stages 3 and 4. Sleep waves alternate between slow and fast in stage 3, then become completely slow in stage 4. If you wake up during this time, you’ll feel extremely groggy and tired.5

Alcohol reduces the proportion of stages 3 and 4. Throughout the night, slow-wave sleep becomes shorter and shorter. It might even become non-existent.6

5. Suppresses REM

Ways Alcohol Affects Your Sleep Cycle: Suppresses REM

Rapid eye movement (REM) sleep occurs after stages 3 and 4. Your most bizarre dreams happen during this time!

This stage also encourages the creation of proteins and cells, making it important for normal brain function. Even learning and mental skills depend on adequate REM sleep.7 Clearly, it isn’t just for dreaming.

Regardless of how much you drink, alcohol delays the first REM stage. It’s actually alcohol’s most significant effect on the sleep cycle. By morning, total REM sleep will be suppressed, creating a negative effect on your brain.8

If you drink alcohol, do so in moderation. Men should have no more than one to two drinks per day, and women should have no more than one. Drinking more than this will impact not just your sleep, but your overall health.9

Can’t fall asleep? Try natural ways to catch some Z’s. Yoga, aromatherapy, and meditation are excellent options.

References   [ + ]

1. Siegel, Jerome M. “The neurotransmitters of sleep.” J Clin Psychiatry 65, no. Suppl 16 (2004): 4-7.
2, 4, 6.Roehrs, Timothy, and Thomas Roth. “Sleep, sleepiness, and alcohol use.” Alcohol research and Health 25, no. 2 (2001): 101-109.
3.Insomnia and Alcohol and Substance Abuse. Office of Alcoholism and Substance Abuse Services.
5.What Is Sleep? American Sleep Association.
7.What Is Sleep? American Sleep Association.
8.Ebrahim, Irshaad O., Colin M. Shapiro, Adrian J. Williams, and Peter B. Fenwick. “Alcohol and sleep I: effects on normal sleep.” Alcoholism: Clinical and Experimental Research 37, no. 4 (2013).
9.Alcohol And Heart Health. American Heart Association.

Disclaimer: The content is purely informative and educational in nature and should not be construed as medical advice. Please use the content only in consultation with an appropriate certified medical or healthcare professional.

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