Sleep Health

Sleep and Alcohol

By Helga George

Practically everyone who drinks alcohol realizes that you go to sleep more quickly after having a nightcap. As many as 20% of Americans drink alcohol to fall asleep on a regular basis according to the National Sleep Foundation.

Alcohol is a depressant – it slows down your central nervous system. This causes your muscles to relax and your brain function to slow down. Therefore, you fall asleep more quickly compared to normal.

If that were all that alcohol did to your sleep cycle, it would be fine. However, alcohol consumption before bed greatly affects how you sleep later in the night by inhibiting your sleep quality. A key problem of using alcohol as a sleep aid is that it affects your REM sleep and your whole circadian rhythm.

Why Does REM Sleep Matter?

About one-quarter of our normal sleep phase involves REM, short for rapid eye movement. This is the phase of sleep where we dream, and it is during this cycle that our bodies do most of their healing and restore themselves.

In addition, your brain makes chemicals that directly affect your mood during REM sleep. This is part of the reason why a reduction in this type of sleep can make you feel cranky and irritable.

Even if you only drink low or moderate amounts of alcohol at bed, this can dramatically reduce the amount of your REM sleep.

If your REM sleep is disturbed, you will wake up groggy and unfocused. You may even suffer from impaired motor skills and memory.

If this continues to happen over time, you stand a good chance of developing insomnia.

Alcohol Can Give You Night Sweats

Proper regulation of your body temperature is a key component of getting a good night’s sleep. All is well and good when you first go to sleep after drinking. At first, the alcohol cools your body down.

However, once the alcohol wears off, your body’s temperature will spike up. This can cause night sweats and is likely to wake you up.

How Else Does Alcohol Disrupt Sleep?

As you sleep, your body breaks down the alcohol you drank. Once it is gone, it is no longer affecting your brain. This can affect your brain waves and can be enough to wake you up.

Another thing that happens as you sleep is that your body starts to respond to changes in your metabolism and digestion in ways that can wake you up. For example, your body needs more sugar and water, and your digestive system has more acid.

Since alcohol is a diuretic and causes you to have to urinate frequently, you are more likely to get up and go to the bathroom if you drink it at bedtime.

You may also dream more vividly because you will have more abrupt transitions between your sleep stages if you drink alcohol at bedtime

All these effects of alcohol combine to create a perfect storm of ruining your sleep and hurting your ability to function the next day.

Alcohol Can Throw Your Circadian Rhythms Into Disarray

Your body has a normal group of cycles that are in synch due to a biological switch. These 24-hour cycles are known as circadian rhythms. They regulate almost everything that your body does, including your immune system, metabolism and sleep time.

When alcohol affects your sleep patterns, it is messing with your circadian rhythms – and therefore, most aspects of your body’s functions.  

Another way in which alcohol use at bedtime affects your circadian rhythm is by inhibiting the production of melatonin – one of the major hormones that control our sleep/wake cycles.

Without adequate melatonin, your body will respond poorly to the changes in light intensity that signal that it is time to go to sleep. In addition, you are more likely to develop sleep disorders.

Both Alcoholism and Recovery Can Affect Your Sleep

If you feel like you need alcohol for sleep, you will drink on a regular basis. At a certain point, as the sedative effects of the alcohol wear off, you will need more alcohol to feel the same effects. This can lead to alcoholism.

Ironically, if you stop drinking alcohol, your sleep may still be disrupted. It can take months and even as much as a year for your sleep pattern to return to normal once you quit drinking.

Therefore, insomnia is a common symptom among recovering alcoholics. In fact, a study in the Journal of Addiction Medicine found that people in recovery are five times more likely to suffer from insomnia than the general population. This can lead to relapses.

Alcohol at Bedtime Can Lead to Sleep Apnea

Heavy snoring used to be considered just a nuisance. However, in recent years, medical professionals have found that it is frequently a sign of sleep apnea.

Obstructive sleep apnea is a serious condition in which the throat muscles relax during sleep and close in, blocking the intake of air. If you have this condition, you wake up numerous times during the night gasping for breath. This can happen as many as hundreds of times a night – ruining any chance of getting a good night’s sleep.

Your risk of dying is five-fold higher if you have this type of sleep apnea because your oxygen levels can get perilously low. This can result in a heart attack or stroke.

Alcohol can make this condition worse and even cause you to display these symptoms for just one night even if you don’t normally suffer from sleep apnea. This is because alcohol use can relax your tongue and upper respiratory tissues, causing your throat tissue to cave in while you sleep.

It’s Even Worse Than We Thought

In the first study of its kind, researchers in Finland studied 4,098 adult men and women by measuring their heart rate variability (HRV) and published their results in JMIR Mental Health.

This technique measures the time between heartbeats. It is a good way to examine the quality of the restful state of sleep.

The researchers studied the participants’ HRV on two nights – one where they drank alcohol and one where they did not. They honed in on the first three hours after drinking alcohol.

Just one drunk reduced the restorative quality of the sleep, and it got worse with increased alcohol consumption. The percentage of sleep impaired is shown below:

  •      One drink – 9.3%
  •      Moderate amounts of alcohol – 24%
  •      High amounts of alcohol – up to 39.2%

Strangely, young people suffered more harmful effects from alcohol than seniors, and there were no significant differences between men and women.

The researchers concluded, “It’s hard to overstate the importance of sleep.”

Why Does it Matter to Get a Good Night’s Sleep?

Sound sleep restores both our minds and bodies. In fact, optimal brain function depends on sleeping well. It is during sleep that your mind processes memories and learning. Problem-solving and concentration skills are all honed during sleep.

People that routinely get inadequate sleep are prone to heart disease, obesity, diabetes and stroke. Sleep deprivation is considered to be as serious a factor for car accidents as driving under the influence.

Alcohol is such a common part of everyday life for many people that we tend to forget just how bad it is for you. How many people even know that alcohol is a carcinogen?

There is a good reason why some doctors recommend just having a few drinks a week. Maintaining such a schedule will improve your sleep and keep you from ruining it by drinking alcohol at bedtime on a regular basis.


About the Author

Helga George, Ph.D.

Dr. George obtained three degrees in the plant sciences culminating with a Ph.D. from Cornell University before transitioning to writing full time. Despite her obsession with plants, most of biology interests her. Helga is drawn to sleep science out of a combination of intellectual curiosity and her own sleep problems ranging from sleep apnea to delayed sleep phase (i.e., being a hardcore night owl). She enjoys explaining science to laymen in terms that they can understand and relishes the opportunity to look behind the veil of sleep and relay the benefits provided by quality sleep.

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