What it is:
Whether we're pairing wine with dinner, socializing over beer, or indulging on the rocks at the end of a workday, alcohol is a globally used psychoactive substance.
When used in moderation, it doesn't necessarily contribute to poor health. However, it's helpful to understand how alcohol can affect our sleep – particularly as sleep is essential for total body health and longevity.
It's a common misconception that alcohol helps us sleep. While the initial effects can be sedating and even sleep-inducing, it gets more complicated as our body metabolizes and clears it from our system. Understanding this process can help us decide when and what to imbibe.
The purported claims:
Being mindful of what and when we drink can help:
Reduce nighttime awakenings
Support healthy melatonin secretion
Promote adequate REM sleep duration
Prevent snoring/breathing disruptions
Regulate core body temperature
What the science says:
Ethanol, the type of alcohol found in wine, beer, and spirits, is a small molecule that binds to cells throughout the body. Unlike many other psychoactive substances, ethanol is "non-selective." It doesn't pick and choose the tissues and organs it targets. For this reason, alcohol abuse executes widespread damage throughout the body.
After a drink, ethanol enters the bloodstream and works its way around the body. It enters the brain, as well as various other tissues and organs. It disrupts hormone signaling, promotes fat accumulation in the liver, and increases core body temperature.
The first drink sedates us slightly, pairs back some of our inhibitions, promotes feelings of euphoria, and perhaps even gives us a little more confidence than usual. But it also slows our reaction time, impairs motor coordination, and disrupts most other brain functions. The more we drink, the more noticeable this becomes.
A "nightcap" is thought, by many, to aid the wind-down process and promote better sleep, but studies do not support this. Alcohol consumed too close to bedtime can fragment our sleep, suppress melatonin secretion, suppress rapid eye movement (REM) sleep, increase snoring, and elevate core body temperature. Combined, these can result in non-restorative sleep, leaving us feeling under-rested the next day. It can even worsen sleep quality the following night.
The liver metabolizes alcohol at about one hour per glass of wine. While the alcohol is in our system, it depresses our nervous system and might even allow us to drift off to sleep more quickly. However, once it is cleared from our bloodstream, we often experience a rebound effect in alertness to compensate for the sedated time. This can often wake us up from sleep and make it difficult to drift off again.
Consumption of moderate to high levels of alcohol can also suppress melatonin secretion. This hormone is released by the pineal gland in the brain at night during darkness and is essential for helping us fall and stay asleep. As well as playing an important role in our sleep schedule, melatonin is a powerful antioxidant that combats cell damage throughout the body. Moderate or excessive drinking can deprive us of a healthy nightly melatonin dose, which is vital for repairing the body's many tissues.
Alcohol can interfere with our sleep stages too. Typically, our sleep cycles are rich in slow-wave (also called "deep") sleep during the first half of the night. Deep sleep is considered to be the crucial stage of rest and repair. As morning approaches, we trade off slow-wave sleep for REM sleep.
Moderate amounts of alcohol can increase deep sleep and suppress REM sleep.
REM sleep is essential for many reasons, such as:
Processing emotions
Consolidating certain types of memory
Altering our mood and well-being
Consequential rebound effects on following nights can also occur, leading to a domino effect of sleep disturbance. Utilizing caffeine in these circumstances to compensate for sleep loss can lead to reliance on alcohol to depress our system in the evening and caffeine to stimulate the following day.
Breathing disruption and snoring occur during sleep due to alcohol's effect as a muscle relaxant on our airway. The narrowing of the passage during sleep restricts oxygen flow and forces the body to breathe through the mouth rather than filter through nasal passages.
Lastly, about an hour before we go to bed, our core body temperature decreases alongside melatonin release. Our brain needs this signal to begin the transition to sleep. Alcohol increases core body temperature at night, so consuming it too close to bedtime works against our natural sleep process.
Our take:
Preference for and sensitivity to alcohol vary from person to person. Whether or not it is consumed and how frequently – if at all – is a personal decision.
Drinking is less likely to affect your sleep if you:
Don't drink every day
Reduce the amount that you drink when you do
Leave as much time as you can between your last drink of the day and bedtime. Sleep experts recommend 4 hours, if possible.
Will this benefit you?
Consuming alcohol for its sedating properties will not benefit your sleep. If you are trying to cultivate more energy during the day, cutting down on your evening, alcohol intake can help.
Still curious to try it? If you do, here's what to keep an eye on:
Exchanging out evening alcoholic beverages for an occasional alternative strategy can help. Try herbal tea, one tablespoon of apple cider vinegar in sparkling water, or warm milk.
On days that you drink, consider opting for an afternoon or evening happy hour rather than a nightcap right before bed to allow your body time to metabolize the alcohol and support better sleep. If an evening social event calls for a beverage, opt for something you enjoy in smaller amounts. Consume one glass of water for every alcoholic beverage.
Resist overcompensating with caffeine, and opt for a walk or light exercise in the sunshine to reset your body clock.
References and additional reading:
Alcohol and circadian rhythms - https://pubmed.ncbi.nlm.nih.gov/31809833/
Red wine and cardiovascular health - https://pubmed.ncbi.nlm.nih.gov/31597344/
Alcohol and sleep - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5821259/
"Breathe" by James Nestor - https://www.amazon.com/Breath-New-Science-Lost-Art/dp/0735213615
Huberman lab podcast ft. Dr. Matthew Walker - https://hubermanlab.com/dr-matthew-walker-the-science-and-practice-of-perfecting-your-sleep/
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