Does alcohol reduce REM sleep?
Yes, and this is the most consistent finding across all the studies. REM sleep is the stage where most dreaming occurs and is important for memory consolidation and emotional regulation. A 2024 meta-analysis that combined data from 27 separate studies found that even a low dose of alcohol — roughly two standard drinks — reduces REM sleep, and the effect gets worse with higher doses [3]. This means even a modest drink before bed will likely cut into your dreaming sleep.
A large real-world study using under-mattress sleep trackers on over 85,000 people confirmed this: on nights when participants reported drinking alcohol, their REM sleep percentage dropped by 1.71% compared to non-drinking nights [5]. That might sound small, but across a full night's sleep it represents a meaningful loss of restorative sleep. Another study in people with COPD found that a moderate dose of alcohol (0.5 g per kg of body weight, about 3–4 drinks) reduced REM sleep by 3.1% of total sleep time [4]. The pattern is clear: alcohol consistently suppresses REM sleep.
Does alcohol help you sleep deeper at first?
Yes, but this is a trade-off, not a benefit. Alcohol can increase slow wave sleep (deep sleep) in the first part of the night, which is why many people feel it helps them fall asleep and sleep heavily. The large real-world study found that alcohol use was associated with a 1.38% increase in deep sleep percentage [5]. However, this early boost comes at the expense of REM sleep later in the night, as noted above.
The effect on deep sleep may also differ between men and women. One study of 23 participants found that women showed a stronger increase in slow wave sleep in response to high breath alcohol concentration than men did, suggesting women may be more sensitive to alcohol's sedative effects [1]. But this same study also found that higher peak alcohol levels were linked to less slow wave sleep in women, which complicates the picture. The bottom line: alcohol may deepen sleep initially, but it disrupts the overall balance of sleep stages.
Does alcohol cause you to wake up more and sleep later?
Yes, alcohol fragments sleep and shifts your circadian rhythm. The large real-world study found that on drinking nights, people experienced 3.97% more wakefulness after sleep onset — meaning they spent more time awake during the night [5]. This is likely due to the body metabolizing alcohol and the rebound effects as blood alcohol levels drop.
Alcohol also delays your wake-up time. A study of 251 women with sleep and pain complaints found that each additional alcoholic drink was associated with an 8-minute delay in waketime the next morning [6]. So five drinks would push your wake time back by about 40 minutes. This suggests alcohol disrupts the circadian rhythm, making it harder to wake up at your usual time. Interestingly, one study found that pre-sleep breath alcohol concentration (up to 0.087 mg/L) did not strongly predict sleep changes when controlling for non-alcohol nights [2], but this may be because the effects are more pronounced at higher doses or over multiple nights.
About These Sources
This answer is built on 6 peer-reviewed studies — published from 2016 to 2026, 3 from 2024 or later, 4 in Q1 journals — selected as the most relevant from 6 studies that passed quality screening, drawn from 48 papers retrieved from a database of over 500 million.
Sources used in this answer
062 Sex Differences in Slow Wave Sleep Following Evening Binge Alcohol Consumption
In a randomized crossover study of 23 participants, binge alcohol consumption (4–5 drinks) increased slow wave sleep in women more than men, and higher peak breath alcohol was linked to less slow wave sleep in women, suggesting sex differences in alcohol's sedative effects.
0221 Pre-Sleep Breath alcohol concentrations (psBrAC) and sleep polysomnography (PSG)
In a crossover study of 30 healthy adults, pre-sleep breath alcohol concentration (mean 0.066 mg/L) was not significantly associated with changes in sleep stages or sleep latency when controlling for non-alcohol nights, suggesting minimal effect at moderate levels.
The effect of alcohol on subsequent sleep in healthy adults: A systematic review and meta-analysis
A meta-analysis of 27 studies found that even low-dose alcohol (≈2 drinks) reduces REM sleep, and high-dose alcohol (≈5 drinks) shortens sleep onset latency but worsens REM disruption, with a clear dose-response relationship.
Alcohol at bedtime induces minor changes in sleep stages and blood gases in stable chronic obstructive pulmonary disease.
In an open-label study of 26 COPD patients, a moderate alcohol dose (0.5 g/kg) reduced REM sleep by 3.1% of total sleep time and slightly increased carbon dioxide levels during sleep, but had minimal respiratory effects in most participants.
1278 Associations Between Self-Reported Daily Lifestyle Behaviors and Objective Sleep Parameters in a Large, Real-World Sample
In a large real-world study of over 85,000 participants (2.3 million nights), alcohol use was associated with 3.97% more wake after sleep onset, 1.71% less REM sleep, and 1.38% more deep sleep, using within-person comparisons.
0998 Sleeping It Off: Alcohol, Cannabis, and Alterations in Bedtime and Waketime in Women with Sleep and Pain Complaints
In a daily diary study of 251 women with sleep and pain complaints, each additional alcoholic drink was associated with an 8-minute delay in waketime the next morning, indicating a dose-dependent circadian disruption.