More than one in ten people use alcohol to overcome stress-related insomnia. However, evidence shows that alcohol does not improve sleep. On the contrary, when alcohol passes through the body, it produces some biochemical effects, which often leads to worse sleep.
Does alcohol help sleep?
Although drinking alcohol before going to bed helps you fall asleep faster, this popular drink has a negative impact on overall sleep quality. When you drink alcohol before going to bed, your body metabolizes the alcohol throughout the night. As the blood alcohol level rises and falls, alcohol has different effects on your sleep.
How does alcohol affect sleep?
Alcohol may shorten the overall sleep time and interrupt sleep, which can lead to fatigue and sleepiness the next day (e.g. hangover). The more alcohol you drink, the greater the negative impact on sleep.
Alcohol changes sleep stages
For most people, alcohol induces deeper sleep than usual in the first half of the night, followed by interruption of sleep in the second half of the night.
On a normal night of sleep, we cycle through light sleep, deep sleep, and rapid eye movement (REM) sleep. Each sleep stage plays an important function, but deep sleep and rapid eye movement sleep are considered to be the most important stages of physical and mental recovery.
Alcohol was originally used as a sedative, increasing the proportion of deep sleep at the beginning of the night. However, as the effects of alcohol begin to fade, the body spends more time in light sleep, which is less robust and may lead to more night awakenings. Because of these frequent awakenings, people tend to reduce their sleep time after drinking alcohol.
Studies have found conflicting information about how alcohol affects rapid eye movement sleep. Alcohol seems to have been delaying the first onset of REM sleep, and higher doses of alcohol seem to reduce the total amount of REM sleep. Inhibition of REM sleep can have adverse consequences for memory consolidation and other cognitive processes.
People who continue to drink too much alcohol may eventually develop tolerance to its initial sedative effects. Research on chronic alcohol users found that these people’s sleep patterns are usually disrupted, slow-wave sleep is reduced, and rapid eye movement sleep is increased.
Alcohol affects adenosine levels and sleep homeostasis
Alcohol increases the level of adenosine, which is a key component of the balance drive. Static drive is responsible for maintaining the balance of our body. It is one of the main mechanisms that regulate the sleep-wake cycle. When we are awake for too long, the balance drive promotes sleep by raising the level of adenosine.
After drinking a few glasses, these increased adenosine levels put us into deep sleep. However, once the body realizes that it has too much slow-wave sleep, the steady-state drive compensates for it by allowing us to reduce deep sleep later in the night.
In the short term, these changes in our sleep patterns can cause restlessness in the second half of the night. In the long term, frequent disturbances to our natural sleep cycle may change the static drive in a more lasting way. Long-term alcoholics do not seem to exhibit the deep restorative sleep that most people exhibit after sleep deprivation, which suggests that the homomorphic drive no longer functions as it should.
Alcohol changes melatonin and circadian rhythm
Alcohol may also have some effects on sleep by affecting the circadian rhythm. The circadian rhythm is responsible for fixing the body in a 24-hour cycle. As part of this 24-hour cycle, the body releases a hormone called melatonin to prepare us for sleep at night. Earlier studies have found that drinking alcohol before going to bed reduces melatonin levels and interferes with core body temperature, which in turn affects sleep quality.
A newer study found that a dose of alcohol had no effect on the circadian rhythm of rodents. However, the researchers suggested that perhaps these effects on the circadian rhythm only appear after several consecutive days of drinking.
To support the link between alcohol and melatonin, researchers have noticed that people who suffer from severe alcohol withdrawal tend to have less pronounced levels and release of melatonin.
Alcohol can increase symptoms of snoring and obstructive sleep apnea
A lot of evidence shows that alcohol can aggravate the symptoms of snoring and obstructive sleep apnea. These sleep-related breathing difficulties can occur when the soft tissue collapses and blocks the upper airway. In mild cases, breathing difficulties can cause snoring. In more severe cases, the individual suffers a momentary interruption of breathing, followed by waking, interrupting the progress of the sleep phase.
Alcohol is a muscle relaxant, so drinking alcohol before going to bed can make a person more likely to have a blocked airway. People who usually snore or have obstructive sleep apnea tend to show more severe snoring and lower blood oxygen levels after drinking, especially when they drink near bedtime.
People who drink alcohol regularly are 25% more likely to develop obstructive sleep apnea, although this link may be partly due to other common risk factors, such as obesity.
Alcohol exacerbates existing health conditions and sleep disorders
Many people turn to alcohol to cope with feelings of difficulty, but if alcohol interferes with sleep, it may eventually have the opposite effect. For example, people with moderate or severe anxiety who use alcohol in the hope of sleeping better are actually more likely to have sleep problems.
Similarly, research on bereaved people found that using alcohol to cope with sadness increases the risk of major depression, and major depression itself is a risk factor for sleep disorders.
Unsurprisingly, research on patients with insomnia also found that heavy drinking can exacerbate insomnia. People who don't feel energetic after waking up may be more likely to rely on alcohol again the next night to help them fall asleep, leading to a counterproductive drinking pattern.
Can you drink within a certain range?
Be cautious when drinking alcohol before going to bed, because alcohol may have a greater impact on sleep than you realize. This may be especially true if you drink to help you fall asleep faster, and then unknowingly experience sleep interruptions at night. Since even a small amount of alcohol can affect your sleep, the overwhelming consensus in the medical community is that alcohol is not an appropriate sleep aid.
Since alcohol affects everyone differently, it is important to understand where your limits are and how much alcohol you can drink before it starts to affect your sleep. If you are looking for ways to improve sleep, a simple start is to adopt healthy sleep hygiene habits, such as maintaining a consistent sleep time and creating a calm bedroom environment.
