Alcohol has a place in every culture, one way or another. We drink in ceremonies to celebrate, mourn and socialize. At times, drinking can become a lonely habit, very distant from its ceremonial roots and drinking excessively can become an addiction with many negative consequences to our health.
Alcohol is a chemical that is very easily absorbed and distributed throughout our bodies and the brain. It is metabolised by enzymes in our liver and its metabolites are eventually excreted in our urine. However, the rate by which alcohol is absorbed and metabolised varies depending on our genetics and the versions of the enzymes that we carry, whether we had food with our drinks, our gender, our age and even the time of day.
Alcohol is a sedative which means it suppresses the brain’s activity. Anxiolytic drugs like benzodiazepines act in a similar way to reduce anxiety, albeit with plenty of side effects and risks. Having a drink or two in the evening may feel like a natural thing to do, a helpful push towards the direction we would like to go. The aim is to wind down, relax and ease ourselves to sleep, and alcohol can certainly do that.
Alcohol promotes sleepiness by increasing the levels of adenosine, a chemical in the brain that accumulates naturally as we spend time awake and process information. The more time we spend awake the more need or pressure we feel to go to sleep. Adenosine in turn suppresses the activity of acetylcholine, which naturally promotes wakefulness and also promotes REM sleep.
Studies find that drinking alcohol helps us go to sleep faster and experience deeper sleep in the first hours of the night when we typically go through our non-REM sleep, including slow-wave sleep, and this is true across ages and genders. The effects are greater with greater doses of alcohol, so it feels that it is working. We may fall asleep on the couch, or we may just make it to bed.
However, this sense of triumph and sweet taste of success is short-lived, especially with higher doses of alcohol. The ease with which we fell asleep is soon replaced by sleep disruption. Alcohol interferes with REM sleep, which is the stage that follows NREM sleep at the end of each 90-min sleep cycle. REM sleep is characterized by rapid eye movements, increased activity in the brain coupled with body paralysis. We are dreaming our most fascinating dreams during this stage. Having a few drinks disrupts REM sleep by delaying its onset and by reducing the time spent in REM when it does occur. In addition, alcohol leads to multiple awakenings during the second half of the night, and this is the case even with low doses, of one or two drinks.
With chronic consumption, there is further sleep disruption, insomnia and sleepiness during the day. These symptoms of insomnia can predict relapse in those who have managed to quit drinking so that they are more likely to revert to alcohol to make the symptoms go away and to be able to get some sleep.
But putting sleep aside, is alcohol harmful or beneficial to our health? This question has proven more complex than it perhaps should have been, given that alcohol is toxic and can be lethal in high doses. This toxicity may go unnoticed if we consume small amounts but with higher doses, it becomes more evident. Yes, alcohol kills our brain cells and increases the risk of cancer, liver disease, injuries and tuberculosis, however, at times studies have reported a more complex relationship. Several studies that look at associations have been finding a relationship between moderate consumption of alcohol and decreased risk of cardiovascular disease. At times this evidence was linked to particular types of alcoholic drinks, with red wine for example deemed as the ‘good’ drink and beer or spirits as the ‘bad’ drinks.
Although there are some beneficial chemicals in red wine like resveratrol that are not found in other drinks, their quantities are too small to result in any substantial benefit that would outweigh the risks. In addition, the associations that have been identified previously seem to be due to healthier lifestyle choices such as exercising, adopted by people who drink moderately overall, and not due to the moderate consumption of alcohol per se. What seems to be agreed upon is that there may be a small benefit to the vasculature that can be helpful for older people who overall have a greater risk for cardiovascular complications, such as heart attack and stroke. The risk for that however is much lower in younger people. According to the latest studies, alcohol is harmful and should be avoided by those younger than 40 years of age. There is no safe dose of alcohol for them. The risks outweigh any possible benefits on the vasculature. For older adults (40+) there may be some benefit to the vasculature with light to moderate alcohol consumption, although this does not apply to arrhythmias, as these tend to get worse with alcohol. Having said that, some studies found that it is the genetic makeup of each of us that dictates whether or not we may benefit from alcohol, which is something that we are not in a position to know at this point. Moreover, in those older, metabolism slows down so alcohol lingers longer in the body, increasing the risk for injuries and falls and it compromises cognitive processes and sleep which suffer more in this age group to begin with. Also, the same possible benefits of alcohol to the blood vessels can be achieved with exercise, which yields several additional benefits such as decreasing the risk for cancers and numerous other diseases. So exercise is by far superior to alcohol and with no side effects, besides feeling good about ourselves and the world.
Despite what we know, alcohol remains the most widely used over-the-counter sedative medication. Drinking is a way for people to self-treat their anxiety and sleep problems even though they are increasing the risk of several health conditions in the process. Sleep may come more easily but it is subsequently disrupted. Multiple awakenings may not be something that we remember but we may be less alert the next day and find ourselves seeking the help of stimulants such as coffee and energy drinks. Many argue for a hopeless cycle of stimulant consumption to increase alertness during the day and alcohol consumption to relax and suppress activity at night, perpetuating a situation that disturbs our natural processes of wakefulness and sleep.
Others focus on the impact of REM deprivation which is the stage of sleep associated with dreaming and resolving our emotions, especially the negative ones. REM sleep also supports our creative minds, the ability to connect the dots and find solutions to bothersome situations. Getting less REM does not seem like a good idea. So, no matter what we prioritize in our lives, there must be a healthier way to help us get there.
GBD 2020 Alcohol Collaborators. Population-level risks of alcohol consumption by amount, geography, age, sex, and year: a systematic analysis for the Global Burden of Disease Study 2020. Lancet. 2022 Jul 16;400(10347):185-235. doi: 10.1016/S0140-6736(22)00847-9.
Li H, Xia N. Alcohol and the vasculature: a love-hate relationship? Pflugers Arch. 2023 May 11. doi: 10.1007/s00424-023-02818-8.
Posted in sleep on Jun 01, 2023