5 surprising ways alcohol can hurt your sleep quality
Many people are surprised to learn that drinking alcohol can actually hurt your sleep more than help it. If you’ve ever had an alcoholic drink close to bedtime—let’s say within four hours or so— you’re likely aware that drinking can make you feel drowsy. Beer, wine, and other alcoholic spirits are depressants, and up to 20% of Americans use alcohol as a tool to help fall asleep.
This may be a problem.
Alcohol affects how your body regulates sleep, not to mention the overall quality of your sleep, in a number of negative ways. These can range from waking up in the middle of the night to increased snoring to an increased impact on sleep disorders, and more.
Breathing problems surface—or worsen
Alcohol is a muscle relaxant. Sleep relaxes the muscles, too. Relaxation during sleep is normal, but when you add alcohol to the mix, your throat muscles can relax even more than usual. And if you’ve had a drink within four hours of bedtime, your likelihood of snoring and experiencing sleep apnea are much higher.
A recent combined analysis of 21 sleep studies found that sleep apnea increases by 25% after consuming alcohol. What’s so bad about sleep apnea? For one, it completely changes your respiratory functions during sleep and can have some very serious consequences.
An apnea is a complete stoppage of breathing due to your throat being too relaxed and gravity pushing down on your soft palate, tongue, or neck. Your blood pressure skyrockets, and when your brain realizes there isn't enough oxygen, it wakes you up to get you breathing again. This becomes a problem when you wake over and over again throughout the night. Repeated awakenings lead to a deficit in deep, restorative sleep.
Trouble breathing from alcohol consumption also may explain the morning headaches associated with hangovers. Carbon dioxide levels increase during sleep and this leads to increased pressure within the head. These types of headaches typically fade in the first few hours of the morning as breathing, oxygen levels, and carbon dioxide levels are returned to normal.
Additionally, research has linked the combination of sleep apnea, snoring, and alcohol consumption with an increased risk of heart attack, arrhythmia, stroke, and sudden death.
You experience dueling sleep rhythms
Since alcohol is a depressant, consuming it before bed can lead to enhanced slow-wave sleep patterns, the kind found in deeper stages of sleep where your memory and learning capabilities are renewed. These kinds of brain functions are called delta activity. But at the same time, alcohol also turns on alpha activity, a type of brain pattern more commonly seen when you’re awake. These two conflicting sleep rhythms happening simultaneously create an environment for disruptive stimuli to affect the quality of your sleep.
REM sleep stage is blocked
During the REM sleep stage, your brain waves change and process the events from the previous day, producing vivid dreams. REM sleep also affects your mood and memory.
After consuming alcohol, however, the ability to get to REM sleep is sometimes blocked. Since REM sleep is where renewal and restoration occurs for both the body and mind, not receiving the many benefits is detrimental to the quality of sleep you get that night as well as how you feel the next day. A lack of REM sleep can leave you feeling tired, irritable, and unfocused.
Your circadian rhythms can be disrupted
What’s a circadian rhythm? It’s a special system that keeps our bodies synced up with the natural patterns of the 24-hour day. While it doesn’t operate exactly to the minute on a 24-hour schedule, the circadian rhythm is the closest thing we have to an “internal clock." This rhythm sends signals to our body throughout the day and night that it’s time for certain activities to occur, like the release of hormones, the digestive process, the regulation of our body temperature, when we feel awake and alert, and when it’s time to go to sleep.
Adenosine is a sleep-inducing chemical in the brain that is released after drinking alcohol. Although your body is already capable of preparing for sleep on its own, adenosine comes in and expedites the process, often triggering a faster onset of sleep. But the effects of adenosine disappear just as quickly as they arrive, causing you to wake up long before you’ve actually had a restful night of sleep.
Late-night bathroom visits increase
By the time you’re an adult, your body has trained itself to put your bladder into a sort of hibernation state when you go to bed. As you fall asleep, your body gets the signal that for the next eight hours or so, trips to the bathroom are not on the agenda.
That said, alcohol is a diuretic, which works in direct contrast to how your body would normally function during sleep. This results in waking up in the middle of the night and jolting yourself out of these important, restorative sleep stages to visit the restroom. The more your normal sleep patterns are interrupted, the poorer quality of sleep you receive.
Monitoring your alcohol consumption may give you a better idea of how alcohol affects your sleep quality in terms of breathing, restlessness, and oxygen levels. Notice the amount of alcohol consumed, as well as how close to bedtime the consumption occurs. Your assessment may not necessitate total abstention from alcohol, but you may end up deciding to nix that after-dinner nightcap.
One sleep study found some sobering data on sleep apnea patients who have two or more drinks a day. They are five times more likely to be involved in a traffic accident not from drunk driving, but from falling asleep at the wheel. This is due to sleep apnea robbing you of a night of quality sleep, leaving you tired and fatigued the next day.
Taking a look at how your alcohol consumption affects your sleep is an important step in your journey to better sleep health.
Brandon R. Peters, M.D., is board-certified in both neurology and sleep medicine and currently practices at Virginia Mason Medical Center in Seattle. He is also a Clinical Affiliate at Stanford University's School of Medicine in the Department of Psychiatry and Behavioral Sciences. His latest book, Insomnia Solved, is available on Amazon.