Many people see alcohol consumption as a promoter of drowsiness. However, the opposite may be true.
The build-up of tolerance and its effect on brain chemistry can disturb sleep patterns within a relatively short time.
Regular heavy alcohol use is likely to disrupt sleep patterns seriously.
Alcohol is a sedative that many people consume in the evening to help them unwind and ultimately sleep.
This may initially work for them, but tolerance is established in a relatively short time, which requires increasing amounts of alcohol to obtain the same drowsiness.
What is considered a typical sleep pattern?
Sleep is not uniform but is made up throughout the night into a pattern of several sleep cycles.
A typical night might contain four to six such cycles, each lasting from sixty to ninety minutes, though lengths vary.
There usually are four sleep stages within each cycle, of which three are non-rapid eye movement, known as N1, N2 and N3, and the fourth is rapid eye movement, known as REM.
However, each stage displays different brain activity:
- N1 – the ‘dozing off’ phase, from which it is easy to wake. Brain activity starts to slow. Duration about five minutes.
- N2 – a more subdued state including a drop in body temperature, relaxed muscles, slow heart and breathing. Brain activity slows, and eye movement stops. Duration up to twenty-five minutes.
- N3 – deep sleep, from which it is harder to wake. The body slows and relaxes further. Brain activity becomes slow, known as delta waves. This stage is critical for restorative functions, allowing body recovery, healing and growth. It may also contribute to enhanced creativity and memory. Duration up to forty minutes.
- REM – brain activity increases towards wakefulness levels. The body experiences temporary muscle paralysis (atonia) except for the eye and breathing muscles. This is the period of the most vivid dreams and is also an important time for nurturing cognitive functions such as memory, learning and creativity. Duration increases through the night from a few minutes to one hour in the later sleep stages.
Each sleep cycle will contain these four stages. Failure to obtain enough deep sleep and REM sleep may produce adverse consequences for cognitive abilities and emotional and physical health.
Factors affecting sleep stages
Factors that may affect sleep cycles include a person’s age, recent sleep history and consumption of alcohol and other sedatives and other disorders.
- Age – Babies engage in extended REM sleep but are nearly adapted to an adult pattern by the age of five. Older adults tend to spend less time in the REM stage.
- Sleep history – disrupted sleep over a period will result in abnormal sleep cycles that take time to correct. As discussed further below, alcohol and other sedatives can disrupt sleep cycles, especially in the deep sleep and REM stages.
- Other disorders – sleep disorders, such as sleep apnea and other physical conditions – restless limbs or continence issues, can result in multiple awakenings that disrupt the sleep cycles.
Causes of insomnia
Recurrent insomnia is often the result of stress, life events or a lifestyle that is not conducive to regular rest periods.
- Stress – worry over all kinds of concerns such as work, family and finances can keep one awake, sometimes leading to a self-defeating spiral where sleep loss translates into the loss of competence in coping with the stress itself.
- Life events – any significant adverse event can lead to periods of insomnia. There may be a need for professional help where trauma is a factor.
- Unhealthy lifestyle – excessive work and travel schedules, poor eating habits and late nights can disrupt sleep patterns, sometimes over long periods.
Feeling overwhelmed and turning to alcohol to cope? Take a look at the admissions process.
How does alcohol affect the brain and central nervous system?
Alcohol acts as a depressant on the central nervous system that causes brain activities to slow down.
Intake of large amounts of alcohol before sleep leads to initial drowsiness followed by changes in sleep patterns early in the process when blood alcohol levels are high.
Heavy drinkers may fall into deep sleep sooner, but later sleep stages are commonly disrupted and become less vital.
Later sleep cycles show a reduction in lower delta wave sleep and more rapid-eye-movement sleep than average.
Overall, the outcome is to leave the sleeper feeling poorly rested and insufficiently refreshed.
Heavy drinkers who develop chronic tiredness due to poor sleep patterns often learn to self-medicate – they will consume more immediately before retiring simply to fall asleep.
However, the sleep will not last long and will likely be followed by insomnia.
How does alcohol impact sleep?
Alcohol directly influences the body’s circadian rhythms – those powerful responses of our internal biological clock that regulate and synchronise the cycles of our metabolism, sex drive and sleep patterns.
Alcohol disrupts these rhythms (other factors such as air travel through time zones do the same).
It also disrupts how the body metabolises substances such as alcohol – a double disruption.
Heavy and excessive drinking is always likely to disrupt sleep, but even low alcohol intake (two servings a day) will have some adverse effects.
A 2018 study of sleep quality among people who consumed alcohol at several different levels showed a negative impact at all levels:
- Low – fewer than two servings per day (M) or one (F) – 9.3% decreased sleep quality.
- Moderate – two servings per day (M) or one (F) – 24% decreased sleep quality
- High – more than two servings per day (M) or one (F) – 39.2% decreased sleep quality.
Large amounts of alcohol are likely to cause more disruption to sleep, but even small amounts can lead to restless nights and insomnia.
Research shows that consuming alcohol increases the risk of sleep apnea by twenty-five percent.
How does alcohol affect people who already have insomnia?
People who already have insomnia are unlikely to benefit from alcohol use.
They will be better advised to address the root causes of their insomnia by focusing on removing stress in their lives, adopting a healthier lifestyle and seeking professional help in addressing relevant issues such as trauma or co-morbid medical conditions.
Any alcohol user experiencing sleep disruption should cease drinking alcohol at least four hours before retiring to sleep.
Alcohol and insomnia can be treated as co-occurring disorders.
Any alcoholism treatment involves lifestyle change achieved through self-discovery to identify maladaptive attitudes and behaviours.
Any co-occurring insomnia can be addressed at the same time in the following ways:
- Sleep hygiene – bedroom and bedding, lighting and heating, use of electronic devices.
- Diet – regulating intake and quality of food and liquids, eliminating alcohol and caffeine.
- Structure – following a regular timetable of work, recreation and rest.
- Wellbeing through meditation, exercise and healthy habits.
- Peace of mind by gaining a sober recovery while addressing underlying issues such as trauma with professional help.
Most people who undertake a rehabilitation course from addiction present with a degree of co-occurring sleep disorder.
The great majority find that insomnia problems greatly decrease or disappear altogether within a few weeks, provided they continue to live sober and structured lives.
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