The myth of the nightcap – the truth about alcohol and sleep
How many times have you heard an evening drink referred to as a “nightcap?” The idea that alcohol consumed in the evening is a persistent, stubborn myth. Alcohol is one of the most commonly used sleep aids, regarded by many people as a helpful boost to a night of rest. But the effects of alcohol on sleep are ultimately sleep disruptive, not sleep promoting.
While alcohol can sometimes have a sedative effect that makes falling asleep easier, the effects of alcohol on sleep over the course of a night tell a different story. Drinking alcohol in too large amounts and too close to bedtime undermines a good night’s rest by altering sleep cycles, encouraging restless sleep, and reducing overall sleep amounts.
An early sedative… sometimes
It’s often the case that drinking alcohol can make you feel sleepy, and can send you initially off to sleep more quickly. Research shows that consuming alcohol occasionally near bedtime shortens sleep onset, the time it takes to fall asleep. Drinking regularly, however, can actually diminish the early-in-the-night sedative effects of alcohol, as the body develops a tolerance to its sedating effects. The more often you drink, the less you’re apt to fall asleep quickly after drinking-unless you drink more.
Alcohol in the body at bedtime alters the sleep cycle, increasing time spent in deep, slow wave sleep early in the night. That may sound like a good thing. But the key to healthy sleep is maintaining the balance of time spent in each sleep cycle. Too much deep sleep can bring greater risk> for sleep-disrupted breathing, including snoring and obstructive sleep apnea.
Problems grow through the night
As the night wears on, the disruptive effects of alcohol become more pronounced. Once the sedative effects of alcohol wear off, you may find your sleep restless and easily interrupted by periods of wakefulness in the late night and early morning. This fragmented sleep in the second half of the night can leave you feeling tired and unrefreshed when you wake for the day. It may also contribute to daytime tiredness, difficulty concentrating, and problems with performance. The lack of refreshing sleep may lead to oversleeping in the morning, which further disrupts sleep-wake cycles.
Sleep fragmentation also interferes with the natural, healthy progression of sleep through different phases throughout the night. Alcohol consumed in the evening near to bedtime shortens the duration of time spent in REM sleep, a stage of sleep that is highly restorative to the brain, and to mental, emotional, and cognitive functions. REM sleep occurs more heavily in the second half of a night’s sleep. A deficit of REM sleep can make you feel tired, sluggish, and un-focused the next day, and may have negative effects on mood.
Sleep-smart drinking tips
To avoid the negative effects of alcohol on sleep, it’s best to curtail drinking within four hours of bedtime. Once it enters the body, alcohol takes several hours to metabolise. This timeframe will give your body time to be largely free of alcohol’s effects before your night of sleep even begins. The amount you drink also makes a difference. A single drink may allow you to fall asleep and even experience a slight increase in deep sleep without disrupting the latter portion of your night’s rest. Several drinks, on the other hand, will be significantly disruptive to sleep quantity and sleep quality.
Mix up your drinking routine
The ritual of a nightly drink is a habit for many people. It can be helpful for sleep to break up that everyday routine, and intersperse a week with a night or two without any alcohol. This gives the body a break, and also helps maintain a sense of what it feels like to sleep without drinking at all. Don’t just abstain from alcohol-in place of an evening drink, choose another nightly ritual that feels good and is sleep friendly. A hot cup of herbal tea, a short walk at twilight, or settling on the couch to watch a film or television program can take the place of an evening drink on the nights you choose not to consume alcohol.
You don’t need to forgo alcohol altogether. Light consumption of alcohol no closer than four hours before bedtime can allow you to enjoy a drink without undermining your sleep.