From nightcaps to nightmares: the many ways alcohol disrupts your sleep

With the seasonal festivities already in full swing, some are already fantasizing about a dry January full of early nights.

But Dr. Alex George, public health advocate and former Love Island contestant, revealed last week in a video on his YouTube channel that a sober night’s sleep isn’t necessarily all it’s cracked up to be — at least not in the early days of sobriety.

Two years after George gave up alcohol, he revealed that his sleep “got worse for about eight weeks before it got better.”

For the first two months, he said, he had trouble falling asleep, felt tired when he woke up and had “crazy dreams.”

His comments provide insight into the often mysterious and misunderstood influence of alcohol on sleep. Although some people associate a nightcap with a good night’s sleep, it’s important to remember that “sedation is different from sleep,” according to Professor Russell Fosterhead of the Sleep and Circadian Neuroscience Institute at the University of Oxford.

One of the main issues is how booze disrupts our nocturnal cycles, or what some people call ours ‘sleep homeostasis’.

Normally sleep takes place in five phases between waking and rapid eye movements (REM). In between are stages of increasing depth, N1, N2 and N3 (where N stands for non-REM). N3 is also called slow wave sleep (SWS or deep sleep) and makes up about 80% of our sleep.

A typical night’s sleep, if we can get it, consists of four to five cycles through these five phases. Importantly, each of these phases is associated with different biological processes, all of which are essential to reaping the full benefits of rest.

As Professor Foster says, REM sleep is ‘the period when you have your most complex and vivid dreams. It is also associated with emotional processing; it is the body trying to understand a complicated world.”

Multiple studies have shown that alcohol, when consumed in moderate or large amounts, causes an overall reduction in total REM sleep, which in turn can lead to forgetfulness, anxiety and concentration problems.

Alcohol also causes an increase in SWS in the first half of the night, according to the study majority of studieswhich initially leads to a deeper sleep. This may sound like a good thing, but it can lead to disruptions as the night progresses, due to something called “homeostatic recovery.”

If you lose certain elements of the cycle at some point during the night, your body and brain will try to make up for it at another time.

And because alcohol can increase SWS in the first half of the night, the brain spends more time in light, non-REM sleep the rest of the night, from which you are much more likely to wake up.

“The other issue that is often ignored is alcohol’s role in obstructive sleep apnea (OSA) and snoring,” says Foster. “What alcohol does is relax the muscles of the throat and neck, which means you’re much more likely to snore and worsen OSA.”

All this means that even if you spend longer in bed after a drink or two, sleep quality can be significantly reduced. But what happens when it’s more than a drink or two, and it happens regularly?

Not surprisingly, the long-term effects of alcohol and alcohol dependence on our sleep are largely considered to be an accumulation of many of the short-term effects above. The other is insomnia.

A Study from 2018 found that two-thirds of alcohol-dependent patients suffered from insomnia (compared to one-third of the healthy adult Western population).

Exactly why this happens is still unclear, but prolonged sleep disruption, poor sleep hygiene and increased tolerance to the sedative effects of alcohol likely play a role.

What is somewhat clearer is the important role that neurotransmitters – signaling molecules in the brain – play in alcohol’s effects on sleep, regardless of the level of intake.

“What we do know is that alcohol disrupts the body’s neurotransmitter systems and changes them during the sleep cycle and during sleep,” says Foster.

Importantly, although these changes are often reversible, it can take some time for our neurotransmitters to recalibrate. This is why it can take up to eight weeks to abstain from alcohol, just like Dr. George – possibly longer in others – before sleep is fully restored.

This period can include insomnia and, tragically for those who try to abstain, persistent sleep problems, which can often be a form of sleep reason for relapse.

In his recent videomentioned Dr. George also had ‘crazy dreams’ after sobriety. There is also a scientific explanation for this: the “REM rebound effect”.

Similar to homeostatic recovery, the brain compensates when REM sleep is depleted for any reason. Because dreams are most likely to occur during REM sleep, studies show that those who have given up alcohol may have more vivid dreams. This effect probably occurs on a smaller scale after a drink or two.

But quantity and timing are crucial.

Professor Foster estimates that one glass of wine is likely to reduce sleep quality “by about 10 percent” – but once you start feeling tipsy, “it will be 40 percent”. He also says that these percentages will be drastically affected by how close to bedtime your drinks are consumed; the closer to bedtime, the worse they are.

So if you’re looking for a good night’s sleep, too many nightcaps isn’t the best choice.