For many people, a few alcoholic drinks might feel like a personal sleep tonic and be an easy way for them to nod off. Night cap? Sure, why not.

The truth is, the relationship between sleep and alcohol is a poor one.

Poor sleep quality, increased risk of sleep apnoea and messing with your circadian rhythm (sleep chemicals) are just a few of the ways sleep is impacted negatively by alcohol.

Between 1985 and 2015, 21 studies across the world concluded that alcohol increased the risk of sleep apnoea by 25%. Sleep apnoea occurs when the walls of your throat come together while you sleep, blocking off your airway.

It affects 1 in 4 Australian men and has a host of serious consequences on your health. Alcohol relaxes the muscles in your throat that can narrow the airway, increasing the likelihood of snoring and sleep apnoea.

Sleep is broken down into four stages, three of these are NREM non-rapid eye movement) or deep sleep and one is REM (rapid eye movement) sleep. REM sleep is shorter in cycle but known to be the stage of sleep where we dream and is considered essential to cognitive functions such as memory, learning and creativity.

Alcohol is recognised to disrupt normal sleep patterns, often decreasing the REM sleep and increasing sleep disturbance. Since a landmark study in 1939 the relationship between sleep stages and alcohol have been studied extensively. The conclusions from one study of 4000 people were that moderate alcohol consumption negatively impacted the restorative quality of sleep by 24% and high consumption reducing restorative sleep by 39%.

Circadian rhythms are your internal body clock that helps regulate the sleep-wake cycle. Alcohol boosts the level of adenosine which signals the body to become drowsy. However, as it’s an unnatural response, once it wears off, people can become restless and wake easier in the night as the alcohol has interrupted the body clock’s ability to synchronise itself.