Parminder Singh, a former managing director at Google, has revealed how just one gin and tonic affected the quality of sleep recorded by his Garmin watch. Writing on the microblogging site, he detailed how the data showed that alcohol impairs the crucial rapid eye movement (REM) stage of sleep, where the brain rests and repairs itself, emotional experiences are processed and memories are consolidated.
Singh posted data showing that alcohol consumption reduced REM sleep to 18 minutes, compared to an hour and four minutes on a normal sleep day. Adults need between seven and nine hours of sleep to wake up feeling refreshed, with the amount of REM sleep that typically occurs later in the sleep cycle varying between an hour and a half and just over two hours.
“Alcohol initially has a sedative effect and helps you fall asleep quickly. But as it is broken down in the body, it disrupts your normal sleep pattern, disrupting both the quality and quantity of sleep,” says Dr Sandeep Bansal, professor, department of ENT and Head and Neck Surgery, PGIMER, Chandigarh.
What is REM sleep and how does alcohol reduce REM sleep?
REM sleep is the most restorative part of the sleep cycle. It stimulates the areas of the brain responsible for learning and memory. When its duration is shortened, you may feel tired even after sleeping through the night.
Drinking alcohol close to bedtime causes frequent waking during the night and fragments your sleep. It can lead to snoring and sleep apnea, and in the long term, it can affect your heart health. Alcohol has a diuretic effect, increasing urine production. This leads to more trips to the bathroom during the night, further disrupting your sleep. Once the effects of alcohol wear off, you may have a rebound effect, waking up later in the night and experiencing insomnia. Even if you manage to sleep through the night after drinking, disrupted sleep quality can lead to fatigue, poor concentration, and irritability the next day.
How does alcohol change your sleep patterns?
Initially, the presence of alcohol in the bloodstream causes a person to fall into a deep sleep. In the brain, alcohol acts on gamma-aminobutyric acid (GABA), a neurotransmitter that inhibits impulses between nerve cells and has a sedative effect. Later at night, when alcohol levels drop, rebound awakening can occur and sleep can become fragmented. Snoring may also increase after drinking alcohol. Alcohol is a muscle relaxant, relaxing the muscles in the upper airway and preventing normal breathing. Drinking alcohol is particularly dangerous for people with obstructive sleep apnea, who wake up multiple times during the night because their airways are temporarily blocked. Your heart rate increases and you may break out into a night sweat as alcohol disrupts your body’s temperature regulation.
How much alcohol does it take to cause sleep problems?
One study found that drinking less than two drinks in men and less than one drink in women reduced sleep quality by 9.3%. Moderate drinking (about two drinks in men and one drink in women) reduced sleep quality by 24%, while heavy drinking (two or more drinks in men and one or more drinks in women) reduced sleep quality by 39.2%.
