As the UK endures another scorching heatwave, many blame soaring temperatures for sleepless nights. But pharmacist and lead developer at health and recovery brand Humans Against, Ali Alshamari, reveals a surprising culprit: alcohol. “While hot nights can make it harder to drift off, alcohol is one of the biggest yet most overlooked disruptors of healthy sleep,” Alshamari explains. “Even one or two drinks can have a bigger impact than you realise, leaving you groggy, irritable, and mentally foggy the next day.”
Alcohol’s effects on sleep are far-reaching, impacting everything from brain activity to hydration levels. Alshamari outlines how alcohol sabotages restful slumber, offering practical solutions to mitigate its harm. Below are the key ways alcohol disrupts your sleep cycle, based on verified insights from health experts and sleep research.
Alcohol’s impact on sleep
- It fragments your sleep: “Alcohol’s initial sedative effect wears off quickly. As your body processes it, brain activity increases, leading to frequent wake-ups during the night and fewer restorative deep sleep stages,” Alshamari notes. This disruption reduces the quality of rest, leaving you less refreshed.
- It cuts down your REM sleep: “Rapid eye movement (REM) sleep is crucial for memory, mood, and mental clarity. Alcohol drastically reduces the amount you get, leaving you more forgetful and less focused the next day,” he explains. Studies from the National Institute for Health and Care Research confirm alcohol suppresses REM sleep, impairing cognitive function.
- It dehydrates you: “Alcohol is a diuretic, meaning more trips to the bathroom and more lost fluids. Dehydration can cause headaches, dry mouth, and further sleep disruption,” Alshamari says. Research from the Sleep Foundation highlights dehydration as a key factor in alcohol-related sleep issues.
- It worsens snoring and sleep apnoea: “Alcohol relaxes the muscles in your throat, which can increase snoring and trigger dangerous breathing interruptions during sleep,” he warns. The British Snoring and Sleep Apnoea Association notes alcohol exacerbates sleep apnea symptoms, posing health risks.
- It disrupts your body clock: “By throwing off your circadian rhythm, alcohol makes it harder to fall asleep and wake at your usual time, contributing to ongoing fatigue,” Alshamari states. NHS guidance underscores the importance of a stable circadian rhythm for consistent sleep patterns.
- It can trigger vivid dreams and insomnia: “As alcohol wears off, the body can experience a ‘REM rebound’, causing unusually vivid or disturbed dreams that disrupt rest. Over time, regular drinking can also build tolerance to alcohol’s sedative effects, creating a cycle of needing more to fall asleep and ultimately worsening insomnia,” he adds. The Sleep Council reports that REM rebound is a common issue among regular drinkers.
How to improve sleep quality
Alshamari provides actionable advice to improve sleep quality after drinking.
- Hydrate before bed: Drink plenty of water to help flush out the alcohol and reduce dehydration.
- Keep it light: Avoid heavy meals close to bedtime, opting instead for something easily digestible like a light snack.
- Stick to a routine: Go to bed and wake up at the same time each day to help support and regulate your body clock.
- Wind down screen-free: Swap scrolling for calming activities like reading or music to signal bedtime to your brain.
- Know your limits: Reducing alcohol intake is the single best way to minimise its impact on sleep.
Alshamari explains alcohol’s neurological impact: “Alcohol is a depressant that slows down brain activity by affecting neurotransmitters such as gamma-aminobutyric acid (GABA) and glutamate. GABA produces a calming effect, while glutamate triggers excitatory signals. Alcohol enhances GABA’s calming influence and suppresses glutamate’s activity, creating a temporary sedative effect that makes you feel drowsy but this effect is short-lived, which can disrupt your sleep later on.”
While heatwaves exacerbate sleep struggles, alcohol’s role is often underestimated. “While hot weather can make your bedroom feel like an oven, alcohol is often the real culprit behind waking up restless at 3am,” Alshamari concludes. By staying hydrated, maintaining a consistent bedtime, and cutting back on alcohol, especially late at night, you can significantly improve your sleep quality, even during the hottest summer nights.