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10 popular sleep myths debunked for World Sleep Day — and the real science behind restful nights
It's World Sleep Day! Quality sleep is the cornerstone of overall well-being, and many of us are willing to try almost anything to improve it.
From mouth taping to white noise machines, the sleep industry - worth billions of dollars - offers countless products and techniques promising better rest. However, not all of these methods are backed by science.
In fact, some widely accepted sleep habits may be doing more harm than good. Take the belief that alcohol helps induce restful sleep or that a warm bedroom is ideal for slumber - both are misconceptions.
To separate fact from fiction this Sleep Awareness Week 2025, we consulted two sleep experts, Heather Darwell-Smith, an accredited psychotherapist who specializes in sleep, and Maryanne Taylor, a certified sleep consultant and founder of the Sleep Works, to debunk common sleep myths and explore what truly leads to restorative rest.
10 popular sleep myths debunked
1. You sleep better in a warm bedroom
“The idea that you sleep better in a warm room is a common misconception,” says psychotherapist Heather Darwell-Smith. “In reality, a cooler sleeping environment is far better for high-quality sleep. Research suggests the ideal bedroom temperature is between 16–18°C (60–65°F).”
This is because sleep is regulated by the body’s core temperature, which naturally drops in the evening as part of the circadian rhythm.
“Sleeping in a warm room can interfere with this cooling process, making it harder to fall and stay asleep,” Heather explains.
“A study found that elevated bedroom temperatures disrupt slow-wave sleep (deep sleep) and REM sleep, both essential for cognitive function and physical recovery,” she adds.
Aside from this, “overheating at night has also been linked to increased night wakings, restlessness, and poor sleep efficiency,” Heather says.
“So rather than a warm room promoting better sleep, a cooler environment helps the body maintain its natural sleep cycle and achieve deeper, more restorative rest.”
2. The weekends are for lie ins
Many believe that skimping on sleep during weekdays and compensating on weekends is harmless. However, experts warn that this pattern can disrupt your body's internal clock and impair cognitive functions, and instead a regular sleep schedule even on the weekends is best.
In fact, a study found that after limiting sleep and trying to catch up on sleep, examined groups snacked more at night, gained weight, and showed signs of deteriorating metabolic health, compared to the start of the study.
So, while you may feel that your weekend lie-ins give you some r&r, it’s really a sleep debt you can’t pay back. Having a solid sleep hygiene routine can ensure you are regularly getting enough sleep for your body and mind to be at its best during the day.
3. Falling asleep fast is good
Your sleep onset latency (SOL) is the amount of time it takes you to go from fully awake to being asleep, and it can depend on a lot of things.
And, we hate to tell you this, but it isn’t actually a good sign if you fall asleep within seconds of your head hitting the pillow. Experts estimate that 1 out of 3 adults in the United States suffer from limited sleep, or sleep deprivation.
Instead, a healthy sleep latency is around 10-20 minutes.
If you find yourself falling asleep quickly, it’s likely you may be suffering from sleep deprivation, and your body is desperately trying to claw back some rest. Health issues like sleep apnea and narcolepsy can cause excessive daytime sleepiness, so if you’re falling asleep during the day, it may be time to reevaluate your idea of ‘good’ sleep.
Feel this might apply to you? Then contact your doctor to see if there are any underlying sleep disorders you may be unknowingly experiencing, especially if you find that after falling asleep quickly you still wake up tired.
4. Alcohol helps you sleep
“While alcohol can make you feel drowsy, it does not improve sleep quality,” explains Heather. “In fact, it does the opposite. Alcohol acts as a sedative, reducing sleep latency (the time it takes to fall asleep), but it significantly disrupts sleep architecture later in the night,” she adds.
While alcohol can make you feel drowsy, it does not improve sleep quality
This is why, despite getting over 8 hours of sleep after drinking, you’ll still feel groggy and fatigued the next day.
“Research shows that alcohol reduces REM sleep by increasing wakefulness in the second half of the night,” Heather explains, saying “Alcohol suppresses deep sleep early on but then causes frequent awakenings and lighter sleep.”
Aside from this, “alcohol can worsen sleep disorders, as alcohol relaxes the muscles in the throat, increasing the risk of snoring and sleep apnoea, leading to poorer oxygenation and disrupted sleep cycles.”
5. All adults need 8 hours of sleep
“The idea that everyone must get around 8 hours a night to have slept well is not just a bit of a myth but can be somewhat anxiety inducing for people who feel concerned about their sleep,” explains Maryanne Taylor.
“While 8 hours is a reasonable overall average, the reality is that there isn’t a one-size-fits-all when it comes to sleep needs and it can vary quite significantly from person to person,” she adds.
Most people will benefit from 7-9 hours of sleep a night. But Maryanne says “Some people are ‘long sleepers’ and function better on 8 hours +, while others are ‘short sleepers’ and do fine on 6-7 hours.”
Maryanne continues, saying: “What matters more than the exact number is the quality of sleep and how a person manages their day, and if they can do what they need and want to do on most days.”
6. You shouldn’t wake up during the night
Worrying over waking up during the night? Don’t stress. It’s normal to wake during the night. In fact, scientists believe that we developed to wake like this to check that we were safe in our caves and not going to be attacked by predators.
Think of it this way: our sleep moves through cycles. So, the first part of the night will normally contain more deep sleep and the early hours of the morning will be spent in more REM sleep. Therefore, we’re more than likely to wake up during the night as we transition between deep and light sleep cycles.
Focus more on the quality of your sleep and how rested you feel in the morning rather than if you woke up or not – that holds the key to unlocking your best slumber.
7. The brain isn’t active at night
Sleep is often referred to as ‘powering down’ for the day – but that doesn’t mean your brain shuts off.
“The idea that the brain “shuts off” during sleep is a myth – it remains highly active, engaging in essential functions that support memory, learning, and overall health,” Heather explains.
“In fact, it has been said that ‘sleep is by the brain, for the brain’,” she adds. “For example, Slow-Wave Sleep (SWS) is deep sleep for restoration as the brain clears out metabolic waste, including beta-amyloid, a protein linked to Alzheimer’s disease.This phase is crucial for cell repair, immune function, and physical recovery.”
8. Cheese gives you nightmares
A popular old wives tale, eating cheese before bed doesn’t actually give you nightmares. “There’s no solid evidence to suggest that eating cheese before bed directly leads to bad dreams,” Maryanne says.
“Cheese is high in fat and protein, which takes longer to digest so eating it, or in fact other rich, fatty or spicy foods might lead to digestive discomfort which can disrupt sleep,” she explains.
This fragmented sleep can lead to more vivid or memorable dreams, which some people might interpret as nightmares.
“Cheese specifically will not give you nightmares – but if you find eating a heavy, rich meal before bed gives you vivid dreams, it may be better to eat earlier in the evening or opt for a lighter meal before bed,” Maryanne advises.
9. A plush mattress is the best kind
It might sound like the truth, but a plush soft mattress you sink into sadly won’t guarantee a good night’s kip and can even lead to discomfort.
For example, a super soft mattress can encourage the body to sink into the mattress, leading to poor spinal alignment and restless sleep.
If you suffer from sleep apnea, a plush mattress can worsen your condition by causing your airway to close further.
Looking for your ideal mattress and unsure where to start? Consider your body type and your sleeping position. Back and stomach sleepers of average weight will need a medium firm to firm mattress, whereas side sleepers will need something a little softer.
10. You can catch up on sleep the next night
“Unfortunately you cannot ‘catch up’ on sleep. You can’t bank sleep at the weekend and put it towards lost sleep hours during the week,” says Maryanne.
“When we don’t get enough sleep, we build up a sleep debt, which can impact mood, memory, focus, and even immunity,” she explains.
When we don’t get enough sleep, we build up a sleep debt, which can impact mood, memory, focus, and even immunity
While you might feel some temporary relief after having a nice long lie in, Maryanne warns that it can throw off your internal body clock, “making it harder to fall asleep at the right time when you go back to your usual routine. It’s a bit like giving yourself jet lag every time you try to ‘catch up.’”
Instead, Maryanne says consistency is key. “Sticking to a regular sleep schedule, or as close as possible, even on weekends, will help to regulate the body clock, making it easier to fall asleep, stay asleep, and wake up feeling more refreshed.”
