Would you go to work drunk? Didn't think so. But one sleep doctor, Harvard's Josna Adusumilli, recently said some of us might as well do exactly that. She claims many people go to the office on as little as six hours' sleep each night - which, when done regularly, has the same detrimental effect on mental and physical performance as turning up three sheets to the wind.
Medical experts all agree that sleep is essential, for health and sanity - which might not sound like good news if, like many of us, you live in a world where 'I'm tired' is practically the new 'hello'. In an this week, , the director of the Center for Human Sleep Science at the University of California, Berkeley, even said that there is evidence that lack of sleep can actually reduce your life expectancy. He has found that it's linked to an increased risk of cancer, heart attacks and Alzheimer’s amongst other things.
As a result it really is more important than ever to take your sleep seriously. If you've forgotten how to sleep well, here's what you need to know to get back on track.
Do you really need 8 hours' sleep?
"Most people need somewhere between seven to nine hours," says Dr Sophie Bostock, health psychologist from sleep app creators . Within that, exactly how much, or how well we sleep, can be determined by many different factors; it's genetic (and about 1% of the population actually possess genes that mean they can get away with as little as four hours). Women tend to sleep less effectively than men, and need about an extra 20 minutes a day, and as we age, our quality of sleep improves so we actually need less to feel restored. So, how do you know how much is right for you? There's no definitive test, but the five questions below will teach you how to read your body's signals.
Do you fall asleep as soon as your head hits the pillow?
Actually, it should take about 15 minutes after getting into bed to drop off. "If you fall asleep quicker, you're sleep deprived; if you take longer than 30 minutes, you're sleeping more than you need - or something like stress is possibly interfering," says Dr Bostock.
Do you need an alarm clock to wake you up?
Unless you have to get up at an unsociable hour like 4am, Dr Bostock says a sign of sleeping well is that you wake naturally before your alarm. Repeatedly hitting snooze says you're not getting enough sleep.
Do you sleep more than one hour extra at weekends?
"Saying 'yes' is a sign you're collecting a sleep debt in the week that your body is trying to make up for. When you're sleeping the right amount for you, you should sleep the same number of hours all week," says neurologist Dr Guy Leschziner from the Sleep Centre at London Bridge Hospital.
How do you feel at 11am?
The answer should be alert and energised, as this is the point in your circadian rhythm [a 24-hour cycle that tells your body when to sleep] when you should be most awake. "If you're tired at this point in the day, you're definitely not getting enough sleep - or something else is draining your energy," says sleep specialist Dr Neil Stanley.
If you do feel tired, are you snappy, overly tearful, argumentative or more easily stressed?
Tiredness can be caused by lack of sleep or low energy, "but low energy doesn't tend to be associated with an impact on emotional function," says Dr Stanley. "That's a sign that you're lacking sleep."
How to use the results
"Be your own scientist and test your theories," says Dr Bostock. "If you think you might need more - or less - sleep, adjust things for a few weeks, then do the quiz again and see what improves." But remember, the best results aren't instant. "It takes a while to change your sleep clock," says Dr Suveer Singh, sleep specialist and consultant in respiratory medicine at London's Bupa Cromwell Hospital. "To move things by an hour or more, first bring your bedtime forward or back 15-30 minutes for a few nights and let your body adapt, then shift again if needed."
Sleep saviours that really work. Forget lavender pillow sprays, try these instead...
- Take omega-3. Research from the University of Oxford found it improves sleep. "DHA in omega-3 fats might lower anxiety or help with the release of melatonin - the hormone that signals sleep," says the study's author, Professor Paul Montgomery.
- Get as much natural daylight as you can. Research found that those who get the most during the day (even through a window) sleep best at night.
- Create a sleep signal. According to Harley Street hypnotherapist Pat Duckworth, touching your ear, stroking your cheek, putting your thumb and finger together - any easy move - when you're sleepy lights up a neural pathway in the brain that you can use to stimulate sleep when it's not coming naturally. "It's called anchoring. You'll need to do it several times so the two become linked. Then, pressing that point when you can't sleep will light up the pathway for sleepiness and you'll drop off," she says.
- Listen to . That's the eight-hour 'lullaby' composer Max Richter wrote with advice from neuroscientist David Eagleman. He's hoping it will help people fall asleep and keep them snoozing all night, calling it "an eight-hour place to rest".
- Drink ZenBev. This is made from pumpkin seeds, "rich in the amino acid tryptophan in a form the body can convert into sleep hormone melatonin," says creator Dr Craig Hudson. In a trial, insomniacs said it cut night-time waking by 39%. £25.99, zenbev.com
- Wear H7 Insomnia Control. This band massages the H7 acupressure point on the wrist, which in Chinese medicine aids sleep. In trials at Rome's La Sapienza University, 72% of patients found it helped. £9.90 from independent pharmacies.
A nightcap will help you sleep. Yes, an alcoholic tipple might knock you out, but research from The London Sleep Centre shows it messes with REM sleep. Lack of REM is linked to anxiety, irritability and higher appetite.
"You need to make up sleep. If one night you lose four hours, you might wonder how you'll catch up. But after a bad night, your body goes into a deeper sleep the next night - so you only need about a third of the sleep you lost," says Dr Bostock.
Exercise before bed keeps you awake. Not if you work hard, says a study from Basel University. Students did sport for 65-90 minutes before bed; those who worked the hardest fell asleep fastest, slept more deeply and woke less in the night.
What's new in sleep?
Always wake up in the middle of the night? You could just be a segmented sleeper. "This is where people sleep in two long blocks separated by about 30 minutes of wakefulness," says Dr Richard Wiseman, author of Night School. If this happens, but you drop off again naturally and you score OK on our 'Are you sleeping enough?' test, don't worry when you do wake up - stressing is what turns waking up naturally into insomnia.
If you don't sleep well, focusing positively on the hours you did get (rather than worrying about those you missed) actually makes you perform better the next day, says research from Colorado College.
Are you depressed or just very tired?
It's long been known that having problems with sleep - specifically waking up super early, or sleeping a lot during the day - are signs of depression, but it's more complicated than that. "We now know that poor sleep isn't just a symptom of depression or anxiety, but it can also be a trigger," says Dr Bostock. "Treat poor sleep, and you can help improve mental health symptoms, too."
In a recent NHS-backed trial, 65% of patients using the app and online-based programme Sleepio to tackle sleep problems also recovered from symptoms of depression and anxiety. And research from Binghampton University in New York found that simply going to bed early and extending people's sleep time helped reduce negative thinking.
"Improving sleep helps you cope better with lifestyle factors like stress that aggravate mental health problems," says Dr Bostock. You must see your doctor for severe depression, but if you have a mild or temporary case of the blues, try improving your sleep and see what happens. sleepio.com
How to sleep better if you...
Have a social media habit
The blue light from smartphones interferes with sleep, as it prevents the full release of melatonin. But the Mayo Clinic found that if you keep your device at least 35cm away from your face and dim the brightness, it doesn't have this effect. And download f.lux, which adjusts the light level of your screen to fit the time of day you're using it.
Share a bed with a snorer
Get them to do this daily: push the tip of their tongue against the roof of their mouth, then slide it backwards; suck it up against the roof of the mouth, then force it against the floor of the mouth, keeping the tip in with the teeth; finally, say 'A' while trying to lift the uvula (that dangly thing that hangs down the back of the throat) only with their muscles. In trials at Brazil's University of São Paulo, it reduced snoring by 36%.
Stress a lot
Try the 4-7-8 breathing technique by US health guru Andrew Weil, who claims it can help you fall asleep in as little as a minute. Keep your tongue behind your upper front teeth, breathe in through your nose quietly for a count of four, hold for a count of seven, then exhale through your mouth with a whooshing sound for a count of eight. Repeat until snoozing.
"Spend some time during the day describing your nightmare and imagining a new, improved ending. This simple technique stops nightmares 90% of the time," says Dr Wiseman.
How we beat our sleep demons
"Watching make-up videos"
Elyssa Fagan, 28, PR and digital communications manager from Nottingham
"I struggled to fall asleep, but then I noticed that when I watched vlogs by a make-up artist called Zukreat: Artist of Makeup, her steady voice relaxed me. I started watching them before bed and would drop off. I found out this is called autonomous sensory meridian response (ASMR), which means you experience specific sensations in response to audio or visual stimuli. Lots of people have the same sleepy reaction to different types of video, apparently."
Try it: Search ASMR on YouTube, or visit the channel by .
Lucy Kazmi, 26, support worker from Cardiff
"I found it hard to switch off my brain and when I did get to sleep, the slightest noise would wake me. I wasn't sure about hypnosis, but nothing else had worked so I tried it. Afterwards, I noticed a difference in how quickly I fell asleep. I had three sessions and now listen to a self-hypnosis MP3 when I get into bed. It's very quiet and I barely hear it - but I do drop off."
Try it: See more at and
Hollie Brooks, 26, journalist from London
"A friend found colouring helped her anxiety, so I bought a book. I began to take it to bed and spend half an hour gently colouring and noticed a huge change. It released my anxiety, and stopped me checking social media or emails before nodding off. I've now found using pinks, blues and purples - calming colours - relaxes me even more."
Try it: The Mindfulness Colouring Book by Emma Farrarons (Boxtree, £7.99)
"A bedtime buffer"
Bibi Rodgers, 28, blogger at , from Teesside
"My sleep problems got worse when I got engaged, as I couldn't stop planning at night. I was shattered, so created a 'bedtime buffer', banning wedding, blog or work talk after 9pm as they get me mentally over-excited."
Try it: Work out what triggers the thoughts that stop you sleeping and avoid them two hours before bed. Or download the app , which will nudge you to disconnect at a set time.
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