25 Things You Need to Know About Sleep Right Now

Will a lack of shut-eye make you fat? Do white-noise machines cause deafness? Are night owls wealthier than early birds? Wake up to the secrets of slumber.

25 Things You Need to Know About Sleep Right Now

1. Had a terrible sleep? Have someone lie to you
It’s the wake-up mind trick. A paper published in 2014 in the Journal of Experimental Psychology showed that when students were told they’d had a good night’s sleep, even if they hadn’t, they performed better on tests than those who were advised their slumber was truly subpar.

2. Sleep machines won’t damage your hearing – or your baby’s
A controversial study from Toronto’s Hospital for Sick Children released last year identified white-noise machines as a possible cause for hearing loss in infants. And while results showed potential for damage, the risk came from using the machine at loud ­volumes and for longer periods and in closer proximity than recommended. Nothing dialling down the volume and leaving a wide berth can’t fix.

3. Why any sleep is better than no sleep (no matter how you feel when you wake up)
While the idea of pulling an all-nighter to ensure you make that 4am flight or ace that early-morning presentation might be tempting, take a nap instead. A study of plane pilots by NASA reveals that catching any shut-eye at all, even as short as 26 minutes, will boost your cognitive function when you wake.

The best naps are either short or long

4. A “power nap” (10-20 minutes) can restore your alertness without accompanying feelings of “sleep inertia”, aka post-nap grogginess.

5. A 90- to 120-minute nap also avoids sleep inertia and helps with mental processing. This allows a full cycle of sleep, during which the brain moves through slow-wave deep sleep and into REM-stage sleep, associated with dreaming.

Evening countdown

6. Scientists say you should stop looking at TVs, computers, smartphones and tablets for at least two hours before you go to sleep. The blue light – light that is richer in short, or “blue”, wavelengths – emitted by most screens suppresses the secretion of melatonin, which will shift your circadian rhythm and keep you awake.

7. Turn down the heat. Most people’s bedrooms are kept too warm for the body to sleep well, says Dr Atul Khullar, a psychiatrist and sleep expert. Keep your room as cool as possible without being uncomfortable – between 18.5 and 21°C.

8. Keep the tech out of the bedroom. Make it into a calm sanctuary dedicated to sleep. Swap your screens for a paper book or magazine before bed.

9. Buy an alarm clock. Although your smartphone’s alarm will do the trick, chances are you’ll scroll through email, read the news or check an app when you should be focused on dozing off. “Alarm clocks have been around for 150 years and cost $9. Use one,” says Khullar.

10. Have a light snack. Avoid proteins or fatty foods one or two hours before bed (the burst of energy they provide will keep you up), and opt instead for a small serving of a complex carbohydrate like cereal.

11. Sleep and obesity arelocked in a vicious cycle
22% is the number of extra kilojoules consumed by men who slept for four hours versus eight hours in a 2010 study published in The American Journal of Clinical Nutrition. Neither the well-slept nor under-slept participants said they felt hungrier or enjoyed the foods more, yet the tired group consumed substantially more kilojoules during subsequent meals.

12. 45 minutes is the amount of time each member of a group of 25 insomniacs spent listening to soothing music before bedtime every night. Their REM sleep significantly improved compared to 25 matched insomniacs who went without.

13. Scientists can see your dreams
Using MRI and an algorithm, doctors in Japan inferred what their test subjects were dreaming about from their brainwaves. “Dreaming has been thought to be a private experience, accessible only to the person experiencing the dream,” says Yukiyasu Kamitani, of Kyoto’s ATR Computational Neuroscience Laboratories. But his lab has taken a glimpse behind the veil by assembling a database of commonly dreamt images (cars, buildings, men, women, food and even furniture) and correlating them with three participants’ brain activities, testing them more than 200 times each. With this data, Kamitani was able to guess what was dreamt 60% of the time. It seems there’s no escape from our work and personal stresses: most dreams were about the office or the family.

14. Without sleep your brain plays tricks
In 2014, researchers at the University of Bonn in Germany discovered that people who hadn’t slept for 24 hours experienced schizophrenia-like symptoms, including pronounced attention deficits, hallucinations and a skewed sense of time and smell.

15. Insomnia isn’t about falling asleep
Or, at least, not only; indicators of insomnia also include waking up too early, not feeling rested in the morning, irritability, depression, headaches and gastrointestinal distress.

16. 30% of adults are estimated to exhibit signs of insomnia, including waking up 30 minutes earlier than they’d planned, being up for longer than 30-minute stretches during the night or taking longer than half an hour to fall asleep.

17. Sleep learning is possible
If the chords of “Sweet Caroline” continue to elude you, adjust your earphones and take a nap. Scientists at Illinois’s Northwestern University have discovered that listening to a melody in slow-wave sleep helps cement it in your memory and you’ll play the tune better. The same principles apply to foreign languages, according to research from two Swiss universities. Review your new vocabulary before you sleep, play audio of the words you have been learning for 90 minutes while indulging in a little shut-eye, and you can anticipate better recall upon waking.

Men and women aren’t created equal

18. Men tend to have worse-quality sleep than women but are less likely to complain about it. Good sleep is linked with good health, so it’s worth making a fuss to improve yours.

19. Insomnia disproportionately affects women; complex hormonal cycles play a role. Doctors may prescribe sleeping pills as a short-term solution, but lifestyle changes, like getting more exercise (especially in the morning rather than at night), can make a big difference.

20. Nix the nightcap: Alcohol doesn’t help you sleep
Booze may ease the slide into slumber, but researchers have found it promotes wakefulness later in the night, not to mention restless leg syndrome, night sweats and trips to the bathroom.

21. Is your tongue larger than average?
Obese men with obstructive sleep apnoea were likelier to have larger tongues than those who slept normally, according to 2014 research. They also had more fat at the base of their tongues, leading researchers to hypothesise the appendage was blocking sufferers’ airways.

22. Want to promote sleep? Don’t count sheep
Rather than audit a fictional herd of woolly mammals (something active), try picturing a restful scene (something passive). If you haven’t fallen asleep within 15 to 20 minutes, move to another room, take up a quiet activity, such as reading, then try again.

23. Couples who sleep (really, really closely) together stay together
A British psychologist who recently asked 1000 people at the Edinburgh International Science Festival to describe their preferred sleep positions and the quality of their relationships found this correlation: the further apart couples slept, the lower they rated their relationships. 94% of couples who spent the night in contact were happy with their relationships, versus 86% of couples who spent the night less than 2.5cm apart and 66% who slept more than 75cm apart.

24. Spooning: uncomfortable but popular
31% of couples from the same study (see No, 23) slept facing the same direction. Spooning was beaten out only by the roomier back to back (42% of couples). Face to face was the position of choice for 4% of partners.

25. Caffeine keeps you awake by being a talented mimic
Drowsiness occurs when a molecule in your body called adenosine binds to receptors in the brain, slowing down neural activity. Caffeine molecules look just like adenosine and can therefore bind to those same receptors, blocking off adenosine – and sleep. Instead, you get sped-up brain activity and a flood of adrenalin.


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