The Science of Sleep! (How to Slay at Slumber)


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Put me to bed or lose me forever!

Having trouble falling asleep? Waking up in the middle of the night? Fear not! Science has solutions!


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How much sleep do I actually need each night?

Researchers aren't completely certain why we sleep. Adding to the mystery is that sleep varies wildly among species: Newborn dolphins barely sleep at all. Giraffes sleep in 5-minute bursts throughout the day. Elephants only sleep about two hours a night, while koalas sleep for 22 hours and sea otters hold hands while they doze. (Which isn't really germane, but is insanely cute.)

How much you should sleep varies by biology and age. For most people, however, getting less than 7 hours of sleep per night is one of the strongest predictors of shorter life expectancy. (Insufficient sleep has a bigger impact on longevity than poor diet, social isolation and lack of physical activity. Only smoking is more dangerous.)

Just as important is the timing of your sleep: One study found that students with irregular bedtimes do worse in class than those with consistent sleep schedules, even if everyone gets the same amount of ZZZs. For adults, irregular sleep schedules have been linked to dementia, insulin resistance and mental health problems.

So, how much sleep do you need? The best test is keeping track of how you feel when you wake up: Are you refreshed or tired? Do you nod off in the afternoon? If so, slightly increase your sleep — and, more important, get in bed at the same time each night. (There are lots of devices to help.)

Okay, smart guy, so I need more sleep. But how do I actually do that?

Paradoxically, the most impactful thing you can do is get into the sunlight as soon as you wake up. The key here is to go outside — window glass disrupts the relevant light wavelengths — and start walking. When your optic nerve is exposed to sunlight and you start to move, it resets your circadian clock, which determines cortisol and melatonin levels later in the day and makes nighttime slumber easier. (There are also sunrise alarm clocks if you can't get outside.)

Other things that might help:

Things that definitely don't help (but were once popular):

  • Putting a cold apple on your head, leaving a bowl of sliced onions next to your bed, or applying vinegar-soaked bread loaves to your feet.
  • Cutting a pigeon in half and taping it over your ears. (It also makes side-sleeping messy.)
  • Drinking poisons like nightshade (makes you sleepy! maybe forever!), Mrs. Winslow's Soothing Syrup (which contained a lot of morphine) and quaaludes (which might make you sleepy, but also cause your stereo to start playing funk and your pants to grow bell bottoms).

Finally, if you are really having trouble, you should check out cognitive behavioral therapy for insomnia (CBT-I), which studies say is the best method for overhauling disordered sleep patterns. It's intense, however: It involves strict sleep restrictions, significant diet changes, stimulus control and, usually, working with a therapist to re-design your basic sleep habits. That said, it's the most effective therapy according to the American Academy of Sleep Medicine.

But what about when I'm traveling? Or camping? Or my spouse keeps snoring? Or I really love late-night TV?

For traveling: We often have trouble sleeping on a plane because we're slightly anxious. Airline captain (and therapist) Tom Bunn created the SOAR method to help you ease into dreamland. Also, having the right gear can help. (People on Reddit love this sleep pillow.) In a hotel room, we often suffer from "first-night effect," which is real and measurable, but can be combatted by traveling with things you associate with home. (Like lavender oil. Or morphine.)

For camping (and other challenging sleep settings): Meta-analyses show Progressive Muscle Relaxation can be effective. (Starting with your face, deliberately tense your muscles for five seconds, then let them go slack; work your way down the rest of your body.) There are also practices — meditation, guided breath work, body scanning, self-hypnosis — that can induce deep physical and mental relaxation. (You can find some guides by googling "Non-Sleep Deep Rest" or NSDR.)

For snoring spouses: Consider a 'sleep divorce' by using separate bedrooms. Or, just use separate mattresses side-by-side, also known as the 'Scandinavian sleep arrangement'. (Sometimes it's movement, not sound, that wakes us up.) Or, tell them that the sound of a C-PAP machine makes you feel sexy.

For exercise: All forms of exercise help us sleep, and studies show that Pilates is particularly effective for slumber. However! Timing matters here: Exercising at high intensity four times per week, in sessions of 30 minutes or less, earlier in the day (at least four hours before bed) best improves sleep.

For people who love late-night TV: Trashy TV (and social media) will keep you up. But reading that same delicious trash in book form will actually help you fall asleep. (I personally recommend Dungeon Crawler Carl as the perfect way to drift off. It also works as an audiobook!)


How do you fall asleep? Has anything made a big difference in your bedtime ritual? Have you tried that pigeon thing? (I hope not.) Hit reply or let me know in the comments!

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The Science of Better

This is a newsletter about the science of living better, by the author of The Power of Habit and Supercommunicators. It's a brief newsletter with advice, rooted in science, that helps us all get a little better at life.

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