Pourquoi certaines personnes sont-elles si douées pour s'endormir?novembre 27, 2019
And if you’re not one of those people, what you can learn from them
The metaphor of “falling” asleep is a good one; it suggests a change from one state to another that is largely out of one’s control. While some people’s nightly tumble into sleep is quick and effortless, for others it can be frustratingly drawn-out.
Sleep experts refer to the transition from wakefulness to sleep as “sleep onset latency,” or SOL. And one of the most consistent findings from the SOL research is that people with sleeping issues like insomnia tend to overestimate the amount of time they require to drift off. A 1990 study from the American Psychological Association found that insomniacs believed that they took an average of 40 minutes to fall asleep, while EEG readings suggested that they actually fell asleep in 26 minutes. While exact time estimates have varied from one study to the next, this finding has been repeated over and over again in sleep experiments.
But the more scientists study sleep onset, the more they find evidence that it’s a dynamic and complicated process. A 2014 study in PLOS One found that as certain wake-associated patterns of brain activity switch off, other sleep-associated patterns switch on. But for some people who struggle to fall asleep at night, these events don’t coincide. It’s possible that while some people appear to be sleeping based on traditional EEG measurements, parts of their brain may still be active and preventing them from falling into a deep and restful slumber.
While science’s understanding of sleep onset is evolving, it’s clear that some people nod off easily while others struggle. Experts say the difference often comes down to helpful bedtime habits and proper conditioning — rather than some innate ability.
“You’ve got to tap the brakes and give yourself time to slow down before you turn in for the night.”
“People have looked at the genetics of being a good sleeper, but it’s spotty,” says Michael Grandner, an associate professor and director of the Sleep and Health Research Program at the University of Arizona College of Medicine. Likewise, the evidence linking cognitive traits to insomnia are mixed.
There is some solid research tying anxiety to insomnia. Women are nearly twice as likely as men to be diagnosed with an anxiety disorder, according to a 2016 review in the journal Brain and Behavior. And women are also more likely than men to experience insomnia. But while an anxious mind may be especially susceptible to restless nights overall, Grandner says poor bedtime routines and “teaching yourself to be a bad sleeper” are the most common causes of prolonged sleep onset or having trouble falling asleep in the first place. “If you want to make a turn in a car, you have to slow down first,” he says. The same is true when trying to drive your brain toward sleep. “You’ve got to tap the brakes and give yourself time to slow down before you turn in for the night.”
What does it mean to “tap the brakes?” Avoiding emotional interactions with friends and family members seems to be important. “Emotional activation is bad [for sleep], whether it’s arguing with a partner or using social media,” Grandner says.
Recent research suggests that social media may be inherently stimulating, and therefore an impediment to falling asleep. A 2018 study in the Journal of Adolescence found nighttime social media use boosted “pre-sleep cognitive arousal” and prolonged sleep onset. This is of a piece with other recent studies that have found social media may be a potent sleep repellent. Research is mixed on the effects of pre-bed TV or the consumption of other “passive” forms of media — meaning ones that don’t require interaction. But if the stuff you’re engaged with before bed makes you feel anxious, alarmed, or otherwise emotionally charged up, it’s likely going to forestall sleep.
“When you get into bed, if that’s the first time all day that your brain has had time to process things, it’s going to take that time and use it.”
When it comes to habits that promote swift sleep onset, Grandner says reading seems to be an ideal activity. “It’s a cliché, but reading doesn’t involve a lot of visual stimulation, it’s not social, and it doesn’t require much light,” he says. If you’re trying to decide how to spend your time in bed before turning out the light, grabbing a book seems to be a great choice.
It may also be important to take time earlier in the evening to let your brain wander and contemplate the events of your day. Research suggests that a brain incessantly bombarded with new forms of stimulation or information can feel uneasy and anxious. And Grandner says denying your brain breaks from stimulation can lead to racing and ruminative thoughts in bed. “For most of human history, people had a lot of free time when their brains weren’t engaged or distracted,” he says. That’s changed. “When you get into bed, if that’s the first time all day that your brain has had time to process things, it’s going to take that time and use it,” he says. “And unless you’re really exhausted, sleepiness won’t overpower that.”
It’s not necessary to spend an hour sitting quietly and meditating, he says. But going for a walk, doing the dishes, or folding laundry — without simultaneously listening to a TV or firing up a podcast — are the types of activities that facilitate productive mind-wandering, and so can help your brain clear out whatever accumulated thoughts it’s been storing up throughout the day.
There are plenty of other habits that can help or hurt sleep onset. Going to bed and rising at the same time each day can help set your body’s circadian clocks, which is important for healthy sleep. But of those variables you can control, taking time to properly wind down before bed can go a long way toward lowering your brain into the abyss of sleep — ensuring your fall into slumber will be a short one.