Although many people associate night wakings with infants, all healthy people—whether they realize it or not—experience multiple arousals during the night.
When children are aroused in the middle of the night, they may fall back asleep quietly on their own. It’s only when kids don’t fall back to sleep quietly—but wake up their parents instead—that night arousals are perceived to be a problem.
And it’s a common problem.
A Swiss study that tracked kids from birth reports that over 30% of kids between 2 and 7 experienced at least once disruptive night awakening each week. Among 10 year olds, the rate remained high--almost 23% (Jenni et al 2005).
In this article, I review the science of interrupted sleep:
• Why nobody really “sleeps through the night”
• Why baby sleep is more fragmented than adult sleep
• Causes of frequent or disruptive awakenings in kids
• What to do if your child awakens frequently at night
Night wakings: Why nobody really “sleeps through the night”
Perhaps you’ve heard parents brag that their children are “sleeping through the night.” This isn’t happening in your family, and you’re wondering what’s wrong.
Your baby seems to be a light sleeper. She’s easily aroused at night and (when things get really difficult) she seems capable of waking up every hour.
Or--if you have an older child--you wonder why he is still having trouble sleeping through the night at an age when other kids are sleeping like logs.
Why is your kid troubled by night wakings?
Possibly, your child suffers from a medical condition, like gastroesophageal reflux disease or sleep apnea.
But there is another, more general answer to this question—an answer that applies in cases where there is nothing medically or psychologically wrong.
“Sleeping through the night” is a myth.
Nobody sleeps through the night. Babies, children, and adults all experience arousals as they sleep.
When an adult falls asleep, she doesn’t pass out for 7-9 hours at a stretch. Instead, her sleep patterns are defined by short sleep cycles that last about 90-100 minutes.
Each sleep cycle is a sequence of sleep stages, beginning with relatively brief, light stages of sleep, progressing through stages of deep sleep, and ending with REM (rapid-eye movement) sleep, the sleep state associated with dreams.
At the end of a sleep cycle, the sleeper may begin the cycle all over again.
But she might also awaken.
People are easily aroused during, and immediately after, REM sleep. And sleep studies that record brain activity show that people experience multiple arousals during the night -- about 10-20 per hour (Bonnet and Arand 2007). If we aren’t aware of these arousals, it’s because we sink back into sleep very quickly and don’t remember the disruption in the morning.
But of course many people are aware of waking up in the middle of the night.
They may have trouble getting back to sleep for an hour or more. If they live in a modern industrialized society--or any other setting that discourages daytime napping and requires people to report to work at the same time every day--they may complain to their doctor that there is something wrong. And they may be diagnosed with a medical or psychiatric disorder--“secondary insomnia” (Dement and Vaughan 1999).
But are night wakings really a pathology? The cross-cultural evidence suggests otherwise.
Ethnographic and historical research indicates that “sleeping through the night” is a recently-invented Western ideal (Worthman and Melby 2002; Ekirch 2005).
In most historical times and places, humans haven’t expected to get all their sleep in one, nightly stretch of 7-9 hours.
Instead, they met their sleep needs in at least two distinct sleep sessions (sometimes called “first sleep” and “second sleep”). They may have also taken naps during the day.
This was the pattern in Europe before the Industrial Revolution (Ekirch 2005). And it’s still the pattern in many non-Western cultures today.
For instance, modern-day hunter-gatherers--like the !Kung san and Efe--have no fixed bedtimes, and people tend to nap opportunistically (Worthman and Melby 2002).
Moreover, Westerners tend to adopt the two-phase sleep pattern when they are denied access to artificial lighting.
In an experiment conducted by the National Institute of Mental Health, eight men who normally slept about 7 hours a night were confined to darkness for 14 hours a day (mimicking natural lighting conditions in high latitudes during the winter).
At the beginning of the study, these men began sleeping about 11 hours--as if they were catching up on their sleep. But afterwards, they settled into a new pattern, sleeping in two separate intervals, each lasting 4-5 hours long (Barbato et al 1994).
The bottom line?
Night wakings are not a pathology or abnormality. On the contrary, they are almost certainly the normal pattern for our species.
This doesn’t mean that night wakings don’t present a problem to sleepless parents. But it does suggest that some Westerners have unrealistic expectations about sleep.
The better we understand the biology and anthropology of sleep, the better we can cope with night wakings in babies and children.
Why do babies experience frequent night wakings?
Babies have shorter sleep cycles, and they spend proportionally more time in “active sleep,” the baby equivalent of REM. They also have smaller stomachs, which means they need to eat more frequently than adults do. Put these traits together, and you get a creature that sleeps lightly and needs to awaken every few hours.
This is especially true for newborns, who may awaken for feedings every two hours. But older babies are also likely to experience night wakings. In one study that recorded the sleep patterns of healthy 2- and 9-month old infants, babies averaged 3 major awakenings each night (Anders 1978).
Why, then, do some parents claim their babies sleep
through the night? Most likely, they are simply unaware of their
infants' brief night wakings. The issue, then, isn't whether or not your
baby wakes up during the night. It's whether he also wakes you up.
For tips on coping with baby night wakings, see this article on baby sleep patterns.
And what about big kids?
Many people expect children to sleep soundly throughout the
night. But as we've seen, interrupted sleep is normal for adults and
infants. It's also normal for big kids.
In fact, if you think your child doesn't wake up, you are mistaken. That's the implication of studies that monitor children's sleep with actigraphs. When researchers compared objective data with subjective, parental reports, they found that parents consistently underestimated how frequently their kids awakened during the night (e.g., Holley et al 2010; Kushnir and Sadeh 2013).
waking up doesn't mean your child is unhealthy, immature for his age,
or maladjusted. But some night wakings are symptomatic of real problems,
and these problems should be addressed.
Here are some common causes of night wakings—and advice for coping with them.
• Nighttime fears and separation anxiety. Worried, frightened kids have more sleep problems, including disruptive night wakings (Petit et al 2006; Gregory et al 2005; Kushnir and Sadeh 2011; Meltzer et al 2013). There is no evidence that nighttime fears or separation anxiety will diminish as a result of sleep training. In fact, research suggests that ignoring your child’s fears may lead to nightmares and emotional problems. So it’s important to take an active role in teaching your child to overcome her fears. For more information, see this article on nighttime fears in children.
• Nightmares. Nightmares are frightening dreams associated with REM sleep, and they are more likely to occur after a child has been sleeping for several hours. When a child wakes up immediately after a nightmare, she is likely to remember it. Triggers for nightmares include stress, anxiety, traumatic events, and medications that interfere with REM sleep (Moore et al 2007). Kids who awaken from nightmares need to be reassured that their dreams weren’t real. To help kids cope with emotions associated with nightmares, see my article on nighttime fears in children.
• Night terrors. Like nightmares, night terrors are distressing, disruptive, and cause night wakings. But night terrors differ from nightmares in several key respects. A child may move--even sleep walk--during a night terror, which puts him at risk of hurting himself. For help distinguishing night terrors from nightmares--and for tips on treatment--see this article on night terrors in children.
• Overtiredness. When people are overtired, their sleep may become more restless and they suffer more frequent night wakings. If your child is overtired, he needs more sleep. For tips on getting him to get to sleep earlier at night, see this article on bedtime problems in children.
• Snoring and other forms of sleep-disordered breathing. Sleep disordered breathing (SDB) includes snoring, loud breathing, troubled breathing and interrupted breathing (apnea) during sleep. SDB can restrict the oxygen supply to a child’s brain and cause serious health problems. It is also associated with poor sleep quality, nighttime crying, daytime sleepiness, attention problems, hyperactivity, and frequent night wakings (e.g., Fukumizu et al 2005; Hiscock et al 2007; Shur-Fen Gau 2006). If you suspect your child suffers from sleep-disordered breathing, consult your physician.
• Full or irritable bladders. Kids may be awakened during the night be the urge to urinate, so it’s wise to avoid drinking fluids before bedtime. But some children may have urinary tract problems that awaken them even when their bladders aren’t full. Girls are especially prone to urinary tract infections because the female urethra is very short—making it easier for germs to enter the body. If your child has frequent night wakings, try to find out if bathroom trips are contributing to the problem.
• GER (gastroesophageal reflux). Kids who suffer from gastroesophageal reflux (stomach acid in the esophagus, also known as heartburn) may experience frequent night wakings. GER is associated with sleep-disordered breathing and can be—in some cases—dangerous. If you think your child may suffer from GER, consult your physician for treatment options. Meanwhile, avoid acidic and hard-to-digest foods before bedtime.
• Headaches. A recent Polish study of 284 kindergarten and school-aged children reports that kids who suffered from headaches were more likely to suffer from frequent night wakings (Zarowski et al 2007). Similar results have been reported for kids in the United States (Long et al 2010) and Italy (Carotenuto et al 2005). It’s not clear if the headaches are causing the sleep problems, or the sleep problems are causing the headaches. Either way, it’s a good idea to have your child’s headaches investigated by a physician.
• Stress. Like adults, kids experience sleep problems when they are under stress. Children who’ve experienced traumatic events are likely to suffer from nightmares and other sleep disturbances (Sadeh 1996). But everyday stressors disturb sleep, too. For instance, kids experiencing family stress suffer more night wakings and get less sleep overall (El Shaik et al 2006; Sadeh et al 1999). And these sleep problems are associated with elevated stress hormone levels (El Shaik et al 2008).
• Sleep-onset associations. According to a prevailing theory among Western sleep researchers, kids often learn to associate falling asleep with certain forms of stimulation—like parental soothing or a particular sleep environment. These sleep aids may be very effective, but if kids become dependent on them, they fail to learn how to fall asleep on their own. So if your child is used to falling asleep in your presence, but wakes up alone, he may not be able to settle himself back to sleep (Moore et al 2006). If you want your child to develop self-soothing skills, you may want to consider sleep training. For more information, see these articles on "no cry" sleep training and the Ferber method.
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