Is there such a thing as “baby sleep deprivation”? How do we know if a baby is getting enough sleep? Here are the signs of sleep insufficiency, and the reasons we should care. When parents struggle with cranky, tired infants, it’s natural to wonder about chronic sleep loss. What does the research tell us? It’s clear that babies can cause sleep deprivation in others. But whether or not babies themselves suffer from sleeplessness is less clear. In my search for published studies about infants with insomnia, I’ve come up with almost nothing. Researchers acknowledge all sorts of infant sleep problems, including difficulty settling, too-frequent night wakings, sleep-disordered breathing, and medical conditions that can interfere with sleep, like GERD. Researchers also recognize the existence of something called “behavioral insomnia” in young children. But — to date — I haven’t found any scientific descriptions of chronic sleep restriction in babies. Maybe that’s a good thing — a sign that sleeplessness in babies is very rare. Babies may be able to regulate their own sleep needs very well, even amid the hustle and bustle of daily life. Still, you may have questions. How much sleep does your baby need? How can you tell if your baby isn’t getting enough sleep? Does chronic sleep loss during infancy have any long-term effects? What can we do to help babies sleep better? Here I review what the available evidence tells us. How much sleep does a baby really need? As I note elsewhere, the American Academy of Sleep Medicine (AASM) offers guidelines for infant sleep, but they are very broad. For example, they recommend that babies between the ages of 4 and 12 months sleep for a total of 12-16 hours over a 24-hour period. For babies between 12 and 24 months, the recommended range is 11-14 hours. Does this mean that your baby is getting enough sleep as long as your baby’s daily total falls into the specified range? No. Babies are individuals, with different personal needs. For example, an infant might sleep more than the recommended minimum, and nevertheless fail to get sufficient sleep for his or her optimal functioning. It’s also possible that some babies — like some adults — can flourish on somewhat less sleep. Around the world, many babies aren’t meeting the AASM’s recommendations (e.g., Paavonen et al 2020; Tham et al 2021), and we can’t assume that all of them are harmed as a result. In Singapore, babies who slept just 11.5 hours throughout the first 12 months experienced cognitive outcomes similar to babies who slept 12 hours or more (Cai et al 2023; Tham et al 2023). So there isn’t any single, magical number that represents the right amount of sleep for every child. My Parenting Science article about the normal range of sleep times in infants can help you figure out if your baby sleeps for an unusually short (or long) duration. But if you’re trying to understand your child’s personal sleep requirements, it’s important to pay attention to your child’s overall well-being. So how can you tell if a baby isn’t getting enough sleep? Pediatricians and experienced parents have noted these signs of “over-tiredness” in the very young: A noted lack of interest in people and the environment A tendency to look away from stimulating things Hand-to-face gestures: Pulling ears, rubbing eyes Fluttering eyelids Yawning For older babies and toddlers, signs may also include: Becoming more accident-prone Becoming more “clingy” Becoming ever-more active as the night wears on I’ve also culled several markers of sleep deprivation from the scientific literature: Poor recovery from negative emotions Feeding troubles Being hard to awaken Having a lower threshold for pain Let’s take these up in detail. Baby sleep deprivation is associated with poor recovery from negative emotions I’m sure you’ve experienced it yourself: Running short on sleep makes it harder to bounce back from negative emotions. We become moodier and more impulsive when we’re sleep-deprived. We have more trouble interpreting the emotions of others, and we’re more likely to perceive neutral stimuli as threatening (Ben Simon et al 2020). These difficulties have been documented in preschoolers as well as adults (Lassonde et al 2016; Berger et al 2012). But what about babies? They, too seem to be affected. In an experimental study, researchers deliberately disrupted the sleep of 14-month-old babies during a single laboratory “sleepover.” The following day, these babies showed poorer “emotional regulation,” i.e., they had difficulty recovering from negative emotions (Montgomery-Downs and Gozal 2006). Infant sleep problems are linked with feeding difficulties Researchers studying over 600 American babies, aged 6-36 months, found that babies with feeding difficulties (e.g., refusing to eat) fell asleep later at night and slept for shorter intervals. They were also more likely be diagnosed with “behavioral insomnia” (Tauman et al 2011). Does a lack of sleep cause feeding problems? Do feeding problems cause sleep loss? Or do these troubles go together for some other reason? We can’t know the answer from this study. It reports correlations only. But in a follow-up study, researchers found that both types of trouble tend to make parents feel more distressed (Golik et al 2013), and parental distress can fuel sleep problems. Sleep-deprived babies have more difficulty awakening Researchers have long noted the tendency in adults: When sleep-restricted or sleep-deprived people are finally given the opportunity to snooze, they spend proportionally more of their sleep-time in deep, “slow-wave” sleep (Elmenhorst et al 2008) — a state that is characterized by fewer arousals and greater difficultly awakening. Does the same pattern occur in babies? There’s some reason to think so. For instance, in an experiment on 8-week-old infants, researchers subjected babies to brief episodes of sleep deprivation, and then attempted to awaken them with blasts of white noise. Compared to their responses during a (non-sleep-deprived) control condition, the babies required louder noises before awakening (Franco et al 2004). And an earlier study of three-month-old infants yielded similar results (Thomas et al 1996). This might sound nice if you like the idea of a peaceful nap. But, as I explain elsewhere, it’s better if babies are more easily aroused from sleep because this means they will be less likely to sleep through a medical emergency. With this in mind, it’s concerning that babies subjected to short-term sleep deprivation may experience more sleep-disordered breathing, including obstructive sleep apnea (Canet et al 1985). Obstructive sleep apnea has been linked with a variety of health problems (Jennum et al 2013), and an increased risk of SIDS. Sleep restriction may make babies more sensitive to pain Controlled experiments confirm that chronic sleep restriction can lower our thresholds for pain. For example, an experiment on young adults found that people became more sensitive to painful stimuli after spending three weeks on a sleep-restricted schedule. These study volunteers — who were permitted to sleep only 4 hours on weekdays — also reported more frequent, spontaneous aches and pains, including headaches, back pain, and muscle aches (Simpson et al 2019). Do sleep-deprived babies experience similar effects? I don’t believe anybody has ever tested this on human infants (and perhaps they never will, given the obvious ethical considerations). However, an experiment on infant mice is concerning. When the mice were newborns, researchers restricted their total sleep by two hours each day. The treatment lasted for 10 days, after which the mice were free to sleep normally. Later — when the mice where adolescents — researchers tested their responses to pain by placing them on a hot plate. Compared to peers in a control group, the mice who’d experienced infant sleep restriction exhibited a lower tolerance for pain. Their threshold for heat pain was almost 25% lower (Araujo et al 2018). What does this mean? Mice aren’t humans, and it’s good to know that the increased sensitivity to pain wore off by the time the mice were adults. But, in combination with the research on human adults, this study lends weight to the idea that infant sleep loss might make babies more vulnerable to pain.