There are five main elements of healthy sleep for children:
- Sleep duration: night and day (Blog Post 6).
- Sleep consolidation (Blog Post 11).
- Sleep schedule, timing of sleep, bedtime (Blog Post 8).
- Sleep regularity (Blog Post 12).
Why Naps are Beneficial
- Naps Reduce Stress: Levels of cortisol dramatically fall during a nap, indicating a reduction of stress in the body. Not taking a needed nap means that the body remains stressed.
- Naps Enhance Emotional- and Self-Regulation: In toddlers of 30–36 months, Dr. Rebecca Berger experimentally eliminated a single nap. She noted that when only one nap is eliminated, “acute sleep restriction causes dampened positive emotion displays when positive responses are expected (solvable puzzle), as well as increased negative emotion under challenging conditions (unsolvable puzzle).” Experimental acute nap deprivation revealed that “toddlers [were] neither able to take full advantage of positive experiences nor as adaptive in challenging contexts. If insufficient sleep consistently ‘taxes’ young children’s emotion responses, they may not manage emotion regulation challenges effectively, potentially placing them at risk for future emotional/behavioral problems. Specifically, when children were given the opportunity to complete an age-appropriate puzzle, they showed less joy and pride when sleep restricted than when optimally rested. When children were faced with a puzzle with no solution, they showed significantly more worry/anxiety when sleep restricted than when well rested. In sum, Dr. Berger continued, “sleepy children may view and respond to the world differently than children who are well-rested: they may not be able to take full advantage of positive experiences and may not be as able to manage challenges. A lack of sleep in contexts that rely on young children’s mastery of new information (e.g., preschool) may have significant and potentially dire long-term consequences [Emphasis added].” See Blog Posts 15 and 50.
A study of children 3–5 years old examined the effect of experimental nap deprivation and showed that naps influence emotional processing. “Without a mid-day nap, attention to emotional stimuli is heightened and may impair the child’s ability to regulate emotions.” A video abstract of the article can be viewed at www.youtube.com/watch?v=JIoZ8mzxQgg.
Upset and frustrated when challenged. More emotional. Sound familiar? Now I think we know why children who miss their naps are more likely to have meltdowns or frequent witching hour problems. You can ask yourself, what is the magical power of a nap that turns a raving, manic, out-of-control 2.5-year-old into a sweet Prince Charming?
- Naps Modulate Temperament: My study of naps showed that at 4 months of age, longer naps are associated with the temperament characteristics of a more positive mood and longer persistence (Blog Post 48).
At 3 years of age, longer naps are associated with the temperament characteristic of more adaptability. Comparing 3-year-old children who napped with those who did not nap, adaptability, and only adaptability, was the temperament characteristic associated with those who napped. Adaptability rating was the temperament characteristic that had the highest correlation with total sleep duration. Also, adaptability was the only temperament characteristic correlated with the number of night wakings: more adaptable children had fewer night wakings. Finally, more adaptable children scored lower on a rating scale to measure ADHD behaviors.
Other research has shown that adaptability is the temperament characteristic most important for school success.
- REM Sleep Occurs During Naps: Not only are naps different from night sleep, but not every nap is created equal. There is more rapid eye movement (REM) sleep in the midmorning nap compared with the midday nap, in adults. During a nap, the duration of REM sleep within a nap, not simply the total duration of the nap, is related to creative problem solving. Research also suggests that high amounts of REM sleep, under the influence of low melatonin levels, help direct the course of brain maturation in early life. Further, adult studies have suggested that REM sleep is especially important for restoring us emotionally or psychologically, while deep, non-REM sleep appears to be more important for physical restoration. See Blog Post 15.
- Naps Consolidate Memories: Recent studies have shown that sleep following exposure to new knowledge is beneficial for memory consolidation in early infancy. Dr. Horváth showed that 3-month-old infants remembered a cartoon face about one and a half to two hours after its first presentation only when a nap followed the learning. That is, the nap consolidated the memory. “Infants who did not nap after the learning showed no evidence of remembering the stimulus previously shown, whereas those infants who napped did remember. We propose that frequent naps during infancy are necessary for the efficient consolidation of information.” Another study by Dr. Horváth showed that children between 7 months and 3 years old who had more naps (but not longer total daytime sleep durations) had higher levels of vocabulary growth, suggesting that memory consolidation with frequent naps is better than with fewer but longer naps. In a similar study, by Dr. Konrad, among 15- and 24-month-old infants, those who were able to nap after a demonstration session were less likely to perform an irrelevant action for achieving a desirable outcome. This suggests that the nap selectively helps to discard aspects of a learning experience as being not useful or relevant (“pruning” Blog Post 50). In two other studies of 12-month-olds, Dr. Conrad confirmed the ability of a nap, following a demonstration, to improve performance, presumably due to memory consolidation. She wrote, “There was a significant positive relation between the number of naps during the retention interval and the imitation scores, suggesting that infants rely on frequent napping for memory consolidation.”
So please respect your infant’s need to nap, based on drowsy signs, even if naps occur frequently throughout the day. In addition to frequent naps enhancing memory consolidation, an experimental study on 15-month-old infants showed that naps less than thirty minutes do not promote memory consolidation. Please don’t worry if your baby has some very brief naps, but by watching for drowsy signs during the day and in the evening, when you synchronize your soothing-to-sleep to the time when your baby is starting to become sleepy, most naps will be more than thirty minutes.
(To be continued.)