If you have not already done so, please read Blog Posts 1 through 5 that describe how sleep is important and beneficial. I will post specific information for parents and children based on my book, “Healthy Sleep Habits, Happy Child.” Please do not be put off by my book’s length. This is a reference book. Read only the topic of interest to you.
A 2021 paper compared two matched groups of 8-month-old babies, one in the Netherlands and one in the U.S.A. “The Dutch infants averaged 13.7 hours of total sleep per 24 hours, 1.7 hours more than the U.S. infants; this difference was mostly due to daytime sleep.” Sleep in different cultures is also discussed in Blog Posts 14, 64, and 65.
Dutch parents were influenced by strong culturally shared beliefs that emphasized “the three R’s”: ‘rust’ (rest); ‘regelmaat’ (regularity), and ‘reinheid’ (cleanliness). Sleep is a major part of the notion of ‘rust’ (rest). The theme is Restful Regularity. Observations suggest that the Dutch mothers generally provide lower levels of stimulation to their children compared to US mothers. Most families lived within easy walking or biking distance of shops and school and had friends and relatives nearby. Non-maternal day care at home was most frequently provided by the father or other relatives. Sometimes the infants napped outside because the parents believed that fresh air-cool or even cold- was healthy for children.
American parents were influenced by strong culturally shared beliefs that emphasized ‘stimulation’ because they believe that stimulation boosts baby’s brain power and advances cognitive development. The theme is Developmental Stimulation. Most families had to drive for shopping or visiting friends or family. Sometimes the infants napped in the car during a trip, or the car ride was used to help the child take a nap. Non-maternal care day care was usually provided by a hired baby-sitter.
When a baby begins to fuss a little, American mothers might offer a toy, thinking that the child is bored. but the Dutch mother thinks, “Oh, are you tired?” and soothes the child for a nap.
|Nap in car||0%||8%|
|Non-maternal day care (Over 3 consecutive days)||1 hour||3 hours|
Objective sleep recordings showed group differences in Quiet Sleep and Active Sleep. In general, during Quiet sleep, there is regular breathing and very little body movement and the eyes are closed without rapid eye movements. Active sleep is more like REM sleep.
“Human growth hormone is secreted during Quiet Sleep and the substantial greater amount of Quiet Sleep among the Dutch infants may contribute to the current status of the Dutch as the tallest population in the world.” How more sleep makes your child taller and slimmer is discussed in Blog Post 23.
I asked the Co-director, Center for Sleep and Circadian Sciences at Stanford University whether the long naps in the Dutch infants might reduce homeostatic pressure for sleep at sleep onset at night and this reduced homeostatic pressure for sleep at sleep onset at night might cause an earlier onset of Quiet Sleep at night. His answer was yes, “based on models and studies intentionally manipulating the relationship between circadian and homeostatic mechanisms.”
What this means in plain English is that the timing and duration of naps might have a direct effect on the quality of night sleep (and vice versa). In particular, the Dutch infants did not have an earlier bedtime than the American infants, but the Dutch infants spent more time in Quiet Sleep than the American infants. And the first period period of Quiet sleep at night for the Dutch infants occurred earlier in the evening compared to the American infants.
Maybe longer naps has an effect on the quality of night sleep resulting in a taller child!