Healthy Sleep Habits, Happy Child
Forbidden Zone and Individual Variation
August 29, 2022

Found in age groups

Healthy Sleep Habits, Happy Child

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Healthy Sleep Habits, Happy Child

5th Edition: 
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A Healthy Child Needs a Healthy Brain, A Healthy Brain Needs Healthy Sleep

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.

Blog 94Forbidden Zone and Individual Variation

Among some adults, there appears to be a circadian period of high arousal between about 8-10pm. This has been called the ‘forbidden zone’ because it is difficult for well-rested adults to easily fall asleep during those hours. Also, lab investigations suggest that some infants may have a forbidden zone between 5-8pm. Is this observation of a forbidden zone, in some infants, incompatible with my general suggestion to strive for early bedtimes based on drowsy signs?


Some babies, during the first few months, especially around 6 weeks of age, and especially in the evening, quietly whine or whimper or fuss for no apparent reason. Others have mild to moderate crying bouts. A minority of infants (about 20%), during the first 2-4 months, have intense, prolonged, or inconsolable crying spells in the evening. Also, babies often have difficulty easily falling or staying asleep through the night. Among all infants, there is individual variation in a graded fashion in the amount of fussing and crying and the amount of sleeping. The association of increased crying and decreased sleeping in some infants may, or may not, be related to individual variation in the degree of arousal in the evening hours (the ‘forbidden zone’). So, trying for an early bedtime is worthwhile, but it might be easier to obtain in some infants than others.

My Blog emphasizes general principles, for example, early bedtimes are healthier than late bedtimes. Also, a goal of my book, Healthy Sleep Habits, Happy Child, is to focus on the fundamentals of children’s sleep. However, because of individual variation at any specific age range (Blog Post 14) and variations due to age differences, it is possible to discover what incorrectly appears to be inconsistencies in my advice (see above). Obviously, all general principles and all fundamental concepts do not always apply equally to all children at all ages. 

My advice is to focus on what is most helpful for your family and do what works best for your child. Even if you might be confused about some apparent discrepancy in my Blog or book, don’t let that interfere with paying most attention to the sleep basics that work for you, your family, and your child.

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Blog 14
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Be Flexible

Parents would like to have a plan that guarantees healthy sleep for their child, like a tested recipe guarantees a sweet cupcake. Unfortunately, there is not one plan that fits all families. The principles discussed in Blog Posts 1 through 13 have to be adapted to specific individual, cultural, and family circumstances, or what the Army calls “mission constraints.”
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