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.
As naps disappear, less day sleep occurs, and then, this might cause your child to begin to acquire a sleep debt that messes up night sleep. The previously customary bedtime was only slightly too late, but now with less day sleep, the previously slightly too late bedtime is way too late because there is less day sleep to partially compensate for a slightly too late bedtime. Your child now develops a higher state of neurological arousal because of less daytime sleep and starts to have difficulty falling asleep and staying asleep at night and early in the morning.
In all 5 situations, ‘Cumulative Sleepiness’ (Blog Posts 84–86) means that the adverse effects from a bedtime that is too late will worsen over time. Thus, a bedtime that is only slightly too late might initially seem to be not creating any problems, but later, “all of a sudden” your child hits a wall from an ever-increasing sleep debt. Now, bedtime battles, and/or night wakings, and/or nap deterioration, and/or extremely early wake-up times occur. If the bedtime is only slightly too late, it might take a long time before these sleep problems appear. Before these sleep problems become full-blown, your child’s mood, behavior, or sociability might have mildly or moderately worsened in the late afternoon or early evening and you might mistakenly attribute these behavioral/emotional symptoms and mild sleep issues to myths such as ‘teething’, ‘growth spurts’, or ‘sleep regressions’ (Blog Posts 36–37).