Healthy Sleep Habits, Happy Child Read online

Sleep Regularity

  The best time for your child to fall asleep at night is when she is just starting to become drowsy, before she becomes overtired. For young children in day care, dual-career families with long commutes, older children with scheduled activities, or teenagers with tremendous amounts of homework, it may be impossible to catch that magical drowsy state. These children will be better off if the bedtime is occurring at approximately the same time every night. For teenagers, this might mean consistent bedtimes throughout the week with later times on the weekends. In one study, regularity of the bedtime schedule was assessed in 3,119 high school students. They discovered that a more irregular sleep schedule was associated with more daytime sleepiness. These teenagers had lower grades, more injuries associated with alcohol or drugs, and more days missed from school. Going to bed around 11:00 P.M. compared to sometimes 10:00 P.M. or midnight might produce the same amount of sleep, but the more regular schedule is probably better.

  Another report examined the sleep of 202 children between four and five years of age. Here, too, variability in bedtime was associated with daytime problems described as “less optimal” behavioral adjustments in preschool. For example, these children did not “comply with teacher's urging to join an activity,” “show enthusiasm for learning something,” and they argued and fought more than other children. The authors thought these children with chronically variable sleep schedules might experience states similar to jet-lag syndrome characterized as nagging fatigue and cognitive disorientation. This particular study examined the role of family functioning as well as school behavior and concluded that the link between sleep behavior and school adjustment was not a common by-product of family stress.

  A bedtime that never varies, for example, always putting your preschool child to sleep at exactly 7:00 P.M., does not take into account the biologic variability, from day to day, of activity levels or lengths of naps. So it makes sense to vary the bedtime by thirty to sixty minutes based on how your child looks and behaves during the late afternoon. On the other hand, for older children who are not napping, having bedtimes that are hours earlier or later from day to day has been shown to be unhealthy.

  PRACTICAL POINT

  Even if the bedtime is too late, a regular bedtime is better than an irregular bedtime.

  Biological Rhythms

  To better understand the importance of maintaining sleep schedules, let's look at how four distinctive biological rhythms develop. First, immediately after birth, babies are wakeful, then fall asleep, awaken, and fall asleep a second time over a ten-hour period. These periods of wakefulness are predictable and not due to hunger, although what causes them is unknown. Thus a partial sleep/wake pattern or rhythm emerges immediately after birth. Second, body temperature rhythms appear and influence sleep/wake cycles. Body temperature typically rises during the day and drops to lower levels at night. At six weeks of age, temperature at bedtime is significantly higher than later in the night. After six weeks of age, as temperatures fall more with sleep, the sleep periods get longer. By twelve to sixteen weeks, all babies show consistent temperature rhythms. It is exactly at six weeks of age when evening fussiness or crying begins to decrease from peak levels and night sleep becomes organized, and it is at twelve to sixteen weeks when day sleep patterns become established.

  A third pattern is added by three to six months of age, when the hormone cortisol also shows a similar characteristic rhythm, with peak concentrations in the early morning and lowest levels around midnight. (This hormone is related to both mood and performance and will be discussed further in Chapter 3.) Interestingly, a part of the cortisol secretion rhythm is related to the sleep/wake rhythm and another part is coupled to the body temperature rhythm. I wish Mother Nature were simpler!

  Melatonin rhythmicity is a fourth pattern to consider. Initially, a newborn has high levels of circulating melatonin, which is secreted by the mother's pineal gland and crosses the placenta. Within about one week, the melatonin that came from the mother has disappeared. At about six weeks of age, melatonin begins to reappear as the baby's pineal gland matures. But the levels are extremely low until twelve to sixteen weeks of age. Then melatonin begins to surge at night, and the hormone appears to be associated with evolving sleep/wake rhythms by about six months of age. (Melatonin supplements should not be given to babies or young children to make them sleep better; there is no evidence that it is safe.)

  Even at only a few months of age, then, interrelated, internal rhythms are already well developed: sleep/wake pattern, body temperature, and cortisol and melatonin levels. In adults, it appears that a long night's sleep is most dependent on going to sleep at or just after the peak of the temperature cycle. Bedtimes occurring near the lower portion of the temperature cycle result in shorter sleep durations.

  Shift work or jet travel in adults, or parental mismanagement in children, might cause disorganized sleep. What is “disorganized sleep”? When you are awake but your body clock is in the sleep mode or when you crash from exhaustion when your body clock is in the awake mode, then your wakeful-ness or sleep is occurring out of phase with many biological rhythms. The result is poor-quality sleep or poor-quality wake-fulness. Imagine the sound from an orchestra if the violin section started to play their part after the woodwinds had already started!

  Many studies have been conducted with shift workers and in sleep labs on the internal desynchronization of circadian rhythms, the uncoupling of rhythms that are normally closely linked, and shifting rhythms that are out of phase with one another. The most common complaints in these adults are headaches and abdominal pain. Such people appear healthy and can function reasonably well except for the fact that they have pain in their head and/or stomach.

  REMINDER

  Never wake a sleeping baby.

  There is a large pediatric literature on headaches and recurrent abdominal pains; also, this is very familiar territory to parents of school-age children who have highly scheduled, busy lifestyles. Additional consequences of disorganized sleep include fatigue, stress, and perhaps chronically elevated cortisol levels. Once in place, a pattern of disorganized sleep sets in motion other specific sleep disturbances, such as night waking or an inability to fall asleep easily. Furthermore, recent research has shown that the hormones that are important to regulate sleep are also involved with the immune system, which helps us to fight infections. And research has shown that even modest sleep loss can impair cellular immune function. An article published in Science News in 2002, “Missed ZZZ's, More Disease: Skimping on sleep may be bad for your health” describes how “poor sleep habits are as important as poor nutrition and physical inactivity in the development of chronic illness.” They specifically cite obesity, diabetes, and cardiovascular disease. Although this article addressed adult health concerns, there is a growing concern that too many of our children are becoming more overweight or obese. So remember what our grandmothers used to say: “Early to bed, early to rise, makes you healthy …”

  I often tell parents to become sensitive to their child's personal sleep signals. This means that you should capture that magic moment when the child is tired, ready to sleep, and easily falls asleep. The magic moment is a slight quieting, a lull in being busy, a slight staring off, and a hint of calmness. If you catch this wave of tiredness and put the child to sleep then, there will be no crying. I like the analogy of surfing, because timing is so important there, too—you have to catch the wave after it rises enough to be recognized but before it crashes. But if you allow a child to crash into an overtired state, it will be harder for him to fall asleep, because he is trying to fall asleep out of phase with other biological rhythms. His ride to sleep then will not be easy or pleasant. Timing is most important! Remember, not every sleep wave is the same, and not every child learns quickly how to ride his sleep wave. But as with everything else, after practice it occurs effortlessly.

  Cumulative Sleepiness

  It's been known for many years that the effect of lost sleep accumul
ates over time. When you constantly have insufficient sleep, the sensation of sleepiness when you should be awake increases progressively. Let me explain what this means by giving an example. When adult volunteers have their sleep shortened by a constant amount, impairments in their mood and performance can be measured during the day. If the sleep disruption is repeated night after night, the actual measured impairments do not remain constant. Instead, there is an escalating accumulation of sleepiness that produces in adults continuing increases in headaches, gastrointestinal complaints, forgetfulness, reduced concentration, fatigue, emotional ups and downs, difficulty in staying awake during the daytime, irritability, and difficulty awakening. Not only do the adults describe themselves as more sleepy and mentally exhausted, they also feel more stressed. The stress may be a direct consequence of partial sleep deprivation or it may result from the challenge of coping with increasing amounts of daytime sleepiness. Think how hard it would be to concentrate or be motivated if you were struggling every day to stay awake.

  If children have constant amounts of sleep deficits, do they show these same escalating problems during the day? Yes! I believe the young child's brain is as sleep-sensitive as, if not more so than, an adult's. It is also possible that severe or chronic sleep deficits occurring early during the period of rapid brain growth might hard-wire circuits to produce permanent effects. This would be difficult to prove, because young children cannot report how they feel and we assume it is “natural” for them to have difficult temperaments, have tantrums, get frustrated, become easily angry, and so forth. In addition, in older children we have learned to accept as “normal” vague neurological differences—learning difficulties or attention deficit hyperactivity disorder (which, oddly enough, we treat with stimulant medications).

  The problem with concluding that constant sleep deficits are associated with these problems is that early nighttime sleep deficits may be mild and masked by long naps. If the brain has been permanently changed due to severe or chronic sleep loss, then, when the naps disappear and school requires more mental vigilance and focused attention, preexisting problems may appear. It is not simply academics that might suffer. We do not know the contribution of healthy childhood sleep toward creativity, empathy, a sense of humor, or adult mental health. Part of the problem is, of course, that we don't have yardsticks to measure items such as creativity or empathy, so we do not yet have a way to measure the contribution that healthy sleep during childhood might make.

  I do know that many parents keep their child up an extra twenty or thirty minutes at night to have fun, and notice no problems in the beginning. Later they call and ask why their “good sleeper” is now resisting bedtime or is cranky in the morning for “no obvious reason.” Because the change in routine was small and in the past, they don't even think about it. But during our conversation they will recall that because of the longer spring and summer days, or because “it didn't seem to cause any problems,” they pushed the child's bedtime back. The interval between allowing the too-late bedtime and the emergence of sleep-related problems was months in young children who had always in the past been well rested and were taking good naps, or weeks in children who were always on the edge of being overtired anyway. When such parents were asked if they thought their child appeared able to go to sleep twenty or thirty minutes earlier, the answer was almost always yes.

  MAJOR POINT

  Small but constant deficits in sleep over time tend to have escalating and perhaps long-term effects on brain function.

  In older children who have outgrown naps, the interval before the effects of cumulative sleepiness show themselves may be very long because of high motivation in the child and many exciting parent-directed events such as classes, lessons, or excursions, which help mask impaired vigilance or performance. The right bedtime is based on your child's age (see previous graphs for age-appropriate norms) and your child's behavior, mood, and performance, especially in the late afternoon.

  Twenty-five-Hour Cycles

  Although harmonious biological rhythms promote healthy sleep, random bad days are bound to occur. One explanation for “off” days, when the child's sleep is irregular for no apparent reason, is that our basic biological clocks have about twenty-five hours in their cycle, not twenty-four. In other words, without time cues, our free-running sleep/wake rhythms appear to complete one full cycle every twenty-five hours. As long as we train our children to match sleep/wake rhythms to night and day, problems are usually avoided. Other babies appear to get off schedule every few weeks and parents then must work to keep them well rested. I suspect that babies, like adults, differ in their individual ability to adjust their twenty-five-hour biological rhythms to society's twenty-four-hour clocks. Most parents, however, find that the effort to reset a baby's clock is worth it, because otherwise the child becomes increasingly tired and crabby.

  When parents make the effort to help the child get needed sleep, the child becomes better rested, and it becomes easier for her to accept sleep, to expect to sleep, to take long naps, and to go to sleep by herself. Some parents always have to endure days of disruption following trips, illnesses, or immunizations because any irregularity of schedule upsets sleep rhythms.

  Here is one family's account.

  SUSAN'S NIGHT WAKING

  Last summer, Susan's night waking had become so frequent that she was basically awake more than she was asleep. We had been instructed by a pediatrician at the parenting class we attend to “meet our child's needs.” So we were getting up as frequently as she asked and rocking her back to sleep. This happened three or four times a night and often took thirty to sixty minutes. A part of me wanted to do this. Needless to say, however, after months of this nighttime routine, my husband and I became quite exhausted and began to resent our child. I knew I was in trouble when I would get up and go into the baby's room and yell at her and then begin crying myself. The point I'm trying to make is simple: When a problem like a child's sleep habit gets out of hand, the parents are partially responsible.

  Finally, on our own, we decided to let her cry it out. By the way, my husband had a much easier time psychologically with letting her cry. He knew it was in her best interest and was able to remain unemotional about it. It took about a week, and she cried for about two hours for quite a few of those nights. Finally it seemed that she had gotten the idea.

  Unfortunately, the next week we were scheduled to go on our summer vacation. We didn't want to cancel the trip, but we knew we were taking a chance on destroying the results of our hard work. We stayed at an inn, and there were no cribs, so we made a sleeping area for Susan in the corner of the room. She'd wake up in the middle of the night and think it was playtime.

  When we got back from the trip we tried to get into the routine of letting her cry it out, but by that time we didn't have the energy to go through a week of crying again. So we fell back into a poor nighttime routine. Another month went by, and we knew we could not go on. We discussed it with the teacher at our parenting class, and she finally recommended the process of just letting Susan cry it out. This time it took about five days before she was back to sleeping through the night. The improvement lasted about a month.

  Susan received a vaccination shortly after that. I went into her room for only a moment to check on her one night. Then she began waking each night, and we were into our old routine. We repeated the process yet one more time. I think it took about five nights to get her to sleep through the night again. After that, Susan slept through the night regularly for months. She eventually asked to be put down before she was asleep at night rather than being rocked to sleep. She began taking long naps this spring, which seemed slightly strange.

  This summer when we went on vacation Susan slept in a crib in our room. She'd awaken in the night and again think it was playtime. It didn't take long for her to get back into her old bad habits. We had hoped we were beyond that, since she had been sleeping through the night for so many months … but since our trip she's been up at nig
ht practicing long dialogues, and it looks like we'll have to go through this one more time.

  This sounds like the story of a child who is always on the edge of being overtired and in whom natural disruptions are not easily tolerated. Slightly overtired children are more easily thrown off balance and take longer to recover. Well-rested children tend to be more adaptable and take occasional changes of routine in stride.

  PRACTICAL POINT

  A well-rested baby with a healthy sleep habit awakens with a cheerful, happy attitude. A tired baby awakens grumpy.

  Sleep Positions, SIDS

  A common myth held by Western parents is that all children sleep better on their stomachs. Yet a Chinese mother whose baby preferred to sleep on her stomach said she knew something was very wrong with her infant, because all Chinese babies sleep on their backs! She truly worried that stomach sleeping was unhealthy.

  The truth is that some babies seem to sleep better and fuss or cry less when asleep on their backs. Contrary to many parents’ fears, sleeping on the back does not cause a misshapen skull. In the past, tradition and social circumstances dictated which sleeping position most parents selected. Now it appears that sleeping on the back is healthier because it helps prevent sudden infant death syndrome. Fortunately, most babies sleep equally well on their backs as on their stomachs.

  A variant of the myth that babies sleep better on their stomachs is that when the child at five months rolls over, away from the sleeping position selected by the parents, the parent has to intervene and roll the child back. Actually, leaving the child alone allows the child to learn to sleep in different positions. If you roll your child back and he instantaneously returns to sleep, obviously there is no problem. On the other hand, going to your child to roll him back can become a game for the infant by five months of age. Games should occur at playtime, not when it's time to sleep. Remember, not going to your baby allows him to learn to roll back alone, learn to sleep in the new position, and learn to remember the next night not to roll in the first place.