How much do babies sleep?
[mme_highlight] During the first year of life, babies’ sleep and wake patterns change, mostly influenced by the interaction between the baby’s development and environmental factors. Duration of sleep decreases with age, while the consistency of sleep improves with age. It is important to provide a soothing sleep setting and consistent sleeping habits since birth. [/mme_highlight]
During the first year of life, babies’ sleep and wake patterns change, mostly influenced by the interaction between the baby’s development and environmental factors. The sleep is often a subject of concern among parents, who question about what is a normal sleep, if their infant’s sleep requirements are being met or if there is some problem.
Infants: a unique pattern of sleep
The sleep pattern of a healthy infant is quite different from that of adults. The most distinguishing feature is that it is longer: 16 to 18 hours per day. In addition, the REM (rapid eye movement) phase occurs at sleep onset and its duration is increased in babies.
“Sleeping through the night” is a complex phenomenon, although it does not imply, as often believed, sleeping without awakening during all night. To sleep through the night, the baby must acquire the following skills:
- Capability to sustain period of sleep.
- Capacity of self-soothing in order to independently reinitiate sleep during the night.
- Consistent development of these skills ideally during the same nocturnal period during which the other family members sleep.
Recent studies have shown that the greatest change in the ability to sustain the sleep period is within the first three months of age, particularly between the first and second months. Hence, it is important to provide a soothing sleep setting and consistent sleeping habits since birth.
In fact, with the maturation of the central nervous system of infants some changes occur: decrease in the total sleep time and in the duration of REM sleep. Thus, in children, the phase at the onset of sleep is the NREM (non rapid eye movement) and not the REM, like in infants.
How does the sleep duration change throughout childhood?
As the table below shows, there is a consistent decline in the sleep duration as the child growths. Data from studies estimate that the decline in the sleep duration is about 10.5 minutes per month between the first and sixth months of age and 5.4 minutes per month between the seven and twelve months of age. Later the rate of declining slows: the duration of sleep approximately diminishes 7.8 minutes per year between one and four years and then from five to twelve years about 5.9 minutes per year.
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Mean period of sleep in children by age.
| Age | Mean period of sleep (24 hours) |
|---|---|
| 0-2 months | 14,6 h |
| 3 months | 13,6 hours |
| 6 months | 12,9 hours |
| 9 months | 12,6 hours |
| 12 months | 12,9 hours |
| 1-2 years | 12,6 |
| 2-3 years | 12,6 |
| 4-5 years | 11,5 hours |
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Night waking impairs sleep consolidation and shortens sleep. This table, based on data from various studies, evidences the decline in the number of waking per night with age. Thus, not only the sleep consolidation improves with growth, but mostly during the first months, as stated above.
[mme_databox]
Night waking in infants
| Age | Mean number of wakings per night |
|---|---|
| 0-2 months | 1.7 |
| 3-6 months | 0.8 |
| 7-11 months | 1.1 |
| 1-2 years | 0.7 |
[mme_databox]
What are the problems of inadequate or short sleeping?
- Negative impact on behavior and cognitive development.
- Poorer neuropsychological functioning in adolescence.
- Obesity: recent studies have come to the conclusion that children who do not get enough sleep are at increased risk of becoming overweight.
- Higher Blood Pressure: investigators found that blood pressure is elevated in children who sleep less.
Summary and Recommendations
- Implementing sleeping habits and providing a soothing sleeping setting should be priorities since birth.
- Duration of sleep decreases with age, while the consistency of sleep improves with age (less night waking per night in older children).
- Inadequate sleeping has a negative impact for babies and children, principally regarding behavior and cognitive development.
- Poor quality of sleep increases the odds for a child to be overweight or to have high blood pressure.
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References
- Galland BC; Taylor BJ; Elder DE; Herbison P. Nora sleep patterns in infants and children: a systematic review of observational studies. Sleep Medicine Reviews: vol 16, issue 3; p. 213-222.
- Henderson, JMT; France KJ; Blampied NM. The consolidation of infants’ nocturnal sleep across the first year of life.
- Anders TF, Sadeh A, Appareddy V. Normal sleep in neonates and children. In: Principles and Practice of Sleep Medicine in the Child, Ferber R, Kryger M (Eds), W.B. Saunders, Philadelphia 1995. p.7.
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