Adequate sleep is crucial for development and promotes brain maturation. Numerous studies have shown that chronic sleep problems in early life are associated with later cognitive, psychosocial, and physical health problems. However, until now, it was unclear to what extent everyday sleep behaviors (such as sleep duration, bedtimes) in infancy can be linked to brain activity during sleep - both acutely and in the long term. In our new study by Sarah Schoch et al. (1), the sleep behaviors of 32 healthy 6-month-old infants were measured using motion sensors and for the first time, compared with brain activity using high-resolution electroencephalography (hdEEG) to investigate the relationship between sleep in the brain and sleep behavior.
The study reveals four important relationships
- Daytime sleep (frequency and duration of naps) is associated with slow waves in the EEG (Slow Wave Activity, SWA).
- Nocturnal movements and awakenings are linked to the frequency of sleep spindles.
- The average bedtime is linked to brain connectivity.
- Brain connectivity at 6 months of age predicts nocturnal sleep duration at 12 months of age.
These novel findings expand our understanding that infant sleep behavior is closely linked to three aspects of brain activity: sleep pressure (determined by slow waves), thalamocortical system maturation (spindles), and cortical connectivity maturation (coherence).
The crucial next step is to extend this concept to clinical groups to objectively characterize sleep behaviors of infants who are at a higher risk of developing neurological or behavioral problems later on.
These findings can help develop a better understanding of how sleep behavior can impact development. For example, knowing how much sleep a child typically needs can help choose an appropriate bedtime and develop a regular sleep schedule.
So, how much sleep is adequate?
An 18-member expert panel has compiled scientifically based and current guidelines on sleep need (2). The appropriate sleep duration for healthy children with normal sleep behavior is:
- 14 - 17 hours for newborns
- 12 - 15 hours for infants
- 11 - 14 hours for toddlers
- 10 - 13 hours for preschoolers
- 9 - 11 hours for school-aged children
(1) Schoch et al, 2023, at Journal of Sleep Research https://doi.org/10.1111/jsr.13936
(2) Hirshkowitz et al, 2015, Sleep Health http://dx.doi.org/10.1016/j.sleh.2014.12.010
Translation: Luisa Burri
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