Catching Z’s - The Evolution of Sleep Science

Catching Z’s – The Evolution of Sleep Science


We have sort of this innate knowledge that sleep is important.  As nurses, and certainly, for any night shift nurses out there, we know what it’s like to function when we don’t get enough sleep and how much better we feel after a good sleep. But have you ever really considered why we sleep? 

Sleep Theories

One of the earliest theories of sleep, sometimes called the Adaptive or Evolutionary Theory, suggested that inactivity at night is an adaptation that served a survival function by keeping organisms out of harm’s way at times when they would be particularly vulnerable. 

Another theory, the Energy Conservation Theory, suggested that the primary function of sleep is to reduce an individual’s energy demand and expenditure during part of the day or night, especially at times when it is least efficient to search for food. 

Restorative Theories hold that sleep provides an opportunity for the body to repair and rejuvenate itself. 

Finally, the Brain Plasticity Theory, is based on evidence that sleep is correlated to changes in the structure and organization of the brain (Division of Sleep Medicine https://sleep.med.harvard.edu/).

Sleep Disorders for Infants

It may sound crazy to the average person, but it probably comes as no surprise to NICU nurses that there is such a thing as a sleep disorder for infants. Studies show that infants without mature sleep-wake cycling by 34 weeks gestational age have lower scores on neurodevelopmental indices, performed poorly on an infant’s mental development index, using the Bayley II developmental screening tool, than infants who spent more time in REM sleep during active sleep. Poor neonatal sleep also predicted longer gaze duration during a new visual recognition memory task and increased distractibility at 18 months (Graven & Browne, 2008).  

So what can NICU nurses do to help protect our patient’s sleep? 


Here are some examples from Leslie Altimier & Raylene Phillip’s Integrative Model of Developmental Care.

Never waken a sleeping baby unless necessary

  • Coordinate care with baby’s sleep/wake cycles
  • Wake the neonate slowly, gently

Protect sleep states by minimizing noise and light

  • Talk in a “library voice”
  • Avoid direct light with sleeping babies

Group interventions/ Cluster Care

  • Perform care with the baby not to the baby
  • Monitor the infant’s ability to self-calm

Facilitate Skin-to-skin Contact 

  • Promotes the most optimal sleep cycles

Ok we know sleep is important, we know how to protect it, but how do we know if our interventions are working? How do we assess our patient’s sleep-wake cycling maturation?  With neuromonitoring, of course! You can hear more about assessing sleep-wake cycles from Kathi in her aEEG Mastery Course.  Access that and more with our NEW Continuing Education Club!

Graven, S., & Browne, J. (2008). Sleep and brain development: the critical role of sleep in fetal and early neonatal brain development. Newborn and Infant Nursing Reviews, 8(4), 173-179.

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