From little smiles to frowns, and fluttering eyes to twitches, the face of a sleeping baby is remarkably expressive. What happens during this time? Research exploring this question reveals much about the stages of sleep. However, it cannot definitively confirm whether babies dream during sleep.
Sleep Stages
Sleep is divided into two main stages: active sleep and quiet sleep. Active sleep, also known as rapid eye movement (REM) sleep, is characterized by rapid eye movements. Dreaming typically occurs during this stage. Quiet sleep, or non-REM sleep, consists of four phases: drowsiness, light sleep, deep sleep, and very deep sleep.
Newborns’ sleep patterns begin with a brief REM stage, progress through the four phases of quiet sleep, and return to REM sleep, restarting the cycle.
The Role of REM Sleep
The exact function of REM sleep remains debated, but its importance is widely recognized. Theories suggest REM sleep supports brain development, even in utero. Researchers attribute REM sleep to providing visual imagery that aids the mental development of the fetus.
This theory is supported by evidence showing that REM sleep decreases with age. Fetuses experience nearly 100% REM sleep, two-year-olds about 25%, adults around 20%, and the elderly approximately 15%. Essentially, babies receive more REM sleep to support rapid brain development. As brain development slows, REM sleep decreases, reaching near-adult levels by the toddler years.
REM and Dreams
Researchers confirm that older children and adults experience vivid dreams during REM sleep. However, some studies, including an Australian one, suggest newborns may not dream in the same way. The brain region active during adult REM sleep shows less activity in newborns, leading researchers to question whether newborns dream as adults do.
Despite this, because infants spend significant time in REM sleep, many believe they dream similarly to adults. Some propose that babies in utero dream about the light they see and sounds they hear, such as heartbeats, voices, or music. After birth, their dreams are likely shaped by the diverse sensory stimuli they encounter.
REM and Wakefulness
Babies spend more time in REM sleep and, until about three months of age, must pass through an REM phase before entering quiet sleep. This increased REM sleep heightens the likelihood of babies waking during the night as they transition between sleep stages. Parents of sleepless newborns may find comfort in knowing this is a biological norm, not a medical issue, as babies navigate these sleep cycles.
Babies and Bad Dreams
Research and anecdotal evidence indicate that nightmares, or “bad dreams,” are most common between three and five years of age. However, many parents and pediatrician Dr. Alan Greene disagree, noting that newborns often wake with loud cries suggestive of distress.
Dr. Greene believes babies can experience nightmares. Stressors like pain, hunger, or being left alone can cause tears, and as Dr. Greene states, “…anything worth crying about is worth dreaming about.” He suggests that babies’ brains process both pleasant and unpleasant experiences through dreams.
Sleep Like a Baby?
With frequent waking, brain development, REM, non-REM, and the possibility of dreaming, an infant’s sleep is a busy time. All this activity makes one question the origin of the phrase “sleep like a baby,” doesn’t it?
