Babies and the Sleep Cycle
Sleep. We can’t function without it. Our brains and bodies are designed to restore and replenish during a sleep cycle, helping us stay healthy and strong. With a newborn baby in the house, however, sleep becomes a rare and precious opportunity because baby sleep patterns are different than an adult’s.
Sleep cycle basics
In the past, it was generally believed that the brain shut off at night to rest. With the invention and use of the EEG (electroencephalogram) in the 1920s, it was found to be far from the truth. The brain is active in varying degrees during sleep, as it is the body’s way of repairing and maintaining health and function. The two main types of sleep are rapid eye movement (REM) and non-rapid eye movement (NREM).
Stages of the sleep cycle
Each night, our brain rolls through stages of sleep that make up an entire cycle. As the brain produces specific waves, it moves to the next sleep stage. For example, alpha and theta waves are produced during light sleep, delta waves during deep sleep. Adults and older children pass through each sleep cycle stage in sequence: Stage 1, 2, 3, 4, 3, 2, REM. We progress through a sleep cycle multiple times through the night, and with each subsequent cycle, REM sleep lasts longer and non-REM is shorter.
- REM (Rapid Eye Movement) – A light, active sleep characterized by quick, darting eyes. This is the stage where dreams occur.
- Stage 1 – Correctly described as drowsiness, stage 1 sleep is very brief. Though dozing, you would be easily woken.
- Stage 2 – Light sleep during which there is still muscle movement. You may startle when there are sudden noises.
- Stage 3 – Deep sleep that makes it more difficult to awaken from. In stage 3 sleep, one is usually quiet and still, although when sleepwalking occurs, it is usually during this stage.
- Stage 4 –The most restorative of the sleep stages, stage 4 is when our bodies repair tissue, build up energy for the next day, boost the immune system, and undergo growth. No eye or other muscle movement happens during stage 4 sleep and the body is least responsive to stimuli.
Quality sleep is especially crucial for the growth of babies and children as the body produces growth hormone during sleep. Infants begin experiencing the sleep patterns during the last few months of pregnancy. Once born, babies still pass through each of the sleep stages, but there are some differences. Infants spend much more time in REM, averaging around 50% of sleep time in this active sleep; adults typically spend only 20-25% in REM. Babies also complete a sleep cycle in a shorter length of time than do adults. Basically, each baby is born with the biological instinct to sleep lightly and wake up more frequently than adults. After only 2-6 months, a newborn baby shows patterns of nocturnal sleep and fully developed NREM sleep stages.
Each child may have sleep patterns that differ from another. Some fall asleep quickly, others toss and turn for 20 minutes before succumbing to sleep. Many have most of their sleep in a longer chunk of time at night, while some take long naps during the day and sleep a little less during the night. If your child is getting the recommended amount of sleep and not showing signs of fatigue during the day, he is probably getting plenty.
When did your baby begin sleeping consistently through the night? Share in the comments!