What is sleep?
In itself this may seem like a simple question, but as is more often the case with simple questions, there is no simple answer. Sleep has been described as a “the natural, easily reversible periodic state of many living things that is marked by the absence of wakefulness and by the loss of consciousness of one’s surroundings.
People need sleep, that’s for sure. It is a requirement for the body and mind to recover from the day. The body produces more new cells and antibodies during sleep than when someone is awake.
What happens during sleep?
Well, a lot happens in our body during sleep:
- brain activity changes;
- body temperature drops (about 1 degree Celsius/2 degrees Fahrenheit);
- the heart rate slows down;
- less air is inhaled;
- less saliva is produced;
- less urine is produced;
- the amount of growth hormones increases;
- the amount of stress hormones decreases.
Stages of sleep: The sleep cycle
All babies still sleep a lot during the first period after birth. It is difficult to say exactly how much, it varies per child and per day. It is possible to predict somewhat what the sleep pattern of a healthy baby born on time will look like compared to an adult. The sleep cycle (from deep to light sleep) takes approximately:
- 90/120 minutes in adults;
- 45 minutes in newborns
- 50 minutes in babies between 3 to 8 months.
The 5 stages
The sleep cycle has 5 stages. Stage 1,2,3, and 4, are categorized as ‘non-REM sleep’, and the 5th stage, is REM sleep. Everyone usually wakes up briefly after each cycle. Your body checks whether there are no pain stimuli, whether your bladder is too full and whether the environment is safe. If something is wrong, you wake up to take action. If everything is okay, you go back to sleep and the cycle starts again.
Non-REM Sleep of the Sleep Cycle
Stage1: Stage of falling asleep. You float between waking and sleeping. Your eyes close, brain activity decreases. (This stage takes a few minutes in adult’s sleep).
Stage 2: light sleep. You are asleep, but not yet in deep sleep. You no longer wake up from every sound, but when you do wake up, you don’t feel like you slept well yet. (This phase lasts just under an hour n adult’s sleep).
Stage 3: the transition phase to deep sleep. Your breathing becomes regular, your heart rate drops and your muscles relax. (This phase takes about 5 minutes in adult’s sleep.)
Stage 4: deep sleep. When you wake up now, you feel confused and need time to realize where you are. This phase lasts a little less than 20 minutes (in adult’s sleep) and provides physical rest.
Stage 5: REM sleep. REM sleep follows deep sleep and is also called ‘dream sleep’. REM stands for Rapid Eye Movement because the eyes are constantly moving during this phase. During REM sleep, data processing takes place and certain things are stored in our long-term memory. It is also the emotional recovery phase. Your body is completely at rest and your brain is running at full speed. This phase lasts approximately 20 minutes in adult’s sleep. You will usually wake up afterwards, but too short to remember before the new cycle starts again.
Babies often sleep for periods of 45 or 50 minutes or a multiple thereof. So they sleep for 45 to 50 minutes, 90 to 100 minutes, 135 to 150 minutes or 180 to 200 minutes before they wake up again. The depth of sleep also varies; the ratio of deep and light sleep is as follows:
- adults have 80 percent deep sleep and 20 percent light sleep ;
- full term babies have 50 percent deep sleep and 50 percent light sleep
- premature babies 20 percent deep sleep and 80 percent light sleep
This partly explains why little ones are more often awake at night than their parents. It can take a while for a baby to sleep a little longer during the night. In children aged 3 years, sleep cycles are about 60 minutes. By about 5 years, sleep cycles have matured to the adult length of about 90 minutes.
Sleep problems at night
Children have a lot of deep sleep directly after they fall asleep. That’s why children sleep so soundly after they’ve gone to bed. Children have more light sleep (REM and light non-REM sleep) in the second half of the night. Children then wake more easily, while it’s harder to fall back asleep at that moment. Especially children who havent learned to fall asleep independently will wake up more often and need their parents help to fall back asleep. If your child is waking up at night and you could use some advice, leave a message or email me at email@example.com. I’d be glad to help!