Melatonin and serotonin are hormones that regulate sleep, mood and appetite. The two hormones work together, and they cannot be produced simultaneously. Serotonin is produced in the sunlight, and melatonin is produced in the dark. Melatonin makes us feel sleepy, and specifically, is responsible for regulating circadian rhythms, which allows the body to control sleeping patterns, the release of hormones and body temperature.
Light and sleep:
Exposure to light triggers a response of the SCN in the hypothalamus, which tells the body it is time to wake up. This occurs due to an automatic set of events that happen when the body is exposed to bright light first thing in the morning. This process helps to regulate when your baby will have natural dips in alertness that make it easier to fall asleep and stay asleep soundly. Light from the sun, artificial indoor light, light from screens or nightlights can block the production of melatonin.
Melatonin at birth
Newborns are typically very sleepy in the first few weeks, and this is because they have a surge of maternal melatonin from their mother at birth, and it is fine to have them sleep in the bright light at this point, as it will help them to learn the difference between night and day. Following this, babies tend to ‘wake up’ and begin to have irregular sleeping patterns. This is because they are not producing their own melatonin yet, nor do they have a functioning circadian rhythm. Melatonin and serotonin are produced in the pineal gland in the body, and when baby is born, their pineal gland is immature, and does not produce these hormones.
The beginning of melatonin production and how it affects sleep
Between the 8th and 12th week (or 8th to 12th week corrected in premature babies), your baby’s pineal gland is mature enough to start producing their own melatonin, and because of this, your baby’s circadian rhythm will begin to function. This is when you will start to see cat napping appear – baby will nap for 40-50 minutes at a time, and this is one sleep cycle. It is important to teach baby how to join these sleep cycles together at this point to avoid frequent night waking as baby’s circadian rhythm matures. Allowing baby to sleep in the dark for all naps and night sleep is crucial from this point onwards, as melatonin production will not occur unless they are in the dark, and they won’t be able to begin joining their sleep cycles together unless they have adequate levels of melatonin and also avoid the trigger of light that makes them wide awake.
Ways we can create a dark environment
When we are creating a dark environment for your baby to sleep in, we need it to be very dark – 8 or 9 out of 10, if 10 is pitch black. You definitely should not be able to read a book in your baby’s room. At home, the easiest and cheapest way to make baby’s sleep environment dark is by putting aluminum foil on the windows. You can also purchase specially designed black out blinds for this purpose, or fabric to make your own. Roller shutters on the outside of the windows also create a perfect level of darkness. When you are out and about, cover the pram with a dark coloured muslin swaddle, or use a hood on your baby carrier.
Foods that support melatonin production
There are also foods that will aid in the production of melatonin and serotonin and can help to support your child’s sleep. Foods that are rich in tryptophan and B vitamins like poultry, natural nuts, bananas, kidney beans, eggs and dairy products will encourage healthy melatonin and serotonin production.
Owner and founder of Baby Sleep Consultant Australia