Baby Talk | You have a sleep cycle, but when baby arrives, everything changes

Babies do not have a circadian rhythm. Unfortunately mothers do.

The term circadian was coined by a German biologist, Franz Halberg, in 1959. It comes from the Latin word circa, which means about, and the Latin word diem, which means day. Essentially it refers to the changes which occur in an organism over a 24-hour period, or a daily cycle.

We humans, as do many other animals and even plants, have a biological clock. Some flowers will open their bloom in the morning and close at night. That is their circadian rhythm based on their innate timing device, or biological clock. A biological clock is an organism’s innate timing device.

Our biological clock produces a circadian rhythm that regulates our timing reaction to differences in our reaction to light and darkness in our environment. This master clock is in our brain. It is composed of around 20,000 nerve cells in the hypothalamus area of our brain. The hypothalamus receives input from our eyes. Our eyes receive the message of darkness and light. The hypothalamus takes the message and directs then our circadian rhythm.

The brain is active during sleep. The brain’s trillions of cells are literally rewiring themselves. The brain is making a map of information, making new connections and breaking other ones.

An organism’s circadian rhythm develops over time. Babies have brains which are learning how to live outside the womb. Their hypothalamus in the first few months has not developed to the point where it sends a message differentiating darkness and light. Their brains are still making connections, or synapses. They are growing at warp speed.

They have nutritional needs that need to be met every few hours as they are growing rapidly in the first six months. So they do not sleep all night and remain awake all day. They are incapable of doing that.

The whole sleep/wake thing is also affected by hormones. We know the adrenal gland is also directed by the hypothalamus. The hypothalamus sends a message to the pituitary gland, also in the brain, to send a message to the adrenal glands to release cortisol. Cortisol then gives us the energy to get up and proceed through our day.

As the biological clock ticks away and our energy fades the pineal gland releases melatonin, the sleep hormone. Darkness prompts the pineal gland to start producing melatonin while light causes the production to stop. That is how our circadian rhythm is controlled by our biological clock.

Babies change everything.

When a new baby enters a family one of the biggest impacts is the toll on interrupted sleep. Sleep deprivation can lead anxiety and depression, compromised immune systems, inability to process thoughts and being in a bad mood … which then affects relationships.

There are sleep stages. Basically rapid eye movement (REM) sleep and non-REM sleep, which has three different stages. Each is linked to specific brain waves and neuronal activity. We cycle through all stages on non-REM and REM sleep several times a typical night. These cycles typically last around 90 to 120 minutes.

Interestingly, babies sleep around that long between feedings. Their brains are not wired yet to go through multiple cycles of stages. Their tummies are small. So when they finish a sleep stage they will wake up, feed and then go back into another sleep stage.

The first few months with a new baby are hard. There are many challenges and sleep deprivation is one of the most challenging. I promise you, it will get better!

Katie Powers, R.N., is a board-certified lactation consultant and perinatal educator at Manatee Memorial Hospital’s Family BirthPlace. Her column appears every other week in Healthy Living in the Bradenton Herald. Contact her at katie.powers@mmhhs.com.