If you are a parent, you know how difficult it is to get a toddler to go to bed at night. They resist bedtime and have difficulty falling to sleep. For your part, you are probably exhausted and feel desperate to have them fall asleep at a decent time so you can get just a few moments to yourself. 

Or perhaps your babies are no longer babies. Instead, you have teenagers who stay up way too late night after night, then struggle with getting up in the morning and leave for school feeling groggy.

While sleep difficulties and disorders are complex and are the result of multiple factors, artificial light at night plays a significant role in these struggles.


Children Sleep

Let’s begin with an overview of some of the power players when it comes to the ability of humans to sleep. We often refer to melatonin as the sleep hormone, because it is what makes us feel sleepy every day. 

When the sun rises on a new day, that light touches receptors on our skin and enters the retina of our eyes. These light receptors send a signal to the body that it is daytime and that melatonin is no longer needed. So our melatonin levels drop dramatically and we have very little of it pumping through us in the morning. 

We can get a little spike of it in the afternoon, causing us to feel drowsy and wishing for a nap.

But as the sun sinks lower in the sky, those light receptors notice that the light is diminishing and notifies the melatonin “factory” in our bodies to begin production. All evening, melatonin is building. After the sun goes down, melatonin begins a steep climb, making us feel more and more sleepy until we finally go to bed. Then it keeps us asleep until we cycle back around to sunrise again.

It sounds smooth and easy, but there are things that can interfere with our natural production of melatonin. Artificial light at night is a significant factor.


Children Sleep

Science has shown that children’s eyes let in more light than the eyes of an adult. And light plays a powerful role in the body’s biological clock or circadian rhythm. 

Lameese D. Akacem, an instructor at the University of Colorado, Boulder, was the lead author of a study that measured melatonin levels in children. 

The study showed that when children were exposed to bright light before bedtime, they experienced a dramatic reduction of melatonin. Even leaving their dark bedroom after going to bed and going into a lit room to see their parents for a minute or two had an enormous impact.

They discovered that the average bedtime for kids in the study, who were ages 3-5, was 8:27 PM. But those who were given a dim, low-light “cave” experience before bedtime began secreting melatonin on average at 7:47 PM. In other words, their “biological night” began much earlier when they were not exposed to bright light.

In the experiment, researchers had the children play on light tables before bed the night after experimenting with the cave-like environment before bed. Their melatonin levels were 90% lower when they played at the light tables before bedtime.

Bedtime resistance and sleep problems are common at this age, so this study might encourage parents to pay attention to the evening environment they provide their kids. Helping their kids stay in tune with their natural circadian rhythms might result in a better bedtime experience. And what parent doesn’t want that?

But toddlers are not the only children who are heavily impacted by artificial light at night.


Children Sleep

A recent study shows that teens who live in areas with high amounts of outdoor artificial light get less sleep and experience higher rates of mood disorders than those who live in darker locales.

In this study, researchers looked at the long-term effects of light pollution on the mental and physical health of teens.

Although the study acknowledges light pollution and artificial light at night are only one factor in a list of complexities when it comes to sleep and teens, it also shows that light is an important factor.

The disruption to sleep caused by light pollution is linked to high blood pressure, a weakened immune system, weight gain, a lack of libido, and a higher risk of diabetes, stroke, cardiovascular disease, dementia, and some cancers. It can also lead to certain mental disorders, including bipolar disorder, mood swings, paranoia, and anxiety.

Teens need about nine hours of sleep at night, but screen time, long hours of homework, or working late at a job, all contribute to habits of going to bed late. Most school districts have high school students starting classes as early as 7:00 AM, with many teens driving to school drowsy.

According to a Sleep in America poll, more than 90% of high school students in the United States are chronically sleep-deprived and 20% are getting less than five hours of sleep at night.

These studies found that teens who lived in cities with higher levels of light pollution and artificial outdoor lights go to bed later and sleep less. They had higher levels of mood and anxiety disorders, especially bipolar disorders.


You can help your kids get a better night’s sleep by creating an environment that promotes the natural production of melatonin in the early evening through bedtime. This environment will be beneficial for the entire family, reducing the risk of certain diseases, mental disorders, and sleep disorders.