Nightlights That Help You Sleep May Also be Killing You

Many people who struggle to fall asleep turn to nightlights. It gives people a sense of safety and helps them rest their tired eyes. However, a recent study found that even s small amount of light throws your body out of sync.

Light and Sleep: How Nightlights are Killing You

(Photo: Photo by cottonbro)

Many believe that the reason why a person's heart races are stress. However, another culprit could be your night light. As it turns out, even a small amount of ambient light from your TV, nightlight, or even exterior light that filters through your bedroom window at night can negatively impact your health, according to a recent study published in the journal Proceedings of the National Academy of Sciences, titled "Light exposure during sleep impairs cardiometabolic function."

Chief of sleep medicine at the Northwestern University Feinberg School of Medicine, Phyllis Zee, says that the results of the study show that just a single night of exposure to a moderately lit room during sleep can impair a person's glucose and cardiovascular regulation, risk factors for diabetes, heart disease, and metabolic syndromes.

According to a press release, researchers monitored participants that slept in moderately lit rooms of 100 lumens per square meter and compared them to those that stayed in dimly lit rooms, of three lux, throughout one night and analyzed how the participant's bodies adjusted throughout the night and into the next day.

Participants that slept in moderately lit rooms went into a heightened state known as sympathetic activation. The autonomic nervous system, charged with regulating heart rate, body temperature, pupil dilation, and digestion, splits into two systems, the sympathetic and parasympathetic nervous systems. During the day, the body's sympathetic nervous system regulates various functions that help the body prepare for activities and governs the body's response to stress. At night, the parasympathetic nervous system aids the body in digesting, recuperating, and resting.

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Detrimental Effects of Light During Sleep

The additional light in the participant's room triggered the sympathetic nervous system, which at the time should have been inactive, and kicked into overdrive. Participants in the moderately lit room experienced elevated heart rates and a spike in how the heart forcefully contracts throughout the night.

Additionally, the following day, participants in moderately lit rooms showed signs of insulin resistance. This means that the cells in the participant's muscles and fat began to reject insulin and couldn't process glucose properly to make energy. Over time, the spike in insulin resistance may lead the pancreas to produce more insulin and eventually lead to higher blood sugar levels or type-2 diabetes, explains the authors.

Zee explains that the study's findings are vital, especially for people living in modern societies where exposure to both indoor and outdoor nighttime light has become increasingly widespread. He adds that if a person can see things clearly, it's probably too well lit, reports PopularMechanics.

Some options to get better sleep are installing blackout curtains, wearing eyemasks, or rearranging the room's furniture to blackout unnecessary lighting.