Even a Little Light in Your Bedroom Could Harm Health

TUESDAY, March 15, 2022 (HealthDay News) —

People who sleep in the light may unwittingly keep their nervous systems awake, a small study suggests. Study of 20 healthy adults found that just one night of sleep with the lights on caused changes in people’s functioning: their heart rate remained higher during sleep compared to a night with the lights off. And by the next morning, they were producing more insulin, the hormone that regulates blood sugar levels.

The effects were not dramatic. But it’s likely that small effects night after night could eventually affect human health, says senior researcher Dr. Phyllis Zee. “This study doesn’t prove it, and we need more research to look at chronicity,” said Zee. Head of sleep medicine at Northwestern University’s Feinberg School of Medicine in Chicago. But at the same time, she says, there is a slight downside to dimming the lights before bed. “I don’t think people need to sleep in total darkness,” Zee said. She noted that even our non-technological ancestors were exposed to moonlight.

So if you need a night light for safety, Zee said, that’s fine.

Just make it less bright and place it closer to the floor. Zee added that light at the red/amber end of the spectrum is better than white or blue. Because it stimulates the brainless. It is well known that people need sunlight during the day. And darkness at night to keep their bodies healthy. circadian rhythms works optimally. These rhythms, similar to a 24-hour internal clock, help regulate processes throughout the body. Including sleep, metabolism, and hormone release.

But modern humans are exposed to all kinds of artificial light at night, and research points to pitfalls. Exposure to blue light from glowing devices can be especially problematic. It suppresses the body’s release of the sleep hormone melatonin, making us feel more alert when we need to relax. According to Zee, there has been less research done on the potential exposure to artificial light while sleeping.

So she and her colleagues recruited 20 healthy young adults to study in the sleep lab.

The tenth spent two nights in a row, falling asleep only by the dim light of a nightlight. The other 10 had dim lighting one night, but slept with the overhead lights on the second night — enough to light up the room with a moderate amount of light, Zee said. On average, this light-on condition caused a slight increase in heart rate in the volunteers, as well as a decrease in their heart rate variability (bad), the researchers found. It also made their bodies more resistant to the effects of insulin the next morning. insulin resistance persists, maybe a precursor to type 2 diabetes.

“This provides a biological possibility that exposure to night light could potentially increase the risk of diabetes and other cardiovascular diseases,” said Dr. Kannan Ramar, former president of the board of directors of the American Academy of Sleep Medicine. The study does not prove this, but emphasized Ramar, who was not involved in the work. But he agreed that it was wise to keep the bedroom lights dimmed and the TVs and phones away from the bed.

It’s not that the study volunteers were bothered by the light.

“They thought they slept well,” Zee said. Light did not disrupt melatonin levels in humans. Instead, Zee says, the effect of light on heart rate and insulin levels suggests that light activates the sympathetic nervous system, which keeps us awake and is normally activated during the day. Research – published online March 14 in the journal proceedings of the National Academy of Sciences not the first to suggest the harm of sleeping with the lights on.

BUT 2019 study of women in the US found that those who slept with lights on or the TV on were more likely to gain weight over time and be more obese than those who slept without lights. But there are few laboratory studies to look for potential mechanisms, says Matt Lehrer, an associate professor at the University of Pittsburgh who studies sleep and circadian rhythms.

He called the new study “a good step forward.”

Future research, Lehrer said, could include people who already have insulin resistance and high blood sugar to see if having the lights (or the TV on) on makes sleep worse. Lehrer noted that compared to other lifestyle factors such as diet and exercise, less is known about the health effects of light. But, he says, people need to know that it matters. Zee agreed and noted that getting sunlight during the day is just as important as limiting artificial lighting at night.

More information

The Sleep Foundation has more information on light and sleep.

SOURCES: Phyllis Zee, MD, chief of sleep medicine, Northwestern University, M.D. Feinberg, Chicago; Matt Lehrer, PhD, associate professor of psychiatry at the University of Pittsburgh; Kannan Ramar, MD, former President of the American Academy of Sleep Medicine, Darien, Illinois, and Professor, Department of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, Minnesota; Proceedings of the National Academy of Sciences, March 14, 2022, online

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *