Dr. Minjee Kim, an assistant professor of neurology at Northwestern University Feinberg School of Medicine, said the risks of light exposure from such devices were under-recognized.
“Our study suggests that light exposure before bedtime may be an easily modifiable risk factor of gestational diabetes,” Kim, the lead study author, said in a Northwestern article.

“Gestational diabetes is known to increase obstetric complications and the mother’s risk of diabetes, heart disease, and dementia. The offspring also are more likely to have obesity and hypertension as they grow up.”
Gestational diabetes occurs during pregnancy and is a complication that usually goes away after the baby is born but carries significant risks for both mother and offspring.
Researchers found that women with gestational diabetes are almost 10 times more likely to develop Type 2 diabetes than those who don’t have glucose issues during pregnancy.
Overstimulated Nervous System
Kim and her colleagues gave 741 women wrist-worn devices to measure their light exposure during their second trimester of pregnancy, the time when they receive routine screening for gestational diabetes.They discovered that light exposure before bedtime caused overactivity of the sympathetic nervous system, meaning that the heart rate goes up before bed, when it should go down.
Anxiety, nervousness, insomnia, inability to relax, and poor digestion are just a few signs of an overstimulated nervous system.
“It seems there is inappropriate activation of the fight or flight response when it is time to rest,” Kim said.
Overexposure
Bright lights in the home and from devices such as televisions, computers, alarm clocks, and smartphones should be avoided for three hours before going to bed, according to Kim.“We don’t think about the potential harm of keeping the environment bright from the moment we wake up until we go to bed,” she said.
“But it should be pretty dim for several hours before we go to bed. We probably don’t need that much light for whatever we do routinely in the evening.
“But if you have to use them, keep the screens as dim as possible.”
Kim suggested that people use the night light option and turn off the blue light.

Optimizing the Circadian Rhythm
According to modern research and traditional Chinese medicine, synchronizing one’s daily activities with the day’s cycles of light and dark can regulate one’s circadian rhythm, influencing important functions in the body, such as digestion and body temperature.However, unnatural signals from the environment also affect circadian rhythms.
This may explain why many studies have revealed that nighttime exposure to light causes the loss of the sleep hormone melatonin and, over time, weakens the immune system.

“Humans are genetically adapted to a natural environment consisting of sunlight during the day and darkness at night,” epidemiology professor Chandra Jackson said in a 2019 National Institutes of Health article.
‘Diabetes a Sign of Nutritional Inadequacy’
Diabetes can also be prevented with a nutrient-rich diet, according to Dr. Joel Fuhrman, a physician and internationally recognized expert specializing in preventing and reversing disease through nutritional methods.“Gestational diabetes is a sign of nutritional inadequacy. If you have gestational diabetes, the best medicine is no medicine.
“Who knows what subtle, long-term effects diabetes medications may have on an unborn child? Superior nutrition is the safest and most effective choice.”

While eating healthy, losing weight, and exercising can be effective, turning down the lights may be a quicker and easier way to lower the risk of developing diabetes.
“Now I’m the light police at home. I see all this light I never thought about before. I try to dim the light as much as possible,” Kim said.