Dimming lights 3 hours before sleep is better for health

Scientists are advising pregnant people to turn off or dim the lights in
their homes a few hours before bedtime to reduce the risk of developing
gestational diabetes mellitus.The lights in question also include those
coming from computer monitor and smartphone screens, according to the
research from Northwestern Medicine, Northwestern University, US. Women who
developed gestational diabetes mellitus in the multi-site study had greater
light exposure in the three hours before sleep onset, the study said. They
did not differ in their light exposure during daytime or sleep or in their
activity levels compared to those who did not develop it.
“Our study suggests that light exposure before bedtime may be an
under-recognized yet easily modifiable risk factor of gestational
diabetes,” said lead study author Minjee Kim, assistant professor at
Northwestern University. Growing evidence suggests exposure to light at
night before bedtime may be linked to impaired glucose regulation in
non-pregnant adults. Bright light exposure prior to sleep can come from
bright lights in your home and from devices like TVs, computers and
smartphones. However, little is known about the effect of evening light
exposure during pregnancy on the risk of developing gestational diabetes, a
common pregnancy complication with significant health implications for both
the mother and the offspring.
The study, believed to be one of the first multi-site studies to examine
light exposure before sleep on the risk of developing gestational diabetes,
is published in the American Journal of Obstetrics and Gynecology Maternal
Fetal Medicine.