Light exposure when sleeping is associated with high blood pressure, diabetes, and obesity in older persons


According to a recent study, those who were exposed to any level of light when sleeping at night had a markedly increased risk of being obese, experiencing high blood pressure, and developing diabetes.

Over the course of seven days, light exposure was assessed using a wrist-worn device.

The incidence of any nighttime light exposure being connected to increased obesity, high blood pressure (also known as hypertension), and diabetes among older persons is shown in this real-world (not experimental) study. It will be released in the journal SLEEP on June 22.

“We live among an abundant number of artificial sources of light that are available 24 hours a day, whether it be from one’s smartphone, leaving a TV on overnight, or light pollution in a big city,” said study corresponding author Dr. Minjee Kim, assistant professor of neurology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine physician. We sought to determine whether there was a difference in the frequency of these diseases associated to nighttime light exposure because older persons are already at increased risk for diabetes and cardiovascular disease.

Less than half of the 552 study participants regularly saw a five-hour period of total darkness each day, which astonished the study’s researchers. Even during their five darkest hours of the day, which were typically in the middle of sleep at night, the other participants were exposed to some light.

Researchers are unsure of whether obesity, diabetes, and hypertension induce people to sleep with a light on or if the light contributes to the development of these disorders because this was a cross-sectional study. With the light on, people with these conditions may be more prone to use the restroom in the middle of the night or for other purposes. A night light may be left on by a diabetic who experiences foot numbness to lessen the chance of falling.

Dr. Phyllis Zee, chief of sleep medicine at Feinberg and a physician with Northwestern Medicine, is a senior research co-author and stressed the need of avoiding or reducing light exposure during sleep.

Zee and colleagues are thinking of conducting an intervention research to see if restoring the natural light-dark cycle has a positive impact on health outcomes like cognition.

Zee suggested the following advice for minimising light exposure when sleeping:

Don’t switch on the lights. If you must have a light on—something that older people may need for safety—make it dim and closer to the floor.

Color is crucial. The brain receives less stimulation from amber or red/orange lights. Avoid using white or blue light, and keep it a far way from the individual who is sleeping.

If you can’t regulate the outside light, blackout shades or eye masks are good options. Reposition your bed so that the exterior light is not in your face.