A study found that even low levels of light can disrupt sleep and increase the likelihood of developing serious health issues such as diabetes, high blood pressure, and obesity among older adults.
The journal SLEEP published the findings of the research.
According to a Northwestern Medicine study, older people ranging in age from 63 to 84 were significantly more likely than adults to be exposed to light while they slept at night to experience obesity and high blood pressure.
The light exposure was measured using a wrist-worn device, and the data was tracked for seven days.
This is an actual-world (not experimental), study that shows how light exposure at night can be linked to obesity, high blood pressure (known under hypertension), and diabetes among older adults. The study will be published in the journal SLEEP on June 22.
“Whether it’s from one’s smartphone, a TV left on overnight, or light pollution in big cities, we live amid an abundance of artificial light sources that are available 24 hour a day,” Dr Minjee Kim, Northwestern Medicine physician and assistant professor of neurology, said. “We wanted the study to determine if there were any differences in the frequency of cardiovascular disease and diabetes among older adults.
Researchers were surprised to see that only half of 552 participants experienced five hours of complete darkness per night. The remaining participants were exposed even to some light during their darkest five hour periods, which were typically in the middle or late of their nights at night.
The investigators are unsure if this cross-sectional study revealed if obesity, hypertension, or diabetes causes people to sleep with a light on.
People with these conditions are more likely to use the toilet in the middle or late of the night (with the lights on), or they may have other reasons to keep the lights on. A night light may be helpful for diabetics who have foot numbness.
Dr. Phyllis Zee (chief of sleep medicine at Feinberg, Northwestern Medicine physician) said that it is important that people avoid or minimize light exposure while sleeping.
Zee and her colleagues are currently preparing an intervention study in order to see if restorations of the natural light/dark cycle will improve cognition and other health outcomes.
Zee gave tips on how to decrease light while sleeping:
Do not turn on the lights. You can have a dimming light, but it should be closer to the floor if you are requiring it (which may be desirable for safety reasons).
It is important to use colour. Red/orange and amber light are less stimulating for the brain. Avoid using white or blue light, and keep it away from the person sleeping.
Blackout shades or eye masks work well if the outdoors light is too strong. You can move your bed to make sure the outside light doesn’t shine on your face.