Diabetes, high blood pressure and obesity through sleep with light - healing practice

How night light affects health

When older people are exposed to a light source while they sleep, it appears to be associated with a higher likelihood of obesity, diabetes, and high blood pressure. The light must therefore be turned off urgently at night.

A new study involving researchers from Northwestern University examined whether exposure to light at night was associated with a higher prevalence of individual risk factors for cardiovascular disease in older adults.

The results were published in the English-language journal SLEEP.

Widely used artificial night light source

"Whether it's our own smartphone, turning on the television at night, or light pollution in a big city, we live in the midst of a large number of artificial light sources available around the clock," reports study author Dr. Minjee Kim of Northwestern University Feinberg School of Medicine in a press release.

Since older people are already at higher risk of developing diabetes and cardiovascular disease, the researchers wanted to know if there was a difference in the incidence of these diseases related to light exposure at night.

Analysis of cardiovascular disease risk factor profiles

The researchers looked at 552 adults between the ages of 63 and 84. They focused on profiles of cardiovascular disease risk factors. In addition, activity and light measurements were recorded over a period of seven days.

How were sleep and light exposure measured?

Light exposure was measured in the study using a device worn on the dominant wrist. In addition, the participants filled out a sleep diary each day, the team explains.

Many were exposed to night light

Experts found in the study that less than half of participants spent five hours a day in complete darkness. The remaining participants were exposed to at least some light even during the darkest five-hour period of the day, which is usually in the middle of nocturnal sleep.

Light exposure at night was associated with higher odds of obesity (multivariable adjusted odds ratio (OR) 1.82), diabetes (OR 2.0), and hypertension (OR 1.74) , but not hypercholesterolemia, report the researchers.

However, the new research is a cross-sectional study, so it's unclear whether obesity, diabetes and high blood pressure cause people to sleep with lights on, or whether light contributes to the development of these diseases. said the research team.

Why do you need a night light?

For example, people with such diseases may have to go to the bathroom in the middle of the night with the light on. Or people with diabetes and numb feet can leave a nightlight on to reduce their risk of falling. The researchers point out that there are various reasons people turn their lights on at night or leave them on at night.

Avoid exposing yourself to light while you sleep

"It's important for people to avoid or minimize light exposure during sleep," said study author Dr. Phyllis Zee. If possible, no lights should be left on at night. If it is necessary to leave the light on, for example to prevent falls, it should be as low as possible and close to the ground, experts advise.

Night light should be as far away from sleeping people as possible and should be orange, red or orange, as these colors are less stimulating to the human brain. According to the research team, the use of white or blue light should be avoided.

Shades can be installed or eye masks can be worn to prevent exposure to outside light. Also, according to experts, the bed should be installed in such a way that outside light does not shine directly on your face. (as)

Author and source information

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This text corresponds to the requirements of the specialized medical literature, medical guidelines and current studies and has been verified by health professionals.


Minjee Kim, Thanh-Huyen Vu, Matthew B Maas, Rosemary I Braun, Michael S Wolf, et al. : Nocturnal light in the elderly is associated with obesity, diabetes and hypertension; in: Sleep (published 06/22/2022), SLEEPNorthwestern University: Light during sleep in older adults linked to obesity, diabetes, high blood pressure (published 06/22/2022), Northwestern University

Important Note:
This article contains general advice only and should not be used for self-diagnosis or treatment. It cannot substitute a visit to the doctor.