Researchers at Northwestern University in Illinois have discovered a link between light exposure during sleep and obesity.

Want to stay slim? Turn your phone, TV and lights off before bed, scientists say

Do you want to stay slim? Turn off the phone, TV and lights before bed and sleep with a mask, scientists say

  • Northwestern researchers have found a link between light exposure and obesity
  • A study shows that 40.7% of people exposed to light before sleeping were obese
  • Only 26.7% of the group that was not exposed to light for five hours were obese

Turn off your phone, TV, and lights before bed if you want to stay slim.

Because scientists have once again discovered a link between light exposure during sleep and obesity.

The most recent, purely observational evidence does not show that bright flashes while your eyes are closed make you fat. But the evidence that nightlight stimulates weight gain is piling up fast.

Academics recommend that people wear masks at night and put blackout blinds on their windows, as well as turning off their devices.

And people who need a light on, such as the elderly, should only use a dim light close to the floor.

Researchers at Northwestern University in Illinois have discovered a link between light exposure during sleep and obesity.


Circadian rhythms last for around 24 hours.

They vary from person to person, which is why some people are ‘morning people’ and others are ‘night owls’.

Natural factors within the body produce circadian rhythms, as well as environmental cues such as daylight.

Irregular rhythms have been linked to several chronic health conditions, including sleep disorders, obesity, diabetes, and depression.

Light exposure suppresses the secretion of melatonin, a hormone that influences circadian rhythms and aids sleep.

Melatonin levels rise at night and remain elevated throughout the night, promoting sleep.

Artificial lighting and electronics with blue wavelengths trick the mind into thinking it’s daytime.

How can you reduce your exposure?

  • Use dim red lights, which have the least effect on melatonin, for night lights.
  • Avoid looking at bright screens two to three hours before bedtime.
  • If you work a night shift or use a lot of electronic devices at night, there are glasses and apps that can filter blue light.
  • Check if your phone settings have a night setting that automatically changes the screen to warmer colors at sunset.

Having a BMI over 30, defined as obesity, puts people at higher risk for type 2 diabetes, heart disease, and cancer.

About a quarter of adults are obese in England, but the prevalence is closer to 40 percent in the US, figures suggest.

Researchers at Northwestern University in Illinois followed 552 people, ages 63 to 84, in their study, published in the journal SLEEP.

Although the study only looked at older people, previous research has shown similar effects in younger generations.

Dr. Minjee Kim, a neurologist and author of the study, said: “Whether it’s from the smartphone, leaving a TV on overnight, or light pollution in a big city, we live among a plethora of artificial light sources that are available 24 hours a day.” day.’

Co-author Dr. Phyllis Zee, an expert in sleep medicine, said: “It’s important for people to avoid or minimize the amount of light exposure during sleep.”

All volunteers were asked to track their light exposure, including at night, for a week.

Less than half consistently had a five-hour period of darkness, much to the surprise of the researchers.

Next, Dr. Kim and his colleagues checked whether the participants were obese, had diabetes, or had high blood pressure to discover any links.

Results showed that 40.7 percent of people exposed to light within the five-hour period were obese, compared to 26.7 percent in the no-light group.

About 17.8 percent in the light exposure group had diabetes, twice as many as the other cohort (9.8 percent). A similar difference was found between groups in the rate of hypertension.

The differences were found to be significant when other potential risk factors were taken into account.

The study was observational, meaning the team couldn’t prove that light exposure was causing obesity, diabetes, or high blood pressure.

Experts believe, however, that falling asleep with the light on can confuse the biological clock. This could alter hormone levels, which have a side effect that can make people seek more food.

But other experts have claimed that the light emitted by Kindles and iPads is much weaker than natural light at dawn. They say the problem stems from the increased mental alertness required to use the devices.

More research is needed to show the long-term effects of late-night screen viewing on weight gain and its associated conditions, they said.


Leave a Comment

Your email address will not be published.