Do you want to stay slim? Scientists say: Turn off your phone, TV and lights before bed and sleep with a mask
- Northwestern University researchers have found a link between light exposure and obesity
- The study showed that 40.7% of people who were exposed to light before bed 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 you go to bed if you want to stay slim.
Scientists have discovered, once again, a link between exposure to light during sleep and obesity.
The latest evidence, purely observational, does not prove that bright flashes while your eyes are closed make you fat. But the evidence that light at night fuels weight gain is accumulating quickly.
Academics advise people to wear masks at night and install blackout curtains on their windows, as well as turn off their devices.
And people who need light – such as the elderly – should use only dim light near the ground.
Researchers at Northwestern University in Illinois have revealed a link between exposure to light during sleep and obesity
How does light affect sleep and what can you do?
Circadian rhythms are approximately 24 hours long.
They differ 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 signals such as daylight.
Irregular rhythms have been linked to many chronic health conditions, such as sleep disturbances, obesity, diabetes and depression.
Exposure to light inhibits the release of the hormone melatonin, which affects circadian rhythms and aids sleep.
Melatonin levels rise in the evening and stay high throughout the night, promoting sleep.
Artificial lighting and electronics with blue wavelengths trick the mind into thinking it is 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 bed.
- If you work a night shift or use a lot of electronic devices at night, there are glasses and apps that can filter out blue light.
- Check if your phone settings have a night setting that automatically turns your display into warmer colors at sunset.
Having a body mass index above 30 — defined as obesity — puts people at greater risk of developing type 2 diabetes, heart disease and cancer.
Nearly a quarter of adults are obese in England, but the prevalence of the disease is closer to 40 percent in the United States, the figures suggest.
Researchers at Northwestern University in Illinois tracked 552 people between the ages of 63 and 84 in their study published in the journal SLEEP.
Although the study only looked at older adults, previous research has shown similar effects in younger generations.
Neurologist Dr. Minji Kim, author of the study, said: ‘Whether it’s from a smartphone, leaving the TV on all night or light pollution in a big city, we live among a plethora of artificial light sources that are available 24 hours a day. day.’
“It is important that people avoid or reduce the amount of exposure to light during sleep,” said study author Dr. Phyllis Zee, an expert in sleep medicine.
All volunteers were asked to track their exposure to light – including at night – for a week.
Less than half had a five-hour period of darkness, to the researchers’ shock.
Dr. Kim and his colleagues then examined whether the participants were obese or had diabetes or high blood pressure to detect any connection.
The results showed that 40.7 percent of the people exposed to light during 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, double that of the other group (9.8 percent). A similar difference was found between groups when it came to 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 was unable to prove that exposure to light causes obesity, diabetes or high blood pressure.
Experts believe, however, that sleeping with light may confuse the body clock. This can disrupt hormone levels, which has an indirect effect that can cause people to seek out more food.
But other experts have claimed that the light emitted by Kindles and iPads is much weaker than the natural light at dawn. They say the problem stems from the increased mental alertness required to use devices.
They said more research is needed to establish the long-term effects of staring at screens at night on weight gain and its associated conditions.