Night-time Light Exposure Increases Type 2 Diabetes Risk

From diatribe.org

Key takeaways:

• Exposure to bright light at night can increase the risk of developing type 2 diabetes by up to 67%, a study reported. 
• That’s because nighttime light causes disruptions in the body’s circadian rhythms, which can affect insulin production and blood sugar regulation.
• Simple steps can help reduce the risk, including powering down electronics and turning off overhead lights before sleep.

Type 2 diabetes prevention often involves lifestyle changes like regular exercise and eating nutritiously, but there’s another easy tactic you might not know about: cutting out light at night.

A new study reports that people exposed to bright light at night are at greater risk for type 2 diabetes. In the study, roughly 85,000 people without diabetes wore wrist sensors for a week to measure light during the day and night. Researchers followed up with participants over nine years to see if they developed type 2 diabetes and found that exposure to bright light between 12:30 a.m. and 6 a.m. made people significantly more likely to develop the disease.

Researchers also found the risk was dependent on the amount of light exposure. Those exposed to more light at night were 28% to 67% more likely to develop type 2 diabetes. The good news is, cutting out night-time light is an easy (and cost-effective) step you can take to reduce your risk.

Why does light at night increase diabetes risk?

Circadian rhythms are the physical, mental, and behavioural changes the body goes through over a 24-hour period. And irregular sleep has been linked to increased risk of chronic conditions.

"It is thought that these poor health outcomes are related to disruption of the body’s circadian rhythms," said senior author Andrew Phillips of the College of Medicine and Public Health at Flinders University. "The central circadian clock’s rhythms – both their timing and strength – are regulated almost entirely by light."

Circadian rhythm disruptions can lead to changes in insulin secretion and glucose metabolism, Phillips said. This affects the body's ability to regulate blood sugar levels, which can lead to the development of type 2.

Even after other factors like lifestyle, sleep patterns, diet, and mental health were taken into account, researchers still found a connection between nighttime light exposure and type 2. Chelsie Rohrscheib, a neuroscientist and head sleep expert at Wesper, a sleep test company, said she wasn't surprised by the study results. 

"Chronically poor sleep quality and reduced sleep time lead to insulin resistance and glucose intolerance, as well as increased cortisol levels, appetite and inflammation – all key factors in the development of type 2 diabetes," Rohrscheib said. 

Tips for reducing light at night 

Rohrscheib suggested a number of tips to reduce exposure to light, such as using lamps with soft light instead of bright, overhead lights. Another major contributor to nighttime light are devices like TVs, cellphones, and computer screens.   

"Turn off all electronic devices at least one hour before bed as they emit blue wave spectrum light, which is the most problematic for sleep," she said. "If you cannot stop using your devices, turn the brightness down to the lowest setting and use blue light-blocking glasses."

Other tips include:

• Use blackout curtains to reduce outside light.
• For those who need light to get around at night, consider low-level amber or red lights, or inexpensive LED lights with motion detection that automatically turn back off.
• Use a dimmer that automatically lowers brightness to help transition to bedtime.
• If you're tempted by electronic devices, put them in another room before bed.
• Use an analog alarm clock or put your smartphone on airplane made while you sleep.

Along with increased risk for type 2, irregular sleep has been linked to other chronic conditions, like obesity, depression, and heart disorders. By simply reducing night-time light and getting better sleep, these risks are reduced while providing a range of benefits, such as improved memory, healing and metabolism. 

https://diatribe.org/diabetes-research/nighttime-light-exposure-increases-type-2-diabetes-risk