“Harmless” nighttime habit boosts diabetes risk?

Just yesterday, I shared with you the importance of getting a good night’s sleep…

And how ongoing sleep disruptions may point to an Alzheimer’s diagnosis down the road.

Now, I have more shocking news to reveal. This time, about your sleeping environment.

In fact, this “harmless” nighttime habit may increase your diabetes risk.

Let me explain…

Keeping the lights on ruins more than just your sleep

According to a recent study, sleeping with the lights on may not only ruin your sleep, but also your blood sugar.

Researchers from Northwestern University looked at the effect of different light exposure levels while sleeping on sleep quality and blood glucose levels.

For the study, 20 young adults were randomized to one of two sleeping conditions:

  • Sleeping with a dim light (like a small nightlight) for one night, followed by moderate ambient light (like an overhead room light) for one night.
  • Sleeping with a dim light both nights.

Participants underwent overnight polysomnography to assess sleep quality and provided blood samples before and after food intake to assess glucose levels.

Ultimately, the researchers found that exposure to moderate ambient light can impair insulin levels and negatively affect how your body reacts to glucose.

In fact, researchers found a higher amount of insulin was needed to normalize glucose levels the next morning, compared to those who only slept with a dim light.

(As I’ve shared with you before, insulin resistance is the first sign of diabetes.)

What’s more, those who slept with moderate ambient light experienced less quality sleep.

They spent more time in deeper sleep stages (called N2 sleep), but less time in slow-wave (important for memory) and rapid eye movement (REM) sleep (the dreaming phase).

Turn down the lights

This isn’t the first study to investigate the effect of light on sleep and metabolism.

In one study, artificial light at nighttime (like from a television) was associated with a higher risk of obesity in women. And yet another study revealed a link between artificial light and type 2 diabetes in an elderly population.

Now, don’t get me wrong… I’m not suggesting you stumble around in the dark at night.

If you need a light for safety reasons, just keep it as dim as possible. And make sure it’s red-amber light. (Avoid exposure to blue light, including your TV, tablet, and smartphone.)

I also suggest investing in room darkening shades or curtains. This will help keep the light from streetlamps and other environmental “light pollution” out of your bedroom while you sleep. (A sleep mask will do the trick, too.)

Until next time,

Dr. Fred

P.S. Not a sound sleeper? Check out my Perfect Sleep Protocol. This comprehensive, online learning tool provides drug-free solutions for a deeper, more refreshing sleep night after night. Click here now for more details!


“Sleeping with the light on may increase diabetes risk.” Medical News Today, 03/23/2022. (medicalnewstoday.com/articles/sleeping-with-the-light-on-may-increase-diabetes-risk)