Not sleeping in the dark increases the risk of diabetes

The link between the absence of darkness and an increased risk of type 2 diabetes was already proven two years ago. This time, this threat is confirmed in the “Lancet Europe”. Details from Géraldine Zamansky.

If you have until now been too lazy to close your shutters every evening, this column will perhaps re-motivate you. Because not sleeping in the dark would increase the risk of diabetes, explains Géraldine Zamansky, journalist at France 5 Health Magazine,

franceinfo: A new study confirms the importance of spending the night away from light?

Geraldine Zamansky: Exactly, to avoid increasing your risk of diabetes, you have to sleep in the dark. That is to say at most with the equivalent of lighting a candle. This is what is shown by monitoring over 8 years of 85,000 British people who wore a light sensor for a week, day and night, at the start of this study.

The simple fact of falling asleep while leaving the TV or a bedside lamp on would create an increased risk of diabetes of 29%! This percentage rises to 39% with a ceiling light of medium intensity. And 53% in case of sufficiently powerful neon. This is what Andrew Phillips, first author of this publication, deciphered for me (in the Lancet Europe), and specialized in the study of sleep, at the Australian University of Flinders.

And this confirms another research that you spoke to us about, which already reflected the imperfect protection of the eyelids against light?

Yes, light passes through our closed eyelids, and would send a sort of alert signal to the brain. So instead of mainly storing, our “conductor” leaves, for example, enough sugar in the blood, in case the muscles need to activate. It is a disruption of the balance normally ensured by insulin. Like at the start of diabetes.

And you remember correctly, we had already mentioned research which found abnormal sugar levels in the blood of volunteers, after a night in a lit room. This time, the monitoring of thousands of people over 8 years showed a risk of diabetes which impressed Andrew Philips’ team. He also told me that the other factors favoring this disease had been “neutralized”, to isolate the effect of night light.

This study shows the importance of respecting our “biological clock”?

Yes, you are right to recall that it is the fundamental rhythm of the organism that we are talking about. Andrew Philips emphasizes the importance of maintaining regularity in the alternation between active phases, during the day, and resting phases, at night.

And he still wanted to share some good news, especially for those who work night shifts: truly putting yourself in the dark can send an effective “rest” signal to the brain, even in the middle of the day. By allowing yourself enough hours of sleep…

The study