Can leaving the light on during sleep increase the risk of diabetes?
There are many people who, even as adults, have the habit of sleeping with the light on. But this is not a healthy habit. In fact, it could increase your risk of developing type 2 diabetes, according to a new study from Flinders University in Australia.
What does the study say?
The researchers who carried out the study, led by Dr Andrew Phillips and published in The Lancet, realised that the changes in circadian rhythms caused by exposure to light at night, although small, could be extremely harmful to health.
In particular, they would increase the likelihood of developing type 2 diabetes, a theory already supported by a 2023 study which found that sleeping with the light on at night would also promote the development of hypertension and obesity, especially in the elderly.
To reach this conclusion, researchers followed volunteers who took part in the study for 9 years and eventually found that those who were most exposed to light between 00:30 and 6 a.m. had developed a higher risk of developing type 2 diabetes, regardless of their exposure to light during the day.
Why can sleep with the light on be a cause of diabetes?
Keeping the light on while you sleep alters your circadian rhythm, which is the body’s internal biological clock that regulates the light-dark cycle. When it is dark, the body is stimulated to rest, and when it is light, it is stimulated to remain active.
Disruption of this rhythm can lead to reduced glucose tolerance and abnormal insulin production. In addition, exposure to light during sleep can cause metabolic dysfunction, which in turn can lead to various more or less serious adverse events, ranging from simple fatigue, headaches and digestive problems to more serious diseases such as type 2 diabetes.
Similarly, people who work at night or frequently work night shifts and do not maintain a regular sleep-wake cycle are at greater risk of developing this condition.
Of course, there are many factors that lead to the onset of type 2 diabetes, but the results of the study suggest that sleeping with the light on at night may be one of them, and conversely, sleeping in the dark appears to be beneficial. Based on these findings, scientists are continuing their research to understand whether better lighting in certain environments can be linked to long-term health improvements.