How daylight helps body control blood sugar

We spend almost 90% of our time indoors, yet natural light is the “main clock” that synchronizes our biological rhythms, writes salute.eu.

When this signal weakens, the risk is a kind of misalignment: the brain and peripheral organs, including muscles, struggle to stay active, CE Report quotes ATA.

This is the focus of a study published in Cell Metabolism: 13 people with type 2 diabetes, all over the age of 65, were observed under a highly controlled protocol, with two conditions compared in random order and at least four weeks apart.

In one session, they worked from 8:00 a.m. to 5:00 p.m. in a room with large windows and natural light; in the other, they followed the same routine but under continuous artificial light. Meals, physical activity, sleep, and even screen time were kept as identical as possible.

The results, despite the small sample size and a duration of only four and a half days, were consistent: with natural light, participants spent more time “within the desired blood sugar range”—about 59% of the time compared with 51% under artificial light—with less variability.

At the same time, metabolism shifted toward greater fat oxidation, a sign of improved metabolic flexibility, and melatonin levels were slightly higher in the evening, as if the entire day had been more carefully scheduled.