Summary
A bioRxiv preprint reports that people in windowless offices exposed to desk lamps supplemented with 850-nm near-infrared light had reduced glucose measurements over a three-day experiment, while standard LED exposure was associated with increased levels. The study used an oral glucose tolerance test and continuous glucose monitoring.
Researchers at University College London report that adding 850-nanometre (nm) near-infrared light to office lamps was associated with lower glucose measurements in a short human lighting experiment. The findings come from a bioRxiv preprint in which participants spent two hours each morning for three days under one of two lighting conditions in windowless offices.
A three-day office lighting experiment
One condition used standard LED desk lamps. The other used lamps supplemented with 850-nm light, a wavelength outside the visible range. The researchers then assessed glucose using two methods: an oral glucose tolerance test and continuous glucose monitoring.
An oral glucose tolerance test measures how the body responds to a standardised glucose load. Continuous glucose monitoring records glucose repeatedly over time, providing a picture of changes during everyday conditions rather than at a single test point.
The abstract reports significantly increased blood sugars among subjects exposed to standard LEDs and significantly reduced blood sugars among those exposed to lamps supplemented with 850-nm light. It describes these as real-world data collected in working interior environments, rather than a laboratory test of isolated cells or an animal experiment.
The supplied abstract does not report the number of participants, the numerical size of the glucose changes or confidence intervals. The exposure was also limited to two hours each morning over three days, so the reported result concerns a short-term lighting response.
Why the wavelength could affect metabolism
The authors’ explanation centres on mitochondria, the structures inside cells that help convert nutrients into adenosine triphosphate, or ATP, the molecule used to power cellular processes. The paper describes wavelengths between 670 and 900 nm as supporting mitochondrial function, while light in the 420–450-nm Soret band is described as undermining it.
Standard LED illumination is characterised in the preprint as covering roughly 400–650 nm. By adding 850 nm, the experimental lamps introduced a longer wavelength within the range the authors associate with stronger mitochondrial performance.
The proposed chain is that better mitochondrial activity increases the cells’ demand for glucose as a fuel for ATP production, which could reduce glucose circulating in the blood. In this experiment, the glucose measurements provide the observed outcome; the mitochondrial pathway is the biological explanation proposed by the researchers.
The study therefore brings the spectrum of indoor lighting into discussions about metabolism, alongside more familiar factors such as diet, physical activity and sleep. Its evidence is an early preprint result, and fuller study details and follow-up research would be needed to determine how consistently the effect occurs across different people, lighting environments and exposure periods.