They explain how artificial light at night damages brain health

Nighttime light causes a change in our brains that can have long-term consequences. An article published in Brain Medicine highlights that the disruption of circadian rhythms caused by nighttime light affects brain function and overall health.

Nighttime light not only affects sleep quality , but also profoundly alters immune function, triggers neuroinflammation, disrupts metabolism, and influences mood regulation, explains Randy Nelson, chair of the Department of Neuroscience at West Virginia University .

The research goes beyond simple sleep disruption and reveals profound effects on physiological processes that have evolved over millions of years to function in sync with natural light and dark cycles.

Key areas of impact identified include immune system dysfunction, where exposure to light at inappropriate times can suppress typical immune responses or trigger excessive inflammation. The work also demonstrates clear links between circadian disruption and metabolic disorders, which could contribute to the obesity epidemic. Perhaps most concerning, the research shows direct effects on mood regulation, with implications for understanding depression and anxiety disorders.

What specific wavelengths of light are most disruptive to circadian rhythms? How quickly does the body recover from chronic light exposure ? What is the contribution of time of day as a biological variable?

Nelson's team is currently conducting clinical trials examining whether blocking the effects of disruptive light can improve outcomes for intensive care patients. Two major trials focus on recovering stroke and heart surgery patients, populations particularly vulnerable to the harsh lighting conditions typical of hospital ICUs.

The research has immediate practical implications for public health. Simple interventions such as reducing screen time in the evening, using warmer light colors at dusk, and maintaining regular sleep schedules could have a significant impact on population health. Their work suggests that respecting our evolutionary heritage, aligning modern life with natural light patterns, could prevent numerous chronic diseases.