The science of light: how it shapes our health and the world around us

Have you ever thought about how light influences our daily lives? From the natural rhythms of day and night to the glow of artificial lights, it’s clear that light plays a huge role in shaping our world. Across centuries, humans have celebrated the connection between light, cycles and life in their cultures and traditions. But it’s not just a poetic idea — science shows us that light and its cycles have profound effects on our health and well-being.

In fact, Dr. Thomas Milner, a leading expert in biophotonics and professor of surgery in the Division of Surgical Oncology at Baylor College of Medicine, is researching how light interacts with biological timekeeping. His work explores how light exposure influences cellular processes and could unlock new ways to reduce the negative effects of artificial light on health.

Light’s impact on health

Scientists have studied cycles in nature for a long time. From the movement of stars to ocean tides, repeating patterns help us understand things like light, sound and even tiny particles like atoms and molecules.

“In the 20th century, researchers found that tiny energy-based vibrations help explain the structure of atoms, molecules and even nuclear systems. Interestingly, these same concepts connect to our body’s internal clock and how artificial light – especially blue light at night – can throw it off,” Milner said.
Artificial light at night (ALAN) can have unexpected effects on our bodies. Research has shown ALAN raises blood sugar levels and alters body weight – but only in males. Other scientists have studied how the one-hour shift of daylight saving time affects our internal clocks. Their findings suggest that the impact varies based on whether you’re a morning or night person and how much light you’re exposed to each day.

The cells in our eyes have a profound influence on our internal clocks. Researchers studied retinal Müller glial cells (specialized cells in the eye) and how they might contribute to circadian disruptions. Their work links these disruptions to conditions like Alzheimer’s disease-related retinopathy, showing just how deeply light impacts our health.

Humans evolved over thousands of years in sync with the natural day-night cycle, but after the invention of the electric light bulb in 1880 and since, ALAN has drastically changed that. Night shifts, late-night screen time and urban living have exposed us to more artificial light than ever before, leading to significant health concerns.

The effects of ALAN go beyond sleep disruption. It has been linked to higher risks of breast cancer, particularly in women who work night shifts or live in brightly lit urban areas. Shortened sleep duration – less than seven hours a night – is now widespread and contributes to issues like high blood pressure, obesity, type-2 diabetes and cardiovascular disease. For children, the effects can be even more pronounced, as they need more sleep for optimal growth and development.

Light-based research at Baylor

Researchers like Milner are making exciting discoveries about how light influences our health and biological rhythms. At Baylor, Milner leads efforts to translate nano-biophotonic technologies into real-world applications, particularly in cancer diagnostics and therapy.

“There’s so much potential to explore how circadian rhythms impact biology and apply that knowledge to healthcare innovation,” Milner said. “For example, we know the time of day affects blood pressure readings. Instead of relying on a single measurement at the doctor’s office, we need unobtrusive sensors that seamlessly fit into our daily lives and provide more accurate, continuous data.”

By Tiffany Harston, senior communications associate in the Michael E. DeBakey Department of Surgery