Artificial light at night does far more than disrupt sleepit can throw off immune defenses, fuel inflammation, alter metabolism, and affect mood regulation.
Studies show that the glow from devices, streetlights, and other nighttime sources confuses the bodys natural rhythms, which evolved to sync with the suns light and darkness.
From Farm Work to Neuroscience Leadership
A recent Genomic Press Innovators & Ideas feature in Brain Medicine profiles the groundbreaking work of neuroscientist Dr. Randy J. Nelson, focusing on his research into the far-reaching effects of disrupted circadian rhythms on both brain performance and overall health. The piece also follows his unusual career path, beginning with early jobs in farming and as an autopsy assistant, and leading to his position as one of the most recognized experts on biological timing systems.
As the current chair of the Department of Neuroscience at West Virginia University, he has devoted the past ten years to uncovering the lesser-known risks posed by exposure to artificial light at night. His studies reveal that nighttime light does much more than reduce sleep quality; it can impair immune responses, spark neuroinflammation, interfere with metabolic processes, and alter mood regulation.
From Turkey Processing Plant to Top Research Institution
The profile highlights his remarkable rise in academia. During high school, he worked night shifts in a turkey processing facility, followed by roles conducting autopsies in two Cleveland hospitals. A chance employment opening at the San Diego Zoo eventually brought him to the University of California, San Diego, setting the stage for his academic ascent.
My path to academia is typical in the sense that it is not typical,' Dr. Nelson reflects in the interview. His unique background, including becoming the first person in the United States to simultaneously earn two separate PhDs (in Psychology and Endocrinology from UC Berkeley), shaped his integrative approach to neuroscience research.
Randy J. Nelson, PhD, West Virginia University, USA. Credit: Randy J. Nelson, PhD
Circadian Disruption: A Modern Health Crisis
Dr. Nelsons laboratory has published groundbreaking findings on how exposure to artificial light at night affects multiple body systems. The research goes beyond simple sleep disturbance to reveal profound effects on physiological processes that evolved over millions of years to function in sync with natural light-dark cycles.
Key areas of impact identified by Dr. Nelsons research include immune system dysfunction, where light exposure at inappropriate times can suppress typical immune responses or trigger excessive inflammation. The work also demonstrates clear links between circadian disruption and metabolic disorders, potentially contributing to the obesity epidemic. Perhaps most concerningly, 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 can the body recover from chronic light exposure? What is the contribution of time-of-day as a biological variable? These questions drive ongoing investigations in Dr. Nelsons laboratory.
Translating Discovery to Clinical Practice
Moving beyond foundational research, Dr. Nelsons team currently conducts clinical trials examining whether blocking disruptive light effects can improve outcomes for intensive care patients. Two major trials focus on stroke recovery and cardiac surgery patients, populations particularly vulnerable to the harsh lighting conditions typical of hospital ICUs.
Circadian rhythms are a fundamental aspect of biology, and much is known from foundational science about them, Dr. Nelson explains. However, little of this foundational science has been translated to clinical medicine.
The research also extends to healthcare workers themselves. A third clinical trial investigates whether bright blue light visors can help night shift nurses reset their circadian rhythms, potentially improving their sleep quality, cognitive performance, and mood. Could similar interventions help other shift workers across various industries maintain better health despite irregular schedules?
Time as a Biological Variable
One of Dr. Nelsons most provocative proposals involves recognizing time-of-day as a crucial biological variable in all research. He argues that experimental results can vary dramatically depending on when studies are conducted, yet this information rarely appears in scientific publications.
The answer to an experimental question may depend in part on the time-of-day when the question is asked, Dr. Nelson notes. This observation has profound implications for research reproducibility and could explain why some studies fail to replicate previous findings.
Building the Next Generation of Neuroscientists
Throughout his career at Johns Hopkins University, Ohio State University, and now West Virginia University, Dr. Nelson has mentored 25 PhD students and 16 postdoctoral researchers. His leadership philosophy emphasizes creating supportive environments where young scientists can thrive. His mentoring philosophy has been featured in a recent Society for Neuroscience Neuronline podcast.
As current president of the Association of Medical School Neuroscience Department Chairs, Dr. Nelson advocates for resources and policies that support early-career researchers. He particularly values helping faculty members navigate the challenging early stages of their careers through strategic resource allocation and mentorship.
What role might circadian rhythm research play in addressing the mental health crisis among graduate students and postdocs? How can academic institutions better support work-life integration for researchers studying around-the-clock biological processes?
A Vision for Healthier Living
Dr. Nelsons research carries immediate practical implications for public health. Simple interventions like reducing evening screen time, using warmer light colors after sunset, and maintaining consistent sleep schedules could significantly impact population health. His work suggests that respecting our evolutionary heritage by aligning modern life more closely with natural light patterns could prevent numerous chronic health conditions. He recently published a trade book with Oxford University Press entitled, Dark Matters, to help the general public appreciate the importance of good circadian hygiene for health and wellness.
The interview also touches on Dr. Nelsons personal interests, including travel, biking, and gardening, activities that keep him connected to natural rhythms. His favorite place remains Southern California, where his academic journey began through that serendipitous opportunity at the San Diego Zoo decades ago. Dr. Randy J. Nelsons Genomic Press interview is part of a larger series called Innovators & Ideas that highlights the people behind todays most influential scientific breakthroughs. Each interview in the series offers a blend of cutting-edge research and personal reflections, providing readers with a comprehensive view of the scientists shaping the future. By combining a focus on professional achievements with personal insights, this interview style invites a richer narrative that both engages and educates readers. This format provides an ideal starting point for profiles that explore the scientists impact on the field, while also touching on broader human themes.
Reference: Randy J. Nelson: Disruption of circadian rhythms on brain function and health by Randy J. Nelson, 8 July 2025, Brain Medicine.
DOI: 10.61373/bm025k.0083
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