Looking back: The 4th Dutch Chronobiology Symposium

On 27 March 2026, an international community of chronobiologists gathered at Leiden University’s Kamerlingh Onnes Building for the 4th Dutch Chronobiology Symposium. This full‑day meeting was dedicated to circadian biology it all of its many forms, attracting researchers from neurology and immunology to ecology and light design.

The symposium opened with a keynote lecture by Prof. Chris Colwell (UCLA), who explored how circadian disruption contributes to neurodevelopmental disorders, and how timing‑based interventions may aid treatment.

A second keynote was delivered by Prof. Russell G. Foster (University of Oxford), who highlighted the effects of light on circadian rhythms in both mice and humans. He offered a compelling overview of what science has uncovered so far, and what key questions remain, about light as a fundamental regulator of biological time.

Throughout the day, PhD candidates and postdoctoral researchers presented their latest findings through talks and posters. Their work reflected the broad and rapidly evolving landscape of chronobiology, ranging from fundamental research to clinical and environmental applications.

As tradition dictates, the symposium concluded with the presentation of the Antonia Kleinhoonte Award for Best Abstract Presentation. This year’s award – including a €250 prize intended to support academic development – was granted to Roos Bos (UMC Utrecht, LUMC) for her outstanding poster on implementing biologically meaningful light measurements in the neonatal intensive care unit.

Following the scientific program, participants walked to Leiden University’s Academy Building for the farewell lecture of Prof. Joke Meijer (LUMC), who is retiring. In her talk titled “With an eye on the time,” she reflected on her remarkable career and the evolution of chronobiology as she witnessed and shaped it. The event concluded with several honorary speeches and a very special moment: the Mayor of Leiden took the stage to present Prof. Meijer with a royal knighthood in the Order of the Lion of the Netherlands, recognizing her exceptional contributions to science and research.

This memorable ceremony marked the end of another successful edition of the Dutch Chronobiology Symposium. The event, organized by the BioClock Consortium, once again highlighted the strength, breadth, and growing impact of chronobiology research in the Netherlands.