Light O'Clock

In the first episode of Season 4, we start with the foundations of circadian medicine. Together with our guest Henrik Oster, we take a tour through the circadian system and ask what biological timing has to do with health and disease. We discuss how the body coordinates different physiological and behavioural functions across the 24-hour day, what can happen when internal rhythms become disrupted,...

Light O'Clock is back with Season 4! In this new season, we explore how biological timing shapes health and disease, and how accounting for circadian rhythms may help improve prevention, diagnosis, and treatment. We will discuss topics such as immunity and vaccination, cancer care, neonatal health, metabolism, exercise, and shift work. Join us as we take a tour through the emerging field of circad...

In the final episode of this mini-series, Caro, Anna, and Priji explore how the built environment shapes our interactions with daylight. From balconies and windows to schools, workplaces, and public spaces, the places we move through every day influence how much natural light we receive and how we experience it. These spaces are more than design choices. They are shaped by culture, climate, geogra...

In the second episode of our Interacting with Daylight mini-series, Caro is joined by Anna and Priji again to explore how cultural traditions and individual behaviours shape our interactions with daylight. Building on the previous discussion of location, this episode shifts the focus to how social norms, gender roles, and cultural traditions shape people’s experiences and interactions with dayligh...

In this first episode of our new Interacting with Daylight mini-series, your host Caro is joined by Anna and Priji to discuss the Daylight Interaction Project, funded by the Daylight Academy. The project explores how people interact with daylight in everyday life and how this is shaped by factors such as location, built environments, culture and behaviours. The episode focuses on the first part of...

In this special episode of Light O’Clock, we share snippets from our very first live recording, captured on stage at Buch Wien in Vienna in November 2025. Host Caro Guidolin and her colleague Marie-Luise Schreiter answer audience questions on chronotype, light exposure, sleep, shift work, and why people feel more tired in winter.

Many people notice changes in mood, energy, and motivation during the dark winter months. In this episode, we explore Seasonal Affective Disorder (SAD) and the broader experience of feeling low in winter and, importantly, what science-backed strategies can help. We speak to Delainey Wescott about changes in sleep and circadian rhythms in SAD, and chat with Hester Parr and Hayden Lorimer about the...

Light O’Clock is going live from Vienna at Buch Wien 2025 on Saturday, 15 November – and this time, you set the agenda for the episode! Together with Marie Luise Schreiter, we’ll be diving into your questions about how light shapes our brains, bodies, health, and daily rhythms – live on stage. What have you always wanted to know about light, sleep, or circadian rhythms? Send us your question throu...

For our Season 3 finale of Light O’Clock, we dive into a timely and often overlooked issue: light pollution. Artificial light at night has become a constant in modern life — but what are the hidden consequences? Our guests, Barbara Harding , Travis Longcore and Karolina M. Zielińska-Dąbkowska , bring scientific insight into how nighttime light exposure may affect human health, including possible l...

Why do early mornings feel so brutal for teens? In this episode, we explore the science behind teenage sleep and circadian rhythms and why early school start times may be setting students up for failure. We talk to students from Italy and Germany, and sleep researcher Dr. Anna Magdalena Biller , to understand how biology, not laziness, is behind teen sleep struggles — and what schools, parents, an...

Today, more and more children around the world are developing myopia, or nearsightedness — especially in East Asia, where prevalence among school-aged children can reach up to 70%. Can simply spending more time outside in daylight help protect children from developing myopia? In this episode, our guest Asst. Prof. Raymond P. Najjar (National University of Singapore) breaks down: What we know about...

How does life in cities versus rural areas shape our circadian rhythms? How does access to electricity — or the lack of it — impact sleep timing? And what happens to our circadian rhythms when we move from an urban setting to camping outside? Our guest Luísa Klaus Pilz (Charité - Universitätsmedizin Berlin) comments on field studies carried out when she was a PhD student and postdoc...

On 30 March 2025, Europe will switch to Daylight Saving Time (DST), moving clocks forward by one hour. While many people enjoy longer evenings, scientists in sleep and circadian research argue that DST can be harmful to our health. In this episode, we dive into the controversy surrounding DST and answer three key questions: Why do chronobiologists want to get rid of DST? What does the evidence say...

Light O’Clock is back with a brand new season! In the next five episodes, we’re looking beyond the biology of body clocks to explore how our modern world shapes our biological rhythms — and how politics and society influence decisions about our body clocks. We’ll cover the controversies around clock changes and school start times, discuss how indoor lifestyles might be affecting our vision, compar...

How do individuals with lived experience and researchers come together to co-design a scientific study? In this special episode of Light O’Clock, we hear from Patrica Pelosi and Nomhle Nhlapho, who have lived experience of bipolar disorder and have contributed to shaping the HELIOS-BD study (more in our previous episode). We also hear from Dr Amy Ferguson, who works closely with the Lived Experien...

On the occasion of Daylight Awareness Week 2024 (28-31 October) and Halloween, Light O’Clock is partnering up with the Daylight Academy to bring you an extra special episode that blends the science, the spooky, and the supernatural! Our host dives into the eerie mysteries of circadian rhythms, sleep and daylight with Prof. em. Anna Wirz-Justice, a pioneer in the field of chronobiology. Tune in to...

In today’s episode, we dive deep into the relationship between light, circadian rhythms and mental health with Prof. Daniel Smith from the University of Edinburgh. What role do light sensitivity and circadian rhythms play in bipolar disorder? How can we design studies to answer key questions in this area, and how can the involvement of patients ensure the success of a research study? Tune in to ge...

Did you know that your body has many body clocks? Like instruments in an orchestra, they each have a specific role to play, but how do they stay in rhythm with each other? In today’s episode, Dr. Laura Kervezee dives deep into the different body clocks, who is the conductor that makes our body run in harmony, and what happens when the rhythm goes out of sync. Timestamps (00:00) Intro (01:18) Intro...

Are you an early bird or a night owl? Can you choose to be an early type? In this episode, Dr. Anna M. Biller from the Technical University of Munich explains what chronotype is, how it changes throughout the lifespan, what happens when your biological clock and your social clock are out of sync, and how can you measure your type. Listen to uncover the answers to these and many other fascinating q...

In today’s episode, we dive deep into the relationship between circadian rhythms and the sleep-wake cycle with Dr. Renske Lok from Stanford University. Are they different or the same? What other processes in the body regulate your sleep? Can you catch-up on lost sleep? How can you even know if you are sleep-deprived and need more sleep? Tune in to get the answers to these and many other questions...

In this episode Prof. Orie Schafer, based at the CUNY Advanced Research Center, takes us through the history of the field of chronobiology, from its beginnings in plants, through studies in bunkers with humans, and the discovery of the clock genes thanks to the tiny but mighty fruit fly. Links and resources related to the episode’s content Photos of Jürgen Aschoff’s 1960’s bunker experiment [ http...

Light O'Clock is back with a brand-new season starting next week! In this season, we will dive deep into the relationship between circadian rhythms and health (mental and physical), shedding light on what happens when we "break" the rhythms, when we do not live according to our chronotype and much, much more! Stay tuned for new episodes starting next Tuesday, 3 September 2024. Follow us on social...

[This episode is available as a video episode on YouTube.] In occasion of International Day of Light (16 May 2024), the Light O’Clock team is bringing you an extra special episode: We answer your burning questions on the topic of light and circadian rhythms! Our host unpacks listeners’ questions with guest Prof. Dr. Manuel Spitschan from the Max Planck Institute for Biological Cybernetics and the...

In this episode of Light O’Clock, Caro Guidolin chats with Rafael Lazar, a PhD student in the field of chronobiology at the University of Basel. Rafael studies the real-world effects of light on the pupil. He elaborates on the impact of light on the pupil as he talks us through his remarkable study of pupil measurement under authentic, real-world conditions. Additionally, our guest highlights why...

Have you ever wondered why most people lean towards dark bedrooms for a good night's sleep? How light at night can affect our sleep is the focus of this episode of Light O’Clock. Dr. Elise McGlashan, an expert from the Melbourne School of Psychological Sciences, joins us to discuss how our bodies use light to regulate melatonin production, the nighttime hormone crucial to our sleep-wake cycle. Joi...