Season 1 – Episode 5: Shedding light on… pupil size across the lifespan

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 learn about the witching hour, twilight, the forbidden zone, sundowning and much more! This episode is supported by the Daylight Academy. Links and resources related to the episode’s content:Daylight Academy: https://daylight.academy/ Daylight Awareness Week 2024: https://daylight.academy/daylight-awareness-week-2024/ Timestamps(00:00) Intro (02:28) Circadian forbidden zone (06:33) Sleep deprivation symptoms (08:15) Sleep deprivation as therapy (11:30) Twilight (14:30) Dusk without electric light (16:13) Sundowning (17:03) Darkness (23:10) Lack of daylight in the North (27:23) The witching hour (29:07) Light therapy (33:22) Dark therapy (38:28) Outro ContactFor feedback and questions, you can contact us at: [email protected] Follow us on social media to stay up to date with our episodes and discover related content: Twitter/X: https://x.com/lightoclock Instagram: https://www.instagram.com/lightoclockpodcast/ Website: https://www.tscnlab.org/podcast

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 get the answers to these and many other questions about light, circadian rhythms and mental health. Links and resources related to the episode’s content:The HELIOS-BD study: https://www.heliosbd.com/ The AMBIENT-BD study: https://www.ambientbd.com/ Timestamps(00:00) Intro (01:25) Introducing Prof. Smith (02:45) Circadian rhythms and mental health (05:20) In which direction is the relationship? (07:25) The role of light (13:28) What is bipolar disorder? (16:45) Current treatment options (17:54) Bipolar disorder and light sensitivity (20:10) The HELIOS-BD study (29:08) Patient recruitment (30:58) The AMBIENT-BD study (33:40) Co-production of research studies (38:47) Outro ContactFor feedback and questions, you can contact us at: [email protected] Follow us on social media to stay up to date with our episodes and discover related content: Twitter/X: https://x.com/lightoclock Instagram: https://www.instagram.com/lightoclockpodcast/ Website: https://www.tscnlab.org/podcast

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) Introducing Dr. Kervezee (01:46) The different body clocks (03:20) How do these clocks sync? (05:00) The orchestra and the conductor (06:31) Clocks out of sync (09:18) Desynchrony in real life (10:25) Social jetlag (11:18) Health consequences (14:40) Future research: how to mitigate impact (17:30) What can you do as a shift worker? (22:25) Outro ContactFor feedback and questions, you can contact us at: [email protected] Follow us on social media to stay up to date with our episodes and discover related content: Twitter/X: https://x.com/lightoclock Instagram: https://www.instagram.com/lightoclockpodcast/ Website: https://www.tscnlab.org/podcast

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 questions about chronotype. Links and resources related to the episode’s contentMorningness-Eveningness Questionnaire (MEQ) [https://qxmd.com/calculate/calculator_829/morningness-eveningness-questionnaire-meq] The Munich ChronoType Questionnaire (MCTQ) [https://www.thewep.org/documentations/mctq] Timestamps(00:00) Intro (01:17) Introducing Dr. Biller (02:29) What is chronotype? (07:26) Biological measures of chronotype (09:34) Factors that affect chronotype (10:36) Can your chronotype change? (12:57) The biological vs the social clock (16:01) Can night owls become early birds? (18:18) School start times (20:52) Sex differences (22:38) How to know your chronotype? (29:13) Summary (30:56) Outro ContactFor feedback and questions, you can contact us at: [email protected] Follow us on social media to stay up to date with our episodes and discover related content: Twitter/X: https://x.com/lightoclock Instagram: https://www.instagram.com/lightoclockpodcast/ Website: https://www.tscnlab.org/podcast

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 on sleep and circadian rhythms. Links and resources related to the episode’s contentGraphic of sleep pressure (process S) and circadian rhythms (process C) [https://static.physoc.org/app/uploads/2019/03/22194528/Fig3.jpg] Further reading on the two-process model of sleep [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9540767/] Disconnect between how sleepy people feel (subjective) and how sleepy they actually are (objective) [https://doi.org/10.2147/NSS.S312808] Timestamps(00:00) Intro (02:08) Introducing Dr. Lok (02:44) Circadian rhythms: from morning to night (06:37) Sleep and circadian rhythms: same or different? (08:10) The two-process model of sleep (09:08) The “forbidden” zone (10:02) Travel and jet-lag (11:35) How does sleep pressure work? (14:28) Can you catch-up on lost sleep? (17:19) How to know if you’re sleep-deprived? (20:03) Separating process S and C in the lab (26:20) Outro ContactFor feedback and questions, you can contact us at: [email protected] Follow us on social media to stay up to date with our episodes and discover related content: Twitter/X: https://x.com/lightoclock Instagram: https://www.instagram.com/lightoclockpodcast/ Website: https://www.tscnlab.org/podcast

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 contentPhotos of Jürgen Aschoff’s 1960’s bunker experiment [https://www.spiegel.de/geschichte/chronobiologie-schlaflabor-im-bunker-a-951188.html] Original publication on the discovery of the period gene by Ronald Konopka and Seymour Benzer [https://www.pnas.org/doi/full/10.1073/pnas.68.9.2112] Further reading on the history of Chronobiology and the discovery of the molecular mechanisms of circadian rhythms [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6138759/] Timestamps(00:00) Intro (01:10) Introducing Prof. Shafer (02:14) Beginnings in plants (05:18) Other organisms (06:10) Studies in humans: caves and bunkers (09:53) Where is the circadian clock? (11:24) Search for the clock genes (13:22) Why are fruit flies so important? (14:50) Discovery of the period gene (17:38) The fly vs. the human clock (20:19) Flies and modern life (22:49) Outro ContactFor feedback and questions, you can contact us at: [email protected] Follow us on social media to stay up to date with our episodes and discover related content: Twitter/X: https://x.com/lightoclock Instagram: https://www.instagram.com/lightoclockpodcast/ Website: https://www.tscnlab.org/podcast

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 media to stay up to date with our episodes and discover related content: Twitter/X: https://x.com/lightoclock Instagram: https://www.instagram.com/lightoclockpodcast/ Website: https://www.tscnlab.org/podcast

[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 Technical University of Munich. Links and resources related to the episode’s content: UNESCO International Day Of Light Recommendations for light exposure (Brown et al., 2022) How to activate the daylight exposure function on the Apple watch and iPhone Questionnaire to determine chronotype: Munich Chronotype Questionnaire (Roenneberg et al., 2003) For feedback and questions, you can contact us at [email protected]. Follow us on social media to stay up to date with our episodes and discover related content, and check out our website: Twitter: https://twitter.com/lightoclock Instagram: https://www.instagram.com/lightoclockpodcast/ Website: https://www.tscnlab.org/podcast

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 current metrics for measuring light may not reflect our non-visual perception of light. Tune in to explore the relationship between light and the human pupil. Contact us: [email protected] Website: https://tscnlab.org/podcast

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. Join us for this enlightening conversation with Dr. Elise McGlashan on Light O'Clock as we uncover the science behind the interplay of light and sleep. Contact us: [email protected] Website: https://tscnlab.org/podcast