CHRONO:MEDICINE

Dr. Jan-Frieder Harmsen

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MEDICINE
EVERY TWO WEEKS

CHRONO:MEDICINE

In the CHRONO:MEDICINE podcast (formerly known as 247Muscle), your host (Dr. Jan-Frieder Harmsen) interviews scientists, coaches and other practitioners in the field of chronobiology, circadian rhythm, skeletal muscle physiology, exercise performance and sleep. The podcast aims to provide translational knowledge from research findings for students, researchers and the generally interested public.

28 OCT

E25 - Part 2: Improving health & sleep through daylight with Christian Cajochen

In the second part with Prof. Christian Cajochen (Head of the Centre for Chronobiology at the University of Basel in Switzerland), contributing to the Daylight Awareness Week (28th of October - 2nd of November 2024), we continue our discussion around the impact of daylight on our health, with a special focus on sleep. Christian summarizes the negative effects of bright electric light exposure on sleep and other health outcomes. On the other hand, he highlights the importance of daylight and alternatively increased electric light intensities during daytime for sleep. We also discuss how seasonal changes in daylight affect us more than we think. Christian gives insights into a real-world example of how switching to dynamic lighting at the workplace changed people’s wellbeing. And lastly, we discuss if a medical pill could eventually replace the health effects of daylight. More information about the Daylight Awareness Week: ⁠https://daylight.academy/daylight-awareness-week-2024/⁠ Chapters: (0:00:12) Intro & Daylight Awareness Week (0:00:48) Topics of this episode series (0:02:13) Introduction to sleep (0:04:15) Evening electric light & sleep (0:09:42) Daylight & sleep (0:15:47) Seasonal effects of daylight (0:20:33) Can higher light intensities during daytime reduce negative effects of evening light? (0:25:47) How to tackle the lack of daylight as a society? (0:36:00) Take-home message on daylight & health (0:37:39) Christian’s career goals & future research (0:41:15) Funny anecdotes (0:47:18) Outro & Teaser to Part 2 Studies that Christian refers to: Evening administration of melatonin and bright light: Interactions on the EEG during sleep and wakefulness https://doi.org/10.1046/j.1365-2869.1998.00106.x Blue Blocker Glasses as a Countermeasure for Alerting Effects of Evening Light-Emitting Diode Screen Exposure in Male Teenagers https://doi.org/10.1016/j.jadohealth.2014.08.002 Evaluating the Association between Artificial Light-at-Night Exposure and Breast and Prostate Cancer Risk in Spain (MCC-Spain Study) https://doi.org/10.1289/EHP1837 Camping Study: “Circadian Entrainment to the Natural Light-Dark Cycle across Seasons and the Weekend” 10.1016/j.cub.2016.12.041 Effect of daylight LED on visual comfort, melatonin, mood, waking performance and sleep https://doi.org/10.1177/1477153519828419 Positive Effect of Daylight Exposure on Nocturnal Urinary Melatonin Excretion in the Elderly: A Cross-Sectional Analysis of the HEIJO-KYO Study https://doi.org/10.1210/jc.2012-1873 Effect of Bright Light and Melatonin on Cognitive and Noncognitive Function in Elderly Residents of Group Care Facilities: A Randomized Controlled Trial https://doi.org/10.1001/jama.299.22.2642 Preprint article: “Sex and seasonal variations in melatonin suppression, and alerting response to light” https://doi.org/10.1101/2024.10.18.619012 Light therapy in non-seasonal depression: An update meta-analysis https://doi.org/10.1016/j.psychres.2020.113247 Pre-print article: “Afternoon to early evening bright light exposure reduces later melatonin production in adolescents” https://doi.org/10.1101/2024.10.02.616112 Regular Caffeine Intake Delays REM Sleep Promotion and Attenuates Sleep Quality in Healthy Men https://doi.org/10.1177/07487304211013995 Evidence that the Lunar Cycle Influences Human Sleep 10.1016/j.cub.2013.06.029 How to contact Christian Cajochen: Email: Christian.Cajochen@upk.ch Twitter: @ollen44 LinkeIn: https://www.linkedin.com/in/christian-cajochen-1435258/

48 min
28 OCT

E24 - Part 1: Improving health & sleep through daylight with Christian Cajochen

As part of the Daylight Awareness Week (28th of October - 2nd of November 2024), Prof. Christian Cajochen (Head of the Centre for Chronobiology at the University of Basel in Switzerland) talks about the impact of daylight on our health, with a special focus on sleep. In the first part, we talk about the importance of light for the circadian timing system within our bodies, with melatonin playing an important role. Christian explains why light can have very different effects on our health depending on the time of day of light exposure, and highlights the most important time to see daylight. Christian points out the benefits of daylight particularly for older people. We also critically discuss how difficult it is to study the health effects of daylight without any confounding from other "side-benefits" outdoors. And lastly, we discuss the effects of light on our cardiovascular system (like heart rate and blood pressure) as well as alertness. More information about the Daylight Awareness Week: https://daylight.academy/daylight-awareness-week-2024/ Chapters: (0:00:12) Intro & Daylight Awareness Week (0:02:10) Topics of this episode series (0:03:33) Introducing Christian Cajochen (0:08:21) Daylight vs. electric light (0:13:28) Circadian clocks & melatonin (0:20:31) Wavelength dependency (0:23:13) Timing of light matters (0:30:43) How to study health effects of daylight without confounders? (0:38:32) Light & Cardiovascular health (0:45:31) Warm feet to promote sleep (0:52:14) Light & Blood pressure (0:56:11) Outro & Teaser to Part 2 Studies that Christian refers to: The aging clock: circadian rhythms and later life https://doi.org/10.1172/JCI90328 A Phase Response Curve to Single Bright Light Pulses in Human Subjects https://doi.org/10.1113/jphysiol.2003.040477 Positive Effect of Daylight Exposure on Nocturnal Urinary Melatonin Excretion in the Elderly: A Cross-Sectional Analysis of the HEIJO-KYO Study https://doi.org/10.1210/jc.2012-1873 The biological clock tunes the organs of the body: timing by hormones and the autonomic nervous system https://doi.org/10.1677/joe.0.1770017 Light activates the adrenal gland: Timing of gene expression and glucocorticoid release 10.1016/j.cmet.2005.09.009 Warm feet promote the rapid onset of sleep https://www.nature.com/articles/43366 Functional link between distal vasodilation and sleep-onset latency? https://doi.org/10.1152/ajpregu.2000.278.3.R741 Changing color and intensity of LED lighting across the day impacts on circadian melatonin rhythms and sleep in healthy men https://doi.org/10.1111/jpi.12714 Circadian mechanisms of 24-hour blood pressure regulation and patterning https://doi.org/10.1016/j.smrv.2016.02.003 Alerting effects of light https://doi.org/10.1016/j.smrv.2007.07.009 How to contact Christian Cajochen: Email: Christian.Cajochen@upk.ch Twitter: @ollen44 LinkeIn: https://www.linkedin.com/in/christian-cajochen-1435258/

58 min
27 SEPT

E23 - Part 2: Timing of caloric restriction for longevity with Victoria Acosta-Rodriguez

After discussing in the first part how caloric restriction can extend lifespan, Dr. Victoria Acosta-Rodriguez (Leader of the Circadian Biology of Aging Unit at the National Institute on Aging (NIA), USA) talks in the second part about her recent study showing that eating these reduced calories always at a certain time of day extends the lifespan of mice even further. Beyond longevity, her study reveals that enhanced health benefits are achieved when feeding versus fasting times are aligned with the natural active and rest phase of mice as dictated by circadian clocks. In the end, we discuss the feasibility of long-term caloric restriction for humans and if similar health benefits could be expected in humans. Chapters: (00:00:45) Recap Part 1 (00:01:28) Part 2 topics (00:02:09) Interview start (00:03:28) Explaining the study design (00:10:01) What kind of food did mice eat and why? (00:13:56) Body weight changes over the lifespan (00:15:58) Relevance of fasting duration (00:19:45) A calorie is a calorie? (00:22:47) The longest-lived mice (00:25:49) Cause of death for 300 mice (00:29:46) Physical activity as a survival predictor (00:31:56) Body composition & metabolic health (00:35:55) 48-hour liver samples (00:47:18) Study limitations (00:51:59) Monkey studies (00:55:16) Feasibility of caloric restriction for humans (00:59:21) Personal perspective (01:09:00) Outro Main study that we will discuss in depth: Acosta-Rodriguez, V., Rijo-Ferreira, F., Izumo, M., Xu, P., Wight-Carter, M., Green, C.B., and Takahashi, J.S. (2022). Circadian alignment of early onset caloric restriction promotes longevity in male C57BL/6J mice. Science 376, 1192-1202. 10.1126/science.abk0297. Additional papers that Victoria refers to: Rhesus Monkeys - Caloric restriction & Lifespan Mattison, J. A. et al. Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study. Nature 489, 318–321 (2012). Colman, R. J. et al. Caloric restriction reduces age-related and all-cause mortality in rhesus monkeys. Nat. Commun. 5, 3557 (2014). Mattison, J. A. et al. Caloric restriction improves health and survival of rhesus monkeys. Nat. Commun. 8, 14063 (2017). Humans -TRF Sutton, E.F., Beyl, R., Early, K.S., Cefalu, W.T., Ravussin, E., and Peterson, C.M. (2018). Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Cell Metab 27, 1212-1221 e1213. 10.1016/j.cmet.2018.04.010. Humans - CALERIE study Martin, C. K. et al. Effect of calorie restriction on mood, quality of life, sleep, and sexual function in healthy nonobese adults: the CALERIE 2 randomized clinical trial. JAMA Intern. Med. 176, 743–752 (2016). Das, S. K. et al. Body-composition changes in the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE)-2 study: a 2-year randomized controlled trial of calorie restriction in nonobese humans. Am. J. Clin. Nutr. 105, 913–927 (2017). Mice – NIA Intervention Testing Program https://www.nia.nih.gov/research/dab/interventions-testing-program-itp Francesca Macchiarini, Richard A. Miller, Randy Strong, Nadia Rosenthal, David E. Harrison, Chapter 10 - NIA Interventions Testing Program: A collaborative approach for investigating interventions to promote healthy aging, In Handbooks of Aging, Handbook of the Biology of Aging (Ninth Edition), Academic Press, 2021, Pages 219-235, ISBN 9780128159620, https://doi.org/10.1016/B978-0-12-815962-0.00010-X Contact: Dr. Victoria Acosta-Rodriguez Email: victoria.acosta-rodriguez@nih.gov Twitter/X: @VickyAcostaR

1h 10m
20 AUG

E22 - Part 1: Timing of caloric restriction for longevity with Victoria Acosta-Rodriguez

Dr. Victoria Acosta-Rodriguez (Leader of the Circadian Biology of Aging Unit at the National Institute on Aging (NIA), USA) talks about her research on longevity and caloric restriction. In this first part, Victoria introduces us to longevity research: what kind of interventions and drugs are known to promote longevity and why precise terminology separating life- and healthspan is important. We discuss how the lifespan of mice relates to the lifespan of humans and to what degree we can therefore translate mice studies to the human setting. As we will learn, one intervention to promote longevity is caloric restriction, that is why Victoria also summarizes our current understanding of caloric restriction and defines its different forms. Chapters: (00:00:45) Podcast name and host updates (00:02:51) Introducing Victoria Acosta-Rodriguez (00:04:43) Interview start (00:05:26) Victoria’s personal background (00:09:04) Terminology: Lifespan vs. healthspan (00:12:25) What interventions promote longevity? (00:17:24) Defining caloric restriction (00:21:57) Relevance of feeding time for mice (00:30:12) Mice vs. humans for longevity studies (00:38:25) Changes in circadian rhythms upon aging? (00:44:26) Outro Main study that we will discuss in depth: Acosta-Rodriguez, V., Rijo-Ferreira, F., Izumo, M., Xu, P., Wight-Carter, M., Green, C.B., and Takahashi, J.S. (2022). Circadian alignment of early onset caloric restriction promotes longevity in male C57BL/6J mice. Science 376, 1192-1202. 10.1126/science.abk0297. Additional papers that Victoria refers to: Mice - time-restricted feeding, regular chow Damiola, F., Le Minh, N., Preitner, N., Kornmann, B., Fleury-Olela, F., and Schibler, U. (2000). Restricted feeding uncouples circadian oscillators in peripheral tissues from the central pacemaker in the suprachiasmatic nucleus. Genes Dev 14, 2950-2961. Mice - on a high-fat diet & time-restricted feeding Kohsaka, A., Laposky, A.D., Ramsey, K.M., Estrada, C., Joshu, C., Kobayashi, Y., Turek, F.W., and Bass, J. (2007). High-fat dietcdisrupts behavioral and molecular circadian rhythms in mice. Cell Metab 6, 414-421. 10.1016/j.cmet.2007.09.006. Arble, D.M., Bass, J., Laposky, A.D., Vitaterna, M.H., and Turek, F.W. (2009). Circadian timing of food intake contributes to weight gain. Obesity (Silver Spring) 17, 2100-2102. 10.1038/oby.2009.264. Vollmers, C., Gill, S., DiTacchio, L., Pulivarthy, S.R., Le, H.D., and Panda, S. (2009). Time of feeding and the intrinsic circadian clock drive rhythms in hepatic gene expression. Proc Natl Acad Sci U S A 106, 21453-21458. 10.1073/pnas.0909591106. Hatori, M., Vollmers, C., Zarrinpar, A., DiTacchio, L., Bushong, E.A., Gill, S., Leblanc, M., Chaix, A., Joens, M., Fitzpatrick, J.A., et al. (2012). Time-restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-fat diet. Cell Metab 15, 848-860. 10.1016/j.cmet.2012.04.019. Mice -Calories, Fasting & important variables influencing Lifespan Mitchell, S.J., Bernier, M., Mattison, J.A., Aon, M.A., Kaiser, T.A., Anson, R.M., Ikeno, Y., Anderson, R.M., Ingram, D.K., and de Cabo, R. (2019). Daily Fasting Improves Health and Survival in Male Mice Independent of Diet Composition and Calories. Cell Metab 29, 221-228 e223. 10.1016/j.cmet.2018.08.011. Mitchell, S.J., Madrigal-Matute, J., Scheibye-Knudsen, M., Fang, E., Aon, M., Gonzalez-Reyes, J.A., Cortassa, S., Kaushik, S., Gonzalez-Freire, M., Patel, B., et al. (2016). Effects of Sex, Strain, and Energy Intake on Hallmarks of Aging in Mice. Cell Metab 23, 1093-1112. 10.1016/j.cmet.2016.05.027. Acosta-Rodriguez, V.A., de Groot, M.H.M., Rijo-Ferreira, F., Green, C.B., and Takahashi, J.S. (2017). Mice under Caloric Restriction Self-Impose a Temporal Restriction of Food Intake as Revealed by an Automated Feeder System. Cell Metab 26, 267-277 e262. 10.1016/j.cmet.2017.06.007. Acosta-Rodriguez, V.A., Rijo-Ferreira, F., Green, C.B., and Takahashi, J.S. (2021). Importance of circadian timing for aging and longevity. Nat Commun 12, 2862. 10.1038/s41467-021-22922-6. Contact: Dr. Victoria Acosta-Rodriguez Email: ⁠victoria.acosta-rodriguez@nih.gov⁠ Twitter/X: @VickyAcostaR

46 min
11 JUL

E21 - Symposium on Circadian Rhythms & Sleep ERATO UK-Japan 2024

From the 11th to the 13th of March 2024, the 247Muscle podcast has been invited to cover the ERATO UK - Japan Joint Symposium on Circadian rhythms & Sleep, which took place at the University of Oxford. The symposium aimed to promote research exchange and collaboration in the fields of sleep and circadian clocks between the UK and Japan. In this episode, your host Frieder summarizes scientific insights from the symposium and shares short interviews conducted with speakers during the symposium. More information about the ERATO UK - Japan Joint Symposium: https://sys-pharm.m.u-tokyo.ac.jp/erato-uk/ Chapters: (00:00:54) Background of the ERATO symposium (00:02:40) Introduction by Hiroki Ueda (00:07:25) Summary of the welcome ceremony (00:10:03) Russell Foster on EEG and large sleep databases (00:12:19) Wearables to measure sleep (00:15:20) Andrew Millar on plant vs. human clocks and metabolism (00:25:05) The concept of “Arrival” for circadian research (00:36:35) Historical perspective on sleep research (00:39:47) Anne Skeldon on mathematical models for sleep (00:41:12) Koji Ode on CaMK2 (00:47:14) Hiroyuki Kanaya on anesthetics (00:49:55) Akifumi Kishi on human sleep phenotypes (00:50:44) Amin Mottahedin on stroke time (00:53:01) Alex Webb on chronoculture and space culturing (00:56:15) Sleep restriction therapy (01:00:44) Attendants and organizers sharing their highlights (01:07:48) Future perspective (01:13:17) Closing remarks (01:14:23) Sponsor: Mitsui Chemicals (01:15:54) Outro

1h 17m
25 MAR

E20 - Part 2: Fundamentals of cellular timekeeping with John O'Neill

In this second part, Dr. John O'Neill (MRC Laboratory of Molecular Biology, Cambridge) provides deep insights from his recent study on how the timing of food intake mechanistically modifies circadian clocks in cells and animals. He explains the research journey of how his group identified systemic time cues associated with food intake. John highlights the indispensable role of the vital protein kinase called mTOR for the cell to process the timing of food intake. Lastly, we discuss how the mechanistic knowledge from John's research might translate to practical eating strategies for shiftwork and jetlag. More information about the ERATO UK - Japan Joint Symposium: https://sys-pharm.m.u-tokyo.ac.jp/erato-uk/ Chapters: (0:00:11) Intro (0:02:23) Food-entrainable oscillator? (0:06:06) How insulin emerged as a suspect (0:08:38) Food timing entrains all cell clocks except for the SCN (0:10:32) What other candidates than insulin were considered? (0:12:29) How insulin modifies clocks (0:16:35) Insulin action in vitro vs. in vivo (0:25:07) Why the SCN remains mostly irresponsive to food timing (0:31:13) How conflicting time cues impair circadian organization (0:34:38) What about skipping breakfast? (0:39:07) The role of meal frequency and snacking (0:42:39) Combining time cues to support health (0:45:37) The role of mTor in daily cellular timekeeping (0:48:33) Translational perspective on shift work (0:55:15) John’s recommendations to reduce jetlag (0:58:05) John’s perspective on the ERATO symposium (1:01:20) John’s future research (1:05:20) John’s career ambitions (1:08:01) Funny anecdote (1:12:09) Outro

1h 14m
11 MAR

E19 - Part 1: Fundamentals of cellular timekeeping with John O'Neill

Dr. John O'Neill (MRC Laboratory of Molecular Biology, Cambridge), discusses his research focusing on the fundamentals of cellular timekeeping. In this first part, John explains the advantages of cells as a model to study circadian rhythms. He provides evidence of why we might consider questioning the current paradigm of how cells keep time, since his group for example demonstrated that even cells without nuclei show circadian rhythms. We further highlight a fascinating study in fibroblasts showing that wounds heal much faster when inflicted during the day vs. night. Lastly, John shares his knowledge of the vital protein kinase called mTOR, and its role in daily physiology. More information about the ERATO UK - Japan Joint Symposium: https://sys-pharm.m.u-tokyo.ac.jp/erato-uk/ Chapters: (0:00:28) Introducing ERATO UK/Japan Joint Symposium (0:03:15) This episode’s guest and content (0:05:43) Dr. John O’Neill introduces himself (0:07:46) Advantages of cells as a model to study circadian rhythms (0:11:11) Challenging our current understanding on how cells keep time (0:18:47) How do known time cues translate into cellular signals? (0:26:23) Almost or all cells in the human body have a clock? (0:29:01) Day-night rhythms in wound healing (0:37:02) mTOR’s role in physiology (0:43:23) Activators and inhibitors of mTOR (0:45:41) Daily and intrinsic rhythms in mTOR’s activity (0:46:49) Outro

50 min
13/11/2023

E18 - Part 2: Daylight vs. electric light for health with Russell Foster

In the second part with Prof. Russell Foster (Head of the Nuffield Laboratory of Ophthalmology, and Director of the Sleep and Circadian Neuroscience Institute at the University of Oxford), contributing to the Daylight Awareness Week (13-17th of November 2023), we continue our discussion around the differential impact of daylight and electric light on health. We provide a historical perspective about human inventions that aimed to end the dependency on daylight - from fire to electric lighting. Prof. Foster further shares practical recommendations on how daylight and electric light can support health and well-being. Lastly, he gives an outlook on where the research around lighting and health is heading to in the future. More information about the Daylight Awareness Week: ⁠https://daylight.academy/daylight-awareness-week-2023/ Chapters: (0:00:00) Intro & Recap of Part 1 (0:02:36) History of inventing fire & candles (0:08:22) Rise of electric light & disruption (0:15:15) Sensitivity to light at night (0:22:03) Dominance of LEDs nowadays (0:23:07) Interim conclusion (0:27:18) Practical recommendations for evening lighting (0:30:37) Architectural dilemma with daylight (0:33:12) Early birds vs. Night owls (0:37:35) Jet lag (0:40:10) Drug development for blind people (0:42:11) Mimick seasonal changes in daylight (0:45:29) Russell’s personal outlook (0:55:02) Funny anecdotes (0:59:26) Outro Papers/books that Russell refers to: A. Roger Ekirch's book: “At Day's Close” Thomas Wehr's research on bimodal or polymodal sleep: "In short photoperiods, human sleep is biphasic" (Wehr 1992) https://doi.org/10.1111/j.1365-2869.1992.tb00019.x Russell's group - investigation on international populations, night owls were missing morning light "Chronotype and environmental light exposure in a student population" (Porcheret et al. 2018) https://doi.org/10.1080/07420528.2018.1482556 Charles Czeisler’s group - full-intensity kindle watching for 4 hours for 5 nights "Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness" (Chang et al. 2014) https://doi.org/10.1073/pnas.1418490112 Prior light exposure of 500-600 lux during the day abolished the suppressing-melatonin-effect "The effects of prior light history on the suppression of melatonin by light in humans" (Hebert et al. 2002) https://doi.org/10.1034%2Fj.1600-079x.2002.01885.x Harvard group: aged humans show decreased sensitivity to light "Decreased sensitivity to phase-delaying effects of moderate intensity light in older subjects" (Duffy et al. 2007) https://doi.org/10.1016/j.neurobiolaging.2006.03.005 Christian Cajochen’s work on alertness, blue light is most important "High Sensitivity of Human Melatonin, Alertness, Thermoregulation, and Heart Rate to Short Wavelength Light" (Cajochen et al. 2005) https://pubmed.ncbi.nlm.nih.gov/15585546/ Arti Jagannath's work on jet lag: SIK1 deletion in mice and jet lag: "The CRTC1-SIK1 pathway regulates entrainment of the circadian clock" (Jagannath et al. 2013) https://doi.org/10.1016/j.cell.2013.08.004 Recent review on SIK: "The multiple roles of salt-inducible kinases in regulating physiology" (Jagganath et al. 2023) https://doi.org/10.1152/physrev.00023.2022 How to contact Russell Foster: Email: russell.foster@eye.ox.ac.uk

1h 2m

5

out of 5

2 Ratings

In the CHRONO:MEDICINE podcast (formerly known as 247Muscle), your host (Dr. Jan-Frieder Harmsen) interviews scientists, coaches and other practitioners in the field of chronobiology, circadian rhythm, skeletal muscle physiology, exercise performance and sleep. The podcast aims to provide translational knowledge from research findings for students, researchers and the generally interested public.

Creator

Dr. Jan-Frieder Harmsen
Years Active

2022 - 2024
Episodes

25
Rating

Clean
Copyright

© Dr. Jan-Frieder Harmsen
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