E8 - Part 2: How to use & avoid light to optimize health with Samer Hattar

In the second part with Dr. Samer Hattar (Chief of the Section on Light and Circadian Rhythms at the National Institute of Mental Health, Bethesda, MD, USA), we discuss:

- the concept of extraocular phototransduction, meaning how the human body can sense and adjust to light beyond the eyes

- how the eyes change upon aging and how this may affect circadian rhythms

- how light at night possibly via impaired sleep can lead to higher appetite & cravings for unhealthy food

- why "Why should I change anything? I sleep well!" people should still reduce light at night to improve health

- seasonal changes in light and their potential influence on human physiology

Link to Samer’s episode on the Hubermanlab Podcast:

Dr. Samer Hattar: Timing Light, Food, & Exercise for Better Sleep, Energy & Mood | Huberman Lab #43

https://www.youtube.com/watch?v=oUu3f0ETMJQ

Papers that Samer and I refer to:

Extraocular Circadian Phototransduction in Humans (Campbell & Murphy 1998)

https://www.science.org/doi/10.1126/science.279.5349.396?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed

Absence of Circadian Phase Resetting in Response to Bright Light Behind the Knees (Wright & Czeisler 2002)

https://www.science.org/doi/full/10.1126/science.1071697

FAILURE OF EXTRAOCULAR LIGHT TO FACILITATE CIRCADIAN RHYTHM REENTRAINMENT IN HUMANS (Eastman et al. 2000)

https://www.tandfonline.com/doi/abs/10.1081/cbi-100102116?journalCode=icbi20

Regulation of Mammalian Circadian Behavior by Non-rod, Non-cone, Ocular Photoreceptors (Freedman et al. 1999)

https://www.science.org/doi/full/10.1126/science.284.5413.502

Neuropsin (OPN5)-mediated photoentrainment of local circadian oscillators in mammalian retina and cornea (Buhr et al. 2015)

https://www.pnas.org/doi/abs/10.1073/pnas.1516259112

Opsins have also been found in adipocytes of humans and mice:

Subcutaneous white adipocytes express a light sensitive signaling pathway mediated via a melanopsin/TRPC channel axis (Ondrusova et al. 2017)

https://pubmed.ncbi.nlm.nih.gov/29180820/

Adaptive Thermogenesis in Mice Is Enhanced by Opsin 3-Dependent Adipocyte Light Sensing (Nayak et al. 2020)

https://pubmed.ncbi.nlm.nih.gov/31968245/

Differential effects of light and feeding on circadian organization of peripheral clocks in a forebrain Bmal1 mutant (Izumo et al. 2014)

https://elifesciences.org/articles/04617

Retinal innervation tunes circuits that drive nonphotic entrainment to food (Fernandez et al. 2020)

https://www.nature.com/articles/s41586-020-2204-1

Metabolic consequences of sleep and sleep loss (van Cauter et al. 2008)

https://www.sciencedirect.com/science/article/pii/S1389945708700133

Relationship between Sleep and Hedonic Appetite in Shift Workers (Vidafar et al. 2020)

https://www.mdpi.com/2072-6643/12/9/2835

Increased Hunger, Food Cravings, Food Reward, and Portion Size Selection after Sleep Curtailment in Women Without Obesity (Yang et al. 2019)

https://www.mdpi.com/2072-6643/11/3/663

NIH researcher studying sleep deprivation: Kong Chen

https://www.niddk.nih.gov/about-niddk/staff-directory/biography/chen-kong

Moonstruck sleep: Synchronization of human sleep with the moon cycle under field conditions (Casiraghi et al. 2021)

https://www.science.org/doi/full/10.1126/sciadv.abe0465

A Circannual Clock Drives Expression of Genes Central for Seasonal Reproduction (de Miera et al. 2014)

https://www.sciencedirect.com/science/article/pii/S0960982214005491

Light can activate the human prefrontal cortex:

Luxotonic signals in human prefrontal cortex as a possible substrate for effects of light on mood and cognition (Sabbah et al. 2022)

https://www.pnas.org/doi/10.1073/pnas.2118192119

Samer Hattar on Social Media:

Twitter: @SamerHattar

NIH-Homepage: https://www.nimh.nih.gov/research/research-conducted-at-nimh/principal-investigators/samer-hattar