Your host Frieder introduces the topic of light and its influence on human physiology. Properties of light, such as the visible wavelength spectrum of light as well as ultra-violett (UV) and infrared light, are described. Differences between natural daylight and electric artificial light are pointed out. Time-of-day dependency of the influence of light on physiology is highlighted with a special focus on the secretion of the "darkness hormone" melatonin. Practical recommendations on how 24h light exposure can support wakefulness, sleep and overall health are mentioned and will be further discussed in the upcoming episodes with future guests. Frieder also presents his recent study on how an indoor 24h light scheme mimicking the natural light/dark cycle more closely influences metabolic health and thermoregulation in older volunteers with pre-diabetes.
Main paper that I discuss:
The influence of bright and dim light on substrate metabolism, energy expenditure and thermoregulation in insulin-resistant individuals depends on time of day
https://doi.org/10.1007/s00125-021-05643-9
Other papers and resources that I refer to :
The MyLux app for smartphones is to my surprise not available anymore when I checked the appstore, but my explanations on its use and limitations would apply to any other lux-measuring app as they all measure lux via the smartphone-integrated camera.
Dr. Samer Hattar: Timing Light, Food, & Exercise for Better Sleep, Energy & Mood | Huberman Lab #43
https://www.youtube.com/watch?v=oUu3f0ETMJQ&ab_channel=AndrewHuberman
High sensitivity and interindividual variability in the response of the human circadian system to evening light
https://www.pnas.org/doi/full/10.1073/pnas.1901824116
The effects of prior light history on the suppression of melatonin by light in humans
https://onlinelibrary.wiley.com/doi/epdf/10.1034/j.1600-079X.2002.01885.x
Acute Effects of Morning Light on Plasma Glucose and Triglycerides in Healthy Men and Men with Type 2 Diabetes
https://doi.org/10.1177/0748730417693480
Melatonin Effects on Glucose Metabolism: Time To Unlock the Controversy
https://doi.org/10.1016/j.tem.2019.11.011
Functional link between distal vasodilation and sleep-onset latency?
https://doi.org/10.1152/ajpregu.2000.278.3.R741
Diurnal Blood Pressure Variations Are Associated with Changes in Distal–Proximal Skin Temperature Gradient
https://doi.org/10.3109/07420528.2012.719961
Effects of dim or bright-light exposure during the daytime on human gastrointestinal activity.
https://doi.org/10.1081/CBI-120017688
Increase in parasympathetic nerve activity during the nighttime following bright light exposure during the daytime.
https://doi.org/10.1076/brhm.34.3.233.18809
Salivary secretion under the influence of bright/dim light exposure in the morning
https://doi.org/10.1076/brhm.33.2.129.1316
