Blue Light
Episodes
In this clip, Dr. Matthew Walker explains how altering the timing and duration of daytime light exposure influences sleep.
In this clip, Dr. Satchin Panda discusses factors that determine our daily energy fluctuations and how we can counteract low periods.
In this clip, Dr. Satchin Panda describes how managing our indoor lighting can regulate circadian rhythms and counteract the detrimental health effects of our modern lifestyles.
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In this clip, Dr. Matthew Walker explains how altering the timing and duration of daytime light exposure influences sleep.
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In this clip, Dr. Satchin Panda discusses factors that determine our daily energy fluctuations and how we can counteract low periods.
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In this clip, Dr. Satchin Panda describes how managing our indoor lighting can regulate circadian rhythms and counteract the detrimental health effects of our modern lifestyles.
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In this clip, Dr. Satchin Panda explains how light exposure affects the circadian clock and how dimming lights and avoiding devices in the evening allows melatonin to rise naturally.
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In this clip, Dr. Satchin Panda summarizes tips and strategies that anyone can follow to ensure a healthy circadian clock.
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In this clip, Dr. Roger Seheult explains the different parts of sleep and the value of each phase.
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Dr. Charles Raison discusses how exposure to light during the day and maintaining a dark environment at night, is important in depression management.
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Dr. Matthew Walker describes the negative effects of blue light exposure on melatonin production and sleep.
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Dr. Matthew Walker describes critical factors that influence healthy sleep patterns, including the intake of caffeine, alcohol, and other substances.
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Nutrition Vitamin D Metabolism Diabetes Telomeres Omega-3 Inflammation Depression DNA Damage Stem Cells Micronutrients Mitochondria Autophagy Autism Schizophrenia Resveratrol Sulforaphane Insulin Blue LightDr. Rhonda Patrick makes her fifth appearance on the Joe Rogan Experience.
Topic Pages
News & Publications
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Circadian rhythms regulate metabolic processes, including glucose metabolism and insulin sensitivity. Disruptions in circadian rhythms can lead to metabolic impairments, increasing the risk of obesity, type 2 diabetes, and metabolic syndrome. A recent study found that personal light exposure patterns predict the risk of developing type 2 diabetes.
Researchers assessed the light exposure patterns of more than 84,000 UK Biobank participants. Participants wore light sensors for one week to record their day and night light exposure. The researchers tracked the incidence of type 2 diabetes among the participants over an average follow-up period of nearly eight years.
They found that diabetes risk increased as night light exposure increased. Compared to low light exposure, the risk of diabetes increased by - 29 percent with moderate light exposure. - 39 percent with high-moderate light exposure. - 53 percent with high light exposure. The increased risk associated with night light exposure was comparable to the difference between people with low and moderate genetic risk for diabetes.
These findings suggest that nighttime light exposure is a risk factor for developing type 2 diabetes, comparable to genetic risk factors. Interestingly, low solar angle light – as in the early morning or late evening – resets the body’s circadian rhythms, improving metabolic health and mood. Learn more about low solar angle light exposure in this episode featuring Dr. Andrew Huberman.
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Excess artificial light exposure increases risk of obesity in preschool aged children www.sciencedaily.com
Artificial light exposure increases the risk for obesity among children. Light is the primary signal that entrains the body’s master clock to set its 24-hour circadian cycle. Consequently, the body is synchronized to external light-dark cycles. In recent decades, exposure to light from artificial sources (rather than natural ones) has increased, paralleling the global increases in obesity among adults. Findings from a 2016 study suggest that exposure to artificial light increases the risk for obesity among children.
Global health experts estimate that more than 42 million children under the age of five years have obesity, roughly one-fourth of whom live in developing nations. Obesity increases a person’s risk for developing chronic diseases such as type 2 diabetes, heart disease, and some cancers. It also imposes considerable financial costs at the individual, healthcare system, and national level.
The study involved 48 preschool-aged children receiving daycare services in Australia. The investigators measured the children’s baseline body mass index (BMI), sleep duration and timing, light exposure, and physical activity levels via clinical assessment, parent questionnaires, and light and activity trackers. They repeated these measures 12 months later.
They found that at baseline, children who had longer early exposure to moderate intensity light (such as that from artificial sources) were more likely to have higher BMI, while children who had longer afternoon exposure to bright light (such as that from natural sources) tended to have lower BMI. At the second assessment, the investigators found that even after taking into account sleep duration and timing, BMI, and activity levels, children who had more total light exposure at baseline (due to having earlier exposure) gained more weight than their peers. Specifically, for every hour earlier that the children were exposed to light, they experienced a 0.6 unit increase in BMI. The investigators posited that although this was a small increase, it could be an indicator of a life-long trajectory toward weight gain.
These findings suggest that greater light exposure, especially when it occurs early in the day from artificial light sources, contributes to weight gain in children. Interestingly, adults that receive early exposure to bright light typically sleep better – a key to maintaining a healthy weight. Learn more in this clip featuring Dr. Matthew Walker.
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Less blue-light exposure at night improves metabolism. www.sciencedaily.com
Inorganic light-emitting diodes – better known as LEDs – are ubiquitous in the modern era. Found in cell phones, televisions, computer screens, and a host of other electronic devices, LEDs emit short-wave, high-energy blue light, which has been linked to a wide range of harmful effects on health and sleep. Findings from a recent study suggest that organic LEDs (OLEDs), which produce less light in the blue-wave spectrum, have fewer harmful effects on human metabolism.
Light exposure is one of the primary regulators of the body’s circadian rhythms and plays key roles in sleep quantity and quality. For example, evidence indicates that afternoon exposure to blue light impairs the release of melatonin – the “sleepiness hormone” – in a dose-dependent manner. Similarly, use of LED-lit devices in the evening interferes with sleep by promoting alertness.
The cross-over study involved ten healthy males (average age, 25 years) who did not have sleep disorders. The participants were exposed to either LED, OLED, or dim light for four hours prior to going to sleep. The study investigators assessed the participants' sleep quality via polysomnography as well as the participants' self-assessment. The participants ate breakfast one hour after waking up, and the authors measured the participants' energy expenditure, fat oxidation, core body temperature, and melatonin levels for four hours (continuously) in a room with regular lighting. Each of the participants underwent all three lighting scenarios.
The investigators found that after OLED exposure, the participants' energy expenditure and core body temperature during sleep were lower than after LED exposure, but their fat oxidation was higher. In addition, the increase in fat oxidation following OLED exposure was associated with higher melatonin levels. Sleep quality did not differ markedly between the different lighting scenarios.
These findings suggest that evening OLED exposure elicits fewer harmful health effects than LED exposure, likely because OLEDs emit less blue light. Learn more about the effects of blue light in this clip featuring sleep expert Dr. Matthew Walker.
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After exposure to daytime bright light (6.5 hours), evening use of a tablet for two hours did not affect sleep in healthy young students. www.sciencedaily.com
Getting bright light throughout the day could be just as important for improving sleep as avoiding blue light exposure at night.
After exposure to daytime bright light (6.5 hours), evening use of a tablet for two hours did not affect sleep in healthy young students.
The evening tablet use did not affect sleepiness and saliva melatonin levels before sleep, nor did it change the time to fall asleep or subsequent sleep. It has previously been shown that early bright light exposure can ameliorate some of the suppressive effects of evening blue light has on melatonin levels.
To learn more about the importance of early bright light exposure on improving sleep quality, check out my podcast with Dan Pardi that talks about a lot of interesting points relevant to this…
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You probably already know that ambient light regulates circadian rhythms by interacting with light-sensitive neurons in the eye.
But let’s review anyway: In full white light (which contains all colors of light), the rays of the blue and green light spectrum activate melanopsin, a photosensitive protein in specific cells of the retina in the back of the eye. When light hits these cells, a signal transmits information to the brain’s master clock. By detecting various intensities and tones of light, the brain can keep track of what time of day it is.
This is relatively well established. We also know that sunlight can stimulate the production of vitamin D and nitric oxide, both of which have important effects on health. But are these all of the effects that light has on our physiology?
It has been known for several decades that a small percentage of blue light can penetrate human skin, and can even reach white subcutaneous adipose tissue. But the relevance of this finding on our physiology was not obvious.
Curiously, it has also been reported that high OPN4 (the gene that encodes the photopigment melanopsin) mRNA levels are found in human subcutaneous fat. Kind of weird: what the heck are these light-sensitive eye proteins doing in our fat tissue? Additionally, we now know that fat cells contain transient receptor potential cation (TRPC) channels – membranes that are found in the retina that open in response to varying intensities of light.
So, we know that blue light can get to subcutaneous fat tissue, and fat cells seem to have the machinery needed to respond to the signal that is transmitted by light. Very interesting. Is it possible that visible light penetrates the skin, and exerts physiological effects by activating a melanopsin / TRPC channel signaling pathway in human fat? And if so, could exposure to visible light have an impact on the regulation of body fat? The answer appears to be yes.
My guest in this episode (inadvertently) found the answer to this novel questions…
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People that have their deep sleep cycle disrupted for one night experience a 10% increase in amyloid plaque levels. www.sciencedaily.com
People that have their deep sleep cycle (slow-wave cycle) disrupted for one night experience a 10% increase in amyloid plaque levels compared to when their deep sleep cycle is uninterrupted.
Amyloid beta plaques accumulate outside of neurons in the brain and disrupt synapses (the connections between two neurons that form memories) and is just one way that memory loss occurs in Alzheimer’s disease.
This study showed that slow-wave sleep, which is the deep sleep that people need to wake up feeling rested, is important for preventing the accumulation of amyloid plaques. While a few nights of disrupted sleep is likely not a problem, it is the chronic disrupted slow-wave sleep (ie. sleep apnea) that may put a person at increased risk for Alzheimer’s disease.
A few things that I have found improve my sleep are switching all blue lights off before sunset since blue light stops the production of melatonin. I have red lights that turn on before sunset and this has really helped my sleep pattern. Also, a bright light exposure first thing in the morning to start my circadian clock has really helped. Lastly, following a time-restricted eating pattern where I do not eat 4 hours before bed and a cold/quiet room also make a huge difference.
My podcast with Dr. Satchin Panda discusses the importance of dark/light and food timing in sleep. Dr. Satchin Panda podcast: https://youtu.be/-R-eqJDQ2nU
My podcast with Dan Pardi also discusses ways to optimize sleep. Dan Pardi podcast: video: https://youtu.be/VhMjrWlWhLU