...so I moved all my 180DegreeHealth posts here. :)
So far I have published 5 articles:
The Therapeutic Effects of Red and Near-Infrared Light (long version)
The Therapeutic Effects of Red and Near-Infrared Light (short version)
Circadian rhythms
Thyroid Hormones and Heart Disease (expanded version)
Why We Need Acid: The Dangers of Anti-acid Medication
Wednesday, November 27, 2013
Circadian rhythms, sleep and health
1. The circadian rhythm of a modern man
“In 1910, the average American slept nine hours a night, disturbed only by the occasional Model T backfiring. We now average 7.5 and declining.” – Robert Sapolsky (Why Zebras Don’t Get Ulcers)
The typical Western person’s circadian rhythm differs in at least three main ways of which the human species has adapted to in its history
First of all, the amount of light during night time. Before artificial lighting popularized, people spent the night in almost complete darkness . Today, most families live in almost constant light even if it is pitch black outside.
Second, the amount of light during the day is now lower than it has ever been in human history . The reason is that we do not spend much time outdoors. We spend the days indoors, where the amount of light can be over a hundred times less than the amount of light outside.
“Bright light can help shift even the most extreme body clocks,” says Professor Roenneberg. “But the amount of light in most offices is laughable. You would be lucky to get 400 lux [a unit of measurement of the intensity of light] at a bright vertical office window during the day, whereas outside on a cloudy day in summer you would experience more like 10,000 lux. If it’s a blue sky, you could get as much as 150,000 lux.” (Independent: Could you be suffering from ‘social jet lag’?)
The third current problem is sleep duration, which has been decreasing in recent decades.
In a study on connections between sleep and obesity published this year, it was found that in the 1960’s people slept about 8-9 hours a night. By 1995, the amount had shrunk to seven hours. In 2005, a third of the population slept for about six hours a night. Actigraphic and polysomnographic studies show that middle-aged people only get six hours of sleep on average. (Reiter et al. 2011)
Now we are going to speculate the effect of these on health by studying some research material on the subject.
2. The circadian rhythms’ connection with health – shift work and clinical sleep studies
People doing shift work is an interesting group when reflecting on the circadian rhythms’ effects on health. These people must for follow a very unnatural sleep rhythm because of their profession. Epidemiologic data shows that certain health problems are much more common among shift workers than in the average population.
“If light were a drug, the government would not approve it,” says Professor Charles Czeisler of the Harvard Medical School. And Professor George Brainard of Thomas Jefferson University in Philadelphia, adds: “Humans evolved on a planet without electric light over thousands and thousands of generations. The body is designed to be alert and awake during daytime hours and to sleep at night. Now we have a 24-7 society that isn’t in harmony with our biological design.”
“In the new study, scientists grafted human breast cancer tumours on to rats and infused them with blood taken from women during the day, in the early hours of the morning, and after being exposed to light at night. The blood taken in darkness slowed the growth of the cancers by 80 per cent, but the blood taken after exposure to light accelerated it.” (Independent: Avoid breast cancer. Sleep in the dark…)
If even a few years of shift work can clearly be seen as an elevated risk for breast cancer, could a lifetime of sleep deprivation or other light related problems that affect most people have an effect on the risk of chronic disease? I would say it’s possible.
Some experimental studies have been done, in which for example the test subjects duration of sleep has been reduced.
3. The environmental light and melatonin secretion
Next we’ll dive into the world of melatonin, but first the basics.
The ambient light contributes significantly to the body’s circadian rhythm. In particular, blue light (460-490nm) inhibits the pineal gland from secreting melatonin. Melatonin is often called the dark hormone, because it is secreted at night.
Only blue light affects the secretion of melatonin, so if a person is wearing blue blocker sunglasses, melatonin secretion will not be affected. Of course, removing the short wavelengths (blue light) from lamps will have the same effect. (Sasseville et al. 2006, Kayumov et al. 2007, Chellappa et al. 2011).
Even normal lighting before going to sleep can decrease melatonin secretion which can have effects on health. The melatonin blocking effects of blue light can be significant especially in winter time, when the small amount of daytime exposure to light can cause the body to react more significantly to bright artificial light used in the evening. (Gooley et al. 2011, Higuchi et al. 2007, Park&Tokura 1999).
Only blue wavelengths of light have effect on melatonin secretion, but for example cortisol levels can rise from other wavelengths as well. (Figueiro&Rea 2010, Leproult et al. 2001).
Below are empirical studies in which the amount or type of light has been altered and the results have been documented:
I believe that the effect seen in the bright light study mentioned before could be replicated and possibly surpassed with ordinary daylight. Expensive bright lights shine light at 10 000 lux at the best, but outside the amount of light can be ten times larger. Daylight might also have other benefits like vitamin D production caused by UV-radiation, the temporary lowering of blood pressure caused by nitric oxide metabolism, plus the stress-relieving effects of red and near-infrared light. The problem of course is, that in the winter time natural light isn’t available in large amounts in all parts of the world. (Holick et al. 2007, Opländer et al. 2009, Feelisch et al. 2010, Barrett&Gonzalez-Lima 2013).
Melatonin can also be used as medication and in clinical trials it has been portrayed as quite a useful drug:
4. Tips for improving sleep and health
Nutrition and sleep
A combination of melatonin, magnesium and zinc has been shown to have great results in sleep quality studies. (Rondanelli et al. 2011)
In a few studies, glycine has been shown to improve quality of sleep. The primary source of glycine is collagen protein or gelatin. This means that head cheese and bone broth are a good source of glycine and can improve quality of sleep. I occasionally make jelly out of gelatin and concentrated juice. (Yamadera et al. 2007, Inagawa et al. 2006)
I personally agree with the basics of Matt’s “Eat for Heat” ideology. If I have trouble falling asleep, I try to eat some extra starch and fat calories (e.g. rye/wheat bread with butter and cheese) and avoid too large amounts of fluid.
Other ideas
Seth Roberts, a Professor of Psychology, has written a lot about his various experiments, some of which are related to circadian rhythm. (Roberts 2004; Seth’s blog; Perfect Health Diet – Seth Roberts and Circadian Therapy)
Here’s a list of things that, according to Roberts’ experiments, could benefit those having problems related to their diurnal rhythm.
Acknowledgements
Thanks to Laura Mikkonen for doing most of the translating work (from Finnish to English).
Appendix I: Extra references
1989: Ford&Kamerow: Epidemiologic study of sleep disturbances and psychiatric disorders. An opportunity for prevention? “The risk of developing new major depression was much higher in those who had insomnia at both interviews compared with those without insomnia (odds ratio, 39.8; 95% confidence interval, 19.8 to 80.0).”
1995: Morita et al. Inhibitory effect of light of different wavelengths on the fall of core temperature during the nighttime.
1999: Blask et al. New actions of melatonin on tumor metabolism and growth. “Melatonin is an important inhibitor of cancer growth promotion while the essential polyunsaturated fatty acid, linoleic acid is an important promoter of cancer progression. [...] While melatonin inhibits tumor linoleic acid uptake, metabolism and growth, pinealectomy or constant light exposure stimulates these processes.“
Hébert et al. Nocturnal melatonin secretion is not suppressed by light exposure behind the knee in humans.
2000: Pinchasov et al. Mood and energy regulation in seasonal and non-seasonal depression before and after midday treatment with physical exercise or bright light. “One week of bright light treatment (2-h exposure to 2500 lux between 14.00 and 16.00 h) increased oxygen consumption in nine winter depressives and nine non-depressed subjects, while no significant change in oxygen consumption was found in nine subjects with non-seasonal depression. Weight loss was observed in the groups treated with physical exercise and in the group of light-treated winter depressives.”
2004: Claustrat et al. Melatonin secretion is supersensitive to light in migraine. “These findings show a clear hypersensitivity to light in young female migraineurs during the headache-free period.”
Mistlberger&Skene: Social influences on mammalian circadian rhythms: animal and human studies.
2005: Higuchi et al. Relationship between individual difference in melatonin suppression by light and habitual bedtime.
Barbini et al. Dark therapy for mania: a pilot study.
2006: Rybak et al. An open trial of light therapy in adult attention-deficit/hyperactivity disorder. “Morning bright light therapy was associated with a significant decrease in both subjective and objective measures of core ADHD pathology, improved mood symptoms, and a significant phase advance in circadian preference. Multiple regression showed that the shift toward an earlier circadian preference with LT was the strongest predictor of improvement on both subjective and objective ADHD measures.”
Pignone et al. Melatonin is a safe and effective treatment for chronic pulmonary and extrapulmonary sarcoidosis.
2008: Fuller et al. Differential rescue of light- and food-entrainable circadian rhythms. “When food is plentiful, circadian rhythms of animals are powerfully entrained by the light-dark cycle. However, if animals have access to food only during their normal sleep cycle, they will shift most of their circadian rhythms to match the food availability.”
2009: Kent et al. Effect of sunlight exposure on cognitive function among depressed and non-depressed participants: a REGARDS cross-sectional study. “Among depressed participants, a dose-response relationship was found between sunlight exposure and cognitive function, with lower levels of sunlight associated with impaired cognitive status (odds ratio = 2.58; 95% CI 1.43-6.69).”
Bennett et al. Use of modified spectacles and light bulbs to block blue light at night may prevent postpartum depression. “all new mothers may benefit from using glasses and light bulbs that block blue light when getting up at night to care for their babies.
Cohen et al. Sleep habits and susceptibility to the common cold. “There was a graded association with average sleep duration: participants with less than 7 hours of sleep were 2.94 times (95% confidence interval [CI], 1.18-7.30) more likely to develop a cold than those with 8 hours or more of sleep. The association with sleep efficiency was also graded: participants with less than 92% efficiency were 5.50 times (95% CI, 2.08-14.48) more likely to develop a cold than those with 98% or more efficiency.”
Schernhammer&Hankinson: Urinary melatonin levels and breast cancer risk.
Schernhammer&Hankinson: Urinary melatonin levels and postmenopausal breast cancer risk in the Nurses' Health Study cohort. "An increased concentration of urinary aMT6s was statistically significantly associated with a lower risk of breast cancer (odds ratio for the highest versus lowest quartile of morning urinary aMT6s, 0.62; 95% confidence interval, 0.41-0.95; P(trend) = 0.004)."
2010: Fonken et al. Light at night increases body mass by shifting the time of food intake
2011: Al Robaee&Alzolibani: Narrowband ultraviolet B phototherapy improves the quality of life in patients with psoriasis.
2012: Figueiro et al. Light modulates leptin and ghrelin in sleep-restricted adults.
2013: Bedrosian et al. Nocturnal Light Exposure Impairs Affective Responses in a Wavelength-Dependent Manner (pdf) “Our results demonstrate that exposure to LAN [light at night] influences behavior and neuronal plasticity and that this effect is likely mediated by ipRGCs. Modern sources of LAN that contain blue wavelengths may be particularly disruptive to the circadian system, potentially contributing to altered mood regulation.”
Fonken et al: Dim light at night exaggerates weight gain and inflammation associated with a high-fat diet in male mice.
2014: Chen et al. A randomized, placebo-controlled trial of melatonin on breast cancer survivors: impact on sleep, mood, and hot flashes.
Chottanapund et al. Anti-aromatase effect of resveratrol and melatonin on hormonal positive breast cancer cells co-cultured with breast adipose fibroblasts
Kahn et al. Effects of one night of induced night-wakings versus sleep restriction on sustained attention and mood: a pilot study. "Our pilot study indicates that, similar to sleep restriction, one night of life-like repeated night-wakings negatively affects mood and sustained attention."
Dauchy et al. Circadian and Melatonin Disruption by Exposure to Light at Night Drives Intrinsic Resistance to Tamoxifen Therapy in Breast Cancer "In this study, we used a rat model [...] Strikingly, our results also showed that melatonin acted both as a tumor metabolic inhibitor and a circadian-regulated kinase inhibitor to reestablish the sensitivity of breast tumors to tamoxifen and tumor regression."
Appendix II: Articles, forum threads etc.
Wikipedia – Phase response curves in circadian rhythms
Perfect Health Diet – Intermittent Fasting as a Therapy for Hypothyroidism
CNN: Trouble sleeping? Maybe it’s your iPad
NY TIMES: In Eyes, a Clock Calibrated by Wavelengths of Light
NY TIMES: Sleeping (or Not) by the Wrong Clock
Lowcarber Forums – Lights Out: Sleep, Sugar and Survival by T.S. Wiley (The thread is OK but I don’t recommend Wiley’s book to anyone. It’s a very poorly written book.)
Independent: Could you be suffering from ‘social jet lag’?
Slumber’s Unexplored Landscape – People in traditional societies sleep in eye-opening ways
Telegraph: This could be your dream diet
Chicago Tribune – Blue light has a dark side
Can lamps cause epileptic or other types of seizures?
Great Sleep! Reduced Cancer!: A Scientific Approach to Great Sleep and Reduced Cancer Risk (a somewhat interesting book)
LA Times: Exposure to light at night may contribute to depression, study says
Matt Metzgar: The Dark Sky Association
Matt Metzgar: Total Darkness Time
Suppversity – Circadian Rhythmicity – Sunlight, Bluelight, Backlight: How Street Lamps, iPads & Co Mess W/ Our Internal Clock. Plus: Tweaks, Tools & Apps to Prevent Negative Side-Effects
“In 1910, the average American slept nine hours a night, disturbed only by the occasional Model T backfiring. We now average 7.5 and declining.” – Robert Sapolsky (Why Zebras Don’t Get Ulcers)
The typical Western person’s circadian rhythm differs in at least three main ways of which the human species has adapted to in its history
First of all, the amount of light during night time. Before artificial lighting popularized, people spent the night in almost complete darkness . Today, most families live in almost constant light even if it is pitch black outside.
Second, the amount of light during the day is now lower than it has ever been in human history . The reason is that we do not spend much time outdoors. We spend the days indoors, where the amount of light can be over a hundred times less than the amount of light outside.
“Bright light can help shift even the most extreme body clocks,” says Professor Roenneberg. “But the amount of light in most offices is laughable. You would be lucky to get 400 lux [a unit of measurement of the intensity of light] at a bright vertical office window during the day, whereas outside on a cloudy day in summer you would experience more like 10,000 lux. If it’s a blue sky, you could get as much as 150,000 lux.” (Independent: Could you be suffering from ‘social jet lag’?)
The third current problem is sleep duration, which has been decreasing in recent decades.
In a study on connections between sleep and obesity published this year, it was found that in the 1960’s people slept about 8-9 hours a night. By 1995, the amount had shrunk to seven hours. In 2005, a third of the population slept for about six hours a night. Actigraphic and polysomnographic studies show that middle-aged people only get six hours of sleep on average. (Reiter et al. 2011)
Now we are going to speculate the effect of these on health by studying some research material on the subject.
2. The circadian rhythms’ connection with health – shift work and clinical sleep studies
People doing shift work is an interesting group when reflecting on the circadian rhythms’ effects on health. These people must for follow a very unnatural sleep rhythm because of their profession. Epidemiologic data shows that certain health problems are much more common among shift workers than in the average population.
- Obesity – In a Swedish study 27485 people answered a survey and according to the results, shift work correlates to a 40% higher risk for obesity (BMI over 30) after adjusting for age and socioeconomic factors. (Karlsson et al. 2001)
- Breast cancer – In Denmark the risk of breast cancer in nurses is 80% higher in those working day and night shifts. The longer the shift work had lasted, the larger the risk was. Those who had been working in shifts for over two years, the risk was 160% higher (after adjusting the results) than in those only working during the day. (Hansen&Stevens 2011)
- Cortisol and obesity – In the Netherlands a small study (122 persons) showed, that in people doing shift work the amount of cortisol in a hair sample was larger (47 .32 vs 29.72 pg/mg). In young people doing shift work the BMI of these people was clearly higher compared to day workers (27.2 vs 23.7). (Manenschijn et al. 2011)
- Thyroid problems – In an Italian study the thyroid levels of 220 shift workers and 442 day workers was measured. 3.8% of day workers the values showed subclinical hypothyroidism (TPO-antigens elevated and TSH over 2.51mU/l), when among shift workers the number was 7.7% – the problem is more than twice as common among shift workers than day workers. (Magrini et al. 2006 ; Perfect Health Diet – Intermittent Fasting as a Therapy for Hypothyroidism)
“If light were a drug, the government would not approve it,” says Professor Charles Czeisler of the Harvard Medical School. And Professor George Brainard of Thomas Jefferson University in Philadelphia, adds: “Humans evolved on a planet without electric light over thousands and thousands of generations. The body is designed to be alert and awake during daytime hours and to sleep at night. Now we have a 24-7 society that isn’t in harmony with our biological design.”
“In the new study, scientists grafted human breast cancer tumours on to rats and infused them with blood taken from women during the day, in the early hours of the morning, and after being exposed to light at night. The blood taken in darkness slowed the growth of the cancers by 80 per cent, but the blood taken after exposure to light accelerated it.” (Independent: Avoid breast cancer. Sleep in the dark…)
If even a few years of shift work can clearly be seen as an elevated risk for breast cancer, could a lifetime of sleep deprivation or other light related problems that affect most people have an effect on the risk of chronic disease? I would say it’s possible.
Some experimental studies have been done, in which for example the test subjects duration of sleep has been reduced.
- In a study conducted by the University of Chicago, eleven young men were sleep deprived (four hours of sleep per night) for six days. This caused the test subjects’ cortisol levels to rise and sugar tolerance to temporarily decline. (Spiegel et al. 1999)
- The same university published a cross over study, in which 10 overweight people were calorie deprived for two different time periods. During the one period they were allowed to sleep for 8.5 hours and in the other only 5.5 hours. The actual amounts of sleep were 7h 25 min and 5h 14 min. In both groups the subjects weights declined 3 kilograms, but in the sleep deprived group 80% of this weight was muscle. Without sleep deprivation 52% of the dropped weight was muscle and the rest fat. (Nedeltcheva et al. 2010 ; Whole Health Source – The Big Sleep)
- In an American study conducted in 2009, ten test subjects followed a 28 hour day instead of the normal, 24 hour day. Half way in the study the test subjects spending night time as day time, the test subjects leptin levels were about 20% lower during the day than before the test but during sleep the difference was smaller. Also the insulin levels were on average 22% higher and after breakfast (2h) the blood sugar rose 32% higher than normally. (Scheer et al. 2009)
3. The environmental light and melatonin secretion
Next we’ll dive into the world of melatonin, but first the basics.
The ambient light contributes significantly to the body’s circadian rhythm. In particular, blue light (460-490nm) inhibits the pineal gland from secreting melatonin. Melatonin is often called the dark hormone, because it is secreted at night.
Only blue light affects the secretion of melatonin, so if a person is wearing blue blocker sunglasses, melatonin secretion will not be affected. Of course, removing the short wavelengths (blue light) from lamps will have the same effect. (Sasseville et al. 2006, Kayumov et al. 2007, Chellappa et al. 2011).
Even normal lighting before going to sleep can decrease melatonin secretion which can have effects on health. The melatonin blocking effects of blue light can be significant especially in winter time, when the small amount of daytime exposure to light can cause the body to react more significantly to bright artificial light used in the evening. (Gooley et al. 2011, Higuchi et al. 2007, Park&Tokura 1999).
Only blue wavelengths of light have effect on melatonin secretion, but for example cortisol levels can rise from other wavelengths as well. (Figueiro&Rea 2010, Leproult et al. 2001).
Below are empirical studies in which the amount or type of light has been altered and the results have been documented:
- In Japan it has been noted that quite bright artificial light (5000 lux) during the day benefits digestion after dinner and that being exposed to light late at night can reduce digestion (Sone et al. 2003, Hirota et al. 2003, check also “A Zinc-less Zinc Regimen for Adults: Draft 4” on Acne.org forum).
- In Ohio the effect of blue blocker glasses and their effect on a person’s quality of sleep and mood was studied. Orange colored blue blocking glasses improved quality of sleep, but grey control glasses didn’t. (Burkhart&Phelps 2009)
- Blue blocker lenses seem to be very effective for insomnia in ADHD subjects. The average PSQI score fell “from 11.15 to 4.54, dropping below the cut-off score of 5 for clinical insomnia“. (Fargason et al. 2013)
- Doctor James Phelps described a small experiment in his article, in which persons (n=21) suffering from bipolar disorder and sleep complications were given blue blocker glasses for evening usage. Nine test subjects felt their condition improve “very much” while eight people didn’t notice any effect. Also a few felt smaller improvement and also a few were somewhat bothered because of falling asleep too early. (Phelps 2008 ; see also Seth Roberts’ blog post Bipolar Disorder: Good Results with Blue-Blocker Glasses).
- In New York State a study was conducted in which school children wore blue blocker glasses (with orange lenses) during the day for one school week. This caused their melatonin secretion at evening to begin a half an hour later than normally. (Figueiro&Rea 2010)
- Bright light treatment seems to be beneficial in the treatment of specific mood disorders, including depression and seasonal affective disorder (Golden et al. 2005, Lieverse et al. 2011).
I believe that the effect seen in the bright light study mentioned before could be replicated and possibly surpassed with ordinary daylight. Expensive bright lights shine light at 10 000 lux at the best, but outside the amount of light can be ten times larger. Daylight might also have other benefits like vitamin D production caused by UV-radiation, the temporary lowering of blood pressure caused by nitric oxide metabolism, plus the stress-relieving effects of red and near-infrared light. The problem of course is, that in the winter time natural light isn’t available in large amounts in all parts of the world. (Holick et al. 2007, Opländer et al. 2009, Feelisch et al. 2010, Barrett&Gonzalez-Lima 2013).
Melatonin can also be used as medication and in clinical trials it has been portrayed as quite a useful drug:
- Melatonin is often used as treatment for insomnia and this has been effective in especially older patients. In those children who suffer from chronic difficulties falling asleep in addition to ADHD melatonin helps relieve problems sleeping as well as ADHD symptoms. (Wade et al. 2011, Rondanelli et al. 2011, Zhdanova et al. 2001, Lemoine et al. 2007, Hoebert et al. 2009)
- In one study, melatonin had quite a good effect on irritable bowel syndrome. (Lu et al. 2005)
- Melatonin also seems to work pretty well in the treatment of heartburn and illnesses associated with it. (Pereira 2006, Kandil et al. 2010)
- Melatonin supplements might be beneficial to patients suffering from CFS and/or fibromyalgia. The benefits are possibly caused at least in part, by the improvement of subjects’ quality of sleep. Those who used melatonin showed significant improvement in sleep / sleep parameters. (Hussain et al. 2011, van Heukelom et al. 2006)
- According to a recent meta-analysis of melatonin, a slightly higher dose (20mg) seems to be have quite a large effect on conventional cancer treatments. It decreases the mortality rate and reduces treatment side effects significantly. (Wang et al. 2012, see also Mills et al. 2005)
Even though light is very important influence to human / animal circadian rhythm, apparently among light, food, other people and physical activity also have a notable effect. I’m not yet particularly familiar with that data, so it will not be discussed in this essay.
4. Tips for improving sleep and health
Get some light after waking up and during the day
The effect of light on the circadian rhythm seems to be the largest immediately after waking up, so walking outside for ten minutes after waking up can be beneficial.
If you want an adequate amount of blue light during the winter, there are roughly two types of light therapy lamps. Large ones and small ones. The larger lamps have a large lux amount (they are brighter), and the smaller ones compensate with the light spectrum and by a smaller distance between the user and lamp. The lights of small lamps are slightly bluer to compensate for the smaller intensity of light. (Meesters et al. 2011)
I have noticed that if I don’t get enough light during the first 1-2 hours after waking, I’ll stay more or less sleepy for the rest of the day.
Sufficient blue light during the day might be important for alertness, mood and sleep. (Viola et al. 2008)
Red and near-infrared light exposure might also improve sleep and increase nocturnal melatonin levels. (Zhao et al. 2012)
The effect of light on the circadian rhythm seems to be the largest immediately after waking up, so walking outside for ten minutes after waking up can be beneficial.
If you want an adequate amount of blue light during the winter, there are roughly two types of light therapy lamps. Large ones and small ones. The larger lamps have a large lux amount (they are brighter), and the smaller ones compensate with the light spectrum and by a smaller distance between the user and lamp. The lights of small lamps are slightly bluer to compensate for the smaller intensity of light. (Meesters et al. 2011)
I have noticed that if I don’t get enough light during the first 1-2 hours after waking, I’ll stay more or less sleepy for the rest of the day.
Sufficient blue light during the day might be important for alertness, mood and sleep. (Viola et al. 2008)
Red and near-infrared light exposure might also improve sleep and increase nocturnal melatonin levels. (Zhao et al. 2012)
 |
| A light box (left), blue blocker sunglasses (right). |
Avoid unnecessary light during the late evening
Turning lamps off and dimming your computer’s display are some of the simplest non-pharmaceutical ways to increase melatonin levels at night. And to make it easier to fall asleep.
If I get a too much light into my eyes at bedtime, I will suddenly become very alert and that means that I need to wait another 1-2 hours until I’ll be able to fall asleep. When I was in high school, this was a significant problem for me. I had to wake up at 7am on almost every morning, yet I usually couldn’t fall asleep before midnight. The late evening, the time when I should have been already sleeping, was the most productive time of the day, because of the strong alerting effect of light at night.
F.lux is a popular computer program that changes the displays color to orangish automatically in the evening. Personally I prefer to use Gamma Panel (gapa.exe), a program that allows you to remove blue light completely from your computer screen.
The blue blocker sunglasses are another alternative. If you want to block out blue light, you can buy some nice lenses from ebay (use keyword “aviator blue blocker”) and wear them in the evenings.
Also red light bulbs (LED) can be used can be used as night reading lamps.
Poor curtains can leave the room too bright during the night or early morning. A sleep mask is an easy and cheap way to correct this problem.
Turning lamps off and dimming your computer’s display are some of the simplest non-pharmaceutical ways to increase melatonin levels at night. And to make it easier to fall asleep.
If I get a too much light into my eyes at bedtime, I will suddenly become very alert and that means that I need to wait another 1-2 hours until I’ll be able to fall asleep. When I was in high school, this was a significant problem for me. I had to wake up at 7am on almost every morning, yet I usually couldn’t fall asleep before midnight. The late evening, the time when I should have been already sleeping, was the most productive time of the day, because of the strong alerting effect of light at night.
F.lux is a popular computer program that changes the displays color to orangish automatically in the evening. Personally I prefer to use Gamma Panel (gapa.exe), a program that allows you to remove blue light completely from your computer screen.
The blue blocker sunglasses are another alternative. If you want to block out blue light, you can buy some nice lenses from ebay (use keyword “aviator blue blocker”) and wear them in the evenings.
Also red light bulbs (LED) can be used can be used as night reading lamps.
Poor curtains can leave the room too bright during the night or early morning. A sleep mask is an easy and cheap way to correct this problem.
 |
| In the evening, I usually use Gamma Panel software to redden my computer screen. This makes falling asleep much easier. |
Nutrition and sleep
A combination of melatonin, magnesium and zinc has been shown to have great results in sleep quality studies. (Rondanelli et al. 2011)
In a few studies, glycine has been shown to improve quality of sleep. The primary source of glycine is collagen protein or gelatin. This means that head cheese and bone broth are a good source of glycine and can improve quality of sleep. I occasionally make jelly out of gelatin and concentrated juice. (Yamadera et al. 2007, Inagawa et al. 2006)
I personally agree with the basics of Matt’s “Eat for Heat” ideology. If I have trouble falling asleep, I try to eat some extra starch and fat calories (e.g. rye/wheat bread with butter and cheese) and avoid too large amounts of fluid.
Other ideas
Seth Roberts, a Professor of Psychology, has written a lot about his various experiments, some of which are related to circadian rhythm. (Roberts 2004; Seth’s blog; Perfect Health Diet – Seth Roberts and Circadian Therapy)
Here’s a list of things that, according to Roberts’ experiments, could benefit those having problems related to their diurnal rhythm.
- Morning Faces Therapy: According to Roberts, if one sees faces after waking up, he/she will be more sleepy and unmotivated in the evening, but more alert and motivated in the next morning. (1 ja 2 (p. 5-13)
 |
| A mirror, to see my own face during my piano improvisations. (Seth Roberts’ faces therapy) |
Acknowledgements
Thanks to Laura Mikkonen for doing most of the translating work (from Finnish to English).
Appendix I: Extra references
1989: Ford&Kamerow: Epidemiologic study of sleep disturbances and psychiatric disorders. An opportunity for prevention? “The risk of developing new major depression was much higher in those who had insomnia at both interviews compared with those without insomnia (odds ratio, 39.8; 95% confidence interval, 19.8 to 80.0).”
1995: Morita et al. Inhibitory effect of light of different wavelengths on the fall of core temperature during the nighttime.
1999: Blask et al. New actions of melatonin on tumor metabolism and growth. “Melatonin is an important inhibitor of cancer growth promotion while the essential polyunsaturated fatty acid, linoleic acid is an important promoter of cancer progression. [...] While melatonin inhibits tumor linoleic acid uptake, metabolism and growth, pinealectomy or constant light exposure stimulates these processes.“
Hébert et al. Nocturnal melatonin secretion is not suppressed by light exposure behind the knee in humans.
2000: Pinchasov et al. Mood and energy regulation in seasonal and non-seasonal depression before and after midday treatment with physical exercise or bright light. “One week of bright light treatment (2-h exposure to 2500 lux between 14.00 and 16.00 h) increased oxygen consumption in nine winter depressives and nine non-depressed subjects, while no significant change in oxygen consumption was found in nine subjects with non-seasonal depression. Weight loss was observed in the groups treated with physical exercise and in the group of light-treated winter depressives.”
2004: Claustrat et al. Melatonin secretion is supersensitive to light in migraine. “These findings show a clear hypersensitivity to light in young female migraineurs during the headache-free period.”
Mistlberger&Skene: Social influences on mammalian circadian rhythms: animal and human studies.
2005: Higuchi et al. Relationship between individual difference in melatonin suppression by light and habitual bedtime.
Barbini et al. Dark therapy for mania: a pilot study.
2006: Rybak et al. An open trial of light therapy in adult attention-deficit/hyperactivity disorder. “Morning bright light therapy was associated with a significant decrease in both subjective and objective measures of core ADHD pathology, improved mood symptoms, and a significant phase advance in circadian preference. Multiple regression showed that the shift toward an earlier circadian preference with LT was the strongest predictor of improvement on both subjective and objective ADHD measures.”
Pignone et al. Melatonin is a safe and effective treatment for chronic pulmonary and extrapulmonary sarcoidosis.
2008: Fuller et al. Differential rescue of light- and food-entrainable circadian rhythms. “When food is plentiful, circadian rhythms of animals are powerfully entrained by the light-dark cycle. However, if animals have access to food only during their normal sleep cycle, they will shift most of their circadian rhythms to match the food availability.”
2009: Kent et al. Effect of sunlight exposure on cognitive function among depressed and non-depressed participants: a REGARDS cross-sectional study. “Among depressed participants, a dose-response relationship was found between sunlight exposure and cognitive function, with lower levels of sunlight associated with impaired cognitive status (odds ratio = 2.58; 95% CI 1.43-6.69).”
Bennett et al. Use of modified spectacles and light bulbs to block blue light at night may prevent postpartum depression. “all new mothers may benefit from using glasses and light bulbs that block blue light when getting up at night to care for their babies.
Cohen et al. Sleep habits and susceptibility to the common cold. “There was a graded association with average sleep duration: participants with less than 7 hours of sleep were 2.94 times (95% confidence interval [CI], 1.18-7.30) more likely to develop a cold than those with 8 hours or more of sleep. The association with sleep efficiency was also graded: participants with less than 92% efficiency were 5.50 times (95% CI, 2.08-14.48) more likely to develop a cold than those with 98% or more efficiency.”
Schernhammer&Hankinson: Urinary melatonin levels and breast cancer risk.
Schernhammer&Hankinson: Urinary melatonin levels and postmenopausal breast cancer risk in the Nurses' Health Study cohort. "An increased concentration of urinary aMT6s was statistically significantly associated with a lower risk of breast cancer (odds ratio for the highest versus lowest quartile of morning urinary aMT6s, 0.62; 95% confidence interval, 0.41-0.95; P(trend) = 0.004)."
2010: Fonken et al. Light at night increases body mass by shifting the time of food intake
2011: Al Robaee&Alzolibani: Narrowband ultraviolet B phototherapy improves the quality of life in patients with psoriasis.
2012: Figueiro et al. Light modulates leptin and ghrelin in sleep-restricted adults.
2013: Bedrosian et al. Nocturnal Light Exposure Impairs Affective Responses in a Wavelength-Dependent Manner (pdf) “Our results demonstrate that exposure to LAN [light at night] influences behavior and neuronal plasticity and that this effect is likely mediated by ipRGCs. Modern sources of LAN that contain blue wavelengths may be particularly disruptive to the circadian system, potentially contributing to altered mood regulation.”
Fonken et al: Dim light at night exaggerates weight gain and inflammation associated with a high-fat diet in male mice.
2014: Chen et al. A randomized, placebo-controlled trial of melatonin on breast cancer survivors: impact on sleep, mood, and hot flashes.
Chottanapund et al. Anti-aromatase effect of resveratrol and melatonin on hormonal positive breast cancer cells co-cultured with breast adipose fibroblasts
Kahn et al. Effects of one night of induced night-wakings versus sleep restriction on sustained attention and mood: a pilot study. "Our pilot study indicates that, similar to sleep restriction, one night of life-like repeated night-wakings negatively affects mood and sustained attention."
Dauchy et al. Circadian and Melatonin Disruption by Exposure to Light at Night Drives Intrinsic Resistance to Tamoxifen Therapy in Breast Cancer "In this study, we used a rat model [...] Strikingly, our results also showed that melatonin acted both as a tumor metabolic inhibitor and a circadian-regulated kinase inhibitor to reestablish the sensitivity of breast tumors to tamoxifen and tumor regression."
Appendix II: Articles, forum threads etc.
Wikipedia – Phase response curves in circadian rhythms
Perfect Health Diet – Intermittent Fasting as a Therapy for Hypothyroidism
CNN: Trouble sleeping? Maybe it’s your iPad
NY TIMES: In Eyes, a Clock Calibrated by Wavelengths of Light
NY TIMES: Sleeping (or Not) by the Wrong Clock
Lowcarber Forums – Lights Out: Sleep, Sugar and Survival by T.S. Wiley (The thread is OK but I don’t recommend Wiley’s book to anyone. It’s a very poorly written book.)
Independent: Could you be suffering from ‘social jet lag’?
Slumber’s Unexplored Landscape – People in traditional societies sleep in eye-opening ways
Telegraph: This could be your dream diet
Chicago Tribune – Blue light has a dark side
Can lamps cause epileptic or other types of seizures?
Great Sleep! Reduced Cancer!: A Scientific Approach to Great Sleep and Reduced Cancer Risk (a somewhat interesting book)
LA Times: Exposure to light at night may contribute to depression, study says
Matt Metzgar: The Dark Sky Association
Matt Metzgar: Total Darkness Time
Suppversity – Circadian Rhythmicity – Sunlight, Bluelight, Backlight: How Street Lamps, iPads & Co Mess W/ Our Internal Clock. Plus: Tweaks, Tools & Apps to Prevent Negative Side-Effects
Thursday, November 14, 2013
The Therapeutic Effects of Red and Near-Infrared Light (2013 version)
New 2015 version of this article has been published.
Check it out.
-Vladimir
"Penetrating red light is possibly the fundamental anti-stress factor for all organisms. The chronic deficiency of such light is, I think, the best explanation for the deterioration which occurs with aging." - Raymond Peat
Check it out.
-Vladimir
"Penetrating red light is possibly the fundamental anti-stress factor for all organisms. The chronic deficiency of such light is, I think, the best explanation for the deterioration which occurs with aging." - Raymond Peat
1. Preface
During the last summer, I spent quite a lot time reading Ray Peat's articles. In many of his articles, Peat writes that darkness and blue light can be harmful for health, and red light is healthy and even crucial for well-being.
Peat doesn't give many references to justify his claims, but nevertheless, there exists a large amount of study data that seems to support his views. Some of the data is presented is this article.
2. The basic mechanism
Certain wavelengths of electromagnetic radiation directly increase ATP-levels in the tissues, mainly by activating the cytochrome c oxidase (Cox), the mitochondrial respiratory enzyme discovered by Nobel laureate Otto Warburg.[1-4] One important mechanism seems to be the photodissociation of nitric oxide, which can bind to Cox, inhibiting its ability to bind oxygen.[5-8]
The most relevant wavelengths are 600-1000nm --- in other words, red light and the penetrating shorter wavelengths of near-infrared radiation (NIR).[1]
There are important differences in the penetrating power of the different wavelengths. Visible red light doesn't penetrate tissue very well, but near-infrared does that quite well. If near-infrared is directed to the skin, the power seems to decrease 1000-fold by every 2-3 centimetres.[9,10] According to a worm study, even those very small doses seem to have an effect on the cellular level.[11] Later in this article, I will also discuss the issue that some of infrared's effects can also spread by circulation (blood cells).
When it comes to Peat's claims about blue light, high intensities can inhibit the same enzyme (Cox), and this can lead to retinal damage and other problems. I haven't examined the mechanism of inhibition.[12,13]
3. The health effects of red light and near-infrared radiation: The extent of research
Red light's positive effects on health are not a recent finding. The very earliest reports on the topic have been published in the 19th century, the most well-known article being The Red Light Treatment of Small-Pox (1895) by Niels Finsen, who also got the 1903 Nobel Prize in medicine, for his research regarding the health effects of light.[14]
In 1910, John Harvey Kellogg published his 200-page book Light Therapeutics, which included a large amount of information about the therapeutic usefulness of light therapy by incandescent light bulbs and arc lights. According to his book, light therapy can be effectively used for diabetes, obesity, chronic fatigue, insomnia, baldness, cachexia and many other health problems.[15, see also Appendix 3]
In this writing, I will focus on the contemporary research, most of which has been has been usually studied with low-level laser therapy devices (coherent light). Merely during this year, dozens of controlled human studies have been published on this subject. Many of the studies are also placebo-controlled, because low-power near-infrared light is invisible and doesn't emit heat.
According to the studies, many different illnesses can be treated with this kind of light therapy. Many of the results have been very encouraging. Here's a list of some illnesses/problems that could be, according to the studies, effectively treated with red light and/or infrared:
Acne [16]
Achilles tendinitis [17]
Angina pectoris [18]
Aphthous stomatitis [19,20]
Body contouring (weight loss) [21,22,90]
Chemotherapy-induced oral mucositis [23-26]
Cholesterol levels [27,28]
Chronic autoimmune thyroiditis [29,30]
Chronic myofascial pain in the neck [31]
Chronic rhinosinusitis [32,33]
Depression/mood [34-36]
Dry mouth / xerostomia [37,38]
Dysmenorrea [39]
Fibromyalgia [40,41]
Gingivitis [42-45]
Hand-foot-and-mouth disease [46]
Herpes labialis [47-52]
Knee osteoarthritis [53-56]
Lateral epicondylitis [57]
Lymphedema (breast cancer-related) [58,59]
Macular degeneration, age-related [60]
Male androgenetic alopecia [61,62]
Myopia (degenerative/progressive) [63]
Onychomycosis [64]
Orofacial myofunctional conditions [65]
Photoaged skin [66,67]
Pressure ulcer [68]
Raynaud's phenomenon [69]
Recovery from third molar extraction [70]
Restless legs syndrome [71,72]
Skin ulcers [73]
Sleep quality [74]
UVB-induced erythema (prevention of sunburns) [75]
Wound healing [76]
(The treatment methods vary between the studies, and this might explain varying study results.)
Many animal studies have also been contucted (see Appendix 2).
4. The health effects of red light and near-infrared radiation: A few examples of the clinical study results
Age-related macular degeneration
Researchers in the University of Heidenberg conducted a large trial of 200 subjects, in which they medicated elderly people with and without cataracts by near-infrared light (using low level laser).[60]
The intervention group was treated four times during two weeks. Placebo group was given a mock treatment.
Placebo didn't affect subject's vision, but of the patients getting infrared, 95% saw significant improvements in their vision. A large portion of the patients were able to see a few rows lower on the Snellen chart. The improved vision was maintained for 3-36 months after treatment. Four years later, the same researchers got similarly excellent results with amblyopia patients.[87]
Knee Osteoarthritis
Hungarian researchers studied the use of near-infrared light in knee osteoarthritis patients, in a double-blinded placebo controlled trial. Intervention group got infrared treatment on their affected joint twice a week, over a period of four weeks. The placebo group got a similar treatment of 100-fold lower intensity.[53]
In the intervention group, the pain scores were (on a scale from 1 to 10):
Hungarian researchers studied the use of near-infrared light in knee osteoarthritis patients, in a double-blinded placebo controlled trial. Intervention group got infrared treatment on their affected joint twice a week, over a period of four weeks. The placebo group got a similar treatment of 100-fold lower intensity.[53]
In the intervention group, the pain scores were (on a scale from 1 to 10):
- 5.75 before the treatment
- 1.71 after the last treatment session
- 1.18 two months after completing the therapy
In the placebo group, the pain scores were:
In the placebo group, the pain scores were:
- 5.62 before treatment
- 4.13 after the last treatment session
- 4.12 two months after completing the therapy
Labial herpes
The researchers of University of Vienna Medical School studied the usage of red light on labial herpes in a double-blind, placebo-controlled trial.[47]
The subjects were treated in a recurrence-free period. The intervention group were treated for 10 minutes daily for two weeks with visible red light (low-level laser). Placebo group got a similar treatment, but the laser wasn't turned on. The subjects wore masks, so that they couldn't see whether they were given the real treatment.
The patients were instructed to return to the department at the time of symptom recurrence. The median recurrence-free interval in the laser-treated group was 37.5 wk compared with 3 wk in the placebo group.
Labial herpes
The researchers of University of Vienna Medical School studied the usage of red light on labial herpes in a double-blind, placebo-controlled trial.[47]
The subjects were treated in a recurrence-free period. The intervention group were treated for 10 minutes daily for two weeks with visible red light (low-level laser). Placebo group got a similar treatment, but the laser wasn't turned on. The subjects wore masks, so that they couldn't see whether they were given the real treatment.
The patients were instructed to return to the department at the time of symptom recurrence. The median recurrence-free interval in the laser-treated group was 37.5 wk compared with 3 wk in the placebo group.
5. The systemic anti-inflammatory effect
Usually the red/near-infrared is applied locally to the treatable tissue. However, light also has systemic effects which seem to be transmitted mainly by circulation of blood. The researcher Natalya Zhevago has conducted an interesting study, in which the patients got some visible light and infrared to the sacral area (low back).[77] The given light was quite similar to sunlight, except that this light didn't contain UV radiation or blue light, and the infrared portion was polarized. According to one study, polarization of light enchances the metabolic effect slightly.[78]
The subjects' blood was analyzed after the treatment. The results were interesting. Subjects' pro-inflammatory cytokines (TNF-α, IL-6 etc.) were dramatically reduced in the subjects, especially in those with initially high values. Also, the concentrations anti-inflammatory cytokines increased.[77]
A dramatic decrease in the level of pro-inflammatory cytokines TNF-α, IL-6, and IFN-γ was revealed: at 0.5 h after exposure of volunteers (with the initial parameters exceeding the norm), the cytokine contents fell, on average, 34, 12, and 1.5 times[...]
The effects were quite opposite to the typical effects of UV radiation, which increases TNF-α ja IL-6 and other pro-inflammatory cytokines.[79] High sun-exposure is also related to increased IL-6 levels.[80]
In human studies, large doses of IL-6 and TNF-α have been demonstrated to suppress peripheral thyroid hormone metabolism by decreasing T3 and increasing rT3.[81,82] We could also speculate, whether lack of sufficient therapeutic light could be one cause of the "rT3 dominance" and hypothyroid symptoms. In two studies, half of the hypothyroid patients getting near-infrared treatment did not require any medication through the 9-month follow-up after the treatment period, somewhat establishing the importance of light for thyroid health.[29,30] Moreover, in a Russian study (Kovalyova 2002), the diabetic patients' total cholesterol was reduced from 7.98 to 5.31 in one month, a change also seen in thyroid treatments.[88,89]
6. Light sources (laser, LED, light bulbs, heat lamps, sunlight)
"Many people who came to cloudy Eugene to study, and who often lived in cheap basement apartments, would develop chronic health problems within a few months. Women who had been healthy when they arrived would often develop premenstrual syndrome or arthritis or colitis during their first winter in Eugene." - Ray Peat
In the studies conducted in recent years, red light and near-infrared have been studied mostly with coherent (laser) light devices. Some animal studies have also been conducted with light-emitting diodes (LEDs), eg. many of Janis Eells' studies.
Despite the fact that most of the studies used coherent light (laser), the coherence of the light is not a requirement for the therapeutic effects, so other light sources can be used therapeutically too. This has been stated long time ago by a leading researcher Tiina Karu, and has been confirmed in a review article by Harvard researchers.[83] And as mentioned above, J. H. Kellogg has reported the immensely effective therapeutic use of incandescent bulbs as early as in 1910 (see Appendix 3).
When I was writing my Circadian Rhythms essay, I used to think about the possible explanations of the therapeutic effects of walking outdoors. Sunlight can increase the production of vitamin D and it can also suppress melatonin, but now we have a brand new mechanism explains why it's good to spend time outdoors.
A review article on this subject states that in central Europe, the amount of IR-A radiation is limited to 20mW/cm2, which is actually quite a good amount compared to the power of the devices used in the low-level laser studies.[1] On the other hand, the wavelengths aren't optimized (to the absorption peaks) as in the laser studies, and daylight also contains UV radiation and blue light, which might reduce the benefits of red light. It should also be remembered that near-infrared radiation doesn't penetrate through the clothes.
In the indoors, halogen lamps, incandescent lamps and heat lamps are good sources of red and near-infrared light, at least if they're held close enough to the skin. Heat lamps by Philips or Osram have quite a good spectrum with low amount of blue light, but a large amount of their power is emitted as warming IR-B radiation, and only ~12% of the power is emitted as the therapeutic wavelengths (600-1000nm). However, the heat lamps are often high power (up to 250W), so they still emit quite a significant amount of therapeutic wavelengths.
Because of the phase-out of incandescent lamps, it will soon be increasingly difficult to get typical incandescent lamps of sufficient power, so in future the heat lamps might be the most practical choice. It's somewhat sad that the incandescent lamps are going to be replaced with compact fluorescent lamps (CFL), which emit some UV but only low amounts of protective red and near-infrared light. This is the reason why some of the researchers, such as Richard Funk and Alexander Wunsch, who also appeared in the Bulb Fiction documentary, have stated that increase in the CFL usage might be harmful to citizens' eyes.
The possible benefits of infrared saunas aren't usually based on this aforementioned mechanism, because most of the saunas don't emit the therapeutic wavelengths of 600-1000nm. For example, in one infrared sauna study, the sauna emitted infrared in the wavelength range of 5000-1000000 nanometres.[84]
Theoretically, LEDs and lasers with optimized wavelengths would be the best option, but to this date, the products aren't very cheap for the consumers. In theory, the optimal device emits only wavelengths of 700-950nm, so the light would be invisible and wouldn't emit any heat, but still it would produce the therapeutic health benefits by increasing the function of Cox.
7. Conclusion
The important biological effects of red light were known even back in the 19th century, yet very few of the biologists seem to know about those findings nowadays. The knowledge of the physiological effects of light is mainly limited to blue light's effects on circadian rhythm, yet the importance of red and near-infrared light is possibly even an more important topic for the public health.
The general therapeutic usefulness of red light reminds me of the therapeutic uses of thyroid hormone, the topic about which I've written before. This connection is actually quite logical, considering that thyroid hormone also increases Cox activity, by increasing the cardiolipin concentration in the mitochondria.[85,86]
Time will tell whether various treatments or lifestyle interventions based on red and near-infrared light will gain popularity in the near future. But they should, because the most of the study results are very positive*.
(*Note: There are also several trials in which results in the LLLT group were identical to placebo group (no benefit). In many cases, it's mostly about laser parameters (often a very low dose) but some results are also somewhat difficult to explain. I think I will investigate the issue during the summer 2014.)
References
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[2] Karu et al: Irradiation with He-Ne laser increases ATP level in cells cultivated in vitro. (1995)
[3] Benedicenti et al: Intracellular ATP level increases in lymphocytes irradiated with infrared laser light of wavelength 904 nm. (2008)
[4] Lapchatk et al: Transcranial near infrared laser treatment (NILT) increases cortical adenosine-5′-triphosphate (ATP) content following embolic strokes in rabbits. (2010)
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[7] Brown GC: Regulation of mitochondrial respiration by nitric oxide inhibition of cytochrome c oxidase. (2001)
[8] Nick Lane: Cell biology: Power games (2006)
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[13] Nick Lane: Are mitochondria the alpha and omega of retinal disease? (2006)
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[14] Niels R. Finsen: The Red Light Treatment of Small-Pox (1895)
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[18] Babushkina et al: Results Of 10-Year Use Of Low Intensity Laser Therapy And Conventional Treatment Of Patients With Stenocardia
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[28] Maloney et al: The reduction in cholesterol and triglyceride serum levels following low-level laser irradiation: a non-controlled, non-randomized pilot study (2009)
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[39] Shin et al: Skin adhesive low-level light therapy for dysmenorrhoea: a randomized, double-blind, placebo-controlled, pilot trial. (2012)
[40] Gür et al: Effects of low power laser and low dose amitriptyline therapy on clinical symptoms and quality of life in fibromyalgia: a single-blind, placebo-controlled trial. (2002)
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[44] Obradović et al: A histological evaluation of a low-level laser therapy as an adjunct to periodontal therapy in patients with diabetes mellitus. (2013)
[45] Makhlouf et al: Effect of adjunctive low level laser therapy (LLLT) on nonsurgical treatment of chronic periodontitis. (2012)
[46] Toida et al: Usefulness of low-level laser for control of painful stomatitis in patients with hand-foot-and-mouth disease. (2003)
[47] Schindl&Neumann: Low-intensity laser therapy is an effective treatment for recurrent herpes simplex infection. Results from a randomized double-blind placebo-controlled study. (1999)
[48] Muñoz Sanchez et al: The effect of 670-nm low laser therapy on herpes simplex type 1. (2012)
[49] Dougal&Lee: Evaluation of the efficacy of low-level light therapy using 1072 nm infrared light for the treatment of herpes simplex labialis. (2013)
[50] Ferreira et al: Recurrent herpes simplex infections: laser therapy as a potential tool for long-term successful treatment. (2011)
[51] de Carvalho et al: Effect of laser phototherapy on recurring herpes labialis prevention: an in vivo study. (2010)
[52] Eduardo Cde et al: Prevention of recurrent herpes labialis outbreaks through low-intensity laser therapy: a clinical protocol with 3-year follow-up. (2012)
[53] Hegedus et al: The effect of low-level laser in knee osteoarthritis: a double-blind, randomized, placebo-controlled trial. (2009)
[54] Gur et al: Efficacy of different therapy regimes of low-power laser in painful osteoarthritis of the knee: a double-blind and randomized-controlled trial. (2003)
[55] Stelian et al: Improvement of pain and disability in elderly patients with degenerative osteoarthritis of the knee treated with narrow-band light therapy. (1992)
[56] Alghadir et al: Effect of low-level laser therapy in patients with chronic knee osteoarthritis: a single-blinded randomized clinical study. (2013)
[57] Lam&Cheing: Effects of 904-nm low-level laser therapy in the management of lateral epicondylitis: a randomized controlled trial. (2007)
[58] Ridner et al: A pilot randomized trial evaluating low-level laser therapy as an alternative treatment to manual lymphatic drainage for breast cancer-related lymphedema. (2013)
[59] Ahmed Omar et al: Treatment of post-mastectomy lymphedema with laser therapy: double blind placebo control randomized study. (2011)
[60] Ivandic&Ivandic: Low-level laser therapy improves vision in patients with age-related macular degeneration. (2008)
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[62] Lanzafame et al: The growth of human scalp hair mediated by visible red light laser and LED sources in males. (2013)
[63] Shyrygina&Khadzhieva: [Effect of infrared low-intensity laser therapy on orbital blood circulation in children with progressive short sightedness]. (2009)
[64] Landsman et al: Treatment of mild, moderate, and severe onychomycosis using 870- and 930-nm light exposure. (2010)
[65] Melchior Mde et al: Does low intensity laser therapy reduce pain and change orofacial myofunctional conditions? (2013)
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[67] Russell et al: A study to determine the efficacy of combination LED light therapy (633 nm and 830 nm) in facial skin rejuvenation. (2005)
[68] Schubert V: Effects of phototherapy on pressure ulcer healing in elderly patients after a falling trauma. A prospective, randomized, controlled study. (2001)
[69] Hirschl et al: Low level laser therapy in primary Raynaud's phenomenon--results of a placebo controlled, double blind intervention study. (2004)
[70] Aras&Güngörmüş: The effect of low-level laser therapy on trismus and facial swelling following surgical extraction of a lower third molar. (2009)
[71] Mitchell et al: Restless legs syndrome and near-infrared light: An alternative treatment option. (2011)
[72] Mitchell et al: Comparison of two infrared devices in their effectiveness in reducing symptoms associated with RLS. (2011)
[73] Kubota J: Defocused diode laser therapy (830 nm) in the treatment of unresponsive skin ulcers: a preliminary trial. (2004)
[74] Zhao et al: Red Light and the Sleep Quality and Endurance Performance of Chinese Female Basketball Players (2012)
[75] Barolet&Boucher: LED photoprevention: reduced MED response following multiple LED exposures. (2008)
[76] Simunovic et al: Wound healing of animal and human body sport and traffic accident injuries using low-level laser therapy treatment: a randomized clinical study of seventy-four patients with control group. (2000)
[77] Zhevago&Samoilova: Pro- and Anti-inflammatory Cytokine Content in Human Peripheral Blood after Its Transcutaneous (in Vivo) and Direct (in Vitro) Irradiation with Polychromatic Visible and Infrared Light (2006)
[77] Zhevago&Samoilova: Pro- and Anti-inflammatory Cytokine Content in Human Peripheral Blood after Its Transcutaneous (in Vivo) and Direct (in Vitro) Irradiation with Polychromatic Visible and Infrared Light (2006)
[78] Barulin&Plavskii: Effect of Polarization and Coherence of Optical Radiation on Sturgeon Sperm Motility (2012)
[79] Bashir et al: UVB and proinflammatory cytokines synergistically activate TNF-alpha production in keratinocytes through enhanced gene transcription. (2009)
[80] Levandovski et al: The effect of sunlight exposure on interleukin-6 levels in depressive and non-depressive subjects. (2013)
[81] Stouthard et al: Effects of acute and chronic interleukin-6 administration on thyroid hormone metabolism in humans. (1994)
[80] Levandovski et al: The effect of sunlight exposure on interleukin-6 levels in depressive and non-depressive subjects. (2013)
[81] Stouthard et al: Effects of acute and chronic interleukin-6 administration on thyroid hormone metabolism in humans. (1994)
[82] van der Poll et al: Tumor necrosis factor: a putative mediator of the sick euthyroid syndrome in man. (1990)
[83] Chung et al: The Nuts and Bolts of Low-level Laser (Light) Therapy (2012)
[84] Oosterveld et al: Infrared sauna in patients with rheumatoid arthritis and ankylosing spondylitis. A pilot study showing good tolerance, short-term improvement of pain and stiffness, and a trend towards long-term beneficial effects. (2009)
[84] Oosterveld et al: Infrared sauna in patients with rheumatoid arthritis and ankylosing spondylitis. A pilot study showing good tolerance, short-term improvement of pain and stiffness, and a trend towards long-term beneficial effects. (2009)
[85] Paradies et al: Cardiolipin-dependent decrease of cytochrome c oxidase activity in heart mitochondria from hypothyroid rats (1997)
[86] Jakovcic et al: Biochemical and stereological analysis of rat liver mitochondria in different thyroid states (1978)
[87] Ivandic&Ivandic: Low-level laser therapy improves visual acuity in adolescent and adult patients with amblyopia. (2012)
[88] Т.В. Ковалева: Комбинированная лазерная терапия больных сахарным диабетом с дислипидеимей (2002)[89] Moshkovska&Mayberry: It is time to test low level laser therapy in Great Britain (2005)
Appendix 1: Recommended articles (+citations)
Tiina Karu: Multiple Roles of Cytochrome c Oxidase in Mammalian Cells Under Action of Red and IR-A Radiation (2010)
Healing Light Seminars - Laser Research Library
Wu&Xing: Intracellular signaling cascades following light irradiation (2013)
Hashmi et al: Effect of Pulsing in Low-Level Light Therapy (2010)
Wu&Xing: Intracellular signaling cascades following light irradiation (2013)
Hashmi et al: Effect of Pulsing in Low-Level Light Therapy (2010)
Stress reaction in outer segments of photoreceptors after blue light irradiation. (2013)
Rojas&Gonzalez-Lima: Neurological and psychological applications oftranscranial lasers and LEDs (2013)
Rojas et al: Neuroprotective effects of near-infrared light in an in vivo model of mitochondrial optic neuropathy (2008) "superoxide dismutase activities were also increased in NIL-treated subjects in a dose-dependent manner, suggesting an in vivo transcranial effect of NIL."
Light promotes regeneration and functional recovery and alters the immune response after spinal cord injury. (2005) "6% of the power of a 150 mW 810 nm laser was transmitted through all of the layers of tissue between the [adult rat] dorsal skin surface and the ventral side of the spinal cord." "PBM resulted in a significant suppression [...] of IL6 expression at 6 hours post-injury, with a 171-fold decrease in expression of IL6."
Hentschke et al: Low-level laser therapy improves the inflammatory profile of rats with heart failure. (2013) "LLLT reduced plasma IL-6 levels (61.3 %; P<0.01), TNF-α/IL-10 (61.0 %; P<0.01) and IL-6/IL-10 ratios (77.3 %; P<0.001) and increased IL-10 levels (103 %; P<0.05) in the 21 J/cm(2)-HF group. Moreover, LLLT reduced the TNF-α (20.1 % and 21.3 %; both P<0.05) and IL-6 levels (54.3 % and 37.8 %; P<0.01 and P<0.05, respectively)"
Fukuda et al: Infrared low-level diode laser on inflammatory process modulation in mice: pro- and anti-inflammatory cytokines. (2013) "The low-level laser application decreased the TNF-α and IFN-γ release in vivo of spleen mononuclear cells in mice, especially after two exposure sessions. However, there was no modulation of the IL-6 and TGF-β1 release."
Chung et al: The Nuts and Bolts of Low-level Laser (Light) Therapy (2012) "It was originally believed that the coherence of laser light was crucial to achieve the therapeutic effects of LLLT, but recently this notion has been challenged by the use of LEDs, which emit non-coherent light over a wider range of wavelengths than lasers. It has yet to be determined whether there is a real difference between laser and LED, and if it indeed exists, whether the difference results from the coherence or the monochromaticity of laser light, as opposed to the non-coherence and wider bandwidth of LED light."
Eells et al: Mitochondrial signal transduction in accelerated wound and retinal healing by near-infrared light therapy. (2004) "These findings provide a link between the actions of red to near infrared light on mitochondrial oxidative metabolism in vitro and cell injury in vivo. Based on these findings and the strong evidence that mitochondrial dysfunction is involved in the pathogenesis of numerous diseases processes, we propose that NIR-LED photobiomodulation represents an innovative and non-invasive therapeutic approach for the treatment of tissue injury and disease processes in which mitochondrial dysfunction is postulated to play a role including diabetic retinopathy, age-related macular degeneration, Leber's hereditary optic neuropathy and Parkinson's disease."
Kim et al: Near-infrared light and expectancy effects on maximal isokinetic strength performance: a randomized, double-blind, placebo-controlled study. (2006) "Individuals in active conditions were outfitted in NIR light-emitting bandages, T-shirts, and socks[...]"
Havelock Ellis: Sexual Education and Nakedness (1909) "The hygienic value of nakedness is indicated by the robust health of the savage throughout the world who go naked. The vigor of the Irish, also, has been connected with the fact that (as Fynes Moryson's Itinerary shows) both sexes, even among persons of high social class, were accustomed to go naked except for a mantle, especially in more remote parts of the country, until the sevcenteeth century. Wherever primitive races abandon nakedness for clothing, at once the tendency to disease, mortality, and degeneracy notably increases, though it must be remembered that the use of clothing is commonly accompanied by the introduction of other bad habits.“
Lindqvist et al: Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort (2014) "The mortality rate amongst avoiders of sun exposure was approximately twofold higher compared with the highest sun exposure group"
Grimes et al: Sunlight, cholesterol and coronary heart disease. (1996) "the increased concentration of blood cholesterol during the winter months, confirmed in this study, may well be due to reduced sunlight exposure"
Al-Tamer et al: Seasonality of Hypertension (2008) "These results suggest that in areas where significant changes in day temperature and daylight duration exist at different times of the year, blood pressure, serum cholesterol, and HDL-C levels change accordingly in a cycle with higher blood pressure and serum total cholesterol and lower HDL-C values in the coldest season."
Argani&Javanshir: Seasonal variations of blood pressure in hemodialysis and renal transplant recipients. (2004) "We conclude that [blood pressure] and [body weight] are decreased in warmer seasons in both HD and RTX patients."
University of Milwaukee - Light as medicine? UWM researchers explain how
Mironava et al: The effects of UV emission from compact fluorescent light exposure on human dermal fibroblasts and keratinocytes in vitro. (2012) "The data presented herein confirm that higher than expected levels of UVA and UVC irradiation can be emitted by commercially available CFL bulbs as a result of the limitation of the current production process and the possible physical defects in the bulbs where the phosphorus coating was compromised. Skin cells exposed to the CFL exhibit 25% and 50% attrition for DO33 and CF-29, respectively. For the surviving cells, a significant increase in the production of ROS, and in the case of the CF-29, a decrease in their ability to contract collagen and abnormal migration behavior, are observed and consistent with previous reports of exposure to UVA and UVC radiation.
[...]
Illumination of all cell to incandescent light (where no UV emissions were detected), had no significant effect on proliferation, ROS production, or mitochondrial activity. Taken together, our results confirm that UV radiation emanating from CFL bulbs (randomly selected from different suppliers) as a result of defects or damage in the phosphorus coating is potentially harmful to human skin."
Rojas&Gonzalez-Lima: Neurological and psychological applications oftranscranial lasers and LEDs (2013)
Rojas et al: Neuroprotective effects of near-infrared light in an in vivo model of mitochondrial optic neuropathy (2008) "superoxide dismutase activities were also increased in NIL-treated subjects in a dose-dependent manner, suggesting an in vivo transcranial effect of NIL."
Light promotes regeneration and functional recovery and alters the immune response after spinal cord injury. (2005) "6% of the power of a 150 mW 810 nm laser was transmitted through all of the layers of tissue between the [adult rat] dorsal skin surface and the ventral side of the spinal cord." "PBM resulted in a significant suppression [...] of IL6 expression at 6 hours post-injury, with a 171-fold decrease in expression of IL6."
Hentschke et al: Low-level laser therapy improves the inflammatory profile of rats with heart failure. (2013) "LLLT reduced plasma IL-6 levels (61.3 %; P<0.01), TNF-α/IL-10 (61.0 %; P<0.01) and IL-6/IL-10 ratios (77.3 %; P<0.001) and increased IL-10 levels (103 %; P<0.05) in the 21 J/cm(2)-HF group. Moreover, LLLT reduced the TNF-α (20.1 % and 21.3 %; both P<0.05) and IL-6 levels (54.3 % and 37.8 %; P<0.01 and P<0.05, respectively)"
Fukuda et al: Infrared low-level diode laser on inflammatory process modulation in mice: pro- and anti-inflammatory cytokines. (2013) "The low-level laser application decreased the TNF-α and IFN-γ release in vivo of spleen mononuclear cells in mice, especially after two exposure sessions. However, there was no modulation of the IL-6 and TGF-β1 release."
Chung et al: The Nuts and Bolts of Low-level Laser (Light) Therapy (2012) "It was originally believed that the coherence of laser light was crucial to achieve the therapeutic effects of LLLT, but recently this notion has been challenged by the use of LEDs, which emit non-coherent light over a wider range of wavelengths than lasers. It has yet to be determined whether there is a real difference between laser and LED, and if it indeed exists, whether the difference results from the coherence or the monochromaticity of laser light, as opposed to the non-coherence and wider bandwidth of LED light."
Eells et al: Mitochondrial signal transduction in accelerated wound and retinal healing by near-infrared light therapy. (2004) "These findings provide a link between the actions of red to near infrared light on mitochondrial oxidative metabolism in vitro and cell injury in vivo. Based on these findings and the strong evidence that mitochondrial dysfunction is involved in the pathogenesis of numerous diseases processes, we propose that NIR-LED photobiomodulation represents an innovative and non-invasive therapeutic approach for the treatment of tissue injury and disease processes in which mitochondrial dysfunction is postulated to play a role including diabetic retinopathy, age-related macular degeneration, Leber's hereditary optic neuropathy and Parkinson's disease."
Kim et al: Near-infrared light and expectancy effects on maximal isokinetic strength performance: a randomized, double-blind, placebo-controlled study. (2006) "Individuals in active conditions were outfitted in NIR light-emitting bandages, T-shirts, and socks[...]"
Havelock Ellis: Sexual Education and Nakedness (1909) "The hygienic value of nakedness is indicated by the robust health of the savage throughout the world who go naked. The vigor of the Irish, also, has been connected with the fact that (as Fynes Moryson's Itinerary shows) both sexes, even among persons of high social class, were accustomed to go naked except for a mantle, especially in more remote parts of the country, until the sevcenteeth century. Wherever primitive races abandon nakedness for clothing, at once the tendency to disease, mortality, and degeneracy notably increases, though it must be remembered that the use of clothing is commonly accompanied by the introduction of other bad habits.“
Lindqvist et al: Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort (2014) "The mortality rate amongst avoiders of sun exposure was approximately twofold higher compared with the highest sun exposure group"
Grimes et al: Sunlight, cholesterol and coronary heart disease. (1996) "the increased concentration of blood cholesterol during the winter months, confirmed in this study, may well be due to reduced sunlight exposure"
Al-Tamer et al: Seasonality of Hypertension (2008) "These results suggest that in areas where significant changes in day temperature and daylight duration exist at different times of the year, blood pressure, serum cholesterol, and HDL-C levels change accordingly in a cycle with higher blood pressure and serum total cholesterol and lower HDL-C values in the coldest season."
Argani&Javanshir: Seasonal variations of blood pressure in hemodialysis and renal transplant recipients. (2004) "We conclude that [blood pressure] and [body weight] are decreased in warmer seasons in both HD and RTX patients."
University of Milwaukee - Light as medicine? UWM researchers explain how
Mironava et al: The effects of UV emission from compact fluorescent light exposure on human dermal fibroblasts and keratinocytes in vitro. (2012) "The data presented herein confirm that higher than expected levels of UVA and UVC irradiation can be emitted by commercially available CFL bulbs as a result of the limitation of the current production process and the possible physical defects in the bulbs where the phosphorus coating was compromised. Skin cells exposed to the CFL exhibit 25% and 50% attrition for DO33 and CF-29, respectively. For the surviving cells, a significant increase in the production of ROS, and in the case of the CF-29, a decrease in their ability to contract collagen and abnormal migration behavior, are observed and consistent with previous reports of exposure to UVA and UVC radiation.
[...]
Illumination of all cell to incandescent light (where no UV emissions were detected), had no significant effect on proliferation, ROS production, or mitochondrial activity. Taken together, our results confirm that UV radiation emanating from CFL bulbs (randomly selected from different suppliers) as a result of defects or damage in the phosphorus coating is potentially harmful to human skin."
Appendix 2: Animal studies (with positive results)
Dogs: time to ambulation in dogs after hemilaminectomy (14d vs 3.5d), myocardial infarction, sperm motility(!!!)
Mice: traumatic brain injury, myonecrosis induced by Bothrops jararacussu snake venom, experimental autoimmune encephalomyelitis1 2
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