A couple of years ago, I started reading material about light, darkness, and stress. I learned, from Ray Peat, that darkness is stressful and blue light is toxic, damaging the mitochondria and the enzyme cytochrome oxidase.
Darkness damages mitochondria and as a result it reduces the conversion from cholesterol to pregnenolone, and that, alone, can cause serious stress, hypothyroidism, weight gain, and other syndromes.
Let me focus on this quote for a bit:
“When I moved from Mexico, first to Montana and then to Oregon in 1966, I became very conscious of how light affects the hormones and the health. (For example, in Montana I experienced an interesting springtime shedding of body hair.) 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, PhD
I bolded the cheap basement apartments part for a reason. A couple months ago, when I got back to Mexico, the first place I lived in was an apartment I rented for a few days. My plan was to move to a better place when I found one to my liking. This was a “cheap apartment” indeed and was poorly lit. Very little daylight found its way into that apartment even though the weather was pretty sunny even in the winter.
Within a couple days, I noticed a change in my hormones and started feeling stressed and down. It was so bad that I had to change my reservation and find another place to stay. By this time, I was very conscious of how living in poorly lit places affect our hormonal status. When I moved to a place where daylight filled the apartment, I stopped feeling stress from it.
In the absence of light, be it daylight or even artificial light, cortisol increases, and the production of protective hormones decreases. The cortisol-estrogen/testosterone-DHEA-progesterone ratio, for example, increases.
For the last several years, in Italy, I noticed I would get fatter, lethargic and depressed in winter and leaner and happier in the summer, without changing much in my diet and lifestyle. It was then I realized, I was stressed by darkness, and energized by the presence of daylight. There was a direct correlation in the way I felt based on how much light I had on that day, and how many daylight hours in general were present in that particular place, in a particular season. I also noticed changes in my thought patterns between the day and night. The same thought or challenge seemed more possible in a positive way during a sunny day. Counter to that, I realized I thought in a more negative, destructive and paranoid way in the dark of night, or during patterns of cloudy days. Similar patterns can be noticed between the seasons, besides day and night cycles.
Sunlight, Energy, Vitamin D, Dangers
Sunlight is the main natural source of light. I think it’s important to distinguish the various actions of sun; sunny weather, direct sunlight exposure, and vitamin D levels.
Sunny weather promotes energy levels and metabolism, even without direct exposure; it helps keeping the blood sugar up and the cells in the stable, high-energy state, rather than the unproperly excited one. The light, orange and red wavelengths present in the sunlight spectrum seem to be responsible for that.
“Although exposure to sun does contribute to aging of the skin,
people who spend years working outdoors have a reduced incidence of
cancer of internal organs. It turns out that daylight
stimulates our ability to use oxygen for energy production, and
protects our tissues from some of the free-radical toxins that are
produced by normal metabolism, by stress, or by radiation.” Ray Peat, PhD
The amount of sunshine hours in the climate, and how they are distributed, are certainly an important factor to take into account. People seem to be healthier when it’s consistently sunny; germs are quickly killed by exposure to sunlight, especially at high altitude, so sunny climates more often get a natural disinfecting action.
Direct sunlight exposure has a range of effects, as the sunlight spectrum provides various types of rays of different wavelengths–orange, red, UV, etc.
One time in Mexico I was feeling so lethargic and fatigued, so I decided to expose my whole body to the high altitude strong sunlight for a few minutes, wondering that could help. That same day, maybe in a hour or so, I had an immediate energizing effect and could be productive to my daily activities; it had a dramatic, sudden effect, but that same night I had insomnia and would feel hyperactive, with adrenergic and sympathetic over-activity. I also noticed that it sharply increased my body odors.
The penetrating red wavelengths increase CO2 production and useful energy, the UV activates adrenergic nerves and cholesterol and vitamin D synthesis. Vitamin D improves energy and protects against excess sympathetic/adrenergic activity. 
It seems to be the regulation of calcium metabolism to have a stabilizing effect. Supplementing vitamin D can help the tanning process go in the right direction, protecting against the excess sympathetic activity. Raymond Peat, PhD, recommends a vitamin D level in the blood to be in about the middle of the range, 50-55ng/ml, which seems to very much agree with the levels recommended by the Vitamin D Council.
While it’s good to produce vitamin D by exposing ourselves to the sun, we should not forget that UV radiations are ionizing and age the skin. At high altitude it requires much less time to produce vitamin D, but it also takes less time to get sunburned. In the summer, on an equatorial mountain, it might take only a few minutes to produce a valuable amount of vitamin D, but in other places much longer exposure is needed. In the skin, vitamin A, carotene, riboflavin, folic acid, and unsaturated fats are oxidized by UV, and some of the toxins enter the circulation, activating stress reactions. Prostaglandins, isoprostanoids and oxidation products including acrolein and malondialdehyde are probably among the most harmful substances, favoring the production of nitric oxide. 
If one’s will is to raise vitamin D levels by sunlight exposure, I recommend exposing the whole body for 15-20 minutes everyday at sea level, less if the altitude is considerably high, for a week or two, to start the tanning process. As mentioned, supplementing a little vitamin D, as well as using aspirin. Blood tests for vitamin D are useful.
Aspirin has a wide range of protective actions against sunlight; it reduces free fatty acids and iron in the serum, mitigating free radical damage. Other than the preventive effect, it seems to reduces the damage even when taken afterward, reducing prostaglandings and nitric oxide.
Using Artificial Light – A Practical Approach
The best way to deal with this and mitigate/minimize the stress caused by darkness is by using artificial lights from sunset to bedtime. This is particularly important in winter in high latitude places. You want to shoot for at least 12 hours of light. If you live in a poorly lit apartment or house, try to notice if it’s affecting your hormones. If the winter in your city is cloudy and rainy, you may want to use those lights even during the day. to keep your area warm, substituting it for the other heating method you’re using.
Now, let’s discuss light spectrums. You want to minimize toxic blue light. And you want to maximize red and orange wavelengths, because those are the ones that activate and repair the cytochrome oxidase enzyme and stop the stress darkness-related reaction.
Fluorescent bulbs are very common nowadays, but their spectrum doesn’t seem very favorable, and it isn’t a continuous one. Incandescent bulbs have the best ration of red, orange to blue wavelengths. Daylight has probably the most variety. LED can offer a particularly useful wavelength, or many of them, but it doesn’t have the variety of the full incandescent spectrum, which I believe is safer and very important to have.
In my experience, and according to Ray Peat, PhD, you need several hundred watts to stop the stress reaction at night. I think at very least 500w of incandescent light is needed, but it is better to have more, up to 1000w. Bare skin is preferable, at least for a few times, so that it can penetrate tissue. It isn’t necessary, though. Maybe a few minutes here and there, if you’re not working.
There are generally two types of bulbs that emit incandescent light. One is the most classic bulb, and the one that comes to mind when you think of a bulb. That is this:
The spectrum emitted by those bulbs is good, but they aren’t very practical to use since you don’t have anything to reflect the light to a particular area. In addition, you would need several hundred watts in order to make a difference and stop the stress reaction.
I’m not saying they are a bad option, but there’s a better one, that is the “brooder lamps” used on chicken farms and other commercial purposes.
They are something like this:
The lamp consists of two parts, the reflector, and the bulb. Those are the bulbs you need; 250w, 375w or even 500w are available. However, standard reflectors used for chickens generally tolerate up to 250w, which is fine and the most practical.
Keep in mind that most likely they will be labeled as “infrared bulbs”, but if they have a clear glass, they will emit incandescent and near-IR light, which is what we’re looking for. Do not buy those bulbs with red glass because they won’t serve your purpose.
You just put the bulb into the reflector. Use at least two of them, but 3 or 4 would be better, though there’s the problem of overheating. Of course, your finances have to be considered because they consume quite a bit more energy than normal fluorescent or LED bulbs. You can hang them somewhere or just put them wherever you feel comfortable. They’re likely to raise body temperature and pulse rate if they’re close enough. You should put them as close as possible to your body, but it shouldn’t feel uncomfortable. Those are some of the setups that have been used.
Shining light on the back and the neck has healing effects for the nervous systems. The lights can make you sleepy, since they reduce stress. In winter, the warmth adds to the anti-stress effect. They produce quite a bit of warmth, so some trial and error is required to find the best distance from your desk or bed. Warming the feet has an effect that’s similar to taking small amounts of thyroid hormone (T3), which reduces stress.
Melatonin, Friend or Foe?
The role of melatonin has been misunderstood by the medical field and most therapists of any kind. Melatonin increases estrogen and reduces progesterone, body temperature, fertility, and thyroid function. It likely plays a role in the shrinking of the thymus gland that happens in humans and animals in the winter. It contributes to the hibernation state in many animals, and possibly causes equivalent effects in humans; hibernation and torpor are in many ways the opposite of restful sleep.  Dr. Raymond Peat has argued that in spite of that, it can have an important positive effect by antagonizing serotonin, but no more than a 1 milligram was recommended, to induce sleep.
“Melatonin increases the concentration of free fatty acids during the night (John, et al., 1983; John and George, 1976)), so it’s interesting that one of the long-chain highly unsaturated fatty acids, DHA (docosahexaenoic acid), also increases the light sensitivity of the retina.
Melatonin lowers body temperature, causes vasoconstriction in the brain, heart, and other organs, and slows reactions. An antagonist to melatonin acts as an antidepressant, reducing “behavioral despair” resulting from stress. (Dubocovich, et al., 1990.) So, in the behavioral sense, melatonin reduces sensitivity, yet it increases the eyes’ sensitivity to light, causing them to be injured by light that would otherwise be harmless.” Raymond Peat, PhD (“Aging Eyes, Infant Eyes, and Excitable Tissues”)
Since vitamin A is required to form many protective hormones, it’s reasonable to ensure an adequate intake of it in the diet. I had an interesting experience while in Mexico and using those lights. For a while, I used them before sleeping while I was lying on my bed. I noticed they started irritating me and I felt a burning sensation on my skin if I got them too close. However, when I had some good liver, very rich in vitamin A, that stopped happening and I could use them quite close to my skin without a lot of problems.
This article is mainly meant to illustrate a practical way of using artifical light to minimize nighttime darkness-related stress. Some people have researched this subject and the effects of various wavelenghts more in-depth than me, so I recommend reading Vladimir Heiskanen’s very exhaustive article about it, and this Functional Performance System page contains a lot of useful references and quotes.
1) Use incandescent lights from sunset to bedtime, or even during the day if you live in a cloudy climate or in a poorly lit apartment.
2) Try not to live in poorly lit places or spend too much time in them during the day. Avoid fluorescent lights as much as practicable.
3) While using incandescent light, get adequate vitamin A through eggs, liver, cheese, milk, cream or supplements of it. With supplements I recommend topical application, but I don’t know of any good product at present.
4) If time and money permit, try to spend winter in a sunnier, lower-latitude location. Although I’m not a fan of it for general purposes, Wikipedia can be helpful to learn more about the climate where you live; it has some useful charts for almost any city or town.
References and recommended reads:
2. Experimental Physiology (1996), 81, 1021-1033 Printed in Great Britain NITRIC OXIDE AND PEROXYNITRITE RELEASED BY ULTRAVIOLET B-IRRADIATED HUMAN ENDOTHELIAL CELLS ARE POSSIBLY INVOLVED IN SKIN ERYTHEMA AND INFLAMMATION GEORGE DELICONSTANTINOS, VASSILIKI VILLIOTOU AND JOHN C. STAVRIDES Department ofExperimental Physiology, University ofAthens Medical School, Athens GR 11527, Greece (MANUSCRIPT RECEIVED 26 MARCH 1996, ACCEPTED 8 AUGUST 1996) SUMMARY In this study we attempted to demonstrate whether endothelial cell nitric oxide synthase (eNOS) and xanthine oxidase (XO) could be activated to release nitric oxide (NO) and peroxynitrite (ONOO-) following exposure to ultraviolet B (UVB) radiation and to define whether this lightinduced response could be involved in the pathogenesis of sunburn erythema and inflammation. Treatment of human endothelial cells with UVB (290-320 nm) radiation (up to 100 mJ/cm2) resulted in an increase of both NO and ONOO- release that was inhibited by NG-monomethylL-arginine (L-NMMA). Treatment of cell cytosol with various doses of UVB radiation (up to 20 mJ/cm2) resulted in a threefold increase of XO activity that was inhibited (approximately 90 %) by oxypurinol. In reconstitution experiments, when purified eNOS was added to purified XO, an almost fourfold increase in ONOO- production at 20 mJ/cm2 UVB radiation was observed. UVB radiation (100 mJ/cm2) decreased cell membrane fluidity, indicating changes in the physicochemical characteristics of the membranes. In in vivo experiments, when human volunteers were subjected to UVB light, a protection factor (PF) of 3.90 + 0.85 was calculated when an emulsified cream formulation containing nitro-L-arginine (L-NA; 2 %) and L-NMMA (2 %) was applied to their skin. The present studies indicate that UVB radiation acts as a potent stimulator of eNOS and XO in human endothelial cells. The cytotoxic effects of NO and ONOO- may be the main factors in the integrated response of the skin leading to vasodilatation, the first key event of erythema production and the inflammation process. INTRODUCTION Nitric oxide (NO) is produced by nitric oxide synthase (NOS) in a reaction that converts arginine and oxygen into citrulline (Moncada, Palmer & Higgs, 1991). NOS1 and NOS3 are constitutively expressed; they are Ca2+-calmodulin-dependent enzymes which are active as monomers and responsible for the transient release of minute quantities (picomoles) of NO from vascular endothelium. NOS2 is the inducible form. It is not Ca2+-calmodulin dependent and causes a sustained release of larger amounts (nanomoles) of NO from vascular endothelium, neutrophils, macrophages and microglial cells (Nathan & Xie, 1994). Although pharmacological and chemical evidence indicates that endothelium-derived relaxing factor (EDRF) is NO, other candidates, including S-nitrosocysteine, dinitrosyl-iron-cystein complex, nitroxyl anion and hydroxylamine, have been proposed to account for the vasorelaxant properties of EDRF (Feelisch, Poel, Zamora, Denssen & Moncada, 1994; Wennmalm, 1994; Arnelle & Stamler, 1995; Villiotou & Deliconstantinos, 1995). NO appears to increase vascular leakiness in several tissues (lalenti, lanaro, Moncada & DiRosa, 1992; Stefanovic-Racic, Stadler & Evans, 1993; Higenbottam, 1995). NO reacts rapidly with 02- forming the toxic peroxynitrite (ONOO-), which promotes lipid and
sulfhydryl oxidation (Beckman & Crow, 1993; Pryor & Squadrito, 1995). It has recently been
shown that the concurrent generation of NO and 02- from ONOO- modulates or promotes
lung injury by damaging surfactant protein A (Haddad, Crow, Hu, He, Beckman & Matalon,
1994). ONOG-, on the other hand, activates soluble guanylate cyclase (Deliconstantinos &
Villiotou, 1994; Deliconstantinos, Villiotou & Stavrides, 1994a).
Xanthine oxidase (XO) couples the oxidation of hypoxanthine with the reduction of oxygen,
resulting in production of the 02- anion and/or H202 (Jarasch, Bruder & Heid, 1986;
Partridge, Blumenstock & Malik, 1992). XO-induced inhibition of signal transduction in
endothelial cells is a function of H202-mediated oxidative stress and represents an early
dysfunction in the process of oxidant injury (Wesson & Elliot, 1994).
Exposure to ultraviolet (UV) radiation from sunlight causes many adverse effects, including
erythema and inflammation, premature ageing, cataract formation, immune suppression and
skin cancer. The wavelengths responsible for erythema are in the ultraviolet portion of the
spectrum, including UVB (290-320 nm) and UVA (320-400 nm) radiation (Jagger, 1985).
Recent studies from our laboratory have shown that human keratinocytes possess a NOS
which is constitutively expressed, is Ca2+-calmodulin dependent and, when it is stimulated by
UVB radiation, causes a concomitant increase in soluble guanylate cyclase (Deliconstantinos
& Villiotou, 1994; Deliconstantinos, Villiotou & Stavrides, 1995 a).
In the present studies we demonstrate that endothelial cells released NO and 02, which
react to form ONOO-. UVB radiation augmented NO and ONOO- formation in endothelial
cells by increasing both NOS and XO activities. The extent to which ONOO- damaged
endothelial cells suggests that it may be a causative factor of UVB-induced skin inflammation.
Furthermore, when human volunteers were subjected to UVB light they were considerably
protected when an emulsified cream containing NOS inhibitors was applied to their skin.
4. Exp Clin Endocrinol Diabetes. 1997;105(2):109-12.
Melatonin and serotonin regulate the release of insulin-like growth factor-I, oxytocin and progesterone by cultured human granulosa cells.
Schaeffer HJ, Sirotkin AV.
The direct influence of indoleamines on ovarian peptide hormones and growth factor secretion, in contrast to steroidogenesis, is yet to be thoroughly investigated. The aim of our in vitro experiments was to investigate the influence of melatonin and serotonin (5-hydroxy-tryptamine) (0.01-10 micrograms/ml) on the release of insulin-like growth factor-I (IGF-I), oxytocin and progesterone by cultured human granulosa cells. It was observed that both melatonin and serotonin stimulate IGF-I release. Melatonin also stimulated oxytocin output. Serotonin increased oxytocin secretion only at the highest dose (10 micrograms/ml). Both melatonin and serotonin were potent inhibitors of progesterone release. The present results suggest a possible involvement of the indoleamines melatonin and serotonin in the direct regulation of growth factor, nonapeptide and steroid hormone secretion by human ovarian cells.
5. Am J Psychiatry. 1976 Oct;133(10):1181-6.
Negative effects of melatonin on depression.
Carman JS, Post RM, Buswell R, Goodwin FK.
In order to test the efficacy of the pineal neurohumor melatonin on depression, the hormone was administered in varying doses to six moderately to severely depressed patients and two patients with Huntington’s chorea in double-blind crossover study. Melatonin exacerbated symptoms of dysphoria in these patients, as well as causing a loss of sleep and weight and a drop in oral temperature. Melatonin increased cerebrospinal fluid 5-hydroxyindoleacetic acid and calcium in three of four patients studied. The authors discuss the implications of this finding.
6. Neuroendocrinology 2001 Feb;73(2):111-22. Estrogen modulates alpha(1)/beta-adrenoceptor- induced signaling and melatonin production in female rat pinealocytes. Hernandez-Diaz FJ, Sanchez JJ, Abreu P, Lopez-Coviella I, Tabares L, Prieto L, Alonso R.