> Environmental light synchronizes the primary mammalian biological clock in the suprachiasmatic nuclei, as well as many peripheral clocks in tissues and cells, to the solar 24-hour day. Light is the strongest synchronizing agent (zeitgeber) for the circadian system, and therefore keeps most biological and psychological rhythms internally synchronized, which is important for optimum function. Circadian sleep-wake disruptions and chronic circadian misalignment, as often observed in psychiatric and neurodegenerative illness, can be treated with light therapy. The beneficial effect on circadian synchronization, sleep quality, mood, and cognitive performance depends on timing, intensity, and spectral composition of light exposure. Tailoring and optimizing indoor lighting conditions may be an approach to improve wellbeing, alertness, and cognitive performance and, in the long term, producing health benefits.
* https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3553574/
There are 61 foot notes in the above paper, so that should help you get starting going down this rabbit hole. :)
I live in Norway. While I'm below the Arctic circle, summer nights are bright. I don't need outdoor lighting to read as the sun goes juuuust below the horizon. This time of year, days are short and the light intensity never really gets all that bright. I don't have issues with any of it - and I'm an immigrant.
We thought back then that some form of "smart lighting" would be universal. This mostly hasn't happened, so the truth is that the opportunity is different than we had guessed. Today most "smart" replacement lamps are $20+, similar to several years ago, even though normal lamps are $1.
We do support a lot of integrations with f.lux on Windows, so people can use f.lux with their Hue/LIFX/yeelight/etc., but it is somewhere <2% of our users right now.
I have given the issue some thought as well. f.lux integration with Hue is great, but unfortunately not a solution for me, as I'd have to keep my windows pc running all day.
What is hard about these?
For a few dollars I can convert 120v to whatever I want.
Sell a different version to Europe
A solid driver with good filtering and good thermal characteristics is expensive. So you're left with a $15 LED bulb that sits on a shelf next to $5 bulbs, selling to customers who see nothing other than two LED bulbs where one is grossly overpriced for no reason they can comprehend
The fact that this hardware runs at 120v (or 240v in my case) makes it the barrier higher as there's now a chance that making mistakes might kill me.
Additionally, the high power levels mean that adequate cooling is needed, and as a non-expert it's hard for me to know whether I've done that correctly.
Any chance we will see a non-root flux for Android?
Btw, if you don't insist on using f.lux and have root access, take a look at cf.lumen: It allows much more precise configuration (I have it remove almost all blue in sleep mode).
During the day time all my bulbs are at 6000K and 100% brightness, at 6pm the bulbs in my bedroom/office dip to around 4500K and 50% brightness, and at 8pm to 2700K and minimum brightness (we have a toddler).
In my kitchen/living room during the day it's the same, at 8pm to 4500K at 50% brightness and at 11:30pm to 4500K at minimum brightness.
I considered having the schedule run on when the sun sets, but in my location that is 10pm in the summer and 4pm in the winter so it doesn't really work at the extremes (I have the same complaint with tooks like f.lux as well :D).
I've been looking for a hardware solution to this problem so long.
I would kill to have like a programmable dimmer knob that can progressively adjust both temperature and power set to a fixed temperature and power at start (ie: 3750k at 100%) and finish (ie: 2500k at 10%) positions then it auto-calculates the right spot in-between.
Does anyone know if I could do this on a Pi?
I wanted the lights to know what temperature and brightness to turn on to based on a schedule, but there wasn't a way for them to pull the desired state upon power-on; instead I'd have to detect power on and push a state change to the desired color temp. This meant they'd turn on at whatever last state they had on power-off, and a few seconds later (or frequently much slower) adjust to scheduled color temp.
This may have worked better had I used smart switches to turn lights on/off rather than wall switches that cut power to the bulbs, but I also had issues with the smart hub losing connection to bulbs occasionally, HA not reliably seeing power-on events for the bulbs, and HA losing connection to the hub. (Bulbs/hub were Ikea tradfri; perhaps other manufacturers' products are more reliable).
This was a couple years ago; I haven't looked into it much since - maybe it would be easier to do now.
I strongly agree that it's important to change light levels throughout the day; it's very obvious that bulbs this bright suppress my sleepiness. I should probably add this to the post's FAQ so that people don't do anything irresponsible.
I do think that some people might get a mistaken impression of how strong the evidence is when you claim that "cancer progresses much faster in constant light" without citing or caveating that this is based on one study, in rats, where the treatment shone a light on them for a full 24 hours.
Regarding only natural light, what would be the ideal latitude region for psychology year-round?
At 30°N and 30°S days swing between 10 hours to 14 hours through a year. Would it be ideal to live in between 30°N and 30°S, or would you expand/shrink the range?
ps. Any resources on geography-psychology relationships would be appreciated.
In some cases, availability of natural light (due to tree cover, weather, and position in timezone) is as important as latitude.
I would guess that some people are simply better at living at more extreme latitudes or with a weaker circadian signal. Several researchers have tried to use particular genetic markers to explain this, but I don't know a specific one that explains all of it.
This sounds fascinating. Do you have a source?
Btw, I love f.lux and have been using it since probably like 2010, possibly earlier. Its basically the first thing I install on any computer.
But as I'm refreshing my memory, winter can cut both ways. For some, it makes more darkness and more melatonin (which is thought to be protective of cancer). For others, winter results in not seeing enough light, and so melatonin amplitude goes down. And so this is associated with increased cancer.
A couple things: I don't think you necessarily need more light in the morning if you have a well-defined (artificial or real) sunset, and if you've reduced light at night to a lower level.
We add light to the morning so that we can add as much light as we want at night - the two cancel out. But I think it would be better to really try to design the evening to look different than the workday. Lights should change, and they mostly don't.
There are for sure some people with long internal clocks (DSPD/N24) who need very custom lighting schedules to have a normal schedule, but I think if we make the overall signal stronger (more day to night contrast), a lot of the differences between night owls and early birds would become smaller.
Can you elaborate ? 20k lumens doesn't seem like that much ...
I see residential interior decorating guidelines at about 20 lumens per square foot for non-intense areas like living rooms[1], etc., which implies a 1000 sf office (smallish) conservatively lit with 20k lumens.
I just put 11k lumens of background lighting in a 400sf living room and I am worried it's a bit under-lit, given 12 foot ceilings.
I think that perhaps you are talking about something different than I think you are ?
[1] As opposed to kitchens where I see 50-80 lumens per square foot recommended...
Can you point me to a reference for this? This pattern is surprising and I would like to learn more about this.
This particular claim was a hypothesis from Richard Stevens, with some experimental work that shows rapid cancer growth under constant light (in human tumors implanted in mice) by Blask (2002, 2005): http://www.nel.edu/userfiles/articlesnew/NEL230802A03.pdf
The main mechanism in the Blask work is thought to be suppression of melatonin.
However to tie it to the article : do you know of the variability between individuals of lighting effect on morale ? I know a lot of people getting depressed when winter comes, but it has 0 effect on me
(I've been meaning to try them out but haven't done so yet, so I can't vouch for the quality in detail. Their stuff is usually solidly mid-range and very good value for money, though.)
In the old Aschoff "bunker" studies where people allowed to keep the lights on as long as they wished, they concluded the human clock was 25.1 hours. We know this isn't true if you provide a proper light-dark cycle, it's much closer to 24. But I treat this old work as a cautionary tale - we can be 25.1 hour animals if we leave the lights on all the time.
When I've traveled there with foreigners who grew up at more southern latitudes with year-round "normal" day/night cycles I've sometimes had to tape black trash bags to the bedroom windows for their benefit.
What do the locals do? We simply get used to sleeping in daylight. One way of doing that is getting used to sleeping on your back with one of your arms across across your face and over your eyes (such that your elbow is between your eyes/on your forehead and the back of your palm touches or is near the opposite shoulder).
I still sleep like that out of habit at more southern latitudes out of habit, and a quick poll among some fellow Icelandic expats where I live when this came up the other day revealed that they do too.
Of course, the problem with this is that I'm totally spoiled and when I travel abroad (1), I can almost never sleep well. Hotel rooms in most countries have blackout curtains but if you're used to Spanish blinds, even those let a lot of light in from the edges. And don't get me started about LEDs...
(1) PS: Now that I come to think of it, I don't sleep well when I travel within Spain either... curiously, people's homes have blinds but hotels typically don't.
Those are only incidentally to block out light, they're mainly for thermal management. You put them down in the middle of the day to keep hot air and direct sunlight out.
A system like that is completely unsuitable in places that get snow. If you installed it on a house in Iceland it would at best freeze solid, and more likely explode as snow slush made it into the joints and froze solid. You don't even need to go outside of Spain to see that, go up to Monachil in Granada and see that no house in the area uses that system.
Of course you could install blinds like that behind double-glazed glass, but at that point you can just buy normal blackout curtains. Since you don't need it for thermal management (any amount of external heat making into the house being a luxury) there's no point in installing it on every window in the house.
So then for practical purposes you're left with only installing blackout curtains in the bedroom, but if you live that far north you're going to need to just get used to sleeping in the light anyway. What are you going to do if you go on a camping trip where you sleep in a tent and forget your blackout eye mask, just not sleep?
1. https://www.google.com/search?q=persiana+con+cajor+exterior
In most of Spain they are installed outside of the window glass, but in the north they are installed inside, so they are protected from cold and wind. As in this picture, for example (just found at random): https://www.inmoatuel.com/piso-exterior-de-90m2-reformado-a-...
But they still seal the window hole perfectly so they block light much better than blackout curtains. I suppose the problem with Monachil is that it's a cold place, but within Andalucía which is generally warm, so they don't have a tradition in the area of installing blinds inside as is the case, for example, in Galicia, where you can definitely see them even at high altitudes where snow is common.
When I go on a camping trip... indeed I just don't sleep well, I'm afraid :)
I didn't mean to suggest they weren't also used to let light in. I've spent a lot of time in houses that have these installed, letting light throughout the day while keeping the house relatively cool is a constant balancing act. I meant that without the need for the thermal management you'd go for other sorts of systems, such as internal blinds.
I.e. I'd expect that in places like A Coruña you'd use these for thermal management in the summer with the outer windows open, whereas in Iceland there's maybe 1-3 days of the year where the outside temperature is anywhere near the inside temperature.
> they concluded the human clock was 25.1 hours
You keep quoting questionable or out dated research, the 25 hours figure seems to be wrong [0]
> Early research into circadian rhythms suggested that most people preferred a day closer to 25 hours when isolated from external stimuli like daylight and timekeeping. However, this research was faulty because it failed to shield the participants from artificial light
However, we shouldn't mess with light levels like these (or even somewhat lower ones) without some limits, and the main one is some automatic timing to turn things down after it gets too late. Otherwise you will find yourself staying at work later and later each day, and it's no accident.
Our clocks don't work that well with more than about a 14-15 hour photoperiod ("day"), so spending 18 hours under 5000 lux will screw up your overall rhythms, making your internal day longer than 24 hours and reducing your sleep. This is considerably worse if you're a natural night owl - it will make you later, faster.
The myth of electric lighting is that we can live in a permanent summer and turn the wintertime into summer, but there are important seasonal questions that we should think about too. For instance, cancer progresses much faster in summer than in winter [edit: cancer progresses much faster in constant light: winter vs. summer is complicated], and the winter schedule even engages a different part of the central clock in your brain than the summer schedule does. There are some important things going on here, which we've mostly tried to remove from our environments.
Knowing how the body works and having the capability to change it really do need to evolve in parallel - I think there is way more capability than knowledge right now.