Sort of OT, but this reminds me of a question I've not been able to find an answer for on blue light and sleep. (OT because the article says nothing about blue light).
One way light affects sleep is via the intrinsically photosensitive retinal ganglion cells (ipRGCs). These are a third kind of photoreceptor in our retinas, distinct from the more well known rods and cones. These are most sensitive to blue light. They signal the suprachiasmatic nucleus (SCN) in the brain with information about the amount of light they are receiving. The SCN controls circadian rhythms, and uses the changes in light as the day ends as reported by the ipRGCs to do things like to keep things that should be synchronized to the day/night cycle in sync.
Blue light in the evening can mess this up because it makes it look like it is still daylight, as far as far as the SCN can can tell from what it gets from the ipRGCs.
What I have not found anywhere is whether this is based on absolute or relative amount of blue light. Does the SCN look for blue light to fall below a certain fixed threshold, or does it do something like note the peak level of blue light during the day, and then look for the blue light to fall below a certain fraction of that?
The reason this matters is that more and more of our devices that we want to use in the evening supply blue light. We try to counter that by adding features that change the color spectrum in the evening to something with less blue. But that doesn't always work. Computers usually can do it, and often so can tablets and phones. I don't think many TVs have such a setting, though.
If the SCN works with absolute levels, fixing the devices (or wearing blue light filtering glasses) might be the only answer if you aren't able to stop using your devices in the evening.
But if it is based on relative levels, keyed off the peak daytime level...then instead of fixing all the devices it might be possible to address the problem by greatly boosting blue levels in the middle of the day, so that your evening device levels will be far enough down from the peak to not affect anything.
IIRC from reading papers, there seems to be a dose-response effect, both w.r.t intensity and match to peak sensitive wavelength (~465nm). Even green light has some effect.
Avoiding blue light at night after you go to sleep is definitely an under-appreciated problem, especially for folks that stay up late. If you have a habit of going to bed at 2:30am, and the sun rises at 5:30am and comes in your window, you're getting blue light during your circadian night (enough light can make it in through your eyelids to be a problem) -- this may screw up your sleep schedule.
Anecdotally, I know the amount of light that comes in between the window sill and the curtain can throw off my sleep schedule - I tend to feel most alert around 1am, so I'm a late sleeper, and when the sun rises early (~4:30am in summer around here) I tend to feel unrested or I'm woken after only an hour or two's sleep (and can't get back to sleep even after getting rid of the light). Putting the curtain up on the window sill to block the light completely gets rid of that effect.
Oddly artificial light (even with bulbs on the blue-end of the spectrum) tends not to do the same -- if I'm woken for other reasons and use artificial lights and displays then try to get back to sleep, or leave lights on in the room, it's usually not an issue. No idea if that's some sort of dose-response effect or a reaction to the sun cycling rather than being constant (or even placebo potentially).
No. Not at all - you do want blue light in the day, that too helps keep your clock regular. (A constant morning time is crucial.) But all that won't compensate for blue light stretching into the evening.
Even way more red light at the same time as some blue light in the evening, while it helps reduce the effect of the blue, isn't fully effective.
I haven't done any rigorous science, but having zero screen time at least 2hrs before sleep and having warm orange lighting definitely allows me to have long uninterrupted sleep. Heavy screen usage before bedtime has the same effect as drinking on my sleep patterns.
I grew up sleeping in pitch black darkness, and having lived now for a while in the Nordics, where summer nights are light and curtains are mediocre at best, I can share that feeling.
I wonder if the higher rates of depression here may have something to do with this (interestingly, I remember reading somewhere that suicides in the Nordics peak in Springtime).
Second that! Curtains in Copenhagen don't blind, they blur. I think part of the reason for the spike in suicide in springtime is the hope that "things-will-be-better-in-the-light" being broken. The third monday of January has a spike in suicide as well, on account of the New Year not bring the prosperity that the excitement of december had you believe. Psychiatrists supposedly call that day blue monday.
I've lived in Norway (40 km south of Oslo for the last 32 years, generally with only light curtains. Not noticed any tendency to depression or difficulty sleeping in myself or my family.
Mind you, most hotels here that expect foreign guests have blackout blinds or at least very heavy curtains,
My first Summer in Finland, I was renting an apartment with crappy curtains. I was dead tired through May, until I broke down and duct-taped large trash bags to the windows. The difference in sleep quality was nothing short of amazing.
I have blackout curtains nowadays, and I've also gotten used to the light somewhat, but I still miss proper rolling curtains that completely shut the light out.
They are fairly common throughout most of Central Europe. I stayed in apartment a few years ago that had electric shutters; it felt like I was living on a space ship.
The same in Denmark, but in my experience people still have curtains in the bedroom. It would be difficult to sleep (especially for children) in the summer without them.
The type shown in the video is pretty common in Germany and besides its ability to make a room pitch black it also provides a decent protection against burglary.
Many, if not most of these shutters are certified for resistance class RC2 according to DIN EN 1627.
The title of the video is wrong, by the way.
It is not Rouladen, which would be a dish of filled rolled meat, but Rollladen. Rollladen is literally rolling shutter and it is really written with three l in a row.
In Italy they're "tapparelle", and I think they're a fantastic thing to have for your house. With even mediocre ones you can get a room really dark even if it's pretty light outside.
The first result on Google search points to Ikea Marjun curtains, I bought those when I lived in Berlin and I guarantee you that it was impossible to get my bedroom really dark.
On the other hand with proper outdoor shutters or roller blinds[0] you can easily get a room pitch-black.
Should we assume that the light itself is causing the depression? Or should we assume that the light leads to poor sleep, and then the poor sleep is what triggers the depression?
I could imagine that being chronically deprived of quality sleep is different than skipping an entire circadian cycle once per week.
Edit: I recently made the mistake (for a few months) of taking my medication before bed, rather than in the morning. This included vitamin D. Guess what happens when the body gets a dose of vitamin D at night? No quality sleep for you! So I certainly sympathize with the quest for quality sleep.
Good question, however a rush of steroids for one day incidentally boosting mood isn't inconsistent - it's just the body treating that day as something of an emergency situation. A swallow doesn't make a summer.
I've spent prolonged periods living away from artificial light. In such situations, the lunar cycle has a profound effect on your psychology and sociology. New moons are quiet times, and wildest parties happen at full moon. Makes me think that "lunatic" is probably a very, very, very ancient concept.
>I just wonder about how actually natural a pitch black sleep is.
"Pitch black" is another thing entirely, but the moon is much dimmer than the light levels this study reports as causing depression (5 lux). And it's pretty dim (equivalent to stray light from a streetlamp).
>The intensity of moonlight varies greatly depending on its phase, but even the full Moon typically provides only about 0.05–0.1 lux illumination
Please consider including links to local crisis helplines e.g. [1] and [2]. Doubtless some people in the midst of a crisis will discover this resource, and it is really important that they are aware there is immediate help available. [3]
On the other hand you may turn away depressed people who are not in a crisis because they don't want to be associated with the idea of suicide when their main problem is they have no will or energy to do anything ever. You might end up hurting these people by constantly mentioning suicide whenever they finally get the guts to learn about their depression. "Oh, you depressed? Here, read about suicide! Let me scare you back into your hole!"
-a once depressed person whose recovery was delayed by the association described
I added a real blackout curtain to my room and really noticed a difference in the quality of my sleep and my general mood. It was designed to really black out all light... https://www.amazon.com/gp/product/B003ZJ88DY/
What we ought to have is a blackout shade that will automatically roll down at night and back up in the morning, when we want sunlight to start waking us up.
Look for motorized roller curtain. I have those in two bedrooms. They are actually very convenient, even though I just have the remote control and not any automation. DIY persons can also find instructions for getting the shades from IKEA and motors from Ebay.
Mine are using motors/control from Somfy. Those have at least worked flawlessly for several years.
For the roller curtains there are also models which have "things" on the sides where the curtain slides in. This blocks the light that would otherwise shine in from there. If this is not an option, should look for curtain which is dark from the outside. This should also help a little bit.
I use a combination of blackout shades, Philips hue lights, and the Sleep cycle app on my phone. It starts the lights very dim and red at the beginning of a 20 minute wake up window, slowly brightens them, and then rings the alarm whenever I start rolling over. It is a little complicated, but it has worked well for a few years now.
Those unfortunately don't fit all window sizes. If you need custom sizes, a company called BlackoutEZ makes the same product but let's you pick the size.
I can attest to these blackout covers making daytime sleep not hell. I don't even need zolpidem to fall asleep anymore.
> Our study has several potential limitations. First, participants were not randomly selected,
possibly leading to selection bias. However, the parameters of BMI and estimated glomerular
filtration rate were similar to corresponding national data in Japan and the follow-up rate was sufficiently high.
> Second, bedroom light intensity was measured without eye-level light meters, and sleep/awake status was measured only over 2 days.
Skimming the original study, it talks about subjects opening and closing their eyes, so I would very much assume that it's entirely related to seeing light (and not about absorbing light through the face or body).
If you get a sleep mask, be sure to look for one designed to not put pressure on your eyes, which are not hard to find if you seek it out. The cheap ones you get at pharmacies and dollar stores put direct pressure on the eyeballs and it's a wonder that anyone can tolerate them and are perhaps even harmful.
I just discovered sleep masks, and they've changed my life.
I bought some on Amazon and got a few different kinds (from the same listing, which is frustrating). All of them have a dome that bulges out over each eye. The most comfortable one I have looks like an eye bra, but unfortunately I can't find a place to order more.
Uhhh, are you sure about that? My ten dollar sleep mask from walgreen doesn't touch my eyes, I don't think it even touches my lashes. Meanwhile every mask I've tried buying online has fit terribly.
I think he's talking about literal dollar priced masks or giveaway sleep masks which are usually just a tiny piece of fabric around something more solid, which attaches to you by means of an elastic band; the band however resists falling/slipping by pushing on your eyeballs.
It sounds like your mask is a bit better, and probably more expensive that the parent means. I've gotten such cheap masks as giveaways and the few I tried were indeed unbearable for sleeping as it felt like someone was crushing my face.
I've been delighted with "Mack's shut-eye shade premium sleep mask" for years. I've only needed to replace my original once.
I started using these when I was a traveling consultant, and now use it only for travel, when taking an afternoon nap, or sleeping in (usually due to illness).
It's very comfortable. The nose bridge is padded. There are two straps, from the top and bottom of the sides, so you don't have a strap routing over the ear. I find it lets in the least amount of light of the masks I've tried precisely because of the comfort features. I don't have to try to arrange the mask in some contorted way to get comfort, so it can sit as intended and block light.
The best I've found isn't sold as a sleep mask, but a "heat massage" mask with beads in it. I never heat it, I only use it as a sleep mask, the beads provide a wonderful, and comfortable, light seal.
Weirdly, we now know that even the brain has light receptors. (The skull is very transparent when wet with CSF.) Night nurses know that a flashlight hitting a sleeping patients leg in darkness causes a contraction.
Sleep masks help a lot - but they aren't a full solution.
I currently sleep in a room with zero natural light.
I can't tell you whether this makes me more or less likely to be depressed (I think it pales in comparison to other things in my life), however I do always keep a low light on -- without this, it would be very difficult to find my bearings when I wake up.
Also, it is extremely difficult to wake up when it's completely pitch-black.
There are a bunch of results for "light at night" on Google Scholar and Pubmed, but I'm not sure of specific references. This particular study (a manuscript is available on sci-hub[0]) does not have a discussion of this topic (other stuff that could come with the light) at all and two reviews I searched for "noise" and "sound" did not seem to have a discussion either. I'm sure some of the many studies over the years have at least actively changed the lighting and measured melatonin, but it is sloppy to not even discuss the topic.
In the case of this study, a figure at the end of the manuscript shows that most of the light exposure (averaged) happens in the hour after bed and hour before getting up, so that seems like a big clue that it isn't just a case of light at night (ideally they would divide light exposure into three segments and look at each). Also, the study started with people not showing depressive symptoms but it didn't consider if light exposure had changed and the study seems on the small (863 people) and short (median 2 year follow up) side if light (and whatever else) exposure had not changed. For that matter, it sounds like they only measured light exposure and sleep for two days and assume that is representative of the whole period.
It sounds like the depression scale[1] was given at the beginning and end of the study and looking at number or duration of episodes could have a different result. Also, it isn't clear that depressive symptoms here necessarily correspond with depression or if they are signs of a sleep disorder.
All in all, this isn't a good study to look at individually.
I am not going to be able to dig into the bibliography mentioned. I have been skimming titles and I am not swayed.
I used to be on a health list where abstracts were frequently posted. I stopped bothering to read the abstracts after speaking with a man with a PhD in chemistry who told me the abstracts frequently claim the opposite of the study.
A relative of mine works at the CDC and has had cancer multiple times. They used to bitch at me about the lack of good cancer studies. The detail I recall them lamenting was that basically you got dozens of variations on whatever the latest funding craze was because researchers could get money for that and maybe one out of a hundred studies was actually proposing a new idea, if that much.
I have read bad studies. I have participated in bad studies. I have been on health lists where people were asking for tips on how to qualify for studies as a means to get free treatment. It looked to me like a form of gaming the system in a way that would skew research results. I don't think they were up to anything nefarious. They just had serious health problems and we're desperate for help. But if you are getting tips for how to get into the study that you don't currently qualify for, I cannot help but think that will skew the study results.
I am generally a skeptical person anyway. But I am very leery of this kind of research.
Slightly off-topic: I've noticed if I work all night (e.g. yesterday writing a paper proposal for a conference), and I manage to stay up all the way until dawn, I literally get euphoria once Sun glances through windows. I can be super tired, but it shots my mood up considerably.
Actually, they didn't touch the lights at all, they only measured the lights that people already were exposed to. They write that "an interventional method, such as a randomized controlled trial using a LAN exposure, is not possible because of ethical concerns".
If "ethical concerns" prevent even this mild and useful intervention, ethics has turned into anti-science paranoia. There has got to be a middle ground between mad science and today's bureaucratic IRB busybodies.
It seems like giving half the people blackout curtains and then monitoring depression levels would be perfectly ethical, since it's expected to improve their life, if anything.
There are ways to set it up with an alternate/sham treatment for the control group (maybe some nice pictures to hang on the wall--something equally decorative but not light-blocking). It's not perfect because there's no way to make it fully blinded, but the results would still be a substantial improvement over the existing observational study discussed in the article here.
> Actually, they didn't touch the lights at all, they only measured the lights that people already were exposed to.
But isn't it a flaw of the study? It only shows correlation without causality. What if being exposed to light is correlated to some other factor that is responsible for increased depression? In this case, decreasing the amount of light won't decrease depression.
It’s unethical to do X when X is expected to harm the study subjects. Exceptions are sometimes made for interventions with terminally ill patients, but in general studies that are expected to harm subjects are not approved by ethics boards.
They could reasonably do an intervention study that only reduces bedroom light to confirm if that corrects depression on subjects.
> They write that "an interventional method, such as a randomized controlled trial using a LAN exposure, is not possible because of ethical concerns".
They're wrong about that. The intervention group could be advising people to avoid light, and having someone come to their house and install better shades and put tape on LEDs.
I think a lot of studies like this are just wrong. When I was a kid, I couldn't sleep without a light on because I'd get depressed. So later on in life if I didn't remember that, I'd think that I just had a light on and now I'm depressed. I think depressed people like a little light.
Much like they say red meat causes cancer, I don't think it's the red meat. I think it's how it's cooked. Red meat is usually barbecued and that char is what could be causing the cancer.
I kind of agree about the light. Everyone I know that needs some light on during the night needs it because of some problem. Either the person is afraid of being in total dark, which is a sign of anxiety and is associated with depression, or have some other problem.
I don't like sleeping with the lights on, but it became a necessity because I have frequent sleep terrors where I wake up confused in the middle of my room. A light helps me understand what's happening and where I am faster, and I don't collide into things as much. Sleep terrors are associated with some mental problems, so there would be a correlation between mental problems and the fact that people have the lights on too (considering I'm not the only one who does that), but both things are not causally connected.
Maybe a bit OT, but my understanding of meat causing cancer is that if you don’t eat enough fiber to clear out the intestinal sludge then it harbors the conditions for cancerous cells to come about. I need to follow up on that more. Even more OT, but it’s irrelevant now as I took a break from meat a year ago after my Plated boxes piled up over the holidays and I couldn’t eat it fast enough . I noticed how supple my body was after a while and got to questioning the food industry and finding too many answers related to my health that I didn’t like. Eating enough seasonal fruit is beneficial in any case, the water clears out toxins. Good point about meat char, seems minimal compared to gunk buildup from an overall health perspective. I dunno if we really thrive as meat eaters anyway, given my health then and now.
>So later on in life if I didn't remember that, I'd think that I just had a light on and now I'm depressed.
What? Anyway, this study has strict definitions of what "depression" is, and I doubt whatever you felt as a child would qualify.
>Much like they say red meat causes cancer, I don't think it's the red meat. I think it's how it's cooked. Red meat is usually barbecued and that char is what could be causing the cancer.
They say eating red meat may cause cancer. Even if your guess is true, they would still be right as red meat is often barbecued. And as a larger point, thinking something like this is true doesn't matter until you get evidence for it.
I still think you're confusing whatever feelings you felt with clinical depression.
>They would be right about red meat but the point would be lost if people begin switching to bbqing chicken and still get cancer.
The study was showing a link they found, they weren't giving a diet recommendation. But, it would only be lost if your guess was correct and everybody that made the switch barbecued as much chicken as they did beef. Otherwise, fewer people would develop cancer than if the scientific study had not been published.
What I don't like are the "solutions" they propose: noise? use earplugs, light? use curtains. Well I will not be able to sleep if I have something in my ears and if you pull the curtains then you can no longer wake up naturally with the Sun. How about changing your lifestyle so that you can have silence and dark during the night and light in the morning without any "devices". You might have to quit your job :)
1. I've never done this. Not as a child, not as a teen, and not as an adult. I'm nearly 40. I can get myself to wake between 9 and 10 with an alarm, 11 or noon without.
2. I live too far north for this to be reasonable. December days are around 4.5 hours long. Summer nights don't actually get dark here. The sun goes down and stays just below the horizon, so there is a few hours of twilight. You can read outside if the sky is clear.
He didn't say that other people should change their jobs for him. He said they should change their jobs instead of having to sleep with earplugs or curtains. But I think he fails to realise that many people live in very different environments to him.
I doubt that you wake up naturally with the Sun. Where I live the difference between Winter sunrise and Summer sunrise is about 6 hours. Most people keep more regular hours throughout the year.
Me too. I always tend to wake up the exact same time (right down to the minute) every single morning, no matter how early or late I sleep. And I don’t set an alarm clock and use blackout curtain.
According to [1], the difference between between winter and summer where I live is rather severe -- varying from 12 hours night and 7.5 hours daylight in winter to zero hours of night (I've read outside with no artificial light in those conditions - there's still quite a lot of light) and 17 hours of daylight in summer. Sunrise varies from 4:30am to 8:30am. I'm not sure most lifestyles can manage that sort of swing through the year.
> those exposed to more than five “lux” of light each night had higher rates of depression
Light can be measured, depression cannot. It barely even has a definition, let alone quantifiable rate. I'd sooner believe that auto-playing videos had a stronger link to depression than lux.
Random theory... Maybe depressed people are highly sensitive to the world's problems/suffering both in immediate and wider environment, their antennae picks up this instability that manifests as internal trauma, anxiety etc. Someone should do an experiment to see if isolation for a few weeks influences depression rate; avoidance of all news, no phone, no internet, no people. Get ready for "Study finds extreme boredom effective anti-depressant".
One way light affects sleep is via the intrinsically photosensitive retinal ganglion cells (ipRGCs). These are a third kind of photoreceptor in our retinas, distinct from the more well known rods and cones. These are most sensitive to blue light. They signal the suprachiasmatic nucleus (SCN) in the brain with information about the amount of light they are receiving. The SCN controls circadian rhythms, and uses the changes in light as the day ends as reported by the ipRGCs to do things like to keep things that should be synchronized to the day/night cycle in sync.
Blue light in the evening can mess this up because it makes it look like it is still daylight, as far as far as the SCN can can tell from what it gets from the ipRGCs.
What I have not found anywhere is whether this is based on absolute or relative amount of blue light. Does the SCN look for blue light to fall below a certain fixed threshold, or does it do something like note the peak level of blue light during the day, and then look for the blue light to fall below a certain fraction of that?
The reason this matters is that more and more of our devices that we want to use in the evening supply blue light. We try to counter that by adding features that change the color spectrum in the evening to something with less blue. But that doesn't always work. Computers usually can do it, and often so can tablets and phones. I don't think many TVs have such a setting, though.
If the SCN works with absolute levels, fixing the devices (or wearing blue light filtering glasses) might be the only answer if you aren't able to stop using your devices in the evening.
But if it is based on relative levels, keyed off the peak daytime level...then instead of fixing all the devices it might be possible to address the problem by greatly boosting blue levels in the middle of the day, so that your evening device levels will be far enough down from the peak to not affect anything.