
Total darkness at night key to success of breast cancer therapy - wslh
http://www.sciencedaily.com/releases/2014/07/140725080408.htm
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herf
I made f.lux, and this is something I study a lot.

This study was done on rodents, and the problem with the reporting of it is
that rats are >100x more sensitive to this kind of light than humans are.

For white light, below about 5-10 lux, it is very hard to measure melatonin
suppression in humans. This study finds that rats have significant melatonin
suppression at 0.1 lux, which has been known since 1974 (Minneman et al) at
least.

Still, don't sleep with the TV on, and don't see bright (room) light within a
couple hours before bed, because that will actually suppress total melatonin
by a significant percentage.

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irremediable
> Still, don't sleep with the TV on, and don't see bright (room) light within
> a couple hours before bed, because that will actually suppress total
> melatonin by a significant percentage.

How do you avoid seeing bright light in the last few hours before bed?

Thank you for making f.lux, by the way. It's very cool, and I hope it gets
more thorough biomed testing soon.

~~~
actionscripted
Turn off the TV, get something like F.lux on your mobile/tablet or don't use
it and if you need light get something with low-blue output.

I searched for a long time to find a room light that avoided blue light and
you have options with dimmer stands and certain bulbs. I ended up with some
absurd-looking salt lamp that casts a soft orange light and has a dimmer (and
allegedly releases magical ions that purify or clean the air -- not buying
this last one).

~~~
mleonhard
Most products that claim to produce ions are actually making ozone, which is
very harmful to your health:
[http://www.epa.gov/iaq/pubs/ozonegen.html](http://www.epa.gov/iaq/pubs/ozonegen.html)

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Houshalter
From wikipedia:

>Production of melatonin by the pineal gland is inhibited by light to the
retina and permitted by darkness. Its onset each evening is called the dim-
light melatonin onset (DLMO).

It is principally blue light, around 460 to 480 nm, that suppresses melatonin,
proportional to the light intensity and length of exposure. Until recent
history, humans in temperate climates were exposed to few hours of (blue)
daylight in the winter; their fires gave predominantly yellow light. The
incandescent light bulb widely used in the twentieth century produced
relatively little blue light. Wearing glasses that block blue light in the
hours before bedtime may decrease melatonin loss. Kayumov et al. showed that
light containing only wavelengths greater than 530 nm does not suppress
melatonin in bright-light conditions. Use of blue-blocking goggles the last
hours before bedtime has also been advised for people who need to adjust to an
earlier bedtime, as melatonin promotes sleepiness.

When used several hours before sleep according to the phase response curve for
melatonin in humans, small amounts (0.3 mg) of melatonin shift the circadian
clock earlier, thus promoting earlier sleep onset and morning awakening.

[https://en.wikipedia.org/wiki/Melatonin#Light_dependence](https://en.wikipedia.org/wiki/Melatonin#Light_dependence)

~~~
rthomas6
So how can I know whether or not a light produces some blue light?
Alternatively, do you have any recommendations for blue-blocking goggles?

~~~
ctdonath
Probably a matter of "light temperature". Low temperatures of 2500-2700 K (aka
"warm white") are reddish, while high temperatures around 3000 K (aka
"daylight" [ETA: in advertising parlance]) are bluish. Go to a well-stocked
hardware store and they may have a display demonstrating the differences.

~~~
weddpros
3000K is still considered very warm white. Daylight is 5700k.

[http://en.wikipedia.org/wiki/Color_temperature](http://en.wikipedia.org/wiki/Color_temperature)

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tomjen3
We already knew that working nights gives a much higher breast cancer rate for
women, but is there any evidence that it is the same for other cancers?

~~~
junto
I wonder if children with leukemia are related to nightlights?

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Hytosys
The question posed here and especially the parent's comment about night light
causing cancer cannot rely on the publication as hypothetical basis. The
article merely states that the lack of melatonin conflicts with the
effectiveness of the drug tamoxifen.

~~~
junto
Indeed, so let me word that slightly better. If I had a child with leukemia
and he or she is prescribed tamoxifen, then should I avoid a night light?

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audeyisaacs
I'm not a doctor, but I would hazard a guess that a child with leukemia would
not be prescribed tamoxifen.

[http://en.wikipedia.org/wiki/Tamoxifen](http://en.wikipedia.org/wiki/Tamoxifen)

~~~
junto
After reading that I think you are probably right!

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vanderZwan
So now they relied on a lack of light to increase melatonin levels, but did
they have a control group who simply were fed/injected with melatonin? Because
if there is a difference between that group, then it becomes even more
interesting: what else does the body do in these circumstances of total
darkness?

Of course, in general we need better sleep hygiene than what we do to
ourselves now, and darkness at night would be one way. But for many it's not
easy to just switch to a regime like that.

~~~
lultimouomo
From the article summary:

tamoxifen caused a dramatic regression of tumors in animals with either high
nighttime levels of melatonin during complete darkness or those receiving
melatonin supplementation during dim light at night exposure.

~~~
raverbashing
Just as a note tamoxifen is already used for that purpose

And cancer is not sensitive to tamoxifen but rather to estrogen (which
tamoxifen is an antagonist)

[http://en.wikipedia.org/wiki/Tamoxifen](http://en.wikipedia.org/wiki/Tamoxifen)

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x0x0
wow, that's amazing if substantiated

I wonder what else we're disrupting with high levels of light. My crappy ass
landlord but a giant fucking light right outside my bedroom. The problem is if
I have blackout blinds to keep it dark at night, I won't wake up in the
morning.

~~~
jessaustin
_My crappy ass landlord but a giant fucking light..._

OMG these "security lights" are horrible! I love walking around the
countryside at night, but you have to be careful where you look if you don't
want to be completely blind the whole time. It seems like everyone in the
country has to have this giant 200W halogen bonfire burning all night. _So_
many nights I've been tempted to have a bit of fun with the rifle. "Oh did I
wake you up? I guess a turn-about is fair play."

Around here it's the electric company's fault:

[http://www.lacledeelectric.com/homesecurity.aspx](http://www.lacledeelectric.com/homesecurity.aspx)

If I had any pull with the PUC I would stop that "un-metered" crap _before_ I
stopped Ameren from raising rates to pay for a new reactor. (Because why
should our investors have to actually make an investment?) The whole
"security" aspect of these lights seems like baloney anyway. If that's the
purpose, why not get a reflector and point the damn things down at the ground?

~~~
Houshalter
They are very convenient when working outside at night. They also increase
security because there is no cover of darkness. If anything is out there you
can easily see it.

I walk outside at night all the time and it's nice to have it and certainly
not blinding. Especially if you are more than a few dozen feet away from it.
And no one has any good reason to be out there at night anyway.

Cities and towns are way worse offenders in this. Hundreds of lights at much
higher intensities. Even parking lots and empty buildings get illuminated like
its day time. It creates enough light pollution to block out the stars even.
And it's payed for by taxpayers.

~~~
jessaustin
Unless you're working outside _all night_ , please install a light switch. I
find a simple headlamp is more convenient when I have to see small details,
and it's not pointing at my eye so I retain some night vision.

The idea that lighting contributes to security is questionable. Well-lit areas
are easier to observe and navigate without calling attention to oneself. If
it's your yard and you've lived there more than a month you should be able to
walk around it blind-folded. Potential miscreants don't have that home-field
advantage, and they appreciate your leaving the lights on. While they're out
there you won't see them because you're inside watching TV. However if it were
dark and they were shining flashlights or vehicle headlights around you might
notice that. I'll allow that if there is an actual guard on attentive duty all
night, lighting will be helpful.

I know that lights make you _feel_ more secure, but that's just a reason to
have them on while you're awake.

When you're walking outside at night "all the time", even though you don't
have "any good reason to", you probably only see the ground in front of your
feet. With all that artificial light, there's no way you're seeing any
wildlife that isn't standing in the road, more than a few dozen stars, the
landscape, etc.

Cities could certainly pollute less with light. Also, those who like bright
outdoor lights on all night should move there.

Save your taxpayer angst for some other issue. The reason these lights exist
is that power is really cheap when few people are using any power, which is
generally true from bedtime to daylight. Of course the power company could be
overcharging in any particular situation, but they wouldn't have popularized
"security lights" in the first place if they hadn't had a bunch of generating
capacity to dump.

------
refurb
I would be very cautious in extrapolating these results to humans. Animal are
known to have different circadian rhythm processes. Also, cancer xenographs
(human tissue in animals) don't exactly have a great track record in terms of
generating new cancer drugs.

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Aardwolf
So many questions...

Does total darkness also exclude dim lights like LEDs? So should you avoiding
any electronics like clock radio, phone notification LED, ...?

Is having your eyes closed not enough to block out the light?

If it's about light on the skin: does lying under a blanket block it?

~~~
nitrogen
Melatonin is inhibited by light reaching the eyes. An eye mask might be
enough. Speaking with regard to sleep, not cancer, I have to block any LEDs on
things like battery chargers to sleep well. I despise the trend of putting
blue power indicators on things used at night (I'm looking at you, Air-O-
Swiss).

~~~
HNJohnC
So do I, the blue LED is the curse of the modern era. Old time red led's have
zero annoyance for me but when I walk through the living room at night and
it's all alight in blue glow from the dvr etc it annoys me on a visceral
level.

Thick black electrical tape is the best fix unfortunately.

I hope the blue light fad goes away soon.

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carlob
> however, during the 12 hour dark phase, animals were exposed to extremely
> dim light at night (melatonin levels are suppressed), roughly equivalent to
> faint light coming under a door."

If a faint light from under a door is able tu suppress melatonin, does this
mean utilities such as f.lux are completely useless?

~~~
jules
That would be surprising since ancient humans didn't sleep in total darkness
either; they got light from the moon and stars.

~~~
sanoli
I though the same thing. Anyone who's ever been camping with no other light
source other than a full moon will remember how much light (I guess is it's
pretty blueish?) the moon puts out.

But, maybe it's not too much, since our eyes are probably very night-adapted
when there's no other light source?

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joeyspn
I have sleep problems and sometimes I take melatonin (4gr) at night 30 mins
before bed. It is a harmless supplement and is easy to find and buy online or
in farmacies... it works wonders

~~~
kolev
4g or 4mg? Natural amount of secreted melatonin is much less (< 1mg), you're
overdosing with 4mg. I use 0.3mg Herbatonin, which is bioidentical natural
form of melatonin from a plant. 10-20mg is therapeutic dose.

~~~
otl1248
Any bio-availability studies on that? I assumed the high doses were because
uptake was bad / it was destroyed by stomach acid.

~~~
kolev
The whole "bioidentical hormones" thing some describe as unscientific, but
I've been taking 10mg synthetic without knowing I've overdosing (that was the
most popular OTC dose) with no effect. 0.3mg Herbatonin works pretty quickly.
Here's something I just found:
[http://www.naturalhi.com/media/custom/Newsletter%20Melatonin...](http://www.naturalhi.com/media/custom/Newsletter%20Melatonin.pdf)

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contingencies
This article makes me wonder what kind of impact my less-than-month-old
screaming baby destroying my sleeping pattern entirely has had on my system.

~~~
GrinningFool
None that hasn't been weathered by a few billion others throughout time -
you're in good company ;)

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guard-of-terra
What's the plan for people who live in the north and have a degree of polar
day? As in it's not ever getting dark.

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eik3_de
100% blinds?

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hueving
No, I'm fairly certain most of them have eyesight.

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rosser
I can see the headline now: "Scientists Say Darkness Cures Cancer"...

EDIT: Apparently, the fact that I'm mocking the kind of "science reporting"
that would turn this result into that headline wasn't _screamingly obvious_.
I'm surprised; it's a phenomenon I've seen discussed often enough here.

~~~
robin_reala
Kill Or Cure documents the Daily Mail’s cancer causatives / cures:
[http://kill-or-cure.herokuapp.com/](http://kill-or-cure.herokuapp.com/)

