
Optimal Light Exposure for Rapidly Correcting Circadian Misalignment - timr
http://www.ploscompbiol.org/article/info%3Adoi%2F10.1371%2Fjournal.pcbi.1003523
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realitygrill
Anyone with sleep problems owes it to themselves to read _Chronotherapy_ by
Terman and McMahan (2012).

Basically, for manipulating your circadian rhythm, light therapy is
recommended as the first line of treatment (possibly supplemented with low-
dose melatonin). The timing and intensity of light relative to when your
internal clock thinks it is in the day determines the amount of slowing or
lengthening of your cycle. So bright light during when your body thinks it is
'morning' will slow down the cycle, and bright light at 'night' will lengthen
it. That's why many people use f.lux. But how much, how long?

Your cycle's natural free-running cycle length (without zeitgebers, or cues,
to entrain it) appears to be determined by genetic factors. This is hard to
measure without doing some tracking and, ideally, actually free-running.
Pretty inconvenient.

This paper, which I look forward to reading in-depth, claims to have figured
out optimal ways [took another look: general principles] of calculating the
correct exposure and absence of light to allow for rapid recovery from jet
lag. If true, it will probably make all light therapy much easier to do and
calculate.

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a8da6b0c91d
I'd be careful with melatonin. It appears to act like a stress hormone and has
a bunch of significant effects. It boosts estrogen and lowers metabolism.

~~~
realitygrill
Light therapy is the main thing (seems daylight simulation and negative ions
may also work, but this is less researched). The melatonin option is indicated
at the level of micrograms, and as far as I know is quite safe. I'm mostly
drawing from gwern's analysis and the opinions of several doctors, though, for
the safety profile:
[http://www.gwern.net/Melatonin](http://www.gwern.net/Melatonin)

Care to share some references? It would be useful to add to the page above.

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a8da6b0c91d
There's a bunch of easily found stuff on animal experiments where it shrinks
gonads and brains. It clearly turns off fertility in animals. It's well
understood as the "winter hibernation" hormone. It's not the "good circadian
rhythm night of deep sleep" hormone like people seem to think. It rises to
adapt the body to the stress of darkness of winter, it doesn't rise to make
you get better rest. It makes the retina more sensitive to light and lightens
skin. It's high in seasonally depressed people. Taking a sunny vacation lowers
it, and makes you feel better.

Nobody has a melatonin deficiency; you don't need melatonin levels to get
restful sleep. If stress hormone levels are low you can fall asleep under
bright lights with no melatonin.

I can't say taking 5mg every now and then would be harmful to humans, but when
you understand melatonin's essential role as the winter hibernation hormone,
and consider the animal experiments, I think you might want to prefer other
means to get to sleep. Personally, I find diphenhydramine (benadryl) pretty
good for occasional help nodding off. And that's very clearly safe for
occasional use.

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quotient
I couldn't find any statements backing up your claim that Melatonin shrinks
brains; in fact, I found allegations to the opposite: Melatonin appears to
have neuroprotective properties.[0] I suggest you cite your sources,
especially when making sweeping claims like "it's well understood as...",
"easily found stuff", etc.

[0] [http://www.lef.org/magazine/mag2013/sep2013_Melatonin-The-
Br...](http://www.lef.org/magazine/mag2013/sep2013_Melatonin-The-Brain-
Hormone_01.htm)

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Eliezer
I am a tad perturbed that a quick skim didn't present to my eyes any
statements along the lines of "But we never tried it, at all, so take it with
a grain of salt."

Either that or I somehow completely missed the table showing the effect of the
schedule on subjects vs. controls, or any other sort of experimental
confirmation whatsoever.

To be clear I don't object to the analysis or its methods, I object that it's
not being clearly confessed to be an analysis in bold letters.

~~~
monochr
This just a numerical simulation on two (simple) models of the human sleep
cycle system that tries to find a more efficient way of shifting the cycle of
those methods.

I've only spend 40 minutes reading the paper so far and only have a
superficial understanding of it, but to me it looks like they are using a
somewhat oscillator like model and looking to introduce a phase shift in the
response by driving it with different input functions.

There is no experimental verification whatsoever. This is why this was in the
computational biology section of plosone.

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ioddly
This is quite interesting. As someone who has delayed sleep phase syndrome, I
wish I'd known about the mathematical models they mention a few years ago. I
had to figure out my own light therapy schedule by trial and error.

The next step, of course, is to actually try it out. It appears there's an iOS
app based on this:
[http://entrain.math.lsa.umich.edu/](http://entrain.math.lsa.umich.edu/)

~~~
a8da6b0c91d
I think the important thing is to get as much natural daylight exposure as
possible. Sunlight lowers stress hormones, lowers depression, increases
metabolism, and so forth. So I'm skeptical about "apps" and algorithms that
are about micromanaging how much dim artificial light you get. The much more
important thing is getting out in the midday sun for an hour or more every
day.

~~~
LnxPrgr3
I'm a definite fan of getting mid-day sun, but my understanding is while it'll
help maintain sleep rhythm, it won't correct it if it's already out of whack.

For that, I'd suggest getting some sun (or failing that, some light therapy
lamp exposure—a special-purpose lamp that puts out a blinding amount of light)
first thing when you wake up. Of course, you could optimize further too, like
this paper suggests.

Source is admittedly Wikipedia:
[http://en.wikipedia.org/wiki/Delayed_sleep_phase_disorder#Ma...](http://en.wikipedia.org/wiki/Delayed_sleep_phase_disorder#Management),
and [http://en.wikipedia.org/wiki/File:PRC-
Light%2BMel.png](http://en.wikipedia.org/wiki/File:PRC-Light%2BMel.png) in
particular.

~~~
cpncrunch
I have occasional problems with sleep disruption in the winter months (October
to March, 49 degrees latitude). The problem is that natural sunlight simply
isn't strong enough to reset your body clock.

When it happens I take a melatonin at night, and it seems to reset my sleep
cycle and gives me a really good night's sleep. I don't normally take it more
than once a week at most, just in case there are any negative effects. The
delayed release tablets seem to work best (Jamieson, I believe it is), as they
slowly release the melatonin over a period of 8 hours.

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1gn1t10n
In case the main link is not working as it did for me, I spotted an alternate
source for the publication [1].

[1]
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983044/pdf/pcbi...](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983044/pdf/pcbi.1003523.pdf)

