

Quantified Self: investigating Vitamin D & sleep with a Zeo - gwern
http://www.gwern.net/Zeo#vitamin-d

======
ericabiz
It _is_ worth it to point out that Vitamin D has been shown to prevent
colds...but the "recommended" dose unfortunately still leaves people
deficient.

A nutritionist recommended I take at least 5000IU a day (with regular blood
tests to confirm I wasn't going over the limit.) My blood test level started
out at 18 ( _extremely_ low, despite the fact that I lived in San Diego at the
time) and is now a more respectable mid-50s.

Most Americans are chronically Vitamin D-deficient (sources:
[http://www.scientificamerican.com/article.cfm?id=vitamin-
d-d...](http://www.scientificamerican.com/article.cfm?id=vitamin-d-deficiency-
united-states) and [http://planetgreen.discovery.com/food-health/vitamin-d-
defic...](http://planetgreen.discovery.com/food-health/vitamin-d-deficiency-
putting-americans-at-risk-for-a-host-of-ailments.html)) and at this point,
it's pretty much safe to assume that you're not getting enough of it and to
consider taking a 2000-5000IU daily supplement.

Anecdotally, I can say it's made such a huge difference in me getting less
sick on a regular basis (and is SO cheap) that I've been recommending it to
pretty much everyone I know.

I've also become a huge fan of NOT wearing sunscreen, especially if you're
going to be out in the sun for less than an hour. With proper Vitamin D
levels, you actually burn _less._ Try it for yourself and see--it's been a
massive difference in my life.

Vitamin D I use (Only $8 for 4 month's worth! Disclaimer--Amazon affiliate
link, but it is actually what I use) <http://amzn.to/zJYS1X>

~~~
dhbanes
Have you considered sublingual vitamin D? Just curious since I'd always
thought it to be the preferred form but see more people caps.

~~~
ericabiz
I have, but the ones I got tended to crumble into tiny pieces before I could
even get them in my mouth, so I went back to the capsules.

~~~
dhbanes
I currently use liquid sublingual but wonder about shelf life. Going to give
the caps a try.

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jrockway
I've pretty much given up on experiments like this. There are just too many
variables to control for; maybe you're sleeping poorly because you're stressed
out rather than because of the Vitamin D pill you happened to take today. I've
used a Zeo and can draw conclusions between what the chart shows and how I
feel, but I haven't been able to do anything to control what the chart looks
like.

Honestly, the deepest effect I've been able to determine through personal
experimentation is that coffee contains some sort of stimulant. Anything else
is too subtle for me to be confident about.

~~~
gwern
> There are just too many variables to control for; maybe you're sleeping
> poorly because you're stressed out rather than because of the Vitamin D pill
> you happened to take today.

The answer to variables and problems is better setups (more blinding, more
randomization, more data), and not counsels of despair. I agree that there's a
lot of variability in sleep scores, which is why I run things for as long as I
have patience for (in this case, ~43 days; with melatonin, I could run for
many months because it wasn't hurting my sleep but helping it).

------
jerf
gwern, after reading the rest of that page, especially the melatonin section,
it looks like your next sleep experiment should be a double-blind experiment
on getting rid of the cat. I'm not sure how you'd double-blind that, but
extrapolating linearly from your description of how you double-blinded the
Vitamin D capsules I would imagine it looks something like having a housemate
randomly stuff the cat into one of two bags and you randomly opening precisely
one each night via some sort of complicated-but-scientific mechanical
contraption. (Perhaps based on the random decay of a radioactive atom for some
extra classical flavor.) I would definitely expect some sort of statistically
significant effects on sleep to arise from such an experimental setup. In
fact, it would probably be so statistically significant that even the others
sharing your house would experience statistically significant effects on their
sleep, and that's a whole heaping helping of significance.

~~~
gwern
> I would imagine it looks something like having a housemate randomly stuff
> the cat into one of two bags and you randomly opening precisely one each
> night via some sort of complicated-but-scientific mechanical contraption.

I dasn't - I'd be accused of being a sociopathic animal abuser (again). On the
other hand, there must be _some_ way to rig the door to open at, say, 1 AM
with 1:1 odds. Hm...

------
ot
This guy is either a genius or he's completely crazy:
<http://www.gwern.net/Nootropics>

~~~
gwern
I am most definitely not a genius (<http://www.gwern.net/Links#iq>), so I
guess I am just crazy. Oh well - hopefully I'm the entertaining kind of crazy
and not the unpleasant kind.

------
Gatsky
I'm not a statistics expert, but I would argue that using a t-test is not
appropriate in this setting where you are alternating melatonin and non-
melatonin days. There are two potential reasons for this:

1\. One night's sleep is likely to influence the next night, and this cannot
really be controlled for in the current design.

2\. I think there is 'information' or statistical power available in the
scenario where you sleep poorly on a melatonin off day after sleeping well on
a melatonin on day, because this supports the hypothesis that melatonin helps
sleep rather than the null. The key to making n=1 experiments more relevant is
harnessing this fact statistically. Not sure how one would do this however.

~~~
gwern
> I'm not a statistics expert, but I would argue that using a t-test is not
> appropriate in this setting where you are alternating melatonin and non-
> melatonin days.

I'm not an expert either; I just do the best I can, and using a t-test is
better than not using any test, y'know?

> 1\. One night's sleep is likely to influence the next night, and this cannot
> really be controlled for in the current design.

Seth Roberts actually said something like that about my vitamin D setup,
arguing there could be spillover effects to the next day, which is why I spent
any time looking at the 'lagged nights' to see if there was any odd behavior
in the following nights. His suggestion was to randomize blocks of nights or
even weeks, rather than individual days. Of course, it was a bit late to start
over and I didn't really feel like running _another_ experiment...

------
thisisnotmyname
He really needs a positive control, i.e. something he knows for sure improves
his sleep in order to quantify the effect. Say his data shows a small effect,
and it is even statistically significant. He still won't have learned anything
without having some reference for the magnitude of the change.

~~~
gwern
> He still won't have learned anything without having some reference for the
> magnitude of the change.

I don't think that's true. This is what the concept of 'effect size'
(<http://en.wikipedia.org/wiki/Effect_size>) was developed for, quantifying
how big a divergence we're talking about. I didn't calculate it here because I
literally just starting using R a few days ago and I don't know how.

A quick and dirty way is to look at the difference in the 2 means and compare
it to what is the 'normal range' (intuitively something like a standard
deviation or two), which in this case, my ZQ ranges normally from the mid-80s
to the very low 100s (a range of ~20 points), and the difference in ZQ means
is 4 points. So that's 1/5 the normal variability - that's nothing to sneeze
at! (By a strange coincidence, this is almost the same sort of numbers as for
grades in class, so we could analogize: not taking vitamin D at night would
improve my sleep grades by one letter. When I was in school, I would not have
turned my nose up at such an intervention.)

So, your comment is wrong as stated, I think. But as it happens, I _do_ have
something which could serve as your 'positive control': my previous (unblinded
non-randomized) experiment with melatonin over half a year or so, which found
a shift in mean ZQs of ~8 points. I was really impressed with melatonin when I
first started (as have many people been), so to find vitamin D is half as
hurtful as melatonin was helpful... I had no plans to take vitamin D in the
evening before, but I sure as heck don't now!

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derekja
nice! It's nothing more that an N-1 experiment, but I've really enjoyed using
the Zeo to try and quantify what my sleep is doing.

A couple years ago I wrote a little lucid dreaming app for the zeo you might
be interested in.

[http://blog.myzeo.com/forum/zeo-raw-data-library/lucid-
dream...](http://blog.myzeo.com/forum/zeo-raw-data-library/lucid-dreaming-
application/)

~~~
derekja
oh, also, in terms of replacing the pads. Every couple months I put a little
dab of EEG conductive paste on the pads and they seem to last forever. I have
needed to change the headband, though.

~~~
gwern
Really, that's a very interesting strategy. So would that paste be something
like [http://www.amazon.com/Parker-Labs-Tensive-Conductive-
Adhesiv...](http://www.amazon.com/Parker-Labs-Tensive-Conductive-
Adhesive/dp/B0011YY9YM/) ?

(Also, I do plan to look into programs that work with the serial cable - more
for meditation than lucid dreaming - but I haven't bought the cables and
connectors yet.)

~~~
derekja
yup, except that you don't actually want the adhesive. I use Ten20 conductive
gel. [http://www.amazon.com/Ten20-EEG-Conductive-Paste-
Tube/dp/B00...](http://www.amazon.com/Ten20-EEG-Conductive-Paste-
Tube/dp/B002R16OUK)

------
rbarooah
Have you noticed Seth Robert's more recent postings about time of day being
critical to Vitamin-D effect? It sounds as though you were taking it just
before bed - which is the exact opposite of what he now recommends.

~~~
gwern
As I say in the first sentence, those anecdotes were why I started in the
first place.

~~~
rbarooah
You say: "Seth Roberts has speculated that vitamin D, despite its myriads of
other benefits, may harm sleep based on some anecdotes (with 2 null results)"

My point is that he's collected a lot more anecdotes since then, and there
seems to be some indication that Vitamin-D _helps_ sleep when taken at sunrise
rather than at night. I was curious about why you didn't mention this. I'm
guessing that the posting just pre-dates his newer observations.

~~~
gwern
I got tired of collecting anecdotes; after a little bit, one more anecdote
'well I kind of sort of felt better although you know I didn't collect any
kind of data whatsoever' is just pointless to link to. Sleep is variable, you
can see any pattern you want to in a few days, especially with a dab of
selection bias. (If I had stopped after 10 days, the means would have looked
more impressive; but the p-values tell the truth.)

~~~
rbarooah
Have you considered taking Vitamin-D at sunrise as Seth suggests?

~~~
khafra
Gwern wrote in his experimental design that he took Vitamin D supplements in
the mornings, when he hadn't taken them the night before.

