New Jersey is also north of the D fall winter production line.

I mentioned Northern Europeans because they have a hereditary genetic inability to make enough vitamin D from the sun. That's also why NEs have higher cancer risk. Those of African descent have the same problem at the other extreme, their dark pigmentation prevents them from making enough.

Do you have any links for that Northern European genetic stuff? I'm pretty interested in reading about it. I had always thought that the more fair you were, the easier it was to get enough on smaller amounts of sun exposure and was feeling pretty safe...but with German, Norway and Scotland in my background I'm not so sure.

This thread, which has slipped in, almost unnoticed, to the P & N section, has sure raised a lot of interest. Could this be because it is a controversial subject? For example, as mentioned in an earlier post, 7 hours sleep is my maximum and if ever I oversleep I usually suffer for it.

The suggestion of darkening one's room seems plausible but my experience informs me that it is not necessary in which to reach REM levels. Okay, so in the research done, a light is shone on the leg of the sleeper while in the REM state and it caused the sleeper to come out of the REM level. From this the authors deduced that light interferes with REM sleep, but, could they be wrong? Is this proof of the need for darkness or could it possibly be some other feature? Those like myself who have spent years sleeping in public institution dormitories (hospitals/armed forces, etc) where generally there is a night-light on at all times, were never unduly affected by it.

Furthermore, whenever I retire (usually in the wee sma' hours) I need only to think of the time to awake and I duly awaken then. Often, in my life, when something unexpected has occurred during the night, I have awoken in advance of the occurrence. The obvious questions here are, what part of my psyche (6th sense?) remains vigilant and what actually was it that the researchers were witnessing?

Regarding the darkened room, am I the only one who enjoys awakening to the sunshine pouring through the windows into my bedroom? In mid-summer, in this northern clime, on a cloudless night, it never gets darker than twilight and then only for about an hour yet my sleep is not disturbed. A similar situation arises whenever suffering from jet-lag when sleep, almost under any conditions, refreshes.

While it is recognised that there are those who require longer spells of undisturbed sleep, could this requirement be due to some other cause?

I admit I haven't read the book yet (so many books, so little time!) but I've found the discussion very interesting.

While I certainly agree that the average USerican is sleep deprived, I can't imagine that everyone needs a minimum of 9 hours.

I have the good fortune to work from home keeping my own hours. No kids to wake the household. Allowing my body to keep precisely the sleep schedule it wishes, I need between 7 hours 45 mins, and 8 hours 15 mins, and never more or less than that. And its been exactly the same for most of my life. I'm not actually physically capable of sleeping more except in extrordinary circumstances like illness or something.

Compare this to my husband, who has the same luxury of on-demand sleep, and who needs a minimum of 9 hours, sometimes more.

I don't sleep well past dawn, he sleeps perfectly well until the last hours of the morning. And my inability to sleep past dawn is not affected by an inability to see it. Lovely dark hotel rooms don't make any difference.

So, I think the ideas in the book (as reported in this thread) are interesting, and an interesting first pass at sleep research, I think there is a lot more personal variation in this, as with everything else.

I can never refind the exact article when I want. To paraphrase: As peoples moved north there were selections for genetic mutations for lighter skin which allowed for vitamin D synthesis under less strong sun. The further north people moved, the lighter the skin got. However, there came a time and place in the furthest north reaches where sun could not produce vitamin D most of the year even though the people got really, really pale. These peoples ate fish that was rich in vitamin D and so provided for D needs that way. So they survived. The fact that they were getting vitamin D from the sea and not from the sun allowed them to survive their environment with the result that over generations they reduced the number of vitamin D receptors in the skin (probably also due to the continual need for clothing due to the harsher environment). The lost receptors led to the inability to produce enough vitamin D from the sun, and a loss of the ability to tan (related to vitamin D synthesis and sun protection).

Thus lighter skin is a benefit to vitamin D synthesis until it is too light (of Northern European/Scandinavian heritage) at which point vitamin D synthesis is impaired and this impairedness(?) was passed along in the genes to suceeding generations.

This is why Northern European/Scandinavians and Blacks have correlating rates of cancers and high blood pressure. It's also why Scandinavian countries have higher incidences of MS, fibromyalgia, and CFS.

Interestingly, until the 70s, most Scandinavian countries mandated that children and pregnant women be given 2,000 IU/Day of vitamin D. Their rates of Diabetes Type I were much lower. Prenatal vitamin D deficiency has been linked to autism and schizophrenia.

These aren't the exact article I was searching for but give you the gist.
http://www.derm.med.ed.ac.uk/PDF/Am...on%202004 .pdf
The Genetics of Sun Sensitivity in Humans
Jonathan L. Rees
Systems Group, Dermatology, University of Edinburgh, Edinburgh

http://www.fao.org/docrep/W7336T/w7336t03.htm
The roles of calcium and vitamin D in skeletal health: an evolutionary perspective

http://www.derm.med.ed.ac.uk/PDF/Ge...in%20Colour.pdf
GENETICS OF HAIR AND SKIN COLOR
Jonathan L. Rees
Systems Group, Dermatology, University of Edinburgh, Lauriston Buildings, Lauriston
Place, Edinburgh, EH3 9YW, United Kingdom; email: jrees~staffmail.ed.ac.uk

It wasn't about REM sleep, it was about suppression of melatonin. There's no argument that nighttime suppression of melatonin is a bad thing.

There is, however, argument over light and suppression of melatonin. How much? At what time? What color? What part of the body? What time of the year? For how long? If you don't have enough to do, check out the raft of work that has been done since the original study: Here's a start.

As you can see, there's still no consensus, but even a brief look at the literature makes you want to block out the windows and be done with it.

Also, the work of Tom Wehr inspires me: Here.

The definition of "enough sleep" needs to be "enough time for the nighttime endocrine cycle to complete". Until we spend a week in a sleep lab spitting into test tubes, having blood drawn on the hour, with a rectal thermometer recording our temperature in hundredth-of-a-degree increments, helping us find out Our Own Personal Sleep Need, I think it's best to take the advice that--barring a serious sleep disorder--human nighttime endocrine cycle is not variable.

Just as more antecdotal evidence of sleep variance, I find my sleep requirements vary a great deal. I can 'get by' and remain functional for several days on 2-4 hours / night, but it does cause me to get grouchy and perhaps less mentally competent. However a nap of any length, but preferably an hour or longer will get me going again. I've also been known to nod off (not always intentionally) at moments when my attention is not actively required. I've even done this at live rock concerts, close to the stage... More regretably I used to do it frequently at work during meetings when my participation wasn't actively required...

Fortuneately, if I have an activity that does require my attention (such as driving) then I don't have trouble staying awake as needed.

This does act like sleep deprivation, but I'm not sure - I find that it is difficult for me to go to bed much before midnight, and if I do, I don't sleep.

OTOH, when I'm not required to get up in the morning, I can easily go for 8-10 hours (possibly with a 'hydraulic relief' break in the middle) or longer.

I prefer a dark space to sleep, but it isn't essential - again I have found that I can, and do, sleep under almost any lighting condition.
Even coffee or other caffeine source (the 100% pure, natural, organic, substitute for sleep) won't keep me awake if I feel like sleeping, but I do try to avoid it late in the day.

My beloved, on the other hand becomes non-functional if she doesn't get at least 6 hours / night, preferably 7-8. However a light doesn't bother her, indeed she usually goes to bed leaving a light and the radio on. I come in later and turn them both off.... It works.

Gooserider


Gooserider

It's not just with people... read this article...

Raising chickens indoors under constant light depresses their immune systems

Most of our commercial broilers are raised indoors in crowded sheds with the lights left on 23 hours a day. The constant lighting speeds their growth, getting them to market a few days earlier. But the unnatural light also depresses their immune system by suppressing their production of the immune-boosting hormone, melatonin. A new study reveals that birds with low levels of melatonin are more vulnerable to disease. The response of the poultry industry is to dose the beleaguered birds with more vaccines and antibiotics.

This is outside the norm. I was sleeping like this 7 years ago, then I had a sleep study done. Turns out I have a sleep disorder, sleep apnea. I was always tired, sleepy during the day even with 12 hours of sleep. I am now on CPAP, and feel so much better. Have you had a sleep study, or talked to a physician about this? Without treatment, untreated sleep apnea could lead to heart conditions or stroke, etc.

Turns out I also have an underactive thyroid, which was recently diagnosed. Both conditions are related (some people that have sleep apnea have hypothyroidism).

I'd definitely suspect thyroid, the other thought is narcolepsy.

Funny you should say that. I came to the narcolepsy conclusion awhile ago (all of my symptoms match up), but everyone else thinks I'm nuts. "Narcolepsy" sounds like such a 19th-century disease!

I'm skeptical about the sleep tests. It seems to me that if you were in such weird conditions (a lab type setting, hooked up with all sorts of wires, not in your own bed, etc) that you would not sleep normally.

Kallyn, have you ever had your thyroid tested? I know when my friends have had sleep tests done it was in their home. I agree though, it does seem like it'd be about impossible to fall asleep inside a lab.

I had a bit of a heart issue about 2 years ago, and they ran all sorts of tests. At that time, according to the work I got done, my thyroid was well within the normal range.

Also, like I said, I've had this sleep problem since I was a baby. (apparently I always slept through the night and it was really hard to wake me up)

I guess these things don't completely rule out subclinical thyroid problems, but they make me suspect narcolepsy instead.

EDIT: case in point, last night I slept from 11:45PM to 11:30AM, with a brief 30-min period of waking in which I drove my fiance to work. ;(

It is possible to have underactive thyroid from birth, but that usually involves a lot of problems like lower IQ and stuff. I agree, its more likely something else.

PD that's an interesting observation of the broilers but, what's more fascinating is that in almost all public institutions where there is a number sleeping in the one space, large hospital wards being the obvious example, there is always a nightlight and the irony is that this is where patients require a sound immune system for recovery purposes. The reason probably revolves around expediency, like what's more important; the nurses being able to see the patients or the patients' recovery? Another consideration could be, does the hospital exist for the benefit of the staff or the patients?