Saturday, January 08, 2005

Everything You Always Wanted To Know About Sleep (But Were Too Afraid To Ask)

This post (and this whole blog, actually) has moved. You can find this post republished here. Please adjust your links accordingly.


Blogger abhijit said...

Fantastic! Just fantastic! Now I can use science and logic in my defence!!!

11:52 AM  
Blogger I Am Dali said...

i was never too afraid to ask about any of that.

4:37 PM  
Blogger Erin Ptacek said...

What, exactly, is the importance of a lark/owl match in a relationship? Is it better for both people to be on similar schedules? Or, conversely is a complimentary relationship is better (say, if the couple has children that wake often during the night)?

6:08 PM  
Blogger Bora Zivkovic said...
Body-clock dilemma: "My boyfriend is a morning person -- and I'm definitely not."
Reset solutions You want to dance till dawn; he can't keep his eyelids open past 9 p.m. You're grumpy in the morning, while he's whistling a tune. It's no wonder there's a high divorce rate between owls and larks, says Matthew Edlund, M.D., director of the Center for Circadian Medicine in Sarasota, Fla., and author of The Body Clock Advantage: Finding Your Best Time of Day to Succeed in Love, Work, Play, Exercise (Circadian Press, 2004). Owl-lark couples can have a tough time with everything from socializing to sex, simply because their sleep-wake cycles aren't in harmony.

But there is hope, Edlund says. Couples can take steps to work with their mismatched biology. If he's a lark and you're an owl, for example, he can try exercising in the evening and using bright light to help him stay up later. And to get more in sync with his schedule, you can try a morning jog or bike ride in the sunshine.

The two of you may find that some of your more alert times overlap, such as midmorning and early evening, so plan recreational and romantic activities accordingly. On a positive note, being part of an owl-lark couple has one distinct advantage: Parents can take the child-care shift that best suits their body clocks.

6:18 PM  
Blogger gia said...

A friend of mine linked me to this article, and I'm fascinated at the things you say about teenage sleep cycles. I'm just 20 myself, but throughout my teenage years and even now I'm well-known to my friends as the only person in our age group who goes to bed early and wakes up early.

Though the times have fluctuated a bit, for as long as I can remember I've been in bed by 11pm and awake by 9am, with only a couple of handfuls of exceptions, during which times there were extenuating circumstances.

So I'm kind of curious-- would you say I'm simply outside the norm? Or that I set myself in a sleep pattern and so I've sort of gotten 'stuck' in it (not that I feel the need to change it)? Or am I within the normal boundaries?

1:11 AM  
Blogger Jojo said...

Fascinating reading!

I am an owl. Being single & unemployed for some time, I am able to sleep, eat and do whatever I want, whenever I want (i.e. until I get a job or my IRA runs out) :) I'm in my early 50's and have found myself sleeping more than when I was younger. I thought you need LESS sleep as you get older? Left to my own, I seem to be happiest time-shifted from most everyone else. Generally, I go to bed 4:00-5:30am, sleep 6.5-7 hours and then often take take a nap of about 1 hour between 4-7pm. I tend to eat dinner around 10:00-11:00PM. My owl tendencies have caused problems with relationships in the past. Interestingly, my mother was also a night owl. Is this a hereditary condition?

Lately, I've been monitoring my sleep (and other activities) in an Excel spreadsheet and it looks like I require 8 hours of sleep in total (though I never seem to be able to do it in one stretch). And I almost always want a nap in the afternoon (though I notice that didn't take a nap 12/30-1/4 which is why the 10 day total for Sleep 2 is low).

Average Sleep time (since 12/1/2004)
All dates.......7:07..........0:51........7:58
Last 5 days....6:47..........1:02........7:49
Last 10 days...7:03..........0:31........7:34
Last 30 days...7:10..........0:51........8:01

When I was working, this need to sleep in the afternoon would sometimes get me in trouble as I was caught napping or nodding at my desk or in a meeting. I should probably live in Spain, where I understand that they shut down for a period in the PM for a nap. That would be heaven!

Unlike most of the people in the USA, I don't drink coffee or soda, so don't depend on caffeine. But now and then, particularly in the winter, I might have a cup of green tea which contains some caffeine.

I generally don't have any problems falling asleep but I've used melatonin now and then. I don't like it though because it generally makes me feel groggy, particularly if I use it 2 or 3 days in a row.

I wonder if there is any correlation between total sleep time or cycles and length of life?

And how about dreams? That's an area I'm very interested in, particularly in my case as to why characters in my dreams mostly don't seem to be anyone that that I know or recognize. Why/how can/do you dream about people that you don't know, have never met, aren't from TV, etc.????

4:08 AM  
Blogger jackie said...

I was wondering: are there any known health side effects, i.e. chronic fatigue or immune depression, from teenagers being forced to wake up absurdly early? At the high school where I teach, the classes start at *7:25 in the morning*, meaning that most students are waking up before 6 and going to sleep at midnight, earliest. The students in first period classes appear comatose.

1:27 PM  
Blogger Bora Zivkovic said...

Random Electric - Thanks for the article. No, I am not working on a chronotype questionnaireand never taught at Oz. I've been toying with the idea of surveying the chronotypes of bloggers for a while now. I bet Cory would be interested. I am thinking about the best methodology for such a project. And yes, I am planning on writing a post dedicated to the cuprachiasmatic nucleus.

gia - most of the stuff in biology is normally distributed. You just seem to be on one tail of the bell curve.

Jojo - older people do not need less sleep. The sleep gets more fragmented with age, though. If you add up all the sleep episodes of a day, including all the naps, it all adds up to whatever duration of sleep you always had, e.g., 8 hours on average. Infants need about 16 hours of sleep. This need rapidly diminishes to about 10 hours for teenagers and about 8 hours for adults for the rest of their lives. Of course, the individual variations are great - some people really need only 4 hours, while others need 12. Those are extremes, though.

Total Sleep Deprivation will kill you (it kills rats in 28 days). Having a severe sleep debt is likely to be bad for your health so it may shorten your life indirectly. Rotating shift-work certainly can make you very sick.

The total number of sleep cycles does not correlate with longevity across animal species. Small animals tend to sleep more hours per day and live shorter lives, but I do not think this is causally connected - just a correlation (and there are many exceptions to the rule - large predators sleep longer than the size/lifespan curve would suggest).

For dreams - read "Mind at Night" by Andrea Rock. It is the most up-to-date book about sleep and dreams for lay public.

Jackie - There is no research I am aware of that studied health effects of early school hours on adolescents. However, you should petition your school board to switch the starting times between elementary and high school using the educational reasons which are well documented, i.e., comatose students don't learn much.

3:10 PM  
Blogger Bora Zivkovic said...

Thank you. I will compare this one with some others I have and will e-mail Till Roennenberg and ask him for his as that one appears to be the "standard" these days.

9:12 PM  
Blogger DANIELBLOOM said...

9:25 AM  
Blogger Scott said...

"Use the light box at appropriate times (dawn for owls, dusk for owls)."

I think you might want to shine it at a lark at dusk...

12:30 PM  
Blogger Bora Zivkovic said...

Ooops- typo. I will correct it immediatelly. Thanks.

9:36 PM  
Blogger Scott said...

Wow, that is a lot of information. A lot of very interesting information.
Thanks for sharing.

3:08 PM  
Blogger Jojo said...

How's this for a related story?

Ukrainian hasn't slept in 20 years

A 63-year-old man who hasn't slept for more than two decades has been told there is nothing wrong with him by doctors.

Ukrainian Fyodor Nesterchuk from the town of Kamen-Kashirsky said the last time he managed to doze off was more than 20 years ago.

"I can't remember the exact date and I don't know why it started, but all of a sudden I found it more and more difficult to nod off until eventually I was awake the entire night.

"I used to read boring scientific periodicals in the hope they would send me to sleep. But as soon as I felt my eyes getting droopy and put the magazine down, I would find myself wide awake again. I thought it would just be a phase but its gone on for over 20 years now and I've simply had to get used to it.

"Now when everyone else sleeps I get stuck into a good book," said Nesterchuk.

All attempts by doctors to put him to sleep have failed and they now say there's nothing wrong with the insurance broker.

Local doctor Fyodor Koshel who has examined Nesterchuk extensively and has been unable to make him fall asleep, said he has no idea of the cause of the insomnia and added medically there is nothing wrong with him.

"We have no idea why he can't sleep, maybe it's the result of a past illness. But pathologically speaking, he's not in any pain and so there isn't anything actually wrong with him," said Dr Koshel.

1:26 AM  
Blogger Bora Zivkovic said...

Clock News 11: The Myth of Sleepless People

1:28 AM  
Blogger Bora Zivkovic said...

I may not have been clear, but of course the owls and larks did not arise at the time of Edison and Tesla! I tried to imply in the very beginning of the post that there is an adaptive value in the existence of variation in the timing of sleep as somebody is bound to be awake at any point of the 24-hour cycle - important for survival of our ancestors out in the savannah!

10:51 AM  
Blogger Hank Roberts said...

>light box ...3-4 strong neon lightbulbs, balasts,

Correction -- you want fluorescents (plain cool white or good color triple-phosphor but definitely not "full spectrum" -- youdon't want the ultraviolet
-- driven with electronic ballasts (cheap enough, and they don't flicker or hum)

Be careful doing ANY electrical wiring while winter-depressed.

Be even more careful about what you build -- in particular, Neon lights are (a) not very bright, and (b) use very high voltage, trying to build one could easily be fatal. And it'd be the wrong kind of light anyhow. has good summary info on all of this, and the pricey equipment.

I agree, build your own. I have since about 1989.

Also, there's a decent dawn simulator now for $25:

11:14 PM  
Blogger Bora Zivkovic said...

Sorry - in Serbo-Croatian language every light that is in a tube is called "neon light". I should have been more precise.

11:16 PM  
Blogger Bora Zivkovic said...

It is interesting that, a whole year later, this post is the most popular one on this blog. I can see, though, that most people who come here, read this post and then leave.

Why don't you exporer this blog a little further? You can start with the homepage (or just click on the blog title). Alternatively you can explore it in chronological order, month by month, if you check the archives. Or you can dig through the categories (on the sidebar).

1:55 AM  
Blogger Russell said...

I've actually been doing a 12 hr night of true darkness for a few months (long story, yes every night). 13 hours right now, since it's winter. Yes, the typical pattern is as described, two sleeps - but this does vary, and adapt well to circumstances. Tire yourself right out and you may get one sleep that's longer than 7 1/2 hours. Get sick and you'll sleep a lot more, maybe even straight through. Start worrying a lot about why your girlfriend isn't there with you and you may be lucky to get one short sleep, etc...

8:43 PM  
Blogger Russell said...

On the bright light, go hydroponic. Costs a bit more, but if a little is good, more feels great, and the brighter the light the more you can move around the room doing dishes, watching TV, whatever. And they last - I've bought two bulbs in twenty years.

8:45 PM  
Anonymous Anonymous said...

I'm concerned about the topic of sleep quality. My concern is for extrapolating or optomizing the deep sleep period mentioned in this article.

Back in the early 1980s, I watched a documentary of an experiment that to my recollection (and interpretation) delved into the area of sleep deprivation. Essentially, the degree of difficulty increases in the first 3 weeks, stays the same during the second 3 weeks, and lessons in the last 3 weeks.

The degree of difficulty corresponded with the greater or lesser need for sleep. If someone were to go without sleep for a week, s/he might require a full day or so to catch up and feel normal again. By contrast, if someone were to go without sleep for 2 months, s/he may only need 2-4 hours of sleep to feel normal again.

With these givens in mind, I am curious as to how sleep deprivation on a bi-monthly scale would affect the quality or depth of sleep during the first 2 rem periods.

Also, I would appreciate it if anyone knows of a reference to this documentary (film) I've spoken of within. I would especially like to read an article on this topic. Unfortunately, I have no suitable key words to even look up the name of the film.


12:29 AM  
Anonymous Anonymous said...

Hey thanks for writing this article. I learned a ton from it and i actually understood the parts about ATP etc. because we just finished learning about it in bio class. Thanks again :)

4:58 PM  

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