Sunday, January 09, 2005

ClockNews #1

Recent Merrimack tragedy fits into all-too-common trend

While most crashes or near misses occur from 4 to 6 a.m. or midnight to 2 a.m., the next most common time is between 2 and 4 p.m. The Sanbornton crash occurred at about 3:30 p.m.

Yes, most traffic and industrial accidents happen very late at night, for obvious reasons, but many people are unaware of the "post-lunch dip" a period in the afternoon when the circadian clock tell the rest of the brain to fall asleep. This is a perfect time for a siesta, and in many countries stores close and all activity ceases between 2 and 5pm. The term is somewhat a misnomer, as eating lunch is not neccessary for the increase in sleepiness. Of course, the exact timing of the dip will be later for the owls and earlier for the larks.

Light Boxes Help Lift the Winter Blues

Use of a standard light box for five years works out to
"about $60 per year," Flory noted, "compared to about $300 to $500 per year for
Prozac or another of the SSRIs."

Michael Young, a SAD expert and
director of clinical training at the Illinois Institute of Technology in
Chicago, agreed that "light boxes are certainly the most effective treatment"
for seasonal depression.

So, a total of $300. Fancy ones go for $500. On the other hand, making one by yourself (a piece of board, a balast, four strong fluorescent lightbulbs, some wires, switches and plugs) will cost you about $30. And will do just as good a job as the box they are trying to sell you.

On the other hand:
New variations on light boxes are giving patients more
choices, he said, including devices called "dawn simulators." These devices --
hooked up to a bright light in the bedroom -- cause light to slowly grow in
intensity during the early morning hours, much as it would on a spring
"There's been less research done on dawn simulators compared to light
boxes, but the research that is out there seems to have gotten positive
results," said Young, who is also president of the non-profit Society for Light
Treatment and Biological Rhythms.

Now, that may be a good investement. Most of the research in chronobiology has involved square-wave light-dark cycles in the lab (abrupt switches of lights-on and lights-off). However, recearch in a variety of animals, from humans and hamsters (e.g., work of Michael Gorman and Jeff Elliott), to scorpions (Gertha and Gunther Fleissner's research), found that dawn-dusk simulation is a very important cue for resetting the clock. I will go into details of this in a later post.

Best Time to Seduce Someone Is...

You won't believe it. It's just before lunch. 11:55 a.m. to
be exact. Who knew?

This is an example of really bad science journalism. Where the heck did they find such precise times? I would say it is more like 11:55 + 3 hours or so. Such precision cannot possibly be ascribed to a biological population (i.e., 6,411,607,517 people according to the POPClock estimate: So, read the rest of the article with caution, and modify the information according to your own chronotype.


Blogger Todd said...

This comment is not related to the blog entry to which it is attached, but rather a general question (I didn't see a private email address linked here.)

You seem to have a great deal of knowledge about human sleep habits and a desire to discuss them, and I'm hoping you might be able to better educate me on the sleep disorder narcolepsy. If not, do you know of any good resources about the condition I could review?

After being diagnosed a few years ago, I've read all sorts of information about the symptoms, but I have found very little about the cause and how it might be best managed w/o the need for prescription drugs. It seems like most prescribed drugs only address symptoms of fatigue w/o actually dealing with the cause of that fatigue in the first place.

Any insights you can offer are appreciated (you can email me at If not, that's okay too. I'm just looking to learn more about my condition and your entries in this blog so far have been very interesting to read. Thanks!

12:54 PM  
Blogger coturnix said...

Well, my specialty are circadian clocks, not sleep (though I know enough to give a 50 minute lecture on sleep in college), so this is out of my league. I am looking for a sleep specialists for some guest-blogging in the future, though, so hang in there.

A few years back, studies of narcoleptic Doberman Pinchers led to the discovery of orexin, a neurochemical implicated in control of sleep and a hot topic of research these days. I'll see if I can find more....

12:50 AM  

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