Category Archives: Sleep

Social Jet-Lag

From Financial Times: ‘Social jet lag’ causes fatigue and illness (also on MSNBC):

Half the people in modern urban societies suffer from “social jet lag” because their body clocks are seriously out of step with their real lives, the Euroscience forum in Munich heard on Monday.
The result was chronic fatigue and an increased susceptibility to disease, researches found. They concluded that employers should tell staff to wake up in their own time and come in to work when they feel ready to.
Till Roenneberg, a circadian rhythm researcher at Ludwig Maximilians University in Munich, coined the phrase “social jet lag” after a survey of 40,000 people in Germany and Austria – and a more detailed follow-up study of 500 – showed a persistent mismatch of at least two hours between their biological clocks and the demands of their jobs or education.
One striking research finding was that people suffering from social jet lag were much more likely to smoke. “Among those who had no social jet lag, 10 per cent smoked; at two hours the proportion was up to 30 per cent and at four hours we found 60 per cent smoked.”
Employers and schools could do a lot to help, by adjusting their working hours, said Martha Merrow of Groningen University in the Netherlands. “Schools should open later; I think 10am would be sensible but no one wants the inconvenience of making the change.”
According to Prof Roenneberg, “those people who suffer the least social jet lag are late types who can choose their own working times. Employers should say: ‘Please wake up in your own time and come in when you are ready.'”

And shorter take on ZDNet:

Computer-mediated work and networks, which bring groups together on radically different schedules than the 19th and 20th centuries’ work habits. We have an opportunity to rethink the organization of work. Should we start with recognizing schedules in shared workspaces need to be more flexible? I think so, especially when you consider that more work can be done at home, allowing people to spend time with their families and contribute to the raising of the next generation while continuing intense professional engagement with the economic world.

Amen, brother….

Wealthy white people get more sleep

I did not find it surprising. If you have money, you can buy yourself time – to exercise, to eat a good meal at a nice restaurant or to fix healthy food at home, and to sleep as much as your body needs. As a result, you will be healthier overall. You can read about the study here (hat-tip:Sleepdoctor)

All Politics Is Local

This week, it took me quite a while to figure out how to answer the Ask a ScienceBlogger question: “What are some unsung successes that have occurred as a result of using science to guide policy?”
As a relative newcomer to the United States, and even more a newcomer to American politics, I was not around long enough to pay attention to various science-driven policies of the past. Most of what I know are far from “unsung” successes – from Manhattan Project, through Clean Air and Clean Water acts, to the EWndangered Species Act, to the international Kyoto Protocol. Dealing with DDT, DES, thalidomide is also well-known. The space program is quite well sung! Various policies in other countries are also well known at least to the local population.
So, I thought, I should probably take a look at some issues that, informed by science, became policy at the state or local level. Then, my wife reminded me about the topic I know something about, as I have written about it several times before, e.g., here, here and here.
That’s right. Forward-looking school systems in reality-based communities around the country have, over the last several years, implemented a policy that is based on science – sending elementary school kids to school first in the morning, middle-schoolers next, and high-schooler last. This is based on the effects of puberty on the performance of the human circadian clock. For teenagers, 6am is practically midnight – their bodies have barely begun to sleep. Although there have been some irrational (or on-the-surface-economics-based) voices of opposition – based on conservative notions of laziness – they were not reasonable enough, especially not in comparison to the scientific and medical information at hand, for school boards to reject these changes.
So, click on the links above for my long-winded rants on the topic, both the science part and the policy part. I am very happy that my kids are going to school in such an enlightened environment, and I am also happy to note that every year more school systems adopt the reasonable starting schedules based on current scientific knowledge.

Sleep Experiment in Space

The absence of light-dark cycles in space (e.g., on the shuttle or space station) results in disruptions of sleep. It has been proposed that humans who spend prolonged time in space are suffering from jet-lag – the internal desynchronization of clocks in various tissues.
A new experiment on the space station will take a somewhat different strategy than usual. Instead of measuring EEG (brain activity), it will monitor EKG (heart activity) over a period of 150 days.
The idea, brought by Irish researchers, is that EEG monitoring is not capable of measuring internal desynchronization of the myriads of clocks in our body. If the astronauts are indeed jet-lagged, this may not be apparent from the measurement of brain function which presumably follows the timing of the main pacemaker in the suprachiasmatic nucleus. The new approach will also look at the timing of peripheral oscillators to see if they are out of sync with the brain – which would be the true marker of jet-lag.

Sexsomnia Revisited

The article I linked to in my previous post on the topic of having sex while asleep (or is it ‘being sleep while having sex’?), e.g., the one I got pointed to by someone (e-mail?), is actually, quite terrible. So, instead, if you are interested in the topic, you should check out a much more serious website –, which focuses entirely on the phenomenon of sexsomnia.
I need to thank Karmen for pointing out that site to me. The site has extensive links to other sources of information, including links to all of Dr. Shapiro’s papers on the topic. For instance, this paper (pdf) appears much more trustworthy than the little online survey mentioned in the article I linked a few days ago.
On a less scientific, but perhaps more exciting note, you should check out the story of a woman whose boyfriend left her because of sexsomnia (masturbating in her sleep). And, since the original article mentioned potential legal consequences of sexsomnia (e.g., having sex with a minor), there was a case in Canada last year in which they found a man innocent of rape because he suffered from sexsomnia (the weird part is, he woke up with a condom on!)


Sex While Sleeping Is Real, And May Be No Joke
It is a tiny study but the preliminary results are intriguing. The article does not go much into underlying biology, but it touches on possible legal ramifications. If walking, eating or driving while asleep is possible, why not having sex? After all, you don’t even have to get out of bed. What do you think?

Phase-Dependence of Rozerem Effectiveness?

Rozerem is a selective melatonin agonist. It acts on melatonin receptors at the suprachiasmatic nucleus. It is prescribed as a non-addictive sleep aid for people having difficulties with the onset of sleep, i.e., falling asleep in the evening.
While melatonin itself appears unlikely to be a molecule that directly induces sleep, it does have phase-resetting effects on the circadian clock. Thus, Rozerem appears ideal as an aid for extreme “owls” to help them fall asleep (if they need to wake up early in the morning, as some jobs require). By mimicking melatonin, it would phase-advance the clock by a couple of hours and make it easier to fall asleep at a more socially acceptable time.
I did not really spend much time thinking about this, but my wife just told me something interesting. Last night, she took Rozerem and fell asleep practically instantly and had a great night of sleep. But, last week, when she tried using Rozerem in the morning after coming back home from her 12-hour night shift, there was no effect.
Perhaps Rozerem, just like melatonin, is incapable of inducing instant 12-hour phase-shifts of the circadian clock in the SCN. Shifting by a couple of hours is fine, but shifting the cycle by 180 degrees is a different story altogether – it may take several days to accomplish.
Perhaps the clock in the SCN has its own Phase-Response Curve (PRC) to melatonin – presence of the molecule induces smaller or bigger (or not at all) phase-advances or phase-delays depending on the phase of the cycle in which it is applied.
So, perhaps Rozerem given in the evening hits the PRC at the phase in which a large (i.e., 2-3 hours) phase-advance is induced, thus placing the body at the right time for the onset of sleep. By the same logic, application of Rozerem in the morning may hit the PRC at the phase in which it has no effect or an effect in the wrong direction – phase-advance again, which would bring the body at the proper time for brunch! I guess I’ll need to dig through the old literature on the melatonin PRCs in humans to see how it looks like and if this notion may be correct.
Perhaps if one works a night shift and repeatedly applies Rozerem every morning, there would be a gradual shift of the clock, over several days, until the correct phase is achieved at which the drug would work as advertised. Also, avoiding any conflicting cues to the clock (e.g., light, noise, etc.) would seem important to ensure that a morning dose of Rozerem has its intended effect for night-shift workers. All of this is late-night speculation, though, so do not take my word for it. It is based on a single data-point. More research is needed….


My post about sleep has been translated by Davide ‘Folletto’ Casali into Italian, and posted on his blog. You can see the translated post here. If you can read Italian (and even you do not – just for fun, and to reward his hard work), go and look around his blog.

Take a Merlot pill?

Melatonin may be found in grapes

MILAN, Italy, June 16 (UPI) — Scientists in Italy say they have discovered that the grapes used in popular red wines may contain high levels of the sleep hormone melatonin.
Melatonin is naturally secreted by the pineal gland in the brain, especially at night, and it tells the body when it is time to sleep, according to researcher Iriti Marcello at the University of Milan.

Hey, hey, what do you say:

Until recently, melatonin was thought to be exclusively produced by mammals, but has recently been discovered in plants.

Excuse me, but we’ve known for decades that melatonin is produced by all vertebrates, many, many invertebrates, some protists (including sea kelp), and, yes many plants. Bananas are famous for their high melatonin content.

Iriti’s study, published in the Journal of the Science of Food and Agriculture, discovered high levels of melatonin in Nebbolo, Merlot, Cabernet Savignon, Sangiovesse and Croatina grape varieties.
“The melatonin content in wine could help regulate the circadian rhythm — sleep-wake patterns — just like the melatonin produced by the pineal gland in mammals,” says Marcello.
However, Richard Wurtman of the Massachusetts Institute of Technology, says he is unconvinced and believes further research is needed to determine whether the compounds discovered are melatonin — or something very similar.

Wonder why Wurtman said this? I’d need to look at the paper – why is it considered to be iffy. Melatonin assays are pain in the behind to do, but they work.
Anyone, whatever benefits melatonin may have to put one to sleep in the evening probably require imbibing vast quantities of wine which also contains alcohol which fragments sleep (or eating a few pounds of grapes not selected for table use) – thus countering the effects of melatonin. Cute idea, anyway.

Brain Region Linked To Fly Slumber

When a news release states that a brain region is crucial for something, one is led to believe that this is the MAIN center controlling that function. If it is crucial for thermoregulation than it is the center for thermoregulation and without it the animal does not thermoregulate. Or am I misunderstanding English (it is a second language for me, after all)?
So, when the article starts with: “Researchers at Northwestern University have pinpointed a brain area in flies that is crucial to sleep, raising interesting speculation over the purpose of sleep and its possible link with learning and memory,” I expect to see total sleep loss when the brain region is deleted. But, “How the mushroom bodies control sleep is uncertain, but Allada and colleagues show that if the area is destroyed chemically, flies sleep less,” suggesting that a sleep center (if such exists at all – it may be a distributed brain function even in insects) is elsewhere.
Both the Allada study and the Seghal study are excellent and the information is really exciting, but why does a news release have to go beyond, far beyond…

SAD is a different kind of depression

So, Wellbutrin is now officially a drug for treating Seasonal Affective Disorder. And chocolate is so unofficially. But, those may only take the edge off of the symptoms – they cannot affect the underlying causes.

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

This post is perhaps not my best post, but is, by far, my most popular ever. Sick and tired of politics after the 2004 election I decided to start a science-only blog – Circadiana. After a couple of days of fiddling with the templae, on January 8, 2005, I posted the very first post, this one, at 2:53 AM and went to bed. When I woke up I was astonished as the Sitemeter was going wild! This post was linked by BoingBoing and later that day, by Andrew Sullivan. It has been linked by people ever since, as recently as a couple of days ago, although the post is a year and a half old. Interestingly, it is not linked so much by science or medical bloggers, but much more by people who write about gizmos and gadgets or popular culture on LiveJournal, Xanga and MySpace, as well as people putting the link on their and stumbleupon lists. In order to redirect traffic away from Circadiana and to here, I am reposting it today, under the fold.
Update: This post is now on Digg and Totalfark. I urge the new readers to look around the site – just click on the little SB logo in the upper left corner. Also, several points made briefly in this post are elaborated further over on Circadiana, as well as here – just browse my Sleep category.

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