Category Archives: Sleep

Clocks, sleep and non-visual photoreception on

I am not the only one on to write about circadian rhythms, sleep and (non-visual) photoreception. Over the years, my SciBlings have written about these and related topics as well. Here is a sampler – go and dig for more on their blogs.
Stimulant Improves Sleep
Locked-In Syndrome
Opioids and Sleep Disorders
Home Testing for Sleep Apnea?
Pure Hypomanics: Living Zippedy Doo Dah Lives?
SFN Update: Sleep Deprivation Impacts Memory, Reduces Hippocampal Activity
Data Faker Turns Himself In
Agomelatine: A New Approach For Depression
Casual Fridays: Dave FINALLY finishes analyzing the procrastination data
Just Give ’em Some Nyquil While You’re At It
The Long, Long Sleep
Scientist to Men: Don’t sleep over
Two Stories on Sleep
Why do I feel like I’m falling when I go to sleep?
Power naps work in improving memory performance
Daylight Savings Time Affects Heart Attack Incidence
Don’t Trust an Insomniac
The Perverse Imp
Dolphins stay alert after five straight days of round-the-clock vigilance
The Night-Shift and Naps
Intranasal Orexin/Hypocretin: The Ultimate Uptime Drug?
Sleep behaviour and sleep postures
Sleep loss & false memories
Thinking During Sleep
The value of a good night’s sleep
Sleep, Sex, and Drosophila
Chloral Hydrate (Alkyl halide sleep aid)
Sleep and Heat
Make sure you get some sleep — or at least some caffeine — before that test
The point of sleep, or, Do fruit flies dream of six-legged sheep?
Portable brain activity-recorder shows that sloths aren’t all that sleepy
Lonely people have less efficient sleep
Friday Sprog Blogging: cross-country travel and kid circadian rhythms.
Ask a ScienceBlogger: A Sun Ray a Day….
Drink Your Milk! Go Outside and Play! You Just Might Live Longer
Day Two At SICB
Bears are in on the Hoax, Too
Living Clocks of Arctic Animals
How to evolve a watch
Circadian Clock Neurons
Evolution of vertebrate eyes
The eye as a contingent, diverse, complex product of evolutionary processes
Rhabdomeric and ciliary eyes
Medicine and Evolution, part 6: Ivan Schwab on eye evolution
Eyes, Part One: Opening Up the Russian Doll
Eyes, Part Two: Fleas, Fish, and the Careful Art of Deconstruction
Have fun for the rest of the week…

Is your pilot too sleepy to land you safely?

Ask the pilot:

Ask yourself this: Whom would you prefer at the controls of your plane on a stormy night, a pilot who smoked a joint three days ago, or one who had six hours of sleep prior to a 13-hour workday in which he’s performed half a dozen takeoffs and landings? The first pilot has indulged in a career-ending toke; the second is in full compliance with the rules. I have to assume that the FAA realizes the foolery of such enforcement policies, but it nonetheless chooses to put its resources into drug testing and other politically expedient issues. Meanwhile it procrastinates, performing study after study and poring over data from NASA circadian rhythm experiments in an attempt to answer one of the world’s most perplexing questions: Is exhaustion a detriment to job performance?

The Scientist special topic: Sleep

Nice four articles:
The Gears of the Sleep Clock By Allan Pack:

When people have trouble sleeping–such as, in extreme cases, shift workers–those problems are not always rooted in disturbances in circadian rhythm, argues the University of Pennsylvania’s ALLAN PACK. Instead, his studies of sleep have shown that the master clock is only one player in the molecular control of sleep.

Sleep adjusts fly synapses by Bob Grant:

New findings support a controversial hypothesis about the biological role of sleep: Snoozing may be a way for the brain to clear clutter accumulated after a hard day of synapse forming and strengthening. Two Science studies published today suggest that the brains of sleeping Drosophila undergo an overall depression in synaptic strength and number, eliminating some minor neuronal connections while merely weakening stronger ones.

Disappearing Before Dawn By Kelly Rae Chi:

Gene expression studies are lending support to a new, somewhat counterintuitive hypothesis for why every animal sleeps. KELLY RAE CHI visits the University of Wisconsin-Madison, where scientists are gathering evidence suggesting that we need sleep to prune back synapses, which tend to increase in strength throughout the day.

Why sleep?:

Sleep takes up around a third of our lives, and is an object of fascination during the other two thirds. “I dreamt that…” is surely among the top 10 conversation topics of all time. Given this, it is surprising how little attention is paid to the anthropology of sleep. Intriguing (but too little) work has been done on sleep practices in nonindustrialized societies, 1 and there has been some engaging speculation about sleep patterns; 2 it all points to our Western conventions as being a behavioral outlier.

How to catch a fly sleeping:

John Zimmerman at the Center for Sleep and Respiratory Neurobiology explains a new technique for determining when a fly is sleeping or awake – a prerequisite for fly-based sleep research:

Daylight Saving Time

Yup, it’s tonight.
If you were around here a few months ago, the day after the Fall Back day, you probably read this post.
Disregarding the debate over rhetoric of science, that is probably my best, most detailed explanation for what happens to our bodies on those too strange days of the year – Spring Forward and Fall Back day.
Spring Forward is much more dangerous, so be very careful in the mornings next week, especially on Monday. Take it easy, get up slowly, be a little late for work if you can afford it. Life and health are more important than a few minutes of work and being punctual on a day like that.
And that post also contains a bunch of links at the bottom to other posts on the topic.

Meetings I’d like to go to….Part IV

SLEEP 2009:

23rd Annual Meeting of the Associated Professional Sleep Societies, LLC (APSS) will be held June 6-11, 2009, at the Washington State Convention and Trade Center in Seattle, Washington. The SLEEP meeting attracts the largest audience of sleep specialists in the nation. It is the only five and a half day meeting in the nation with scientific sessions and an exhibition hall focused solely on sleep medicine and sleep research.

Hmmm, always wanted to visit Seattle. And this sounds like a very bloggable conference. And I’d get to finally meet Archy….

Science Cafe – Sleep and Sleep Disorders

This month’s Science Cafe (description below) will be held on February 17th at The Irregardless Cafe. We will be meeting Dr. Yvette Cook from the Rex Hospital Sleep Disorders Clinic. She will be talking with us about sleep patterns and why people may have trouble getting a good night’s sleep. I have attached an article Dr. Cook recently wrote for a Rex Healthcare newsletter that you may find of interest. I hope that many of you can come – it should be a very interesting and informative discussion.
Sleep and Sleep Disorders
Tuesday, February 17, 2009
6:30-8:30 pm with discussion beginning at 7:00 followed by Q&A
Location: The Irregardless Café, 901 W. Morgan Street, Raleigh 833-8898
The significance of sleep and dreams has been a subject of interest for centuries. But it took discoveries by scientists (electrical activity of the brain, Rapid Eye Movement sleep) to spur the creation of a new clinical field — Sleep Medicine. The ensuing creation of the polysomnogram (sleep study) has been instrumental in helping sleep physicians evaluate different sleep disorders such as sleep apnea, restless legs, sleepwalking and narcolepsy. Now the general population and the medical community are beginning to recognize the impact of sleep disorders on society.
About the Speaker:
Yvette R. Cook is a Diplomate of the American Board of Sleep Medicine and Fellow of the American Academy of Sleep Medicine. She has a private practice in Cary (Cary Neurology & Sleep Disorders, Inc.) specializing in the field of sleep medicine and serves as Medical Director of Rex Sleep Disorders Center, an accredited Sleep Center devoted to the evaluation of patients with sleep disorders.

Does Tryptophan from turkey meat make you sleepy?

Does Tryptophan from turkey meat make you sleepy?It’s Thanksgiving tomorrow and the question (of the title of this post) pops up on the internets again. See SciCurious and Janet for the latest local offerings.
Short answer: we don’t know.
But there is endless speculation about it, each taking into account bits and pieces of information that we know about tryptophan and related physiology. The hypotheses tend to focus on:
a) Tryptophan itself, i.e., how it can get from food, through the intestine, through the bloodstream, to the brain and what it would do once there.
b) Serotonin, as a product of tryptophan metabolism, and how it can be produced (and where – in the brain or somewhere else) and what it would do once there.
I like to post and re-post, around this time of year, the third alternative, taking into account that serotonin is precursor of melatonin, that all the enzymatic machinery needed for transformation of tryptophan to melatonin operates in the intestine itself, that melatonin (unlike tryptophan) easily crosses the blood-brain barrier, and that melatonin does have some effect on sleepiness.
The posts (see the 2005, 2006 and 2007 versions) tend to elicit a lot of comments.
I am not claiming that this hypothesis is correct, just that it co-exists with other hypotheses that are just as untested as this one. Read it under the fold:

Continue reading

How to turn your alarm-clock into your worst enemy

Here are a few examples. One will feed you greasy bacon every morning. The other will donate to the GOP. Others will force you to perform either menial or mental tasks. I prefer a more gradual approach – a system that gradually increases the illumination in the room, the volume of sound (some pre-chosen music), etc. and only does something dramatic at the last, most critical point in time when you absolutely HAVE to get up.
funny pictures of cats with captions
more animals
[btw, check out the other pages on that site – there are some other cool inventions there, mixed up with some quite silly ones]

Spring Forward, Fall Back – should you watch out tomorrow morning?

If you live in (most places in) the United States as well as many other countries, you have reset your clocks back by one hour last night (or last week). How will that affect you and other people?
One possibility is that you are less likely to suffer a heart attack tomorrow morning than on any other Monday of the year. Why? Let me try to explain in as simple way as possible (hoping that oversimplification will not lead to intolerable degrees of inaccuracy).
Almost all biochemical, physiological and behavioral parameters in almost all (at least multicellular) organisms display diurnal (daily) rhythms and most of those are directly driven by the circadian clock (or, more properly, by the circadian system). Here is an old and famous chart displaying some of the peaks (acrophases) of various physiological functions in the human:
It may be a little fuzzy, but you can see that most of the peaks associated with the cardiovascular function are located in the afternoon. The acrophases you see late at night are for things like “duration of systole” and “duration of diastole” which means that the Heart Rate is slow during the night. Likewise, blood pressure is low during the night while we are asleep.
Around dawn, heart rate and blood pressure gradually rise. This is a direct result of the circadian clock driving the gradual rise in plasma epinephrine and cortisol. All four of those parameters (HR, BP, Epinephrine and Cortisol) rise roughly simultaneously at dawn and reach a mini-peak in the morning, at the time when we spontaneously wake up:
This rise prepares the body for awakening. After waking up, the heart parameters level off somewhat and then very slowly rise throughout the day until reaching their peak in the late afternoon.
Since the four curves tend to be similar and simultaneus in most cases in healthy humans, let’s make it easier and clearer to observe changes by focusing only on the Cortisol curve in the morning, with the understanding that the heart will respond to this with the simultaneous rise in heart rate and blood pressure. . This is how it looks on a day when we allow ourselves to wake up spontaneously:
But many of us do not have the luxury of waking up spontaneously every day. We use alarm clocks instead. If we set the alarm clock every day to exactly the same time (even on weekends), our circadian system will, in most cases (more likely in urban than rural areas, though), entrain to the daily Zeitgeber – the ring of the alarm-clock – with a particular phase-relationship. This usually means that the rise in cardiovascular parameters will start before the alarm, but will not quite yet reach the peak as in spontaneous awakening:
The problem is, many of us do not set the alarm clocks during the weekend. We let ourselves awake spontaneously on Saturday and Sunday, which allows our circadian clock to start drifting – slowly phase-delaying (because for most of us the freerunning period is somewhat longer than 24 hours). Thus, on Monday, when the alarm clock rings, the gradual rise of cortisol, heart rate and blood pressure will not yet be as far along as the previous week. The ring of the alarm clock will start the process of resetting of the circadian clock – but that is the long-term effect (may take a couple of days to complete, or longer.).
The short term effect is more dramatic – the ring of the alarm clock is an environmental stressor. As a result, epinephrine and cortisol (the two stress hormones) will immediately and dramatically shoot up, resulting in an instantenuous sharp rise in blood pressure and heart rate. And this sharp rise in cardiovascular parameters, if the heart is already damaged, can lead to a heart attack. This explains two facts: 1) that heart attacks happen more often on Mondays than other days of the week, and 2) that heart attacks happen more often in the morning, at the time of waking up, than at other times of day:
Now let’s see what happens tomorrow, the day after the time-change. Over the weekend, while you were sleeping in, your circadian system drifted a little, phase delaying by about 20 minutes on average (keep in mind that this is an average – there is a vast variation in the numerical value of the human freerunning circadian period). Thus, your cardiovascular parameters start rising about 20 minutes later tomorrow morning than last week. But, your alarm clock will ring an entire hour later than last week – giving you an average of a 40-minute advantage. Your heart will be better prepared for the stress of hearing the ringing than on any other Monday during the year:
Now let’s fast-forward another six month to the Spring Forward weekend some time in March or April of next year. Your circadian system delays about 20 minutes during the weekend. On top of that, your alarm clock will ring an hour earlier on that Monday than the week before. Thus, your cardiovascular system is even further behind (80 minutes) than usual. The effect of the stress of the alarm will be thus greater – the rise in BP and HR will be even faster and larger than usual. Thus, if your heart is already damaged in some way, your chances of suffering an infarct are greater on that Monday than on any other day of the year:
This is what circadian theory sugests – the greater number of heart attacks on Mondays than other days of the week (lowest during the weekend), the greatest number of heart attacks on the Monday following the Spring Forward time-change compared to other Mondays, and the lowest incidence of heart attacks on the Monday following the Fall Back time-change compared to other Mondays.
A couple of days ago, a short paper appeared that tested that theoretical prediction and found it exactly correct (Imre Janszky and Rickard Ljung, October 30, 2008, Shifts to and from Daylight Saving Time and Incidence of Myocardial Infarction, The New England Journal of Medicine, Volume 359:1966-1968, Number 18.). The authors looked at a large dataset of heart attacks in Sweden over a large period of time and saw that (if you look at the numbers) the greatest number of heart attacks happens on Mondays compared to other days of the week (and yes, the numbers are lowest during the weekend), the greatest number of heart attacks occur on the Monday following the Spring Forward time-change compared to Mondays two weeks before and after, and the lowest incidence of heart attacks happens on the Monday following the Fall Back time-change compared to Mondays two weeks before and after:
Thus, the predictions from the circadian theory were completely and clearly correct. But I was jarred by the conclusions that the authors drew from the data. They write:

The most plausible explanation for our findings is the adverse effect of sleep deprivation on cardiovascular health. According to experimental studies, this adverse effect includes the predominance of sympathetic activity and an increase in proinflammatory cytokine levels.3,4 Our data suggest that vulnerable people might benefit from avoiding sudden changes in their biologic rhythms.
It has been postulated that people in Western societies are chronically sleep deprived, since the average sleep duration decreased from 9.0 to 7.5 hours during the 20th century.4 Therefore, it is important to examine whether we can achieve beneficial effects with prolonged sleep. The finding that the possibility of additional sleep seems to be protective on the first workday after the autumn shift is intriguing. Monday is the day of the week associated with the highest risk of acute myocardial infarction, with the mental stress of starting a new workweek and the increase in activity suggested as an explanation.5 Our results raise the possibility that there is another, sleep-related component in the excess incidence of acute myocardial infarction on Monday. Sleep-diary studies suggest that bedtimes and wake-up times are usually later on weekend days than on weekdays; the earlier wake-up times on the first workday of the week and the consequent minor sleep deprivation can be hypothesized to have an adverse cardiovascular effect in some people. This effect would be less pronounced with the transition out of daylight saving time, since it allows for additional sleep. Studies are warranted to examine the possibility that a more stable weekly pattern of waking up in the morning and going to sleep at night or a somewhat later wake-up time on Monday might prevent some acute myocardial infarctions.

And in the quotes in the press release they say the same thing, so it is not a coincidence:

“It’s always been thought that it’s mainly due to an increase in stress ahead of the new working week,” says Dr Janszky. “But perhaps it’s also got something to do with the sleep disruption caused by the change in diurnal rhythm at the weekend.”

Dr.Isis has already noted this and drew the correct conclusion. She then goes on to say something that is right on the mark:

And, of course, my first thought is, what about all the other times we are sleep deprived by, you know, one hour. Is waking up in the middle of the night to feed Baby Isis potentially going to cause Dr. Isis to meet her maker early? In that case Baby Isis can freakin’ starve. But, this is the New England Journal of Medicine and Dr. Isis appreciates the innate need that authors who publish here have to include some clinical applicability in their work.

The authors responded to Dr.Isis in the comments on her blog and said, among else:

We wonder whether you have ever tried to publish a research letter somewhere. The number of citations (maximum 5!) and the number of words are strictly limited. Of course we are familiar with studies on circadian rhythms and cardiovascular physiology. There was simply no space to talk more about biological rhythms than we actually did.

But what they wrote betrays that even if they are familiar with the circadian literature, they do not really understand it. Nobody with any circadian background ever speculates about people’s conscious expectations of a stressful week as a cause of heart attacks on Monday mornings. Let me try to explain why I disagree with them on two points they raise (one of which I disagree with more strongly than the other).
1) Sleep Deprivation. It is important to clearly distinguish between the acute and the chronic sleep deprivation. Sleepiness at any given time of day is determined by two processes: a homeostatic drive that depends on the amount of sleep one had over a previous time period, and a circadian gating of sleepiness, i.e., at which time of day is one most likely to fall asleep. Sleep deprivation affects only the homeostatic drive and has nothing to do with circadian timing.
Humans, like most other animals, are tremendously flexible and resilient concerning acute sleep deprivation. Most of us had done all-nighters studying for exams, or partying all night with non ill effects – you just sleep off the sleep debt the next day or the next weekend and you are fine. Dr.Isis is not going to die because her baby wakes her up several times during the night. This is all part of a normal human ecology, and human physiology had adapted to such day-to-day variations in opportunities for sleep.
The Chronic sleep deprivation is a different animal altogether. This means that you are getting less sleep than you need day after day, week after week, month after month, year after year, with rarely or never sleeping off your sleep debt (“catching up on sleep”). As a result, your cognitive functions suffer. If you are a student, you will have difficulties understanding and retaining the material. If you are a part of the “creative class”, you will be less creative. If you are a scientist, you may be less able to clearly think through all your experiments, your data, and your conclusions. No matter what job you do, you will make more errors. You may suffer microsleep episodes while driving and die in a car wreck. Your immune system will be compromised so you will constantly have sniffles and colds, and may be more susceptible to other diseases.
And yes, a long term chronic sleep deprivation may eventually damage your heart to the extent that you are more susceptible to a heart attack. This means that you are more likely to suffer a heart attack, but has no influence on the timing of the heart attack – it is the misalignment between the natural circadian rhythms of your body and the social rhythms imposed via a very harsh stressor – the alarm clock – that determines the timing. Being sleep deprived over many years means you are more likely to have a heart attack, but cannot determine when. Losing just one hour of sleep will certainly have no effect at all.
Thus, the data presented in the paper have nothing to say about sleep deprivation.
2) Cytokines. These are small molecules involved in intercellular signaling in the immune system. Like everything else, they are synthesized in a diurnal manner. But they act slowly. Maybe they play some small part in the gradual damage of the heart in certain conditions (prolonged inflammation, for instance), thus they may, perhaps, have a role in increasing risk of a heart attack. But they play no role in timing of it. Thus they cannot be a causal factor in the data presented in the paper which are ONLY about timing, not the underlying causes. The data say nothing as to who will suffer a heart attack and why, only when you will suffer one if you do.
If I was commissioned to write a comprehensive review of sleep deprivation, I may have to force myself to wade through the frustratingly complicated and ambiguous literature on cytokines in order to write a short paragraphs under a subheading somewhere on the 27th page of the review.
If I had a severe word-limit and needed to present the data they showed in this paper, I would not waste the space by mentioning the word “cytokine” at all (frankly, that would not even cross my mind to do) as it is way down the list of potential causes of heart attack in general and has nothing to do with the timing of heart attacks at all, thus irrelevant to this paper.
So, it is nice they did the study. It confirms and puts clear numbers on what “everybody already knew for decades” in the circadian community. But their interpretation of the data was incorrect. This was a purely chronobiological study, yet they chose to present it as a part of their own pet project instead and tried mightily to make some kind of a connection to their favourite molecules, the cytokines, although nothing warranted that connection. Nails: meet hammer.
The fake-insulted, haughty and inappropriate way/tone they responded to Dr.Isis is something that is important to me professionally, as is there misunderstanding of both the role and the tone of science blogs, so I will revisit that issue in a separate post later. I promise. It is important.
But back to Daylight Saving Time. First, let me ask you (again) to see Larry’s post from last year, where you will find a lot of useful information and links about it. What is important to keep in mind is that DST itself is not the problem – it is the time-changes twice a year that are really troubling.
Another important thing to keep in mind is that DST was instituted in the past at the time when the world looked very different. At the time when a tiny sliver of the population is still involved in (quite automated and mechanized) agriculture, when electricity is used much more for other things than illumination (not to mention that even the simple incandescent light bulbs today are much more energy efficient than they used to be in the past, not to mention all the newfangled super-efficient light-bulbs available today), when many more people are working second and third shifts than before, when many more people work according to their own schedules – the whole idea of DST makes no sense any more.
Even if initially DST saved the economy some energy (and that is questionable), it certainly does not do so any more. And the social cost of traffic accidents and heart attacks is now much greater than any energy savings that theoretically we may save.
Furthermore, it now seems that circadian clocks are harder to shift than we thought in the past. Even that one-hour change may take some weeks to adjust to, as it is not just a singular clock but a system – the main pacemaker in the SCN may shift in a couple of days, but the entire system will be un-synchronized for some time as it may take several weeks for the peripheral clocks in the liver and intestine to catch up – leading to greater potential for other disorders, e.g., stomach ulcers.
The social clues (including the alarm clocks) may not be as good entraining agents as we thought before either, especially in rural areas where the natural lighting still has a profound effect.
Finally, the two time-change days of the year hit especially hard people with Bipolar Disorder and with Seasonal Affective Disorder – not such a small minority put together, and certainly not worth whatever positives one may find in the concept of DST. We should pick one time and stick with it. It is the shifts that cost the society much more than any potential benefits of DST.
Related reading:
Daylight Saving Time
Daylight Savings Time worse than previously thought
Sun Time is the Real Time
Seasonal Affective Disorder – The Basics
Lesson of the Day: Circadian Clocks are HARD to shift!
Lithium, Circadian Clocks and Bipolar Disorder
Everything You Always Wanted To Know About Sleep (But Were Too Afraid To Ask)

Sleep in animals – behavior and posture

Sleep researchers rarely pay attention to stuff like sleep position and sleep behavior, as opposed to EEG data, sleep duration, timing and patterns. But now Darren reviews that neglected aspect of animal sleep.
Also see my post on the same topic about the sleep behavior in whales.

New and Exciting in PLoS Biology and PLoS Medicine

Monday night – time to check out the new articles in PLoS Biology and PLoS Medicine:
Is Sleep Essential?:

Everybody knows that sleep is important, yet the function of sleep seems like the mythological phoenix: “Che vi sia ciascun lo dice, dove sia nessun lo sa” (“that there is one they all say, where it may be no one knows,” Wolfgang Amadeus Mozart and Lorenzo da Ponte [1790], Così fan tutte). But what if the search for an essential function of sleep is misguided? What if sleep is not required but rather a kind of extreme indolence that animals indulge in when they have no more pressing needs, such as eating or reproducing? In many circumstances sleeping may be a less dangerous choice than roaming around, wasting energy and exposing oneself to predators. Also, if sleep is just one out of a repertoire of available behaviors that is useful without being essential, it is easier to explain why sleep duration varies so much across species [1-4]. This “null hypothesis” [5-7] would explain why nobody has yet identified a core function of sleep. But how strong is the evidence supporting it? And are there counterexamples?

SciCurious reviews this article as well.
Whisker-Mediated Texture Discrimination:

Our sense of touch provides information about nearby objects that can affect us in an immediate way. Texture, a central component of touch, is sensed quickly, even before an object is explored to measure its size, shape, or identity. To learn how contact with a surface produces a sensation of texture, many laboratories have examined the whisker system of rodents. Touch sensed through the whiskers in rodents works differently than touch sensed through the fingertips in primates. Touch receptors in the fingertips are distributed in a continuous sheet; this spatial distribution of inputs gives important signals about texture [1]. In contrast, rodents use a set of roughly 30 whiskers on each side of the snout, palpating surfaces through a 5-15 Hz forward-backward motion known as “whisking.” When a whisker’s tip or shaft makes contact with a texture, its movement changes; whisker motion signals report to the brain what the whiskers have contacted.

Where Does Bluetongue Virus Sleep in the Winter?:

Bluetongue virus (BTV) is spread by the bites of Culicoides midges (Figure 1), and can infect ruminant livestock such as cattle, sheep, and goats, wild ruminants such as deer, and camelids. Some infected animals develop the disease known as bluetongue, with clinical signs ranging from apathy and weight loss to swollen heads, tender feet and death (Figure 2). Historically a tropical and subtropical disease, bluetongue has become a regular visitor to southern Europe in the last decade [1,2]. Although growth in the global trade in livestock may have increased the frequency with which exotic viruses are introduced into Europe, the increasing tendency of those introduced strains to persist and spread is probably best explained by changes to the European climate [3], and several direct and indirect links between climate and BTV transmission have been identified [2]. BTV reached northern Europe for the first time in 2006, and affected around 2,000 holdings before reports ceased in early January 2007. The outbreak then re-emerged months later [4] and spread to a further 45,000 holdings by the end of the year, making it the most economically damaging outbreak of bluetongue ever seen [2,5].

SAW: Breaking Down Barriers between Art and Science:

The path to specialization of knowledge starts early. By the time children leave primary school, they have already been taught to view subjects like biology, art, and social studies as unrelated disciplines rather than as interlocking pieces that together lay the foundation for a deeper understanding of the world. The divisions between science, the arts, and the humanities are reinforced in high school, where each subject is taught by a different instructor under pressure to “teach to the test,” a practice that further isolates subjects, stifles inquisitiveness, and quells creativity. By the time we become specialists as adults, our ability to recognize connections between disciplines tends to diminish even further–often at a price. If during this process, we lose the ability to communicate with other groups of specialists (for example, chemists, physicists, and mathematical modelers) or with those who have not had any formal science education beyond high school (which would include many taxpayers, politicians, and policy makers), if we become unresponsive to the needs of society, then our value to society becomes compromised. And the question arises: how do we break down these barriers or prevent them from becoming established in the first place, without compromising the standards of the different disciplines?

Effect of the California Tobacco Control Program on Personal Health Care Expenditures:

Large state tobacco control programs have been shown to reduce smoking and would be expected to affect health care costs. We investigate the effect of California’s large-scale tobacco control program on aggregate personal health care expenditures in the state. Cointegrating regressions were used to predict (1) the difference in per capita cigarette consumption between California and 38 control states as a function of the difference in cumulative expenditures of the California and control state tobacco control programs, and (2) the relationship between the difference in cigarette consumption and the difference in per capita personal health expenditures between the control states and California between 1980 and 2004. Between 1989 (when it started) and 2004, the California program was associated with $86 billion (2004 US dollars) (95% confidence interval [CI] $28 billion to $151 billion) lower health care expenditures than would have been expected without the program. This reduction grew over time, reaching 7.3% (95% CI 2.7%-12.1%) of total health care expenditures in 2004. A strong tobacco control program is not only associated with reduced smoking, but also with reductions in health care expenditures.

I hope you don’t faint while reading this post….

…but if you do, I hope it was enjoyable! And edifying, of course. Kind of science that is amenable to experimentation at home.

Light and Time

Two of my SciBlings have recently covered papers that my readers should find interesting:
Joseph: Bright Light and Melatonin Treatment Improves Dementia:

A study published in JAMA indicates that treatment with bright light alone (1,000 lux), or bright light combined with melatonin, can improve symptoms in patients with dementia. Melatonin alone appeared to have a slight adverse effect.

Chris Chatham : Time Perception: In the Absence of “Time Sensation?”:

In their newly in-press TICS article, Ivry and Schlerf review the state of the art in cognitive modeling of time perception – perhaps the most basic form of perception which has no sensory system dedicated to it.

My picks from ScienceDaily – Sleep edition

Circadian Math: 1 Plus 1 Doesn’t Always Equal 2:

Like a wristwatch that needs to be wound daily for accurate time-telling, the human circadian system — the biological cycles that repeat approximately every 24 hours — requires daily light exposure to the eye’s retina to remain synchronized with the solar day. In a new study published in the June issue of Neuroscience Letters, researchers have demonstrated that when it comes to the circadian system, not all light exposure is created equal.

Morningness Is A Predictor Of Better Grades In College:

Morningness is a predictor of better grades in college, according to a research abstract that will be presented on June 9 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS). The study, authored by Kendry Clay, of the University of North Texas, focused on 824 undergraduate students who were enrolled in psychology classes. The subjects completed a health survey which included questions regarding sleep habits and aspects of daytime functioning.

Evening-type College Students On Early Daytime Class Schedules At A Disadvantage:

Eveningness is associated with not only later phases of a person’s sleep-wake cycle, but also with sleep irregularities, more pronounced sleep restriction during the week, and higher sleep compensation on weekends. Evening type college students may, therefore, need a sleep education that helps them adjust to imposed morning schedules, and would probably benefit from later class schedules, according to a research abstract that will be presented on June 10 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Excessive Mobile Phone Use Affects Sleep In Teens, Study Finds:

Teenagers who excessively use their cell phone are more prone to disrupted sleep, restlessness, stress and fatigue, according to a research abstract that will be presented on June 9 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Is ADHD An Advantage For Nomadic Tribesmen?:

A propensity for attention deficit hyperactivity disorder (ADHD) might be beneficial to a group of Kenyan nomads, according to new research. Scientists have shown that an ADHD-associated version of the gene DRD4 is associated with better health in nomadic tribesmen, and yet may cause malnourishment in their settled cousins.

Poor Sleep May Increase Odds Of Emotional, Behavioral Disturbances Including ADHD:

Insufficient sleep among adolescents may not only contribute to lower grades and a lack of motivation, but may also increase the odds of serious levels of emotional and behavioral disturbances, including ADHD, according to a research abstract that will be presented on June 9 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Bright Light Therapy May Improve Nocturnal Sleep In Mothers:

Bright light therapy may improve a mother’s nocturnal sleep, decrease daytime sleepiness and be beneficial to her well-being, according to a research abstract that will be presented on June 9 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Extra Sleep Improves Athletic Performance:

Getting extra sleep over an extended period of time improves athletic performance, mood and alertness, according to a research abstract that will be presented on June 9 at the SLEEP 2008 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS) in Baltimore, Md.

Fat Intake Negatively Influences The Sleep Pattern In Healthy Adults:

Total fat intake and dinner fat intake seem to influence negatively the sleep pattern in healthy adults, according to a research abstract that will be presented on June 10 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Ethical Implications Of Modifying Lethal Injection Protocols:

A team of medical, ethical, and legal scholars argues in PLoS Medicine that in some US states the modification of lethal injection protocols is tantamount to experimentation upon prisoners without the prisoners’ consent and without any ethical safeguards.

Major League Baseball Teams With Greater Circadian Advantage Are More Likely To Succeed:

The magnitude of circadian advantage influences the outcome of Major League Baseball (MLB) games in that teams with greater circadian advantage are more likely to win, according to a research abstract that will be presented on June 10 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Sleepy Driving Highly Prevalent Among College Students:

A high prevalence of sleepy driving is reported among college students, according to a research abstract that will be presented on June 9 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Poor Sleep Quality And Insomnia Associated With Suicidal Symptoms Among College Students:

Poor sleep quality and insomnia are significantly associated with suicidal symptoms among college undergraduates, according to a research abstract that will be presented on June 9 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Decreased Total Sleep Time Associated With Increased REM Sleep During Subsequent Naps:

Decreased nightly total sleep time, even within the normal range, is associated with an increased percentage of REM sleep during subsequent naps, according to a research abstract that will be presented on June 10 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Insomnia Among Returning War Vets Is As Severe As Patients With Chronic Insomnia:

Insomnia together with post-deployment adjustment disorders among returning war veterans is as severe as patients suffering from chronic insomnia, according to a research abstract that will be presented on June 10 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Prenatal Drug Exposure Linked To Sleep Problems In Children:

In the first study across time into late childhood of the effects of prenatal drug exposure on sleep, prenatal drug exposure is associated with greater sleep problems in children. In addition, nicotine has a unique effect, and early sleep problems predict later sleep problems, according to a research abstract that will be presented on June 10 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

Sleep Problems Linked To Obesity, Lower Quality Of Life In School-aged Children:

A research abstract that will be presented on June 10 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS), finds an increased prevalence of sleep problems among school-aged children who are obese and an association between increased weight and lower quality of life.

Link Between Migranes And Sleep Disorders In Children:

Children with a migraine headache are more likely to have sleep disorders, such as obstructive sleep apnea (OSA) and lack of sleep, than children without a migraine, according to a research abstract on the effects of headaches on children’s sleep patterns that will be presented on June 10 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

(Non) Adaptive Function of Sleep

(Non) Adaptive Function of SleepFrom November 01, 2005, a review of a review…

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Development of the human sleep patterns

Development of the human sleep patternsWhat it really means when we are talking about babies “sleeping through the night” (from September 22, 2005)

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When Should Schools Start in the morning?

When Should Schools Start in the morning?The fourth part of a four-part series on the topic, this one from April 02, 2006….

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More on sleep in adolescents

More on sleep in adolescentsThis is the third part of the series on the topic, from April 01, 2006…

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Sleep Schedules in Adolescents

Blogging on Peer-Reviewed Research
Blogging on Peer-Reviewed Research

Sleep Schedules in AdolescentsEarlier this year, during the National Sleep Awareness Week, I wrote a series of posts about the changes in sleep schedules in adolescents. Over the next 3-4 hours, I will repost them all, starting with this one from March 26, 2006. Also check my more recent posts on the subject here and here…

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Adolescent Sleep Schedule

From the ArchivesThis kind of ignorant bleating makes me froth at the mouth every time – I guess it is because this is my own blogging “turf”.
One of the recurring themes of my blog is the disdain I have for people who equate sleep with laziness out of their Puritan core of understanding of the world, their “work ethic” which is a smokescreen for power-play, their vicious disrespect for everyone who is not like them, and the nasty feeling of superiority they have towards the teenagers just because they are older, bigger, stronger and more powerful than the kids. Not to forget the idiotic notions that kids need to be “hardened”, or that, just because they managed to survive some hardships when they were teens, all the future generations have to be sentenced to the same types of hardships, just to make it even. This is bullying behavior, and disregarding and/or twisting science in the search for personal triumphalism irks me to no end.

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Books: “Snooze…Or Lose! – 10 “No-War” Ways To Improve Your Teen’s Sleep Habits” by Helene A. Emsellem, MD

Snooze%20or%20Lose.jpgMy regular readers are probably aware that the topic of adolescent sleep and the issue of starting times of schools are some of my favourite subjects for a variety of reasons: I am a chronobiologist, I am an extreme “owl” (hence the name of this blog), I am a parent of developing extreme “owls”, I have a particular distaste for Puritanical equation of sleep with laziness which always raises its ugly head in discussions of adolescent sleep, and much of my own research is somewhat related to this topic (see the bottom of this post for Related Posts).
So, I was particularly pleased when Jessica of the excellent Bee Policy blog informed me of the recent publication of a book devoted entirely to this topic. Snooze…or Lose! by Helen Emsellem was published by National Academies and Jessica managed to get me an Advanced Reading Copy to review.

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Do androids dream of electric sheep? Sure, if they sleep.

To sleep or not to sleep: the ecology of sleep in artificial organisms:

We systematically varied input parameters related to the number of food and sleep sites, the degree to which food and sleep sites overlap, and the rate at which food patches were depleted. Our results reveal that: (1) the costs of traveling between more spatially separated food and sleep clusters select for monophasic sleep, (2) more rapid food patch depletion reduces sleep times, and (3) agents spend more time attempting to acquire the ‘rarer’ resource, that is, the average time spent sleeping is positively correlated with the number of food patches and negatively correlated with the number of sleep patches.
Collectively, the output suggests that ecological factors can have striking effects on sleep patterns. Moreover, our results demonstrate that a simple model can produce clear and sensible patterns, thus allowing it to be used to investigate a wide range of questions concerning the ecology of sleep.

The Open Sleep Journal and The Phylogeny of Sleep Database

One of the latest additions (just two days ago, I think) to the Directory of Open Access Journals is a journal that will be of interest to some of my readers – The Open Sleep Journal. The first volume has been published and contains several interesting articles. One that drew my attention is The Phylogeny of Sleep Database: A New Resource for Sleep Scientists (PDF download) by Patrick McNamara, Isabella Capellini, Erica Harris, Charles L. Nunn, Robert A. Barton and Brian Preston. It describes how they built a database that contains information about sleep patterns in 127 mammalian species. The Database itself can be found here and one can search it by species, by what was measured, by physiological or environmental conditions in which sleep was measured, etc. It has links to research on everything from platypus and echidna, through humans and kangaroos, to elephants, giraffes and sloths.
Since one of the stated projects that will come out of the database is a publication of a book on the Evolution of Sleep, I looked around to see if they are interested in anything else apart from mammals. Looking at the Projects page, I see they intend to add birds to the database later on. But that is not enough. Sleep did not suddenly appear full-blown in mammals and separately in birds. There is a long history of sleep research in reptiles, amphibians and fish, as well as – more recently – in insects like cockroaches, honeybees and Drosophila. In order to study the origin, evolution and adaptive function of sleep we have to look at its precursors among the invertebrates, not just focus on mammals and birds.

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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A nice brief tutorial on sleep

On Brain Rules

Post-doc with a leading Sleep research group

Charles A. Czeisler, Steven W. Lockley, Christopher P. Landrigan, Laura K. Barger
Harvard Work Hours, Health and Safety Group
Division of Sleep Medicine, Brigham & Women’s Hospital, Harvard Medical School
The Harvard Work Hours Health and Safety Group focuses on understanding the consequences of extended work hours and disordered sleep schedules on health and safety across a range of professions and populations. We also develop and test countermeasures to prevent the increased risk of accidents and injury for both worker health and public safety with the long-term aim of providing data to inform evidence-based policy and legislative decisions. Recently, we have addressed the impact of reducing extended duration (>24 h) work shifts on physician health and patient safety and developed and tested a comprehensive sleep disorders screening and fatigue management program in several police forces.
We seek a post-doctoral fellow to join our team who will participate in ongoing projects and develop new research initiatives. These projects will primarily be ‘field-based’ programs involving data collection under real-world conditions but conducted using robust clinical trial designs. The Division of Sleep Medicine is interdisciplinary, with members from backgrounds in physiology, psychology, medicine, and mathematics and the successful candidate will be encouraged to collaborate within and outside the Division as they pursue their research interests. The rich environment of the Division of Sleep Medicine ( offers many opportunities for career development and education.
The candidate will have knowledge of clinical study design and experimental statistics. Candidates with experience in field- and/or laboratory based clinical trials are encouraged to apply. A background in Sleep Medicine is desirable but not required. An educational program in Sleep Medicine will be provided which the candidate will be expected to attend. The initial appointment will be for 2 years, renewable annually thereafter.
Interested candidates should send a letter of interest, curriculum vitae, and contact information for three references in hard copy and electronic format to:
Steven W. Lockley PhD
Division of Sleep Medicine
Brigham and Women’s Hospital
221 Longwood Ave
Boston MA 02115

‘Insomnia: A Cultural History’

Book excerpt in today’s Wall Street Journal: Chapter 6: Wired:

It is likely that insomnia will increase with the expansion of the 24-hour economy into more and more lives, and more of each life, because wakefulness and the wired world go together. The more interconnected we are, the more we communicate, and the more we communicate, the more we rely on our interconnected powers of thinking. In addition to work, many of our leisure pursuits, while seemingly soporific, actually undermine the likelihood of restful sleep, from drinking alcohol to surfing the net to watching thrillers on late-night television. At the same time, these are often required to enable the passage between our increased workday and our decreased sleeping night to occur at all. In some cases, our leisure and workday activities may be conflated by medium — many of us use computers or mobile phones at work, and go on line or into text-mode for personal, leisure-related reasons as well. Or our sleeping times may be disrupted by shift work necessarily done while others sleep or in cognisance of the fact — as in the financial sector — that at any moment somewhere in the world the populace is working and awake, and that there is no time to lose in speculating upon its — or its capital’s — futures.

It is longish but worth your time.

My picks from ScienceDaily (the Sleep edition)

Daytime Nap Can Benefit A Person’s Memory Performance:

A brief bout of non-REM sleep (45 minutes) obtained during a daytime nap clearly benefits a person’s declarative memory performance, according to a new study.

People Had More Intense Dreams After Sept. 11, 2001, Sleep Research Shows:

The terrorist attacks of September 11, 2001, changed our lives in a number of different ways, not only socially and politically, but also in the way in which we dream, according to a new study.

Election 2008: Sleep Deprivation A Tough Opponent For Presidential Candidates:

The field of presidential contenders dwindled Wednesday when former New York Mayor Rudy Giuliani and former Sen. John Edwards (D-N.C.) dropped out of the race. As Super Tuesday approaches, however, the Democratic and Republican frontrunners will continue to face a formidable challenge from sleep deprivation.

Brain Region That Can Be Stimulated To Reduce The Cognitive Deficits Of Sleep Deprivation Identified:

A Columbia University Medical Center research team has uncovered how stimulation of a particular brain region can help stave off the deficits in working memory, associated with an extended sleep deprivation.

Periodic Leg Movements Predict Total Sleep Time In Older People With Cognitive Impairment, Sleep Disturbance:

A higher periodic leg movement index (PLMI) predicted less sleep at night in older people with cognitive impairment and sleep disturbance, according to a new study.

Respiratory Disturbances During Sleep Increase Significantly With Age:

The frequency of respiratory disturbances increases dramatically with age, even in healthy individuals without symptoms or signs of obstructive sleep apnea syndrome, according to a new study. An increase in the prevalence of sleep apnea syndrome with age has been well documented. This study focused on breathing irregularities during sleep in 163 people who are currently completely healthy, as assessed by passing numerous physical and clinical health tests. The results showed that, in this group of currently completely healthy individuals, irregularities in breathing during sleep are remarkably common, particularly in older individuals.

Four Days Of REM Sleep Deprivation Affects Forebrain, Long-term Memory In Rats:

Four days’ exposure to a REM sleep deprivation procedure reduces cell proliferation in the part of the forebrain that contributes to long-term memory of rats, according to a new study.

Changes In Narcoleptics’ Skin, Core Body Temperatures Affect Their Vigilance And Sleepiness:

In healthy people, both sleepiness and vigilance show a relationship with core body temperature and skin temperature. When core body temperature is high during the daytime, skin temperature is low, which translates into optimal vigilance. Conversely, when core body temperature is low at night time, skin temperature is high, which correlates to optimal sleep. Among those suffering from narcolepsy, however, direct manipulations of their skin and core body temperatures affect their vigilance and sleepiness, according to a new study.

Genetics and Biochemistry of Sleep

Keystone sleep/circadian meeting. Jay Dunlap, Emmanuel Mignot and Amita Seghal are organizing a Keystone meeting on Genetics and Biochemistry of Sleep in Lake Tahoe, March 7-12 (click here to see large):

A Sleeping and Dreaming Exhibit

Sleeping & Dreaming exhibit hosted by Wellcome Trust will be open until 9 March 2008:

Why are scientists still perplexed by sleep? What do the insights that our dreams bring us mean? And is a life without sleep conceivable? Sleeping and dreaming is a nightly (or daily) occurrence for us all, yet we still know relatively little about this elusive phenomenon.

If you are in London between now and early March, try to go and see it (and let me know how it was – perhaps blog about it and send me the link).

Evolution and Adaptive Function of Sleep

The panel discussion from the ‘Waking Up To Sleep’ (February 9th and 10th, 2007) conference has been filmed and the video is now online. A very interesting discussion on the evolution and adaptive function of sleep. Watch it here.
More videos of individual talks are here (hat-tip to reader NBM)
Related: (Non) Adaptive Function of Sleep

Sleep Apnea webcast

Dmitriy Kruglyak posted a summary of last week’s Cephalon webcast. The topic was Sleep Apnea, something I guess a number of my readers would be interested in. So, go ahead and listen to the podcast and read Dmitry’s summary and you can ask him additional questions in the comments.

Hypnic Jerk

No, that is not a really nasty guy who hypnotizes people. It is a technical term used to describe the feeling of falling one sometimes experiences at the moment one drifts into sleep. It often makes the person wake up again. I have not experienced it as kid, and even now it happens to me only rarely, when I am extremely exhausted at the time I finally get to go to bed.
But if you want to know more about this phenomenon and little that is known about its causes, head on to Pure Pedantry where Jake Young explains it.

Brain, Symmetry and Sleep

Hmm, I did not know this – apparently the left hemisphere of the human brain falls asleep first, and the right one a little bit later in most people.
I wonder if that has any connection with the reason we tend to focus on the right side of the face when someone is talking to us – checking the vigilance/sleepiness state of the person?

Sleep News

All-Nighters Equal Lower Grades:

With end-of-semester finals looming, here’s an exam question: Will pulling an all-nighter actually help you score well? To the dismay of college students everywhere, the correct answer is “no.”

Morning Jolt Of Caffeine Might Mask Serious Sleep Problems:

With the holiday season’s hustle and bustle in full swing, most of us will race to our favorite coffee shop to get that caffeine boost to make it through the day. However, that daily jolt that we crave might be the reason we need the caffeine in the first place.

Insufficient Sleep Raises Risk Of Diabetes, Study Suggests:

The most common factors believed to contribute to diabetes are a decreased amount of physical activity and access to highly palatable processed foods. However, there is growing evidence that another aspect of our modern lifestyle, short sleep duration, is also contributing toward the “diabetes epidemic”, according to a new study.

Sleeping with the New York Times

Being out of town and all, I missed it, but NYTimes published a whole lot of articles about sleep yesterday.
Of course, as I enjoy poking around bird brains, the article by Carl Zimmer – In Study of Human Patterns, Scientists Look to Bird Brains – was the one most interesting to me personally. But you may find the other articles interesting as well:
From Faithful Dogs and Difficult Fish, Insight Into Narcolepsy
At Every Age, Feeling the Effects of Too Little Sleep
In the Dreamscape of Nightmares, Clues to Why We Dream at All
An Active, Purposeful Machine That Comes Out at Night to Play
The Elderly Always Sleep Worse, and Other Myths of Aging
Sleep Drugs Found Only Mildly Effective, but Wildly Popular
Eyes Wide Shut: Thoughts on Sleep

Less you sleep, craziest the dreams!

There is an intriguing article in Scientific American about the consequences of sleep deprivation. When the brain is finally allowed to catch up with sleep, it tries to make-up for the loss of slow-wave sleep, but it also tries to make up for the loss of REM sleep as well – by making it more intense! As a result, the dreams are like scenes from something like “Jumanji” – wild animals running around and other crazy stuff. A very good article about various ideas on the function of sleep and dreams.

Yes, delay the school starting times

From the Independent:

The head has identified research which says that teenagers would be more likely to take in what they are learning if they started school two hours later. He is considering changing the school timetable for sixth-formers as a result.
“We have always assumed that learning early in the morning is best, probably because it is best for young children and adults,” he writes. ” Unfortunately, it is not true for teenagers. When teenagers are woken up at our morning time, their brain tells them they should be asleep. So they use stimulants such as coffee and cigarettes to get themselves awake. But at night, when we go to sleep, their neurological clock tells them it’s not time to sleep so they drink alcohol or take drugs to get them to sleep.
“Schools and universities only make it worse, he adds. The importance of neurological patterns of time as a factor in our learning and our lives has largely been ignored. We need to fit learning to these patterns of times. ”

(Hat-tip: nbm)

Do whales sleep?

Do whales sleep?It is Marine Megavertebrate Week right now, so why not take a look at one of the most Mega of the Megaverts – the grey whale (Eschrichtius robustus):
Do whales sleep? You may have heard that dolphins do – one hemisphere at the time, while swimming, and not for very long periods at a time. A combined Russian/US team of researchers published a study in 2000 – to my knowledge the best to date – on sleep-wake and activity patterns of the grey whale: Rest and activity states in a gray whale (pdf) by Lyamin, Manger, Mukhametov, Siegel and Shpak.

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Waking Experience Affects Sleep Need in Drosophila

Waking Experience Affects Sleep Need in DrosophilaThere is nothing easier than taking a bad paper – or a worse press release – and fisking it with gusto on a blog. If you happen also to know the author and keep him in contempt, the pleasure of destroying the article is even greater.
It is much, much harder to write (and to excite readers with) a blog post about an excellent paper published by your dear friends. But I’ll try to do this now anyway (after the cut).

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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.
[This is also the post included in ‘The Open Laboratory 2006’, the anthology of best science blogging]

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Sleep Schedules in Adolescents

Sleep Schedules in AdolescentsEarlier this year, during the National Sleep Awareness Week, I wrote a series of posts about the changes in sleep schedules in adolescents. Over the next 3-4 hours, I will repost them all, starting with this one from March 26, 2006. Also check my more recent posts on the subject here and here…

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Chronic vs. Acute Sleep Deprivation

In all animals, vertebrate and invertebrate alike, one of the defining features of sleep is the “rebound”, i.e., the making up for sleep debt after an acute sleep deprivation event. However, the problem of modern society is a chronic sleep loss in humans – when you loos a couple of hours of needed sleep every day.
Now, a team at Northwestern studied the effects of chronic sleep loss and, lo and behold – bad news! There is no rebound after chronic sleep deprivation.
Chronically sleep deprived? You can’t make up for lost sleep:

In the study, the researchers kept animals awake for 20 hours per day followed by a four-hour sleep opportunity, over five consecutive days. The team monitored brain wave and muscle activity patterns in order to precisely quantify sleep-wake patterns.
After the first day of sleep loss, animals compensated by increasing their intensity, or depth, of sleep, which is indicative of a homeostatic response. However, on the subsequent days of sleep loss, the animals failed to generate this compensatory response and did not sleep any more deeply or any longer than they did under non-sleep deprived conditions (baseline measurements). At the end of the study, the animals were given three full days to sleep as much as they wanted. Amazingly, they recovered virtually none of the sleep that was lost during the five-day sleep deprivation period.
The findings support what other scientists have discovered in recent experimental studies in humans. Chronic partial sleep loss of even two to three hours per night was found to have detrimental effects on the body, leading to impairments in cognitive performance, as well as cardiovascular, immune and endocrine functions. Sleep-restricted people also reported not feeling sleepy even though their performance on tasks declined.
The Northwestern team s results suggest that animals may undergo a change in their need for sleep, or in their sleep homeostat, in situations where normal sleep time is prohibited or where sleep could be detrimental for survival. An extreme but realistic example of this, says Turek, would be how animals respond to catastrophic environmental conditions, such as Hurricane Katrina. No matter how sleep deprived an animal or human may be, it would not be adaptive for the sleep homeostat to kick in and to make the animal fall sleep when it is in the midst of a flood or forest fire. Therefore, the body undergoes some change that allows it to counter its homeostatic need for sleep and to stay awake to avoid danger.
Turek and his team propose that this change in the sleep regulatory system is reflective of an allostatic response. In the short term, allostatic responses are adaptive, but when sustained on a chronic basis, such as in their study, an allostatic load will develop and lead to negative health outcomes. The allostatic load resulting from the accumulating sleep debt loops back to the sleep regulatory system itself and alters it.
Even though animals and humans may be able to adapt their sleep system to deal with repeated sleep restriction conditions, there could be negative consequences when this pattern is maintained over a long period of time, said Turek. This brings us back to the idea that repeated partial sleep restriction in humans has been linked to metabolic dysfunction and cardiovascular disease.

Sexual Activity Reported In Dreams Of Men And Women

I wonder if this new study was designed better than this one:

In a detailed study that served to investigate the actual nature and content of sexual dreams across a large sample of dream reports from men and women, approximately eight percent of everyday dream reports from both genders contain some form of sexual-related activity.
The percentage of women that reported such dreams can be due to the fact that either women actually experience more sexual dreams now than they did 40 years ago, or that they now feel more comfortable reporting such dreams due to changing social roles and attitudes, or both, according to new research.
The study, authored by Antonio Zadra, PhD, of the Universite de Montreal, focused on over 3,500 home dream reports collected from men and women. Sexual intercourse was the most common type of sexual dream content, followed by sexual propositions, kissing, fantasies and masturbation.
The study found that both men and women reported experiencing an orgasm in about four percent of their sexual dreams. Orgasms were described as being experienced by another dream character in four percent of the women’s sexual dreams, but in none of the male dream reports. Current or past partners were identified in 20 percent of women’s sexual dreams, compared to 14 percent for men, and public figures were twice as likely to be the object of women’s sexual dream content. Multiple sex partners were reported twice as frequently in men’s sexual dreams.
“Observed gender differences may be indicative of different waking needs, experiences, desires and attitudes with respect to sexuality,” said Zadra. “This is consistent with the continuity hypothesis of dreaming which postulates that the content of everyday dreams reflects the dreamer’s waking states and concerns — that is, that dream and waking thought contents are continuous.”
An abstract of this research was presented June 14 at SLEEP 2007, the 21st Annual Meeting of the Associated Professional Sleep Societies.

Sleep News

More stuff from SLEEP 2007, the 21st Annual Meeting of the Associated Professional Sleep Societies:
Sleep Deprivation Affects Eye-steering Coordination When Driving:

Driving a vehicle requires coordination of horizontal eye movements and steering. Recent research finds that even a single night of sleep deprivation can impact a person’s ability to coordinate eye movements with steering.

Extra Sleep Improves Athletes’ Performance:

Athletes who get an extra amount of sleep are more likely to improve their performance in a game, according to recent research.

Going To Bed Late May Affect The Health, Academic Performance Of College Students:

College students who go to bed late are more likely to have poor quality sleep, which may affect their mental health and academic performance, according to new research.

Safety And Well-being Of Medical Interns And Patients At Risk From Extended Duration Work Shifts:

Working an extended duration shift can pose a risk to not only the safety and well-being of medical interns, but also to that of their patients, according to a recent research.

Sleep-related Breathing Disorder Common Among Aggressive, Bullying Schoolchildren:

Aggressive behavior and bullying, common among schoolchildren, are likely to have multiple causes, one of which may be an undiagnosed sleep-related breathing disorder (SRBD), according to recent research.

Late Weekend Sleep Among Teens May Lead To Poor Academic Performance:

Teenagers who stay up late on school nights and make up for it by sleeping late on weekends are more likely to perform poorly in the classroom. This is because, on weekends, they are waking up at a time that is later than their internal body clock expects. The fact that their clock must get used to a new routine may affect their ability to be awake early for school at the beginning of the week when they revert back to their old routine, according to new research.

Sleep Deprivation Can Lead To Smoking, Drinking:

Sleep loss or disturbed sleep can heighten the risk for adolescents to take up smoking and drinking, two habits that may prove to be detrimental to their health, according to recent research.

Children’s Brain Responses Predict Impact Of Sleep Loss On Attention:

The brain responses of those children who don’t get enough sleep can accurately predict the impact sleep loss has on their ability to pay attention during the course of a day, according to a recent research.

Snoring Children: Poor Sleep Hygiene In Children Associated With Behavioral Problems:

A snoring child’s poor sleep hygiene habits can have a negative influence on his or her daytime behavior, according to a new study.

Chronic Sleep Restriction Negatively Affects Cardiac Activity:

Chronic sleep restriction has a negative effect on a person’s cardiac activity, which may elevate the risk of cardiovascular disease and mortality, according to a research abstract presented at SLEEP 2007, the 21st Annual Meeting of the Associated Professional Sleep Societies (APSS).

Sleep Deprivation Is Common Among Members Of The US Marine Corps:

Members of the U.S. Marine Corps (USMC) experience combined stressors, including physical exertion and the threat of enemy fire. A research abstract that presentedJune 13 at SLEEP 2007, the 21st Annual Meeting of the Associated Professional Sleep Societies, finds that sleep deprivation, which can result in fatigue, is another factor that can impair troops’ vigilance and decision-making with potentially dangerous consequences.

Catastrophic Events Can Affect A Person’s Sleep:

A significant disruption of day-to-day life can take place in those areas affected by a natural disaster. One of the more recent disasters occurred when Hurricane Katrina struck the Gulf Coast in late August 2005, causing loss of lives, extensive damage, and the evacuation of hundreds of thousands of residents. Disasters such as Hurricane Katrina are more likely to affect the quality and the quantity of a person’s sleep, according to recent research.


Sleep News

Children With Sleep Disorder Symptoms Are More Likely To Have Trouble Academically:

Students with symptoms of sleep disorders are more likely to receive bad grades in classes such as math, reading and writing than peers without symptoms of sleep disorders, according to recent research.

Slow Wave Activity During Sleep Is Lower In African-Americans Than Caucasians:

Slow wave activity (SWA), a stable trait dependent marker of the intensity of non-rapid eye movement (NREM) sleep, is lower in young healthy African-Americans compared to Caucasians who were matched for age, gender and body weight, according to recent research.

Sleep Disorders Highly Prevalent Among Police Officers:

A sampling of police officers shows a high incidence of sleep disorders among the members of this profession. Sleep disorders are common, costly and treatable, but often remain undiagnosed and untreated. Unrecognized sleep disorders adversely affect personal health and may lead to chronic sleep loss, which, in turn, increases the risk of accidents and injuries. These problems are exacerbated in shift workers such as police officers, who may experience chronic sleep loss due to their schedules. A sampling of police officers shows a high incidence of sleep disorders among the members of this profession, according to recent research.

Sleep Restriction Affects Children’s Speech:

Research examining the impact of sleep in school-age children suggests that even mild sleep loss produces marked deficits in their cognitive development and functioning. Sleep restriction can alter children’s initial stages of speech perception, which could contribute to disruptions in cognitive and linguistic functioning — skills necessary for reading and language development and comprehension, according to recent research.

Link Between Common Sleep Disorder And High Blood Pressure Discovered:

An international team of researchers, led by Emory University clinician scientists, has found evidence that people suffering from moderate to severe cases of restless legs syndrome (RLS) are at significantly increased risk for developing hypertension.

Patient Care Improves When Medical Residents Work Fewer Hours:

When medical residents work shorter hours, fewer patients are transferred to intensive care and there are not as many interventions by pharmacists to avoid errors in medication, according to a Yale School of Medicine study in Annals of Internal Medicine.

Sleep Problems May Affect A Person’s Diet:

Sleep problems can influence a person’s diet. Those who don’t get enough sleep are less likely to cook their own meals and, instead, opt to eat fast food. It is the lack of nutritional value of this restaurant-prepared food that may cause health problems for these people in the long-run, according to new research.

CPAP Improves Sleep In Patients With Alzheimer’s Disease, Sleep-related Breathing Disorder:

Patients with both Alzheimer disease and a sleep-related breathing disorder (SRBD) experience disrupted sleep, resulting in increased nocturnal awakenings and a decreased percentage of REM sleep. However, in another example of the effectiveness of continuous positive airway pressure (CPAP), CPAP has been found to reduce the amount of time spent awake during the night, increase the time spent in deeper levels of sleep, and improve oxygenation, according to a recent study.

Sleep News

Sleep Deprivation Affects Airport Baggage Screeners’ Ability To Detect Rare Targets:

A lack of sleep may affect the performance of airport employees, which can, in turn, compromise the safety of airline passengers. Sleep deprivation can impair the ability of airport baggage screeners to visually search for and detect infrequently occurring or low prevalence targets that may ultimately pose a threat to an airline and its passengers, according to new research.

Night Shift Nurses More Likely To Have Poor Sleep Habits:

Nurses who work the night shift are more likely to have poor sleep habits, a practice that can increase the likelihood of committing serious errors that can put the safety of themselves as well as their patients at risk, according to recent research.
Arlene Johnson, of the University of Alabama at Birmingham, surveyed 289 licensed nurses while they were working on the night shift in the hospital setting, and classified the subjects as either sleep deprived or not sleep deprived. The results showed that 56 percent of the sample was sleep deprived.

Sleep News

Wide Range Of Sleep-related Disorders Associated With Abnormal Sexual Behaviors, Experiences:

A paper published in the June 1st issue of the journal SLEEP is the first literature review and formal classification of a wide range of documented sleep-related disorders associated with abnormal sexual behaviors and experiences. These abnormal sexual behaviors, which emerge during sleep, are referred to as “sleepsex” or “sexsomnia”.

See also this, this and this.
Why Patients With Obstructive Sleep Apnea Are At Higher Risk For Cardiovascular Disease:

Researchers have found that patients with obstructive sleep apnea (OSA) have higher levels of a type of dead cells (apoptotic cells) from the lining (endothelium) of their blood vessels circulating in their bloodstream than people who do not have OSA. The finding may help explain why those with OSA are at higher risk for cardiovascular disease (CVD).

Sleep Genes are not the same as ‘Genes for sleep’

Back in the late 1990s, when people first started using various differential screens, etc. looking for elusive “genes for sleep”, I wrote in my written prelims (and reprinted it on my blog several years later):

Now the sleep researchers are jumping on the bandwagon of molecular techniques. They are screening for differences in gene expression between sleeping and awake humans (or rats or mice), searching quite openly for the “genes for sleep”. Every time they “fish out” a gene, it turns out to be Protein kinase A, a dopamine receptor, or something similar with a general function in the brain. Don’t they understand that sleep (like hibernation) is an emergent property of a multicellular brain? Unlike in the clock field, a single neuron does not carry the function – it does not sleep. Only whole (or halves of) brains can be asleep or awake. The sleep “mechanism” is not a molecular mechanism but a result of a particular pattern of neural connectivity and activity.

And, lo an behold, all the genes that affect sleep (the duration or quality of it, not timing which is guided by the circadian clock), turned out to be those “maintanance” molecules, involved in general, day-to-day activity of neurons. Most geneticists have since moved away from such a simplistic, bean-bag genetics notion of sleep and started studying sleep from a much more integrative perspective. But some persist. The newest discovery of a “sleep-gene” is just like what I predicted, a general-maintanance molecule – an ion channel:
Second Sleep Gene Identified:

A gene that controls the flow of potassium into cells is required to maintain normal sleep in fruit flies, according to researchers at the University of Wisconsin School of Medicine and Public Health (SMPH). Hyperkinetic (Hk) is the second gene identified by the SMPH group to have a profound effect on sleep in flies.
The finding supports growing evidence that potassium channels–found in humans and fruit flies alike–play a critical role in generating sleep.
“Without potassium channels, you don’t get slow waves, the oscillations shown by groups of neurons across the brain that are the hallmark of deep sleep,” says Chiara Cirelli, SMPH psychiatry professor and senior author on the latest study, which appeared in the May 16, 2007, Journal of Neuroscience.

Very cool and important for the advancement of our understanding of sleep, but surely not a “gene for sleep”.

The unnecessary heroics (like injecting yourself with toxins)

If you watch Tony Wright on his webcam every single millisecond of his experiment, you will likely have some interesting experiences yourself, apart from seeing how sleep deprivation messes with his mind. And his health.