Researchers have found fundamental differences between the brains of people who prefer to rise and greet the dawn each day, and those who don’t mind seeing a sunrise, but only if it’s at the end of a long night. A new study used brain scans and alertness tests to probe the brains of early birds and night owls, and found that people tend to favor mornings or nights based at least in part on how they react to a kind of competition in the brain [National Geographic News].
Two factors control our bedtime. The first is hardwired: A master clock in the brain regulates a so-called circadian rhythm, which synchronizes activity patterns to the 24-hour day. Some people’s clocks tell them to go to bed at 9 p.m., others’ at 3 a.m…. The second factor–called sleep pressure–depends not on time of day but simply on how long someone has been awake already [ScienceNOW Daily News]. Sleep pressure builds up as hours of wakefulness increase. The new study, published in Science, suggests that early birds are more susceptible to sleep pressure, giving night owls the advantage in stamina.
In a sleep lab, the researchers studied people with extreme bedtimes, or chronotypes, both early and late. The larks in the study typically woke up between 4 a.m. and 5:30 a.m. and went to bed by 9 p.m. The night owls, or evening chronotypes, left to their own devices would go to bed at 3 a.m. or 4 a.m. and rise at noon [Science News]. All the test subjects maintained their preferred sleep schedules to avoid interfering with their circadian rhythms, and took tests measuring their alertness 1.5 hours after waking, and again 10.5 hours after waking. In the earlier test researchers saw no difference between the two groups’ performances, but in the later test the night owls performed better than the early birds, and also topped their own prior test results.
FMRI brain scans told the rest of the tale. In the night owls, increased activity was seen in two parts of the brain at 10.5 hours — the suprachiasmatic nucleus area and the locus coeruleus — that are involved in regulating the circadian signal. Essentially, the circadian signal was winning out over the pressure to sleep. In the early birds, on the other hand, “the sleep pressure prevents the expression of the circadian signal,” so those individuals were less able to keep their attention focused [LiveScience], says study coauthor Philippe Peigneux. The study is the first to show that circadian rhythms and sleep pressure interact to govern behavior; researchers previously believed that the two systems operated independently.
But while night owls seem to handle sleep pressure better, the late-to-bed strategy might backfire outside the lab…. “Morning types may be at an advantage, because their schedule is fitting better with the usual work schedule of the society,” [Peigneux] said. “It may represent a problem for evening types obliged to wake up early while having difficulties going to bed in the evening, eventually leading to a sleep debt” [National Geographic News].
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Images: flickr / Eric Kilby and MyAngelG
April 24th, 2009 at 1:04 pm
Interesting though I beleive that they should have included the third schedule of the day, go to bed at 11 a.m. or noon and rise at 7pm or so.
April 24th, 2009 at 5:13 pm
As a nightowl myself, I am happy to know that I am outperforming my wussie “morning person” friends!
April 25th, 2009 at 5:05 pm
It’s good to know studies are going on relating to this subject because I have to struggle really hard to keep normal working hours, but when everyone else buggers off home in the afternoon I’m raring to go because I’m just starting to reach my most efficient time. I really suffer from the lack of sleep though. I cannot get to sleep early unless something has made me really tired. I also often stay awake overnight to force myself to sleep the following night, but my body clock seems to prefer sleeping through the morning rather than through the night. Unfortunately there don’t seem to be any decent jobs around for night owls, so we are forced to suffer the hours of the early birds.Hmmmm, I wonder if this could fall under the discrimination act…
April 26th, 2009 at 2:09 am
My happiest schedule was 1:00 p.m. to 9:00 p.m., but those days are over (sigh). Even in the city that never sleeps, most of the jobs are 9 to 5. Carl, when you get the class action suit ready let me know!
April 26th, 2009 at 2:27 am
Most irritating of all is to constantly be told that you’re just lazy, and that there’s no such thing as early birds or night owls. The majority of people (early birds) remain convinced that those who struggle with getting up in the morning have misaligned sleep schedules.
I’ve always been able to work long hours after noontime without breaks. My coworkers have their regular lunch hours, but I’m not hungry for lunch until about 4pm.
Another fascinating article is on the National Geographic website…google ‘early birds and night owls’. It describes how samples of skin cells taken from people in a recent study will fluoresce and pulse under the microscope, and that the rate of the pulse will identify each group separately.
April 26th, 2009 at 9:33 pm
Ryan, you don’t learn about the body/mind by studying the norm, you learn by studying the extremes, the dysfunctional.
April 27th, 2009 at 12:13 pm
Before the party-all-night Dionysians get too excited, wait for the other shoe to drop: a study will be reported clearly showing that culture and society does in fact benefit from all the early birds out there rather than the night owls.
Of course, I believe the natural historians will tell us that mammals started out actually being nocturnal animals by necessity.
But as the eons passed, there was something called “evolution,” and apparently it was such that we bipedal creatures came out from the night and into the daylight. If evolution is truly a progression, that is, it represents an improvement, and this improvement is in the intelligence of a sapient species, then I propose that the advancement of humankind is attributable more to the early birds and less to the night owls.
I admit though that I say this as a person unable to sleep at all when the first dawn of light fills my bedroom.
April 30th, 2009 at 9:54 am
I would fail the part about doing well an hour and a half after waking; it takes me at least 5 hours to get to normal functioning and I crash about 2 hours after rising; and my functioning keeps rising until about 1-2 hours after going to bed. I suspect that’s why my PSAT (taken several hours after waking) was 75 (anticipating an SAT of 800) and my actual SAT taken an hour after waking was 712.
And re what homo was before evolution; they were more likely to be functional at dawn and dusk when they could see and when the savanna heat was not over-powering their relatively hairy bodies.
May 22nd, 2009 at 2:42 pm
RE: SMH
Your conclusions are highly subjective, in fact you admit in the last sentence that you are not an objective party. A study may indeed find that society benefits from it’s present schedule; that’s because our entire infrastructure is built around the 9 to 5 workday. One would have to experiment with several large groups of people over a long period of time to obtain any useful data beyond pure speculation.
I’d design the experiment as such:
Gather a group of 4000 subjects. Arrange them into four groups.
Group A should be a group of self professed ‘larks’ and be put on a schedule that revolves around being an early riser.
Group B should be a group of self professed ‘night owls’ and likewise should have a schedule that accomodates them.
Group C should be a mixture of both owls and larks. They might be put on a rotating schedule which periodically switches.
Group D is the control and should comprise a random group of subjects on the orthodox 9 to 5 schedule.
Obviously the experiment would have to screen the subjects beforehand and arrange a battery of tests (such as IQ, health, sensory, etc.) to determine that all groups have an equal distribution of personality types so as to not skew the results. Once the group was assembled they should be put into a controlled environment and monitored for at least a year, preferably more. Data would be collectly daily and entered into a collective pool for each group. At the end of the test it should be obivious whether any group consistently outperformed the other (of course they would not know about the other groups as not to instill competition). On the other hand you might see that there is no difference or that the control is more consistent.
The point is that we need some solid data and a very large group of diverse subjects to make any real conclusions.
By the way, I happen to be a night owl.
June 1st, 2009 at 11:17 pm
I have been redeemed! I am a definitely an owl and not a dove! When I do get to work around 9:00 am, my engines are steamed and I am ready to get right into my job; thank goodness because the minute I do get there, everyone else is finally awake. I put in long days, but I am on the go from the time I get there until the time I leave. I am focused and extremely productive. My biggest pet peeve in the workplace is the worker that makes the comment, (as they are heading for the door at the end of their work day at 3:00 in the afternoon…)”Well I’ve been here since 6:30″!! That drives me crazy.. SO WHAT!!! What that individual did since 6:30 is what is most important, not the time they physically arrived in the building. Early birds have always seemed to get the admiration for getting up early and getting after the day… blah blah blah,. I once had this fear of being caught sleeping after 7:30 in the morning on a weekend… whatever. I love my sleep and when I am awake, watch out because I am a powerhouse and I don’t stop until late at night. I would be confident to say that I probably do more in the first hour of my day than allot of folks accomplish in their entire day.
July 9th, 2009 at 3:40 pm
I’d like to add to what Ryan said, people like us are really overlooked and we don’t even have a name. I’m one of those people whose natural sleep time is between 11 AM and 2 PM and natural waking time is between 7 PM and 9 PM. What are we called?
October 20th, 2009 at 2:07 am
Bi-peds came out during day when they discovered how to farm for their food supply. With technology and the global economy, business are redefining the traditional work schedules .
This article proves our individual differences are defined by complex functions of the brain and behavior patterns are driven by unique biological structures of every human beings. How many Night Owls are living their life without reaching their full potential because they are not given the opportunity to work when their body is primed for peak performance.
December 11th, 2009 at 5:17 am
How is the circadian rhythm of a person defined? How do you know for sure what is each person’s biological rhythm? Aren’t there multiple factors, such as social pressure, which affect to the rhythm? Maybe a person’s practical rhythm is a compromise between all the different factors?
I would like to know circadian rhythm statistics of the population. Is there any? Where I could see one? How many different types there are? Are there different rhythms continuously around the clock or are there only certain discrete types of rhythms? What is the most active time of the day to each and what is the best time to sleep to each?
As a “night owl” I also would like to know some guides on how to best adapt to this society without suffering too much of the “wrong” rhythm of it. The “night owls” should be understood better instead of judging them.