Tag Archives: circadian rhythm

If you don’t align your sleeping patterns to your body clock, you risk depression, lower wellbeing

If you like to skip on sleep, we have some bad news: a new study reports that people whose sleeping patterns go against their natural body clock are more likely to be depressed, and experience lower levels of wellbeing.

Image via Pixabay.

Early bird gets the worm and all that, but we now have evidence to show that some people really are naturally early risers. Even worse, going against this, or being a night owl by nature, seems to promote issues such as depression and lower perceived quality of life. But you can rest easy, there’s nothing wrong with you. Most likely, these effects are caused by the way our societies are ordered, as they are generally tailored more for early risers, through the standard 9-5 working pattern.

The right time for sleep

The research was built on previous work that mapped 351 genes linked to being either an early riser or a night owl. A statistical process known as Mendelian Randomisation was employed to see whether these genes had a causal association with seven mental health and wellbeing outcomes (major depression was one of these seven). Data for the study was supplied from the UK Biobank’s biomedical database and research resource and pertained to over 450,000 UK adults.

Apart from genetic information, participants also supplied information regarding their sleeping habits (i.e. whether they were a morning or evening person) through a questionnaire.

Alongside this data, the authors also developed a new indicator of “social jetlag”, a measurement of the variations in sleeping patterns one experiences between workdays and free days. This was measured in around 85,000 UK Biobank participants (for whom sleep data was available) via wrist-worn activity monitors.

The first important finding of the study was that participants whose natural and actual sleeping patterns were more misaligned were more likely to report depression, anxiety, and lower wellbeing.

“We found that people who were misaligned from their natural body clock were more likely to report depression, anxiety, and have lower wellbeing. We also found the most robust evidence yet that being a morning person is protective of depression and improves wellbeing,” says lead author Jessica O’Loughlin, of the University of Exeter.

“We think this could be explained by the fact that the demands of society mean night owls are more likely to defy their natural body clocks, by having to wake up early for work.”

Morning people had the highest likelihood of their sleeping patterns being aligned with their natural body clock. When looking at shift workers alone, the team found that being a morning person doesn’t seem to protect them from depression. This is likely indicative that morning people who work shifts don’t get any benefits from their natural sleeping patterns, but this remained inconclusive overall.

“The COVID-19 pandemic has introduced a new flexibility in working patterns for many people. Our research indicates that aligning working schedules to an individual’s natural body clock may improve mental health and wellbeing in night owls,” said senior author Dr Jessica Tyrrell, of the University of Exeter.

The paper “Using Mendelian Randomization methods to understand whether diurnal preference is causally related to mental health” has been published in the journal Molecular Psychiatry.

Turns out, some plants are also night owls

Just like people, plants also have diurnal variations, and some aren’t really fans of mornings.

Is it morning already? Image credits: Markus Spiske.

As we’ve all undoubtedly seen, some people we know are morning persons, while others, well, are not. This circadian clock is directed by a molecular metronome which guides our organisms through day and night like an internal cockadoodledoo that gets us up in the morning. It’s not just a morning or afternoon preference, many bodily processes are directed by this rhythm.

Researchers have known for a time that plants also seem to have this type of rhythm, and a team of researchers at the Earlham Institute and John Innes Centre in Norwich set out to explore what makes plants’ internal clocks tick, especially as understanding plant rhythms could enable farmers to optimize what they grow.

“A plant’s overall health is heavily influenced by how closely its circadian clock is synchronised to the length of each day and the passing of seasons. An accurate body clock can give it an edge over competitors, predators and pathogens,” says Dr. Hannah Rees, a postdoctoral researcher at the Earlham Institute and author of the paper.

The team examined Swedish Arabidopsis plants (Arabidopsis is the botanical version of the fruit fly — routinely used in experiments) to identify which genes direct these circadian shifts and how they influence plant activity. Swedish plants were also a good testing ground, Rees adds.

“We were interested to see how plant circadian clocks would be affected in Sweden; a country that experiences extreme variations in daylight hours and climate. Understanding the genetics behind body clock variation and adaptation could help us breed more climate-resilient crops in other regions.”

The team studied the genes of 191 varieties of Arabidopsis gathered from around Sweden, looking for minute genetic differences that could be tied to circadian function. Ultimately, their analysis found that a single DNA base-pair in one gene (COR28) made plants flower later and for a longer period. In other words, COR28 seems to direct the plants’ circadian rhythm.

“It’s amazing that just one base-pair change within the sequence of a single gene can influence how quickly the clock ticks,” explained Dr. Rees.

There was a difference of over 10 hours between the plants that ‘woke up’ and started activity earliest and the ones that started latest. It’s almost as if plants were working different shifts, researchers say.

Now, the team is looking at how what they’ve learned could be applied for plants of economic importance.

“Our findings highlight some interesting genes that might present targets for crop breeders, and provide a platform for future research. Our delayed fluorescence imaging system can be used on any green photosynthetic material, making it applicable to a wide range of plants. The next step will be to apply these findings to key agricultural crops, including brassicas and wheat.”

The study was published in the journal Plants, Cell & Environment.

Credit: Pixabay.

Scientists identify genes that might make you a morning person (or night owl)

Credit: Pixabay.

Credit: MaxPixel.

Researchers in the UK and USA have shed new light on the internal body clocks that operate our biological schedules. The body clock, also known as the circadian rhythm, is responsible for releasing molecules that signal the body that it is time sleep in the evening and wake up in the morning. New research suggests that some genes may predispose a person to a be morning person — or conversely a night owl. The authors also identified associations between waking up early and greater psychological well-being and a lower risk of mental disorders, such as schizophrenia and depression.

The study involved 250,000 American participants, whose genomes were analyzed by private company 23andMe, and 450,000 participants who were part of the UK Biobank study. All participants had previously completed a questionnaire that assessed whether they’re a “morning person” or an “evening person”. Their self-reported sleep-wake routines were confirmed with wrist-worn activity trackers that were used by 85,000 of the UK Biobank participants.

By looking at which genes were common among people who shared sleeping patterns, the researchers found hundreds of new genetic loci (regions), increasing the tally from 24 previously known loci to 351. These include genes that are known to play an important role in our body clocks, as well as genes expressed in the brain and in the retinal tissue in the eye.

“This study highlights a large number of genes which can be studied in more detail to work out how different people can have different body clocks. The large number of people in our study means we have provided the strongest evidence to date that ‘night owls’ are at higher risk of mental health problems, such as schizophrenia and lower mental well-being, although further studies are needed to fully understand this link,” Professor Mike Weedon, of the University of Exeter Medical School, who led the research, said in a statement.

The authors say that the retinal tissue connection may explain how the circadian rhythm resets each day in order to align itself with a 24-hour cycle. We use our eyes to make sense of our environment and navigate our surroundings, but sight isn’t all that they do. A previous study showed that photosensitive retinal ganglion cells present in the retina — the most complex part of the eye — act as sort of light meter, informing the body what time of the day it is. When humans aren’t exposed to light our circadian rhythms last longer than 24 hours leading to all sort of health problems.

According to the present work published in Nature, the newly identified gene variants could shift a person’s natural waking time by up to 25 minutes. These genetic regions influence the timing of sleep, but not its quality or duration.

However, lifestyle factors such diet, exposure to artificial light, and our jobs seem to play a more important role than genes. The fact remains, though, that if some people are truly predisposed to be night owls, then every little thing can add up to produce significant effects. And all of this could be important since the authors claim that people who stay up at night are more predisposed to mental health conditions such as schizophrenia and depression.

“We know that there are links between how the body clock functions and our health and wellbeing but, to date, we have understood little about the part genetics plays. Now, with the help of publicly funded datasets like UK Biobank, researchers are able to study on an unprecedented scale, the interplay between the genetics of the body clock and the risk of mental health conditions such as schizophrenia and depression. This study provides valuable new insights which we hope will lead to more effective interventions for those most at risk,” Dr. Rachael Panizzo, Programme Manager for Mental Health and Addiction at the Medical Research Council, said in a statement.

“By understanding the genetics of sleep and activity timing in the general population, we also gain insights into potential avenues of therapy for individuals with more extreme conditions, such as those with advanced or delayed circadian rhythm disorders,” Co-lead author Dr. Jacqueline M Lane, of the Massachusetts General Hospital Department of Anesthesia, added.

Nobel Prize for Medicine awarded for circadian rhythm research

Jeffrey C. Hall, Michael Rosbash and Michael W. Young have been awarded the 2017 Nobel Prize in physiology or medicine for their work on molecular mechanisms controlling circadian systems.

It’s my favorite kind of research: sleep research. Circadian rhythms control when we’re at our best, our worst, and when we sleep. For everything we do that messes up this rhythm, we pay a price. Fly to a different time zone? Jet lag. Midnight snack? Mess up your metabolism. All nighter? Feel like crap the next day. The circadian rhythm affects everything from energy levels to metabolism, mood, and even fertility. But how is our body so good at keeping time, and how do all the individual parts of our body keep the same rhythm?

“The circadian system has its tentacles around everything,” Rosbash said in an interview with the HMI Bulletin in 2014. “It’s ticking away in almost every tissue in the human body.” It’s also in plants, including major food crops, the article noted, and appears to be tied to “disease susceptibility, growth rate, and fruit size.”

This is where the research steps in. The field of science emerged in the 1970s when geneticist Seymour Benzer and his student Ron Konopka managed to track down the genes that encode biological timing in fruit flies. Hall, Rosbash and Young also studied fruit flies, using them as a model organism. They showed that many genetical abnormalities and serious diseases are correlated with irregular circadian rhythms. A genetic mutation has already been found in some people who have a chronic sleeping problem, Young said. Among others, Alzheimer’s, depression, attention-deficit/hyperactivity disorder (ADHD), heart disease, obesity and diabetes and other metabolic issues are all included.

They suspected that because the effects are virtually ubiquitous inside the body, the brain likely uses one element to keep track of time. It wasn’t easy, but they managed to isolate a gene that is responsible for a protein that accumulates in the night but is degraded in the day. This was one of the key cogs in the mechanism, and paved the way for their later groundbreaking research.

“Before you’ve got the genes, everything is a black box,” Michael Hastings of the MRC Laboratory of Molecular Biology in Cambridge, England, said. “Once you’ve got the genes, everything is possible.”

At the moment, the discovery didn’t generate the excitement it probably deserved. Even though researchers explained that it could one day enable us to understand sleep and the circadian rhythm, it just didn’t cause a big stir. It took years and years before the doors their research opened became obvious.

Hall, who is now retired, said he got the notice call at 5 a.m. — but due to age-related changes in his own circadian rhythms, he was already awake. He added that he would love to reinvest some of the money into his research… but unfortunately, he retired from that years ago.Here’s his awesome and unconventional speech:


Rosbash, a 73-year-old professor at Brandeis, talked more about their research. He told the AP that he and his two colleagues worked to understand “the watch … that keeps time in our brains.”

“You recognize circadian rhythms by the fact that you get sleepy at 10 or 11 at night, you wake up automatically at 7 in the morning, you have a dip in your alertness in the midday, maybe at 3 or 4 in the afternoon when you need a cup of coffee, so that is the clock,” he explained.

“The fact that you go to the bathroom at a particular time of day, the fact if you travel over multiple time zones your body is screwed up for several days until you readjust — all that is a manifestation of your circadian clock.”

The Nobel Prize in Physics was also awarded earlier today. I won’t give any spoilers, but the gravity of the situation should not be underestimated.

Planet Earth.

Delaying meals can alter the body clock and solve some of that jet lag

Flying in another time zone or working graveyard shifts messes up with our circadian rhythms and ultimately triggers a slew of health problems. Research suggests that one in five people living in Western countries who work at odd hours are putting their lives at risk since their schedule has been linked to obesity, diabetes, heart disease, even cancer. Now, a new study suggests delaying meals can delay metabolic functions governed by the biological clock, too. The work suggests that changing meal times, coupled with light exposure, can help synchronize the ‘clock’ and reduce health problems.

Planet Earth.

Credit: Pixabay.

The notion that our bodies’ biology runs in cycles known as circadian rhythms — also known as sleep/wake cycle or body clock — is becoming more and more established. This complex timekeeping system is controlled by an area of the brain that responds to light, which is why humans are most alert while the sun is shining and are ready to sleep when it’s dark outside.

Humans don’t have a single body clock but a complex network of clocks — as many as there are cells in the body. In mammals, all of these ‘clocks’ are synched with a master clock which beats by the rhythm set in a region of the brain called the suprachiasmatic nuclei (SCN) but also with peripheral clocks found elsewhere, like in various other organs.

It’s the circadian rhythm that ultimately influences sleep-wake cycles, hormone release, body temperature and other important bodily functions. That’s why disrupting this biological clock can come at a hefty cost to our health. Sometimes, though, such situations are inevitable, like in a work setting — what to do?

Previous research has established that there’s a link between nutrition and the circadian rhythm but it’s only recently that this connection has been traced out in broader detail. Researchers at the University of Surrey in the UK recruited ten healthy volunteers who were fed three meals a day at exactly the same times every day for five days. After this initial round, the researchers delayed each meal time by five hours on the following six days. Each daily meal was identical in caloric and macronutrient content and at the end of the six days, the volunteers had to stay awake for 37 hours. They had small, identical snacks every hour for sustenance and dim lighting, in order to measure any change in their circadian rhythms.

These shifts caused a change in the cycle of blood sugar levels.

“A 5-hour delay in meal times causes a 5-hour delay in our internal blood sugar rhythms,” said Jonathan Johnston, one of the authors of the new study published in Current Biology. “We think this is due to changes in clocks in our metabolic tissues, but not the ‘master’ clock in the brain.”

Later, the authors found that the way a certain clock gene released instructions in white fat tissue was delayed after the shift in meal times. Seeing how the ‘master clock’ wasn’t affected, the researchers reckon the delayed meals caused changes in the peripheral clocks without affecting the master clock.

Most jet lag and shift work therapies revolve around controlling light exposure but this sort of intervention seems to work on the master clock only. Changing meals, on the other hand, can help the peripheral clocks come up to speed as well, thus reducing desynchronisation of the body’s clocks.

Keep in mind, though, that this was a small study which needs more validation before we can draw sound conclusions. It does suggest, however, that delaying breakfast for a couple of hours if you flew from London to Moscow can help. Nothing seems to beat a whole week camping under the stars, though.

Fridge raid

Have dinner earlier if you’re trying to lose weight, study says

A preliminary human trial has shown that changing your eating schedule could help with weight loss. The results show it can help reduce swings in appetite and change fat and carbohydrate burning patterns in the body.

Fridge raid

Image credits bark / Flickr.

It’s an old wives’ tale that might have actually gotten it right. The first human trial or early time-restricted feeding (eTRF) has shown that the practice could help you get rid of the holiday belly. It’s a pretty straightforward practice: eat your last meal by mid-afternoon and then fast until breakfast the next morning.

Which is bad news, since I can’t remember having a single breakfast with ‘a.m.’ still showing on the clock since starting college.

“Eating only during a much smaller window of time than people are typically used to may help with weight loss,” said Courtney Peterson, Ph.D., an associate professor in the Department of Nutrition Sciences at UAB.

“We found that eating between 8 a.m. and 2 p.m. followed by an 18-hour daily fast kept appetite levels more even throughout the day, in comparison to eating between 8 a.m. and 8 p.m., which is what the average American does.”


All you have to do is eat a very early dinner, or even skip it altogether. Your body works by following has several internal timetables, called circadian rhythms. They power-up and shut down systems throughout the body, and several key metabolic processes are most efficient in the morning. Eating in tandem with these processes means your body is better prepared to absorb and process the nutrients in your food.

For the study, Peterson and her team followed 11 men and women with excess weight two four-day periods. First, were asked to eat between 8 a.m. and 2 p.m., then between 8 a.m. and 8 p.m. They noted the impact of eTRF on the numbers of calories burned, the amount of fat burned, and appetite levels. The participants followed both schedules, ate the same number of calories during both, and were supervised throughout the testing period.

The team reports that although eTRF did not affect the participants’ calorie intake or how many they burned off, it reduced hunger swings throughout the day and increased levels of fat being burned during several hours at night. They also report that the practice improved metabolic flexibility — the body’s ability to switch between burning carbs and fats.


However, keep in mind that this is still very early research and definitively not conclusive on its own. It’s still not clear if eTRF helps with long-term weight loss or brings other health benefits to the table. Peterson says that a larger, more comprehensive study is required to confirm or contradict the findings.

ETRF has previously been proven effective in animals, helping lab rats burn off more fat and decreasing the onset of chronic diseases. This trial shows that humans too could maybe benefit from the practice.

The paper was presented at The Obesity Society Annual Meeting at Obesity Week 2016 in New Orleans, Louisiana.


Kids everywhere, rejoyce – science says you should get those “5 more minutes, mom!”

A recent study performed by researchers working at the University of Oxford, Harvard Medical School and the University of Nevada suggests that the current school and university start times have a damaging effect on the learning and health of students.

Later starting hours for school and college could lead to better academic results and better overall health for students. It would also be awesome.
Image via xplodemag

Adolescents today face a widespread chronic health problem: sleep deprivation. Although society often views sleep as a luxury that ambitious or active people cannot afford, research shows that getting enough sleep is a biological necessity, as important to good health as eating well or exercising.

Drawing on the latest research in the field of pillow-and-blanket face times, the authors calculated the best time for students to attend courses, sorted by age.

Results show start times should be 08:30 or later at age 10; 10:00 or later at 16; and 11:00 or later at 18. Adopting these start times would protect attendees from short sleep duration, chronic sleep deprivation and the health complications associated with them.

The findings tap into recent insight regarding circadian rhythms -also know as “the body clock“, the mechanism that makes us jet-lagged – and of the genes associated with governing this daily cycle every 24 hours. It tells our body when it’s nappy time and when it’s wakey time, makes us sleepy at night and keeps us pumped up during the day.

Teens are among those least likely to get enough sleep; while they need on average 9 and a 1/4 hours of sleep per night for optimal performance, health and brain development, teens average fewer than 7 hours per school night by the end of high school, and most report feeling tired during the day, acording to Wolfson & Carskadon, 1998.

The main culprits are poor teen sleep habits that do not allow for enough hours of quality sleep; hectic schedules with afterschool activities and jobs, homework hours and family obligations; and a clash between societal demands and biological changes that put most teens on a later sleep-wake clock; during adolescence, our inherent circadian rhythms start to de-synchronize with those imposed by the typical working day – early bird and all that.

Circadian rhythms determine our optimum hours of work and concentration, and they shift almost 3 hours later during this period. These genetic changes in sleeping patterns were used to determine start times that are designed to optimize learning and health.

Adopting later starting times for school and college would help improve both academic performance and students’ health, according to the study. It’s not just wishful teen thinking, either: the US Department of Health has recently published an article in favor of changing the start times for Middle and High Schools.

Corresponding author Paul Kelley (Honorary Clinical Research Associate, Sleep and Circadian Neuroscience Institute, University of Oxford) will be presenting “Time: the key to really understanding our lives” at the British Science Festival on Tuesday 8 September.

circadian rhythm body clock

There’s a reset trigger for your biological clock – bye, bye jet lag, insomnia and exhaustion

While humans have invented a convention called time keeping to make society work, our bodies themselves also have a sort of clock called an internal biologic clock or circadian rhythm. When met by daylight, hormones are released that keep us awake and alert, while darkness releases different hormones that puts us to sleep. Canadian researchers have now found the molecular switch that resets and synchronizes the circadian clock. A drug that tweaks this switch could thus be made that regulates the internal clock, something travelers and night owls might find particularly useful.

Setting the clock

circadian rhythm body clock

Image: Shutterstock

Nahum Sonenberg, a biochemist from McGill University in Quebec, and colleagues found light resets the internal clock by triggering phosphate to combine with a protein found in the brain called eIF4E. This process is called  phosphorylation. The researchers engineered mice whose eIF4E couldn’t be phosphorylated, then tuned the lighting inside a cage from a 12-hour cycle to a 10.5-hour cycle, a relatively minor adjustment. Control group mice which weren’t engineered adapted quite quickly, but the mutants behaved like on jet-lag. Upon further inspection, the team found that phosphorylation eIF4E increases the output of Period proteins which are known for driving circadian rhythms in eclosion and locomotor activity, as reported in Nature Neuroscience.

“This study is the first to reveal a mechanism that explains how light regulates protein synthesis in the brain, and how this affects the function of the circadian clock,” said Sonenberg.

internal body clock

Image: AP Biology

“Disruption of the circadian rhythm is sometimes unavoidable but it can lead to serious consequences. This research is really about the importance of the circadian rhythm to our general well-being,” said co-author Shimon Amir. “We’ve taken an important step towards being able to reset our internal clocks – and improve the health of thousands as a result.”

We live in a really busy world, and with all the benefits that technology brought, there are also many health problems that come with it. Too much artificial light or staring in your computer screen on facebook until 1 AM definitely doesn’t help since it tricks the internal clock. This is why you might find it hard to wake up in the morning or constantly feel exhausted. Most of us can’t go back to waking up at first dusk and sleeping at nightfall though, like out great grandparents had. A drug that tweaks with eIF4E activity might regulate our internal clocks and actually synchronize our bodies with our 21st century lifestyle.

camping sleeping

A Week of Camping can Reset your Body Clock and Help you Sleep

Just one week of camping in the wild (or in any area without man-made light) can reset your body clock and return your natural sleep patterns, a new study has found.

camping sleeping

Camping can help your body return to your natural sleep pattern. Image credits: Ben Coffman

If you’re a night owl, if you’re having problems sleeping and just can’t set up a good sleep pattern – science has your problems figured out; all you need to do is take your sleeping bag and your tent and head for the mountains or the woods. Find a nice place without any non-natural lights, walk around, do some trekking or just read a book – do this for one week and your body clock will return to normal… or at least this is what a new study concluded.

Published in Current Biology, the study argues that our increased use of electrical light and reduced exposure to natural light caused modern humans to stray away from natural sleep patters and leads to overall lower sleep quality. Basically what happens is that our internal clocks will synchronize with the natural day-night cycle, but in modern society, we are subjected to so much artificial light that this pattern is disturbed. This is where the camping steps in – you get away from it all, rely only on natural light, and your body retunes, with our bodily night beginning at sunset and ending at sunrise.

The new study, conducted by Dr. Kenneth Wright and colleagues from the University of Colorado in the US ran for two weeks and included eight participants with an average age of 30 years. This is actually the one thing I have to object regarding this study – I’m not sure 8 participants is enough. I think in order to discuss statistical relevance, you need a bit more; but 8 is enough to raise some clear points.

The main problem in modern society is that people go to sleep later and later, and find it harder and harder to wake up in the morning.

“After exposure to natural light, we found the timing of the circadian clock to be approximately two hours earlier and [sleep-promoting hormone] melatonin offset to occur more than 50 minutes prior to wake time, suggesting that if human circadian and sleep timing was in synchrony with the natural light-dark cycle, the circadian low point in brain arousal would move to before the end of the sleep episode, making it easier to awaken in the morning,” the researchers found.

Despite having so few participants, the study was very well received in the scientific community. Dr Nicole Lovato, a sleep expert and Postdoctoral Research Fellow at Flinders University, described the research as “a novel approach to research aimed understanding the basic physiological processes which govern our daily lives.”

“It confirms existing knowledge regarding the effect of light exposure on the circadian rhythm, or body clock, and its timing in humans,” said Dr Lovato, who was not involved in the study.

The takeaway is that modern lighting almost certainly affects our sleep pattern negatively, but this can be fixed – if we subject ourselves to natural-light only. However, these changes are likely gradually lost, Wright says.

“This is likely to be due to those with delayed sleep phase disorder having longer period lengths of their circadian rhythms (24.8 hours instead of 24.3 hours). These people have a stronger tendency to delay with respect to our 24 hour world because their body clock ticks over more slowly.”

Journal Reference: Kenneth P. Wright Jr., Andrew W. McHill, Brian R. Birks, Brandon R. Griffin, Thomas Rusterholz, Evan D. Chinoy. Entrainment of the Human Circadian Clock to the Natural Light-Dark Cycle. DOI: http://dx.doi.org/10.1016/j.cub.2013.06.039.

Photo by Moyan Brenn

Early morning not the best time to drink coffee

Photo by Moyan Brenn

Photo by Moyan Brenn

In the US alone there are an estimated 100 million daily coffee drinkers, each contributing to a booming $18 billion industry. Of these, 68% claim they have their first coffee within the first hour of waking up. As a coffee drinker, I find myself guilty of the same practice, but apparently this isn’t the best time to enjoy your coffee. Why? Because there’s a big chance you’re wasting it, even though you might feel like it’s giving you that big slamming kick to start off the day.

Every person has his up and downs during a day, whether we’re talking about productivity, mood or energy. These swings are caused by the circadian clock – an  internal 24-hour clock  that alters your physiology and behavior by modifying your biological rhythm. The circadian clock is governed by the hypothalamus, a part of the brain that contains a number of small nuclei with a variety of functions. Most importantly, the hypothalamus is responsible for certain metabolic processes and other activities of the autonomic nervous system.

[RELATED] How much coffee is too much? study says 3 cups is max

But how does the hypothalamus knows how to regulate time and thus send signals that affect our biology, like telling us when its to go to sleep for instance? Through interactions with the sun of course. Previously it was shown that there exist connections between the retina and hypothalamus (the retinohypothalamic tract), so direct sensory input, in our case light, influences the body. But you probably already know this, innately – you don’t need to know the science to feel the effects. Ok, but how does this relate to coffee? We’re getting there.

Your circadian clock controls your metabolism function of the time of day, including alertness. Alertness is related to cortisol (the stress hormone). Cortisol blood levels peak between 8 and 9 AM, then again between noon to 1 PM, and between 5:30 to 6:30 PM. So, basically you are already on full alert naturally in the very first hour of the morning and drinking coffee during this time makes consumption inefficient. Instead, the best time of the day to enjoy your coffee would probably between 9:30 AM and 11:30 AM, when your cortisol levels are dropping before the next spike.

Tip via NeuroscienceDC

How a rooster knows to crow at dawn

Way back before clocks were a thing, people had another natural way of waking up: the rooster’s crow. Now, a new study shows that they are so exact, that they don’t even need the light of a new day to know when it’s dawn – they just rely on their internal clocks.


Nagoya University in Japan

A rooster crows in a deforested Amazon cloud forest.

A rooster crows in a deforested Amazon cloud forest.

were studying the genetic underpinnings of innate vocalizations – which is just a fancy way of saying they were studying vocal behaviors that animals instinctively do without learning them – when they paid some attention to the ever-present (when you don’t want it) rooster song.

“To our surprise, nobody [has] demonstrated the involvement of the biological clock in this well-known phenomenon experimentally,” study co-author Takashi Yoshimura, who specializes in biological clocks at Nagoya University, said in an email.

During their experiments, they used PNP roosters—an inbred strain of chickens used often in laboratories because of their genetic similarities—through two different light regimens; on a sidenote, I didn’t even know that such a thing as PNP roosters exist.

The first group was exposed to 12 hours of light, and 12 hours of twilight for 14 days. During this entire interval, researchers note that roosters start to crow two hours before daylight. Meanwhile, the other group was placed in dim light for the entire 14 day period. Yoshimura and Shimmura noticed that the animals started running on a 23.8-hour day and would crow when they thought it was dawn, according to the study, published March 18 in Current Biology.

Even when the roosters were exposed to sound and light stimuli to test whether external cues would also elicit crows, they found that the animals rely more on their internal clocks than on external stimuli.

“Crowing is a warning signal advertising territorial claims. Our preliminary data suggest that the highest ranked rooster has priority in breaking the dawn, and lower [ranking] roosters are patient enough to wait and follow the highest ranked rooster each morning,” said Yoshimura.

Kristen Navara, a hormone specialist in poultry at the University of Georgia in Athens who wasn’t involved in the study said she isn’t sure why nobody looked at this previously.

“I think many times we don’t think to study what appears right in front of us,” Navara, who wasn’t involved in the research, said by email.

“[For instance] we have definitely noticed in our own roosters that they begin to crow before dawn and have wondered why that was, but just never thought to test whether it was a circadian rhythm driven by an internal clock rather than an external cue.”

Via National Geographic

NASA to test sleep-aid coloured light bulbs

Space flight insomnia is quite a common issue, one for which space agencies don’t have a definite answer yet – but they’re working on it; one thing NASA plans to do is swap a fluorescent panel with a solid-state lighting module (SSLM) containing LEDs which produces a blue, whitish or red-coloured light depending on the time.

Some studies concluded that this change will not only combat insomnia, but it will also fight against depression, sickness and proneness to fatigue related mistakes. Currently, over half of all active astronauts rely on sleep medication, at some point, to sleep and get rest. For $11.2 million, NASA hopes to use the science of light to reduce the astronauts’ dependence on drugs and improve their overall performance.

“On some space shuttle missions up to 50% of the crew take sleeping pills, and, over all, nearly half of all medication used in orbit is intended to help astronauts sleep,” a NASA report said in 2001. “Even so, space travellers average about two hours sleep less each night in space than they do on the ground.”

Both humans and animals on Earth follow what is called a circadian rhythm – a 24-hour biological cycle involving cell regeneration, urine production and other functions critical to health. Basically, your body’s rhythm is driven by a circadian clock, and rhythms have been widely observed throughout the entire life forms – plants, animals, fungi and cyanobacteria.

What NASA wants to do is simulate a night-day cycle to minimise sleep disruption caused by the lack of a natural environment onboard missions such as the International Space Station. However, what I really love about this idea is that it could eventually help out a big part of the population on Earth which is suffering from sleep disorders.

“A significant proportion of the global population suffers from chronic sleep loss,” said Daniel Shultz at the Kennedy Space Center. “By refining multipurpose lights for astronauts safety, health and well-being in spaceflight, the door is opened for new lighting strategies that can be evolved for use on Earth.”