A new way to optimize sleep and light exposure can reduce jet lag and improve alertness
Wearable technology can be used to calculate optimal personalized sleep and light schedule
December 18, 2019
Science Daily/Rensselaer Polytechnic Institute
Researchers explain how they have developed and demonstrated a series of algorithms that can analyze biometric information recorded by a smart device and then recommend the best combination of sleep and light to help a person readjust their circadian rhythm.
Whether you're traveling for work or for fun, nothing ruins the start of a trip quite like jet lag. Engineers affiliated with the Lighting Enabled Systems & Applications (LESA) Center at Rensselaer Polytechnic Institute have developed a way to deliver personalized advice using smart wearable technology that would help travelers adjust more quickly.
In a series of articles, including one published today in PLOS ONE, the researchers explain how they have developed and demonstrated a series of algorithms that can analyze biometric information recorded by a smart device and then recommend the best combination of sleep and light to help a person readjust their circadian rhythm.
"Using these algorithms and a mathematical model of a person's circadian rhythm, we have the ability to compute the best light to adjust your circadian rhythm and foster your well-being. This opens the opportunity to create a smart and healthy environment," said Agung Julius, an associate professor of electrical, computer, and systems engineering at Rensselaer and one of the authors on this paper.
The same, he said, goes for determining the sleep -- both how much and when it should be received -- a person needs.
Circadian rhythms are master internal clocks that help regulate many of our physiological processes, including sleep, metabolism, hormone secretion, and even how our brain functions. Energy, alertness, and other biological processes can suffer when that rhythm doesn't align with the clock one is actually trying to follow.
The Department of Defense is funding this research because of the benefits the researchers' findings could bring to the alertness of service members.
"The circadian and sleep processes are also very tightly related to your mental state and how alert you are," Julius said. "If you try to do something in the wrong time of day, your alertness is not going to be as effective as if you do it in the right time of day as defined by your circadian clock."
Julius explained that a person's circadian rhythm variation is typically determined using information gathered from a blood or saliva test that measures levels of the hormone melatonin. The problem with that traditional approach is that obtaining the results takes time and doesn't allow for instant analysis.
The LESA team, which includes John Wen, head of the Department of Electrical, Computer, and Systems Engineering at Rensselaer and co-author on this paper, has been working on algorithms that process data -- like heart rate and body temperature -- that can be collected from wearable smart technology and converted into an estimate of a person's circadian rhythm variation.
"The question is whether that kind of data can give you as accurate an estimation as the clinical standard," Julius said.
What the team has found and demonstrated is that the estimates their algorithms generated are in line with clinical hormone measurement techniques. Julius said these findings are indicative that the team's approach works.
"This work is important, because it characterizes the fundamental processes the human body uses to synchronize circadian and sleep processes. By developing biosensing analytics to characterize circadian phase, it is now possible to optimize the efficient use of light with appropriate spectral properties to help optimize and maintain human health and performance," said Robert Karlicek, the director of the LESA Center. "This will be important to other work related to lighting and health in LESA's clinical research test beds at Thomas Jefferson University and the University of New Mexico."
https://www.sciencedaily.com/releases/2019/12/191218153325.htm
Circadian clock plays unexpected role in neurodegenerative diseases
Seemingly counterintuitive evidence shows that disrupted sleep protects the brain
April 2, 2019
Science Daily/Northwestern University
Researchers induced jet lag in a fruit fly model of Huntington disease and found that jet lag protected the flies' neurons.
While your body might bemoan the many uncomfortable effects of jet lag, your brain may be thanking you for that cross-time zone travel.
In a new study, Northwestern University researchers induced jet lag in a fruit fly model of Huntington disease and found that jet lag protected the flies' neurons. The team then identified and tested a circadian clock-controlled gene that, when knocked down, also protected the brain from the disease.
The findings reveal potential new treatment pathways to slow the progression of or prevent neurodegenerative diseases.
"It seems counterintuitive, but we showed that a little bit of stress is good," said Northwestern's Dr. Ravi Allada, a circadian rhythms expert who led the research. "We subtly manipulated the circadian clock, and that stress appears to be neuroprotective."
The study will be published April 2 in the journal Cell Reports. Allada is the Edward C. Stuntz Distinguished Professor and chair of the department of neurobiology in Northwestern's Weinberg College of Arts and Sciences.
Patients with neurodegenerative diseases often experience profound disruptions in their circadian rhythms, or sleep-wake cycles. They may sleep more than usual or lose the ability to stay asleep. This can lead to nighttime wandering, increased agitation, general stress and a decreased quality of life.
"We have long known that a disrupted clock is an early indicator of neurodegenerative disease," Allada said. "In many cases, sleep disruption precedes any other symptom. But we didn't know whether the circadian disruption is a cause of the disease or a consequence of the disease."
To probe this question, Allada employed the fruit fly model of Huntington disease, a well-studied model organism for both circadian rhythms and neurodegenerative diseases. Although fruit flies might seem completely different from humans, the neurons that govern flies' sleep-wake cycles are strikingly similar to humans'. Fruit flies that have the mutant Huntington gene also demonstrate similar symptoms as humans with the disease: reduced lifespan, motor deficits, neurodegeneration, disrupted circadian rhythms and an accumulation of diseased proteins in the brain, which aggregate and cause neurons to die.
"Normally, fruit flies wake up, get very active, then go to sleep and become inactive," Allada explained. "It's a 24-hour pattern. In the Huntington model, there is no rhythm. The flies wake up and fall asleep all the time."
Allada's team altered the flies' circadian rhythms two different ways. For one group of flies, the researchers altered the flies' environment by changing the daily timing of light-dark cycles. This manipulation caused the flies to live a 20-hour day instead of a 24-hour day. And for another group of flies, the researchers mutated a gene that is well known for controlling the internal circadian clock.
"We essentially gave the flies jet lag for every day of their lives," Allada said. "It's like traveling four hours east every day."
In both cases, the mutant Huntington disease proteins aggregated less and fewer neurons died. Allada, who expected jet lag to inflict even more damage on the brain, was surprised. "We had wondered if the clock played a role in the disease," he said. "It turned out that the clock was important -- but in a manner that we did not predict."
Allada and his team were so fascinated by the result that they took the study one step further. They decided to screen through dozens of clock-controlled genes to pinpoint one that also might similarly protect the brain against neurodegenerative diseases.
The team zeroed in on a gene that encodes the "heat shock organizing protein," or "hop" for short. Not only is hop controlled by the body's circadian clock, the gene is also responsible for protein folding. Because misfolded proteins can result in many different neurodegenerative diseases, Allada thought hop made an interesting target. He and his team knocked down the hop gene in flies with the protein that causes Huntington disease and -- again -- were surprised. Knocking down the gene restored the flies' arrhythmic circadian clocks, reduced the aggregation of diseased proteins in the brain and reduced the number of neurons killed by those proteins.
"We thought that inhibiting this gene that helps your proteins fold properly would make things worse, but they got better," Allada said. "It again shows that a little bit of stress is probably good."
Next, Allada plans to test this method in a fruit fly model of Alzheimer's disease. He believes that targeting and knocking down the hop gene could potentially be an early intervention for slowing the progression of various neurodegenerative diseases.
https://www.sciencedaily.com/releases/2019/04/190402113220.htm
Teens come 'jet lagged' to school: Shifting sleeping patterns at weekends
September 15, 2017
Science Daily/Örebro University
A lack of sleep is associated with more absence and teens turn up jet lagged to school on Mondays, as shown in new research.
"My research is about understanding young people's sleeping patterns and what factors are linked to these. I am interested in why so many young people do not get enough sleep and what can be done about it," says Serena Bauducco, linked to the School of Law, Psychology and Social Work at Örebro University.
She has now presented her thesis showing that for teens who do not get enough sleep, their mental well-being is affected. Their sleep routines are not as good and they are more stressed and worried about school than those who get the sleep they need. These young people also bring their mobile phone or computer to bed to a greater extent than others.
In her thesis, Serena Bauducco also shows that problems with sleep are directly linked to a higher degree of absence from school.
"Those teens that showed symptoms of difficulties sleeping had three times as much absence than those who did not. That is quite a lot."
"We also checked other things that may be related to a high level of absence -- for example bullying, depression and anxiety. But the correlation between difficulties sleeping and why they did not go to school was very clear."
Her thesis is based on a study of approximately 2,700 upper secondary school pupils, aged 13-16. The study shows that teens sleep longer at weekends. And because they go to bed later and wake up later, they turn up for school with a changed sleeping cycle. In other words -- they suffer from jet lag.
"As a result, they may be tired and grumpy at school. Studies show that not getting enough sleep may affect learning," says Serena Bauducco.
For some, it may take three to four days to get back into routine -- and by then, the school week is nearly over. But for the large majority, the weekend-related jet lag is not a big deal. Almost all teens in the study did suffer from jet lag, but a majority of them did get enough sleep during the week.
"Nevertheless, it was still 20 per cent of those taking part in the study that on the whole did not get enough sleep," says Serena Bauducco.
As children approach adolescence, they develop later evening habits and it takes them longer to get to sleep once they have gone to bed. This is a natural part of their development, but it can obviously still be difficult to manage.
Serena Bauducco and her research colleagues therefore set up a programme with upper secondary school pupils in Örebro. The aim was to help the teens to create routines for themselves to get good sleep. It included simple things like not bringing their mobile phone into bed with them, and not sending or responding to text messages after 10 o'clock at night. But it also emphasised the importance of planning their time to make room for both school, spare time -- and sleep.
"One outcome was that those who had previously got the least sleep, improved their sleeping routines. They were less stressed and slept better."
So can you draw the conclusion that those teens who do not sleep very well, also find school work difficult?
"It is not something that we have looked at, but there are other studies that point to that."
There are schools in Sweden that have introduced later school start times to adjust to teenagers' biological rhythm. Some researchers say that sleeping in may lead to pupils performing better at school.
Serena Bauducco thinks this is an interesting development.
"A later start to the school day would lead to so many other things; staff have to change their working hours, bus time tables need changing and so on. I still think it is worth a try, as long as you also evaluate the effects of such structural change."
https://www.sciencedaily.com/releases/2017/09/170915164815.htm
Jet lag treatment? Blast of thin air can reset circadian clocks
October 20, 2016
Science Daily/Cell Press
We might not think of our circadian clock until we are jetlagged, but scientists continue to puzzle over what drives our biological timepiece. Now, a study has found that variations in surrounding oxygen levels can reset circadian clocks of mice. If confirmed in humans, the research could help inform how airlines moderate cabin air pressure.
Presently, light, food, and temperature are the best known cues that can influence circadian rhythms. But lead author Gad Asher, a senior scientist at the Weizmann Institute of Science in Rehovot, Israel, and his colleagues, including postdoctoral fellows Yaarit Adamovich and Benjamin Ladeuix, wondered if oxygen might also cue circadian rhythms since oxygen absorption in animals varies alongside meals and changing temperatures.
In the paper, the researchers show that changing the concentration of oxygen in cells by just 3%, twice a day, will synchronize mouse cells to a circadian rhythm. They suspected HIF1α was the link between oxygen and the circadian clock because HIF1α plays both a role in oxygen homeostasis in cells. They found that cells with low HIF1α levels won't synchronize in response to oxygen variations.
"It was extremely exciting to see that even small changes in oxygen levels were sufficient to efficiently reset the circadian clock," says Asher. "The study actually raises a lot of important questions; although we show that clock reset by oxygen is dependent on HIF1α, we did not yet fully identify how HIF1α integrates within the core clock circuitry."
The researchers further explored oxygen's effect on circadian rhythms with jetlag experiments. Just like humans, mice are prone to jetlag after a sudden shift in daylight hours. Mice were first left to eat, sleep and run on their wheels in air-controlled environments. Altering oxygen levels alone did not change their circadian rhythms but once mice experienced a 6-hour jump ahead in daylight hours, varying oxygen levels could help them adapt their eating, sleeping and running habits to the new time faster. They also saw that a small drop in oxygen levels 12 hours before the 6-hour daylight shift, or 2 hours afterwards, put the mice back on their circadian schedules faster and this too was dependent on HIF1α levels.
Presently, commercial airliners pressurize cabins to the same air density of a city 6,000-8,000 feet above sea level. This low-pressure saves wear and tear on the airplane, but enough passengers suffer from airsickness in response to this drop in oxygen levels that some airlines are considering ways to increase the pressure on flights. In fact, Boeing designed its new 787 Dreamliner so that it can be pressurized to the equivalent of lower altitudes for this reason. But in light of these findings, the researchers noted passengers may feel better with higher pressurized cabins during flights, but may also lose a potential advantage of recovering from jetlag. And in light of the effects of lower oxygen levels, the researchers now want to see what higher oxygen levels may do to the circadian clock.
"We are very looking forward to seeing the outcome of these experiments -- it will be interesting both from basic science and also from a practical standpoint," said Asher. "I believe passengers might be more enthusiastic to inhale oxygen-enriched air to alleviate jetlag in contrast to low oxygen."
Understanding how oxygen influences the circadian clock goes beyond jetlag. Cardiovascular disease, COPD, shift work sleep disorder, and other common health problems can result in tissues with low oxygen levels. "We show that oxygen works in mammals, specifically rodents, but it will be interesting to test whether oxygen can reset the clock of bacteria, plants, flies and additional organisms," says Asher.
https://www.sciencedaily.com/releases/2016/10/161020142746.htm