sleep deprivation

How sleep deprivation hinders memory

October 2, 2018

Science Daily/Michigan State University

Researchers have conducted the largest experimentally controlled study on sleep deprivation to date, revealing just how detrimental operating without sleep can be in everything from bakers adding too much salt to cookies to surgeons botching surgeries.

 

While sleep deprivation research isn't new, the level at which distractions hinder sleep-deprived persons' memories and challenge them from successfully completing tasks was not clear until MSU's team quantified the impact.

 

"If you look at mistakes and accidents in surgery, public transportation and even operating nuclear power plants, lack of sleep is one of the primary reasons for human error," said Kimberly Fenn, associate professor of psychology and director of the MSU Sleep and Learning Lab. "There are many people in critical professions who are sleep-deprived. Research has found that nearly one-quarter of the people with procedure-heavy jobs have fallen asleep on the job."

 

Published in the Journal of Experimental Psychology: General, Fenn's research is unlike previous studies because of its focus on sleep deprivation's impact on completing tasks. These tasks, Fenn explained, involve following directions and include multiple steps.

 

Some basic errors, such as adding salt twice to a recipe, might not be so serious. However, some of the world's greatest human-caused catastrophes -- like Chernobyl, the Exxon Valdez oil spill and the Challenger explosion -- along with daily train and car accidents have sleep deprivation at least partially to blame, she said.

 

Fenn hopes that her lab's findings will shed light on how critical sleep is to completing any task, be it large or small.

 

"Every day, approximately 11 sponges are left inside of patients who have undergone surgery. That's 4,000 potentially dire missteps each year and an example of a procedural task gone terribly wrong that can result from sleep deprivation," Fenn said. "Our research suggests that sleep-deprived people shouldn't perform tasks in which they are interrupted -- or, only perform them for short periods."

 

To test sleep deprivation's impact on how people follow steps in a task, Fenn's team brought 234 people into the sleep lab at 10 p.m. That night, all of the participants worked on a sequence-based procedure that involved following a series of tasks in order. Periodically, they were interrupted and had to remember where they were in the procedure before picking up again. At midnight, half of the participants went home to sleep while the other half stayed awake all night at the lab. The next morning, everyone completed the procedure once again.

 

What Fenn's team found was a stark jump in errors for those who were sleep-deprived.

 

"All participants met performance criteria in the evening, but roughly 15 percent of participants in the sleep-deprived group failed in the morning, compared to 1 percent of those who slept," Fenn said. "Furthermore, sleep-deprived participants not only showed more errors than those who slept but also showed a progressive increase in errors associated with memory as they performed the task -- an effect not observed in those who slept. This shows that the sleep-deprived group experienced a great deal of difficulty remembering where they were in the sequence during interruptions."

 

Memory maintenance, the research found, was the real culprit keeping the sleep-deprived from completing tasks successfully. With hindered memory maintenance, it's much more difficult to pick up a task where you left off without missteps, Fenn explained.

 

Fenn also explained that distractions we face every day -- whether receiving a text message or simply answering a question -- are unavoidable but especially harmful to sleep-deprived people.

 

"Operating with reduced cognitive capacity has wide-ranging effects," Fenn said. "Students may pull all-nighters and not retain information for their exams. More worrisome, individuals working critical jobs may put themselves and other members of society at risk because of sleep deprivation. It simply cannot be overlooked."

https://www.sciencedaily.com/releases/2018/10/181002114027.htm

World's largest sleep study shows too much shut-eye can be bad for your brain

October 9, 2018

Science Daily/University of Western Ontario

Preliminary results from the world's largest sleep study have shown that people who sleep on average between 7 to 8 hours per night performed better cognitively than those who slept less, or more, than this amount.

 

Neuroscientists from Western University's Brain and Mind Institute released their findings today in the high-impact journal, SLEEP.

 

The world's largest sleep study was launched in June 2017 and within days more than 40,000 people from around the world participated in the online scientific investigation, which includes an in-depth questionnaire and a series of cognitive performance activities.

 

"We really wanted to capture the sleeping habits of people around the entire globe. Obviously, there have been many smaller sleep studies of people in laboratories but we wanted to find out what sleep is like in the real world," says Adrian Owen, Western's superstar researcher in Cognitive Neuroscience and Imaging. "People who logged in gave us a lot of information about themselves. We had a fairly extensive questionnaire and they told us things like which medications they were on, how old they were, where they were in the world and what kind of education they'd received because these are all factors that might have contributed to some of the results."

 

Approximately half of all participants reported typically sleeping less than 6.3 hours per night, about an hour less than the study's recommended amount. One startling revelation was that most participants who slept four hours or less performed as if they were almost nine years older.

 

Another surprising discovery was that sleep affected all adults equally. The amount of sleep associated with highly functional cognitive behaviour was the same for everyone (7 to 8 hours), regardless of age. Also, the impairment associated with too little, or too much, sleep did not depend on the age of the participants.

 

"We found that the optimum amount of sleep to keep your brain performing its best is 7 to 8 hours every night and that corresponds to what the doctors will tell you need to keep your body in tip-top shape, as well. We also found that people that slept more than that amount were equally impaired as those who slept too little," says Conor Wild, Owen Lab Research Associate and the study's lead author.

 

Participants' reasoning and verbal abilities were two of the actions most strongly affected by sleep while short-term memory performance was relatively unaffected. This is different than findings in most scientific studies of complete sleep deprivation and suggests that not getting enough sleep for an extended period affects your brain differently than staying up all night.

 

On the positive side, there was some evidence that even a single night's sleep can affect a person's ability to think. Participants who slept more than usual the night before participating in the study performed better than those who slept their usual amount or less.

https://www.sciencedaily.com/releases/2018/10/181009135845.htm

Sleep deprived people more likely to have car crashes

September 18, 2018

Science Daily/Oxford University Press USA

A new study indicates that people who have slept for fewer than seven of the past 24 hours have higher odds of being involved in and responsible for car crashes. The risk is greatest for drivers who have slept fewer than four hours.

 

Experts recommend that adults should sleep for seven to nine hours a night, yet government surveys indicate that one in five U.S. adults sleeps for fewer than seven hours on any given night, and one in three report usually sleeping for fewer than seven hours. An estimated seven percent of all motor vehicle crashes in the U.S. and 16 percent of fatal crashes involve driver drowsiness.

 

While the dangers of driving drowsy were already well known, this is the first peer-reviewed study to quantify the relationship between how much a driver has slept and his or her risk of being responsible for a crash. For this new study, researchers analyzed data from a previous study by the U.S. Department of Transportation, which involved in-depth investigations of a sample of 5,470 crashes, including interviews with the drivers involved.

 

The researchers here found that drivers who reported fewer than four hours of sleep had 15.1 times the odds of responsibility for car crashes, compared with drivers who slept for the recommended seven to nine hours in the preceding 24-hour period, comparable to U.S. Department of Transportation estimates of the crash risk of a driver with a blood alcohol concentration roughly 1.5 times the legal limit.

 

Researchers involved in the study also discovered that drivers who reported six, five, and four hours of sleep in the past 24 hours had 1.3, 1.9 and 2.9 times the odds of responsibility for a crash, respectively, compared with a driver who slept for seven to nine hours. Drivers who reported less than four hours of sleep had particularly elevated risk of single-vehicle crashes, which are more likely to result in injury or death. Drivers who had changed their sleep or work schedule in the past week and drivers who had been driving for 3 hours or longer without a break were also found to be at increased risk.

 

"Being awake isn't the same as being alert. Falling asleep isn't the only risk," said study author Brian Tefft. "Even if they manage to stay awake, sleep-deprived drivers are still at increased risk of making mistakes -- like failing to notice something important, or misjudging a gap in traffic -- which can have tragic consequences," he added.

https://www.sciencedaily.com/releases/2018/09/180918082041.htm

 

Broadband internet causes sleep deprivation

August 2, 2018

Science Daily/Bocconi University

Individuals with DSL access tend to sleep 25 minutes less than their counterparts without DSL Internet. They are significantly less likely to sleep between 7 and 9 hours, the amount recommended by the scientific community, and are less likely to be satisfied with their sleep, researchers find. The effect is largely driven by individuals that face time constraints in the morning and by the use of electronic devices in the evening (not by their use throughout the day)

 

Exploiting the fact that the deployment of broadband in Germany over the years was dependent on technical and historical reasons, they link data on broadband to surveys where individuals report their sleep duration. The researchers conclude that access to high-speed Internet reduces sleep duration and sleep satisfaction in individuals that face time constraints in the morning for work or family reasons.

 

"Individuals with DSL access tend to sleep 25 minutes less than their counterparts without DSL Internet. They are significantly less likely to sleep between 7 and 9 hours, the amount recommended by the scientific community, and are less likely to be satisfied with their sleep," Francesco Billari, a Full Professor of Demography at Bocconi University, Milan, and the Principal Investigator of the project DisCont, funded by the European Research Council, within which this research was conducted.

 

The effect that the authors find is largely driven by individuals that face time constraints in the morning and by the use of electronic devices in the evening (not by their use throughout the day). "Digital temptations may lead to a delay in bedtime, which ultimately decreases sleep duration for individuals who are not able to compensate for later bedtime by waking up later in the morning," Prof. Billari says.

 

The temptations individuals are prone to vary according to age, the scholars find. Among teenagers and young adults (aged 13-30), there is a significant association between insufficient sleep and time spent on computer games or watching TV or videos in the evening, while for older adults (31-59) the correlation is with the use of PCs and smartphones.

https://www.sciencedaily.com/releases/2018/08/180802102340.htm

Lack of Sleep May Increase Calorie Consumption

March 14, 2012

Science Daily/American Heart Association

If you don't get enough sleep, you may also eat too much -- and thus be more likely to become obese. That is the findings of researchers who presented their study at the American Heart Association's Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism 2012 Scientific Sessions.

 

Participants ate as much as they wanted during the study.

 

Researchers found:

  • ·      The sleep deprived group, who slept one hour and 20 minutes less than the control group each day consumed an average 549 additional calories each day.

 

  • ·      The amount of energy used for activity didn't significantly change between groups, suggesting that those who slept less didn't burn additional calories.

 

  • ·      Lack of sleep was associated with increased leptin levels and decreasing ghrelin -- changes that were more likely a consequence, rather than a cause, of over-eating.

 

"Sleep deprivation is a growing problem, with 28 percent of adults now reporting that they get six or fewer hours of sleep per night," said Andrew D. Calvin, M.D., M.P.H., co-investigator, cardiology fellow and assistant professor of medicine at the Mayo Clinic.

 

The researchers noted that while this study suggests sleep deprivation may be an important part and one preventable cause of weight gain and obesity, it was a small study conducted in a hospital's clinical research unit.

http://www.sciencedaily.com/releases/2012/03/120314170456.htm

 

Cannot sleep due to stress? Here is the cure

September 5, 2017

Science Daily/University of Tsukuba

Everyone empirically knows that stressful events certainly affect sound sleep. Scientists have found that the active component rich in sugarcane and other natural products may ameliorate stress and help having sound sleep.

 

In today's world ever-changing environment, demanding job works and socio-economic factors enforces sleep deprivation in human population. Sleep deprivation induces tremendous amount of stress, and stress itself is one of the major factors responsible for sleep loss or difficulty in falling into sleep. Currently available sleeping pills does not address stress component and often have severe side effects. Sleep loss is also associated with certain other diseases including obesity, cardiovascular diseases, depression, anxiety, mania deficits etc.

 

The research group led by Mahesh K. Kaushik and Yoshihiro Urade of the International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, found that octacosanol reduces stress and restores stress-affected sleep back to normal.

 

Octacosanol is abundantly present in various everyday foods such as sugarcane (thin whitish layer on surface), rice bran, wheat germ oil, bee wax etc. The crude extract is policosanol, where octacosanol is the major constituent. Policosanol and octacosanol have already been used in humans for various other medical conditions.

 

In the current study, authors made an advancement and investigated the effect of octacosanol on sleep regulation in mildly stressed mice by oral administration. Octacosanol reduced corticosterone level in blood plasma, which is a stress marker. The octacosanol-administered mice also showed normal sleep, which was previously disturbed due to stress. They therefore claim that the octacosanol mitigates stress in mice and restores stress-affected sleep to normal in mice. The sleep induced by octacosanol was similar to natural sleep and physiological in nature. However, authors also claimed that octacosanol does not affect sleep in normal animals. These results clearly demonstrated that octacosanol is an active compound that has potential to reduce stress and to increase sleep, and it could potentially be useful for the therapy of insomnia caused by stress. Octacosanol can be considered safe for human use as a therapy, because it is a food-based compound and believed to show no side effects.

 

Octacosanol/policosanol supplements are used by humans for functions such as lipid metabolism, cholesterol lowering or to provide strength. However, well-planned clinical studies need to be carried out to confirm its effect on humans for its stress-mitigation and sleep-inducing potentials. "Future studies include the identification of target brain area of octacosanol, its BBB permeability, and the mechanism via which octacosanol lowers stress," Kaushik says.

https://www.sciencedaily.com/releases/2017/09/170905111357.htm

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