Sleep Loss

Sleep loss detrimental to blood vessels

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blood vessel
Blood vessel with an erythrocyte (red blood cell, E) within its lumen, endothelial cells forming its tunica intima (inner layer), and pericytes forming its tunica adventitia (outer layer) 

Lack of sleep has previously been found to impact the activation of the immune system, inflammation, carbohydrate metabolism and the hormones that regulate appetite. Now University of Helsinki researchers have found that sleep loss also influences cholesterol metabolism.

The study examined the impact of cumulative sleep deprivation on cholesterol metabolism in terms of both gene expression and blood lipoprotein levels. With state-of-the-art methods, a small blood sample can simultaneously yield information about the activation of all genes as well as the amounts of hundreds of different metabolites. This means it is possible to seek new regulating factors and metabolic pathways which participate in a particular function of the body.

“In this case, we examined what changes sleep loss caused to the functions of the body and which of these changes could be partially responsible for the elevated risk for illness,” explains Vilma Aho, researcher from the Sleep Team Helsinki research group.

The study established that the genes which participate in the regulation of cholesterol transport are less active in persons suffering from sleep loss than with those getting sufficient sleep. This was found both in the laboratory-induced sleep loss experiment and on the population level.

While analysing the different metabolites, the researchers found that in the population-level data, persons suffering from sleep loss had fewer high-density HDL lipoproteins, commonly known as the good cholesterol transport proteins, than persons who slept sufficiently.

Together with other risk factors, these results help explain the higher risk of cardiovascular disease observed in sleep-deprived people and help understand the mechanisms through which lack of sleep increases this risk.

“It is particularly interesting that these factors contributing to the onset of atherosclerosis, that is to say, inflammatory reactions and changes to cholesterol metabolism, were found both in the experimental study and in the epidemiological data,” Aho says.

The results highlight the health impact of good sleep. The researchers emphasise that health education should focus on the significance of good, sufficient sleep in preventing common diseases, in addition to healthy food and exercise. Even a small reduction in illnesses, or even postponing the onset of an illness, would result in significant cost savings for society at large.

 

SLEEP LOSS IMPEDES DECISION MAKING IN CRISIS, RESEARCH SHOWS

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The difference between life and death in the operating room, on the battlefield or during a police shootout often comes down to the ability to adapt to the unexpected. Sleep deprivation may make it difficult to do so, according to a Washington State University study published this month in the journal Sleep.

For the first time, WSU researchers created a laboratory experiment that simulates how sleep loss affects critical aspects of decision making in high-stakes, real-world situations. Their results provide a new understanding of how going without sleep for long periods can lead doctors, first responders, military personnel and others in a crisis situation to make catastrophic decisions.

Overcoming challenge of lab research

Recent history is full of examples of the sometimes devastating consequences of people operating without enough sleep.

Investigations into the Chernobyl nuclear power plant meltdown in Ukraine, the grounding of the Exxon Valdez oil tanker and the explosion of the space shuttle Challenger all concluded that sleep-deprived operators played a role in causing the accidents.

A long-standing conundrum for sleep scientists has been creating a controlled lab situation that sufficiently simulates the circumstances leading to severe lapses in real-world judgment. Previous laboratory research consistently showed sleep loss degrades attention, but its effects on demanding tests of cognition like decision making appeared to be relatively small.

“So there has been a disconnect between decision making in the lab where the effects of sleep loss appeared to be minimal and decision making in the real world where sleep loss can lead to big problems,” said Paul Whitney, WSU associate dean and professor of psychology. “Our goal was to bridge the gap and capture the essential elements of real-world decision making in a laboratory experiment.”

Adapting to feedback crucial

In a natural context, decision making is a dynamic process that requires a person to learn what is going on nearby as a result of his or her actions and changing circumstances. A surgeon, for instance, might notice a change in a patient’s vital signs midway through a procedure. The surgeon can then use this feedback decide a better course of action.

“A novel aspect of this study was using a simple laboratory task that captures the essential aspect of real-world decision making of adapting to new information in a changing situation,” said John Hinson, professor of psychology. “Prior studies of sleep loss and decision making have not realized how important adapting to changing circumstances is in determining when sleep loss will lead to decision making failures.”

Whitney, Hinson and Hans Van Dongen, director of the WSU Sleep and Performance Research Center at WSU Spokane, along with Melinda Jackson, now of the RMIT University, Victoria, Australia, recruited 26 healthy adults to take part in their study conducted at the Spokane sleep center.

Thirteen of the participants were randomly selected to go 62 hours without sleep two days into the study while the other half of the group was allowed to rest. For six days and nights, the participants lived in a hotel-like laboratory where they performed a specially designed reversal learning task to test their ability to use feedback to guide future decisions.

Mid-study switch confounds sleep deprived

In the task, subjects were shown a series of numbers that, unknown to them, were pre-assigned to have either a “go” (response) or “no go” (non-response) value. They had less than a second to decide whether or not to respond to each number shown.

Every time they correctly identified a number with a “go” value, they received a fictitious monetary reward. Errors resulted in a loss.

After a while, both the sleep-deprived group and the controls started to catch on and selected the right numbers. Then the tricky part came. The researchers reversed the contingencies so that participants had to withhold a response to the “go” numbers and respond to the “no go” numbers.

The switch confounded the sleep deprived participants. Even after being shown 40 numbers with reversed contingencies, they had almost zero success. On the other hand, the rested participants would catch on to the switch within 8-16 numbers.

Implications of sleep-loss risk

The data show that no matter how hard a person wants to make the right choice, sleep loss does something to the brain that simply prevents it from effectively using feedback. The study provides a new tool for investigating how sleep deprivation produces decision errors in real-life situations where information emerges over time.

“People in high-stakes environments are held accountable for their actions when they are fatigued just like everyone else,” Van Dongen said. “However, we now know that when someone is sleep-deprived their brain simply can’t process feedback from their actions and changing circumstances.

“Our findings tell us that putting sleep-deprived people in perilous environments is an inherently risky business and raises a number of medical, legal and financial implications,” he said.

The Impact Of Sleep Loss: Can It Affect The Size Of Your Brain?

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Lacking sleep can have quite an influence over your health; studies have shown that sleep deprivation can lead to poor memory skills, decreased quality of life, and impaired performance and alertness in accomplishing tasks. Not to mention a higher chance of developing high blood pressure, stress, attention deficit disorder, depression, and even obesity.

Now, researchers are beginning to examine the impact sleep deprivation might have on brain size. In a new study out of the University of Oxford, scientists examined 147 adults who were aged 20 to 84. They analyzed the link between lack of sleep and brain volume, finding that on average sleeping difficulties were associated with the “rapid decline in brain volume.” All of the participants underwent two MRI brain scans — about 3.5 years apart — and completed questionnaires about how they slept: whether they had a difficult time falling asleep, staying asleep, or sleeping a solid amount of hours every night. About 35 percent of the participants were shown to have poor sleep quality, according to the authors.

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But the researchers still aren’t sure whether they can determine from this study that people with low sleep quality will indeed experience a decline in brain volume. Though there is a link, there is no telling if it’s a causation or just a correlation. What they did find, however, was that rapid decline in brain volume was more strongly apparent in people over the age of 60.

“It is not yet known whether poor sleep quality is a cause or consequence of changes in brain structure,” study author Claire E. Sexton of the University of Oxford said in the press release. “There are effective treatments for sleep problems, so future research needs to test whether improving people’s quality of sleep could slow the rate of brain volume loss. If that is the case, improving people’s sleep habits could be an important way to improve brain health.”

This is just another study that suggests how important sleep is for the brain. Sleep is something of the “brain’s housekeeper,” due to its ability to “cleanse” the brain and repair it. A recent study out of the University of Pennsylvania School of Medicinefound that chronic sleep deprivation could be quite serious in that it causes your brain to lose neurons.

“In general, we’ve always assumed full recovery of cognition following short- and long-term sleep loss,” Dr. Sigrid Veasey, an author of the UPenn study and associate professor of Medicine at the Perelman School of Medicine, said in a press release. “But some of the research in humans has shown that attention span and several other aspects of cognition may not normalize even with three days of recovery sleep, raising the question of lasting injury in the brain. We wanted to figure out exactly whether chronic sleep loss injures neurons, whether the injury is reversible, and which neurons are involved… This is the first report that sleep loss can actually result in a loss of neurons.”

So give sleep a chance to be your “brain’s housekeeper,” because it is likely far more important to your brain — and overall health — than you think.

Penn Study in Fruitflies Strengthens Connection Among Protein Misfolding, Sleep Loss, and Age

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 Pulling an “all-nighter” before a big test is practically a rite of passage in college. Usually, it’s no problem: You stay up all night, take the test, and then crash, rapidly catching up on lost sleep. But as we age, sleep patterns change, and our ability to recoup lost sleep diminishes.

Researchers at the Perelman School of Medicine, University of Pennsylvania, have been studying the molecular mechanisms underpinning sleep. Now they report that the pathways of aging and sleep intersect at the circuitry of a cellular stress response pathway, and that by tinkering with those connections, it may be possible to alter sleep patterns in the aged for the better – at least in fruit flies.

Nirinjini Naidoo, PhD, associate professor in the Center for Sleep and Circadian Neurobiology and the Division of Sleep Medicine, led the study with postdoctoral fellow Marishka Brown, PhD, which waspublished online before print in the journal Neurobiology of Aging.

Increasing age is well known to disrupt sleep patterns in all sorts of ways. Elderly people sleep at night less than their younger counterparts and also sleep less well. Older individuals also tend to nap more during the day. Naidoo’s lab previously reported that aging is associated with increasing levels of protein unfolding, a hallmark of cellular stress called the “unfolded protein response.”

Protein misfolding is also a characteristic of several age-related neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases, and as it turns out, also associated with sleep deprivation. Naidoo and her team wanted to know if rescuing proper protein folding behavior might counter some of the detrimental sleep patterns in elderly individuals.

Using a video monitoring system to compare the sleep habits of “young” (9–12 days old) and “aged” (8 weeks old) fruit flies, they found that aged flies took longer to recover from sleep deprivation, slept less overall, and had their sleep more frequently interrupted compared to younger control animals. However, adding a molecule that promotes proper protein folding – a molecular “chaperone” called PBA — mitigated many of those effects, effectively giving the flies a more youthful sleep pattern. PBA (sodium 4-phenylbutyrate) is a compound currently used to treat such protein-misfolding-based diseases as Parkinson’s and cystic fibrosis.

The team also asked the converse question: Can protein misfolding induce altered sleep patterns in young animals. Another drug, tunicamycin, induces protein misfolding and stress, and when the team fed it to young flies, their sleep patterns shifted towards those of aged flies, with less sleep overall, more interrupted sleep at night, and longer recovery from sleep deprivation.

Molecular analysis of sleep-deprived and PBA-treated flies suggested that PBA acts through the unfolded protein response. PBA, Naidoo says, had two effects on aged flies: it “consolidated” baseline sleep, increasing the total amount of time slept and shifted recovery sleep, after sleep deprivation, to look more like that of a young fly.

“It rescued the sleep patterns in the older flies,” she explains.

These results, Naidoo says, suggest three key messages. First, sleep loss leads to protein misfolding and cellular stress, and as we age, our ability to recover from that stress decreases. Second, aging and sleep apparently form a kind of negative “chicken-and-egg” feedback loop, in which sleep loss or sleep fragmentation lead to cellular stress, followed by neuronal dysfunction, and finally even poorer-quality sleep.

Sleep recharges neuronal batteries, Naidoo explains, and if a person is forced to stay awake, those batteries run down. Dwindling physiological resources must be devoted to the most critical cell functions, which do not necessarily include protein homeostasis. “Staying awake has a cost, and one of those costs is problems with protein folding.”

Finally, and most importantly, she says these results suggest — assuming they can be replicated in mice and humans – that it may be possible using drugs such as PBA to “fix sleep” in aged or mutant animals.

“People know that sleep deteriorates with aging,” Naidoo says, “But this might be able to be stopped or reversed with molecular chaperones.” Her team is now looking to determine if a similar situation exists in mammals and if better sleep translates into longer lifespan.