Posts Tagged "Sleep"

A study led by Johns Hopkins Medicine researchers suggests that awakening several times throughout the night is more detrimental to people’s positive moods than getting the same shortened amount of sleep without interruption.

As they report in the November 1 issue of the journal Sleep, researchers studied 62 healthy men and women randomly subjected to three sleep experimental conditions in an inpatient clinical research suite: three consecutive nights of either forced awakenings, delayed bedtimes or uninterrupted sleep.

Participants subjected to eight forced awakenings and those with delayed bedtimes showed similar low positive mood and high negative mood after the first night, as measured by a standard mood assessment questionnaire administered before bedtimes. Participants were asked to rate how strongly they felt a variety of positive and negative emotions, such as cheerfulness or anger.

But the researchers say significant differences emerged after the second night: The forced awakening group had a reduction of 31 percent in positive mood, while the delayed bedtime group had a decline of 12 percent compared to the first day. Researchers add they did not find significant differences in negative mood between the two groups on any of the three days, which suggests that sleep fragmentation is especially detrimental to positive mood.

“When your sleep is disrupted throughout the night, you don’t have the opportunity to progress through the sleep stages to get the amount of slow-wave sleep that is key to the feeling of restoration.”

Source: Science Daily

A new study may help explain why glucose tolerance — the ability to regulate blood-sugar levels — is lower at dinner than at breakfast for healthy people, and why shift workers are at increased risk of diabetes.

In a highly controlled study of 14 healthy individuals, a team led by researchers from Harvard-affiliated Brigham and Women’s Hospital (BWH) measured the independent influences that behavioral factors (mealtime, sleep/wake cycle, and more), the body’s internal clock (circadian system), and misalignment between these two components had on a person’s ability to control blood-sugar levels. The team reports its findings — with implications for shift workers and for the general public — in the week of April 13 in PNAS.

“Our study underscores that it’s not just what you eat, but also when you eat that greatly influences blood-sugar regulation, and that has important health consequences,” said co-corresponding author Frank Scheer, Harvard Medical School (HMS) associate neuroscientist and assistant professor of medicine in the Division of Sleep and Circadian Disorders and Departments of Medicine and Neurology at BWH. “Our findings suggest that the circadian system strongly affects glucose tolerance, independent from the feeding/fasting and sleep/wake cycles.”

Source: Harvard Gazette

Clinical depression is associated with a 30% increase of inflammation in the brain, according to a new study published in JAMA Psychiatry.

Inflammation is the immune system’s natural response to infection or disease. The body often uses inflammation to protect itself, such as when an ankle is sprained and becomes inflamed, and the same principle also applies to the brain. However, too much inflammation is unhelpful and can be damaging.

Increasingly, evidence is suggesting that inflammation may drive some depressive symptoms, such as low mood, loss of appetite and reduced ability to sleep.

What the new study set out to investigate was whether inflammation is a driver of clinical depression independent of other physical illness.

Researchers from the Centre for Addiction and Mental Health’s (CAMH) Campbell Family Mental Health Research Institute in Toronto, Canada, used positron emission tomography (PET) to scan the brains of 20 patients with depression and 20 healthy control participants.

In particular, the team closely measured the activation of microglia – immune cells that play a key role in the brain’s inflammatory response

The PET scans showed significant inflammation in the brains of the people with depression, and the inflammation was most severe among the participants with the most severe depression. The brains of people who were experiencing clinical depression exhibited an inflammatory increase of 30%.

Previous studies have examined markers of inflammation in the blood of depressed people, in an attempt to solve the “chicken or egg” debate of whether inflammation is a consequence of or contributor to major depression.

For instance, in 2012, a study conducted by Duke University Medical Center researchers and published in Biological Psychiatry found an association between the number of cumulative depressive episodes experienced by study participants and increased levels of an inflammation marker in their blood called C-reactive protein (CRP).

“Our results support a pathway from childhood depression to increased levels of CRP, even after accounting for other health-related behaviors that are known to influence inflammation. We found no support for the pathway from CRP to increased risk for depression,” said Duke study leader Dr. William Copeland.

Source: Medical News Today

Almost a century after the discovery that sleep helps us remember things, scientists are beginning to understand why.

During sleep, the brain produces chemicals that are important to memory and relives events we want to remember, scientists reported this week at the Society for Neuroscience meeting in Washington D.C.

“One of the most profound effects of a night of sleep is the improvement in our ability to remember things,” says Ravi Allada, a sleep researcher at Northwestern University. Yet this connection hasn’t been well-understood, he says.

That’s changing, thanks to recent research from scientists including Jennifer Choi Tudor from the University of Pennsylvania. At the meeting, Tudor presented a study involving a brain chemical (known as 4EBP2) that is produced during sleep and is thought to play a role in remembering new information.

Previous experiments have shown that sleep-deprived mice have memory problems and lower levels of this chemical. So the team tried injecting the chemical into the brains of mice, then deprived them of sleep. “With the injection, their memory is normal,” Tudor says.

Sleep is also a time when old memories can be modified and new memories can be formed, says Karim Benchenane from the National Center for Scientific Research in Paris. Benchenane was part of a team that studied the brains of rats while the rats were awake, as well as during sleep.

When the animals were awake and traveling around their cages, the scientists identified brain cells that became active only when the rats were in a specific location. During sleep, these same cells became active in the same order, indicating that the rats were reliving their travels and presumably strengthening their memories of places they’d been.

Source: NPR

Sleep apnea is a potential health risk for millions of Americans, and a new study points to a possible culprit behind the disorder: a “fat” tongue.

“This is the first study to show that fat deposits are increased in the tongue of obese patients with obstructive sleep apnea,” study senior author Dr. Richard Schwab, co-director of the Sleep Center at the University of Pennsylvania Medical Center, said in a news release from Sleep, which will publish the findings Oct. 1.

Sleep apnea is a common disorder in which the airways constrict during sleep, leading to repeated stops and starts in breathing. The telltale signs include chronic loud snoring, with periodic gasps or choking — and, for many people, daytime drowsiness because of poor sleep.

But the effects go beyond fatigue. Studies suggest those pauses in breathing stress the nervous system, boosting blood pressure and inflammation in the arteries.

Obese people tend to be at higher risk for sleep apnea, and Schwab’s team say the new findings may help explain the link between obesity and the breathing disorder.

The study included 90 obese adults with sleep apnea and 90 obese adults without the disorder.

The participants with sleep apnea had significantly larger tongues, tongue fat and percentage of tongue fat than those without sleep apnea, the researchers found. The tongue fat in the people with sleep apnea was concentrated at the base of the tongue.

In addition to increasing the size of the tongue, higher levels of tongue fat may prevent muscles that attach the tongue to bone from positioning the tongue away from the airway during sleep, Schwab’s group explained.

While the study found an association between tongue fat content and sleep apnea, it could not prove cause and effect.

However, the researchers believe future studies should assess whether removing tongue fat through weight loss, upper airway exercises or surgery could help treat sleep apnea.

“Tongue size is one of the physical features that should be evaluated by a physician when screening obese patients to determine their risk for obstructive sleep apnea,” American Academy of Sleep Medicine President Dr. Timothy Morgenthaler added in the news release.

“Effective identification and treatment of sleep apnea is essential to optimally manage other conditions associated with this chronic disease, including high blood pressure, heart disease, type 2 diabetes, stroke and depression,” he said.

Nearly 35 percent of U.S. adults — 78.6 million people — are obese, according to the U.S. Centers for Disease Control and Prevention.

Source: Detroit Free Press

The Presidential Healthcare Center now offers home sleep studies.  

Switching over to daylight saving time, and losing one hour of sleep, raised the risk of having a heart attack the following Monday by 25 percent, compared to other Mondays during the year, according to a new U.S. study released on Saturday.

By contrast, heart attack risk fell 21 percent later in the year, on the Tuesday after the clock was returned to standard time, and people got an extra hour’s sleep.

The not-so-subtle impact of moving the clock forward and backward was seen in a comparison of hospital admissions from a database of non-federal Michigan hospitals. It examined admissions before the start of daylight saving time and the Monday immediately after, for four consecutive years.

In general, heart attacks historically occur most often on Monday mornings, maybe due to the stress of starting a new work week and inherent changes in our sleep-wake cycle, said Dr. Amneet Sandhu, a cardiology fellow at the University of Colorado in Denver who led the study.

“With daylight saving time, all of this is compounded by one less hour of sleep,” said Sandhu, who presented his findings at the annual scientific sessions of the American College of Cardiology in Washington.

A link between lack of sleep and heart attacks has been seen in previous studies. But Sandhu said experts still don’t have a clear understanding of why people are so sensitive to sleep-wake cycles.

“Our study suggests that sudden, even small changes in sleep could have detrimental effects,” he said.

Sandhu examined about 42,000 hospital admissions in Michigan, and found that an average of 32 patients had heart attacks on any given Monday. But on the Monday immediately after springing the clock forward, there were an average of eight additional heart attacks, he said.

The overall number of heart attacks for the full week after daylight saving time didn’t change, just the number on that first Monday. The number then dropped off the other days of the week.

People who are already vulnerable to heart disease may be at greater risk right after sudden time changes, said Sandhu, who added that hospital staffing should perhaps be increased on the Monday after clocks are set forward.

“If we can identify days when there may be surges in heart attacks, we can be ready to better care for our patients,” he said.

The clock typically moves ahead in the spring, so that evenings have more daylight and mornings have less, and returns to standard time in the fall. Daylight saving time was widely adopted during World War I to save energy, but some critics have questioned whether it really does so and whether it is still needed.

Researchers cited limitations to the study, noting it was restricted to one state and heart attacks that required artery-opening procedures, such as stents. The study therefore excluded patients who died prior to hospital admission or intervention.

Source: Reuters

Waking up and not feeling rested isn’t just annoying. Researchers say that “non-restorative sleep” is the biggest risk factor for the development of widespread pain in older adults.

Widespread pain that affects different parts of the body — the main characteristic of fibromyalgia — affects 15 percent of women and 10 percent of men over age 50, according to previous studies.

To identify the triggers of such widespread pain, British researchers compiled demographic data as well as information on the pain and physical and mental health of more than 4,300 adults older than 50. About 2,700 had some pain at the study’s start, but none had widespread pain.

The results, published Feb. 13 in Arthritis & Rheumatology, show that restless sleep as well as anxiety, memory problems and poor health play a role in the development of this type of pain.

Three years after the study began, 19 percent of the participants had new widespread pain, the researchers found.

This new pain in various parts of the body was worse for those who had some pain at the beginning of the study. Of those with some prior pain, 25 percent had new widespread pain. Meanwhile, 8 percent of those with no pain at the start of the study had widespread pain three years later.

“While osteoarthritis is linked to new onset of widespread pain, our findings also found that poor sleep, [memory], and physical and psychological health may increase pain risk,” concluded the study’s leader, Dr. John McBeth, from the arthritis research center at Keele University in Staffordshire, England.

“Combined interventions that treat both site-specific and widespread pain are needed for older adults,” McBeth added in a journal news release.

Increasing age, however, was linked to a lower chance of developing widespread pain. Muscle, bone and nerve pain is more common among older people. Up to 80 percent of people 65 and older experience some form of pain on a daily basis, according to the news release.

While the study finds an association between poor sleep and widespread pain, it does not establish a direct cause-and-effect relationship.

SOURCE: Arthritis & Rheumatology, news release, Feb. 13, 2014

Ever feel like a zombie after just one sleepless night? Your brains certainly do: According to a new study in the journal Sleep, a single night of sleep deprivation results in an uptick of two enzymes usually associated with brain damage.

Researchers from Uppsala Universityin Sweden put 15 young, well-rested and healthy men through a night of total sleep deprivation. When they tested their blood the next morning, they found higher concentrations of the enzyme NSE and S-100B — both biomarkers of cell damage in the brain that could lead to cognitive problems and memory loss.

These findings follow research earlier this year showing that sleep “cleans” your brain of toxins and other substances than can destroy your neurons. “With this finding in mind, once could speculate that the sleep loss-induced rise in circulating levels of NSE and S-100B in our study may be a result of increased neuronal damage,” says study author Christian Benedict, PhD, associate professor of neuroscience at the university. NSE is an enzyme found in all neurons, and S-100B is the “glue of the brain”, Dr. Benedict says. Some research suggests that S100B is important for information processing, and elevated levels make it easy for doctors to detect brain cell damage through a simple blood test.

The researchers havent yet conducted the experiment on women. But findings could apply, since the levels of NSE and S-100B were significantly higher compared to participants’ natural baselines. Still, the levels weren’t higher than those found after a concussion. “A single night of sleep loss is not equally harmful as head injury,” says Dr. Benedict. “However, it does suggest that getting a regular, good night’s sleep may be useful for supporting brain health.”

Read more about the study here.

A study conducted by scientists at the University of Rochester Medical Center shows that, during sleep, the brain flushes out cellular waste. Though the study was conducted on mouse brains, the lead researcher said that the plumbing system also exists in dogs and baboons, and it’s logical to think that the human brain also clears away toxic substances. This study may provide new clues to treat Alzheimer’s disease and other disorders, in which toxic substances build up.

When we sleep, our brains get rid of gunk that builds up while we’re awake. The finding may mean that for people with dementia and other mind disorders, “sleep would perhaps be even more important in slowing the progression of further damage,” Dr. Clete Kushida, medical director of the Stanford Sleep Medicine Center, said in an email. Kushida did not participate in the study, which appeared in the journal Science.

People who don’t get enough shut-eye have trouble learning and making decisions, and are slower to react. But despite decades of research, scientists can’t agree on the basic purpose of sleep. Reasons range from processing memory, saving energy to regulating the body.

The latest work, led by scientists at the University of Rochester Medical Center, adds fresh evidence to a long-standing view: When we close our eyes, our brains go on a cleaning spree. The team previously found a plumbing network in mouse brains that flushes out cellular waste. For the new study, the scientists injected the brains of mice with beta-amyloid, a substance that builds up in Alzheimer’s disease, and followed its movement. They determined that it was removed faster from the brains of sleeping mice than awake mice.

The team also noticed that brain cells tend to shrink during sleep, which widens the space between the cells. This allows waste to pass through that space more easily.Though the work involved mouse brains, lead researcher Dr. Maiken Nedergaard said this plumbing system also exists in dogs and baboons, and it’s logical to think that the human brain also clears away toxic substances. Nedergaard said the next step is to look for the process in human brains.

In an accompanying editorial, neuroscientist Suzana Herculano-Houzel of the Federal University of Rio de Janeiro said scientists have recently taken a heightened interest in the spaces between brain cells, where junk is flushed out.

It’s becoming clearer that “sleep is likely to be a brain state in which several important housekeeping functions take place,” she said in an email.

The study was funded by the National Institute of Neurological Disorders and Stroke. In a statement, program director Jim Koenig said the finding could lead to new approaches for treating a range of brain diseases.

Source: USA Today