Both too much and too little sleep can harm the heart

Too much and too little sleep can hurt the heart according to a recent study.

Otherwise healthy people who have poor sleep habits may be putting themselves at risk for early signs of heart disease, a new study suggests.

Folks who get too much or too little sleep -- or not enough quality rest -- are more likely to suffer from stiffened arteries and calcium deposits on the walls of their major arteries, said study lead author Dr. Chan-Won Kim.

"Coronary calcium develops way before heart attack symptoms occur, and a greater amount of calcium in the coronary arteries predicts future development of heart disease," said Kim, a clinical associate professor in the Center for Cohort Studies at Kangbuk Samsung Hospital in Seoul, South Korea.

The sweet spot appears to be about seven hours of sleep, the researchers reported. People who got more or less sleep tended to have increased signs of potential future heart problems.

Earlier studies have linked poor sleep to bad heart health, but this research goes a step further by looking for precursors of heart disease in people who appear healthy, said Dr. David Meyerson, a cardiologist at Johns Hopkins Bayview Medical Center in Baltimore and a national spokesman for the American Heart Association.

Because the study authors took this route, their implications more directly highlight sleep as a potential risk factor for heart disease, Meyerson said.

"Quality and duration of sleep is not always asked by every physician during a cardiovascular risk assessment session, and perhaps it should be," he said.

While the study uncovered a link between poor sleep and potential heart problems, it did not prove a cause-and-effect connection.

The study involved more than 47,000 young and middle-aged adults who completed a sleep questionnaire and had advanced tests to measure arterial stiffness and detect early artery lesions caused by calcium deposits.

The findings revealed that study participants who:

• got five or fewer hours of sleep a day had 50 percent more calcium in their arteries than those who slept seven hours a day.
• slept nine or more hours a day had at least 70 percent more calcium compared to those who slept seven hours.
• reported poor sleep quality had more than 20 percent more calcium than those who reported good sleep quality.

"Since we studied apparently healthy young and middle-age men and women without major diseases, it is unlikely that other health problems can explain the association between extreme sleep duration and early markers of heart disease," Kim said.

Doctors don't yet know exactly why the proper amount of sleep appears to protect heart health, said Meyerson and Dr. Mark Urman, a cardiologist with Cedars-Sinai Heart Institute in Los Angeles.

During sleep, a complex dance of metabolic changes, hormone releases, body repair and brain refreshment takes place. These processes affect blood pressure, blood sugar, inflammation, stress hormones and a host of other factors that can increase risk of heart disease, the cardiologists said.

"We know our bodies every day need this ability to recharge our batteries, to put everything at ease and calm everything down," Urman said, adding that poor sleep has been linked to heart risk factors like diabetes and obesity.

Sleep should be considered part of an overall heart-healthy lifestyle, Urman said.

"This adds to the importance of getting a good night's sleep on a regular basis, in addition to regular exercise and a heart-healthy diet, in reducing risk of heart disease," he said. "This is one more thing that's part of that package."

People who want to improve their sleep should dim the lights in their living room or bedroom as bedtime approaches, and they should go to bed at the same time every day, Kim said.

"It is also important to avoid exposure to electronic media at bedtime," Kim said. He added that "people who experience inadequate sleep need to avoid caffeine-containing beverages after lunch."

The study findings were published Sept. 10 in the American Heart Association journalArteriosclerosis, Thrombosis and Vascular Biology.

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Increased stroke risk seen with people who sleep too much

Sleeping for more than 8 hours per day can increase a person's risk of having a stroke.

People who sleep for more than eight hours a day have an increased risk of stroke, according to a study by the University of Cambridge -- and this risk doubles for older people who persistently sleep longer than average. However, the researchers say it is unclear why this association exists and call for further research to explore the link.

Previous studies have already suggested a possible association between sleep and risk of stroke, but today's study, published in the journal Neurology, is the first to provide detailed information about the British population and to examine the relationship between a change in sleep duration over time and subsequent stroke risk.

Researchers from the Department of Public Health and Primary Care at the University of Cambridge followed just under 10,000 people aged 42-81 years of age from the European Prospective Investigation into Cancer (EPIC)-Norfolk cohort over 9.5 years. During 1998-2000 and then again four years later, they asked the cohort how many hours on average they slept in a day and whether they generally slept well. Almost seven out of ten participants reported sleeping between six and eight hours a day, whilst one in ten reported sleeping for over eight hours a day. Participants who slept for less than six hours or more than eight hours were more likely to be older, women and less active.

Over the almost ten year period of the study, 346 participants suffered a stroke, either non-fatal or fatal stroke. After adjusting for various factors including age and sex, the researchers found that people who slept longer than eight hours a day were at a 46% greater risk of stroke than average. People who slept less than six hours a day were at an 18% increased risk, but the small number of people falling in this category meant the association was not statistically significant*.

Participants who reported persistently long sleep -- in other words, they reported sleeping over eight hours when asked at both points of the study -- were at double the risk of stroke compared to those with persistently average sleep duration (between six and eight hours a day). This risk was even greater for those whose reported sleep increased from short to long over the four years -- their risk was close to four times that of people who maintained an average sleep duration.

In addition to studying the EPIC-Norfolk cohort, the researchers carried out a study of combined data from 11 other studies related to identify the association between sleep duration and patterns of stroke risk. Their final analysis, including 560,000 participants from seven countries, supported the findings from the EPIC-Norfolk cohort study.

Yue Leng, a PhD candidate at the University of Cambridge, says: "It's apparent both from our own participants and the wealth of international data that there's a link between sleeping longer than average and a greater risk of stroke. What is far less clear, however, is the direction of this link, whether longer sleep is a symptom, an early marker or a cause of cardiovascular problems."

While older people have less work and fewer social demands and therefore often have the option of sleeping longer, previous research has shown that in fact, they tend to sleep on average for shorter periods.

The researchers say it is unclear yet why the link between sleep and stroke risk should exist. Lack of sleep has been linked with factors such as disrupted metabolism and raised levels of the 'stress hormone' cortisol, all of which may lead to higher blood pressure and increased stroke risk. However, the current study suggests that the association between longer sleep duration and higher risk of stroke was independent of normal risk factors for cardiovascular disease.

Professor Kay-Tee Khaw, senior author on the study, adds: "We need to understand the reasons behind the link between sleep and stroke risk. What is happening in the body that causes this link? With further research, we may find that excessive sleep proves to be an early indicator of increased stroke risk, particularly among older people."

The study was supported by the Medical Research Council and Cancer Research UK.

*The absolute risk of stroke was 4.1% for less than six hours' sleep, 3.1% for six to eight hours, and 5.3% for over eight hours. Note: these figures are before adjustment for age, sex, etc. -- figures for after adjustment were not available.

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Neighborhood's Socioeconomic Level Linked to Sleep Duration

A study found that a neighborhood's amount of socioeconomic deprivation was linked to both longer and shorter sleep duration than is recommended for adults.

A new study of adult twins suggests that the level of socioeconomic deprivation in a neighborhood is associated with the sleep duration of residents.

Results show that increased socioeconomic deprivation was significantly associated with decreased sleep duration across all twins. Further analysis within twin pairs found that this association remained significant after accounting for genetics and shared family environment, indicating a robust relationship.

"These results are a starting point for discussing the impact that neighborhood-level factors have on sleep duration," said principal investigator Dr. Nathaniel Watson, president-elect of the American Academy of Sleep Medicine and professor of neurology at the University of Washington in Seattle, where he is co-director of the University of Washington Medicine Sleep Center and director of the Harborview Medical Center Sleep Clinic. "If we improve upon social deprivation, we may have an opportunity to improve upon habits that influence how long people sleep."

The research abstract was published recently in an online supplement of the journal Sleep and was presented in Minneapolis, Minnesota, at SLEEP 2014, the 28th annual meeting of the Associated Professional Sleep Societies LLC.

The study group comprised 2,202 twin pairs -- 1,268 monozygotic pairs and 934 dizygotic pairs -- from the University of Washington Twin Registry. The mean age of study subjects was 37 years, and 62.1 percent were female. Mean self-reported nightly sleep duration was 7.4 hours.

Community socioeconomic deprivation was measured using the Singh Index (SI), a composite, area-level measure. The index combines 17 indicators measuring factors such as poverty, income, education and housing.

Watson's research team also found an intriguing gene by environment interaction. As socioeconomic deprivation increased, the total genetic and non-shared environmental variability of sleep duration also went up.

"The more socioeconomically deprived the neighborhood, the more erratic the sleep duration, both shorter and longer than the healthy seven to nine hours per night that we recommend," he said.

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Too much and too little sleep indicate memory problems

This article claims that both too much and too little sleep can lead to memory problems in older women.

Seniors who slept too little or too much during midlife or after are at increased risk for memory problems, as are those whose sleep habits changed over time, a new study suggests.

Researchers looked at more than 15,000 women, 70 and older, who took part in a large study of health professionals. The women were depression- and stroke-free when they underwent their initial assessment.

Participants who slept five hours or less, or nine hours or more a day -- either in midlife or later life -- had worse memory than those who slept seven hours a day. The difference in memory was equivalent to nearly two extra years of age, the researchers said.

Women whose amount of sleep changed by more than two hours a night over time had poorer memory than those who had no sleep changes, according to the study published May 1 in the Journal of the American Geriatrics Society.

"Given the importance of preserving memory into later life, it is critical to identify modifiable factors, such as sleeping habits, that may help achieve this goal," study leader Elizabeth Devore, of Brigham and Women's Hospital in Boston, said in a hospital news release.

"Our findings suggest that getting an 'average' amount of sleep, seven hours per day, may help maintain memory in later life and that clinical interventions based on sleep therapy should be examined for the prevention of [mental] impairment," she added.

The study adds "to our knowledge about how sleep impacts memory. More research is needed to confirm these findings and explore possible mechanisms underlying these associations," Devore concluded.

While the study found an association between sleep time during midlife and older age and memory function in older women, it did not prove a cause-and-effect relationship.

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Too much or too little sleep can raise risk of depression

Two studies show that a person's risk of depression can increase with both too much and not enough sleep.

Too much or too little sleep can increase the risk of depression, according to two new studies.

Inappropriate amounts of sleep may activate depression-related genes, researchers report in the Feb. 1 issue of the journal Sleep.

One study included more than 1,700 adult twins. Among those who got normal amounts of sleep (seven to nearly nine hours a night), the genetic influence on symptoms of depression was 27 percent versus 53 percent for those who slept only five hours a night, and 49 percent among those who slept 10 hours a night.

"Both short and excessively long sleep durations appear to activate genes related to depressive symptoms," lead investigator Dr. Nathaniel Watson, an associate professor of neurology and co-director of the University of Washington Medicine Sleep Center in Seattle, said in a journal news release.

Ensuring that patients get optimum levels of sleep may be one way to boost the effectiveness of treatments for depression, he added.

The second study included more than 4,100 youngsters aged 11 to 17. It found that sleeping six hours or less per night increased their risk for major depression, which in turn increased their risk for too little sleep.

"These results are important because they suggest that sleep deprivation may be a precursor for major depression in adolescents, occurring before other symptoms of major depression and additional mood disorders," principal investigator Dr. Robert Roberts, professor of behavioral sciences in the School of Public Health at the University of Texas Health Science Center in Houston, said in the news release.

"Questions on sleep disturbance and hours of sleep should be part of the medical history of adolescents to ascertain risk," he added.

"Healthy sleep is a necessity for physical, mental and emotional well-being," Dr. M. Safwan Badr, president of the American Academy of Sleep Medicine, said in the news release. "This new research emphasizes that we can make an investment in our health by prioritizing sleep."

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