Posts Tagged "sleep cycle"

Adults who get too much or too little sleep may have the beginnings of “hardening” of the arteries, which can be an early sign of heart disease, according to a new study.

“Many people, up to one third or one fourth of the general population, suffer from inadequate sleep – either insufficient duration of sleep or poor quality of sleep,” said co-lead author Dr. Chan-Won Kim of Kangbuk Samsung Hospital of Sungkyunkwan University School of Medicine in Seoul, South Korea.

Several studies have linked inadequate sleep with an increased risk of heart attack and stroke, but other conditions like depression or obesity could influence this association, Kim told Reuters Health by email.  

“In contrast, we studied if sleep of inadequate duration or quality would be linked to early markers of heart disease in asymptomatic healthy adults free of heart disease,” Kim said.

For the study, more than 47,000 men and women, age 42 on average, completed a sleep questionnaire and had tests to detect lesions of calcium and plaque in the artery leading to the heart, an early sign of disease, and arterial stiffness in the leg, a sign of vascular aging.

According to their questionnaires, the participants’ average sleep duration was 6.4 hours per night, and about 84 percent said their sleep quality was “good.” The researchers considered those who got five hours or less per night to be “short” sleepers, and those who got nine or more hours to be “long” sleepers.

Short sleepers had 50 percent more calcium in their coronary arteries than those who slept for seven hours per night, according to the results in Arteriosclerosis, Thrombosis and Vascular Biology. Long sleepers had 70 percent more calcium than those who slept seven hours.

“The associations of too short or too long sleep duration and of poor sleep quality with early indicators of heart disease, such as coronary calcium and arterial stiffness, provides strong support to the increasing body of evidence that links inadequate sleep with an increased risk of heart attacks,” Kim said.

Source: Reuters

The Presidential Healthcare Center offers home sleep studies.

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