Sleep Archive

Research we're watching

An ongoing lack of sleep may lead to more fatty buildup in the arteries, according to a study in the January issue of the Journal of the American College of Cardiology. Researchers measured the sleep quality of 3,974 people with no history of heart disease.

Participants wore a sleep monitor for seven days and were then categorized based how much they slept: short sleep (six to seven hours a night), reference sleep (seven to eight hours a night) and long sleep (more than eight hours a night). Study authors also looked at how fragmented participants' sleep was throughout the nights. They then compared those findings to measures of arterial buildup in the heart and other parts of the body.

Why do heart attack rates rise on Monday mornings and the week after daylight savings time begins?

Deep inside your brain is a small cluster of cells that serves as your body's master clock. These cells govern your circadian rhythm, the 24-hour internal clock that keeps your body in sync with the day-night cycle. But nearly all your cells also have their own clocks to ensure that each one performs its unique role — such as producing proteins or releasing hormones — at the right time.

These biological timekeepers are under genetic control. But what happens if our behavior or environment is out of sync with our internal clocks? Understanding the potential health consequences of that misalignment is the focus of the Medical Chronobiology Program at Harvard-affiliated Brigham and Women's Hospital, says Dr. Frank Scheer, who directs the program.

Research we're watching

High exposure to bright, artificial outdoor lights during the night may result in sleepless nights for older adults. The more of this so-called light pollution that people were exposed to at night, the more they seemed to turn to medication to help them sleep, according to a study published in the Nov. 15, 2018, Journal of Clinical Sleep Medicine. People in brightly lit areas, as judged by satellite data, also seemed to take those drugs for longer and took higher doses than people who weren't exposed to nighttime light.

To come to their conclusions, the researchers looked at data on more than 50,000 adults ages 60 or older from the National Health Insurance Service–National Sample Cohort, a database of information collected on people who participated in health screenings between 2002 and 2013 in South Korea. Researchers compared the people's nighttime light exposure and their use of two sleep drugs, zolpidem (Ambien) and triazolam (Halcion).

Do you sometimes feel like the Energizer Bunny when his battery runs low? You might start the day strong, but by midafternoon, you can't quite keep going and going.

Fatigue afflicts everyone at one time or another. Assuming your doctor has ruled out serious medical causes, there are a few basic steps you can take to "recharge your batteries."

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In the journals

Adults who sleep only six hours per night may have a higher chance of being dehydrated, compared with those who sleep longer, according to recent research published online Nov. 5, 2018, by the journal Sleep. The findings suggest that some of the symptoms of inadequate sleep, such as fatigue, fuzzy thinking, and headache in the morning, may be due to dehydration.

Researchers looked at the risk of dehydration in approximately 20,000 U.S. and Chinese adults. In both populations, people who reported sleeping six or fewer hours had up to a 59% higher risk of dehydration compared with those who slept seven to eight hours on a regular basis. The researchers speculated that the finding may reflect the nightly rhythm of a hormone called vasopressin. During sleep, the pituitary gland in the brain uses vasopressin to signal the kidneys to retain fluid in the body rather than excreting it through urine.

Ask the doctors

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Q. After I had cataract surgery and facial surgery, I loved sleeping in my recliner for days on end. Does sleeping while sitting up put my brain and vital organs at risk since the blood supply has to travel uphill?

A. Sleeping sitting up in a recliner shouldn't be harmful. It could, in some cases, raise your risk of deep-vein thrombosis, a blood clot in a limb that can occur if your arms or legs are bent and you are motionless for hours. This sometimes occurs in people who sit still for long periods of time in an airplane seat. But provided you are comfortable and can recline back slightly, there should be few risks to sleeping upright, assuming it doesn't interfere with your ability to get a good night's sleep.

Occasionally these heart rhythm disruptions signal a more serious condition.

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Lately you've felt like a flipping fish is stuck inside your chest. You feel fine otherwise, but there it is again — flip, flop. It's gone as fast as it appears. But you're starting to worry: is it a sign of a serious heart problem?

Chances are what you're feeling is a condition called heart palpitations, which are usually harmless blips in the heart rhythm, explains Dr. Peter Zimetbaum, a professor of cardiovascular medicine at Harvard Medical School. Only occasionally are these rhythm disturbances the sign of a more serious heart problem that should be checked out.

In the journals

Are you excessively sleepy during the day? If so, you may have a higher risk of Alzheimer's disease, according to a recent study published online Sept. 5, 2018, by the journal Sleep.

Scientists asked 124 healthy older adults, average age 60, about how often they felt drowsy or fell asleep during the day when they would rather be awake, as well as their napping habits. The group then had regular PET scans over the next 15 years to look for beta-amyloid in the brain, high amounts of which are a hallmark for Alzheimer's.