February 6, 2017
|When we are no longer able to change a situation, we are challenged to change ourselves.
-- Viktor Frankl
|In this Issue|
Time Outdoors May Deliver Better Sleep
Camping and exposure to natural light helps prime your body for an earlier bedtime, researchers say
THURSDAY, Feb. 2, 2017 (HealthDay News) -- Spending time in the outdoors may improve your sleep, a small study suggests.
Researchers found that a week of winter camping reset the body's "clock" to be more in tune with nature's light-and-dark cycle. The result was longer sleep.
The findings, the study authors said, add to evidence that time in the sun and the dark helps people get to sleep at a decent hour.
The study also highlights how modern living -- so heavy on artificial light -- may thwart our sleep.
"It's clear that modern environments do influence our circadian rhythms," said Kenneth Wright, the study's senior researcher.
Circadian rhythms refer to the shifts in the body's biological processes that happen over 24 hours, partly in response to light and darkness.
But while our ancestors may have gone to bed early and risen with the sun, that's not true today, said Wright, a professor at the University of Colorado, Boulder. Many people get little outdoor time during the day, then stay up late -- eyes trained to artificial light from glowing computer, phone and TV screens.
In a 2013 study, Wright's team found that a week of summer camping -- with no smartphones -- reset people's internal clocks to be in rhythm with nature's.
Saliva samples showed that levels of the "sleep hormone" melatonin shifted compared with a typical week at home. Melatonin levels started to rise around sunset, and the campers' "biological night" kicked in about two hours earlier.
Accordingly, the campers turned in much earlier than their usual midnight bedtime at home. They also woke up earlier, closer to sunrise.
For the new study, published Feb. 2 in Current Biology, Wright's team recruited five hardy volunteers for a week of December camping in the Colorado Rockies. Again, the researchers used saliva samples to detect shifts in campers' melatonin levels, versus a week at home.
Campers' biological nights started over 2.5 hours sooner, Wright said, and they went to bed earlier.
There was, however, one difference from the earlier study. Winter campers did not rise earlier. So they ended up getting more than two hours of extra sleep.
The study doesn't establish a direct cause-and-effect relationship between time outdoors and better sleep. And Wright said temperature may have played a role in the extra morning shut-eye. People may have simply preferred to stay in the warmth of their tents and sleeping bags than face the early morning chill, he noted.
In a second experiment, the researchers had 14 people either spend a weekend at home or camping -- this time in the summer. They found that even a weekend outdoors caused people to shift their biological clock.
In contrast, people who stayed at home showed the opposite pattern: On weekends, their biological night started even later than it typically did on a weekday.
Why does all of this matter?
According to Wright, there is evidence that people with "late" internal clocks face some health risks. They have higher rates of obesity, diabetes and depression, and are more likely to suffer daytime fatigue and accidents.
"We don't completely understand why that is," Wright said.
But, he added, it is wise to not only get enough hours of sleep, but to make sure you're sleeping at the "right" times.
A researcher who was not involved in the study agreed.
There is evidence, for example, that exposure to morning light is associated with appetite and weight control, said Dr. Phyllis Zee.
She said the new experiments are important because they demonstrate just how powerful exposure to natural light -- and darkness -- can be.
"Just two days of summer camping reset people's clocks," said Zee, director of the Center for Circadian and Sleep Medicine at Northwestern University in Chicago.
If you're not the camping type, there is good news. "This study is not about camping," Wright said.
He encouraged people to get out in the sun when they can each day, then minimize bright artificial light at night. That's particularly important, Wright said, when it comes to blue/green light like the glow from your phone or computer screen.
In the natural world, Zee explained, blue/green light is most pervasive in the morning. Later in the day, natural light shifts toward a red/orange frequency.
She and Wright said research like this can also inform architecture and lighting design. If people are holed up indoors every day, they should be exposed to natural light -- or artificial light that mimics natural light -- as much as possible.
The National Sleep Foundation has more on circadian rhythms and sleep.
Eye-Opening Research on Astronauts' Vision Problems
Zero-gravity conditions prevent normal pressure variations around the brain, researchers say
FRIDAY, Feb. 3, 2017 (HealthDay News) -- Vision deterioration is a major problem for astronauts who spend extended periods of time in space. Now researchers have identified the likely cause of the problem and a possible way to prevent it.
According to researchers at UT Southwestern Medical Center at Dallas, the probable cause is the lack of a day-night cycle in intracranial pressure -- pressure around the brain.
The new study showed that intracranial pressure in zero-gravity conditions, such as exists in space, is greater than when people stand or sit on Earth, but lower than when people sleep.
It might be possible to prevent the problem by using a vacuum device to lower pressure for part of each day, the investigators suggested.
"Astronauts are basically supine [lying face upward] the entire time they are in space. The idea is that the astronauts would wear negative pressure clothing or a negative pressure device while they sleep, creating lower intracranial pressure for part of each 24 hours," study first author Dr. Justin Lawley said in a university news release. Lawley is an instructor in internal medicine.
The study suggests that the constant pressure on the back of the eye causes the vision deterioration in astronauts during extended space missions, such as on the International Space Station.
Study senior author Dr. Benjamin Levine said that "the information from these studies is already leading to novel partnerships with companies to develop tools to simulate the upright posture in space while astronauts sleep."
Levine, a professor of internal medicine, explained that the aim is to normalize the daily variability in intracranial pressure and eliminate the remodeling behind the eye.
The study was published Jan. 16 in the Journal of Physiology.
NASA has more on vision impairment and intracranial pressure.
Gene Discoveries Offer New Height Insights
Long and short of the findings: Scientists may better understand growth disorders
WEDNESDAY, Feb. 1, 2017 (HealthDay News) -- Dozens of newly identified gene variants may have a major influence on height, British researchers say.
"The new genetic variants we found are rare in the population but their large effects on human height have revealed important new insights into human skeletal growth," said Panos Deloukas, senior co-lead author of a new report on the genes. He's a professor at Queen Mary University of London.
The identified genes will be helpful in predicting a person's risk of developing certain growth disorders, Deloukas said in a university news release.
Hundreds of gene variants that affect height by less than 1 millimeter had already been pinpointed. But, the 83 newly identified gene variants can result in differences of up to 2 centimeters -- about three-quarters of an inch. That's more than 10 times the average impact of the previously known variants, the researchers said.
The findings are from an analysis of DNA from more than 700,000 people worldwide.
Study co-lead analyst Andrew Wood is with the University of Exeter in England. "Our latest discovery means that we can now explain over a quarter of the heritable factors involved in influencing a person's height," Wood said.
The research team said it was known that a person's height is mostly determined by genetics -- tall parents tend to have taller children and vice versa. But less is known about how a baby grows into an adult, the researchers noted.
How the body grows from a 20-inch baby into a perfectly proportioned adult, and how some people end up 18 inches taller than others, is a fascinating but poorly understood aspect of biology, Wood said.
The researchers added there is hope that one day this knowledge may be used to develop a precision medicine approach for dealing with growth disorders.
The findings appear in the Feb. 2 issue of the journal Nature.
The U.S. National Institute of General Medical Sciences has more about genetics.
Poverty Takes 2 Years Off Your Life: Study
Lack of money can be as damaging to health as inactivity, researchers find
WEDNESDAY, Feb. 1, 2017 (HealthDay News) -- Poverty significantly shortens life expectancy and should be regarded as a major health risk factor, a new study suggests.
Researchers analyzed 48 studies that included more than 1.7 million people in the United States, the United Kingdom, Australia, France, Italy, Portugal and Switzerland. They found that poor people were 46 percent more likely than wealthier people to die before age 85.
Among poor people, about 15 percent of men and more than 9 percent of women died before age 85, compared with more than 11 percent of men and about 7 percent of women who were wealthier.
The researchers concluded that being poor was associated with a 2.1-year reduction in life expectancy. This is similar to being inactive, which cuts life expectancy by 2.4 years -- more than the reductions associated with high blood pressure, obesity and heavy drinking, the researchers added.
The study was published Jan. 31 in The Lancet.
Poverty is one of the strongest predictors of illness and early death worldwide, but is often not included in health policies, the researchers said.
"Given the huge impact of socioeconomic status on health, it's vital that governments accept it as a major risk factor and stop excluding it from health policy," said study lead author Silvia Stringhini of Lausanne University Hospital in Switzerland.
"Reducing poverty, improving education and creating safe home, school and work environments are central to overcoming the impact of socioeconomic deprivation," she said in a journal news release.
"By doing this, socioeconomic status could be targeted and improved, leading to better wealth and health for many," Stringhini added.
A low social rank means being powerless to determine your own destiny, said Martin Tobias, a public health consultant from New Zealand. If you're impoverished, you're "deprived of material resources, and limited in the opportunities open to you, which -- the authors imply -- shapes both your lifestyle and your life chances," he wrote in an accompanying editorial.
The U.S. Centers for Disease Control and Prevention has more on life expectancy.
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