THURSDAY, Aug. 1 (HealthDay News) -- Putting down your phone and
living for a week with nothing but sunlight and campfires may bring
your body clock in sync with nature's rhythms, a small study
And, researchers found, even avowed night owls turn into early
birds after a week of camping in the woods with no sources of
artificial light -- including smartphones, computers and TVs.
"We've already known that artificial light is keeping us up at night," said lead researcher Kenneth Wright, of the University of Colorado at Boulder. But this study, he said, was an attempt to "quantify" the effect that light exposure, both artificial and natural, may be having on the human body's internal "clocks."
"What we found suggests that it's not just artificial light that's keeping us awake," Wright said. "It's also a lack of daylight."
For the study, reported in the Aug. 1 online issue of
Current Biology, Wright's team recruited eight healthy
adults who stuck with their normal daily routines for one week, and
then spent another week camping together. During the trip, the only
lights allowed were sunlight and campfire light.
At the end of each week, the researchers took saliva samples to
measure study participants' melatonin -- a hormone that becomes
more active in the evening, to help people fall asleep, then drops
off in the early morning so they can wake up bright-eyed.
Typically, Wright's team found that when people were at home
they went to bed after midnight, on average, and rose at around 8
a.m. On the camping trip, however, they turned in earlier and rose
More importantly, the campers' "biological night" kicked in
about two hours earlier, Wright said. That is, their melatonin
levels began to rise around sunset, and then drop off around
sunrise, almost an hour before they woke up.
"So they became much more in sync with the natural world," Wright said.
And what's the big deal about that? It's not clear yet,
according to Wright. "Does it make a difference in how they feel?"
he said. "That's an important question."
What does seem clear, Wright added, is that "the type of light
we're exposed to really does have a big impact on our biology."
And it's possible, he noted, that exposure to artificial light
at night -- and a lack of sun during the day -- are contributing to
some people's sleep problems and morning grogginess.
Past studies have found that in the typical artificially lit
lifestyle, people's melatonin levels do not drop off until about
two hours after they wake up. In essence, Wright said, their
biological night is still in effect even though they are awake.
The new findings are "not surprising," said Dr. Jordan
Josephson, an ear, nose and throat, and sleep specialist at Lenox
Hill Hospital in New York City. He noted that it's known, for
example, that people who do shift work -- and are exposed to
artificial light when the outside world is dark -- often suffer
Another sleep specialist agreed that the findings are not
surprising, but added that they are potentially important.
For one, they may offer an explanation for why melatonin levels
typically don't hit their low until two hours after people wake up,
said James Wyatt, an associate professor of behavioral sciences at
Rush University Medical Center in Chicago.
It would "make much more sense" for the melatonin pattern to
look like that of the campers in this study, Wyatt said.
There are still plenty of questions, he cautioned. "This is a
tantalizing study, but it's preliminary." The experiment, Wyatt
said, needs to be repeated in larger groups of people, and in
Still, Wyatt said, the biological effect was "very consistent"
for all eight campers in this study -- which suggests that a
similar effect would be seen in a larger group.
For now, Wright suggested that if you're someone who typically
stays up late and regrets it in the morning, it wouldn't hurt to
dim the artificial lights and get more sunshine.
"Reduce your exposure to light from the TV and computer at night," he said. "And during the day, get out more. Eat your breakfast outside, or go for a walk in the afternoon."
Wyatt agreed that at the very least, there's unlikely to be a
downside to doing those things.
The U.S. National Institute of General Medical Sciences has more
circadian rhythms and health.
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