The Washington PostDemocracy Dies in Darkness

Rejoice, weekend warriors: A few days of camping tunes up your circadian clock

(David Goldman/AP)

In January, Ariana Huffington, who for years has described herself as a “sleep evangelist,” turned her evangelism on the soon-to-be-inaugurated President Trump. Speaking in Davos, Switzerland, Huffington called Trump “the poster child of sleep deprivation” and argued that he “should be separated from his phone at night, get a full night’s sleep and stop tweeting in the middle of the night.”

Trump sleeps about two to four hours nightly, The Post reported in November. In that regard, the president has something in common with many Americans. We are so delinquent about getting consistent sleep, according to a 2016 report from the Centers for Disease Control and Prevention, that a third of the population snoozes for fewer than seven recommended hours of sleep a night.

Perhaps Huffington should become a camping advocate, too. As the weekend warrior knows, falling asleep may come a little easier when it happens beneath the stars. A new report from the University of Colorado, Boulder, backs up that woodsy wisdom with evidence taken from a small group of campers. A weekend trip was enough to make a difference in the rise and fall of the hormone melatonin, which regulates our biological clock. And a week spent outside in winter — thanks to the exposure to 9 hours of sunlight daily, rather than the artificial stuff — shifted sleep times earlier and reset the body’s circadian clock.

“Living in our modern environments can significantly delay our circadian timing and late circadian timing is associated with many health consequences,” Kenneth P. Wright, a sleep researcher and author of the new study published in the journal Cell, said in a statement. “But as little as a weekend camping trip can reset it.”

Wright’s previous research suggested a week of summer camping was enough to shift sleepers to be more in sync with the rise and fall of the sun. “Lights have a powerful effect beyond vision,” Wright told Popular Mechanics in 2013, when the summer study was published. “When we go abating that internal biological time, there are consequences.”

In the first part of the 2017 follow-up study, Wright and his colleagues wanted to know if less time spent outdoors would have a similar effect. They compared nine campers, who spent two summer days and nights outdoors in Colorado, against five people who stayed indoors for a weekend. They were exposed to a fourfold increase in natural light. Saliva swabs of the weekend campers revealed their melatonin levels rose 1.4 hours sooner each evening.

Although they did not go to sleep earlier than they had during the week, the campers did not stay up any later, either. For those who stayed at home, weekends meant staying up later at night and sleeping in later in the morning. A weekend “phase delay,” as the scientists described it in the study, “contributes to social jet lag on Monday morning.”

The effect was not quite as profound as spending a week outside, but it was still a significant change. “Weekend exposure to natural light was sufficient to achieve 69 percent of the shift in circadian timing we previously reported after a week’s exposure to natural light,” Wright said in the statement.

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The second approach asked a different question — would there be a seasonal difference between a week spent outdoors in the winter vs. the summer? Winter campers, as you would expect, were exposed to fewer total hours of sunlight than summer campers. But the light winter campers received was 13 times stronger than if they had spent a winter week indoors; the scientists attribute this difference to the fact that, during winter, a larger proportion of our light is artificial. The Rocky Mountain campers fell asleep about 2.5 hours earlier, and slept for longer amounts.

“In summary,” concluded the researchers, “our findings demonstrate that the human melatonin rhythm adapts to short summer and long winter nights when living in a natural light-dark cycle — something that has been assumed but never demonstrated with respect to the ‘natural light-dark cycle.’ ”

But camping should not be viewed as a panacea for the sleep-deprived, as Wright made clear in an interview with the BBC. “We’re not saying camping is the answer here, but we can introduce more natural light to modern life,” he said. Unless an effort is made to keep up with a natural cycle, such as early morning outdoor walks and weaning ourselves from screens in the evening, we are likely to return to our indoor habits.

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Sleep experts have long cautioned that disrupted circadian rhythms have lasting impacts. “We are the supremely arrogant species; we feel we can abandon four billion years of evolution and ignore the fact that we have evolved under a light-dark cycle,” University of Oxford circadian neurobiologist Russell Foster told the BBC in 2014. “What we do as a species, perhaps uniquely, is override the clock. And long-term acting against the clock can lead to serious health problems.” Late circadian timing, Wright and his colleagues noted in the new paper, has been associated with poor school performance, obesity and mood disorders.

The authors of the study argued that, even when we cannot get away into a campground for the weekend, lessons from the outdoors can be applied to our indoor lives. Architects could consider funneling more natural light into a building, for instance, Wright said in the statement. He encouraged “lighting companies to incorporate tunable lighting that could change across the day and night.”

And, yes, good sleep hygiene also means letting go of phones and logging off Twitter as you prepare to hit the hay.

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