Researchers say they’ve found a community that’s got sleep down to a science. (Photo: Stocksy/Lumina)
What is the natural time for human beings to feel sleepy each night? While it differs slightly from person to person (hello, circadian rhythms!), the overall answer could lie in a tiny, rural town in Brazil called Baependi.
Researchers from the U.K. and Sao Paolo, Brazil, found that people in this town follow a sleep and wake schedule similar to pre-industrial times, suggesting humans have a natural bedtime and wake time.
In the study, scientists asked people there what time they would wake up and go to sleep if they were able to plan their day however they wanted to. Most responded they’d wake up at 7:15 a.m. and go to bed at 10:20 p.m. People outside the town (in the surrounding countryside) wanted to wake up at 6:30 a.m. and go to bed at 9:20 p.m. People who lived in London? 8:30 a.m. and 11:15 p.m.
Naturally, our sleep schedules sync closer to daylight and nightfall, like the bedtimes and wake up times of the people in the Brazilian community. As the sun goes down, the body begins to produce the sleep-inducing hormone melatonin. But modern technology and artificial lighting has skewed sleep schedules later, meaning we stay up later than our ancestors did as the blue light from electronic devices can disrupt nighttime melatonin production. The problem: Most of us still need to get up early for work, so we wind up sleep-deprived.
Don’t blame the variation in preferred bed and wake times entirely on modern-day technology just yet, though: People in Baependi do have electricity and TV. “What we think is happening is that they are exposed to a lot of natural light,” lead author, Malcolm von Schantz, PhD, a professor of molecular neurobiology at the University of Surrey, tells Yahoo Health. “Many have outdoor professions — agriculture and open-cast mining — especially those in the surrounding countryside, where the rhythm was even earlier.”
And this makes sense, given what we know about how natural light affects our internal clocks. A recent University of Colorado study analyzed people in their normal environment (where they had artificial lighting), then on a camping trip (where they were only exposed to natural light) and found that their sleep timing and circadian rhythms shifted by about two hours when camping. “The rhythms of the people in Baependi look a lot like those on the camping trip,” von Schantz explains.
Related: The Exact Time You Should Go To Bed
Setting your sleep schedule straight matters more than you may realize. “There is strong evidence that chronic sleep deprivation has multiple negative effects on our health — mortality in general, obesity, diabetes, cardiovascular disease, and also impaired vigilance and cognition,” says von Schantz.
In fact, past research from von Schantz and colleagues at the University of Surrey studied the effect of chronic sleep deprivation on a molecular level. “Sleep deprivation seems to activate a gene expression program called Conserved Transcriptional Response to Adversity (CTRA), which essentially evolved in response to strong stress in order to prepare for what was — to our ancestors — the likely consequence: physical injury,” says von Schantz. The products of CTRA promote wound healing and limit infection. The problem? In today’s world, stress isn’t always a physical threat leading to injury. And the pro-inflammatory responses likely contribute to negative health outcomes.
So what’s the best way to put snooze first without a weeklong camping trip or a move to Brazil? “Expose yourself to natural light in the morning, and avoid artificial light at night,” says von Schantz. “Unlike our visual system, our circadian system only responds to light at those two time windows — in the morning, when light exposure advances our rhythms; and in the late evening, when it delays our rhythms.” Soak yourself in sunlight in the a.m. and keep the lights to a minimum after dark and you’ll reap the full advancing effect and none of the delaying effect.
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