If your sleeping patterns are out of sync, the best was to reset your internal circadian clock is an escape into the wilderness for a week, according to a University of Colorado Boulder news release.
Eight participants in a small study spent a week camping in Colorado's Eagles Nest Wilderness using just the sun and glow of a campfire for light.
"At the end of the trip researchers found that the campers' biological nighttimes shifted to start when the sun went down and end when the sun came back up," the University said in a news release.
The change happened in all study participants; those who were self-proclaimed "night owls" turned into "early birds."
"What's remarkable is how, when we're exposed to natural sunlight, our clocks perfectly become in synch in less than a week to the solar day," said CU-Boulder integrative physiology Professor Kenneth Wright, who led the study.
Electrical lighting became popular in 1930s, but has negatively affected the body's circadian rhythm, which tell us when to fall asleep and when to stay awake.
"When people are living in the modern world-living in these constructed environments-we have the opportunity to have a lot of differences among individuals," said Wright, who also is the director of CU-Boulder's Sleep and Chronobiology Laboratory. "Some people are morning types and others like to stay up later. What we found is that natural light-dark cycles provide a strong signal that reduces the differences that we see among people-night owls and early birds-dramatically."
Though the intensity of indoor lighting is reportedly much lower than sunlight, it doesn't change intensity like natural light, according to the researchers:
To quantify the effects of electrical lighting, a research team led by Wright, and including undergraduate and doctoral students, monitored the study participants for one week as they went about their normal daily lives. The participants wore wrist monitors that recorded the intensity of light they were exposed to, the timing of that light, and their activity, allowing the researchers to infer when they were sleeping.
According to the news release, researchers recorded the timing of participants' circadian clocks in the laboratory by measuring the presence of the hormone melatonin. No personal devices were allowed during the study.
By the end of the study, participants' biological "nighttime" allowed them to sleep about two hours later. When they went back to their normal lives, the participants woke up before their biological nighttime was over.
The study was published in the journal Current Biology.
