Estimated read time: 3-4 minutes
This archived news story is available only for your personal, non-commercial use. Information in the story may be outdated or superseded by additional information. Reading or replaying the story in its archived form does not constitute a republication of the story.
SALT LAKE CITY — Before the days of electric light, most of the earth’s population went to bed with the sunset and awoke with the sunrise. A new study sheds light on what may be a need to return, if not for a small time, to our ancestral schedule.
Professors and students at the University of Colorado, Boulder recently published a study in the scientific journal Current Biology outlining the effects of electric light on sleep patterns.
Kenneth Wright, director of the Sleep and Chronobiology Laboratory at the university, said electric light has an interesting effect on the way our body sets its internal clock.
“Light affects our physiology in many ways, vision being the most obvious,” Wright said. “However, beyond conscious vision, light provides time cues that synch our internal clocks to the external environment.”
Wright and his team were interested in tracking the impact electric light might have on the complex brain patterns that dictate the way we sleep and schedule our days.
“We can measure the time of our internal clocks by measuring levels of the hormone melatonin,” Wright said. “Melatonin levels are low during the day and tend to rise about two hours before we go to sleep at night and remain high throughout the night. They then return to low daytime levels shortly after we awaken in the morning.”
Light affects our physiology in many ways, vision being the most obvious. However, beyond conscious vision, light provides time cues that synch our internal clocks to the external environment.
–Kenneth Wright
The team of researchers tracked how much natural and artificial light a group of test subjects were exposed to over the course of a week. After the week, their melatonin levels were tracked every hour by the researchers in the lab.
Artificial light, Wright said, can reset our internal clocks to schedules that may not lead to healthy sleep habits.
“The internal clock is important as it dictates much of our physiology and behavior,” Wright said, “including the time of day when we eat, when we perform at our best and when we sleep.”
After the subjects were monitored performing normal daily routines, they were taken camping in the Rocky Mountains for a week. The campers were allowed only campfire light at night, and no electronic light-emitting devices were brought on the trip.
“When camping, people were exposed to light levels that were 400 times brighter than during their normal daily activities,” Wright said. “This increased exposure to sunlight lead to an earlier timing of the internal clock.”
After a week in the mountain, the melatonin levels of each subject were again tested, and the researchers found the levels had adjusted to earlier waking and sleeping times.
“This shift,” Wright said, “can make it easier for a person to wake up in the morning, as the internal clock is no longer promoting sleepiness.”
Wright said while it may not be practical for everyone to go camping regularly, there are things people can do to minimize the effects artificial light has on the internal clock. He suggested increasing daily exposure to natural sunlight, opening blinds and curtains while indoors and dimming electronics at night to help keep a more natural schedule of sleep and wakefulness.
