Camping in the wilderness can do more than just give us an appreciation for nature. According to a study published in Current Biology, it can also synchronize our internal clocks to the solar day, allowing us to normalize melatonin levels.
The study comes from researchers at Colorado University-Boulder, in a state renowned for scenic camping sites. Taking advantage of their locale, the team from the Sleep and Chronobiology Laboratory monitored eight participants (six men, two women aged an average of 30 years) for a week as they went about their normal activities.
The researchers then monitored the men and women during a second week as the they went camping in Colorado’s Eagles Nest Wilderness without access to flashlights or electronic devices.
For the researchers to gather accurate metrics, they had the participants wear wrist monitors, which recorded the amount of light to which they were exposed, the timing of the light, and the participants’ activities, including sleep.
At the end of both weeks, researchers recorded the participants’ circadian clocks in their lab by measuring melatonin, a hormone that signals the beginning of our biological nighttime.
Results show that on average, the participants’ biological nighttimes began about 2 hours later when they were exposed to electrical lighting in their normal lives, compared with when they were camping and only exposed to sunlight and campfires.
In addition, the participants woke up before their biological night had ended during their normal lives.
Apparently, the researchers say, all of the participants’ sleep patterns synchronized with sunset and sunrise, even though some people in the study were either night owls or early birds in their normal lives.
The study’s authors note that although electric light is one of the most important human discoveries, it affects our sleep and daily rhythms. These physiological and behavioral rhythms were evolved in the natural light-dark cycle, but now electrical lighting is disrupting them.
Professor Kenneth Wright, leader of the study from CU-Boulder, says:
“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.
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.”
Because our ability to simply hit a switch and fill a room with light has been available largely since the 1930s, and because we now go to bed reading tablets and smart phones, our natural cycles have been altered.
“What’s remarkable,” says Wright, “is how, when we’re exposed to natural sunlight, our clocks perfectly become in synch in less than a week to the solar day.”
This study illuminates how much both natural and artificial light effect our biological rhythms, and the researchers offer some advice for how to combat a drift in rhythms at night:
- Get more sunlight in the morning and midday to nudge internal clocks earlier
- Dim electrical lights at night and skip late-night TV or laptop use to help internal clocks stay more in synch with the solar day.
The researchers conclude that their findings are significant in understanding how modern light exposure can contribute to disruption of sleep and circadian clocks.
So those thinking of booking a camping trip may want to proceed. Just leave the laptop at home.