Heading to the wilderness for a weekend camping trip this winter could help improve sleep, according to a study from researchers in the U.S., published February 2.
A team of researchers from the University of Colorado, Boulder, found that spending at least a weekend camping with no artificial light sources -- enjoying natural sunlight during the day and total darkness at night -- can help reset the body's circadian rhythm and help people fall asleep.
Circadian rhythms are essentially the internal "body clock," defining the body's day and night with physical, mental and behavioral changes in response to light and darkness, based on a cycle of approximately 24 hours. Disruption to these rhythms can lead to sleep problems and various physical (such as diabetes), psychological, cognitive and behavioral consequences.
In 2013, a team of researchers, led by lead author Kenneth Wright, carried out a first study investigating the modern lighting environment's impact on the body clock.
Volunteers were sent on a week-long camping trip where they were exposed to four times more natural light than usual. On their return, the researchers found that the characteristic rise in melatonin -- a hormone that promotes sleep and prepares the body for nighttime -- happened two hours earlier, around the time of sunset.
To further understand the impact of seasonal changes on the biological clock and how quickly the body adapts to lighting environments, the team carried out a second study, the results of which were published February 2 in Current Biology.
The scientists picked 14 volunteers, nine of whom went camping for a weekend in Colorado while the remaining five stayed at home. The campers maintained their regular weekday sleep schedule rather than sleeping in later like those who stayed at home. Two days after they returned, after testing their saliva for melatonin, the researchers found that the campers' melatonin rise had shifted 1.4 hours earlier.
They then sent five other participants on a week-long camping trip around the time of the winter solstice. Their melatonin levels were then tested every hour for 24 hours. The campers had been exposed to an average 13 times as much natural daylight as in their usual weekday environment. All the participants went to bed earlier and slept for longer. Their melatonin levels also began to rise 2.6 hours earlier than usual.
The researchers conclude that since their body clocks weren't thrown off by artificial light, the campers' biological night naturally lengthened in line with the season, as with many animals.
When camping trips aren't an option, the authors recommend maximizing exposure to natural daylight and shutting off smartphones and laptops well before bedtime.
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