Our circadian clocks are governed by the natural rise and fall of melatonin, the “sleep hormone” that cues off of light. In the evenings, melatonin levels rise, telling our bodies it’s time for bed. As night turns to morning, our levels drop back down, telling us to wake up, eat, and get moving. When our internal clocks are more in sync with the season’s natural light-dark cycle, we tend to get better rest, our moods and energy levels improve, and we have less risk of weight gain and diabetes.
Which is why camping — basking in the natural outdoor light — is a proven boon for healthy sleeping. But what about in the winter, when there's less light to go around? A new study finds that even in the darker months, the sleep benefits of camping aren't diminished one bit.
In 2013, sleep researchers from the University of Colorado Boulder showed that our everyday exposure to indoor lights, smartphones, and screens delays our internal clocks by a whopping two hours. They also showed that camping could fix this. After a week spent in the Rocky Mountain backcountry, participants’ internal clocks shifted, prompting them to go down and wake up earlier than usual.
For this latest round of research, the scientists sent five brave souls into the rugged Rockies for a week right around winter solstice. They stripped them of flashlights, smartphones, or any type of unnatural light. From the sun alone, they were exposed to 13 times more light than they would’ve been at home.
The participants were free to hit the sack and wake up whenever they wanted. Throughout the week, they turned in 2.3 hours earlier than they did normally — but awoke at the same times, scoring them extra sleep. Because this pattern persisted all week, it shows they weren’t simply “catching up” on sleep, says lead researcher Kenneth Wright.
Regardless of sleep duration, the key finding here was that the participants’ circadian clocks had shifted 2.5 hours earlier during their trip. This was determined by measuring their melatonin fluctuation patterns after the weeklong trip and comparing them to those induced by a regular, artificially lit winter environment.
“We showed that when exposed only to natural light, humans indeed respond to seasonal changes in light by shifting the timing of their internal clocks earlier,” Wright says. “We already know that humans respond to seasonal changes in other ways, such as developing seasonal depression.” It only makes sense that sleep timing is also affected — and that without blaring indoor lights and blue-light-emitting screens, we’d come a lot closer to rising with the sun and going down when it sets.
Better yet, according to Wright’s second new study, it only takes a weekend to adjust. After ensuring 14 volunteers had gotten two nights of solid rest, his team sent nine people into the Rockies for the weekend while five stayed back in the lab. After their short time in the woods, the campers’ circadian clocks moved ahead 1.4 hours. “By camping for just a few days, you can get 60 percent of what you can get in a whole week,” Wright says.
To continue gleaning the health benefits of resetting your internal clock, you must make some changes once you come home. “If you go for a camping weekend but then don’t keep close to that light-dark schedule, your internal clock will adapt right back,” Wright says. “Start your days with an early-morning walk. Or, if you exercise before work or during your lunch break, take your workout outdoors. At night, dim the lights and put that smartphone away.”
You can also use a therapy light to prolong your camping sleep schedule — or even replace camping altogether if a trip isn’t feasible. “Using a light box in the morning, and dimmer and fewer lights in the evening can also shift your clock earlier,” Wright says. “But my best advice would be to spend your weekend outdoors and then use a light box to keep your clock early.”