Modern-day living involves being surrounded by a sea of TV and smartphone screens and floods of electrical light. It is no wonder, therefore, that we struggle to get an early night when there are so many distractions to keep us up late. However, scientists have found a solution to getting bedtime back on track: going camping.
New research, published in the journal Current Biology, concludes that regardless of the season, spending time outdoors in the natural light – while camping, for example – is enough to reset our internal clocks and enable us to get to sleep earlier.
“Late circadian and sleep timing in modern society are associated with negative performance and health outcomes such as morning sleepiness and accidents, reduced work productivity and school performance, substance abuse, mood disorders, diabetes, and obesity,” says Kenneth Wright at the University of Colorado Boulder.
“Our findings demonstrate that living in our modern environments contributes to late circadian timing regardless of season and that a weekend camping trip can reset our clock rapidly,” he adds.
Previous studies by Wright and collaborators showed that daily exposure to electrical lighting at the flick of a switch causes a shift in the internal clock, which results in a delay of around 2 hours and, subsequently, a later bedtime. The team backed up this finding with evidence that shows a shift in the normal fluctuations of melatonin, a hormone responsible for the regulation of the circadian rhythm.
The researchers found that the shift was remedied by a week spent in the summer sun. The internal clock shifted back, which caused people to go to bed earlier, with no change in how long they slept.
While exposure to summer sunlight “fixed” the internal body clock, questions remained. The team wondered how the internal clock would respond to seasonal changes if summer were replaced with winter in the study. They also wondered how quickly the internal clock could be reset in the summer setting – did participants need to be outside for a full week, or could the internal clock be changed more rapidly?
To find the answers, Wright and colleagues conducted two studies. The first assessed the impact of the winter natural light-dark cycle on the internal clock compared with electrical lighting. The second evaluated whether the internal clock could be changed over a weekend of exposure to the summer natural light-dark cycle.
The first study involved sending a group of five active individuals camping for a week in Colorado during winter. The researchers timed the study so that the participants went around the time of the winter solstice – when the days were shortest.
The participants were not allowed cell phones or flashlights so that their sleep and hormone rhythms could be examined without the interference of technology that emits artificial light. The results were compared with those taken after the participants spent a week in their modern electrical lighting environment.
After analysis, the team revealed that modern lifestyles reduce light exposure in the winter by 13 times. Spending more time outdoors caused the study participants to go to bed earlier. In a similar way to the results of the previous research, the internal clock and rising of melatonin levels shifted earlier by more than 2.5 hours.
The second study explored whether a weekend of camping in the summer was enough to shift the internal clock.
A total of 14 individuals were split into two groups. Nine of the participants went camping in the Rocky Mountains of Colorado for a weekend, but this time they were allowed flashlights and headlamps, and five of the participants spent the weekend in a modern environment with electrical lighting.
A weekend of camping was, as expected, enough to shift the internal clock. Being exposed to the natural light-dark cycle prevented typical weekend patterns of staying up late and sleeping in, and it stopped the individual’s internal clocks from being shifted later.
Although modern conveniences can leave us out of sync with our internal clocks, the research shows that there is an easy solution: light exposure. A weekend of camping could be just the remedy for someone in need of an early night.
Wright points out that consistency is the key. He says that to stay on track with sleeping patterns, a regular schedule is crucial. Among other solutions, Wright suggests that “increasing daytime exposure to sunlight and reducing nighttime exposure to electrical lighting” may help.
“Our findings highlight an opportunity for architectural design to bring in more natural sunlight into the modern built environment and to work with lighting companies to incorporate tunable lighting that would be able to change across the day and night to enhance performance, health, and well-being.”
Future work for the team revolves around finding out how much sunlight is required to adjust the internal clock in either direction, and exploring the link between circadian cycles, exposure to light, and other aspects of health.