Modern electrical lighting and the use of handheld devices, combined with limited exposure to natural daylight, is delaying humans’ circadian clocks. A late sleep schedule has been associated with negative cognitive performance and health outcomes, such as daytime sleepiness, obesity and mood disorders.
But a series of experiments, published in the journal Current Biology, suggest eliminating all artificial lights at night to improve your sleep – and one way to do that is by going camping.
Kenneth Wright, professor of integrative physiology at the University of Colorado, Boulder, led the experiments. For the first stage, he sent a group of five healthy, fit individuals in their 20’s and 30’s camping for six days in Colorado around the time of the winter solstice.
Prior to the trip, each individual had their melatonin rhythm assessed in a laboratory setting, after six days of maintaining habitual, self-selected sleep times in their homes. Melatonin rhythm is the most precise marker of a human’s internal biological time.
During the six days in the Rocky Mountains, the group slept in tents at self-selected times and were not allowed to use flashlights, personal electronic devices, or any other form of artificial light.
Immediately after returning from camping, the participants spent 24 hours back in the lab to have their melatonin rhythms reassessed.
Wright and fellow study authors found that the participants went to bed 2.5 hours earlier while camping compared to when sleeping at home, but wake times remained similar, resulting in longer sleep duration during winter camping.
The researchers also reported that the camping group was more active during the daytime, and was exposed to light levels 13 times higher than what they were used to at home.
The second phase of the experiment included a summer weekend camping trip for 14 participants – half of which were female, also in their 20’s and 30’s.
This time, melatonin rhythms were assessed after two days of self-selected sleep times in the “modern environment” of their homes. Then, nine members of the group went camping in Colorado for the weekend, while the other five stayed home. However, those who went camping were allowed to have flashlights and headlamps this time around.
For weekend campers, melatonin onset occurred about 1.5 hours earlier compared to their usual schedules.
Illuminance levels were four times higher for the weekend camping group compared to those who stayed home. Sunrises in particular have a heavy influence on setting biological clocks because of the enriched blue light.
The authors note that the smaller increase of illuminance exposure for the summer group was driven by less light exposure in the modern electrical environment during winter versus summer, and not by a difference in light exposure during the natural winter and weekend summer light-dark cycle.
Previous research already supported the theory that modern electricity affects the sleep-wake cycle. The authors cited another study of Brazilian rubber tappers and hunter-gatherers from the Toba/Qom in the Argentinian Chaco, which found that those with access to electrical lighting had a later circadian clock and sleep timing compared to those from the same communities without that access.
“Our findings also show that a weekend of camping prevents the typical weekend circadian and sleep delay, which is an important contributor to the phenomenon of social jet lag. Specifically, the weekend phase delay in the modern electrical lighting environment contributes to social jet lag on Monday morning because there is a mismatch between biological (circadian delay) and social (awakening early for work/school) timing, the definition of social jet lag,” wrote the authors.
The study results suggest a larger message than simply “unplug and get outside” when experiencing sleep quality issues – the authors also note the potential of future buildings being equipped with lighting that mimics a similar spectrum and intensity as natural light, to help keep our internal clocks in check.